Bi 233 Exam 2

When blood pressure or blood volume are too high, ____ will be released and will stimulate the kidney to ____ GFR so that blood volume & pressure will decline. Correct! ANP; increase renin; decrease Angiotensin II; increase epinephrine; decrease

ANP; increase

Air flow and blood flow are governed by the same principles: flow occurs when pressure gradients can overcome resistance. And like in the cardiovascular system, resistance to airflow is almost entirely altered by changes in diameter of the conduits (in the case of the respiratory system, these important conduits are the bronchioles). What would happen to airflow into an alveolus when the bronchiole serving that alveolus constricts? Airflow would increase into the alveolus Correct! Airflow would decrease into the alveolus

Airflow would decrease into the alveolus Right! Downstream of the constriction airflow will decrease. Controlling airflow into alveoli is called alveolar ventilation. Alveolar ventilation is closely matched to blood flow into the pulmonary capillaries (perfusion of the pulmonary capillaries) by a special autoregulatory mechanism. That is, when an alveolus has lots of fresh oxygen and relatively little carbon dioxide, the pulmonary capillary bed (arteriole) serving that alveolus opens up to increase flow (high ventilation is matched by high perfusion). Should the alveolus be full of carbon dioxide and poor in oxygen, the arteriole/capillary restricts blood flow (poor ventilation is met with poor perfusion). This helps increase efficiency in the respiratory system so that we can maximize exchange surfaces.

What would happen to airflow into an alveolus when the bronchiole serving that alveolus constricts? Airflow would increase into the alveolus Correct! Airflow would decrease into the alveolus

Airflow would decrease into the alveolus Right! Downstream of the constriction airflow will decrease. Controlling airflow into alveoli is called alveolar ventilation. Alveolar ventilation is closely matched to blood flow into the pulmonary capillaries (perfusion of the pulmonary capillaries) by a special autoregulatory mechanism. That is, when an alveolus has lots of fresh oxygen and relatively little carbon dioxide, the pulmonary capillary bed (arteriole) serving that alveolus opens up to increase flow (high ventilation is matched by high perfusion). Should the alveolus be full of carbon dioxide and poor in oxygen, the arteriole/capillary restricts blood flow (poor ventilation is met with poor perfusion). This helps increase efficiency in the respiratory system so that we can maximize exchange surfaces.

Why did heart rate increase with activity? Hormones are released with exercise some of which affect heart rate More oxygen was needed Cardiac output must increase with exercise Working muscles require more blood flow

All of the above

Why must GFR be kept at a constant level? So that you filter your blood to remove wastes So that you can maintain blood pressure So that you can maintain the proper ion concentration in your blood Correct! All of the above

All of the above Right! A balanced rate of glomerular filtration ensures that your blood gets filtered at a rate which your nephron tubules can work with the filtrate inside of them. If the GFR is too high, the filtrate passes through the nephron too fast and solutes (& water) do not get reclaimed (reabsorbed). If GFR is too low, too much volume get reabsorbed and waste products do not leave the body. Maintaining blood composition and volume factor into the maintenance of blood pressure.You must maintain an appropriate rate of glomerular filtration to constantly adjust your blood levels of ions and wastes. If you do not filter your blood, body pH is not maintained and ionic composition changes. These in turn affect cellular functions such that neurons may not fire or the heart may not beat. Enzymes in the body also need a steady environment in which to work.

Why should you love your kidney and treat it right? Because it controls blood pressure Because it determines blood viscosity Because it prevents anemia Correct! All of the above

All of the above Right! The kidney detects low blood oxygen levels and blood pressure. When blood oxygen is too low (anemia), it releases erythropoietin (EPO), a hormone that increases red blood cell production. The more red blood cells produced, the greater the blood viscosity.When blood pressure is too high, the kidney can correct the problem by producing more urine. Urine is really just filtered blood and so with increased urine production, there is less blood volume and therefore less blood pressure. What is very amazing about this pressure/urine volume relationship is that it can work independently of hormones as a simple pressure filter. The higher the pressure, the more urine produced; the more urine made, the lower the blood volume will drop and therefore further reduce blood pressure. This is a life long mechanism for regulating blood pressure. Of course this can work in reverse such that if blood pressure is too low, less urine is made and blood volume with rise (coupled with some fluid intake as well).

Hemoglobins' affinity for oxygen is directly related to how much oxygen is actually currently held by the hemoglobin. So, if hemoglobin has high oxygen saturation, hemoglobin's affininty for oxygen is high. What do you think happens to hemoglobin's affinity for oxygen after it moves through the systemic capillaries? Correct! As the RBC moves through the systemic capillary, hemoglobin's affinity for oxygen decreases. As the RBC moves through the systemic capillary, hemoglobin's affinity for oxygen increases. As hemoglobin moves through the systemic capillary, hemoglobin's affinity for oxygen stays the same.

As the RBC moves through the systemic capillary, hemoglobin's affinity for oxygen decreases. Correct! Hemoglobin is a protein molecule that behaves differently in different situations. When oxygen level changes, hemoglobin's affinity for oxygen changes. When oxygen is very abundant in the environment (high pO2), hemoglobin binds oxygen very tightly due to the way the molecule is shaped. When environmental oxygen is very low (low pO2), hemoglobin is shaped differently and does not bind oxygen as readily. In the case of the body, when hemoglobin travels through the pulmonary capillary it moves into a very high oxygen environment, causing it to have a high oxygen affinity. When the hemoglobin moves through the systemic capillary, it becomes exposed to a lower oxygen environment and then decreases its affinity for oxygen. This loss of affinity from a high state (bound with lots of oxygen) to a low state (less oxygen bound) causes oxygen to be released to the tissues.

Hemoglobins' affinity for oxygen is how much oxygen is actually currently held by the hemoglobin. So, if hemoglobin has high oxygen saturation, hemoglobin's affininty for oxygen is high. What do you think happens to hemoglobin's affinity for oxygen as it moves through the systemic capillaries? Correct! As the RBC moves through the systemic capillary, hemoglobin's affinity for oxygen decreases. As the RBC moves through the systemic capillary, hemoglobin's affinity for oxygen increases. As hemoglobin moves through the systemic capillary, hemoglobin's affinity for oxygen stays the same.

As the RBC moves through the systemic capillary, hemoglobin's affinity for oxygen decreases. Correct! Hemoglobin is a protein molecule that behaves differently in different situations. When oxygen level changes, hemoglobin's affinity for oxygen changes. When oxygen is very abundant in the environment (high pO2), hemoglobin binds oxygen very tightly due to the way the molecule is shaped. When environmental oxygen is very low (low pO2), hemoglobin is shaped differently and does not bind oxygen as readily. In the case of the body, when hemoglobin travels through the pulmonary capillary it moves into a very high oxygen environment, causing it to have a high oxygen affinity. When the hemoglobin moves through the systemic capillary, it becomes exposed to a lower oxygen environment and then decreases its affinity for oxygen. This loss of affinity from a high state (bound with lots of oxygen) to a low state (less oxygen bound) causes oxygen to be released to the tissues.

How are total cross-sectional of vessels and velocity of blood flow related? As total cross-sectional area of vessels increases, velocity of blood flow increases Correct! As total cross-sectional area of vessels increases, velocity of blood flow decreases

As total cross-sectional area of vessels increases, velocity of blood flow decreases

Why is resting heart rate lower than the automatic depolarization rate of the SA node? Correct! At rest, the vagus nerve causes SA node cells to hyperpolarize At rest, sympathetic cardiac nerves release neurotransmitter Venous return is high The Bainbridge reflex dominates the heart at rest

At rest, the vagus nerve causes SA node cells to hyperpolarize Right! The Vagus nerves synapse on the SA node and AV node. They release acetylcholine (Ach) that binds to chemically gated channels on these cells. The Ach triggers potassium release from the SA & AV node cells, causing the SA node to reach threshold less often and fire action potentials less often (a slower heart rate). Sympathetic activation increases heart rate by allowing calcium entry into the SA node cells (increases contractility too through the same mechanism). Venous return is low at rest. The Bainbridge reflex is triggered when increased venous return activates stretch receptors in the right atrium. These receptors communicate with the cardioacceleratory center in the brainstem which then activates sympathetic nerves to increase heart rate. Although this reflex is activated during inhalation when thoracic pressure increases blood flow into the right atrium, it would not lower the heart rate and it is not dominant.

During heavy exercise, cardiac output increases dramatically, although pressure may only increase modestly. How is this possible? Correct! Because resistance increases at some vessels and decreases at others Because all systemic vessels dilate Because all systemic vessels constrict Because resistance in the systemic circulation increases

Because resistance increases at some vessels and decreases at others During exercise, autoregulation to active skeletal muscles causes arterioles serving the muscle capillary beds to dilate and precapillary sphincters to open. Now that blood can find more vessels to fill as arterioles and sphincters open, decreasing resistance and increasing flow to tissues, pressure in the aorta may fall (more active muscle mass would increase number of dilating arterioles and magnitude of pressure drop). Such a drop in pressure would trigger baroreceptor reflexes that would lead to sympathetic activation. Sympathetic activation would trigger vasoconstriction in the systemic vessels except for those serving tissues that are working hard; in such tissues, autoregulation overcomes the sympathetic vasoconstriction and the vessels remain open. The vessels that do constrict (those serving gut tissue), act to increase pressure and shunt blood to other tissues that have decreased resistance. At the same time, the heart works harder (increases HR and contractility due to the sympathetic stimulation) and increases CO. It should seem that the increased CO should increase pressure radically and yet, the balance of the increased CO, vasoconstriction from sympathetic signals and vasodilation from autoregulation results in a high CO, some systemic pressure increase, but little change in the systemic peripheral resistance. In fact, peripheral resistance may even drop overall. Imagine if you needed to increase CO to deliver more blood, but you did not alter resistance (vessels could not change diameter). Pressure would increase dramatically and tear vessels. By altering resistance, we can have huge gains in CO with only a modest pressure increase.

Why can the pulmonary capillary blood achieve the same PO2 as alveolar air? Correct! Because there is an overabundance of oxygen in the alveoli compared to the pulmonary arteries Because the alveoli contain more total gas pressure than the blood

Because there is an overabundance of oxygen in the alveoli compared to the pulmonary arteries Yes! Air is a mixture of gases. Their total pressure (760 mmHg) is a sum of the pressures exerted by each gas. Partial pressure is the pressure exerted by a single gas inthe mixture of gases. The movement of a gas is related to its individual partial pressure; gases move from a region of higher partial pressure to a region of lower partial pressure, down a partial pressure gradient.

Why do the lungs expand during inspiration? Correct! Because they are "pulled" open by the pleura Because the diaphragm attaches directly onto the lungs and pulls the lungs down Because positive intrapleural pressure "pulls" them open Because the intercostal muscles attach directly onto the lungs and pull the lungs outward

Because they are "pulled" open by the pleura Increasingly negative intrapleural pressure generated by the expansion of the rib cage and inferior thoracic cavity during inhalation (inspiration) pulls the lungs open. Surface tension between the visceral and parietal pleura create a suction. If the parietal pleura (attached to inside thoracic cavity) move away from the lung, they generate a greater suck on the visceral pleura. The visceral pleura are attached to outside of the lung, and thus, when the visceral pleura moves, so does the lung. No muscles directly insert onto the lungs.

Why do the lungs expand during inspiration? Because the intercostal muscles attach directly onto the lungs and pull the lungs outward Because the diaphragm attaches directly onto the lungs and pulls the lungs down Because positive intrapleural pressure "pulls" them open Correct! Because they are "pulled" open by the pleura

Because they are "pulled" open by the pleura Right! Increasingly negative intrapleural pressure generated by the expansion of the rib cage and inferior thoracic cavity during inhalation (inspiration) pulls the lungs open. Surface tension between the visceral and parietal pleura create a suction. If the parietal pleura (attached to inside thoracic cavity) move away from the lung, they generate a greater suck on the visceral pleura. The visceral pleura are attached to outside of the lung, and thus, when the visceral pleura moves, so does the lung. No muscles directly insert onto the lungs.

Why are women more prone to bacterial infections of the urinary tract than men? Correct! Because women have shorter urethras Because women have longer ureters Because women have larger bladders relative to total body mass Because bacteria from the ovaries travel to the bladder

Because women have shorter urethras Yes! With the much shorter urethras in women, contaminating bacteria from the external world can move into the urinary tract. Inflammation of the urinary tract attempts to combat the bacteria, causing pain. Bacteria can also move into the bladder or even up the ureters to cause kidney infections.

Why is it acceptable to make CO2 in RBCs found in pulmonary capillary blood? Because you can convert that CO2 back in to H+ & HCO3- Correct !Because you can release CO2 into the alveoli and remove it from the body

Because you can release CO2 into the alveoli and remove it from the body

Suppose your blood has too low pH. How can your body correct this? By holding your breath (decreasing respiratory rate) By secreting bicarbonate ions into the filtrate Correct! By increasing depth and rate of pulmonary ventilation By reabsorbing H+ ions from the filtrate

By increasing depth and rate of pulmonary ventilation Right! The respiratory system can correct acidosis (too low pH of the blood) by increasing respiratory rate and depth to eliminate more CO2 from the body. Doing this causes more H+ ions not to be free but to combine with HCO3- to make H2CO3 which then makes more CO2 and H20 at the lung. The CO2 is then removed from the system leaving only water. All of the other options would cause more H+ to remain in the body thus making the blood more acidic.

What is responsible for pushing fluid out across the capillary wall into the interstitial fluid? Correct! Capillary hydrostatic pressure being greater than interstitial fluid hydrostatic pressure Capillary colloid osmotic pressure being greater than interstitial fluid osmotic pressure

Capillary hydrostatic pressure being greater than interstitial fluid hydrostatic pressure

Look at the equation in Model 2: Inside the RBC, what happens to carbonic anhydrase activity and bicarbonate production if H+ ion concentration rises? Carbonic anhydrase makes more HCO3- Correct! Carbonic anhydrase makes less HCO3-

Carbonic anhydrase makes less HCO3-

During exercise, what happens to the heart? Correct! Cardiac output increases to increase blood delivery to exercising tissues. HR increases, but there is less time for ventricular filling, so stroke volume and cardiac output decrease. Stroke volume decreases which leads to a decreased cardiac output. Blood flow through the coronary arteries decreases because more blood is moving through the aorta.

Cardiac output increases to increase blood delivery to exercising tissues. Right! During exercise there is increased demand at the skeletal muscles for oxygen and nutrients. Receptors detecting muscle activation (proprioceptors) as well as changing levels of blood oxygen and carbon dioxide (reflecting increased usage/production at the tissues) cause the heart to pump more blood each minute. This is an increase in cardiac output to match blood delivery to tissue demands. Also, exercising muscles push more blood through the systemic veins - this is called an increase in venous return. This increased volume into the heart (increased venous return) also leads to increased SV out of the heart (due to the Frank-Starling law of the heart) and thus increases cardiac output. Cardiac output must increase during exercise. Any response that claims that cardiac output decreases is wrong here. While HR does increase during exercise, and this does allow less time for ventricular filling, there is also an increase in heart contractility associated with exercise (due to sympathetic activation). This causes SV to remain the same (or perhaps become even higher as the heart squeezes harder and ESV declines) and therefore the combination of increased HR & same or higher SV leads to increased CO. Blood flow through the coronary arteries increases when the heart works harder.

Which of the following will most readily trigger an increase in respiration rate and depth? Femoral venous hemoglobin saturation = 80% Correct! Carotid PCO2 = 47 mmHg Pulmonary venous PCO2 = 40 mmHg Aortic PO2 = 90 mmHg Jugular PO2 = 40 mmHg

Carotid PCO2 = 47 mmHg Right! Femoral venous hemoglobin saturation = 80% is normal, maybe even a little high for a systemic vein according to what we discussed in lecture. Carotid PCO2 = 47 mmHg is too high, this should be =40 mmHg. Very small increases in systemic arterial PCO2 trigger increases in respiration rate to remove CO2 from the body. Pulmonary venous PCO2 = 40 mmHg - this is normal for blood entering the pulmonary capillary for oxygen pickup. Aortic PO2 = 90 mmHg - this is a little low, but hemoglobin is still nearly 100% saturated and this will not alter respiration rate. Jugular PO2 = 40 mmHg - this is normal for blood leaving a tissue at rest.

As you move down the bronchial tree (from the trachea toward the alveoli), what changes do you observe. Dimeter increases Smooth muscle decreases Correct! Cartilage decreases

Cartilage decreases

You have been gardening in a squatting position for 20 minutes. You stand up quickly to answer the phone and feel light headed. After about 10 seconds more you feel fine again. What was the cause and correction of your faint feeling? Cause: low blood pressure due to too much vasodilation Correction: increased angiotensin II formation (i.e. hormone activation) that caused massive vasoconstriction Cause: low blood pressure due to low blood volume Correction: kidney made less urine, thus increasing blood volume and blood pressure Correct Answer Cause: low blood pressure due to too low cardiac output Correction: sympathetic nervous system activation from a baroreceptor signal Cause: increased blood pressure due to too high blood volume Correction: ANP secretion (hormone) from heart to reduce blood volume & thus blood pressure

Cause: low blood pressure due to too low cardiac output Correction: sympathetic nervous system activation from a baroreceptor signal Squatting for a while reduces venous return from the lower limb because the veins are compressed and cannot refill with blood or send blood toward the heart (try this and look at your feet after 20 minutes of squatting). Reduced venous return will cause reduced cardiac output (Frank-Starling law) and reduced blood pressure (flow = pressure change/R). The cause of your faint feeling was reduced blood flow to the brain due to reduced blood pressure. This reduction in blood pressure associated with posture changes (orthostatic changes) is detected by baroreceptors in the carotid arteries. The correction mechanism to fix the too low blood pressure is vasoconstriction of some peripheral arteries and increased cardiac output, both due to increased sympathetic activation. The information from baroreceptors in the aorta and carotid arteries is relayed to the medulla oblongata cardiovascular centers. When too low pressure is detected, these centers direct increased sympathetic activity to blood vessels and the heart. Increased sympathetic activity increases cardiac output, thus increasing flow in the system and increasing blood pressure overall. The increased sympathetic activation to blood vessels causes increased vasoconstriction of some systemic vessels that leads to an increase in pressure overall (blood vessels to brain escape this vasoconstriction to some degree). These corrective mechanisms can increase systemic blood pressure within 5-10 seconds. Angiotensin II and ANP are chemicals that adjust blood pressure but they do so in a matter of minutes or hours. Angiotensin II production is triggered when blood flow to the kidney is reduced. Angiotensin II causes widespread vasoconstriction and increases in blood volume through decreased urine production (using the hormones aldosterone & ADH). ANP is atrial natriuretic peptide - a hormone released from the heart when pressure is too high. ANP causes increased urine formation - the more urine made, the lower the blood volume will become. Reducing blood volume will reduce blood pressure. The kidney can control blood pressure by adjusting blood volume as a pressure filter. In this manner, the kidney takes hours to days to correct blood pressure, not seconds as indicated here.

What factor determines air flow into or out of the lung? (Assume no factor is 0) Atmospheric pressure (a number of mmHg) Intrapulmonary pressure (a number of mmHg) Correct! DIfference in pressure between the atmospheric pressure and intrapulmonary pressure

Difference in pressure between the atmospheric pressure and intrapulmonary pressure

What does a blood pressure of 120/70 tell you? At the end of ventricular diastole, the left ventricle generates 70 mmHg During atrial systole, the left ventricle generates 120 mmHg During sympathetic activation, the elastic arteries generate 120 mmHg Correct! During ventricular systole, the left ventricle generates more than 120 mmHg The aortic semilunar valve closes when aortic pressure reaches 120 mmHg

During ventricular systole, the left ventricle generates more than 120 mmHg Right! Blood must flow from high pressure to low. A blood pressure of 120/70 means that during ventricular systole, when blood is leaving the ventricles and distending the aorta and elastic systemic arteries, the blood pressure in the measured artery is 120 mmHg. During ventricular diastole, there is no further ejection and the elastic arteries recoil. The arteries recoil, keeping pressure on the blood as its volume decreases (the blood is moving away from the SL valve into the systemic circuit). The diastolic pressure is the lowest pressure recorded in the arteries and it occurs just before the next ejection begins and more blood is ejected into the aorta, distending it again (here, 70 mmHg). In order to initiate ventricular ejection into the aorta, the left ventricle must at first overcome 70 mmHg, but as volume continues to flow into the aorta, the pressure rises up to 120 mmHg. At peak systole, to continue blood flow into the aorta, ventricular pressure must exceed 120 mmHg. In this way diastolic pressure represents the pressure that must first be overcome to begin ejection and systolic pressure represents the peak pressures required to sustain ejection at the height of systole.

At the time when you measure systolic blood pressure, both atria and both ventricles are in systole. True Correct! False

False

Autoregulation is a homeostatic mechanism that regulates blood pressure in the aorta. True Correct ! False

False

If the liver could not produce enough albumin, the tissues would become dehydrated. (before compensatory mechanisms corrected the problem) True Correct! False

False

True or False? Sympathetic stimulation increases heart rate but decreases stroke volume due to less time for ventricular filling. True Correct! False

False

When two vessels have the same blood flow per minute, they also have the same blood velocity per minute. True Correct! False

False

Compare this image to the baseline in Model 1. How would GFR change in this image relative to baseline? Correct! GFR would increase GFR would decrease GFR would not change

GFR would increase

Compare this image to the baseline in Model 1. How would glomerular hydrostatic pressure change in this image relative to baseline? Correct! Glomerular hydrostatic pressure would increase Glomerular hydrostatic pressure would decrease Glomerular hydrostatic pressure would not change

Glomerular hydrostatic pressure would increase

What does hemoglobin release when it binds O2? Correct! H+ Cl- HCO3- H2O

H+

What happens to hemoglobin's affinity for oxygen when levels of CO2 increase? Correct! Hemoglobin's affinity for oxygen decreases Hemoglobin's affinity for oxygen increases Hemoglobin's affinity for oxygen does not change

Hemoglobin's affinity for oxygen decreases Nice! When the level of CO2 increases (or conditions become acidic or temperature increases), hemoglobin's affinity for oxygen decreases. This means that hemoglobin holds on to oxygen less tightly, thus releasing it more readily to a hungry tissue. This is also a right shift in the oxygen-hemoglobin dissociation curse and is beneficial because it allows more oxygen delivery for the same level of PO2.It would seem that this lower affinity of hemoglobin for oxygen would be bad because it would limit how much O2 could bind in the lung. But remember that hemoglobin is fully saturated at low levels of PO2 naturally (as low at 70 mmHg) and the high level of CO2 is erased at the pulmonary capillary when CO2 diffuses into the alveoli and is removed from the blood. So, while the hemoglobin curve shifts right when the hemoglobin is in the systemic capillaries, it shifts to the left again when the hemoglobin is in the pulmonary capillaries.

What happens to hemoglobin's affinity for oxygen when blood becomes more acidic? Correct! Hemoglobin's affinity for oxygen decreases Hemoglobin's affinity for oxygen increases Hemoglobin's affinity for oxygen does not change

Hemoglobin's affinity for oxygen decreases Nice! When the level of CO2 increases (or conditions become acidic or temperature increases), hemoglobin's affinity for oxygen decreases. This means that hemoglobin holds on to oxygen less tightly, thus releasing it more readily to a hungry tissue. This is also a right shift in the oxygen-hemoglobin dissociation curse and is beneficial because it allows more oxygen delivery for the same level of PO2.It would seem that this lower affinity of hemoglobin for oxygen would be bad because it would limit how much O2 could bind in the lung. But remember that hemoglobin is fully saturated at low levels of PO2 naturally (as low at 70 mmHg) and the high level of CO2 or H+ is erased at the pulmonary capillary when CO2 diffuses into the alveoli and is removed from the blood. So, while the hemoglobin curve shifts right when the hemoglobin is in the systemic capillaries, it shifts to the left again when the hemoglobin is in the pulmonary capillaries.

Which of the following will INCREASE respiratory rate? Correct! High carotid PCO2 High carotid PO2 Low aortic PCO2 High jugular PCO2

High carotid PCO2 Yes! If there is too much CO2 in the systemic arterial blood, then there was not enough removal of CO2 by the lungs. The chemoreceptors in the carotid bodies & aorta detect this high systemic arterial PCO2 and relay the information to the respiratory centers of the brainstem. Also, central chemoreceptors located in the medulla oblongata receive CO2 from systemic arteries. If too much CO2 moves across into the blood brain barrier, H+ ions form. These ions cannot be buffered (due to low protein composition of the cerebrospinal fluid) and the central chemoreceptors are triggered. The brainstem centers (in pons and medulla oblongata) are then stimulated to increase respiratory rate to remove more CO2 from the body.We do not monitor the composition of the systemic venous blood (i.e. Jugular vein) because the blood in these vessels has not reached the lungs for adjustment. Not matter how high the systemic venous blood CO2 level becomes, If the lungs are performing adequately, then enough CO2 is removed and there is no cause to increase ventilation rate.Too low O2 can stimulate increased respiration rate, but only when O2 levels reach less than 60 mmHg PO2 in systemic arteries.

Based on your understanding of capillary dynamics, which of the following would you expect will increase glomerular filtration rate (fluid leaving the first capillary in the nephron)? Correct! Increased blood plasma volume Increased blood plasma protein concentration Increased blood plasma ion concentration

Increased blood plasma volume

How did systolic blood pressure respond to light activity? Decreased from resting Stayed the same as resting in all cases Correct! Increased or stayed the same from resting

Increased or stayed the same from resting

Regarding cardiac output: Increased heart rate will always lower cardiac output because the ventricles fill less People with slow heart rates always have low cardiac outputs Correct! Increased venous return increases stroke volume and cardiac output Increasing heart rate will always increase cardiac output

Increased venous return increases stroke volume and cardiac output Increased heart rate will always lower cardiac output because the ventricles fill less. - Not true. Although EDV may decrease, if you increase contractility, the ventricle will squeeze harder and eject more, lowering the amount left behind (ESV). This may keep SV normal or even increased, thus maintaining or increasing CO. Furthermore, increased exercise may increase venous return, so that even though filling time is less, more volume may come back, maintaining EDV. People with slow heart rates always have low cardiac outputs. - Not true. Slower heart rate allows more filling time and a higher EDV. If EDV is higher, SV will be higher due to the Starling law of the heart. Increased venous return increases stroke volume and cardiac output. True. This is the Starling law of the heart. When more volume comes into the ventricle, that volume stretches the muscle into better interaction between actin and myosin. This better interaction means a more forceful contraction. This more forceful contraction leads to more volume being ejected (a higher SV) which means a higher CO. Increasing heart rate will always increase cardiac output. - Not true. If HR is high, but SV is low, CO will not increase. CO = HR x SV. This type of thing may happen when someone loses a lot of blood (hemorrhage). The heart rate increases, but with a low stroke volume (due to low blood volume) they may not be able to maintain CO needed to maintain life.

According to our worksheet, what leaves the capillary through intercellular clefts and enters the interstitial fluid? Correct! Ions, glucose, water Plasma proteins Both plasma proteins and ions, glucose, water

Ions, glucose, water

Which of the following accurately describes the site of external respiration? Correct! It allows easy diffusion of gases between the alveoli and the body. It is the trachea, bronchi and bronchioles. It is very thick and covered with a thin layer of mucous. It is composed of tissue cell membranes, a thin layer of connective tissue and the wall of a systemic capillary.

It allows easy diffusion of gases between the alveoli and the body. Right! The respiratory membrane is the site of external respiration. It is made of the pulmonary capillary wall, a thin amount of connective tissue and the wall of an alveolus. It is free of cilia although it does have a little bit of fluid lining it. The respiratory membrane is very thin to allow easy diffusion of gases - in pneumonia the respiratory membrane becomes thickened and it is difficult to load the blood with oxygen because gases cannot diffuse into the blood.

Which of the following accurately describes the site of external respiration? Correct! It allows easy diffusion of gases between the alveoli and the body. It is the trachea, bronchi and bronchioles. It is very thick and covered with a thin layer of mucous. It is composed of tissue cell membranes, a thin layer of connective tissue and the wall of a systemic capillary. It is pseudostratified ciliated columnar epithelium.

It allows easy diffusion of gases between the alveoli and the body. Right! The respiratory membrane is the site of external respiration. It is made of the pulmonary capillary wall, a thin amount of connective tissue and the wall of an alveolus. It is free of cilia although it does have a little bit of fluid lining it. The respiratory membrane is very thin to allow easy diffusion of gases - in pneumonia the respiratory membrane becomes thickened and it is difficult to load the blood with oxygen because gases cannot diffuse into the blood.

In Model 3, in the systemic capillaries, what happens to the H+ ion created by the conversion of CO2 (+H2O) to HCO3? Correct! It becomes attached to hemoglobin, releasing an O2 to the tissue It combines with HCO3- to make more CO2 at the systemic capillary It is exported to the plasma in exchange for a Cl-

It becomes attached to hemoglobin, releasing an O2 to the tissue

In Model 3, in the pulmonary capillary, what happens to the H+ ion when O2 binds with hemoglobin? Correct! It binds with HCO3- to make CO2 (& H2O) It re-attaches to hemoglobin again to release O2 back to the alveoli It is removed from the RBC into the plasma in exchange for Cl-

It binds with HCO3- to make CO2 (& H2O)

For a single cardiac cycle, why does sympathetic activation increase stroke volume? It increases EDV It increases ESV It decreases EDV Correct! It decreases ESV

It decreases ESV Right! Sympathetic activation increases contractility of the heart, making ventricular systole more effective. This lowers the volume left in the ventricle at the end of a contraction (ESV). Since stroke volume is the difference between how full the ventricle is before it contracts and how empty it is at the end of a contraction, sympathetic input increases stroke volume.

The respiratory membrane is found at the site of external respiration. What best describes the respiratory membrane? Correct! It exists between the walls of the alveoli and the walls of the pulmonary capillaries It lines the nasal cavity It lines the trachea It lines the intrapleural space

It exists between the walls of the alveoli and the walls of the pulmonary capillaries Right! The respiratory membrane is the site of gas exchange - the site of external respiration. It is a very thin barrier made of the walls of the alveoli (type I alveolar cells) and the endothelial cells of the pulmonary capillary. Because it is so thin, it easily allows the diffusion of gases between the alveoli and the capillary blood. The respiratory epithelium lines the nasal cavity, trachea and bronchioles - proximally it is PCCE and serves to cleanse, humidify and warm incoming air. The intrapleural space is between the visceral and parietal pleura; the pleura properly are created by a simple squamous epithelium and underlying connective tissue. Although anatomically similar to half of the respiratory membrane, the pleura produce a fluid that creates surface tension and lubricates movements of the lungs.

Which of the following best describes the air in the alveloi? It has a PO2 of 40 mmHg Correct! It has a PO2 of ~100 mmHg It has a PCO2 of ~100 mmHg It has a PCO2 of 45 mmHg

It has a PO2 of ~100 mmHg

Which of the following occur when ATP production increases at the tissues? Less oxygen is offloaded to the tissues Fewer H+ ions are buffered by hemoglobin in systemic capillaries Correct! More CO2 is produced in the RBCs at the pulmonary capillary More CO2 is transported by albumin Less bicarbonate ions (HCO3-) are made in the systemic capillaries

More CO2 is produced in the RBCs at the pulmonary capillary Right! When the tissues begin making more ATP they also make more CO2 (by aerobic metabolism). That CO2 diffuses into the blood and causes more O2 to be offloaded because high CO2 decreases hemoglobin's affinity for O2 and thus more O2 is released to the tissues. More H+ ions are made and the hemoglobin can buffer them because they have given up more O2 and now can bind more H+ to form HHb. At the tissues, more HCO3- is made when CO2 production increases. The confusing part is that the HCO3- and HHb travel in the blood up to the lungs and in the pulmonary capillary, the H+ comes off of the HHb (as oxygen binds to Hb) and binds to the HCO3-. When this happens, CO2 and H2O are formed. SO, CO2 is made in RBC in pulmonary capillaries because that CO2 can then diffuse into the alveoli and be removed from the body. Albumin does not transport CO2.

What happens if capillary colloid osmotic pressure is greater than capillary hydrostatic pressure? (Imagine interstitial hydrostatic pressure and interstitial osmotic pressure are both 0 mmHg.) More fluid would be pushed out of the capillary into the interstitial fluid than would be pulled in from the interstitial fluid into the capillary. Correct! More fluid would be pulled into the capillary from the interstitial fluid than would be pushed out from the capillary plasma to the interstitial fluid. No fluid would cross the capillary wall.

More fluid would be pulled into the capillary from the interstitial fluid than would be pushed out from the capillary plasma to the interstitial fluid.

As presented in the capillary shown in Model 3 (be sure to use your data table), is all the fluid that is pushed into the interstitial space from the arterial end reabsorbed at the venous end? If not, where does it go? Yes, it all goes back into the venous end of the capillary. Correct! No, the extra fluid is drained away by the lymph vessels. No, the extra fluid collects in the tissue.

No, the extra fluid is drained away by the lymph vessels.

For each of the following phases, use the drop down menu to indicate the relative pressures between the regions of the left side of the heart.

Passive filling of ventricles L atrium > L.ventricle < Aorta Active filling of ventricles L atrium > L.ventricle < Aorta Isovolumetric contraction of ventricles L atrium < L.ventricle < Aorta Ejection of ventricular blood into aorta/PT L atrium < L.ventricle > Aorta Isovolumetric relaxation of ventricles L atrium < L.ventricle < Aorta Atria and ventricles both relaxed, AV valves opened, SL valves closed L atrium > L.ventricle < Aorta

Which of the following will cause fluid to collect in the interstitial space (create tissue edema)? Correct! Permeability of the lymphatic capillaries decreases Increased production of albumin by the liver Permeability of the systemic capillaries decreases at the arterial end Blood pressure decreases at the arterial end

Permeability of the lymphatic capillaries decreases Right! If the lymphatics cannot drain away the fluid in the interstitial space, fluid accumulates - this condition is called edema. The more permeable the lymphatics, the more fluid it can drain. If the blood capillary becomes less permeable or blood pressure drops, less fluid leaves the systemic capillaries to create interstitial fluid. If blood albumin level increases, more fluid will be kept in the capillary (more pulled in to oppose capillary hydrostatic pressure) and less fluid will enter the interstitial space. Administration of proteins in IV fluid therapy is a way to increase blood volume and maintain that blood volume because the proteins act to suck fluid towards them so that less fluid can become interstitial fluid.

According to our worksheet 3, what creates the colloid osmotic pressure of the capillary? Blood pressure (hydrostatic pressure) Ions Correct! Plasma proteins

Plasma proteins

What is the correct path of a red blood cell as it moves through the healthy kidney? Correct! Renal artery - afferent arteriole - glomerulus - efferent arteriole - peritubular capillary - renal vein - inferior vena cava Renal artery - afferent arteriole - peritubular capillary - efferent arteriole - glomerulus - renal vein - inferior vena cava Renal artery - afferent arteriole - glomerulus - bowman's capsule - proximal convoluted tubule - peritubular capillary - renal vein - inferior vena cava Renal artery - efferent arteriole - glomerulus - afferent arteriole - peritubular capillary - renal vein - inferior vena cava

Renal artery - afferent arteriole - glomerulus - efferent arteriole - peritubular capillary - renal vein - inferior vena cava Yes! Blood cells are not filtered into the Bowman's capsule. They remain within the walls of the blood vessels and so this question really just asks about the flow of blood through the kidney. This answer would be the same if the question asked What is the correct order for a sodium ion that is not filtered at the glomerulus or secreted into the tubule? Please review blood flow through the kidney using your lecture notes so that you know what vessels you are expected to know.

For Brandon, O2 transfer across the ____ is reduced by his pneumonia. Correct! Respiratory membrane Respiratory epithelium Visceral pleural Parietal pleural

Respiratory membrane

How is secretion different from reabsorption in the kidney? Secretion is a passive process that occurs based largely on size; it occurs between the glomerulus and the Bowman's capsule. Reabsorption uses active processes that require ATP. Correct! Secretion and reabsorption both use membrane proteins for substance transport, but secretion moves substances from the blood into the filtrate and reabsorption moves substances from the filtrate into the blood. Secretion and reabsorption both use membrane proteins for substance transport, but reabsorption moves substances from the blood into the filtrate and secretion moves substances from the filtrate into the blood. Reabsorption is a passive process that occurs based largely on size; it occurs between the glomerulus and the Bowman's capsule. Secretion uses active processes that require ATP.

Secretion and reabsorption both use membrane proteins for substance transport, but secretion moves substances from the blood into the filtrate and reabsorption moves substances from the filtrate into the blood. Filtration creates filtrate - it is the process where the blood pushes plasma like filtrate out of the glomerulus into the Bowman's capsule (also called glomerular capsule). It is passive and requires no ATP. Filtration allows anything dissolved in the plasma to leave the blood, except proteins and large molecules like antibiotics. It does not allow blood cells to leave the blood vessel. Reabsorption uses active processes (either directly or indirectly) to remove filtered substances from the filtrate to the blood. Most of reabsorption will occur in the proximal convoluted tubule (PCT) using sodium ion transport proteins that require ATP. Other molecules will then be linked to the Na+ movement (glucose, amino acids, HCO3- ions etc) and water will follow. Secretion is reabsorption in reverse - it uses membrane proteins to move substances from the peritubular capillary through the tubule cells into the filtrate. It is very useful if the blood contains excess solutes or the molecule was too big to be filtered at the glomerulus into the original filtrate. It can occur in the PCT or the distal convoluted tubule (DCT).

Total cross-sectional area refers a group of vessels (i.e. all the systemic capillaries). If we were to cut into every systemic capillary and measure their cross-sectional areas then sum these together, we would get total cross-sectional area for the systemic capillaries. Using the figure above, which vessels have the largest total cross-sectional area? Systemic arteries Correct! Systemic capillaries Systemic veins

Systemic capillaries

Using the figure above, which vessels have the smallest diameter? Systemic arteries Correct! Systemic capillaries Systemic veins

Systemic capillaries

Using the above figure, which vessels have the lowest average blood pressure? Systemic arteries Systemic capillaries Correct! Systemic veins

Systemic veins

Where would you find hemoglobin that is relatively O2 poor in a healthy resting person? Systemic arteries & pulmonary veins Correct! Systemic veins & pulmonary arteries Systemic & pulmonary veins Systemic & pulmonary arteries

Systemic veins & pulmonary arteries Great! During rest, the tissues consume O2 to make ATP. Blood that exchanges respiratory gases with the air in the alveoli picks up oxygen to become fully loaded with O2 (hemoglobin saturated to maximum, effectively 100%). This O2 rich blood leaves the pulmonary capillaries and flows to the pulmonary veins, left atrium, left ventricle and then the systemic arteries. When systemic arterial blood arrives at the resting tissues, the blood releases some of the O2 for the tissue cells to use. The blood then leaving the tissues will have less O2 (depending on how much was released to the tissue cells) and so systemic venous blood is relatively O2 poor (at rest, it has 75% of the O2 that they systemic arterial blood had). This systemic venous blood moves into the right atrium, right ventricle and then the pulmonary arteries. Because gas exchange in/out of the blood only occurs in 2 places (the pulmonary capillaries or the systemic capillaries) the amount of O2 in the systemic venous blood is equal to the amount of O2 in the pulmonary arteries.

Where would you find hemoglobin that is about 65% saturated with O2 in a healthy resting person? Correct! Systemic veins & pulmonary arteries Systemic arteries & pulmonary veins Systemic & pulmonary veins Systemic & pulmonary arteries

Systemic veins & pulmonary arteries Great! During rest, tissue PO2 is 40 mmHg. Blood that loads oxygen in the pulmonary capillaries becomes fully saturated with O2 (hemoglobin saturated to maximum, effectively 100%, though often in the high 90's). When blood arrives at the resting tissues and equilibrates, the blood achieves a PO2 of 40 mmHg. At 40 mmHg, hemoglobin is only 65% saturated (as determined by the oxygen-hemoglobin dissociation curve). Therefore, systemic venous blood is 65% saturated with oxygen. O2 does not leave the blood except at capillaries and so as blood flows through the heart from the systemic veins to the pulmonary arteries, no further oxygen is lost. Acordingly, pulmonary arterial blood has a PO2 =40 mmHg and also contains hemoglobin that is 65% saturated with oxygen.

What happens in an otherwise normal individual if their liver cannot produce albumin? Correct! The blood would lose fluid to the tissues and the tissues would become swollen (edema) The blood would gain fluid from the tissues and the tissues would become dehydrated

The blood would lose fluid to the tissues and the tissues would become swollen (edema)

How are the left and right sides of the heart similar or different? Correct! The left ventricle consumes more oxygen than the right ventricle. The left atrium receives more blood than the right atrium during diastole (fills with more blood). The right ventricle generates the same amount of pressure as the left ventricle during systole. The right side of the heart has a higher cardiac output than the left side of the heart. The left side of the heart has a higher cardiac output than the right side of the heart.

The left ventricle consumes more oxygen than the right ventricle. The left ventricle has more muscle mass and therefore requires more blood to be delivered to it by the coronary circulation. The left side generates much greater pressures than the right side because it must pump to the entire systemic circuit which has a very large resistance. Therefore, the left side must generate more pressure to overcome the resistance and keep blood moving to the tissues. All of the other options are incorrect because they either state or imply that the amount of blood returning to or leaving the heart is unequal on both sides. This is of course incorrect because the left and right sides must move the same amount of blood per unit time (same cardiac output) to prevent blood backing up in a circuit. When the left and right sides are not matched, this is called congestive heart failure.

What would happen if intrapleural pressure became 0 mmHg when thoracic volume increased? Correct! The lungs would not expand Intrapulmonary pressure would become more negative The lungs would operate normally because this is the condition during rest

The lungs would not expand Right! Negative intrapleural pressure creates a suction between the lung and chest wall (thoracic body wall). The parietal pleura line the inside of the chest wall; the visceral pleura are the outermost layer of the lung. Between the two layers is some fluid that creates surface tension and a sucking pressure (negative pressure). This negative pressure keeps the lungs sucked against the chest wall. Because the chest wall has a greater volume than the lungs and a volume that cannot drop below the limits of the bony ribs, the lungs are always somewhat inflated (open). When the chest wall expands during inhalation, the intrapleural pressure becomes more negative (goes from -4 mmHg to -8 mmHg) thus pulling the lungs outward further (inflating the lung). If this pressure were to become 0 mmHg (meaning equal to atmospheric pressure), there would be no suck between the pleura and the lung would collapse due to its own elastic forces.

Where does most reabsorption of the filtrate occur (most by total volume of the filtrate)? Correct! The proximal convoluted tubule Loop of Henle Distal convoluted tubule Collecting duct

The proximal convoluted tubule Yes! Most of the filtrate is reabsorbed immediately in the proximal convoluted tubule. The remaining filtrate is reabsorbed along the Loop of Henle, DCT & collecting duct. The hormones ADH & aldosterone affect the amount of water and salt reabsorbed in the DCT & collecting duct. Even though most of the filtrate is reabsorbed by the time it reaches the DCT & collecting duct, the affect of ADH is significant enough to allow more water to be reclaimed and a very low volume, concentrated urine can be produced.

Which of the following is important to establishing the concentration gradient observed in interstitial fluid of the renal medulla? Correct! The variable permeability of the loop of Henle A very high GFR Angiotensin II Aldosterone

The variable permeability of the loop of Henle Right! The ascending thick limb of the loop of Henle contains salt pumps and is impermeable to water. The descending limb is permeable to water. When salt is pumped out on the ascending side, that salt moves into the interstitial space. This increases the saltiness in the fluid (interstitial fluid) around the descending limb and draws water out of the descending limb (the water leaves the filtrate to try to dilute the interstitial fluid). As water leaves the descending limb, the filtrate becomes saltier. Then this saltier filtrate passes through the hairpin turn of the loop and up into the ascending limb. In the ascending limb salt pumps remove even more salt out to interstitial fluid around the descending limb. The more times this happens, the more salty the interstitial fluid becomes (this is the countercurrent multiplier). Also, because more salt is pumped toward the bottom of the ascending limb, the interstitial fluid of the deeper medulla becomes saltier than the superficial medulla. Angiotensin II and aldosterone do not affect this process. A very high GFR would result in less time for salt pumping and would eliminate (or diminish) the medullary concentration gradient.

In Model 3, which net direction does the CO2 equation move when the RBC is in the systemic capillary? Correct! To the right (to produce H+ & HCO3-) To the left (to produce CO2 & H2O)

To the right (to produce H+ & HCO3-)

In normal, healthy individuals, the diaphragm moves superiorly during exhalation. Correct! True False

True

In terms of influence on blood volume, the actions of ANP are antagonistic to the actions of angiotensin II and aldosterone. Correct! True False

True

In the normal continuous capillary, fluid moves out at the arterial end because capillary hydrostatic pressure is greater than blood colloid osmotic pressure. Correct! True False

True

Think about the equation: HHb + O2 --> HbO2 + H+ when answering: The lower hemoglobin's affinity for oxygen, the more hemoglobin can prevent blood acidosis. Correct! True False

True Affinity here refers to hemoglobin's greediness for oxygen. When affinity is high, hemoglobin binds oxygen tightly and does not release it. When affinity is low, hemoglobin releases oxygen readily. High levels of CO2, H+ ions (low pH) and high temperature cause shape changes in hemoglobin molecules that decrease hemoglobin's affinity for oxygen. When hemoglobin releases an oxygen molecule, it provides a binding site on the hemoglobin for an H+. Free H+ cause pH to decline - creating acidosis - but H+ bound to a protein cannot affect pH (the binding protein buffers against pH changes). Hemoglobin does just this - it binds a H+ when oxygen affinity is low and acts to prevent acidosis of the body.

The lower hemoglobin's affinity for oxygen, the more hemoglobin can prevent blood acidosis. Correct! True False

True Right!! Affinity here refers to hemoglobin's greediness for oxygen. When affinity is high, hemoglobin binds oxygen tightly and does not release it. When affinity is low, hemoglobin releases oxygen readily. High levels of CO2, H+ ions (low pH) and high temperature cause shape changes in hemoglobin molecules that decrease hemoglobin's affinity for oxygen. When hemoglobin releases an oxygen molecule, it provides a binding site on the hemoglobin for an H+. Free H+ cause pH to decline - creating acidosis - but H+ bound to a protein cannot affect pH (the binding protein buffers against pH changes). Hemoglobin does just this - it binds a H+ when oxygen affinity is low and acts to prevent acidosis of the body.

In normal, healthy individuals, the diaphragm moves superiorly during exhalation. Correct! True False

True Yes! When the diaphragm contracts, it moves inferiorly, increasing the size of the thoracic cavity to allow air to flow into the lungs. During quiet exhalation, the diaphragm relaxes and passively moves superiorly to decrease the size of the thoracic cavity and force air out of the lungs.

Match the Following:

Vasodilation in response to decreased local blood pressure =Myogenic autoregulation Corrects a sudden drop in blood pressure within seconds =Sympathetic activation Maintains blood pressure by regulating blood volume =Kidney

When would inspiratory air volume be lowest? (This is just the amount of air inhaled.) Correct! When intrapulmonary pressure = -1 mmHg When intrapulmonary pressure = -2 mmHg When intrapulmonary pressure = -5 mmHg When intrapulmonary pressure = -7 mmHg

When intrapulmonary pressure = -1 mmHg

Which of the following statements about blood velocity is true? The velocity of blood is faster in the capillaries than in the arteries. Correct! When total cross-sectional area of a group of vessels is small, velocity is high. Blood velocity does not change between the different vessels.

When total cross-sectional area of a group of vessels is small, velocity is high. Right! Velocity is inversely proportional to cross sectional area. There are many capillaries in parallel that cumulatively have a large cross sectional area. Because flow through the system is equal in arteries, capillaries and veins, velocity is slow in those vessels with high cross sectional area and fast in vessels with small cross sectional area. Slow velocity serves capillaries well because it allows for exchange between the blood and the tissues.

Can stroke volume increase if EDV does not change? Correct! Yes No

Yes Right! EDV is end diastolic volume (it is how full the ventricle is before it contracts). ESV is end systolic volume - it is how full the ventricle is at the end of a ventricular contraction (not all blood is actually pumped out of the ventricle with each beat - there is always some residual volume). The amount that is ejected is called SV (stroke volume) and it is calculated by this formula: SV = EDV-ESV. So, stroke volume can increase by increasing EDV or decreasing ESV. ESV will go down if the heart squeezes harder and ejects more. The higher the stroke volume, the greater the cardiac output (for a given heart rate).

The longer you hold your breath, what happens? (select all that apply) Your systemic arterial blood pH increases Your systemic arterial blood contains more free oxygen Correct! Your systemic arterial blood becomes more acidic Correct! Your systemic arterial blood pH contains more free H+ ions

Your systemic arterial blood becomes more acidic Your systemic arterial blood pH contains more free H+ ions

For a healthy individual at rest, which statement is most likely true about hemoglobin's affinity for oxygen? affinity is highest in the systemic venous blood affinity is lowest in the systemic arterial blood Correct! affinity is lowest in the pulmonary arterial blood affinity is highest in the pulmonary arterial blood

affinity is lowest in the pulmonary arterial blood

In people with emphysema, which structures are destroyed causing a reduction in surface area? Correct! alveoli bronchioles larynx scalenes

alveoli

Which of the following conditions would result in a decrease in blood pressure for the same cardiac output? (select all that apply) increase in blood viscosity Correct! decrease in blood viscosity increase in vessel length Correct! decrease in vessel length Correct! increase in vessel diameter decrease in vessel diameter

decrease in blood viscosity decrease in vessel length increase in vessel diameter

How did the diastolic blood pressure respond to heavy activity? stayed the same as light activity Correct! decreased compared to light activity Increased compared to light activity

decreased compared to light activity

How did the diastolic blood pressure respond to light activity? stayed the same as resting in all cases increased from resting Correct! decreased or stayed the same from resting

decreased or stayed the same from resting

In Brandon, what happens when muscular effort for inhalation (inspiration) is increased? Correct! he generates more negative inhalatory intrapleural pressures he generates less negative inhalatory intrapleural pressures he generates normal inhalatory intrapleural pressures

he generates more negative inhalatory intrapleural pressures

In the pulmonary capillaries: oxygen combines with water to form bicarbonate ions and hydrogen ions the blood leaving the pulmonary capillaries is more acidic than the blood entering carbon dioxide must detach from hemoglobin to allow oxygen to bind Correct! hydrogen ions combine with bicarbonate ions to form carbon dioxide and water the lowest PO2 must be in red blood cell mitochondria

hydrogen ions combine with bicarbonate ions to form carbon dioxide and water Right! In the pulmonary capillaries oxygen loads into the blood and CO2 moves into the alveoli. CO2 is made in the systemic tissue mitochondria (there are no mitochondria in the RBCs) and transported away from tissue cells using the blood. Some CO2 dissolves in the plasma, some attaches to hemoglobin (NOT at the same binding site for oxygen) and the rest is converted to bicarbonate ions. The most conversion occurs inside RBCs where the enzyme carbonic anhydrase combines CO2 & water to create a hydrogen ion (H+) and bicarbonate ion (HCO3-). [Even though all the components of CO2 are found in bicarbonate ion, they are in the form of bicarbonate ion and not CO2.] The RBC then pushes bicarbonate out to the blood plasma and hemoglobin binds the H+. Some dissolved CO2 spontaneously combines with water to also make bicarbonate and H+ - acidifying the venous blood. The RBC then moves through the vascular tree up to the pulmonary capillaries. Once in the pulmonary capillaries, CO2 must move out of the blood into the alveoli for removal from the body. Bicarbonate ion cannot diffuse out of the blood into the alveolus, instead we need to "remake" CO2. To recreate CO2, bicarbonate ions combine with H+ and form CO2 and water in the RBC (also due to carbonic anhydrase). The CO2 then diffuses into the alveoli. The blood leaving the pulmonary capillary has less CO2 dissolved (because dissolved CO2 also moved into the alveoli) and therefore also has less free H+, making the pulmonary venous blood less acidic than the pulmonary arterial blood. O2 does not combine with water to make bicarbonate.

Which of the following will directly increase cardiac output? decreased SV with no change in HR increased ESV with no change in HR Correct! increased EDV with no change in HR decreased SA node firing rate with increased ESV

increased EDV with no change in HR Right! CO = HR x SV SV = EDV - ESV Increasing EDV leads to a higher SV because of the Frank-Starling law of the heart. The more blood that returns to the heart, the stronger the heart contraction to empty more blood. Any increase in ESV will decrease CO because of a lower SV. A decreased SA node firing rate is the same as slowing the heart rate, and a lower HR with the same or lower SV means a lower CO.

Using Model 3, why does increasing blood plasma protein concentration impact GFR the way it does? Correct! it increases glomerular colloid osmotic pressure, thus decreasing GFR it decreases glomerular hydrostatic pressure, thus decreasing GFR it increases Boman's capsule hydrostatic pressure, thus increasing GFR

it increases glomerular colloid osmotic pressure, thus decreasing GFR

During reabsorption, solutes and water move out of the renal tubule into the interstitial space. Most of these reabsorbed materials then ____. drain into the renal pelvis before returning to the general circulation. remain in the interstitial space increasing the volume of the kidney. move into the lymphatics by hydrostatic pressure gradients. Correct! move into the peritubular capillary by diffusion or osmotic pull.

move into the peritubular capillary by diffusion or osmotic pull. Right! During reabsorption, molecules first must leave the tubule lumen, then cross into the interstitial space. From there, reabsorbed substances move into the peritubular capillaries (or vasa recta). These molecules are pulled into the blood supply because the capillaries contain dissolved proteins that create an osmotic pull for the water, pulling in any dissolved substances as well. Some molecules enter the capillary because they move down their own diffusion gradients. The slow speed of the blood moving through the capillaries is very important here to allow for the entry of reabsorbed substances. While lymphatics are present in the kidney, most reabsorbed substances do not return to the circulation through the lymphatics. If they did, the renal lymphatics would be responsible for moving about 180 L/day! If the majority of the reabsorbed substances remained in the kidney, the kidney volume would become enormous, but also, the blood would not maintain proper water, solute and waste balance. Since the blood supplies fluid to tissues, the tissue fluid would then become unbalanced and tissue cells would not be able to perform their duties. Any fluid entering the renal pelvis is to be lost to the environment as urine. Reabsorbed substances would not be in the urine (unless they were later secreted after being reabsorbed, and even still, this is not most of the substances).

During reabsorption, solutes and water move out of the renal tubule into the interstitial space. Most of these reabsorbed materials then ____. Correct! move into the peritubular capillary. remain in the interstitial space increasing the volume of the kidney. move into the lymphatics. drain into the renal pelvis before returning to the general circulation.

move into the peritubular capillary. During reabsorption, molecules first must leave the tubule lumen, then cross into the interstitial space. From there, reabsorbed substances move into the peritubular capillaries (or vasa recta). These molecules are pulled into the blood supply because the capillaries contain dissolved proteins that create an osmotic pull for the water, pulling in any dissolved substances as well. Some molecules enter the capillary because they move down their own diffusion gradients. The slow speed of the blood moving through the capillaries is very important here to allow for the entry of reabsorbed substances. While lymphatics are present in the kidney, most reabsorbed substances do not return to the circulation through the lymphatics. If they did, the renal lymphatics would be responsible for moving about 180 L/day! If the majority of the reabsorbed substances remained in the kidney, the kidney volume would become enormous, but also, the blood would not maintain proper volume, or water, solute and waste balance. Since the blood supplies fluid to all tissues, the tissue fluids would then become unbalanced and tissue cells would not be able to perform their duties. Any fluid entering the renal pelvis is to be lost to the environment as urine. Reabsorbed substances would not be in the urine (unless they were later secreted after being reabsorbed, and even still, this is not most of the substances).

What regions of the respiratory tract are in the Anatomical Dead Space (select all that apply). parietal pleura Correct! nose alveoli mediastinum Correct! bronchiole Correct! pharynx Correct! bronchi Correct! trachea

nose bronchiole pharynx bronchi trachea

What is the name of the connective tissue layer that adheres to the ribcage? visceral pleura Correct! parietal pleura intercostal pleura diaphragm

parietal pleura

After sensing a drop in arterial blood pressure, baroreceptors send their sensory information to the medulla oblongata. The motor neurons trigger which of the following changes? (select all that apply) Correct! peripheral vasoconstriction Correct! increased heart rate Correct! increased contractility of the heart peripheral vasodilation

peripheral vasoconstriction increased heart rate increased contractility of the heart

Brandon had severe pneumonia (perhaps as well a chronic respiratory condition). In pneumonia, inflammation in the respiratory system causes increased porosity at the pulmonary capillaries as well as inflammation in the bronchioles, narrowing their diameter. In the bronchioles, airway constriction decreases lung compliance and increases the work of breathing. For Brandon, when his pulmonary capillaries become overly porous, albumin leaks into the extracellular fluid (ECF). What does this cause and why? pulmonary edema due to low capillary hydrostatic pressure alveolar cell dehydration due to high capillary hydrostatic pressure alveolar cell dehydration due to high blood colloid osmotic pressure Correct! pulmonary edema due to low blood colloid osmotic pressure

pulmonary edema due to low blood colloid osmotic pressure

Using this image (Model 3 from worksheet), what factor decreases GFR the most? Correct! severe blood loss ANP mean arterial pressure blood protein composition

severe blood loss

Which of the following will be the response of the nephron to increase filtrate formation in response to too little filtrate flowing past the distal convoluted tubule? Correct! the afferent arteriole will dilate the afferent arteriole will constrict the efferent arteriole dilates less renin is released

the afferent arteriole will dilate

For Brandon, his care team administered inhaled air with an O2 concentration of 40%. This air is also delivered at a high flow rate, but a total pressure of ~760mmHg. What is the advantage of this in Brandon? to increase the total intrapleural pressure to increase the rate of airflow through the bronchioles to increase the total intrapulmonary pressure Correct! to increase the rate of oxygen diffusion into the pulmonary capillary

to increase the rate of oxygen diffusion into the pulmonary capillary

Under normal resting conditions or light exercise, the primary factor altering cardiac output is: Correct! venous return sympathetic stimulation of the heart parasympathetic stimulation of the heart hormonal stimulation of the heart

venous return Venous return is the volume of blood returning to the heart from systemic veins. It is the primary mechanism for changing cardiac output as explained by the Frank-Starling law of the heart. The more blood that flows into the heart, the more blood that will be pumped out thus altering cardiac output. Changes in hormones or neural stimuli do alter cardiac output, but the primary mechanism that acts to alter cardiac output to match tissue demands at rest and during routine activity is venous return. Parasympathetic activation keeps cardiac output low at rest, but it does not affect changes to match needs during shifts in venous return.

For Brandon, before he received treatment, he had systemic arterial PCO2=67 mmHg, PO2=69 mmHg, and pH=7.36. How saturated is his systemic arterial hemoglobin (in this initial state)? >95% ~90% Correct! ~80% ~69%

~80%