MPP 3202 Block 3 Exam Review

Blood consists of

water

cells and platelets

ions and organic molecules

all of the above

d

Plasma oncotic pressure is dependent on its concentration of

albumin

epinephrine

acetylcholine

immunoglobulin

a

At the moment of peak ventricular pressure,

AV valves are open and semilunar valves are closed

Both AV and semilunar valves are closed

AV valves are closed and semilunar valves are open

Blood is flowing from the vena cava into the right ventricle

c

Electrical signals starting in the sinoatrial (SA) node pass through the atrial myocardium, then

Pass directly into the ventricles

Are routed through the conduction system that passes down the septum to Purkinje fibers at the apex of the ventricles

Pass directly to the Purkinje fibers, and end in the atrioventricular (AV) node

Trigger firing of baroreceptors in the aortic arch

b

How does norepinephrine increase cardiac output?

Solely via a positive chronotropic effect

Solely via a positive inotropic effect

It has a positive chronotropic effect and negative inotropic effect

It has both positive chronotropic and inotropic effects

d

What is the Frank-Starling law of the heart?

As capillary hydrostatic pressure increases, fluid filtration from the capillary increases

As ventricular filling increases, stroke volume increases

As end diastolic volume decreases, stroke volume increases

As cardiac output increases, blood pressure decreases

b

Cardiac output (CO)

Is the product of stroke volume and heart rate

Is the product of end diastolic volume and oncotic pressure

Can be increased by increased venous return and epinephrine

A & C

d

At the same instant in which left ventricular diastolic pressure is about 0, aortic diastolic pressure is about 80 mm Hg. Why?

Aortic afterload is high

Elastic recoil in the aorta maintains a higher pressure in that vessel during diastole

The aorta is a rigid tube, so pressures tend to stay higher

The aorta can hold more blood than other vessels, so its pressure is always high

b

Autonomic control of total peripheral resistance (TPR) is mainly centered on which vessel type?

Arterioles

Large arteries

Capillaries

Post-capillary venules

a

What structural feature of capillaries throughout the body facilitates exchange of fluid and solutes between blood and tissues?

The sodium/potassium ATPase pumps in their endothelial lining.

ADH-stimulated insertion of aquaporin channels into their endothelial lining

Their walls are very thin, so that diffusion distance is minimized

Their layer of vascular smooth muscle, which help squeeze blood out into the interstitium

c

The net filtration pressure (NFP) in renal glomerular capillaries is +15 mm Hg, while the NFP in renal peritubular capillaries is -29 mm Hg. Which processes are favored in each of these respective capillary beds?

Absorption in both

Filtration and absorption, respectively

Filtration in both

Absorption and filtration , respectively

b

In a given vascular bed under normal conditions, resistance to blood flow increases if

Arteriolar diameter increases

Upstream pressure decreases

Arteriolar diameter decreases

Capillary viscosity decreases

c

The major determinant of total peripheral resistance at rest (e.g. just sitting around) is

Metabolic hyperemia

Maximal dilation of arterioles

Sympathetic tone

Cardiac output

c

Moment-to-moment regulation of blood pressure is via

Rapid adjustments of sodium and water retention vs excretion by the kidneys

Arterial baroreceptor-triggered autonomic signals which rapidly adjust cardiac output and total peripheral resistance

Active opening and closing of valves in the venous system

Parasympathetic signals which decrease heart rate

b

Why might a defect in left ventricular function result in difficulty breathing?

Increased ventricular pressure causes the heart to swell up, getting in the way of the lungs

Decreased pumping of blood into the lungs by a failing left ventricle would decrease the blood flow needed to pick up sufficient oxygen

The decreased cardiac output would cause the kidneys to excrete more water

Increased hydrostatic pressure in the pulmonary vascular bed due to backup of blood behind the left heart would cause fluid leakage from pulmonary capillaries, leading to pulmonary edema

d

The extracellular fluid (ECF) compartment is comprised of

The vascular and interstitial spaces

Bowman's space and the afferent arteriole

The effective circulating volume and end diastolic volume

The intracellular fluid (ICF) compartment and the ECF compartment

a

Differences in osmotic pressure determine the distribution of water between _________ compartments, and are a function of _____________.

The ECF and the plasma, ECF sodium concentration

The ECF and ICF, ECF sodium concentration

The plasma and interstitial space, plasma sodium concentration

The ECF and ICF, ICF protein concentration

b

In regard to body fluid homeostasis, what is the major role of the lymphatic system?

Return of filtered fluid to the vascular system

Removal of excess fluid from the vascular system

It's an overflow system for when too much water is ingested

It reabsorbs water and sodium from the medullary collecting duct in response to ADH

a

Plasma oncotic pressure

Tends to drive fluid from capillaries into the interstitial space

Drives fluid out of lymph vessels into the interstitial space

Tends to hold fluid within the vascular space

Prevents water leaking out of the ICF

c

Despite large amounts of glucose being filtered out of plasma in glomerular capillaries, one normally does not see glucose in the urine. Why?

Glucose is reabsorbed by the bladder

Glucose is completely reabsorbed in the proximal tubules

Glucose is also secreted into the distal tubules

Less glucose is filtered out of the blood than stays in

b

About 90% of renal blood flow goes to the cortex. This makes sense in light of which of the following?

The greatest quantities of water, sodium, and other needed molecules are reabsorbed in the proximal tubules, which are located in the cortex

Filtration of blood is in the glomerulus, which resides in the cortex

Most water and sodium are reabsorbed in the distal tubule, which is in the cortex

A & B

d

Ingestion of a large amount of salt (Na+) results in

Increased ECF osmolality

ADH release

Reabsorption of water

All of the above

d

ADH is produced and released by neurosecretory cells. The cell bodies of these cells are located in

The hypothalamus

The posterior pituitary

The adrenal medulla

The renal nephron

a

Granular cells in the wall of the afferent arteriole release _________ in response to a drop in glomerular filtration rate. This is the first step in a hormonal effector mechanism whose effect is to _______________.

Angiotensin II, increase sodium excretion

Renin, reabsorb sodium

Aldosterone, reabsorb potassium

ADH, switch off hypothalamic osmoreceptors

b

The kidney senses a drop in ECF volume

As a drop in blood pressure

As an increased glomerular filtration rate

Directly via volume sensors in the renal interstitial space

As an increase in plasma oncotic pressure

a

In a patient with liver disease, which of the following plasma solutes might be decreased, and what would be an outward sign of this?

Atrial natriuretic peptide, decreased blood pressure

Albumin, generalized edema

Aldosterone, increased blood pressure

Sodium, increased blood pressure

b

Excessive loss of ECF volume might not be expected to directly influence ICF volume unless

The lost fluid had a lower sodium concentration, such that the loss was mostly water, leaving behind the salt

The lost fluid had a very high sodium concentration, so that it would draw more water out of cells

All the fluid was being lost via respiration

The lost fluid had a high protein concentration

a

What is pressure diuresis?

Retention of water by the kidney in response to increased blood pressure

Excretion of glucose in response to increased blood pressure

Increased urinary excretion of water due to increased total peripheral resistance

Increased urinary excretion of water in response to increased pressure seen by the kidneys

d

The renal equilibrium point

Is where renal output of sodium and water matches mean arterial pressure

Is determined by the position of the renal output curve with respect to mean arterial pressure and by the level of sodium intake

Is the point where renal output of sodium and water match their intake

B & C

d

Why does eating salt produce an increase in blood pressure?

Salt increases aldosterone secretion

Correction of the increase in plasma osmolality by renal water retention and thirst-induced drinking increases plasma volume

Sodium has a direct inotropic effect on the heart

Sodium directly stimulates the renin-angiotensin-aldosterone system

b

If the kidneys are functioning normally, how do they respond to the high blood pressure produced in response to ingestion of a large quantity of salt?a They increase production of reninb They stop releasing aldosteronec The higher pressure drives increased renal output of salt and water in order to lower pressure back down to the normal equilibrium pointd They increase their production of angiotensin II

c

Acid-base homeostasis in the ECF

Requires chemical buffers, and normal respiratory and renal function

Is totally dependent on extracellular buffers

Depends on the ratio of ICF bicarbonate to PCO2

Is impossible with high blood pressure

a

The most important chemical buffer system in the ECF is that of

Intracellular protein and phosphate (HPO4-)

Plasma levels of ammonia (NH3)

Bicarbonate (HCO3-)

Hydrochloric acid (HCl)

c

The value of the bicarbonate buffer system in the control of acid being generated during metabolism is in

The ability of the lungs to blow off CO2

Bicarbonate's ability to instantly remove free hydrogen ions (H+) from solution, thus preventing changes in pH

The ability of the kidneys to maintain ECF bicarbonate (HCO3-) levels

All of the above

d

If plasma PCO2 increases

Peripheral and central chemoreceptors trigger decreased respiratory rate

Chemoreceptors trigger increases in respiration rate

Chemoreceptors trigger increases in renal bicarbonate excretion

The kidneys increase renal excretion of CO2

b

The limiting factor in the bicarbonate buffer system is

The ability to rapidly adjust respiration rate

PCO2

The supply of bicarbonate (HCO3-)

There is no limiting factor

c

What is the nature of the initial defect in metabolic acidosis? What is the initial compensatory response?

Inability to breathe out CO2, decreased breathing out of bicarbonate

A deficit in ECF bicarbonate, increased breathing out of CO2

Inability to excrete bicarbonate, decreased breathing out of CO2

Inability to breathe out CO2, increased breathing out of CO2

b

What is the mechanism whereby filtered bicarbonate is reabsorbed in the proximal tubules of the nephron?

Direct absorption by simple diffusion

Direct absorption by secondary active transport

Indirect absorption by combining with secreted ammonia

The above reaction (figure above) runs to the right in the lumen, CO2 + H2O are absorbed, then inside the cell the same reaction runs in reverse. Regenerated H+ is secreted back into the lumen and the HCO3- is returned to the blood

d

If there is more H+ in the renal tubular lumen then there is HCO3- to buffer it, the pH in the lumen may fall so low that H+ secretion is inhibited (renal tubular acidosis). Under normal conditions, what prevents excessive tubular free H+ from building up?

Additional tubular buffering in the form of phosphate and ammonia

Protein in the lumen can act as a buffer

Increased filtration of bicarbonate to make up the deficit

Vomiting to get rid of extra acid

a

The purpose of having values min the cardiovascular system is to

provide sounds so that heart health can be monitored

ensure blood from flowing too quickly

prevent blood from flowing too quickly

regulate blood pressure

provide the force for circulation

ensure that blood flows in one direction

The driving force for blood flow is a(n) ________ gradient.

osmotic

volume

pressure

gravity

electrochemical

pressure

Each of the following changes will result in increased blood flow to a tissue except one. Identify the exception.

increased blood volume

decreased vessel diameter

increased blood pressure

decreased peripheral resistance

relaxation of precapillary sphincters

decreased vessel diameter

Which of the following will increase flow in a vessel the most?

decrease length by 1 unit

increase radius by 1 unit

decrease viscosity by 1 unit

decrease the pressure gradient by 1 unit

all have the same effect on flow

increase radius by 1 unit

The rapid depolarization phase of the action potentials of myocardial contractile cells is due to which ion(s)?

Ca2+ only

K+ only

Na+ only

Both Ca2+ and K+

Both Na+ and K

Na+ only

The flattening of the action potentials of myocardial contractile cells, called the plateau phase, is due to a combination of ________ K+ permeability and ________ Ca2+ permeability.

increasing, increasing

decreasing, decreasing

increasing, decreasing

decreasing, increasing

no change in, decreasing

decreasing, increasing

The action potentials of myocardial auto rhythmic cells are due to a combination of increasing Na2+ ___ and decreasing K+ ____.

influx, efflux

efflux, influx

influx, influx

efflux, efflux

influx, efflux

The importance of the plateau of the action potential of myocardial cells is in

preventing overstretching of the cells

enhancing the efficiency of oxygen use by the cells

preventing tetanus

preventing fibrillation

regulating Na+ availability to the cells

preventing tetanus

The AV node is important because it

directs electrical impulses from the ventricles to the atria

delays the transmission of the electrical impulses to the ventricles in order for the atria to finish contracting

serves as the pacemaker in a normal heart

electrically opens the AV valves

none of these answers are correct

delays the transmission of the electrical impulses in order for the atria to finish contracting

The QRS complex of an ECG corresponds to

the depolarization of the atria

the progressive wave of ventricular depolarization

the repolarization of the ventricles

atrial repolarization

none of the answers are correct

the progressive wave of ventricular depolarization

Which of the following events result in the first heart sound?

the AV valves open

the AV valves close

the semilunar valves close

the semilunar valves open

the atria contract

the AV valves close

What is the primary function of the cardiovascular system?

transport; transports oxygen from lungs to all cells, nutrients and water from the intestinal tract to all cells, waste from some cells to the liver, immune cells from the blood to any cell in need, hormones from the endocrine glands to target cells, and nutrients from adipose tissue and liver to all cells

Circulation is used to deliver all things

Blood flow process

Arteries- carry blood away from the heart

Veins- carry blood back to the heart

Small veins->large veins->venae cavea->right atrium->right ventricle->pulmonary artery->lungs->pulmonary vein->left atrium->left ventricle->aorta->arteries->capillaries

systole

The time when the heart is contracting- 1/3 of the time- this is the only time that the heart is pumping out bloodDuring systole- the partial contraction forces a small amount of additional blood into ventricles

diastole

the time when the heart fills with blood- relaxation

ventricles fill passively

resistance and blood flow

If resistance increases, flow decreases

If resistance decreases, flow increases

Resistance increases as length and viscosity increase, resistance decreases as the radius increases

If you double the radius- flow increases by 16x

Vasoconstriction

decrease in blood vessel diameter and decrease in blood flow

Vasodilation

increase in diameter of a blood vessel and increase in blood flow

flow=

pressure gradient/vascular resistance

Velocity

the narrower the vessel, the faster the velocity of flow

as cross-sectional area increases, the velocity of the flow decreases

Cardiac output

the amount of blood being pumped out of the heart at any given moment

What is the function of the valves in our heart?

ensure one way flow

Atrioventricular valves

between atria and ventricles (right-tricuspid, left-bicuspid)

semilunar valves

ex: pulmonary valve, aortic valve

types of cells in the heart

contractile cells, auto rhythmic cells

contractile cells

organized into sarcomeres

autorhythmic cells

pacemaker, signal for contraction, less of these cells and no sarcomeres

intercalated disc function

Attach the myocardial muscle and if one cell is activated all the cells will be activated because of the intercalated discs

cardiac muscle contraction

Can be graded- if you increase the number of cross bridges you will increase the force of contraction, stretching of the heart increases cross bridges which results in a stronger contraction

refractory period

cell cannot respond to other stimuli during the refractory period which prevents cardiac muscle tetanus

electrical conduction

AV node (atrioventricular) helps route the direction of electrical signals so the heart contracts from apex to base (top to bottom)

ECG reading

P wave- partial depolarization

P-R segment- conduction through the atrioventricular node

QRS complex- progressive wave of ventricular depolarization

T wave- repolarization of ventricles

Cardiac Cycle

1. during late diastole both sets of chambers are relaxed and ventricles fill passively

2. during artial systole the arterial contraction forces a small amount of additional blood into the ventricles

3. during isometric ventricular contraction- AV valves close but semilunar valves are not opened

4. during ventricle ejection the ventricle pressure is rising and the semilunar valves open and blood is ejected

5. during isovolumic ventricular relaxation the pressure in ventricle falls and the blood flows back into cusps of semilunar valves and they close

first heart sound

The closure of AV valves causes a vibration and accounts for the first heart sound

second heart sound

the closure of the semilunar valves causes a vibration which creates the second heart sound

Auscultation

listening to the heart through chest wall with a stethoscope

blood supply

The heart and brain need a constant supply of blood- skeletal muscle receives 21% of blood supply

Function of vessel types

Capillaries- exchange between blood and cells

Post Capillary Venules- exchange and support leukocytes

Systemic Veins- expandable volume reservoir

Arterioles- Alter diameter at the site of variable resistance

Systemic Arteries- Pressure reservoir that maintains blood flow and provides a mean of transportation

pre-capillary sphincters

Function is to close off capillaries in response to local signals, when relaxed blood flows freely through all capillaries in bed, if pre capillary sphincters constrict, blood flow bypasses capillaries and flows through met arterioles

characteristics of capillaries that facilitate exchange between blood and tissues

absence of a vascular smooth muscle, large surface area, and elastic tissue reinforcement

capillary density

related to the metabolic activity of cells in the tissue

brain and heart have a high capillary density

skeletal muscle does when working out

fenestrated capillaries

have large pores (fenestra) that let molecules pass very readily - these are found in the GI tract and kidney

continous capillaries

found in heart, brain and skeletal muscle and skin, very thin in order to maximize exchange (lipid soluble)

Discontinued capillaries

Found in liver and spleen, separated by huge gaps, protein molecules pass readily which is important to liver function

Also called sinusoids

bulk flow

mass movement of fluid as the result of hydrostatic or osmotic pressure gradients

water carrying substances w it

absorption

fluid movement into the capillaries

transcytosis

vesicular transport - brings proteins and macromolecules across the endothelium. an exchange between plasma and interstitial fluid - occurs by paracellular pathways

filtration

fluid movement out of capillaries

functions of lymphatic system

1. returning fluid and proteins filtered out of the capillaries to the circulatory system.

2. picking up fat absorbed at the small intestine and transferring it to the circulatory system.

3. serving as a filter to help capture and destroy foreign pathogens.

causes of edema

1. inadequate drainage of lymph- blocked in some way with no where to go2. Filtration is far greater than absorption- malnutrition, vasodilation

How do valves ensure one way flow?

By forcing blood towards the heart when compressed by skeletal muscle

factors that influence the mean arterial pressure

1. blood volume- determined by fluid loss or intake

2. effectiveness as heart as a pump- determined by heart rate and stroke volume

3. Resistance of the system to blood flow- determined by the diameter of arterioles

4. Relative distribution of blood between artenal and venous blood vessels- determined by the diameter of veins

compensation for increased blood flow

As blood volume increases, blood pressure increases

2 compensatory mechanisms

1. Fast response is compensated by the cardiovascular system by vasodilation and decrease in cardiac output

2. Slow response is compensated by the kidneys, by the excretion of fluid in urine which brings down blood volume

arteriolar resistance

influenced by both local and systemic controls mechanisms

local

sympathetic

hormones

myogenic tone

Always partially contracted, even without nerve influence

adenosine

breakdown product of ATP-which can leak out of cells and cause vasodilation

sympathetic tone

keeps most blood vessels partially constricted and maintains blood pressure

blood flow and tissue metabolism

If tissue metabolism increases- there must be an increase in the release of metabolic vasodilators into Extracellular fluid, arterioles dilate and a decrease in resistance causes an increase in blood flow

Baroreceptors

Detects pressure changes. Monitors BP and Blood flow by sensing pressure changes within vessels and organs.

Blood composition

Plasma-> made up of water, ions, organic molecules, trace elements, vitamins, and gases

Cells-> Red blood cells (also called erythrocytes), white blood cells (also called leukocytes, these are immune cells) and platelets

function of plasma proteins

albumin

globulin

fibrinogen

transferrin

Albumin- colloid osmotic pressure, carrier for various substances

Globulin- clotting factors, enzymes, antibodies, carrier for various substances

Fibrogen- forms fibrin threads, essential to blood clotting

Transferrin- Iron transport