ap 2 lecture: exam 1

step 1 of the cardiac cycle

atrial systole begins

step 2 of the cardiac cycle

atrial systole ends, atrial diastole begins

step 3 of the cardiac cycle

ventricular systole: first phases

step 4 of the cardiac cycle

ventricularsystole

step 5 of the cardiac cycle

ventricular diastole: early phases

step 6 of the cardiac cycle

ventricular diastole: late

what happens during atrial systole of the cardiac cycle

atrial contraction forces a small amount of additional blood into the relaxed ventricles

what happens during the first phases of ventricular systole of the cardiac cycle

ventricular contraction pushes AV valves closed but doesn’t create enough pressure to open SL valves

what happens during late ventricular systole of the cardiac cycle

as ventricular pressure rises and exceeds pressure in the arteries, the SL valves open and blood is ejected

what happens during early ventricular diastole of the cardiac cycle

as ventricles relax, pressure in ventricles drops; blood flows back against cusps of semilunar valves and forces them closed. blood flows into the relaxed atria

what happens during late ventricular diastole of the cardiac cycle

all chambers are relaxed and ventricles fill passively

continuous capillaries

capillary whose endothelial cells are tightly joined

fenestrated capillaries

capillary with large pores in the endothelium

sinusoids

irregular tubular space for the passage of blood, taking the place of capillaries and venules in the liver, spleen, and bone marrow

tunica externa

outermost layer, loose CT

tunica media

middle, thickest, smooth muscle

tunica interna

smooth inner layer, repels blood cells and platelets, simple squamous endothelium

skeletal muscle circulatory route

arterioles constrict at rest; arterioles dilate during exercise; muscular contraction impedes flow

lungs circulatory route

low pulmonary blood pressure, unique response to hypoxia

what is the only hormone that decreases BP

ANP

step 0 of contractile action potential

Na+ channels open (depolarization

step 1 of contractile action potential

Na+ channels close (initial repolarization)

step 2 of contractile action potential

Ca2+ channels open; fast K+ channels close (plateau)

step 3 of contractile action potential

Ca2+ channels close; slow K+ channels open (rapid repolarization)

step 4 of contractile action potential

resting potential

p wave

atrial depolarization

q wave

depolarization of ventricular septum

r wave

ventricular depolarization

s wave

final ventricular depolarization

t wave

ventricular repolarization

hyperemia

when blood flow adjusts to support different tissues throughout your body

what does CVCC stand for

cardiovascular control center

where is the CVCC

medulla oblongata

what does the CVCC do

help regulate HR and SV; specific neurons regulate blood vessel diameter

baroreflex

the primary reflex pathway for homeostatic control of blood pressure

baroreceptor

stretch-sensitive mechanoreceptors that respond to changes in pressure

proprioreceptors

sensory receptor who receives stimuli from within the body

angiotensinogen

prohormoned produced by liver

angiotensin I

ACE inhibitors block this enzyme lowering BP

angiotensin II

very potent vasoconstrictor

aldosterone

vasoconstriction, increases blood volume and pressure; promotes Na+, produced in adrenal cortex

ANP

generalized vasodilation

ADH

vasoconstriction

epinephrine

vasodilation

norephinephrine

vasoconstriction

intrinsic pathway in coagulation

activation occurs

extrinsic pathway

damaged tissues leak factor III into bloodstream

platelet plug step: adhesion

platelets stick to exposed collagen underlying damaged endothelial cells in vessel wall

platelet plug step: reaction

platelets activated by adhesion; extend projections to make contact with each other; release chemicals activating other platelets (ADP and PAF)

platelet plug step: aggregation

activated platelets stick together and activate new platelets to form a platelet plug; plug reinforced by fibrin threads formed during clotting process

platelet plug step 1

exposed collagen binds and activates platelets

platelet plug step 2

release of platelet factors

platelet plug step 3

factors attract more platelets

platelet plug step 4

platelets aggregate into platelet plug

coagulation

where fluid blood forms a gelatinous clot

plasma proteins: albumins

most abundant plasma protein; contributes to viscosity; influences blood pressure, flow and fluid balance

viscosity

thickness or resistance to flow of a solution

plasma protein: globulins

antibodies; provide immune system defenses; alpha, beta, gamma

plasma proteins: fibrinogen

precursor of fibrin threads that helps form blood clots

another word for red blood cells

erythrocytes

another word for white blood cells

leukocytes

hematocrit

percentage of blood occupied by cells

neutrophils (granulocyte)

varied nuclear shapes; nuclei have 2-5 lobes; fine and pale, 60-70% of WBCs

eosinophils (granulocyte)

nucleus with 2-3 lobes; large, uniform sized; 2-4% WBCs

basophils (granulocyte)

large, smaller, less than 1% of WBCs

lymphocyte (agranulocyte)

dark; sky blue color; small and large cells; 25-33% WBCs

monocyte (agranulocyte)

nucleus is oval; largest WBC; cytoplasm is blue gray; 3-8% of WBCs; travels through the blood to tissues in the body where it becomes a macrophage or a dendritic cell

when ventricles relax, do AV valves open or close

AV valves open

when ventricles contract, AV valves open or close

AV valves close

SA node

pacemaker, initiates heartbeat

AV node

electrical gateway to ventricles

AV bundle of his

pathway for signals from AV node

bundle branches

divisions of AV bundle that enter interventricular septum and descent to apex

purkinje fibers

upward from apex spread throughout ventricualr myocardium

ectopic focus

a region of spontaneous firing other than the SA node

sinus rhythm

the normal heartbeat triggered by the SA node

step 0 of autorhythmic action potential

If channels open

step 1 of autorhythmic action potential

some Ca2+ channels open, If channels close

step 2 of autorhythmic action potential

lots of Ca2+ channels open

step 3 of autorhythmic action potential

Ca2+ channels close, K+ channels open

step 4 of autorhythmic action potential

K+ channels close

step 1 of autorhythmic

SA node activity and atrial activation begin

step 2 of autorhythmic

stimulus spreads accross the atrial surfaces and reaches the AV node

step 3 of autorhythmic

there is a 100-msec delay at the AV node, atrial contraction begins

step 4 of autorhythmic

impulse travels along the interventricular septum within the AV bundle and the bundle branches to the purkinje fibers and via the moderator band to the papillary muscles of the right ventricle

step 5 of autorhythmic

impulse is distributed by purkinje fibers and relayed throughout the ventricular myocardium; atrial contraction is completed and ventricular contraction begins

step 1 of myocardium electrical behavior

rapid depolarization; Na+ entry; closure of voltage-gated sodium channels

step 2 of myocardium electrical behavior

plateau; Ca2+ entry; closure of slow calcium channels

step 3 of myocardium electrical behavior

repolarization; K+ loss; closure of slow potassium channels

electrical activity of myocardium step 1

atrial depolarization begins

electrical activity of myocardium step 2

atrial depolarization complete (atria contracted)

electrical activity of myocardium step 3

ventricles begin to depolarize at apex; atria repolarize (atria relaxed)

electrical activity of myocardium step 4

ventricular depolarization complete (ventricles contracted)

electrical activity of myocardium step 5

ventricles begin to repolarize at apex

electrical activity of myocardium step 6

ventricles repolarization complete (ventricles relaxed)

EDV

volume in ventricle at end of relaxation (130)

ESV

volume in ventricle at end of contraction (60)

SV

volume ejected per beat from each ventricle (70)

what causes increased stroke volume

increased preload, increased contractility, decreased afterload

the more blood the heart pumps and the narrower the arteries are, the higher or lower the blood pressure

higher