Anat & Phys 235 Final
In which region of the mammalian nephron is the reabsorption of water and salt regulated to determine final urine osmolarity and volume?
**NaCl& H2O reabsorption in DT & CD regulated by hormones to homeostaticallymaintain ECF osmolarity, volume and pressure**
Describe the role of ATP in each of the steps of the crossbridge cycle.
-ATP binds to myosin, myosin released from actin myosin breaks ATPase down ATP -the energy released rotates the myosin head and binds weakly to actin stored as potential energy -head of myosin
What is a membrane potential (Vm)?
-a gradient that forces ions to passively move in one direction: positive ions are attracted by the 'negative' side of the membrane and negative ions by the 'positive' one. -A separation of charge across the plasma membrane. -exists in ALL cells. By convention, the outside is considered zero. At rest,Vm is negative. Vm=Vin-Vout -70mV
Why is it important that the distance between the air in the alveoli and the blood in the pulmonary capillaries is very short?
-air sac is covered in capillaries -fast/efficient diffusion
What are the two subdivisions of the efferent nervous system? What are the two branches of the autonomic nervous system (ANS) and what are their primary responsibilities in maintaining homeostasis?
-autonomic and somatic -parasympathetic -rest/digest and sympathetic-fight/flight
Both CO2 and CO bind to hemoglobin (Hb), but only CO disrupts Hb transport of O2. Why?
-carbon monoxide has a greater affinity for hemoglobin than oxygen -when CO is present it binds to hemoglobin over O2 -as a result O2 cannot bind to hemoglobin
What is osmosis?
-diffusion of H2O -Water diffuses through aquaporins down its concentration gradient
What is the primary stimulus for changes in ventilation? In other words, what controls the moment-to-moment breathing rate?
-increased concentration of carbon dioxide is the strongest stimulus to breathe more deeply and frequently -reflected by changes in pH
How is the partial pressure of oxygen, 160 mm HG, calculated?
-inspired air is 21% O2' -atmospheric pressure is 760mmHg(sea level) =21% x 760mmhg=160mmHg
What is sensory transduction? How are receptor potentials similar to and different from postsynaptic potentials?
-sensory stimulus converted to changes in membrane potential (receptor potential) -specialized structure at peripheral end of afferent neuron -a seperate cell communicating through a chemical synapse
What type of molecule are enzymes and what role do they play in chemical reactions?
-they are biomolecules(almost always proteins) -act as catalysts that increase rates of chemical reactions/speeds them up
What are the major functions of the stomach?
1) mechanical breakdown of ingested food into chyme 2) chemical digestion of protein and fat gastroilealreflex•food in stomach triggers peristalsis in the ileum and opening of the ileocecalvalve-gastrocolicreflex•food in the stomach triggers mass movement in the large intestine
How is the resting membrane potential generated and maintained in a cell?
1. The Na-K pump: a.3 Na+ out for every 2 K+ in leads to a net loss of positive charges (pump is electrogenic-net negative inside) b. Establishes and constantly maintains the Na+ and K+ concentration gradients 2.Na+and K+ diffuse across the membrane down their concentration gradients through open ion channels 3. The resting membrane is more permeable to K+, therefore ERest is closer to EK than to ENaThe resting membrane is more permeable to K+, therefore ERest is closer to EK than to ENa
In what two forms is O2 transported in the blood? Which form is most abundant?
1. 98% Diffuses into red blood cells (RBC) and bind to Hemoglobin (Hb) to form oxyhemoglobin (HbO2) -most abundant 2. 2% Dissolved in plasma
Describe the four integrated processes that collectively are called external respiration. For which processes is the respiratory system responsible? For which processes is the cardiovascular system responsible? Draw a picture to trace the path of an O2 and CO2 molecule through these events.
1. Pulmonary ventilation (exchange 1) -Exchange of air between atmosphere and lungs - bulk flow -resp system 2. Gas exchange 2 -Exchange between external air and capillaries across alveolar walls (lungs to blood) -exchange of oxygen and carbon dioxide between lung air spaces and blood by diffusion -resp system -oxygen(from alveoli), dissolves in plasma, diffuses into RBC and binds with hemoglobin -oxygen loaded into blood, carbon dioxide is unloaded -gases diffuse down pressure gradients -PO2=160 mmHg -PCO2=.23mmHg 3. Transportation -transportation of oxygen and carbon dioxide between lungs and body tissues -98% O2 diffuses into RBC and bind to hemoglobin -2% dissolved in plasma -7% CO2 dissolved in plasma -93% diffuses in RBC -23% bound to hemoglobin -70% bicarbonate 4.Gas exchange 3 -exchange of oxygen and carbon dioxide between blood and tissue by diffusion -capillaries and tissue -cardiovascular system -CO2 from tissue to blood -CO2 diffuses out of cells into capillaries -HCO3 enters plasma in exchange for chloride -at lungs, dissolved CO2 diffuses out of plasma -CO2 unbinds from hemoglobin and diffuses out of RBC -carbonic action reaction reverses, pulling HCO3 back into RBC and converting it back to CO2
In what three forms is CO2 transported in the blood? Which form is most abundant?
1. dissolved directly in blood -bound to plasma proteins or hemoglobin -converted into bicarbonate(most abundant)
What are the four tissue/cell types and their main functions?
1. muscle -stimulation and contracting to provide movement 2. epithelial -sheets of cells that cover exterior surfaces of body, line internal cavaties and form certain glands 3.connective -binds the cells and organs together and functions in protection, support and integration of the body 4. nervous -allowing the propogation of electrochemical signals in the form of nerve impulses that communicate between different regions of body
What are the four factors that determine membrane permeability of a substance and which has the strongest influence?
1. polarity 2. electric charge 3. molar mass
What three things control the level of free hormone circulating in the blood?
1. rate of hormone secretion 2. amount of hormone transported bound to carrier proteins 3. rate at which the hormone is metabolized
Outline the path of blood flow through the heart from its arrival into the right atrium until it is ejection from the left ventricle (include valves).
1. superior vena cava 2. right atrium 3. tricuspid valve 5. right ventrivle 5. pulmonary valve 6. pulmonary artery 7. lungs 8. pulmonary vein 9. left atrium 10. mitral valve 11. left ventricle 12. aortic valve 13. aorta 14. rest of the body
What are the three things that contribute to the magnitude of the cell's response to a chemical messenger?
1.Concentration of Messenger (amount present) 2. Number of receptors available •Up-regulation (increased sensitivity) •Down-regulation (decreased sensitivity) 3. Affinity of the receptor for the messenger
List the major functions of the kidney and briefly describe the importance of each to homeostasis.
1.Regulation of ECF volume and blood pressure2.Regulation of ECF osmolarity3.Maintenance of ECF ion balance4.Regulation of ECF pH5.Excretion of wastes (urea, uric acid)6.Production of hormones (erythropoietin, renin)
Explain the three defining characteristics that limit the rate of carrier-mediated transport. 1. Specificity 2.Saturation 3. Competition
1.Specificity •Each protein carries one or a couple of similar solutes 2.Saturation •Rate is limited by number of carrier proteins in the membrane •Transport Maximum, Tm 3.Competition •Limited number of solute binding sites on carrier proteins
Describe the 5 physical events of the crossbridge cycle.
1.binding of myosin to actin 2. powerstroke 3.rigor (myosin in low energy form) 4. unbinding of myosin and actin 5. cocking of the myosin head
. What are the three major factors that determine the rate of diffusion of a substance across a membrane?
1.lipid solubility 2.molecular size 3.concentration gradient 4.membrane surface area 5. compositon of lipid layer
What are the avenues of H2O input and output in humans?
2.2 L/day FOOD AND DRINK .3L/day metabolism=2.5 input skin, lungs, URINE ,feces= 2.5L/day output
In a human, what is the normal blood volume, plasma volume and plasma osmolarity? How much plasma is filtered per day by the kidneys? How much water is reabsorbed by the kidneys per day? How much urine is excreted per day?
5L blood (2L blood cells & 3L plasma): Kidneys filter 180 L of plasma per day
In which region of the mammalian nephron is the majority of the water and salt reabsorbed?
80% obligatorily reabsorbed-Proximal Tubule & descending loop
Identify and define the components of a neuroeffector junction. How does the neuroeffector junction differ from other neuron to neuron synapses? What ultimately triggers the release of Ca 2+ from each varicosity?
A neuroeffector junction is a site where a motor neuron releases a neurotransmitter to affect a target—non-neuronal—cell. This junction functions like a synapse. However, unlike most neurons, somatic efferent motor neurons innervate skeletal muscle, and are always excitatory.
In which part of the nephron is the permeability to H2O regulated? What hormone is primarily responsible for this regulation? What is the chemical class of the hormone? Which variable, ECF volume or ECF osmolarity, is this hormone homoestatically maintaining?
ADH(vasopressin) Regulates Collecting Duct H2O Permeability -peptide -ECF osmolarity
What are the normal partial pressures of O2 and CO2 in the following locations? Location PO2 PCO2 Atmospheric Air (at sea level) Alveoli Systemic arteries Systemic Veins cells
Alveolar PO2(100 mm Hg) > Capillaries PO2(40 mm Hg) Arterial PO2(100 mm Hg) > Tissue PO2(40 mm Hg) Tissue PCO2(46 mm Hg) > Capillaries PCO2(40 mm Hg) Venous PCO2 (46 mm Hg) > Alveolar PCO2(40 mm Hg)
Why are transporting epithelial cells described as polarized? (Note: The word polarized in this context does not refer to positive/negative.)
An epithelial cell is said to be polarized because one side differs in structure and function from the other. In particular, its plasma membrane is organized into at least two discrete regions, each with different sets of transport proteins.
What are the values of atmospheric pressure, intra-alveolar pressure, intrapleural pressure and transpulmonary pressure? Why are the differences between these values important?
Atmospheric pressure-760 mmhg intra-alveolar pressure -quantity of air molecules in the alveoli -volume of the alveoli intrapleaural pressure
Why can't steroid messengers be stored in the cell?
Because they are membrane permenant instead they diffuse out of the cell into the interstitial fluid as soon as they are synthesized
Explain whether and how materials exchange between the various body fluid compartments.
Blood capillary walls are very permeable ("free" exchange) Cell membrane is selectively permeable (regulated exchange) nutrients and waste pass between blood cells via the interstitial fluid
Describe the smooth muscle cells in the arterioles. What factors can influence arteriolar diameter?
Blood vessel diameter, blood viscosity, and total vessel length. If arteries lose their elasticity and become more rigid, blood pressure increases.
What signals trigger the contraction of cardiac muscle cells? What type of cells make up the conduction system and what does each type of cell do?
Contraction in each cardiac muscle fiber is triggered by Ca++ ions in a similar manner as skeletal muscle, but here the Ca++ ions come from SR and through voltage-gated calcium channels in the sarcolemma. Pacemaker cells stimulate the spontaneous contraction of cardiac muscle as a functional unit, called a syncytium.
What is atherosclerosis and which type of cholesterol can build up as plaque and where does this occur?
Coronary heart disease is leading cause of death in Americans•Elevated blood cholesterol Low-density lipoprotein-cholesterol (LDL-C) complexes
What is the difference between cortical and juxtameduallary nephrons? What important function do juxtameduallary nephrons serve?
Cortical nephrons (the majority of nephrons) start high in the cortex and have a short loop of Henle which does not penetrate deeply into the medulla. juxtamedullary nephron is a nephron whose renal corpuscle is near the medulla, and whose proximal convoluted tubule and its associated loop of Henle occur deeper in the medulla contribution to the osmotic gradient of the medulla, and it's this gradient that enables the kidneys to conserve water and secrete hypertonic urine.
In what two ways is the cardiovascular system critical to maintaining homeostasis (i.e. what does it deliver and what does it carry away)? What are the three components of the heart?
Delivers oxygen and nutrients to generate ATP -Delivers waste products to organ systems that eliminate them from the body 1. Heart 2. Blood vessels 3. Blood
Explain the differences between direct and indirect communication across cells. Give one example in the body of cells that use each type of communication.
Direct-through gap junctions indirect-chemical messangers
What is the normal osmolarity of the intracellular (ICF) and extracellular (ECF) fluid in humans?
ECF-280-295 ICF
In which part of the nephron is the permeability to Na+ regulated? What hormone is primarily responsible for this regulation? What is the chemical class of the hormone? Which variable, ECF volume or ECF osmolarity, is this hormone homoestatically maintaining?
Endocrine Reflexes: 1.Renin-Angiotensin-Aldosterone System (RAAS) 2.Atrial Natriuretic Peptide (ANP = anti-RAAS) -aldosterone -steroid
What are the two types of vesicular transport and in which direction across the plasma membrane do they transport substances?
Endocytosis-transport of substances into the cell Exocytosis-transport of substances out of the cell
Describe the extrinsic mechanism of regulation of GFR: baroreceptor reflex. Why is extrinsic regulation of GFR important?
Extrinsic Regulation (reduce filtration to conserve fluid) -nervous ---baroreceptor reflex:decrease MAP--sympathetic vasoconstriction -endocrine -----RAAS pathway:decrease MAP--angiotensin2--vasoconstriction
What two driving forces influence the direction an ion will move across the membrane and how do these two forces compare when the membrane potential is at the equilibrium potential for a given ion?
Forces (gradients) that influence which direction a substance will move across the plasma membrane. Electrochemical Gradient = concentration gradient + electrical gradient 1.Concentration (chemical) gradient -net flow from high to low concentrations -gradient does NOT change or dissipate; actively maintained in health 2.Electrical gradient •movement of charged substances is influenced by electrical gradients •depends on the membrane potential These two gradients can be in the same or opposite directions
Describe the composition of the filtrate (primary urine) in Bowman's capsule.
Glomerular filtrate—Fluid filtered from plasma into the urinary space (Bowman's space) after passage through the glomerular filtration barrier. It contains water, salts, ions, glucose, and albumin.
Briefly describe the difference between a glycolytic muscle fiber and an oxidative muscle fiber.
Glycolytic fibers primarily create ATP through anaerobic glycolysis, which produces less ATP per cycle. As a result, glycolytic fibers fatigue at a quicker rate. Slow oxidative fibers have structural elements that maximize their ability to generate ATP through aerobic metabolism.
How does an arterial baroreceptor respond to an increase and decrease in blood pressure? Provide specifics.
Increases in Blood Pressure •Parasympathetic output •Slows HR •Sympathetic inhibition •Dilation of arterioles •Lowers MAP Decreases in Blood Pressure •Sympathetic output •Increases HR (shortens AV delay) •Enhances force of myocardial contraction •Constriction of arterioles •Increases MAP
Explain how changes in volume and pressure in the lung create airflow in and out of the lung (inspiration and expiration). Which of these processes is passive at rest?
Inspiration -Skeletal muscles contract -Diaphragm flattens -Alveoli expand, pressure decrease Expiration -Passive process -Lungs recoil, pressure increase
define the function of each organ system Circulatory Gastrointestinal Endocrine Renal (Excretory) Immune & Lymph Integumentary Muscular Nervous Reproductive Respiratory Skeletal
Integumentary-Maintain boundaries: inside outside and between inside compartments Nervous/endocrine-Coordinate functions throughout the body Nervous/ endocrine-Sense and respond to changes in environment Muscular/skeletal-Movement Respiratory/CV- Transport substances throughout the body Respiratory, CV-Exchange gases w/environment: obtain O2 & eliminate CO2 Muscular/Gastrointestinal/CV-Obtain nutrients and water Gastrointestinal, CV-Digest nutrients Renal, CV-Excrete wastes Gastrointestinal/Renal/ CV-Maintain water and salt balance Respiratory/Renal/CV-Maintain pH Endocrine/Immune/ CV-Grow and repair damage Muscular/Nervous-Maintain temperature Immune/CV/Lymphatic-Fight off foreign invaders
What is the difference in the way that ion channels function and carrier proteins function?
Ion channels are protein molecules that span across the cell membrane allowing the passage of ions from one side of the membrane to the other. They have an aqueous pore, which becomes accessible to ions after a conformational change in the protein structure that causes the ion channel to open. Ion channels are selective meaning that they only allow certain ions to pass through them, and they play critical roles in controlling neuronal excitability. Ion channels are divided into those that are opened by changes in membrane potential, voltage-gated ion channels, and ion channels that are opened by the binding of a ligand, such as a hormone or a neurotransmitter, ligand-gated ion channels. The carrier proteins facilitate diffusion of molecules across the cell membrane. The protein is imbedded in the cell membrane and covers the entire membrane. This is important because the carrier must transport the molecule in and out of the cell.
Describe the roles that local and long-distance signals have regarding local cell and tissue function and the maintenance of homeostasis. When might these two types of signals be in conflict?
Local feedback signals minimize changes in local conditions (e.g., tissues control their own blood flow) Long distance signals coordinate function across long distances in order to maintain homeostasis (e.g., balancing blood flow to all parts of the body) Signals may conflict when the organism is under stress (e.g., hemorrhage, shunt blood flow to most important organs)
What are the four basic processes used by the GI system?
Motility& Secretion are regulated to maximize Digestion& Absorption
What are the two sensory receptors located in skeletal muscle? How do they work to prevent injury?
Muscle spindles are skeletal muscle sensory receptors within the body of a muscle that primarily detect changes in the length of this muscle contributing to fine motor control and providing axial and limb position information to the central nervous system.
What are some of the muscle adaptations that occur with exercise training?
Muscles adapt to increasing levels of stress by increasing their function. Disuse leads to decreasing strength and muscle mass. Atrophy results in a decrease in both contractile and sarcoplasmic protein. The muscle fiber types do not atrophy at the same rate.
What are the two major homeostatic control systems in the body?
Nervous Endocrine
how will the concentration gradient of K+ change following an action potential?
Normally the concentration of K+ is higher inside the neuron than outside. After the repolarizing phase of the action potential, K+ leakage channels and the Na+/K+ pump ensure that the ions return to their original locations. Following a stroke or other ischemic event, extracellular K+ levels are elevated. The astrocytes in the area are equipped to clear excess K+ to aid the pump. But when the level is far out of balance, the effects can be irreversible.
Define the components of the equation: Flow = P atm -P alv /R. Which value in the numerator is the most important? Is this similar to the equation used in the cardiovascular system to determine blood flow? What two factors determine Intra-alveolar pressure? What is the primary source of resistance in this equation?
Patm-atmospheric pressure, 760 mmhg Palv-intra-aveolar pressure -quantity of air molecules in the alveoli -volume of the alveoli
What are the primary homeostatic functions performed by the gastrointestinal system?
Primary functions:-ingestion, digestion and absorption of nutrients (food)-elimination of indigestible remains-defense against ingested invadersCoordination with CV system for transport of nutrients
What are transport epithelia and how are they involved in kidney function?
Reabsorption & Secretion Occur via Transepithelial Transport
What is homeostasis?
Regulation of an organism's internal environment (ECF) within limits compatible with cell survival
What are some of the many roles that Ca 2+ plays in skeletal muscle contraction and relaxation?
Relaxation of skeletal muscle occurs when the intracellular Ca2+ concentration returns to nearby resting levels allowing troponin to return in the closed position in which binding of myosin heads to actin is blocked The outflow of calcium allows the myosin heads access to the actin cross-bridge binding sites, permitting muscle contraction.
What are the major processes controlled by the endocrine system? What are some endocrine glands.
Reproduction - Growth and development - Mobilizing body defenses against stressors - Maintaining electrolyte, water and nutrient balance - Regulating cellular metabolism and energy balance endocrine glands -pineal, pituitary
What are short and long reflexes in the GI tract and which divisions of the nervous system regulate each type?
Short reflexes to the digestive system provide shortcuts for the enteric nervous system (ENS) to act quickly and effectively, and form a sort of digestive brain -enteric nervous system long reflexes -coordinates GI activity with the rest of the ---body•coordinates activity between distant parts of the --GI tract•modify ENS & GI hormone activity -CNS
Where do slow waves originate? At what frequency do they occur in different regions of the GI tract?
Slow waves originate in specialized pacemaker regions such as the border between the circular and longitudinal muscle layers in the stomach and small intestine
Why do some substances require the input of energy from an outside source (e.g. ATP) to be transported across the plasma membrane?
Solutes move against concentration gradient
What is the underlying difference between how fast a muscle can contract and how long it can stay contracted? a. What are the two factors that determine the amount of force a muscle can produce?
Speed of contraction (time to peak tension) -Isoform of myosin ATPase expressed in thick filament -Glycolytic vs Oxidative fibers Twitch duration -Speed of Ca2+ removal
Define stroke volume and cardiac output. How might these values change with increases in heart rate?
Stroke volume- the volume of blood pumped from the left ventricle per beat. cardiac output-the volume of blood being pumped by the heart, in particular by the left or right ventricle, per unit time If heart rate increases, then stroke volume will have to decrease to maintain a normal cardiac output If heart rate increases, cardiac output increases
How are the Na+ and K+ concentration gradients in a resting cell established and maintained?
The Na+/K+ pump moves Na+ out of the cell and K+ into the cell against their concentration gradients. The leak channels allow Na+ and K+ to move across the cell membrane down their gradients (from a high concentration toward a lower concentration).
What feature of the cardiovascular system allows blood to flow in one direction (i.e. from atria to ventricle, opening/closing of valves)?
The Pumping Action/valves. Your heart uses its four valves to ensure your blood flows only in one direction. Healthy valves open and close in coordination with the pumping action of your heart's atria and ventricles. Each valve has a set of flaps called leaflets or cusps.
What is the lowest voltage (estimate) of the unstable membrane potential for a pacemaker cell and how is this involved in the depolarization process? What controls the speed of pacemaker depolarization in the heart?
The SA node controls the rate of contraction for the entire heart muscle because its cells have the quickest rate of spontaneous depolarization, thus they initiate action potentials the quickest
How do action potentials propagate down an axon that is not myelinated? How do they propagate down an axon that is myelinated?
The action potential travels down the axon as voltage-gated ion channels are opened by the spreading depolarization. In unmyelinated axons, this happens in a continuous fashion because there are voltage-gated channels throughout the membrane. Propagation of an action potential in a myelinated nerve involves the opening and closing of ion channels exclusively at the Nodes of Ranvier. This saltatory conduction accelerates the rate at which an action potential travels down an axon.
Why is the adrenal medulla considered a modified presynaptic ganglia? How does this differ from other sympathetic activity and what neurohormone does it release? What types of cells secrete the neurohormone?
The adrenal medulla itself is modified neural tissue and its activity is regulated by a direct neural input. So the medulla functions like a modified sympathetic ganglion. releases epinephrine secreted into blood
What is an equilibrium potential (E ion) and what determines it for each ion?
The membrane potential at which an ion is at equilibrium across the plasma membrane (influx = outflux; zero net flux) Specific to one ion (Eion) Depends on: 1. concentration gradient across the membrane 2. charge of the ion
Explain the anatomical relationship between the pleural membrane on the lung, the pleural membrane on the inside of the chest wall, and the pleural space between them. Why is this relationship important for normal lung function?
The parietal pleura lines the thoracic wall and superior surface of the diaphragm. It continues around the heart forming the lateral walls of the mediastinum. The pleura extends over the surface of the lungs as the visceral pleura. The surface tension of the fluid in the pleural cavity secures the pleura together.
To which ion is the resting cell membrane most permeable, Na + or K + ?
The resting membrane is more permeable to K+, therefore ERest is closer to EK than to ENa
Describe where to find oxygenated blood and where to find deoxygenated blood. Do these two divisions ever mix blood?
The right side pumps deoxygenated blood (low in oxygen and high in carbon dioxide) to the lungs. The left side pumps oxygenated blood (high in oxygen and low in carbon dioxide) to the organs of the body.
Where in the CNS are the cell bodies of somatic neurons located and where do they synapse?
The somas of sensory neurons are located in dorsal root ganglia. The somas of motor neurons are found in the ventral portion of the gray matter of the spinal cord.
How do the different divisions of the Autonomic Nervous System impact heart rate(include chemical signals/receptor type)?
The sympathetic nervous system (SNS) releases the hormones (catecholamines - epinephrine and norepinephrine) to accelerate the heart rate reduced heart rate results from an increase in activity of the parasympathetic nervous system,
Why are skeletal muscles referred to as 'striated muscle'? a. What are the major components of a myofibril? b. Which components are the contractile proteins and which are the regulatory proteins?
They are striated under a microscope. troponin actin tropomyosin myosin contractile proteins: -myosin -actin Regulatory proteins -troponin -tropomyosin
Write the chemical reaction that shows the relationship between CO2 and HCO3- and H+ in the blood. In which direction is this reaction driven in the lungs? In the tissues? How does this impact the pH of the blood?
Tissues CO2+ H2O---H2CO3---H+ + HCO3- Lungs lungs -directed to free CO2 so it can release CO2 -arrow to the left tissue -attracted toward H+ so it can transport to the lungs -arrow to the right the respiratory system works collaboratively with the urinary system to maintain pH homeostasis. a change in the ratio will affect pH of the fluid, if both components change pH may be normal but the other components will not
Are veins the pressure or volume reservoir? What does this mean? Describe the factors that influence venous pressure and venous return.
Volume The blood in veins is referred to as a "Reservoir" because it can be mobilized to boost cardiac output and in turn systemic arterial pressure when physiological demands require so. Determinants of Venous Return. Everywhere in the body, pressure gradients and resistances determine blood flow rate. When considering venous return, the pressure gradient is mean systemic pressure minus the right atrial pressure, and resistance is the total peripheral vascular resistance.
What is plasma clearance? What is the formula to calculate the clearance of a substance? What is relative clearance?
Volume of plasma cleared of a particular substance per minute (ml plasma/min) CS= USVS/ PS Note: RPCS= CSS = substanceCS= clearance of substance S (ml plasma/min)US= urine concentration of substance S (mg/ml)VS= rate of urine formation (ml/min)PS= plasma concentration of substance S (mg/ml)
Which of the three major types of nutrients are absorbed through the wall of the small intestine via active transport and which are absorbed by passive diffusion? Which are absorbed into the blood capillary and which into the lacteal?
Water and lipids are absorbed by passive diffusion Sodium bicarbonate is absorbed by active transport
What are the primary homeostatic functions performed by the respiratory system?
What are the primary homeostatic functions performed by the respiratory system? Gas exchange with the external environment Diffusion, exchange surface Coordination with CV system for transport of gases Other functions Regulation of pH, protection and vocalization, route for water and heat loss, venous return
When is vesicular transport used?
When macromolecules are too large to cross the plasma membrane even with the assistance of carrier proteins.
What is the primary difference between a type I and type II alveolar cell? Which type of cell has a more important job?
While type I cells are generally passive in nature, type II cells are highly metabolic, allowing these cells to perform three important activities that keep the alveolus functioning normally: surfactant production, surfactant homeostasis, and repair of the alveolus following injury
Explain what lung compliance is and why having a large compliance is advantageous. How does pulmonary surfactant affect lung compliance?
a measure of the lung's ability to stretch and expand
How is an 'axis' defined in the endocrine system? Give an example of an axis in the endocrine system.
a number of glands that signal each other in sequence ex. the hypothalamic-pituitary adrenal axis
What are the absolute and relative refractory periods? Explain how the Na + channel states are responsible for generating each of these.
absolute-no stimulus can trigger another potential relative- only a larger than normal stimulus can initiate a new action potential the membrane is refractory when na channels are inactivated and not able to generate another action potential
What are the major functions of the small intestine?
absorption of nutrients and minerals from food. acid in the duodenum slows gastric emptying
What is the enterogastric reflex and what does it regulate?
acid in the duodenum slows gastric emptying in small intestine
What role does myelin play in neural cell function?
acts as insulator, speeds up electrical signals
Why is maintaining ECF K+ concentrations at homeostatic levels so important? What hormone is responsible for regulating K+ secretion in the nephron? How is this related to Na+ reabsorption?
aldosterone regulates Aldosterone stimulates Na+ and water reabsorption from the gut, salivary and sweat glands in exchange for K+
Which rate of ventilation, total pulmonary ventilation or alveolar ventilation, is a better measure of how much fresh air reaches the gas exchange surface in the lung? Explain.
alveolar ventilation is a better measure -specific gas exchange -more efficient to increase alveolar ventilation by increasing tidal volume than by increasing respiration rte
Describe the relationship between filtration, reabsorption, secretion and excretion in the kidney (equation).
amount filtered-amount reabsorbed +amount secreted=amount excreted
Define signal amplification and describe why this process is important when discussing chemical messengers.
amplifying a signal by sending more of it..higher concentration..if you are actually scared your brain will recognize and send more epinephrine if you have a higher concentration then a stronger reaction if you have a lower reaction then a lesser reaction a gradient is desired
What are zymogens and why are they important for normal GI function?
an inactive substance which is converted into an enzyme when activated by another enzyme. help with digestion in small intestine
What is the role of venous return and afterload in regulating stroke volume? What are 3 factors that influence stroke volume?
an increase in venous return to the heart increases the filled volume (EDV) of the ventricle, which stretches the muscle fibers thereby increasing their preload. This leads to an increase in the force of ventricular contraction and enables the heart to eject the additional blood that was returned to it. 1. preload-The filling pressure of the heart at the end of diastole. 2.contractility-The inherent vigor of contraction of the heart muscles during systole. 3.afterload-The pressure against which the heart must work to eject blood during systole.
What term describes the relationship between parathyroid and calcitonin? Additive Synergistic Antagonistic Permissive
antagonistic-opposes the action of another
5. For each of the major hormones listed below, answer the following questions: a. What is/are the primary functions or actions of the hormone and what is its role in maintaining homeostasis (if relevant)? b. Which glands secrete the hormone and what are the hormone's target tissue(s)? c. What is the chemical nature of the hormone? d. By what feedback mechanism is secretion of the hormone regulated?
antidiuretic hormone/vasopressin -tells kidneys how much water to conserve -acts to maintain blood pressure, blood volume and tissue water content by controlling amount of water and concentration of urine excreted by kidney -pituitary gland -kidney tubules and smooth muscles in arterioles -synthesized as peptide prohormone in neurons in the hypothalamus, converted to AVP -produced by hypothalamus and stored in posterior pituitary gland. ADH normally released by pituitary in response to sensors that detect increase in blood osmolarity or decrease in blood volume thyrotropin (TSH) -master regulator of thyroid gland growth and function -controls bodys metabolic rate, heart generation, neuromuscular function and heart rate -pituitary -target thyroid gland -regulated by hypothalamus, produces thyrotopin releasing hormone Cortisol -control blood sugar levels, regulate metabolism, reduce inflammation, assist with memory formulation -secreted by adrenal gland -target tissues, liver, fat, muscle -in the glucocorticoid class -hypothalamus and pituitary bland can sense if your blood contains the right level of cortisol..if too low your brain adjusts the amount of hormones it makes...adrenal glands pick up on these signals then they fine-tune the amount of cortisol they release growth hormone -stimulates growth of all tissues in body -secreted by pituitary gland -targets liver -amino acid-single chain polypeptide that is synthesized secreted by somatotropic cells in anterior pituitary gland -regulated by hypothalamus and the mediators of GH actions insulin -allows body to use glucose from carbohydrates for energy or to store glucose for future use -pancreas secretes it -targets liver and skeletal muscle -polypeptide
Compare and contrast the diameter of an artery, arteriole, venule and vein and explain how these differences affect blood flow and oxygen exchange.
artery-thick walls that can withstand the high pressure of blood ejected from the heart arteriole-small diameter, increases resistance and slows blood flow venule-8-100 micrometers, very small vein-bigger, low pressure
If the SA node is not setting the heart rate pace, what other clusters of cells will ensure a steady heart rate?
av node
Why are humans unable to digest the cellulose found in plants? What happens to the cellulose that humans eat?
because the appropriate enzymes to breakdown the beta acetal linkages are lacking. (More on enzyme digestion in a later chapter.) Undigestible cellulose is the fiber which aids in the smooth working of the intestinal tract.
Why are the conduction fibers of the heart able to respond quickly to signals from the pacemaker cells?
because they transmit action potentials through the heart
Describe the pressure changes as blood leaves the heart, travels to the tissues and back to the heart.
blood is pushed under high pressure and velocity away from the heart
What are the three major types of nutrients, into what forms must they be digested in order to be absorbed, and which types of enzymes are responsible for their chemical digestion?
carbohydrate, protein, and fat.
The four types of biomolecules in the human body are listed below. What are the chemical components of each and what roles do they play in the human body? Carbohydrates Lipids Proteins Nucleotides and Nucleic acids
carbohydrates -carbon, hydrogen, oxygen -polar molecules -dissolve easily in water -provide energy lipids -carbon and hydorgen linked together by nonpolar covalent bonds -nonpolar molecules -dont dissolve in water -store energy proteins -carbon, amino group, carboxyl group, hydrogen and residual R group -provide structure and function nucleotides/nucleic acids -5 carbon carbohydrate, nitrogenous base, one or more phosphate groups -units that form DNA and RNA -pyrimidines contain a single carbon ring -purines contain a double carbon ring -nucleic acids function in storage and expression of genetic information -DNA found in cells nucleus -RNA found in nucleus and cytoplasm
What are the main functions of these regions of the brain? cerebral cortex - thalamus - hypothalamus - limbic system - brain stem - cerebellum -
cerebral cortex-neural integration thalamus-sensory relay center hypothalamus-regulating endocrine control limbic system-manages fear and emotions brainstem-heart rate/breathing cerebellum-coordinate motor functions
What are the three categories of receptors that a hydrophilic messenger can bind with and what is the general mechanism of influence?
channel linked receptors -the ligand is a messanger that binds to a receptor -allow only one type of ion to pass through them Enzyme linked receptors -function as both enzymes and receptors -enzymes become activated when a messanger binds to the receptor allowing them to catalyze intracellular reactions G-Protein linked receptors -activate special membrane g proteins -g-proteins act as molecular switches inside cells and are involved in transmitting signals from a variety of stimuli outside a cell to its interior
What are some of the reasons an end-plate potential is much larger than an ordinary postsynaptic potential?
chemically induced change in electric potential of the motor end plate, the portion of the muscle-cell membrane that lies opposite the terminal of a nerve fibre at the neuromuscular junction. The end-plate membrane is electrically polarized, the inside being negative with respect to the outside because of an uneven distribution of ions. When a nerve impulse releases the neurotransmitter acetylcholine from the nerve terminal, it binds to channel-shaped receptor molecules on the end plate, opening the channels and allowing positively charged sodium ions to flow into the muscle cell. This redistribution of ions slightly depolarizes the membrane. An enzyme then rapidly degrades the acetylcholine, closing the channels and allowing the membrane to return to its previous polarized state. Postsynaptic potentials are changes in the membrane potential of the postsynaptic terminal of a chemical synapse. Postsynaptic potentials are graded potentials, and should not be confused with action potentials although their function is to initiate or inhibit action potentials. They are caused by the presynaptic neuron releasing neurotransmitters from the terminal bouton at the end of an axon into the synaptic cleft. The neurotransmitters bind to receptors on the postsynaptic terminal, which may be a neuron or a muscle cell in the case of a neuromuscular junction. These are collectively referred to as postsynaptic receptors, since they are on the membrane of the postsynaptic cell.
What are the three states that the voltage-gated Na + channels that produce action potentials go through and what triggers them to move from one state to the next?
close, open, inactive at resting membrane potential, the activation gate closes the channel depolarizing stimulus arrives at the channel, activation gate opens, threshold potential reached and many na channels open rapidly with activation gate open, na enters the cell, positive feedback loop brings more na channels
What are the two regions of the adrenal gland, what hormones are secreted from each region and what is the primary function of each (neuro)hormone?
cortex -mineralocorticoids:regulates sodium reabsorption and potassium secretion to the kidneys -glucocorticoids:regulates bodys response to stress -sex hormones:regulate reproductive function medulla -epinephrine:increases heart rate and mobilization of energy stores during times of stress -norepinephrine -dopamine
Compare local control of vasoconstriction by PO2 levels in the interstitial fluid in the pulmonary and systemic capillaries. How does a decrease in PO2 in each location affect vasoconstriction? Explain why this is important to the function at each location.
decrease of PO2 in lungs -causes vasoconstriction b/c increasing amount of blood to highly ventilated areas decrease of PO2 in systemic tissues -causes vasodilation b/c you want blood to get to those tissues
By what three mechanisms are neurotransmitters removed from the synaptic cleft?
diffusion, degradation, reuptake
How are the following materials exchanged across the capillary wall? Small solutes_______, small lipid-soluble solutes________, small water-soluble solutes________, carbon dioxide________, large proteins_______.
diffusion, filtration, and osmosis.
Would continued exposure to higher than normal hormone amounts result in up-regulation or down-regulation of receptors for that hormone on the target cell?
down regulation- because the cell wouldnt want an overload of the hormone so they would have to have less opportunities for the hormone to enter the cell
Which type of synapse, electrical or chemical, conducts electrical signals from one cell to the next most quickly? Why?
electrical synapse conducts signals quickly because its bidirectional and gap junctions
What are the main functions of these types of glial cells? ependymal cells - astrocytes - microglial cells - oligodendrocytes & Schwann cells -
ependymal-lines ventricles astrocytes-release neurotransmitters, form BBB, provide infrastructure as support microglial cells-involved in immune response oligodendrocytes, schwann cells-from myelin
What type of signal triggers the generation of an action potential in a neuron? In other words, what brings the axon hillock to threshold?
excitatory postsynaptic potentials from a presynaptic neuron.
Describe the differences between these types of carrier-mediated transport across the plasma membrane: 1. facilitated diffusion 2. active transport i. primary (1) active transport ii. secondary (2) active transport
facilitated diffusion •Solutes move down concentration gradient •No ATP (energy) required Primary active transport •Solutes move against concentration gradient •ATP (energy) is used by the carrier protein secondary active transport •Solutes (glucose and H+) move against concentration gradient •Use energy from another substance's (Na+) concentration gradient
Post-synaptic potentials (PSP) are a type of graded potential and can either be fast or slow and can either be excitatory (EPSP, Excitatory Post Synaptic Potential) or inhibitory (IPSP, Inhibitory Post Synaptic Potential). What determines whether a PSP is fast or slow and whether it is excitatory or inhibitory?
fast-ionotropic, mediated by ion channels slow-metabotropic, mediated by G protein coupled receptor
What are the components of the filtration barrier and what is the filtration fraction?
filtration fraction-20% fenestrated endothelial cell, the glomerular basement membrane (GBM), and the podocyte with their "slit diaphragms". In all pathologic glomerular proteinuria, there is increased filtration of macromolecules (typified by albumin) across this barrier
What is the gastrocolic reflex and what does it regulate?
food in stomach triggers peristalsis in the ileum and opening of the ileocecal valve
What is the gastroileal reflex and what does it regulate?
food in stomach triggers peristalsis in the ileum and opening of the ileocecal valve
Explain what is meant by the equilibrium between free steroid chemical land bond steroid chemical. Which one can bind to the target receptor and how does this impact the other form?
free steroid chemical- steroid that moves freely (bloodstream) bond steroid chemical: steroid that binds to carrier protein
What is the difference between frequency coding and population coding? How is greater intensity of a stimulus conveyed in each type of coding?
frequency coding- frequency of action potentials population coding- number of receptors activated
What is a nephron and what does it do?
functional unit filtration reabsorption secretion excretion
What is the primary function of the autonomic nervous system?
homestasis- regulate function of effector organs
Describe the physical connection between the hypothalamus and the anterior pituitary and the connection between the hypothalamus and the posterior pituitary. What hormones are released from the anterior pituitary?
hypothalamus and anterior pituitary -hypothalamus connected to anterior lobe of pituitary gland by special portal bloom system -secretes tropic hormones which regulate secretion of other hormones hypothalamus and posterior pituitary -hypothalamus connected to posterior lobe of pituitary gland by neurons -nerve axons
Why is selective permeability of the cell membrane important for cell survival?
important in maintaining homeostasis, fluid and electrolyte balance and cellular health
List similarities and differences between contractile cardiac and skeletal muscle in their mechanisms of excitation-contraction coupling.
in contractile cardiac -gap junctions -ap travels along plasma membrane instead of sarcolemma -ca2+ incduces release from SR
How do the natruiretic peptides regulate renal function and what triggers their secretion?
increase in plasma volume and atrial wall stretch triggers there secretion they increase Na+ excretion and decrease aldosterone
Why is the resting membrane potential considered a steady state rather than an equilibrium state?
ions move across cell membrane such that constant resting membrane potential is achieved:ionic steady state maintenance of this steady state is used to do electrical and chemical work
From where and when are leptin and gherlin secreted and what are their functions?
leptin -secreted from fat cells -signals to the hypothalamus -acts to alter food intake and control energy expenditure over the long term. gherlin -secreted from stomach, small intestine, pancreas -stimulates appetite, increases food intake and promotes fat storage
In which directions are O2 and CO2 diffusing in the lung and in the tissue?
lungs -O2 diffuses from alveoli to blood -CO2 diffuses from blood to alveoli tissue -O2 diffuses from blood to tissue -CO2 diffuses from tissue to blood
What types of stimuli are sensed in the gastrointestinal tract, what kind of sensory receptors are used to sense each of them, and what kinds of responses do they trigger?
mechanical, thermal, osmotic and chemical
What are the functions of these membrane bound organelles (little organs) in the cell? 1. Mitochondria 2. Ribosomes 3. Rough endoplasmic reticulum (RER 4. Smooth endoplasmic reticulum (SER) 5. Golgi Apparatus 6. Lysosomes 7. Peroxisomes 8. Cytoskeleton 9. Centrioles
mitochondria-powerhouse of cell ribosomes-make protein to repair damage RER-produce proteins SER-detoxify body from metabolic wastes and drugs golgi apparatus-sorting and packaging proteins for secretion, transporting lipids lysosomes-digestion and waste removal peroxisomes-break down fatty acids cytoskeletan-helps cells maintain shape centrioles-cell division
How are sensory modality, stimulus location, stimulus intensity and stimulus duration conveyed in the sensory system?
modality- what, labeled line coding= specific pathway from receptor to CNS location- where, which receptive fields, lateral inhibition, convergence, two point discrimination intensity- strength, frequency of action potentials, number of receptors activated Duration- length, duration of action potentials, receptor adaption, tonic, phasic
What functions does saliva perform?
moistening food, and helping to create a food bolus, so it can be swallowed easily.
What are the components of the neuromuscular junction? What type of receptors are on the motor end plate?
motor neurons presynaptic axon terminal filled with synaptic vesicles (ACH)
Describe the two mechanisms of autoregulation (or intrinsic regulation) of glomerular filtration rate (GFR): 1) myogenic mechanism and 2) tubuloglomerular feedback. Why is autoregulation of GFR important?
myogenic mechanism arterioles contract when stretched tubuloglomerular feedback Juxtaglomerular apparatus: macula densa& granular cells increase flow past macula densa-- paracrine aaconstriction --decrease GFR It also allows the kidney to maintain a relatively constant blood flow and glomerular filtration rate (GFR) necessary for the clearance of metabolic wastes while maintaining efficient recovery of filtered electrolytes and nutrients by the renal tubule
How are neurotransmitters different from hormones as chemical messengers?
neurotransmitters- short lived hormones-long lived
What are the two primary neurotransmitters used in the ANS? What neuron synthesizes each neurotransmitter and where does each neurotransmitter bind?
norepinephrine (NE) and acetylcholine (ACh) sympathetic neurons secrete NE to adrenergic receptors Parasympathetic neurons secrete ACh to muscarinic cholinergic receptors mAChR
What are the functions of the three main parts of a cell? 1. Nucleus 2. Cytoplasm 3. Plasma Membrane
nucleus-control gene expression and mediate the replication of DNA during the cell cycle cytoplasm-helps fill out the cell and keeps organelles in their place plasma membrane-protects cell from surroundings
How are hormones removed from the body?
once inside the cells, hormones are degraded by enzymes located in lysosomes hormones free in the blood can be broken down and metabolized by enzymes in the blood or enzymes in the liver products of the hormones are excreted through the liver
What are the two states that the voltage-gated K + channels that produce action potentials go through and what triggers them to move between the two states.
open, close depolarize, repolarize
What are organs and organ systems? How are they related to tissues?
organs- a group of tissues in a living organism that has a specific form and function organ systems- organs are grouped together, each system performs a specific task -cells make up tissues, tissues make up organs, organs --make up organ systems the function of an organ system depends on the activity of its organs
How do changes in the following variables affect Hb-O2 binding?pH, temperature, PCO2
pH -Bohr effect -increase in pH increases hemoglobin's affinity for oxygen, causing hemoglobin to pick up oxygen entering your blood from your lungs so it can transport it to your tissues temperature -alters structure of hemoglobin molecule -increased temperature decreases the affinity of hemoglobin for oxygen. -As oxyhemoglobin is exposed to higher temperatures in the metabolizing tissues, affinity decreases and hemoglobin unloads oxygen. PCO2 -affects the affinity of hemoglobin for oxygen because CO2 reacts reversibly with amino acid groups in hemoglobin to form carbaminohemoglobin -reducing the affinity of the binding sites for oxygen molecules.
What is pH and why is it important to regulate it within a narrow range in human bodies?
pH expresses acidity or alkalinity of a solution, where 7 is neutral lower values more acidic, higher values more basic it needs to stay in a normal range in order for cells to survive
If plasma calcium levels dip below their threshold, explain the impact on the following hormones: parathyroid hormone & calcitonin
parathyroid -promotes calcium release from bone, calcium absorption by intestine and calcium reabsorption by kidney tubules -raises blood calcium levels -stimulates vitamin d synthesis calcitonin -promotes calcium depostion in bone -lowers blood calcium levels
Are there ever times when alveolar pressure is equal to atmospheric pressure? What does this mean for air flow?
pause between breaths/end of inspiration/end of expiration means no air flow
Compare and contrast peripheral and central chemoreceptors that contribute to ventilation.
peripheral chemoreceptors - in carotid bodies -PO2, PCO2, pH in arterial blood -faster response time, instantaneous central chemoreceptors -in medulla oblongata -Hydrogen ion concentration in CFS -protected by BBB -slower response, maintain steady state of CO2
What is the difference between peristalsis and segmentation? What is the function of each?
peristalsis the involuntary constriction and relaxation of the muscles of the intestine or another canal, creating wave-like movements that push the contents of the canal forward. segmentation mixes food with digestive juices and facilitates absorption. contractions of the circular muscles
What are three main ways to categorize smooth muscle?
phasic, tonic, rhythmic
What is excitation-contraction coupling in skeletal muscles? a. What would happen if there were no T-Tubules? b. Can skeletal muscle activation be inhibited by a somatic motor neuron?
physiological process of converting an electrical stimulus to a mechanical response. It is the link (transduction) between the action potential generated in the sarcolemma and the start of a muscle contraction. if there were no t tubules the reaction would be slow
How and where in the body does exchange of fluid and materials with the external environment occur?
plasma membrane
What is the physiological significance of the plateau and the steep portions of the Hb-O2 dissociation curve?
plateau -Arterial blood -Needs extremely high pressure to add more oxygen-90-100% saturation steep -A small decrease in PO2causes a relatively large release of oxygen-75-35% saturation
What is the direction of the resting membrane potential (V Rest) in cells? In other words, is the inside of the cell more positive or negative than the outside of the cell?
positive outside negative inside
Describe how preganglionic neurons and postganglionic neurons differ? Where is the preganglionic neuron body located in the spinal cord and where does it exit the spinal cord? What is an autonomic ganglia and what structures are located there?
preganglionic-before ganglion, release ACh postganglionic- have nAChR receptors
Explain the signal transduction mechanism of a steroid hormone and address how quickly changes in protein synthesis occurs and how long the effects can last.
process by which an extracellular signal molecule activates a receptor that in turn alters intracellular molecules to create a response steroid goes into the cell and goes to the nucleus and changes that cells DNA so it increases or decreases protein synthesis..build up proteins for growth..proteins are the backbone of everything so when you make a receptor you need them for growth
What are the primary functions of the large intestine?
recovery of water and electrolytes formation and storage of faeces fermentation of some of the indigestible food matter by bacteria.
Why do action potentials only travel in one direction physiologically?
refractory period sodium channels have a mechanism that avoids "back propagation" of the action potential, which would result in a confused signal.
Why is the resting membrane potential considered a steady state rather than an equilibrium state?
resting membrane potential is considered a steady state because it requries energy to maintain its state
Which regions of the eye are responsible for bending light for further processing? What is phototransduction and where in the eye does phototransduction occur?
retina, phototransduction occurs in retina rods/cones light is converted into electrical signals in the rod cells, cone cells and photosensitive ganglion cells of the retina of the eye.
What are the two types of photoreceptors and what is their adequate stimulus? What is the role of rhodopsin?
rods and cones rods-dark cones-light Rhodopsin- pigment found in the rods of the retina and is a G-protein-coupled receptor (GPCR). It belongs to opsins. is extremely sensitive to light, and thus enables vision in low-light conditions
Explain the signal transduction mechanism of a chemical that binds with a membrane-bound receptor and address how quickly changes in protein synthesis occur and how long the effects can last. What classification of chemical messenger requires a membrane-bound receptor at the target cell?
signaling a receptor to affect something binds with a peptide/protein changes occur quickly and decrease quickly which stimulates the cell by attatching to outside of cell then changes cells electrical properties classification is a peptide protein
What general processes govern how oxygen and carbon dioxide move between alveolar air and blood? Which factors contribute to the rate of transport in simple diffusion?
simple diffusion factors that contribute to rate of transport -Surface area -concentration gradient -barrier permeability (pulmonary edema) -distance
.Compare the function of neural input to the respiratory skeletal muscles to the function of neural input to cardiac contractile/muscles fibers?
skeletal muscle:pacemaker cells, you can control respiratory skeletal muscles, diaphragm + breathing cardiac contractile: makes its own action potential
Describe what happens during a two-point discrimination test. Why is this important when considering the amount of body part representation in the sensory cortex?
small receptive fields are found in sensitive areas, two stimuli activate seperately, perceived as distinct
Trace the general pathway of a somatosensory signal to the somatosensory cortex. In what part of the spinal cord does afferent/sensory information synapse?
somatic receptor, spinal cord, medulla, thalamus, somatosensory cortex
What are the special senses and what are the somatic senses? What are the four major sensory receptor classes and their adequate stimulus?
somatic senses -touch -proprioception -temperature -nociception Special senses -vison -hearing -balance -equilibrium -taste and smell Sensory receptors -merkel:pressure -meissner:stroking movement -pacinian:vibration -ruffini:skin stretch photoreceptor chemoreceptor thermoreceptor mechanoreceptor
How is equilibrium different from steady state? Which term should be used to describe homeostasis?
steady state-remains constant over time but requires continual work equilibrium-stable over time but no energy or work is required to maintain the condition homeostasis is equilibrium
What are the neurotransmitters and receptors in the two divisions of the autonomic efferent neural pathways
sympathetic- nicotinic cholergenic receptor ACH adrenergic receptor NE parasympatheitc-nicotinic cholergic receptor ACh muscarinic cholergic ACh
What are the 'normal' values for diastolic and systolic blood pressure and what might be a reason for an abnormally high pulse pressure?
systolic between 90-120 diastolic between 60-80 stiffness of the aorta, the largest artery in the body. The stiffness may be due to high blood pressure or fatty deposits damaging the walls of the arteries, leaving them less elastic
What is the difference between temporal and spatial summation of post-synaptic potentials?
temporal-time spatial-space
What does mean arterial pressure (MAP) indicate and why is this measurement important?
the measurement that explains the average blood pressure in a person's blood vessels during a single cardiac cycle. Mean arterial pressure is significant because it measures the pressure necessary for adequate perfusion of the organs of the body
Why is ventricular myocardium thicker than atrial myocardium? Why is the left ventricle muscle thicker than the right ventricle?
this muscle must pump all blood returning to the heart into the lungs for oxygenation
Beyond transporting air in and out of the gas exchange airways, what are the functions of the conducting airways?
to conduct, clean, warm, and moisten the air. form pump to create a pressure gradient
What is the role of the cardiovascular control center in the response to a sudden drop in blood pressure? What other brain regions send information to the CVCC?
to ensure adequate blood flow to brain and heart by maintaining sufficient MAP
Explain the difference between a tonic and phasic receptor and give an example of each type.
tonic-adapts slowly phasic-adapts rapidly
What are two pathways via which substances may cross an epithelium?
transcellular (across) or paracellular(between)
What is epithelial transport and where in the body does it occur?
transport across an epithelial cell can be divided into those that do not require a protein, and those that are protein-mediated. There are two routes for transport of molecules and ions across the epithelium of the gut: Across the plasma membrane of the epithelial cells (transcellular route) Across tight junctions between epithelial cells (paracellular route)
What are the functional and structural differences between troponin and tropomyosin?
tropomyosin -elongated protein polymer -blocks the attachment site for the myosin crossbridge, thus preventing contraction. troponin -complex of 3 proteins
. Define vasoconstriction versus vasodilation and explain how they affect blood pressure. What is their relationships with total peripheral resistance?
vasoconstriction-the constriction of blood vessels, which increases blood pressure. vasodilation-the widening of blood vessels decreases blood pressure
Where is each type of ion channel located in a neuron and what types of signals (graded potentials or action potentials) does each generate? a. leak channels b. voltage gated channels c. ligand gated d. mechanically/stretch gated
voltage-gated channels- found on the axon hillock, all along unmyelinated axons, and at the nodes of Ranvier in myelinated axons. Ligand-gated channels- located at sites of synaptic contact are found predominantly on dendritic spines, dendrites and somata of nerve cells, or neurons.
What is the body's main solvent?
water
What is local current flow and what role does it play in graded potential and action potential propagation or conduction?
when a piece of the membrane reaches action potential. It becomes depolarized enough to cause the piece of membrane next to it to also depolarize enough to reach action potential. Sending an action potential across the cell membrane.
How does the sympathetic nervous system impact cardiac contractile cells?
•NE to β1receptor (cAMPsecond messenger system) increases ion flow•Opens more Ifand T-type Ca2+ channels at SA node and AV node•More rapid cation entry speeds up the rate of depolarization•Enhance conduction through AV node•Required for HR above 90-100 bpm•Influences ventricular contractile fibers
Briefly map the events of an electrocardiogram (P wave, QRS complex and T wave) onto their corresponding electrical events.
•P wave: ECG begins with atrial depolarization, atrial contraction blood is pushed from the atria into right and left ventricles (AV valves)• P-R segment signal travels through AV node and AV bundle to apex of ventricles• QRS Complex: ventricular depolarization, ventricular contraction begins and continues through T wave-blood pushed out to pulmonary artery (right side) and aorta (left side)•Atrial repolarization• Heart rate: R-R interval
