EXAM #3 Essay Q's Flashcards

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1
Q

Baroreceptor reflex: Describe the baroreceptor reflex that occurs as an immediate response to an increase in blood pressure.

Explain how this reflex allows for a short term decrease in blood pressure (cardiac center and vasomotor center response?).

Explain how a physician can use this knowledge to decease the heart rate of a patient with tachycardia.

Is this reflex effective for long-term regulation of blood pressure? Why or why not?

A

BP ↑ = ↑ stretch
↑ baroreceptor stimulation
CV center response ….. ↓ BP

↓ cardioaccleratory (↓ sympath)

↑ cardioinhibitory (↑ parasymp):

↓ vasomotor: causes peripheral vasodilation, ↓ R, sends to venous reserve

doctor can do internal carotid massage

baroreceptors become stimulated, know are stretched, help drop heart rate

tachycardia = abnormally fast heart beat

not effective long-term

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2
Q

Response to hemorrhage: Describe in detail how your body would respond to hemorrhage in effort to maintain blood volume and pressure

Consider short-term and long-term goals

How your body tries to achieve these goals

A

Short term elevation of blood pressure ….up to ~20% loss total blood volume

decreased CHP / increased BCOP recalls fluids from interstitial spaces

Long term: days to restore blood volume

erythropoietin stimulates RBC production

negative feedback when BV and BP return to normal

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3
Q

Explain in detail how the various components of red blood cells are recycled or disposed of and how each component arrives at its final destination

A

don’t divide, no nucleus

macrophages in spleen (graveyard) and liver

phagocytes recycle in red bone marrow

becomes globins protein and iron

becomes heme to later become bilirubin and biliverdin

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4
Q

Describe excitation through the conduction system of the heart and why it is advantageous to have a brief delay at the AV node

A

SA node generates impulse

internodal pathways to AV node (delayed)

to AV bundle splitting into left and right bundles

left and right bundles to Purkinje cells

benefit: atria finished contraction and forcing blood into ventricles before ventricles contract

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5
Q

why is the SA node the pacemaker

A

SA node (pacemaker): Fastest depolarization of all conduction system

SA rhythm determines HR

SA node rate: ~100 BPM

BUT: Normal HR slower: 75 BPM

WHY?: under continuous parasympathetic stimulation: vagal tone

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6
Q

cardiac cycle

A

look at chart

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7
Q

arteries vs veins

A

look at table

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8
Q

describe the overall blood pressure in the venous system. How is venous return facilitated despite the low blood pressure in circulation

A

low blood pressure

move blood back to heart against gravity

valves prevent backflow, and aids venous return

respiratory pump and muscular pump aid in venous return

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9
Q

net filtration pressure: be able to define…

capillary hydrostatic pressure CHP

blood colloid osmotic pressure BCOP

filtration

reabsorption

How would hemorrhaging or dehydration affect NFP

A

CHP = blood pushing against vessel walls

BCOP = draws water back into blood via osmosis

filtration = forces fluid out of blood into interstitial tissue

reabsorption = water pulled into blood

decreased CHP / increased BCOP recalls fluids from interstitial spaces

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10
Q

describe autoregulation

neuroregulation

endocrine regulation

A

autoreg = local at tissue level, immediate

neuro-regulation = sympathetic, parasympathetic
(autonomic reflex )

Endocrine regulation = hormones

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11
Q

what is preload, contractility, and afterload

A

preload is how much cardiac muscles are stretched before contacting

contractility is force of contraction

afterload is pressure to be overcome to force blood out of ventricles

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