LS7C Midterm 2

Describe the cross-bridge cycle in a skeletal muscle

1. Myosin head binds ATP => binding of ATP allows myosin head to detach from actin and readies it for attachment to actin 2. Myosin head catalyzes hydrolysis of ATP to ADP and Pi => results in conformational . change in which myosin head is cocked back. Because ADP and Pi bound rather than released myosin head in high energy state => here is where cycle is paused, myosin head not attached to actin 3. Myosin head binds actin, forming cross-bridge 4. When myosin head binds actin, myosin head releases ADP and Pi => results in another conformational change in myosin head called power stroke => myosin head pivots forward and generates force, causing myosin and actin filaments to slide relative to each other => sarcomere shorten

Trace the flow of blood through the human circulatory system.

1. deoxygenated blood enters the right atrium from the venae cava 2. deoxygenated blood passes right atrium => atrium contracts and blood moves through atrioventricular (AV) valve into the right ventricle 3. right ventricle contracts, blood is pumped through the pulmonary valve to the lungs for oxygenation---Right ventricle is thinner so it ejects blood at a lower pressure which allows blood of the pulmonary circulation to move at a lower rate allowing more time for gas diffusion 4. oxygenated blood returns from the lungs through the pulmonary veins and enters the left atrium of the heart 5. left atrium contracts, blood is pumped through a second atrioventricular valve into the left ventricle 6. thick muscular walls of the left ventricle eject the blood through aortic valve under high pressure to the body Deoxygenated blood flows from the Body → Superior and Inferior Vena Cava → Right Atrium → Right Ventricle → Pulmonary Artery → Lungs Oxygenated blood flows from the Pulmonary Vein → Left Atrium → Left Ventricle → Aorta → Body

The same red blood cell leaves the heart again, but this time instead of traveling to the liver, it travels to a skeletal muscle that is actively respiring. At each point on its journey (A-D), determine the oxygen saturation level (%) of the hemoglobin molecules found in this red blood cell. A B D C (active skeletal muscle) PO2 = 20 mmHg What is the approximate O2 saturation at point D? A. 75% B. 25% C. 40% D. 10% E. None of the above

10%; when active respire, both PO2 dec to 20 mmHg and also pH dec

Given the temperature readings in the topmost tube (in the system diagrammed), which would be reasonable temperatures for points 1 to 5 in the lower tube? arrow diff direction top tube: 10, 20, 30, 40, 50 ˚C

20 - 30 - 40 - 50 - 60

How many molecules of O2 can a single hemoglobin molecule carry when fully saturated?

4

If a muscle fiber is 10 mm long and its sarcomeres average 2.0 µm in length (close to their maximal force generation), how many sarcomeres are in series along the fiber's length?

5000 10 mm = 10,000 µm. The number of sarcomeres is therefore 10,000 µm /2 µm = 5,000 sarcomeres.

Given the temperature readings in the topmost tube (in the system diagrammed), which would be reasonable temperatures for points 1 to 5 in the lower tube? arrow same direction top tube: 10, 20, 30, 40, 50 ˚C

90 - 80 - 70 - 60 - 5050 - 40 - 30 - 20 - 1020 - 30 - 40 - 50 - 6040 - 30 - 20 - 10 - 0

Relate the processes of digestion, nutrient absorption, and energy acquisition to homeostasis.

=Nutrient absorption => not homeostatic, just absorbs everything H+ (pH concentration) => homeostatically regulated, use secretin => in diagram it is response that is being regulated Gastrin => make pH lower => homeostatic CCK in response to fat => homeostatic

If a hair cell bends toward the kinocilium, K+ channels will open and the cell will _________. A. Depolarize B. Hyperpolarize C. Stay at the same membrane potential

A

One of the functions of the cardiovascular and respiratory systems is to rid the body of CO2 . Where does the CO2 come from? A. CO2 is a breakdown product of the carbohydrates oxidized in cellular respiration. B. CO2 is a breakdown product of the carbohydrates reduced in cellular respiration. C. CO2 is produced when inhaled oxygen combines with carbon atoms from carbohydrates. D. CO2 is produced when the oxygen atoms of water combine with carbon atoms.

A

Suppose the stereocilia of one hair cell become permanently bent toward the kinocilium. What will most likely happen as a consequence?

A single pitch will be constantly perceived depending on the hair cell's location

Evaluate the molecular effect of a stimulus on a sensory pathway.

A stimulus causes some sort of conformational change that allows neurotransmitters to be released, usually turns the pathway on

If a skeletal muscle is no longer able to make enough ATP, then: A) actin and myosin in the sarcomeres will remain bound. B) actin and myosin in the sarcomeres are in the unbound state. C) there will be low levels of acetylcholine at the motor endplate. D) the muscle will be unable to shorten.

A; ATP is required to break the association between actin and myosin. If there is no ATP available, then myosin will stay bound to actin and the sarcomere will maintain its shortened state.

What is required to separate actin and myosin during sarcomere contraction?

ATP

Compare and contrast different forms of nitrogenous waste and their effect on osmotic balance.

Ammonia - produced by the breakdown of proteins - contributes to osmolarity - water soluble - Fish able to excrete ammonia directly into water through gills by simple diffusion=> process not energetically expensive - Most toxic- need lots of water to dilute toxin Urea - Mammals, many amphibians, sharks, and some bony fish excrete nitrogenous waste in this form - in mammals produced in liver, carried to kidneys via blood where it is eliminated - contributes to osmolarity - less toxic than ammonia but takes more energy to make and water to excrete - need energy to convert and to release concentrated urea in water - water soluble Uric Acid -Least toxic -Birds, reptiles and many arthropods - Most energy lost and most energetically expensive -not dissolved in water (not water soluble), it does not exert osmotic pressure and is eliminated with minimal water loss

Explain heart muscle contraction in response to an action potential.

Ions flow into the SA node → action potential fired → atria contractIons flow into AV node → action potential → travels to Bundle of His → Purkinje fibers → ventricles contract 1. SA node initiates heartbeat that generates AP through atria => atria contract At the SA node, where heartbeat is initiated :Sympathetic stimulation speeds up heart rate Parasympathetic stimulation slows downheart rate 2. SA node activates AV node, which is activated and fires 3. Action potential from AV node transmitted to bundle of his and then Burkenjie fibers (why see delay in EKG) 4. Depolarization spreads from modified muscle fibers though entire ventricle => ventricle contract

Chemoreceptors in the circulatory system detect changes in circulating pCO2. If CO2 concentrations get too high, the rate of ventilation increases. Why does this make sense?

It makes sense because tissues that are more actively working produce more CO2 and, therefore, need more O2. During cellular respiration, carbon dioxide is produced as sugars are oxidized.

Describe the changes in blood pressure and muscle contraction that occur during the cardiac cycle.

Blood pressure goes from higher to lower pressure => "pressure gradient" muscle contraction => increases blood pressure Muscle relaxation => decrease blood pressure Diastole (ventricles are filling) is the relaxation of the ventricles - atria contract and the ventricles fill with blood - ventricle pressure low Systole (ventricles are emptying) is the contraction of the ventricles - blood is pumped from the heart into the pulmonary and systemic circulations - ventricle pressure high During diastole => pressure in atria is high and low in ventricle During systole => pressure in LV is high and low in the aorta

Which of the statements explains why there is an elastic layer found in arteries but not veins?

Blood pressure is higher in arteries than veins, and the elastic layer helps maintain the structure of the artery. With each heartbeat, there is a volume of blood pushed through the arteries at high pressure. The elastic layer helps to absorb the increase in pressure with some distention of the artery, and the artery is able to return to its normal shape.

When do the ventricles depolarize? A. P wave B. PR segment C. QRS complex D. ST segment E. T wave

C

which of the following is not true of muscle fibers? A) Muscle fibers have more than one nucleus. B) Actin and myosin filaments are arranged in parallel along the longitudinal axis on the myofibril. C) Many muscle fibers are packaged into a muscle fibril. D) Movement is generated by muscles when actin filaments interact with myosin filaments

C

Insects, reptiles, and birds excrete uric acid as their form of nitrogenous waste. Uric acid is much less water-soluble than urea. Why does this allow these organisms to conserve more water than a mammal with extensive kidney tubules for water reabsorption? A. The high solubility of uric acid allows the excretory system to reabsorb water. B. Uric acid levels stay high in the blood maintaining a strong osmotic gradient, which allows water to be reabsorbed. C. After precipitation*, uric acid no longer influences osmolarity; water returns to the hypertonic tissues. D. After precipitation*, uric acid no longer influences osmolarity; water leaves the hypertonic tissues.

C Reduced osmolarity makes filtrate hypotonic to the surrounding tissues

Predict how altering osmolarity or membrane permeability in the nephron will affect kidney function.

Lowered osmolarity (decrease ADH) causes Na+ and Cl+ reabsorption in the kidneys and less concentrated urine => increase in urine => more dilute urine Increased osmolarity causes increased levels of ADH. This will add aquaporin channels that allow more water to be reabsorbed. This causes the concentration of urine.Loop of henle dependent on membrane permeability

Explain the role of hormones in regulating the digestive system

Fats in the duodenum secrete CCK which makes the gall bladder release Bile to break down fats Stomach acid in the duodenum secretes secretin which influences the pancreas to secrete bicarbonate to neutralize it

The conformational change in opsin, triggered by the absorption of light by retina, activates a G protein. What do G proteins do in the cell?

G proteins influence the activity of other proteins and enzymes in a cell.G proteins can trigger the synthesis of second messengers.G proteins contribute to signal pathways.

Explain what is meant by the phrase counter-current multiplier.

Generates concentration gradients instead of maintaining them like countercurrent exchange A system that generates a concentration gradient as two fluids move in parallel but opposite directions The loop of Henle acts as a counter-current multiplier Loop of Henle generates countercurrent (concentration gradient) by actively transporting solute (electrolytes) out of the ascending limb and allowing water to diffuse out of the ascending limb (filtrate enters and leaves loop with same concentration)Allows water to be reabsorbed by the blood from the descending limb

Explain how the nervous system regulates breathing and how this relates to homeostasis.

Homeostatic Control of Breathing: Oxygen and CO2 are homeostatically regulated Stimulus - O2 level decrease/fall and CO2 levels increase/riseSensors Chemoreceptors - (in brain) sense CO2 and H+ concentrations Aortic bodies - (in heart in the aorta) sense O2 and H+ concentration in blood going into the body Carotid bodies - (in neck) sense O2 and H+ concentration in blood going to the brain Sensors detect decrease in O2 levels and increase CO2 levels Effector→ stimulate motor neurons→ activate respiratory muscles and diaphragm to contract more strongly or more frequently (stronger and faster breathing) Response decreased levels of CO2 increased levels of O2 in blood Most important factor in control of breathing is amount of CO2 in blood

Evaluate how changes in cellular physiology (i.e. altering transporters or cell-cell adhesions) could affect nutrient absorption

If you break concentration gradient then things will not flow/travel the right way - break Na+/K+ => then no Na+ gradient, so can't break glucose and protein into cell -beak cell-to-cell junction => then no impermeable layer and Na+ will go straight through with no regulation -No ATP => Na+/K+ transport cannot work => no gradient

Filtration is usually the first step in the excretory process. What types of filtration typically occur? Select all that apply.

Filtration removes water from the blood. Filtration removes substances dissolved in the blood.

Freshwater fish are in a hypotonic environment. In which direction do their gill chloride cells move chloride ions in this environment?

Freshwater fish have chloride cells that actively move chloride ions into the gills, with sodium ions following. To keep ion balance, freshwater fish pump chloride ions, with sodium ions following, into the body through chloride cells on the gills. This also compensates for the water freshwater fish take in from living in a hypotonic environment. As well, freshwater fish produce large volumes of urine to remove excess water.

Glucose enters the epithelial cells of the small intestine against its concentration gradient. Select the best explanation from the statements.

Glucose is co-transported with Na+, which moves down its concentration gradient into the cell.

Increased ADH secretion__________ urine output A. Increases B. Decreases C. Has no effect on

b

The partial pressure of one gas in a mixture is:

its fractional contribution to total pressure of the mixture.

The power stroke corresponds to which event in muscle contraction?

sliding of actin relative to myosin filaments

What is the primary function of a statolith?

to determine the direction of gravity

Relate partial pressure and Boyle's Law to ventilation and gas exchange

Partial Pressure - fractional concentration of gas multiplied by the total atmospheric pressure => (fractional concentration relative to other gases) X (atmospheric pressure) Boyle's law => Pressure of a gas increases, as volume of container decreases, the pressure of a given mass of an ideal gas is inversely proportional to its volume at a constant temperature In lung => Increase volume --> lower partial pressure (inhalation)Decrease volume => increase partial pressure (exhalation) Air pressure in lungs compared to air pressure outside of lungs determines whether air is coming in or out => Gasses always travel from an area of higher partial pressure to an area of lower partial pressure Reason why pO2 changes as go up, the O2 concentration is not changing, but the atmospheric pressure is =>sea level => more pressure => so higher partial pressure Higher elevation => less pressure => less partial pressure

Assuming that active transport of electrolytes stop in the ascending limb, what would you predict the comparative composition would be of the filtrate at points a and e in the figure?

Points a and e have similar composition.

In which of the heart chambers would deoxygenated blood be found?

R atrium &R ventricle

extra about muscle

Smooth muscle - contracts more slowly, found in arteries, respiratory system, digestive pathways Striated muscle - contracts quickly, found in skeletal and cardiac muscles Muscle force and shortening velocity are inversely related The faster a muscle fiber shortens, the fewer cross-bridges can form within it Muscle fibers generate maximum force at intermediate lengths, b/c most overlap between myosin and actinIf too far away, not enough overlapIf too close, the myosin bumps into z-discs With Botox protein, it binds to vesicles and doesn't let them fuse to the membrane, no ACh released Muscle in relaxed state = myosin is bound to ADP and Pi, not ATP and not actin Change contraction force => if muscle fiber is restimulated before it has completely relaxed, second twitch is added on to first twitch, resulting in summation. If stimulated so rapidly that it does not have an opportunity to relax at all between stimuli, a maximal sustained contraction known as tetanus occurs

Evaluate the physiological consequences of altering the structure/function of skeletal muscle components (e.g., SR, myosin, troponin).

SR cannot release calcium => muscle cannot contract because can't remove tropomyosin Troponin cannot be bound to => muscle cannot contract Myosin cannot unbind => muscle never relax

what region correspond to heart plateau phase?

ST wave- after depolarize (which is QRS); this is where Ca+ move in and K+ move out

Identify cellular, molecular, and protein components involved in muscle contraction and explain their role.

Muscle cell - cell that contracts Motor cell - cell that relays signal to muscle cell to contract through the release of acetylcholine Actin filaments - (thin filaments) double helix that is encased by protein tropomyosin Myosin filaments - (thick filaments) myosin heads sticking out Calcium - stored in sarcoplasmic reticulum, binds to troponin → change in shape Troponin - bound to tropomyosin Tropomyosin - wound around actin, blocking myosin binding sites ATP - helps myosin head move and detach from actin Action Potential in muscle - allows influx of Na+ions depolarizing the cell and allowing opening of ca2+ channels Muscle fiber - elongated cells that use ATP generated through ATP

Continued glucose transport into cells lining the lumen of the small intestine requires a _________ concentration gradient and a transmembrane protein that is a _________.

Na+; Na+-glucose cotransporter

Relate food consumption to energy acquisition

Need to eat food in order to get energy and nutrients our body cannot make (cannot by synthesized by the body) => "essential" amino acids and minerals Minerals => Ca2+, Na+, K + => allow our cells to function, iron (vitamin B) used by hemoglobin to transport blood, vitamin C used for ECM, vitamin D help with calcium uptake

What effect does the nervous system have on the heart rate?

Stimulation by parasympathetic nerves causes the heart rate to slow down. and etc

The body fluid of sharks has a much lower concentration of sodium chloride than that of the surrounding seawater, and sharks are able to remain in osmotic equilibrium with the external environment. How can this be the case?

Sharks store enough urea to match the total solute concentration of the surrounding seawater. Urea also contributes to the solute concentrations within a cell. By storing urea in the tissues, osmotic balance can be achieved without storing more sodium than can be tolerated by the shark's body.

Relate water balance and kidney function to changes in blood pressure

Overhydrated/decrease in blood osmolarity => hypothalamus solute concentration low → no ADH (vasopressin) released → collecting duct is not permeable to water → water stays in urine → large volume of diluted urine and decreased blood pressure Dehydrated/increase in blood osmolarity→ Hypothalamus sense solute concentration high => releases ADH (vasopressin) → increased permeability of collecting duct to water → water reabsorbed into blood → small volume of concentrated urine and increased blood pressure Low blood pressure (low Na+) → kidneys secrete renin → angiotensin to angiotensin I → (in lungs) angiotensin I to angiotensin II → hormone causes arterioles through body to constrict and direct blood back to heart => adrenal cortex secretes Aldosterone → distal convoluted tubule increases reabsorption of sodium and water into the blood → increases blood volume → increases blood pressure Too much Na+ in blood => reduces the ability of your kidneys to remove water. This will result in a higher blood pressureHigh blood pressure (high Na+) → heart secretes ANH → ANP secretion → distal tubule takes up more sodium and water → decreases blood volume → decreases blood pressure increase blood volume => increase BP decrease blood volume => decrease BP

Is the pressure in the atrium or ventricle higher when the atrioventricular valve closes?

P ventricle exceed P in atrium

The ventricles finish filling with blood after the _______.

PR segment

What would happen to a mammalian heart if the nerves leading to it were severed?

The heart muscle would continue to contract but its contraction rate may change. The SA node depolarizes at regular intervals independently of the autonomic nervous system. If the nerves were severed to the heart, this would affect inputs related to increasing heart rate during the fight-or-flight response, for example.

Explain the relationship between surface area-to-volume ratio and gas exchange efficiency.

The rate of diffusion is directly proportional to the surface area over which exchange occurs and to the concentration difference, and inversely proportional to the distance over which the molecules move (or the thickness of the barrier) => diffusion is increased by a large surface area for exchange and a short diffusion distance => lungs have large surface area and small volume to allow diffusion of O2 in lungs to keep up with O2 supplied by ventilation Greater surface area to volume ratio→ easier to diffuse across membrane (rate of diffusion is directly related to surface area), more efficient gas exchange

The percent maximum force that a muscle fiber produces is plotted against the estimated number of myosin cross-bridges formed with actin in the scatterplot. Given this, which statement is correct?

The scatterplot shows a positive correlation between force and number of cross-bridges. The data plotted here are quantitative data representing discrete data (for example, you cannot have half of a cross-bridge). In addition, that data show a positive correlation between the number of cross-bridges and the percent force. That is, as the number of cross-bridges increases, so does the force.

What is the purpose of having three semicircular canals in mammalian vestibular systems?

The three semicircular canals allow the animal to detect motions of the head in three different planes.

What function do collagen and elastin have in arteries?

They provide elastic rebound of the arterial wall to help smooth out blood flow.

Describe the changes in muscle contraction, volume, and pressure that occur during ventilation.

Tidal Ventilation - air is drawn into lungs during inhalation and air is released from lungs during exhalation Inhalation: Diaphragm contracts (moves down) → thoracic cavity expands (volume expands/increases)→ air pressure in lungs is less than outside of lungs → air is drawn in (inhalation) => negative pressure draws air into the lungsMore volume => less pressure Diaphragm expands/relaxes (moves up) → thoracic cavity contracts (volume decreases) → air pressure in lungs is higher than outside of lungs → air is pushed out => positive pressure forces air out of the lungs Lower volume => high pressure For relaxed breathing, the diaphragm controls the inhalation and the exhalation is the product of elastic recoil of the lungs and chest wall

Color vision in vertebrates is made possible by cone cells. t or f

T

In the disease elephantiasis, lymph vessels become blocked because of infection with parasitic worms. Which of the processes would be impacted by this disease?

the return of excess interstitial fluid to the bloodstream If the vessels were occupied by worms, then the amount of fluid that can enter the vessel would be reduced. The reduction of fluid entering the lymph vessel would result in decreased fluid returned into the circulatory system at the venae cava to the heart.

Which photoreceptor cells are primarily responsible for allowing you to read a newspaper in a dimly lit room?

the rod cells in the retina

Water moves out of the collecting duct because:

the solute concentration of the interstitial fluid is higher than the solute concentration in the collecting duct. Water moves to regions of higher solute concentration by osmosis. Solute concentration is low in the collecting ducts because ions are pumped out of the ascending limb of the loop of Henle and distal convoluted tubule, reducing solute concentration to a level lower than that in the interstitial fluid. Water then leaves the collecting ducts by osmosis.

What determines the specific wavelength of light absorbed by a cone cell?

the type of opsin present in the membrane There are different types of opsin found in the membranes of cone cells. Each responds to a different wavelength of light.

Referring to the figure shown, identify which type of cell-cell interaction is most likely to force the products of digestion to be absorbed across microvilli of intestinal cells, rather than allowing them to leak between cells.

tight junction

The primary function of the loop of Henle is:

to generate a concentration gradient between the inner medulla and outer cortex.

Which most likely happens if you shift your gaze from the TV on the other side of the room to look closely at a stain on the front of the shirt you are wearing?

Your lenses become more rounded.

The duct that connects the pancreas to the duodenum can sometimes become blocked. What is the result? A) The digestive enzymes back up into the pancreas and may start to digest the pancreas. B) The digestive enzymes are not affected because they are stored in the gallbladder until they are needed in the duodenum. C) Nothing happens, because the pancreas does not produce digestive enzymes D) .The digestive enzymes produced by the pancreas still enter the duodenum because they travel by the blood to reach the duodenum, not by a duct. E0 The digestive enzymes produced by the pancreas enter the large intestine instead, and digestion proceeds as normal.

a; If the pancreatic duct becomes blocked, pancreatic enzymes would build up in the pancreas and could digest the pancreas.

Mark A for True or B for False Calcium is necessary for contraction.

a; Like skeletal muscle, cardiac muscle contains myofibrils

Skeletal muscle appears striated with light and dark regions. Which of the following is found in the dark regions?

actin & myosin

What drives the secretion stage that occurs in animal excretory systems?

active transport

The countercurrent arrangement of the two limbs of the loop of Henle becomes a multiplier of electrolyte concentration due to which other characteristic?

active transport of electrolytes out of the ascending limb

How does cooperative binding by hemoglobin increase O2 uptake into blood?

after bind 1 O2, affinity for binding increases. max O2 uptake in high O2 area, and let rapid saturation of O2 binding sites for hemoglobin b4 blood leave capillaries surroudning aveoli

Individuals who experience an asthma attack have difficulty breathing. From the discussion of bulk flow, what do you think happens to these individuals' airways that makes it difficult for them to breathe?

airflow resistance inc, so decrease flow of air. bc diameter airway decrease, bc of smooth muscle contraction in airway wall

Which of the substances are removed from the filtrate and returned to the blood during the reabsorption step? Select all that apply.

amino acids sugars vitamins electrolytes

In the figure, at which labeled location will NaCl be at its highest concentration relative to the other solutes in the filtrate?

at bottom

ACE inhibitors are drugs that inhibit an enzyme called ACE that converts angiotensin I into angiotensin II. Treatment with an ACE inhibitor will cause blood pressure to _________. A. Increase B. Decrease C. Stay the same

b

Mark A for True or B for False In a muscle affected by Botox, the cell will become hyperpolarized

b

When the volume of blood passing through the kidney increases, renin production by the kidney will most likely _________. A. Increase B. Decrease C. Stay the same

b

The kidney functions to maintain:

water balance

Given a selectively permeable membrane that is permeable to water but not to a particular solute, and given that there are different solute concentrations on the two sides of the membrane, draw a diagram showing the direction of water movement. Label the side with the higher osmotic pressure.

water move from low solute to high solute/high osmolarity presure

Antidiuretic hormone (ADH) controls the permeability of the collecting ducts to:

water. ADH increases the permeability of the collecting ducts to water, causing the movement of water from the collecting duct to the interstitial fluid and resulting in more concentrated urine.

Which of the groups of vertebrates below has the greatest number of cone cell types? canines humans birds

birds

The rocks and sediments in the gizzards of birds break apart food mechanically. Which structures in vertebrates have a similar function?

break food apart mechanically, like teeth do

Some animals, such as rabbits, whose digestive systems include hindgut fermentation, re-ingest the products of digestion. What function do you think this serves?

by eating products of cecum, absorb additional nutrients

Vertebrate smooth muscle cells are activated when Ca2+ binds to:

calmodulin.

What are two mechanisms by which the cardiac output of an animal's heart can be adjusted? Which is more important for increasing cardiac output in mammals and which is more important in fishes?

change how fast heart pump blood (heart rate) and how much blood pump through in each cardiac cycle (stroke volume). Mammals w/ heart rate, fish cardiac output

examples chemosensory, mechanosensory, and, electromagnectic sensory cells?

chemoreceptor: bind 2 protein receptor on membrane. smell and taste mechanosensory: deformations physical in membrane by touch, stretch, pressure, motion, sound. skin receptor for touch electromagnetic sensory: electrical, magnetic, light stimuli. photoreceptors in vision.

ATP hydrolysis allows for what component of skeletal muscle contraction?

cocking of the myosin head to its high-energy position

Water levels are adjusted to meet the osmoregulatory needs of the organism in the _____ of the nephron under the control of _____, also called vasopressin.

collecting ducts; antidiuretic hormone

Compare and contrast the roles of rod cells and cone cells in the retina

cone cell: color sensitive pigment, detect color rod cell: diff shape, sense light (blue green), greater number of them, detect shades of gray, see in low light

A condition called "hypoxia" occurs when not enough oxygen is being delivered to the body. In this example, what is acting as the effector? A. Heart B. Brainstem C. Motor neuron D. Diaphragm

d

The force that a muscle fiber produces results from many thousands of myosin cross-bridges binding to actin filaments over time. Given this, which statement(s) are correct. Choose all that apply. A) The net force produced by the fiber represents the summation of cross-bridge forces across the thickness and length of sarcomeres within the muscle fiber. B) More cross-bridges are associated with greater force generated by the sarcomere. C) Variation in cross-bridge force could be assessed by measuring the standard deviation of peak individual cross-bridge forces. D) All of the answer options are correct.

d The data from the graph and follow-up experiments show that cross-bridges determine muscle force. So, this information can be used to quantify cross-bridges within the length and width of a muscle fiber. In addition, variation in cross-bridges could be measured by evaluating the peak individual cross-bridge forces.

An individual with vitamin D deficiency will experience:

difficulty absorbing sufficient amounts of calcium from their diet.

The _____ is the first section of the small intestine, where food enters from the stomach.

duodenum

Which of the statements about bird respiration is true? A) It takes four ventilation cycles for a single breath of air to move through a bird's respiratory system. B) Air flowing through the air channels in the lungs moves in a tidal fashion. C) Bird lungs receive fresh air only during inhalation D) .Oxygen is exchanged between the air, the bloodstream in the lungs, and the air sacs. E) The unidirectional flow of air through a bird's lungs maintains a larger concentration gradient for diffusion than can be obtained through tidal breathing.

e

State a hypothesis that explains why all animals have chemoreceptors.

enable 2 find food source

One of the roles of the kidneys is to help buffer body fluids, to keep fluids from becoming too acidic or too basic. The cells of the renal tubule wall secrete H+ into the tubule lumen and absorb bicarbonate, passing it into the tissue fluid. Consider the reaction catalyzed by the enzyme carbonic anhydrase, shown in the accompanying figure. During heavy exercise, the reaction shifts to the right in the renal tubule cell of the nephron. t or f:

false Carbon dioxide from the renal tubule lumen moves into renal tubule cells. Increased amounts of carbon dioxide in the cells shift the reaction to the left

How do animals gain and lose water and electrolytes?

get it through drink water, freshwater fish through gill , water from cellular respiration lost through urine, feces, lung evaporation, sweating, specialize glands can remove electrolytes

Muscle contractions have _____ force at slower shortening velocities compared to higher shortening velocities.

greater/increased

The force generated by a long muscle varies as it contracts through its range of movement. At which point is the greatest force generated?

in the middle of the contraction when the muscle is at an intermediate length

Increased osmolarity of body fluids__________ ADH secretion A. Increases B. Decreases C. Has no effect on

increases (there's a diagram)

The researchers' experimental hypothesis was that changes in actin and myosin overlap would alter the number of myosin cross-bridges that could form within a sarcomere, and specifically that:

increases in overlap favor more cross-bridges to form, increasing muscle force. The researchers hypothesized that changes in overlap between myosin and actin filaments affect the number of cross-bridges and, therefore, the force a muscle can produce.

What generates the pressure changes needed to draw air into the lungs and to expel air out of the lungs

inhalation inc thoraic cavity volume, exhale relax diaphragam and dec volume thoraic cavity. cause positive pressure, expel air from lung

Which two structural features favor diffusion

large SA, short distance

When an individual has an energy surplus, he or she stores the extra energy as:

lipids

Why do mammals convert ammonia to urea rather than simply excreting it, as fishes do?

much less toxic, urea can b concentrated and stored b4 elimination

he cells that make up skeletal muscles are called:

muscle fibers

thick filaments are made of ____________ and thin filaments are made of ____________.

myosin; actin

Consider two chambers of equal volumes. The chambers are separated by a selectively permeable membrane that only allows water through. bigger fewer molecules on left, smaller more moelcules on right which way water move

net movement to right

In an antagonistic muscle pair:

one muscle undergoes flexion, whereas the other undergoes extension

Insects possess _____ circulatory systems, circulatory systems in which hemolymph completely "bathes" the organs and is not typically contained in distinct arteries or veins

open

Name two animals that are osmoconformers and two animals that are osmoregulators. What is the difference between the two types of animals?

osmoconfomrer: maintain similar solute concentration as outside. sharks, sea star osmoregulator: diff solute concentration as outside. freshwater fish, human

What drives the filtration that occurs in animal excretory systems?

pressure

After leaving Bowman's space, the filtrate, which contains electrolytes and wastes such as urea, enters:

proximal convoluted tubule

The random thermal motion of molecules results in movement from a region of higher concentration to a region of lower concentration, and this is called diffusion. The rate of diffusion across a barrier is defined by Fick's law of diffusion:Rate of diffusion = k X A X (C2 - C1) Lk = diffusion coefficient, which depends on solubility and temperatureA = surface area for exchangeC2 - C1 = difference in partial pressure of gas on either side of the barrierL = thickness of the barrier to diffusionConsider the structure and function of respiratory membranes. Respiratory membranes 1 and 2 represent membrane barriers between the outside medium and the inside of the organism. Which would have the higher rate of diffusion, respiratory membrane 1 or respiratory membrane 2? 1= straight line 2= squiggly

respiratory membrane 2 The larger the surface area to volume ratio, the faster the rate of diffusion across the surface.

What are sensory receptors?

sensory neurons or cells that are able to respond to environmental stimuli

The conversion of physical or chemical stimuli into nerve impulses is known as:

sensory transduction

What is a muscle fiber?

single cell of a muscle

We breathe more quickly and deeply when we exercise. Why does this make sense? Select all that apply. A) Because when we exercise, we consume more CO2 and must increase ventilation to supply the CO2. B) Because when we exercise, we produce more CO2 and increased ventilation is necessary to rid ourselves of CO2. C) Because when we exercise, we use more ATP, and additional O2 is necessary to generate sufficient ATP. D) Because when we exercise, we hydrolyze more ATP to ADP and Pi, and O2 is necessary for the hydrolysis, so we increase our intake of oxygen.

BC

During certain stressful moments, some individuals will begin to hyperventilate—that is, their breathing will be very shallow and quick. A by-product of hyperventilation is much lower levels of CO2 in the blood. Which effect would you also expect to find? Select all that apply.

decreased stimulation of chemoreceptors in the brainstem increased blood pH, greater than 7.2

Decreasing the amount of solute leaving the proximal convoluted tubule: (effect on water)

decreases the amount of water leaving the descending limb of the loop of Henle. The amount of water leaving the descending limb of the loop of Henle is related to solute concentration entering the loop of Henle. If there is a reduced amount of solute leaving the proximal convoluted tubule, then the concentration gradient is lower between the descending limb of the loop of Henle and the interstitial fluid. As a result, less water leaves the descending limb of the loop of Henle and enters the interstitial fluid.

A solution of water and dissolved ions is separated by a selectively permeable membrane that allows the passage of water but not small ions. The concentration of sodium is higher on one side of the membrane than on the other side. However, there is no net movement of water across the membrane. How is this possible?

depend on total solute concentration; may b other solutes that have diff concentratoin

What is the sequence of events that occurs when an action potential arrives at a muscle fiber's motor endplate, causing the muscle to be depolarized?

depolarization @ molar endplate of muscle --> propagate from cell surface to SR in cytoplasm. Ca + ion bind to troponin, make conformational change, cause tropomysoin to move, expose myosin bind site, allow it to bind

In the context of nutrition, what does "essential" mean?

essential mean can only b obtained through diet. ; essential that nutrient is absorbed

All cells of the body contain Na+/K+ pumps in their cell membranes. The Na+/K+ pumps function to:

establish concentration gradients—higher Na+ outside and higher K+ inside the cell.

t or f: Imagine that a doctor encounters a patient carrying a mutation that reduces collagen production. As a result, the arteries of this patient will likely be stronger and more resistant to aneurysms compared to arteries in an individual not carrying this mutation

f

t or f: In mammals, bulk flow only refers to the movement of oxygen (either into or out of the lungs and within the bloodstream). Bulk flow never refers to the movement of carbon dioxide.

f

tor f: the affinity of hemoglobin for O2 has decreased. A shift to the right would mean that at higher partial pressures of oxygen less oxygen is bound to hemoglobin. This reflects a decreased affinity for oxygen because the percent saturation is lower even at higher partial pressures of oxygen.

f

t or f: You turn on a light so you can get a glass of water. BEFORE you turn on the light, the Effector Enzyme is activated.

f effector enzyme turn cGMP into GMP when bound to G protein thing (g protein bound to rhodopsin), and close the Na+ channel

Mark A for True or B for False In a muscle affected by Botox, myosin will be primarily bound to ATP

f, no calcium release from SR, stuck in stage where connect to ADP and Pi

Glutamate is the neurotransmitter released at the rod-bipolar cell synapse. When there is light, the rod membrane potential will ____________ due to _________ of cations through the channel.

hyperpolarize; exit (bc K+ channel still open, so K+ leave)

Why are you unstable when you try to walk after you spin in place or take a ride on a merry-go-round?

hair cell in semicircular canal accomodate new motion. stop spin, hair cell detect chain in motion of head (relative to motion while head was spin), and lead to sense of imbalance

Which of the following is a common feature of the lateral line of fish, and statocysts of crustaceans and mammals?

hair cells w/ stereocilia

Osmoregulators _____ internal solute concentrations compared to their external environment.

have different

Bisphosphoglyceric acid (BPG) is a byproduct of glycolysis released into the bloodstream when an animal's supply of oxygen is low. Like protons, it decreases hemoglobin's affinity for O2. The effect of high BPG levels would be that:

hemoglobin releases more of its bound O2 than it would without BPG. BPG causes the same response as increased proton concentrations. BPG would cause the affinity of hemoglobin to oxygen to decrease and shift the oxygen binding curve to the right. This results in release of more oxygen at the tissues.

A sample of muscle tissue shows large-diameter fibers that are white in color. Which characteristic would also be associated with this tissue?

high rates of ATP hydrolysis Muscle fibers can increase in diameter due to increased training. The change in diameter is caused by increases in myosin and actin within each muscle fiber. High rates of ATP hydrolysis are indicative of fast-twitch muscle. ATP hydrolysis is responsible for returning the myosin head back to its relaxed state, where it is ready to bind actin and generate the power stroke. The faster ATP is hydrolyzed, the faster another cross-bridge cycle, and sarcomere shortening, can occur.

How does the tracheal respiratory system of insects enable high metabolic rates?

highly branched, v close proximity to all body cell, rapid o2 diffuse direclty to cell , no respiratory or circulatory sys

Which part of the digestive tract is the predominant location for water and mineral absorption?

hindgut

You turn on a light so you can get a glass of water. BEFORE you turn on the light, your bipolar cells are __________________.

hyperpolarized

Which of these organisms would be able to extract the greatest percentage of oxygen from their respiratory medium

salmon

What is the basic contracting unit of a skeletal muscle?

sarcomere

Functional unit of skeletal muscles are called:

sarcomeres

The kangaroo rat is a desert mammal that conserves water by producing highly concentrated urine (urine very low in water). You compare the relative lengths of the loops of Henle in the kangaroo rat with those from a mouse species native to a temperate area where water is readily available. You find that the loops of Henle are relatively

shorter in the mouse

Compare the force produced by a muscle over time when it is stimulated by a single twitch stimulus with the force produced by multiple stimuli at low frequency, and then with the force produced when the stimulation frequency is increased.

single twitch little force. multi twitch low freq is still little force bc muscle fully relax b/w stimuli. if no time to relax, freq summ together and sustain contract muscle: tetanus

Bowman's capsule acts as a filter that allows:

small molecules to enter the proximal convoluted tubule.

Where does the cycle start?!? When a muscle is completely relaxed (no contraction is occurring), at which point is the cycle paused?

B, when myosin is bound to ADP and Pi, ready to bound to actin but cant

Diagram the four basic steps of O2 transport from an animal's respiratory medium (air or water) to its cells.

1) ventilation o2 air to lung 2) diffusion, o2 lung to blood 3) circulation o2 blood lung to tissue 4) O2 blood to cell

Consider the events in muscle contraction. 1. ATP binds to myosin head. 2. Myosin head interacts with actin. 3. ATP is converted to ADP and Pi. 4. Myosin head is cocked back. 5. Myosin head pivots in the power stroke. 6. ADP and Pi are released from myosin. Place the following events in muscle contraction in the correct sequence from first to last.

1, 3, 4, 2, 6, 5

Describe parts of a simple reflex circuit.

1. Particular tendon is activated (physician strikes tendon with hammer) 2. Stretch receptor in extensor muscle responds by sending signal along sensory nerve 3. Sensory neuron synapses with motor neuron in spinal cord 4. Motor neuron sends excitatory signal to . same extensor muscle, which responds by contracting 5. An inhibitory interneuron inhibits contraction of opposing flexor muscle Need to inhibit other because muscles can only contract and not pull or push When one muscle is activated the other is inhibited => flexor stimulated, extensor inhibited when bringing your hand/knee towards body, revered if bring away from body Goes from Afferent fiber (sensor) to spine (interneuron) inhibits extensor/inhibitor efferent neuron and stimulates other extensor/inhibitor efferent neuron (motor neuron) => cannot be activated at same time because do different actions in same pathway tetanus => This toxin is a poison that blocks the nerve signals from your spinal cord to your muscles. This can lead to severe muscle spasms, muscle contraction of sustained force

In the ascending limb of the loop of Henle, urea is concentrated within the loop because: A) the loop of Henle is impermeable to urea. B) All of these choices are correct. C) the ascending limb pumps electrolytes into the interstitial fluid. D)water moves out of the descending limb by osmosis

B, Urea is concentrated as the filtrate moves through the renal tubules because electrolytes are pumped out of the filtrate and into the interstitial fluid in the ascending limb of the loop of Henle, water moves out of the descending limb of the loop of Henle by osmosis, and the renal tubules are impermeable to urea.

Based on the Results and Follow-up Work sections, which statement is correct? select few (A) Researchers found experimental support for their hypothesis that muscle force depends on the overlap of actin and myosin filaments allowing cross-bridge formation within a sarcomere. (B) Researchers found experimental support that muscles change length when they contract through shortening of myosin filaments. (c)Researchers found experimental support that muscles change length by the relative sliding of adjacent actin and myosin filaments. (D) Researchers found no support for their experimental hypothesis.

A and C The researchers found support for their hypothesis that muscle force depends on the overlap between actin and myosin. These data and the follow-up work support the hypothesis that muscle length changes when actin and myosin slide relative to each other.

In the figure shown, panel a depicts a photoreceptor and its postsynaptic cell in the dark and panel b depicts both cells in the light. What causes the change observed in this figure? photoreceptor is rod cell i think A) Hyperpolarization of the rod cell in the light inhibits release of a neurotransmitter. B) Hyperpolarization of the rod cell in the dark causes release of a neurotransmitter. C) This figure is incorrect; dark and light are reversed. D) Depolarization of the rod cell in the light inhibits release of neurotransmitter.

A, Rod cells release neurotransmitter in the dark. When light hits a rod, there is a conformational change in retinal that causes a change in membrane potential, and it hyperpolarizes. This reduces the amount of neurotransmitter released and changes the signals sent to the postsynaptic cell.

Decreased Na+ in body fluids (Na+ depletion) __________ renin secretion A. Increases B. Decreases C. Has no effect on

A; look at diagram

An increase of _____ increases the permeability of the collecting duct to water.

ADH (antidiuretic hormone)

What is the role of ADH in the regulation of urine concentration?

ADH inc urine concentration by inc permeability of collecting duct to water. in presence, aquaporin inserted into collecting duct lining cell , concentarte urine. in absense, impermeable to water, so urine is dilute

What is the sequence of events involved in the cross-bridge cycle? How do these events explain how muscles generate force and shorten when they are stimulated to contract?

ADP + Pi bound myosin head it binds to actin binding site & crossbridge. then release it, cause head pivot towards sarcomere midline, powerstroek and move actin filament relative to thick filament. sarcomere short. then bind new ATP, release, hydrolyze to ADP and Pi which cause head to cock back and begin new cross bridge cycle

Curare is a paralyzing compound that blocks the action of the neurotransmitter acetylcholine at the muscle fiber's motor endplate. What effect does curare have on the release of calcium ions from the sarcoplasmic reticulum of the muscle cell?

Ach block, can'tdepolarizem embrane, so Ca not released from SR, muscle can't contract

What is meant by tidal ventilation?

Air moves into the lungs during inhalation and air moves out of the lungs during exhalation.

Consider the figure below. Mark A for True or B for False. The cells around region B use more ATP than those in region G. B is descending loop of henle, G is distal convoluting tube

B

If a hair cell bends toward the kinocilium... A. It generates action potentials B. It releases neurotransmitters C. Both A and B D. Neither A nor B

B

Mark A for True or B for False Calcium is necessary for repolarization in the heart

B, false. Ca move into cell, so doesn't repolarize it.

Cats and other nocturnal predators have a greater number of rod cells in their eyes compared to cone cells. What would you predict about the color vision of cats?

Because of the decreased number of cone cells, cats have (relatively) poor color vision. Nocturnal organisms need to be able to see in low light conditions. The more rods they have, the more cells they have in their eyes that are specific for sensing light intensity differences because they all have the same opsin. Color vision is not as important for nocturnal organisms as it is for diurnal organisms, and the higher number of cones in diurnal organisms results in their having fewer rods.

Describe the properties of blood and blood vessels.

Blood is comprised ofred bloods cells (45%): Transport oxygen and help transport carbon dioxide White blood cell (~1%): fight infection plasma (55%): water (solvent for carrying other substances), has ions for osmotic balance and pH balance, and transport substances in blood Blood travels through blood vessels (gas exchange requires narrow vessels, but this creates a lot of resistance => so have blood transported over larger distances in relatively few large diameter vessels with low resistance => capillaries take up resistance by having many of them and help make time for diffusion to occur) Arteries - transports blood Away from the heart to the body or lungs (high pressure and made of collagen and elastin to withstand high pressure => pulmonary artery (towards heart from lung) and aortic valve (biggest artery, sends oxygenated blood to body) Arterioles - branches of arteries with smaller diameter Capillaries - branches of arterioles with even smaller diameter (one red blood cell thick) => where gasses are exchanged by diffusion with surrounding cells Veins - transports blood toward the heart from the body or lungs (low pressure), return blood towards the heart => vena cavae (largest vein, drains blood from body and head into heart), pulmonary vein (oxygenated blood from lung to heart)

Which statement would result in tetanus? A) stimulating a muscle fiber to contract immediately after it has relaxed B) stimulating a muscle fiber to contract when it has partially relaxed C) stimulating the muscle fiber so frequently that it cannot relax at all D) allowing a muscle fiber to relax for several seconds between twitches

C; Tetanus occurs when multiple depolarizing stimuli reach the muscle cell at regular intervals. Each of the stimuli are summed over time and there is no overall relaxation of the muscle in between stimuli. The summation of stimuli results in sustained contraction of the muscle

Why is calcium necessary for muscle contraction?

Calcium is needed to activate troponin so that tropomyosin can be moved to expose the myosin-binding sites on the actin filament. Myosin heads must bind to the actin filaments in order for the cross-bridge cycle to occur. At rest in the sarcomere, tropomyosin covers the myosin-binding sites of actin. When calcium binds to troponin there is a change in conformation such that tropomyosin moves and the myosin-binding sites are exposed along the actin filaments. Without this change, cross-bridge formation could not occur.

Discuss the various functions of the cells, proteins, and other components found in human blood.

Composed primarily of Plasma and Cellular elements Plasma is made of:Water => solvent for carrying other substancesIons (for cardiac action potentials, contractions, etc to be made possible). Plasma Proteins (fibrinogen- clots, pH buffering, defense) Substances transported by blood (hormones, nutrients, waste, O2 and CO2) Cellular elements include:red blood cells- transport oxygen and help transport CO2 Leukocytes(white blood cells)- help with defense and immunity Platelets- assist in blood clotting.Stuff necessary for cell function

ou take a human smooth muscle cell and block the release of calcium from the sarcoplasmic reticulum. What effect does that have on contraction of that smooth muscle cell, and why?

Contraction still occurs because Ca2+ can enter the cell directly through Ca2+ channels in the plasma membrane and bind to calmodulin. Although a large amount of calcium is sequestered in the sarcoplasmic reticulum, any calcium that enters the cell can bind troponin causing contraction of smooth muscle tissue. The amount of calcium that comes in through calcium channels will be lower than that released from the sarcoplasmic reticulum, but slower, smaller contractions can still occur.

extra about countercurrent flow

Countercurrent exchange - two fluids flow in opposite directions and exchange properties. (hot → cold, cold → hot), (High O2 conc → low O conc, vice versa) Myoglobin - another oxygen carrier, that has a higher binding affinity to oxygen and holds onto to it more tightly (acts as more of an O2 storage that delivers O2 to cells when hemoglobin gets depleted) MAKE SURE TO CHECK pH REASONING! HIGH H+ CONC = LOW pH

Suppose the stereocilia of one hair cell become permanently bent. What will most likely happen as a consequence? A. A single pitch will be constantly perceived B. A single pitch will no longer be perceivable C. A or B depending on the hair cell's location D. A or B depending on the bending's direction

D

Which of the following correctly represents the order in which blood flows through structures of the heart? A. Right ventricle, left atrium, pulmonary artery B. Left atrium, pulmonary artery, right atrium C. Pulmonary artery, aorta, left ventricle D. Superior vena cava, pulmonary vein, aorta

D

Which of the statements about the protonephridia of freshwater flatworms is accurate? A) The fluid passing through the tubules is not modified before excretion B) .Protonephridia are surrounded by a capillary network to allow for selective reabsorption and secretion. C) The urine leaving the body of a freshwater flatworm is more concentrated than its body fluids. D) Fluid from the body enters the protonephridia without first being filtered. E) Muscular contractions drive fluid movement through the excretory tubules.

D

Relate the events during the cardiac cycle to those represented on an ECG.

Depolarization= contraction Repolarization= Relaxation At P → SA node activated → action potential fires → atria (depolarization) contracts → atria empties → ventricles fill (actively) Before QRS (delay) => The delay in transmission from the AV node and through the conducting fibers ensures that the ventricles do not contract until they are fully filled with blood from the atriaAV node activated → fires action potential → travels to Bundle of His and Purkinje fibers (takes time) QRS =>Atria repolarize + relax + refill and Ventricles (depolarize) contract → Ventricles empty. Depolarization of the ventricles- ejection of the blood from the heart and into the arteries - beginning of the systole - first heart sound - repolarization of the atria ST segment- where ventricular repolarization begins- atria are filling again - maintain contraction of to make sure all blood in ventricles expelled T => Ventricles relax and fill (passively, b/c of gravity). Ventricles repolarize and relax - repolarization of AV node Systole lasts until the T wave!!! (Ventricles are still emptying)

Predict how changes in elevation or external pressure will affect ventilation and gas exchange.

Elevation results in thinner air => lower partial pressure => less oxygen attach to hemoglobin Higher external pressure (sea level) => more partial pressure, easier to breath Less external pressure (elevation) => harder to breath There needs to be a balance

Compare and contrast the structure and function of slow-twitch versus fasttwitch muscles

Fast twitch muscle fibers:produce a lot of force, gets fatigued easily- olympic sprinterUse glycolysis for ATP production contract quickly and consume lots of ATPRely heavily on glycolysis to produce ATPLess myoglobin => look whiteThe larger fast-twitch fibers take a shorter time to reach peak force and can generate higher amounts of force than slow-twitch fibers. Fast-twitch fibers can generate more force, but are quicker to fatigue when compared to slow-twitch fibers Slow-twitch - contract slowly and consume less ATP (greater resistance to fatigue) -- olympic marathoner Have mitochondria to supply ATP to muscle fibers by aerobic respiration Have a lot of myoglobin => look Red Because they can provide their own source of energy, slow-twitch fibers can sustain force for an extended period of time, but they are not able to generate a significant amount of force. Slow-twitch fibers have a low activation threshold, meaning they are the first recruited when a muscle contracts. If they can't generate the amount of force necessary for the specific activity, the fast-twitch muscle fibers are engaged. Ex: The tonic muscles responsible for maintaining posture have a higher density of slow-twitch fibers. Steady-state endurance training can help increase mitochondrial density, which improves the efficiency of how the body uses oxygen to produce ATP

Discuss the role of enzymes and other secreted molecules throughout the process of digestion

Fats in the duodenum secrete CCK which makes the gall bladder release Bile to break down fats Stomach acid in the duodenum secretes secretin which influences the pancreas to secrete bicarbonate to neutralize it Gastrin is secreted to stimulate secretion of gastric juices => lower pH Amylase: breaks down carbohydrates => found at neutral pH => found in mouth and small intestine (amylase produced by pancreas) Lipase: breaks down fats/lipids => mouth (tongue lipase), stomach lipase, and small intestine (pancreatic lipase) Pepsin: breaks down protein => works at low pH (made by hydrochloric acid and gastrin) => found in stomach were most protein breakdown occurs Trypsin: enzyme produced by pancreas that breaks down proteinsS Secretin: hormone released by cells lining duodenum in response to acidic pH of stomach contents entering small intestine and stimulates pancreas to secrete bicarbonate ions bile: produced by liver and stored in gallbladder, aid in fat digestion by breaking large clusters of fats into smaller lipid droplets CCK: peptide hormone senses fat content and causes gallbladder to contract => releasing bile into duodem

Describe how hair cells function to transduce mechanical signals to the brain

Hair cells have stereocilia that project from the surface that move in response to vibrations and cause an opening or closing of ion channels => ability to balance and hear. While they do not fire action potentials themselves, the depolarization causes a release of neurotransmitters that alter the firing rate of adjacent neurons.Sense of motion => the vestibular system is made up of two statocyst chambers and three semicircular canals. Hair cells are located within the semicircular canals and provide a sense of gravity and angular motion because as the head rotates, the fluid in the canals causes the stereocilia to move and therefore activate sensory neurons. Ability to hear => hair cells affect our ability to hear by converting pressure waves into an electrical impulse that is sent to brain. Sound is received by outer ear => sent to eardrum => amplified by 3 middle ear bones (larger size of eardrum compared to oval window)=> vibrations of oval window cause fluid pressure waves in basilar membrane and cochlear duct => cochlear duct contains organ of corti with stereocilia supported by the basilar membrane but projected into tectorial membrane. Vibrations cause movement of basilar membrane which bends stereocilia because they are projected into unmoving tectorial membrane. When stereocilia bend against tectorial membrane it causes depolarization and release of neurotransmitters. When stereocilia bend in opposite direction, hair cells repolarize and do not release neurotransmitters

Describe how hemoglobin binds oxygen and how this relates to gas exchange

Hemoglobin - protein in red blood cells that binds to oxygen B/c oxygen becomes bound to hemoglobin, the pO2 in the red blood cell is lower than the pO2 in the plasma, so O2 keeps diffusing into the cell As blood pO2 rises, O2 saturation of hemoglobin rises as well in a sigmoidal fashion, b/c the binding affinity of hemoglobin increases as it binds more O2 (cooperative binding) -Increase in binding affinity with additional binding of O2) Small increase in O2 lead to a large increase in hemoglobin oxygen saturation (bound to 4 O2 molecules) As active cells consume O2, they reduce local pO2 of cell to 40 mmHg or less => lower pO2, hemoglobin has steep slope => indicates relatively small decrease in pO2 allows for large amounts of O2 can be released by cell Right => Low binding affinity means increased release of O2 into body tissue cells => increase dissociation => this also means that large amounts of O2 can be released from hemoglobin when needed by cells Left => Higher binding affinity => hold more O2 at lower pO2 => hard to dissociate, because need a larger decrease in pO2 to release O2, why we use hemoglobin instead Saturation curve can move depending on pH, CO2 levels Moves left if: lower CO2, higher pH, lower temp Moves right if: higher CO2, lower pH, higher temp Ex. The saturation curve is dependent on pH levels (Exercise → increased aerobic respiration → increased CO2 from tissue → increased proton conc → decreased pH → lower saturation levels (b/c more oxygen is delivered to cells) Bohr effect => when pH falls (more H+ ions) during exercise => affinity of hemoglobin for O2 decreases (moves right) => because binding affinity reduced, more O2 released and supplied to cells for Aerobic ATP synthesis This can also happen with an increase in CO2, which decreases pH and caused hemoglobin to have lower binding affinity

Predict how water will move if the osmolarity of cells or body fluids is altered.

High osmolarity= decrease in water concentration. This means that the kidneys will want to increase the amount of reabsorption of water to prevent dehydration. This means that the water will passively diffuse out of the loop of henle. Urine becomes more concentrated at higher osmolarities because water is moving out. Increase/high osmolarity => water move down concentration gradient, increase ADH Low osmolarity= increase in water concentration. This means the H20 will want to be secreted so that there isn't overhydration. (ex. The ascending loop of henle is not permeable to water because it has decreasing amounts of osmolarity. It is during that time that Na and Cl are being reabsorbed.When Na and Cl are being reabsorbed, the urine becomes less concentrated. This part of the loop of henle is not permeable to water so only Na and Cl can be reabsorbed. Low osmolarity => water dilution, decrease ADH

Predict how altering the release of hormones or digestive enzymes will affect digestive processes such as the break down and absorption of nutrients

If secretin not released => very acidic in duodenum from stomach and enzymes cannot work if bile not released because does not release CCK => cannot break down fats No gastrin => cannot make pH in stomach lower for peptide to work pH might be too low or high restricting enzymes from working

Predict how changes in a sensory pathway will affect sensory perception.

If you affect one part of the pathway (cut off hearing nerve), anything that doesn't allow pathway to connect to the sensory nerve that sends signal to the brain will cause there to be no perception of the stimulus

Predict how photoreceptors change in response to light exposure

In photoreceptors of the retina there are opsin molecules arranged in plasma membrane that contain a light-absorbing pigment called retinal. When retinal absorbs a photon of light it undergoes a conformational change from cis-retinal to trans-retinal. Rod and cone cells have leaky Na+ channels that let Na+ ions in even at rest and release the neurotransmitter glutamate. However, when cis-retinal changes to trans-retinal the Na+ channels close, causing the membrane to become hyperpolarized and thus reduce the release of glutamate. The reduction of glutamate triggers ESPNs and ISPN, affecting the firing rate of neurons, which in turn provides information about location and intensity of light to the brain. The photoreceptors synapse to bipolar cells, which receive their input and, in response, also release neurotransmitters. The bipolar cells synapse to ganglion cells, which activate and then transmit action potentials by the optic nerve to the visual cortex Rods and Cones - Hyperpolarize in response to light, but DO NOT fire action potentials. Instead they synapse with bipolar cells which modulates their release of neurotransmitters Light <= Depolarize (ganglion cells) <= depolarize (bipolar cells) <= Hyperpolarize (cones/rods) No light <= Hyperpolarize (ganglion cells) <= Hyperpolarize (bipolar cells) <= Depolarize (cones/rods)

What is the function of the vasa recta?

It maintains the concentration gradient established by the loop of Henle.

Describe the structure and function of a neuromuscular junction

It's a synapse between a motor neuron and a muscle, where the neurotransmitter isacetylcholine => Its function is to cause muscle contraction when activated Consists of a motor neuron synapsing with muscle fiber. There are various channels that will open/close to let in certain ions. The results is the release of neurotransmitters (Ach) that depolarize muscle cell (opens Na+ channels) and allows SrR to release calcium, which binds to troponin and removes tropomyosin from actin so myosin can undergo cross-bridge cycle1. Action potential reaches synaptic terminal → change in voltage 2. Voltage gated calcium channels open and calcium flows in 3. Calcium binds to vesicles with neurotransmitter acetylcholine, vesicles fuse with membrane → exocytose acetylcholine 4. Acetylcholine binds to the ligand-gated ion channels in muscle cell 5. Potassium flows out and sodium flows in → Na+ channels open => depolarization → action potential 6. Depolarization causes voltage-gated sodium channels to open 7. More sodium comes in 8. Action potential propagates down T-tubules → calcium released from sarcoplasmic reticulum 9. SR release Ca2+, which bind to troponin in thin filament (actin), which moves tropomyosin from the binding sites of myosin 10. Exposure of myosin-binding sites on actin allows cross-bridge as myosin (thick filament) can now attach to produce shortening of muscle (contraction) 11. After AP, Ca2+ moves back to SR and tropomyosin covers actin again, after contraction ends and muscle relaxes

Relate the structure of skeletal muscle to its function in generating a contractile force.

Larger muscles with more fibers produce greater forces Muscle force is depending on state already in Whole muscles are made up of parallel bundles of individual muscle fibers. A muscle fiber is a muscle cell that uses ATP => Each muscle fiber in turn contain hundreds of long, rodlike structures called myofibrils. Myofibrils contain parallel arrays of actin and myosin filaments that cause a muscle to contract (where sarcomere is found) => Sarcomeres which are relatively constant invertebrates(size) are arranged in a series along the length of the myofibril. It is the contractile functional unit of muscles. The region from one Z disc to the next is sarcomere. Actin subunits: Think filament (double helix with troponin and tropomyosin), lie more on the outside of the sarcomere Myosin: Thick filament, lie in the center of the sarcomere The thick and thin filaments slide with respect to one another, using ATP as a source of energy. As a result of the sliding, the Z discs are pulled closer together (shortening results from sliding of actin thin filaments relative to myosin thick filaments) => cause contraction The contraction of a whole muscle fiber results from the simultaneous contraction of all of its sarcomeres => When Ca++ is present, this cycling of cross bridges continues and the filaments continue to slide with respect to one another. When Ca++ goes back into the sarcoplasmic reticulum, the contraction stops Striated muscles are arranged into muscle bundles → muscle fibers (muscle cell) → myofibrils (rod-like structure that contains parallel arrays of myosin and actin filaments) Myofibrils have rows are actin and myosin that are broken up by z-discs in units called sarcomeresSliding Filament ModelSarcomere length contracts when muscle contracts → more overlap of myosin and actin filaments

Relate changes in ion movement to the cardiac action potential.

Longer than normal action potentialSodium channels open → Sodium channels close → Calcium channels open and fast potassium channels close → Calcium channels close and slow potassium channels open → Resting potential → Fires again 0: Na+ is rushing into the cell to make the membrane potential more positive to fire an action potential => depolarization (triggers contraction/systole of ventricles) 1: the membrane decreases its permeability to the Na+ because the Na+ channels close. 2. On the plateau that corresponds to 2, the Ca+ channels open at the same time as the K= channels close fast. This is the downtime that the ventricles needs to fill with blood before contracting again (systole) => still depolarized 3: the Ca2+ channels are closing and the K= channels are opening slowly which causes a repolarization (membrane potential becoming more negative) => relaxation (diastole) 4: resting membrane potential (k+ ions are leaving)

Evaluate oxygen-hemoglobin binding graphs to predict the percent oxygen saturation of different globin proteins under varying conditions of PO2, pH, etc.

Lower PH => rightward shift --> less binding affinity to release O2 more readily to cellsHigher CO2 => rightward shift Leftward shift => Higher O2 affinity, lower CO2, higher pH, lower temperatureRightward shift => Reduced O2 affinity, higher CO2, lower pH, higher temperature Look at which part of the cycle they want you to find, look for the right pH (there will be a decrease in pH due to heavy exercise => rightward shift), then use the graph and pO2 given to O2 saturation (iclicker)

Describe the process of digestion as food moves through the stomach, duodenum, and small intestine

Mouth - Mechanical and start of chemical breakdown - food mixed with amylase - enzyme that breaks down carbohydrates and lipase which breaks down lipids => works at a neutral pH Stomach - main sites of protein and lipid breakdown - largely protein breakdown - gastric hormone stimulate secretion of gastric juices => lower pH - Chief cells secrete pepsinogen (in its inactive form it is secreted so it does not digest itself) => activated to pepsin by low pH made by HCl-> made by low pH by parietal cells making HCl (hydrochloric acid) - these two come together to make active pepsin which breaks down proteins into amino acids - Made acidic by break down of CO2 and H2O into protons that move across membrane by K+/H+ ATPase and Cl- goes straight across both membranes to make HCl Small intestine - Digestion of protein, fats, and carbohydrates in duodenum (first part of small intestine) and absorption of nutrients - Duodenum increases release of secretin which makes pancreas release bicarbonate which neutralizes pH - Pancreas also produces: Lipase - break down fats, Amylase - breaks down carbohydrates, Trypsin - breaks down proteins- - Fats in duodenum stimulate release of CCK which stimulates gallbladder to produce bile that emulsifies fats - breaks down large clusters of fat into smaller lipid droplets - Jejunum and ileum - rest of small intestine where absorption takes place - absorbed across microvilli surfaces - more neutral pH => so enzymes from mouth renature Large intestine- Water and inorganic ions absorbed

Describe how and where different nutrients are absorbed.

Nutrients => glucose, protein, and lipids absorbed in small intestine and water and inorganic ions in large intestine - because products of fat digestion are lipid soluble they do not require a carrier protein for transport => readily diffuse from lumen into cells glucose and protein enter lumen of small intestine and use co-tansporters driven by Na+ going down its concentration gradient => Na+ concentration is kept low inside the cell by action of the Na+-K+ pump Glucose exists the intestinal cell passively by a glucose transport protein

Define the terms osmolarity, tonicity, hypertonic, hypotonic, and isotonic

Osmolarity: concentration of solute compared to the total amount of solutei.e lower osmolarity = less solutes Higher osmolarity = more solutes Osmosis: Movement of water from lower to high solute concentration Tonicity: state of solution in terms of osmotic pressure (state of solution) Hypertonic: higher solute concentration and lower water concentration (than another solution) ==> water will flow in Hypertonic: lower solute concentration and higher water concentration (than another solution) => water move out isotonic - same solute concentration and water concentration (as another solution) => no net flow of water

A researcher is comparing the size of sarcomeres in mice to those in elephants. What will he find?

Sarcomere size is relatively constant in vertebrates. As a result, mouse and elephant sarcomeres will likely be equal in size. Muscle anatomy is conserved across vertebrates. The size of actin and myosin filaments are approximately the same in vertebrates. Because actin and myosin length are conserved, the length of the sarcomere is relatively constant in vertebrates as well.

If solution X has a 2% concentration of salt (NaCl) and solution Y has an 8% concentration of NaCl, which of the statements is correct?

Solution X is hypotonic relative to solution Y.

Identify critical cells involved in auditory and visual sensory transmission to the brain.

Terms in this set (49) OriginalAlphabetical Identify critical cells involved in auditory and visual sensory transmission to the brain Auditory:Hair cells: specialized mechanoreceptors that sense movement and vibrationHair cells that detect sound vibrations are found in the cochlea and those that are part of the vestibular system that sense gravity and motion are found in the semicircular canals Stereocilia: hair-like projections from surface of hair cell that move in response to vibration => their motion cause depolarization of the cell's membrane by opening or closing ion channelsDespite their name, Stereocilia more similar to microvilli than to cilia bc cilia can move on their own but Stereocilia cannot hair cells do not fire action potentials but they release neurotransmitters which affect the firing rate of adjacent neurons when they're depolarized Visual:Opsin: light-sensitive protein that converts light energy into electrical signals in receptor cell => They are G protein-coupled receptors, meaning they activate G proteins which leads to a cellular response with Opsin, the cellular response is a change in membrane potentialCone cells: photoreceptor cells that contains opsins sensitive to different wavelengths of light => provide the sharpest vision, color, found in foveaRod cells: sensitive to light but most sensitive to blue-green light (gray shades) => found in peripheryBipolar cells: receive input from rod and cone cells and releasing neurotransmitters (do NOT fire action potentials) Ganglion cells: located on front of retina and receive input from bipolar cells => If activated, ganglion cells transmit action potentials by the optic nerve to the visual cortex in the brain to begin processing images Rods,Cones, and Bipolar cells generate graded potentials while ganglia cells generate the action potentials

Describe the structure and function of the mammalian kidney.

The cells of the kidneys are surrounded by a solution called the interstitial fluid Functional unit of the kidney is the nephron Concentration of solutes increases as you move down => most concentrated interstitial fluid at base of kidney Filtrate - fluid inside of nephron The glomerulus is a tuft of capillaries that filters the waste in the blood to make the filtrate (where filtration occurs) proximal convoluted tubule - the first portion of the renal tubule from which electrolytes and other nutrients are reabsorbed into the blood => reabsorbs all the glucose and amino acids filtered by the glomerulus, as well as most sodium and chloride ions (Reabsorption) Loop of Henle - the middle portion of the vertebrate renal tubule, which creates a concentration gradient that allows water passing through the collecting duct to be reabsorbed (Reabsorption) Distal convoluted tubule - the third portion of the renal tubule, in which urea is the principal solute and into which other wastes from the bloodstream are secreted (Secretion => active process) => (change blood pressure (increase salt and water retention) Collecting duct - where water levels are adjusted to meet the osmoregulatory needs of the organism and therefore maintain homeostasis (can be permeable to water depending on ADH)

Fish in a marine environment must maintain a relatively constant ion concentration in their tissues and blood. How do the chloride cells in the gills aid fish in the removal of excess ions?

The chloride cells actively remove ions from the body and water follows by osmosis.

In systemic tissue fluids, the enzyme carbonic anhydrase catalyzes the reaction CO2 + H2O → H2CO3 (which then can dissociate into H+ and HCO3-). In fact, CO2 released from cells is converted to HCO3- ions and travels in that form in the bloodstream. HCO3- is reconverted to CO2 + H2O in the pulmonary capillaries by the same enzyme, and there the CO2 is exhaled. How is it possible for the same enzyme to catalyze reverse reactions?

The direction of a reversible reaction is influenced by the concentrations of reactants and products. In pulmonary circulation, the low CO2 concentration favors the formation of CO2 and H2O. The direction of a reversible reaction is influenced by the concentrations of reactants and products. In pulmonary circulation, the low CO2 concentration favors the formation of CO2 and H2O.

You turn on a light so you can get a glass of water. At the moment the light turns ON, the Sodium (Na+ ) enters the cell. A. True B. False

b

Imagine that a young girl suffers a horseback riding injury and one of her ribs punctures her diaphragm. How will this injury affect the girl's breathing?

The injury will make it more difficult to increase negative air pressure in her chest cavity, making inhalation more difficult. Contraction of the diaphragm expands the thoracic cavity, creates negative pressure, and aids the movement of air into the lungs. Relaxation causes the diaphragm to move up under the lungs and helps with exhalation.

Consider the mammalian heart. Why is the muscular wall of the left ventricle thicker than that of the right ventricle?

The left ventricle must contract with more force in order to send blood to the body's extremities. The right ventricle only needs to push blood through the pulmonary arteries to the lungs. The distance to the lungs from the heart is very short, so a large amount of pressure is not needed. Because the pressure necessary to get blood to the lungs is low, the muscular wall of the right ventricle does not need to be as thick as the left ventricle that must generate enough pressure to push blood throughout the body.

Aging can sometimes lead to an increase in the stiffness at the base of the basilar membrane. What effect would this have on a person's hearing?

The person would lose the ability to hear high-pitched sounds. The frequency of sound waves determines pitch—the more frequent the waves, the higher the pitch, and vice versa. As sound waves travel through the fluid of the inner ear, they move the basilar membrane. If the basilar membrane becomes stiff, it is less affected by the movement of that fluid. This reduces the amount of movement in structures attached to the basilar membrane, such as hair cells and stereocilia. Because the stereocilia will not move as much, there is a decrease in stimulation of the mechanoreceptors on these cells, which makes sounds more difficult to detect.

You turn on a light so you can get a glass of water. At the moment the light turns ON, the amount of neurotransmitters released by your rods and cones ________. A. Increases B. Decreases C. Does not change

b

Explain how sensory information is encoded in action potentials

The strength of a signal received by a sensory receptor neuron is indicated by the rate that it fires action potentials. For example in the case of touch, stronger pressure results in higher firing rates in the sensory receptor neuron. Over time, the receptor's rate of firing declines as it becomes "familiar" with the signal. This process is known as accommodation. The location of the signal's source is often determined using lateral inhibition. In this case, pressure at one spot not only stimulates local sensory receptor neurons but also inhibits adjacent interneurons. As the location of the stimulus changes, the location with the strongest receptor signaling also shifts. Lateral inhibition enhances the level of contrast between region of receptors that is being stimulated and surrounding regions that are not. Without lateral inhibition the accuracy of locating the stimulus would be reduced.

Explain how the processes of vision and hearing occur

Vision, involves a complicated process of converting light signals into images in the brain. Light passes through the lens, where it is focused, to the retina where photoreceptors called rods and cones convert the information to electrical impulses that can be interpreted by the brain. Rod/Cone cell detect light, Rod/Cone cells stop sending neurotransmitters to bipolar cells, which in turn begin to release neurotransmitters, causing ganglion cells to fire off action potentials that signal the visual cortex in the brain. (as release of glutamate closes cation channel of bipolar cells, which causes it to become hyperpolarized) Hearing, sound funnels into the ear canal and causes the eardrum to move. Soundvibrations move through the ossicles to the cochlea. Sound vibrations cause thefluid in the cochlea to move.The auditory nerve sends signals to the brain wherethey are interpreted as sounds. Sound waves travels through auditory canal, eventually hitting tympanic membrane. The membrane vibrates, causing the 3 middle ear bones to vibrate. The last bone hits the oval window that moves the fluid in the cochlea. The hair in the cochlea bend one way or another depolarizing/hyperpolaizing and release neurotransmitters that cause an action potential in later cells that send a signal to auditory cortex.

Relate water and ion movement through the nephron

Water movement => passive transport through the nephron, it is usually excreted back into functioning tissueIon movement = active transport Water usually moves by osmosis (passive) in the descending limb of loop of Henle (could be on the line down (collecting duct) if increase ADH) Ions/waste/nutrients => move through active transport at proximal convoluted tubule, descending limb, and distal convoluted tube

Differentiate between passive and active transport as filtrate moves through the nephron

Water usually moves by osmosis (passive) in the descending limb of loop of Henle (could be on the line down (collecting duct) if increase ADH) => water moves down concentration gradient due to concentration gradient made by loop of henle Ions/waste/nutrients => move through active transport at proximal convoluted tubule, descending limb, and distal convoluted tube => active transport move against concentration gradient and need ATP => most active transport when things are being reabsorbed

You turn on a light so you can get a glass of water. At the moment the light turns ON, the concentration of cGMP inside your rods and cones ________. A. Increases B. Decreases C. Does not change

b

A competitive track star at UCLA is training for an upcoming meet. In the first 50 m of the 800 m race, which muscle fiber type is the runner using? A. Fast-twitch muscle fibers B. Slow-twitch muscle fibers

a

A condition called "hypoxia" occurs when not enough oxygen is being delivered to the body. When body senses hypoxic conditions, the rate of ventilation will ... A. Increase B. Decrease C. Not change

a

A red blood cell has just left the right ventricle of the heart. It travels to the lungs, back to the heart, to the liver, and then back to the heart again. At each point on its journey (A-D), determine the oxygen saturation level (%) of the hemoglobin molecules found in this red blood cell. (You may assume the pH of the blood is 7.4.) A B D C What is the approximate O2 saturation at point D? A. 75% B. 30% C. 40% D. 10% E. None of the above

a

Black widow spider venom causes explosive release of ACh. At the site of a black widow spider bite, muscle membrane potential will __________. A. Become more positive B. Become more negative C. Not change

a

Carbonic anhydrase inhibitors are commonly prescribed to treat glaucoma. A side effect could be ___________ in stomach pH. A. An increase B. A decrease C. No change

a

Consider the figure below. Around point F, the extracellular fluid surrounding the nephron is _______ compared to the fluid in the lumen of the nephron. A. Hypertonic B. Hypotonic C. Isotonic its the collecti g ducts

a

Cutting the auditory nerve could treat the symptoms of: A. Tinnitus (Meniere's disease) only B. Auditory hallucinations (epilepsy) only C. Neither D. Both

a

Depolarization and repolarization... sounds like we're talking about action potentials. Do muscles have action potentials? A.Totally! B.No way! C.How should I know

a

During a typical cardiac cycle, the atria of the heart contract ______ the ventricles contract. A. Before B. After C. At the same time as

a

In the dark your rod cells are releasing neurotransmitter on to the bipolar cells. In the dark, your bipolar cells are _________. A. Hyperpolarized B. Depolarized

a

Mark A for True or B for False In a muscle affected by Botox, tropomyosin will be bound to actin

a

Sensory transduction requires: A) All of these choices are correct. B) reaction of a receptor protein with a stimulus. C) alteration of the conformation of a channel protein. D) a change in membrane potential.

a

What function does the low pH of the stomach serve? A) All of these choices are correct. B) It allows for the activation of pepsinogen into pepsin. C) It allows gastric enzymes to work. D) The acidic conditions break down foods directly.

a

When stomach acid reaches the duodenum, it triggers the release of bicarbonate ions, which increase the pH of the duodenum. This is an example of: A. Negative feedback B. Positive feedback C. Neither; this is not a feedback system

a

Which of the following allows the semicircular canals in humans to provide a sense of balance and body position? A) the deflection of stereocilia in hair cells of the semicircular canals due to changes in position of the head B) nerve impulses generated based on changes in the density of the gel that surrounds the hair cells in the semicircular canals C) floating statocysts within the gel of the semicircular canals acting to deflect the hair cells when the head changes position

a

You turn on a light so you can get a glass of water. At the moment the light turns ON, your retinal ganglion cells will _____firing action potentials. A. Start B. Stop C. None of the above. (retinal ganglion cells do not fire action potentials)

a

Fish deal with similar issues. If a saltwater fish were unable to regulate chloride - what would happen? A. The fish would swell with water. B. Nothing, sodium would still be secreted. C. The fish would find fresh water to live. D. The fish would loose water and shrivel up

a Reduced sodium/chloride (salt) excretion will make the fish more concentrated inside reducing the osmotic flow of water out of the body. Would this happen in fresh water fish?

Organophosphates inhibit the activity of the enzyme acetylcholinesterase (AChE). Exposure to organophosphates will therefore __________ muscle stimulation by motor neurons. A.Increase B.Decrease C.Not change

a (it can't breakdown AcH, so stuck in synpase --> always)

Consider the figure below. Mark A for True or B for False. The osmolarity of tissue fluids surrounding the nephron is higher at point D (ascending, lower limb of henle) than point G (distol convoluting tubule)

a ; At point D, the extracellular fluid surrounding the nephron is about 1000 miliosmoles. At point G, the extracellular fluid is about 300 miliosmoles. How can you tell from your handout?. osmolarity dec as go down nephron

Which of the statements about the control of blood volume and blood pressure is false? A) Angiotensin II stimulates the release of antidiuretic hormone, which increases salt and water uptake by the distal convoluted tubule. B) Angiotensin II causes the smooth muscle in the walls of the arterioles to contract. C) A drop in blood pressure stimulates the cells of the juxtaglomerular apparatus to release renin. D) Inactive angiotensinogen is converted to angiotensin II by an enzyme released from the lungs.

a Angiotensin II is a vasoconstrictor, so it helps to increase blood pressure. Angiotensin II also stimulates the release of aldosterone from the adrenal cortex. Aldosterone causes an increase in sodium reabsorption by the kidneys, causing increased water retention and an increase in blood volume.

Mark A for True or B for False The pulmonary vein carries deoxygenated blood.

b. Arteries carry blood away from the heart and veins carry blood back to the heart. The pulmonary vein carries oxygenated blood from the pulmonary circuit back to the heart.

Usain Bolt, a world champion sprinter, can run a 10-meter split in 0.82 seconds. Say you obtain a quadriceps muscle sample from Usain Bolt and compare it to one from a 25-year-old male long-distance runner. What differences do you expect to observe between those two muscle samples? Select all that apply. A) more fast-twitch fibers in Usain Bolt's leg muscles B) red and white muscle fibers of larger cross-sectional area in Usain Bolt's leg muscles C) more mitochondria in Usain Bolt's leg muscles

a b

As fluid moves through a vessel, which factors determine the flow resistance? Select all that apply. A) the length of the vessel B) the viscosity of the fluid C) the pressure exerted by the heart D) the radius of the vessel

a b d

Which of the choices is/are secretions produced by the pancreas? Select all that apply. A) bicarbonate ions to neutralize stomach acid B) methane from fermentation C) trypsin for further protein digestion D) lipase for fat digestion E) gastrin to stimulate HCl production

a c d

Which of the following is referred to as the power stroke?

a conformational change in myosin

What are desirable characteristics for a gas exchange surface, such as the endothelial cells lining the inside of a lung? Select all that apply.

a large surface areaa thickness under 10 micrometers

Tetanus is:

a muscle contraction of sustained force resulting from repeated action potentials.

What senses do the three semicircular canals in the mammalian inner ear provide?

a sense of angular motion and balance

What would you predict to be the effect on an animal species of having longer loops of Henle in their kidney structure? A) They would be better able to survive in desert or dry habitats than animals with shorter loops. B) They can produce less concentrated urine (one with a higher concentration of water). C) They can reabsorb more water, glucose, and amino acids in the ascending limb. D) They can produce greater concentration gradients of electrolytes in the deep medulla of the kidney.

a, d

At the beginning of ventricular diastole, blood pressure in atria is _______ blood pressure in the ventricles A. Higher than B. Lower than C. The same as D. No way to know!

a; Blood flows down pressure gradients from high to low pressure

The lungs are highly branched. What is the primary purpose of this branching? A. It increases the surface area of the lungs B. It increases the volume of the lungs C. A and B are correct D. None of the above

a; greater SA the more diffusion occur

A person's blood pressure falls. Which of the answer choices would you expect to occur? Select all that apply. A) Water uptake by the distal convoluted tubule will increase. B) Circulating concentrations of renin will increase. C) Circulating concentrations of aldosterone will decrease. D) Circulating concentrations of angiotensin II will decrease.

ab

Sensory cells and sensory neurons allow multicellular animals to sense physical and chemical cues from their environment. What key properties of these cells enable them to perform this function? Select all that apply. A) Sensory cells and sensory neurons have protein receptors linked to intracellular or membrane-based signaling pathways that alter ion channel permeability. B) Sensory cells and sensory neurons have electrically excitable membranes that change in charge potential in response to binding an environmental signaling molecule. C) All sensory cells and sensory neurons fire action potentials when they bind a signaling molecule. D) Sensory neurons have myelinated dendrites that serve as nerve endings.

ab

The force generated by a muscle depends on: Select all that apply. A) the degree of overlap between actin and myosin in the sarcomeres B) the number of sarcomeres contracting C) .the amount of ATP available D) .the number of cross bridges between actin and myosin in the sarcomeres.

abcd

Signals from the sympathetic nervous system cause arteriole B to constrict. Arteriole B is most likely carrying blood to ________. (Hint: fight or flight) A.The brain B.The small intestine C.A leg muscle D.The heart

b Remember: Sympathetic = Fight or Flight Parasympathetic = Rest and Digest

Glucose transport out of intestinal cells into the bloodstream requires which of the following? Select all that apply.The general chemical nature of a hormone can be used to predict: A) a glucose channel protein on the cell surface facing the blood B) a Na+ concentration gradient between the blood and the intestinal cell C) a Na+ channel connecting the intestinal cell to the blood stream D) a higher concentration of glucose in the intestinal cells E) a Na+-glucose cotransporter in the membrane facing the blood

ad

What are two differences in the physical properties of water and of air that affect gas exchange in aquatic animals

aquatic animal need efficient extract o2 from water bc less than air. also water viscouse and dense, so need to use more E to move bulk flow

Although the exact cause of Meniere's Disease remains a mystery, which of the following could most reasonably be caused by a build up of excessive endolymph fluid? A. Auditory canal becomes blocked B. Hair cell function is altered C. Stapes can no longer vibrate D. Tympanic membrane is ruptured

b

Antacids like pepto-bismal are commonly taken to increase the pH of the stomach. If you take an antacid with your meal, _____ secretin will be released by your duodenum compared with eating an identical meal without an antacid. A. More B. Less C. An equivalent amount of

b

At high altitudes, the partial pressure of oxygen is ______ the partial pressure of oxygen at sea level. A. Higher than B. Lower than C. The same as

b

During a typical cardiac cycle, cell depolarization triggers muscle _______ and repolarization triggers muscle ________. A. Contraction; contraction B. Contraction; relaxation C. Relaxation; contraction D. Relaxation; relaxation

b

How does blood pH at muscle tissue compare to blood pH at the lungs? Leaves the body A.Blood pH is higher at the muscle B.Blood pH is lower at the muscle C.Blood pH is the same at the muscle

b

Mark A for True or B for False In a muscle affected by Botox, Ca2+ channels in the SR will be mostly open

b

One of the effects of the hormone secretin is to stimulate the release of bicarbonate ions into the duodenum, which neutralizes the acid that enters the duodenum with food from the stomach. One consequence of neutralizing the pH in the intestine is that: A) enzymes that catalyze the hydrolysis of carbohydrates are denatured B) .enzymes that catalyze the hydrolysis of carbohydrates are active. C) carbohydrates are not as easily broken down in this neutral environment. D) the enzymatically catalyzed hydrolysis of carbohydrates that began in the stomach is halted in the duodenum.

b

When a hair cell stereocilia bend away from the kinocilium, A) it releases neurotransmitters. B) it does not release neurotransmitters. C) it generates an action potential to communicate with the auditory nerve. D) voltage-gated calcium channels open when the membrane potential of the hair cell increases.

b

When the diaphragm contracts, the volume of the lungs _____ and the pressure in the lungs ______ A. Increases; increases B. Increases; decreases C. Decreases; increases D. Decreases; decreases

b

Which of the statements is false? A) Nutrient absorption takes place primarily in the jejunum and ileum. B) As food passes through the liver, it is mixed with bile, which breaks large clusters of fats into smaller droplets. C) The hormone cholecystokinin stimulates the release of bile from the gall bladder D) .Lipases in the small intestine break lipids into glycerol and free fatty acids.

b

Which of these choices increase(s) the amount of oxygen that a fish can extract from the surrounding seawater? A) very thin lamellae B) All of these choices are correct.v C) Ventilation of the gills with the aid of an operculum D) countercurrent exchange E) gills with a large surface area

b

If the partial pressure of oxygen outside of a cell is 100 mmHg and the partial pressure of oxygen inside of a cell is 25 mmHg, which of the statements is correct? A) There will be no net diffusion of oxygen in either direction. B)There will be a net diffusion of oxygen from outside the cell to inside the cell C) There will be a net diffusion of carbon dioxide into the cell. D) There will be a net diffusion of oxygen from inside the cell to outside the cell. E) There will be a net diffusion of carbon dioxide out of the cell.

b; Gases will move from areas of higher partial pressure to areas of lower partial pressure for that gas. The partial pressure of oxygen is higher outside the cell, so oxygen will move into the cell.

A climber is scaling Mt. Everest. As the elevation increases, the average amount of oxygen bound to the hemoglobin in their red blood cells ________. A. Increases B. Decreases C. Does not change

b; PO2 decrease

If carbonic anhydrase stopped working, the amount of oxygen delivered to systemic tissues would _________. A. Increase B. Decrease C. Not change

b; less Co2, so pH doesn't decrease, so less O2 dropped off

What are the similarities and differences between foregut and hindgut fermentation?

both rely on bacteria to break down plant material into nutrient absorb. foregut maximize nutrient absorb by process it before reach small intestine. hindgut first small intestine before feremented by bacteria residing in colon and cecum, reduce host animal extarct nutrient

Which of these events occurs during systole?

both ventricle contract

Draw a mammalian nephron, label and describe the primary function of each part, and show the direction of water and electrolytes in each part.

bowman capsule: blood filtration proximal convoluted tubule: reabsorb solute descending loop of Henle: reabsorb water ascending loop of henle: reabsorb electrolytes distal convoluted tubule: secretion of waste collecting duct: regulation of urine concentartion

How are sound vibrations amplified in a vertebrate ear?

by movement of the tympanic membrane, the bones in the middle ear, and the fluid-filled region covered by the oval window. The tympanic membrane vibrates when the soundwave strikes its surface. The tympanic membrane's vibrations are transmitted to the inner ear bones, which then vibrate and send the sound waves across the oval window into the fluid-filled cochlea. Each time the waves are transmitted they are amplified.

Meniere's Disease is linked to an excessive volume of endolymph fluid. Where in the ear is endolymph found? A. Outer ear B. Middle ear C. Inner ear D. B and C E. A, B, and C

c

On a space station, without gravity, the function of which system(s) is(are) least affected? A) the two statocyst chambers of the vestibular canal B) The statocyst chambers and the semicircular canals are equally affected C) the semicircular canals

c

Secretin stimulates the release of bicarbonate ions into the duodenum, which neutralizes acidic chyme from the stomach. One consequence of neutralizing the pH in the intestine is that: A. Carbohydrates are not as easily broken down in this neutral environment B. Enzymes that catalyze the breakdown of carbohydrates are denatured C. Enzymes that catalyze the breakdown of carbohydrates are active D. The enzymatically catalyzed breakdown of carbohydrates that began in the stomach is halted in the duodenum

c

The motility of the digestive tract and secretion of digestive enzymes are optimized for digestion and absorption. For most nutrients, once material is in the digestive tract, the digestive system does not vary its rate of absorption according to body needs. A. This is an example of a homeostatic positive feedback mechanism B. This is an example of a homeostatic negative feedback mechanism C. This response is not homeostatic

c

When do the atria repolarize? A. P wave B. PR segment C. QRS complex D. ST segment E. T wave

c

Which is not a feature shared by statocysts of some animals and vestibular systems of mammal? a) They are both fluid-filled organs lined by hair cells. B) They both have hair cells that form synapses with sensory neurons. C) They both have small particles in the fluid-filled chamber that depress the stereocilia of the hair cells. D) They both allow the animal to determine its orientation in space.

c

Which statement is an accurate comparison of fast-twitch and slow-twitch fibers? A) Slow-twitch fibers have fewer mitochondria than fast-twitch fibers. B) Fast-twitch fibers generate more force per unit cross-sectional area than slow-twitch fibers. C) Most skeletal muscles consist of mixtures of fast- and slow-twitch fibers. D) Fast-twitch fibers appear red, whereas slow-twitch fibers appear white.

c

You add a toxin that prevents the Na+ /K+ pump from hydrolyzing ATP. Absorption of which nutrient(s) will be affected? A. Glucose only B. Amino acids only C. Both glucose and amino acids D. Neither will be affected

c

You turn on a light so you can get a glass of water. At the moment the light turns ON, your bipolar cells will ______ firing action potentials A. Start B. Stop C. None of the above. (Bipolar cells do not fire Action potentials)

c

You wake up in the middle of the night. As you look around the dark room, your pupils ________ to let in ________ light. A. Constrict; more B. Constrict; less C. Dilate; more D. Dilate; less

c

At high altitudes, the percentage of oxygen is ___________ the percentage of oxygen at sea level. A. Higher than B. Lower than C. The same as

c Sea level O2 is 21% Total Pressure = 760 mm/Hg Partial pressure of oxygen is 160 mm/Hg At 10,000 feet O2 is 21% Total Pressure = 523 mm/Hg Partial pressure of oxygen 110 mm/Hg

Which roles are played by calcium ions in coordinating the activation of a muscle by motor neurons? Select all that apply. A) Calcium ions diffuse into the sarcoplasmic reticulum to open actin binding sites for myosin, leading to force generation. B) Calcium ions enter the motor endplate of the muscle fiber, causing depolarization of the muscle cell. C) Calcium ions are actively pumped into the sarcoplasmic reticulum to cause muscle relaxation by allowing tropomyosin to block actin binding sites. D) Calcium ions are released from the sarcoplasmic reticulum and bind with troponin to open actin binding sites for myosin, leading to force generation. E) Calcium ions enter the motor neuron axon terminus to stimulate vesicle fusion and neurotransmitter release into the neuromuscular synapse.

c d e

What does the ST interval represent? A. The heart is relaxing B. The ventricles are filling C. The atria are filling

c. ventricles r still emptying kinda, they repolarize during the T wave

Refer to the figure shown. The transduction of sound waves to changes in membrane potential takes place: A) within the tectorial membrane as it is stimulated by the hair cells. B) in the oval window, which vibrates at the same frequency as the original sound. C) when stereocilia bend against the tectorial membrane, causing hair cell depolarization. D) in the basilar membrane as it vibrates at different locations. E) as the vibrations received by the outer ear cause the eardrum to vibrate

c; The basilar membrane is in contact with the fluid inside the ear that transmits sound waves. As the fluid moves, it causes the basilar membrane to move. The movement of the basilar membrane causes the stereocilia to move up (or down) and bend against the tectorial membrane. When there is contact with the tectorial membrane, the mechanoreceptors on the stereocilia depolarize and the signal is sent through the auditory nerve to the brain.

In which of the groups of vertebrates listed below would you expect to find the fewest number of different photopigments? canines humans birds

canines

An essential amino acid is defined as one that:

cannot be synthesized by an organism's cellular biochemical pathways

Predict the effect of toxins or genetic mutations on the function of skeletal muscles.

cannot release ACh => no muscle contraction no calcium => cannot send message so no contraction receptor antagonist of ACh => no muscle contraction

Diffusion of materials between the blood and body tissues occurs at which of the blood vessels?

capillaries

Salivary amylase starts the chemical digestion of:

carbohydrates in the mouth

Which change in vessel shape most affects resistance to blood flow

change in vessel radius; 2x reduct radius inc resistance up to 16x

Animals that survive in very dry habitats will likely have a more _________ as a result of the _________steps of the excretory process.

concentrated urine; reabsorption and secretion

The system diagrammed is an example of _________ flow and is _________ efficient than _________ flow. arrow in same direction

concurrent; less; countercurrent

Why can you lift a larger load when your elbow is slightly flexed and your biceps muscle is at an intermediate length than you can when your elbow is fully extended?

contract intermediate length maximize actin & myosin overlap, allow greater # cross bridge form, and more force produce

The system diagrammed is an example of _________ flow and is _________ efficient than _________ flow. arrow in opp direction

countercurrent; more; concurrent

Based on the diagram shown here, ______ concentration in the duodenum is homeostatically regulated. A. Bicarbonate B. Bile C. CCK D. H+ ion E. Secretin

d

During an auditory hallucination, sound is perceived without an auditory stimulus. Based on what you learned about the brain last week, stimulation in which lobe of the brain would be most likely to generate an auditory hallucination? A. Frontal lobe B. Occipital lobe C. Parietal lobe D. Temporal lobe

d

Which of the statements about gastrin is false? A) Gastrin is produced by cells lining the stomach. B) A low pH in the stomach inhibits the secretion of gastrin. C) Gastrin stimulates the production of HCl. D) Gastrin secretion is initiated in response to the sight or smell of food.

d

The data plotted in both graphs show that: A) force is minimal at both short muscle lengths and long muscle lengths. B) force is maximal at an intermediate muscle length, which corresponds to maximal actin-myosin overlap within the sarcomere. C) at long lengths, actin thin filaments are pulled out beyond their overlap with myosin thick filaments so that few, if any, myosin cross-bridges can form. D) All of the answer options are correct.

d Force is maximal at an intermediate length of muscle. Force is minimal for both very short and very long muscle lengths. At long lengths, actin thin filaments are pulled out beyond their overlap with myosin thick filaments, so that few if any myosin cross-bridges can form. At short lengths, adjacent actin filaments within a sarcomere interfere with each other and thick filaments run into the Z-disc, disrupting the number of myosin cross-bridges that can form.

Two solutions of water with dissolved potassium and glucose are separated by a selectively permeable membrane that only permits the passage of water. If the two solutions have the same total solute concentration, but solution 1 has a higher concentration of potassium and a lower concentration of glucose than solution 2, which of the statements is correct? A) There will be net potassium movement from solution 1 to solution 2. B) There will be net water movement from solution 2 to solution 1. C) There will be net water movement from solution 1 to solution 2. D) There will be no net movement of water molecules between the solutions.

d Water does not discriminate between the concentrations of specific solutes on either side, but only moves in respect to total solute concentration in one compartment as compared to another. Because the solute concentrations are the same on both sides of the membrane, there would be no net movement of water.

In the proximal convoluted tubule, which of the following molecules is being secreted? A. Sodium B. Potassium C. Glucose D. Urea E. All of the above

d its secretion!!

t or f: Assume that blood pressure drops in a person because of an injury, and given the drop in blood pressure, indicate whether the statement on the body's responses is true or false. Circulating levels of renin will decrease.

false When blood pressure decreases, the juxtaglomerular apparatus releases renin. Renin converts angiotensinogen to angiotensin I. ACE (angiotensin converting enzyme) from the lungs converts angiotensin I to angiotensin II. The presence of angiotensin II causes the release of aldosterone from the adrenal glands and stimulates the distal convoluted tubule to take up more salt and water. The increased uptake of salt and water increases blood volume and blood pressure.

t or f: Assume that blood pressure drops in a person because of an injury, and given the drop in blood pressure, indicate whether the statement on the body's responses is true or false.Water absorption by the distal convoluted tubule will decrease.

false When blood pressure decreases, the juxtaglomerular apparatus releases renin. Renin converts angiotensinogen to angiotensin I. ACE (angiotensin converting enzyme) from the lungs converts angiotensin I to angiotensin II. The presence of angiotensin II causes the release of aldosterone from the adrenal glands and stimulates the distal convoluted tubule to take up more salt and water. The increased uptake of salt and water increases blood volume and blood pressure.

Consider the figure shown of an electrocardiogram (EKG) trace and the typical action potential of cells in the left ventricle. Indicate whether the statement is true or false.Ventricular diastole occurs at the interval labeled 2 on the action potential figure. interval 2 is plateau

false; only interval 3 after when the Ap starts to fall is when repolarization and thus diastole occurs

Which of these processes occur within Bowman's capsule?

filtration

What are the three steps in which animals excrete wastes

filtration (create filtrate), reabsorption, secretion

Diagram the path of blood flow through the heart, lungs, and body of a fish and of a mammal or bird.

fish: like a loop basically mammal: separate lung & systemic capilalry

When skeletal muscles contract such that bone segments move closer together, this action is known as:

flexion

During _____ bone segments move closer together, whereas during ______ bone segments move further apart.

flexion; extension

Which of these animals has a heart in which oxygenated and deoxygenated blood mix?

frog

What are two features of the gills of aquatic animals that favor diffusion of O2 and CO2?

gills=stacks of lamellae, each have thin layer flattened epithelial cell. large SA 4 gas exchange & short distance for diffusion

Which of the answer choices correctly describes the path taken by excretory fluid through the mammalian kidney?

glomerulus, capsule, renal tubules, collecting ducts, ureter, bladder

Signal molecules are responsible for regulating the allocation of resources in the body in response of times of stress. What is the approximate percent O2 saturation of hemoglobin in blood vessels returning from liver cells when the concentration of glucagon in the blood is high versus low?

glucagon high= low pH and low pOH. 7.2, maybe 20 mmHg? glucagon low= regular, around 40 mmHg coming back from liver and 7.4 pH

Muscle, fat, and glycogen are all reservoirs of energy. In which order are they used during a prolonged fast?

glycogen, fat, muscle protein

You discover a new type of marine organism that has the kidneys of a fish but no gills. Based on what you know about other aquatic organisms, the newly discovered organism is _____ compared to the surrounding water.

hypotonic This organism likely produces ammonia as its nitrogenous waste. This requires a lot of water for excretion. Because the fish is hypotonic, it will constantly take on water from its environment. The kidneys are able to produce copious amounts of dilute urine quickly to deal with the constant absorption of water.

What happens when a cell is placed in a hypotonic solution (one with a solute concentration lower than that of the cell)? What happens when a cell is placed in a hypertonic solution (one with a solute concentration higher than that of a cell)?

hypotonic: water move into cell and swell/burst hypertonic: water move out of cell and shrivel

During heavy exercise, the pO2 in muscle may drop to 20 mmHg. Considering the oxygen-hemoglobin dissociation curve shown, what is the approximate percent O2 saturation of hemoglobin in venous blood returning from skeletal muscles during heavy exercise?

idk look on graph

How do the kidneys help to regulate blood volume and blood pressure?

if BP drop, cells in juxtaglomerular apparatus release renin into blood. this renin leads to activation of angiotensin II, which cause Blood vessel to constrict , and inc BP. angiotension II also cause release of aldosterone, which trigger reabsorp water and electrolytes into distal convoluted tube and collecting duct, leading to inc in BV and BP

What stimulates a skeletal muscle cell to contract?=

impulse from motor neuron

What are two mechanisms by which the force of contraction can be increased in vertebrate muscles?

inc freq stimulation muscle by motor neuron (inc firing freq), or activate greater # motor neuron to recruit more motor units (more muscle fiber)

Signals from the sympathetic nervous system cause arteriole B to constrict. As a result, the amount of blood flowing through the other three arterioles will ____________.

increase

Evaluate the effect of hormones (e.g., ADH and aldosterone) and drugs on the function of the kidney

increase ADH (dehydrated)/ high osmolarity => more permeable to water => concentrated urine Less ADH (well-hydrated)/ low osmolarity => less permeable => dilute urine Diuretic (alcohol) => decrease ADH => promote urine dilution => net loss of water => dehydrated Aldosterone => secreted by adrenal gland, increases blood pressure by increasing blood volume, increase salt and water uptake by distal convoluted tubule If aldosterone levels decrease the reabsorption of electrolytes and water back into the blood decreases and therefore blood pressure will decrease

As water leaves the descending limb of the loop of Henle, the solute concentration of the filtrate:

increases

You turn on a light so you can get a glass of water. At the moment the light turns ON, the amount of GTP bound to the Gα subunit of trimeric G proteins __________.

increases

Sometimes while traveling, people are infected with a protist parasite, Giardia. One of the side effects of Giardia infection is diarrhea. When someone has diarrhea, they lose excessive water and salt from the body. The result is loss of Na+, dehydration that leads to decreased extracellular volume and plasma volume, and decreased arterial blood pressure. Given this, the vasopressin secretion of a person infected with Giardia:

increases. When a person has diarrhea, they fail to reabsorb ions from the small intestine, and fluids entering the large intestine have high solute concentrations. This keeps higher volumes of water in the large intestine. In order to compensate for water loss through the digestive system, vasopressin is released. The presence of vasopressin increases the permeability of the collecting ducts to water, so water is returned to the interstitial fluid. This decreases the amount of water lost through urination.

What percentage of oxygen in the air is typically extracted by the mammalian lung when an animal is resting?

less than 25%

The filtrate is dilute at the start and the end of the loop of Henle. What, then, is the function of the loop of Henle?

loop creates concentration gradient from cortex to medulla , important for subsequent water reabsorption in collecting duct. loops also leave urea as main solute

What type of sensory receptor is a hair cell?

mechanoreceptor

Diagram a generalized sensory receptor cell and show how it changes its firing rate in response to a stimulus

more freq firing, open channel on dendrite

A single motor neuron and the population of muscle fibers that it innervates is called a(n):

motor unit

water moves out of the collecting ducts and into the interstitial fluid by:

osmosis. Water moves out of the collecting ducts by osmosis, driven by the difference in solute concentration between the fluid in the collecting ducts and interstitial fluid. In this way, urine is concentrated without ever needing to actively pump water.

Which of the relationships best describes the partial pressure of oxygen (pO2) in the lung (alveolar air), red blood cells, and blood plasma?

pO2 red blood cell < pO2 blood plasma < pO2 lung

What drives the reabsorption that occurs in animal excretory systems?

passive diffusion for some substances and active transport for others

Which process is responsible for creating most of an animal's nitrogenous waste?

protein breakdown during metabolism

What are the main sites of digestion of protein, carbohydrates, and fats, and which enzymes are involved in breaking down each of these?

protein: stomach, pepsin, further digested by trypsin in small intestine carbs: mouth where salivary amylase (sugar/starch), small intestine by pancreatic amylase fats: mouth, stomach, small intestine, by lingual, gastric, and pancreatic lipases respectively

Which structure is the opening in the eye through which light passes?

pupil

Cells of the excretory tubule _________water by osmosis, from which we can conclude that the solute concentration in these cells must be _________ than in the filtrate.

reabsorb; higher

Hair cells function by: A. firing action potentials directly. B. releasing neurotransmitters. C. stabilizing homeostasis. D. using chemosensory receptors.

releasing neurotransmitters

In general, excretory organs function to do which of the statements? Select all that apply.

remove nitrogenous wastes from the circulating blood maintain water balance in the body maintain electrolyte balance in the body

How does the branching of larger arteries into many smaller vessels affect the rate of and resistance to blood flow in the smaller vessels?

resistance to blood flow prop to 1/r^4, where r is radius. inc in resistance cause prop dec in blood flow. as artery branch into smaller vessel, radius dec

The digestive tract is well-adapted for digestion and absorption. For most nutrients, once material is in the digestive tract, the digestive system does not vary its rate of absorption according to body needs. homeostatic?

respones not homeostatic

Within the human eye, photoreceptors (rods and cones) are located within the

retina

Which structure is/are the light-absorbing compound(s) used by photoreceptors?

retinal

Cone cells most likely evolved from:

rod cell

Water moves from the descending limb of the loop of Henle to the interstitial fluid because:

solute concentration is higher in the interstitial fluid as compared to the solute concentration in the descending limb of the loop of Henle. The amount of water leaving the descending limb of the loop of Henle is related to solute concentration entering the loop of Henle. Ions are pumped out of the proximal convoluted tubule, reducing the solute concentration entering the descending limb of the loop of Henle. This creates a concentration gradient wherein solute concentration is higher in the interstitial fluid than in the descending limb of the loop of Henle. The difference in solute concentration results in water leaving the descending limb of the loop of Henle by osmosis.

Select the type of channel that is associated with ion transport in stereocilia.

stretch-gated channel Ligand-gated channels only open when a ligand binds. Voltage-gated channels only open when there is a change in membrane potential. Stereocilia are situated at a fixed distance from adjacent stereocilia. Movement of fluid in the cochlea or semicircular canals causes movement of the hair cells, bringing some stereocilia closer together but stretching others further apart. This stretching causes ion channels to open and depolarization of the sensory nerves associated with the hair cell.

In the figure shown, digestion in the small intestine is aided by secretions from the liver, gallbladder, and pancreas. Secretin, a hormone produced by cells lining the duodenum, stimulates the pancreas to release bicarbonate ions. t or f

t

t or f: Cells can regulate their internal osmotic pressure by controlling the solute concentration inside of the cell.

t

t or f: During starvation, humans and other animals deplete glycogen and fat reserves first, followed by protein.

t

t or f: In most organisms, the excretion of wastes is closely tied to the maintenance of water and electrolyte balance.

t

t or f: Metanephridia differ from protonephridia in that selective reabsorption of materials occurs via cells lining the tubules in protonephridia and via capillaries in metanephridia.

t

t or f: When the filtrate reaches the distal convoluted tubule, additional wastes are pumped from the bloodstream into the distal convoluted tubule.

t

The initiation of the mammalian heart contraction:

take place at SA node

Draw a graph of the force-shortening velocity relationship of striated muscle

tall hill from left slope down to right. shortening velocity -50% to 0 to 100%. Force on y axis; highest until right before 0, then slope down

A shift to the right in the hemoglobin dissociation curve means that:

the affinity of hemoglobin for O2 has decreased. A shift to the right would mean that at higher partial pressures of oxygen less oxygen is bound to hemoglobin. This reflects a decreased affinity for oxygen because the percent saturation is lower even at higher partial pressures of oxygen.

: in what region(s) of the nephron would you expect to find high numbers of sodium/potassium pumps?

the distal convoluting tubule

Atrioventricular valves separate:

the left atrium from the left ventricle and the right atrium from the right ventricle

Shortly after eating a candy bar, where would the increased concentration of glucose be first evident? A) the cytoplasm of the epithelial cells lining the lumen of the small intestine B) the blood flowing past the basal membrane of the epithelial cells of the lumen C) the lumen of the small intestine

the lumen of the small intestine

What would the concentration of cytoplasmic Ca2+ mostly likely look like on this graph? Relative cytoplasmic [Ca2+] is shown on each graph as an orange dashed line. The scale of the y-axis is arbitrary.

the one sustained but below tetanus; no reach same lvls as tetanus

Rods and Cones hyperpolarize in response to light. Select A or B for the image that represents your rod cells in the dark

the one with Na+ channel open and release glutamate

Maximum force is generated by a muscle contraction when:

the sarcomere is at intermediate length before contraction begins.

Images that you see in your peripheral vision are not as sharp as those directly in front of you because:

there is a higher concentration of cone cells in the center of the retina in an area called the fovea.

Sickle-cell anemia is a genetic disorder of individuals homozygous for a mutation of hemoglobin that causes their red blood cells to be sickle shaped and stiff under conditions of low pO2. Why is this disease life threatening?

trnasport of deformed blood cell hard in blood vessel. so supply O2 to tissue reduce, CO2 build up, can lead to organ fail

Calcium is necessary to initiate muscle contraction. Which molecule binds calcium?

troponin

One of the roles of the kidneys is to help buffer body fluids so that they are not too acidic or too basic. The cells of the renal tubule secrete H+ into the tubule lumen and absorb bicarbonate (HCO3-), passing it into the tissue fluid. Consider the reaction catalyzed by the enzyme carbonic anhydrase, shown in the accompanying figure During heavy exercise, the reaction shifts to the right in the tubule lumen of the nephron. t or f?

true Carbon dioxide coming from the body moves into the cells of the tubule and is converted to bicarbonate to help buffer tissue surrounding the tubules and excrete hydrogen ions. The active transport of hydrogen ions into the lumen drives the reaction to the right, with CO2 and H2O.

t or f: When compared to the leg muscles of an Olympic sprinter, the muscles of an Olympic marathoner would likely show a greater proportion of oxidative slow-twitch fibers.

true Oxidative slow-twitch fibers are important for repeated contraction in the muscle with limited fatigue. Slow-twitch muscle is characterized by higher density of myoglobin and mitochondria to fuel oxidative phosphorylation, which provides more ATP for repeated muscle contractions.

Consider the figure shown of an electrocardiogram (EKG) trace and the typical action potential of cells in the left ventricle. Indicate whether the statement is true or false.Atria are emptying at the interval labeled 4 on the action potential figure. interval 4 is after repolarization, and it's flat after the graph has fallen

true The plateau phase on the action potential figure helps inhibit tetanus in the heart. Diastole is when the heart is filling and ventricles are relaxed. Notice that the graph wave shown in the EKG figure represents ventricular contraction and systole of the cardiac cycle. At point 4 on the action potential figure, the atria are emptying into the ventricles, which are relaxed, and readying the ventricles for contraction.

t or f: Assume that blood pressure drops in a person because of an injury, and given the drop in blood pressure, indicate whether the statement on the body's responses is true or false.Circulating levels of aldosterone will increase.

true When blood pressure decreases, the juxtaglomerular apparatus releases renin. Renin converts angiotensinogen to angiotensin I. ACE (angiotensin converting enzyme) from the lungs converts angiotensin I to angiotensin II. The presence of angiotensin II causes the release of aldosterone from the adrenal glands and stimulates the distal convoluted tubule to take up more salt and water. The increased uptake of salt and water increases blood volume and blood pressure.

t or f: Assume that blood pressure drops in a person because of an injury, and given the drop in blood pressure, indicate whether the statement on the body's responses is true or false.Circulating levels of angiotensin II will increase.

true When blood pressure decreases, the juxtaglomerular apparatus releases renin. Renin converts angiotensinogen to angiotensin I. ACE (angiotensin converting enzyme) from the lungs converts angiotensin I to angiotensin II. The presence of angiotensin II causes the release of aldosterone from the adrenal glands and stimulates the distal convoluted tubule to take up more salt and water. The increased uptake of salt and water increases blood volume and blood pressure.

t or f; Assume that blood pressure drops in a person because of an injury, and given the drop in blood pressure, indicate whether the statement on the body's responses is true or false.The sympathetic nervous system stimulates the adrenal glands.

true When blood pressure decreases, the juxtaglomerular apparatus releases renin. Renin converts angiotensinogen to angiotensin I. ACE (angiotensin converting enzyme) from the lungs converts angiotensin I to angiotensin II. The presence of angiotensin II causes the release of aldosterone from the adrenal glands and stimulates the distal convoluted tubule to take up more salt and water. The increased uptake of salt and water increases blood volume and blood pressure.

v\Draw a graph of the isometric force-length relationship of striated muscle, indicating where maximal overlap between actin and myosin filaments occurs.

upside down U shape. % muscle length on x axis, % max isometric force on y

What are three forms of nitrogenous waste? How is each an adaptation for the environment in which an animal lives

urea, ammonia, uric acid. ammonia toxic, but water soluble for fish yay urea: less toxic, need E and water to excrete, mammal and other land animal uric acid: least toxic, not water soluble, good 4 desert

Most mammals excrete _____; most aquatic animals excrete _____; birds, insects, and many reptiles excrete _____.

urea; ammonia; uric acid

The figure shown is of tubes illustrating O2 uptake at the fish gill. The values shown in the tubes indicate percent fluid saturation of O2. Which answer choice identifies the fluid and the direction of flow correctly?

well water move in same direction as anterior--> posterior. water is always gonna have higher O2 concentration than blood. also, blood flow in opp countercurrent to max flow Water always has a slightly higher concentration of oxygen than the blood. Water flows over the gill lamellae in the opposite direction of blood flow in the gill lamellae. This maintains a concentration gradient where the water is always at slightly higher concentrations of oxygen than the blood, so that oxygen will move down its concentration gradient into the blood of the fish across the gill lamellae.

You measure levels of Ca2+ in various locations within a motor neuron and a skeletal muscle fiber when the motor neuron is not depolarized, and the muscle fiber is at rest. Where do you expect to find high levels of Ca2+

within the sarcoplasmic reticulum of the muscle fiber Calcium is sequestered in the sarcoplasmic reticulum until the muscle cell depolarizes.

When an animal dies, its limbs and body become stiff because its muscles go into rigor mortis (a term that means "stiffness of death"). Why would the loss of ATP following death cause this to happen?

without new ATP, myosin cross bridges formed can't detach. so remain bound and muscle stiff