Exam 3 Physiology

What are some of the advantages to a closed circulatory system?

1. More Rapid Blood Flow 2. More Efficient Transport of Wastes and Nutrients

At an atmospheric pressure of 870 mm Hg of 21% oxygen, the partial pressure of oxygen is

182 mm Hg (0.21 x 879)

The Bohr shift on the oxygen-hemoglobin dissociation curve is produced by changes in

PH

The shark rectal gland _____.

is involved in osmoregulation

Among vertebrate animals, urea

is made in the liver by combining two ammonia molecules with one carbon dioxide.

When you hold your breath, which of the following blood gas changes first leads to the urge to breathe?

rising carbon dioxide

Which of the following best describes the process of ventilation?

the movement of the respiratory medium past the respiratory surface

Urea is

the primary nitrogenous waste product of humans

The greatest difference in the concentration of respiratory gases is found in which of the following pairs of mammalian blood vessels?

the pulmonary vein and the jugular vein

Circulatory systems compensate for ____.

the slow rate at which diffusion occurs over large distances

The velocity of blood flow is the lowest in capillaries because____.

the total cross-sectional area of the capillaries is greater than the total cross-sectional area of the arteries or any part of the circulatory system

Within a normally functioning kidney, blood can be found in

the vasa recta.

As a person goes from rest to full-effort exercise, there is an increase in the

tidal volume

Unlike most bony fishes, sharks maintain body fluids that are isoosmotic to seawater, so they are considered by many to be osmoconformers. Nonetheless, these sharks osmoregulate at least partially by _____.

tolerating high urea concentrations that are balanced with internal salt concentrations to seawater osmolarity

Unlike most bony fishes, sharks maintain body fluids that are isoosmotic to seawater, so they are considered by many to be osmoconformers. Nonetheless, these sharks osmoregulate at least partially by

tolerating high urea concentrations that balance internal salt concentrations to seawater osmolarity.

A human red blood cell in an artery of the left arm is on its way to deliver oxygen to a cell in the thumb. To travel from the artery to the thumb and then back to the left ventricle, this red blood cell must pass through _____.

two capillary beds

Which of the following is the correct sequence of blood flow in birds and mammals?

vena cava - right atrium - right ventricle - pulmonary artery

What phylum has closed circulatory system?

vertebrates

Osmoconforming sharks take in water, as needed,

via osmosis, as their body cells are slightly hyperosmotic to seawater.

Osmonconforming sharks take in water, as needed,____.

via osmosis, as their body cells are slightly hypersomotic to seawater

Countercurrent exchange is evident in the flow of _____.

water across the gills of a fish and the blood within those gills

Gas exchange is more difficult for aquatic animals with gills than for terrestrial animals with lungs because _____.

water contains much less oxygen per unit volume than air

Atmospheric pressure at sea level is equal to a column of 760 mm Hg. Oxygen makes up 21 percent of the atmosphere by volume. The partial pressure of oxygen (PO2) in such conditions is _____.

160 mm Hg

What is an open circulatory system?

An open circulatory system is one that has one or more hearts that has blood vessels and then one large space within it called the hemocoel.

The products of filtration in the renal corpuscle enter the renal tubule through which of the following structures?

Bowman's capsule

Salmon eggs hatch in freshwater. The fish then migrate to the ocean (a hypertonic solution) and, after several years of feeding and growing, return to freshwater to breed. How can these organisms make the transition from freshwater to ocean water and back to freshwater?

Different gill cells are involved in osmoregulation in freshwater than in salt water.

A decrease of blood pH from 7.4 to 7.2 causes hemoglobin to ____.

Give up more of its oxygen molecules

One of the waste products that accumulates during cellular functions is carbon dioxide. It is removed via the respiratory system. What other waste products may accumulate during normal physiological functioning in a vertebrate?

I, II, and III ammonia, uric acid, and urea

What role does Na+/K+-ATPase play in salt excretion by the shark rectal gland?

Na+/K+-ATPase pumps sodium out and potassium into cells across the basolateral membrane.

Which of the following most accurately describes selective permeability?

Only certain molecules can cross a cell membrane.

Which of the following events would you predict as carbon dioxide is released from your muscles into the surrounding capillary bed?

Oxygen delivery to muscle is increased when more carbon dioxide is produced by the muscle.

Some animals have no gills when young, but then develop gills that grow larger as the animal grows larger. What is the reason for this increase in gill size?

Relative to their volume, the young have more surface area across which they can transport all the oxygen they need

Tissues of sharks are isotonic to seawater, but their concentrations of sodium ions, potassium ions, and chloride ions in cells and extracellular fluids are similar to those of freshwater fishes. What can you infer about the movement of sodium and chloride in these animals?

Sodium and chloride will diffuse into shark gills from seawater down their concentration gradient.

Carbonic anhydrase inhibitors cause less movement of carbonic acid toward carbon dioxide production and are used as a prophylactic treatment of altitude sickness. Altitude sickness occurs when a hiker ascends to altitudes where the density of oxygen is low. How does this decrease the symptoms of high altitude sickness?

The excess bicarbonate ions are excreted in the urine and the resulting increase in blood acidity leads to an increase in ventilation.

What adaptations are observed in the trachea and lungs to reduce water loss?

The location of the trachea and lungs (inside of the body) reduced water loss.

What adaptions are observed in the trachea and lungs to reduce water?

The locations of the trachea and lungs (inside of the body) reduces water loss.

When you are jogging, your muscles are using more oxygen and releasing more carbon dioxide into the blood than when you are at home on the couch. Which of the following would occur during your jog?

The medullary respiratory center would detect rising carbon dioxide levels.

Which of the following statements comparing respiration in fish and in mammals is correct?

The movement of the respiratory medium in mammals is bidirectional, but in fish it is unidirectional.

A rabbit taken from a meadow near sea level and moved to a meadow high on a mountainside would have some trouble breathing. Why?

The partial pressure of oxygen in the air at high elevations is lower than at sea level

What is the function of the osmotic gradient found in the kidney? The osmotic gradient allows for

The precise control of the retention of water and electrolytes

Why are the renal artery and vein critical to the process of osmoregulation in vertebrates?

The renal artery delivers blood with nitrogenous waste to the kidney and the renal vein brings blood with less nitrogenous wastes away from the kidneys

Blood is pumped at high pressures in arteries from the heart to ensure that all parts of the body receive adequate blood flow. Capillary beds, however, would hemorrhage under direct arterial pressures. How does the design of the circulatory network contribute to reducing blood pressure to avoid this scenario?

The total cross-sectional diameter of the arterial circulation increases with progression from artery to arteriole to capillary, leading to a reduced blood pressure.

Glucose is removed in the proximal convoluted tubules. Therefore, glucose is not expected to be found in a normal urine sample. However, glucose is found in the urine of diabetics. Why is this the case?

The transport of glucose from the pre-urine back to the blood cannot occur at a rate fast enough to remove all of the glucose from the urine.

When a cell is in equilibrium with its environment, which of the following occurs for substances that can diffuse through the cell?

There is random movement of substances into and out of the cell.

What role do chloride cells play in osmoregulation of marine fish with bony skeletones?

They are involved in excretion of excess salt

What role do chloride cells play in osmoregulation of marine fish with bony skeletons?

They are involved in excretion of excess salt.

One reason carbon dioxide is converted to bicarbonate and H+ in red blood cells is__________.

To maintain a higher partial pressure gradient between tissue and red blood cells favoring the diffusion of CO2 from tissue into the red the blood cells

The figure above shows a nephron. Filtration of large molecules takes place in a the structure labeled

a

If you are hiking through the desert for several days, one would pack which of the following to ensure proper hydration?

a drink with a combination of water and electrolytes

Natural selection should favor the highest proportion of juxtamedullary nephrons in which of the following species?

a mouse species living in a desert

You are a physician, and you are seeing a patient who complains of abnormal fatigue during exercise. You find that the immediate problem is a buildup of carbon dioxide in the tissues. What is the most likely cause?

abnormal carbonic anhydrase

Consider the following reaction. If the pH of the blood was decreased, then the ____.

amount of carbon dioxide would increase

Cyanide poisons mitochondria by blocking the final step in the electron transport chain. Human red blood cells placed in an isotonic solution containing cyanide are likely to _____.

be unaffected

In order for blood to always flow unidirectionally through a closed circulatory system, the ___.

blood vessels farthest from the heart must have valves

Which of the following conditions would most likely be due to high blood pressure in a mammal?

bursting of blood vessels in capillary beds

During most daily activities, the human respiration rate is most closely linked to the blood levels of ___.

carbon dioxide

Breathing is primarily regulated by _____.

carbon dioxide concentration and pH-level sensors

If other factors are equal, which of the following environments would have the highest level of dissolved oxygen?

cool freshwater at low elevation

During aerobic exercise, the partial pressure of oxygen in muscle cells will ___, thus the rate of diffusion of oxygen into the muscle tissue from the blood will____.

decrease; increase

Large proteins such as albumin remain in capillaries rather than diffusing out, resulting in the ___.

development of an osmotic pressure difference across capillary walls

The loop of Henle dips into the renal cortex. This is an important feature of osmoregulation in terrestrial vertebrates because ____.

differential permeabilities of ascending and descending limbs of the loop of the Henle are important in establishing an osmotic gradient.

The high osmolarity of the renal medulla is maintained by all of the following except

diffusion of salt from the descending limb of the loop of Henle.

Damage to the sinoatrial node in humans would ____.

disrupt the rate and timing of cardiac muscle contractions

Birds that live in marine environments, and thus lack access to fresh drinking water, _____.

drink seawater and secrete excess ions mainly through their nasal salt glands

To maintain homeostasis freshwater fish must _____

excrete large quantities of water

A human who has no access to fresh water but is forced to drink seawater instead will _____.

excrete more water molecules than taken in, because of the high load of ion ingestion

Low selectivity of solute movement is a characteristic of

filtration from the glomerular capillaries.

If, during protein starvation, the osmotic pressure on the venous side of capillary beds drops below the hydrostatic pressure, then _____.

fluids will tend to accumulate in tissues

Among the following choices, which organism likely has the highest systolic pressure?

giraffe

Excessive formation of uric acid crystals in humans leads to

gout, a painful inflammatory disease that primarily affects the joints.

Why is the pharmacological reactivation of fetal hemoglobin in a patient with sickle-cell anemia often a successful treatment? Fetal hemoglobin

has a higher affinity for oxygen than does adult hemoglobin

Under identical atmospheric conditions, freshwater _____.

has more oxygen than seawater

In humans, the transport epithelial cells in the ascending loop of Henle

have plasma membranes of low permeability to water.

Compared with the interstitial fluid that bathes active muscle cells, blood reaching these muscle cells in arteries has a _____.

higher PO2

The partial pressure of oxygen (PO2) in the atmosphere at sea level is

higher than PO2 in body tissue

Human urine is usually more acidic than most other body fluids because

hydrogen ions are actively moved into the filtrate.

Marine vertebrates are _____ to their environment.

hypotonic

If ATP production in a human kidney was suddenly halted, urine production would

increase, and the urine would be isoosmotic compared to plasma.

Which of the following pairs of organisms excrete nitrogenous wastes in the form of uric acid?

insects and birds

The transfer of fluid from the glomerulus to Bowman's capsule

is mainly a consequence of blood pressure in the capillaries of the glomerulus.

Compared to the seawater around them, most marine invertebrates are

isoosmotic

The body fluids of an osmoconformer would be ________ with its ________ environment.

isoosmotic; saltwater

A primary reason that the kidneys have one of the highest metabolic rates of all body organs is that

it operates an extensive set of active-transport ion pumps.

A necropsy (postmortem analysis) of a marine sea star that died after it was mistakenly placed in fresh water would likely show that it died because

it was so hyperosmotic to the fresh water that it could not osmoregulate.

An excretory system that is partly based on the filtration of fluid under high hydrostatic pressure is the

kidneys of vertebrates.

Which of the following represents the correct flow of air into the lung of a mammal?

larynx - trachea - bronchi - bronchioles - alveoli

Blood returning to the mammalian heart in a pulmonary vein drains first into the

left atrium

Urea is produced in the

liver from NH3 and CO2.

The necropsy (postmortem analysis) of a freshwater fish that died after being placed accidentally in saltwater would likely show that _____.

loss of water by osmosis from cells in vital organs resulted in cell death and organ failure

Processing of filtrate in the proximal and distal tubules

maintains homeostasis of pH in body fluids.

What 3 phylum have open circulatory system?

mollusks, arthropods and annelids

The filtrate in the proximal convoluted tubule of the human does not normally include

plasma proteins.

What would be the consequences if we were to reverse the direction of water flow over the gills of a fish, moving water inward past the operculum, past the gills, the out the mouth? This reversal of water flow would _____.

reduce efficiency of gas exchange

The fluid with the highest osmolarity is

seawater in a tidal pool

The osmoregulatory process called secretion refers to the

selective elimination of excess ions and toxins from body fluids.

Materials are returned to the blood from the filtrate by which of the following processes?

selective reabsorption

Which of the following develops the greatest pressure on the blood in the mammalian aorta?

systole of the left ventricle

The filtrate in the renal pelvis enters directly from

the collecting duct.

The force driving simple diffusion is _____, while the energy source for active transport is _____.

the concentration gradient; ATP

Carbon dioxide levels in the blood and cerebrospinal fluid affect pH. This enables the organism to sense a disturbance in gas levels as ____.

the medulla oblongata, which is in contact with cerebrospinal fluid, monitors pH and uses this measure to control breathing