Unit 1 A&P 2

atrial reflex

atrial reflex

an autonomic reflex initiated by increased venous return and increased atrial filling

auricle

small, wrinkled, protruding appendages

cardiac output

amount of blood pumped out by each ventricle in 1 minute

cardiac reserve

difference between resting and maximal cardiac output

contractility

the contractile strength achieved at a given muscle length

diastole

periods of relaxation

end diastolic volume (EDV)

the amount of blood that collects in a ventricle during diastole

end systolic volume (ESV)

the volume of blood remaining in a ventricle after it has contracted

endocardium

endothelium membrane that lines the interior of the heart; white sheet of endothelium resting on connective tissue

epicardium

superficial layer; an integral part of the heart wall

functional syncytium

myocardium behaves as a single coordinated unit due to a gap junction electrically coupling cardiac cells

intercalated disc

specialized connections between myocardial cells containing gap junction and desmosomes

myocardium

middle layer; composed of muscle

pacemaker

sinoatrial node

quiescent period

period of total heart relaxation

stroke volume

volume of blood pumped out by one ventricle with each beat

systole

periods of contraction

vagal tone

autonomic divisions continuously send impulses to the sinoatrial node but the dominant influence is inhibitory

venous return

amount of blood returning to the heart and distending of its ventricles

ab~

departing from, away from

angin~

choked

brady~

slow

cardi~/cardio~

heart

cusp~

pointed

diastol~

stand apart

extrins~

from the outside

foram~

opening

hyper~

excess

intercal~

insert

intra~

within

macro~

large

meta~

beyond, between, transition

micro~

small

mono~

single

myo~

muscle

para~

beside, near

peri~

around

Re~

back, again

semi~

half

septum~

fence

steno~

narrow

systol~

contraction

tachy~

rapid

~able

able to, capable of

~nom

govern

~some

body

~stitia

come to stand

~tomy

to cut

What are the layers of the pericardium?

fibrous, serous, parietal layer, visceral layer

What are the layers of the heart wall?

epicardium, myocardium, and endocardium

What does sympathetic stimulation?

increases contractility

What does parasympathetic stimulation?

reduces heart rate when a stressful situation has passed

What does epinephrine do?

enhances heartrate and contractility

What does thyroxine do?

increases metabolic rate, production of body heat, enhances epinephrine and norephrine, and causes a sustained increase in heart rate

What do low levels of calcium do?

depress the heart

What do high levels of calcium do?

increase heart rate and contractility

What do high levels of potassium do?

causes heart block and cardiac arrest

What do low levels of potassium do?

make the heart feeble and arrhythmic

What causes high temperatures?

tachycardia

what causes low temperatures?

bradycardia

Describe the generalized flow of blood through the heart in relation to the pulmonary and systemic circuits

blood from the systemic circuit, vena cava, right atrium, tricuspid valve, right ventricle, pulmonary valve, pulmonary trunk, pulmonary arteries, lungs, pulmonary veins, left atrium, bicuspid valve, left ventricle, aortic valve, aorta, blood to the systemic circuit

Describe the intrinsic cardiac conducting system structure and functions

1. the sinoatrial node (pacemaker) generates impulses (P wave) 2. impulses pause (0.1) at the atrioventricular node 3. the atrioventricular bundle connects the atria to the ventricles (QRS complex) 4. the bundle branches conduct the impulses through the interventricular septum 5. the subendocardial conducting network depolarizes the contractile cell of both ventricles

arteries

move blood away from the heart

elastic arteries

thick walled arteries near the heart, aorta, and it’s major branches; largest in diameter 2.5cm to 1cm; low resistance pathways that conduct blood from the heart to medium sized arteries; inactive in vasoconstriction; pressure reservoirs expanding and recoiling as the heart ejects blood

muscular arteries

delivers blood to specific body organs; most named arteries in the body; thickest tunica media of all vessels

arterioles

smallest of the arteries, resistance vessels, minute to minute flow into the capillary beds is determined by an arteriolar diameter which varies in response to neural, hormonal, and local chemical influences

auscultatory method

1. wrap the blood pressure cuff snugly around the person's arm superior to the elbow 2. inflate the cuff until the cuff pressure exceeds systolic pressure 3. rescue cuff pressure gradually and listen with a stethoscope for sounds in the brachial artery

baroreceptor

pressure sensitive mechanoreceptors that respond to changes in arterial pressure and stretch; when stretched they send a rapid stream of impulses

capillary

smallest blood vessels; sites of exchange between blood and tissue cells

fenestrated capillary

occur in areas of active filtration or absorption and areas of endocrine hormones secretion, number of fenestrations in capillaries increases during active absorption of nutrients

sinusoid capillary

allow large irregularly shaped molecules and cells to pass; blood flows slowly; macrophages extend processes through the apertures to catch or form part of the sinusoid wall

capillary bed

interweaving networks where blood and nutrients and wastes are exchanged

capacitance vessel

veins

chemoreceptor

receptor sensitive to various chemicals; CO2, O, H+

lumen

cavity inside a tube contains blood

myogenic

physical

precapillary sphincter

a cuff of smooth muscle that acts as a valve to regulate blood flow in a capillary; controlled by local chemical conditions

pressure points

locations that can be compressed to stop blood flow into distal tissues during hemorrhages

pulse

rhythmic expansion and recoil of arteries resulting from heart contraction; can be felt from outside of the body

tunica intima

innermost layer closest to the blood

tunica media

smooth muscle cells and sheets of elastic; the middle layer

tunica externa

composed largely of loosely woven collagen fibers that protect, nourish, and anchor the vessel

vasa vasorum

nourishes external tissue of the blood vessel wall

vascular anastomoses

union or joining of nerves, blood vessels, or lymphatic vessels

vasoconstriction

narrowing of blood vessels

vasodilation

relaxation of smooth muscle and blood vessels

vasomotor tone

atrioles are almost always in a state of moderate construction

vein

brings blood to the heart

venule

small vein; 8 to 100 μm

venous reservoir

veins can store most of the body's blood at anytime

venous sinus

flattened veins with thin walls composed only of endothelium

ac~/acro~

extreme, extremity, peak

anastomoses~

come together

aneurysm

a widening

angi~

vessel

aort~

great artery

auscult~

listen

baro~

pressure

brachi~

arm

brev~

short