APK2100C Exam 4 (heart + blood vessels + respiratory)

why is the heart referred to as a muscular double pump

there are two different blood flow circuits in the heart: systemic and pulmonary

what half of the heart is associated with the pulmonary circuit

left

what half of the heart is associated with the systemic circuit

right

describe the location of the heart within the thoracic cavity

protected by ribcage

heart sits slightly left of midsternal line

heart sits on anterior side of thoracic cavity within mediastinum

describe the heart shape

“upside down, back leaning cone”

apex of the heart inferior surface, sits on left

describe the surface anatomy of the heart

between lungs

dorsal to sternum

ventral to vertebral column

superior to diaphragm which is the separator btw thoracic and abdominal cavity

what are the 3 layers of the heart wall from superficial to deep

epicardium, myocardium, endocardium

epicardium

visceral layer of pericardium (serous membrane)

most superficial heart wall layer

myocardium

cardiac muscle tissue

middle layer of the heart wall

endocardium

lines the chambers and covers the valves

simple squamous epithelia

deepest layer of the heart wall

what are the 3 layers of the pericardium

fibrous pericardium, parietal pericardium, visceral pericardium

fibrous pericardium

adheres to the diaphragm and the roots of large vessels

adheres heart in place, prevents movement of the heart

most superficial layer of the pericardium

parietal pericardium

adheres to inner surface of the fibrous pericardium

parietal layer of serous membrane

middle layer of pericardium

visceral pericardium

epicardium

deepest layer of the pericardium

what is the shared layer between the heart wall and the pericardium

epicardium/visceral layer

what are all the layers of the heart wall and pericardium superficial to deep

fibrous pericardium, parietal pericardium, epicardium/visceral pericardium, myocardium, endocardium

atria

superior receiving chambers

smaller

ventricles

inferior pumping chambers

larger/thicker walls

what are the atria seperated by

interatrial septum

what are the ventricles seperated by

interventricular septum/myocardium

what type of blood and from where does the right atrium recieve

oxygen poor blood from systemic circuit

what type of blood and from where does the left atrium recieve

oxygen rich blood from pulmonary circuit

what type of blood and from where does the right ventricle pump

oxygen poor blood to pulmonary circuit

what type of blood and from where does the left ventricle pump

oxygen rich blood to systemic circuit

why do the atria have thinner walls compared to the ventricles

the atria have thin walls because they are receiving chambers and therefore only need small contractions

the ventricles must pump blood upward, against the work of gravity, into its according circuit

why is the myocardium of the left ventricle thicker than the right ventricle

the left ventricle belongs to the systemic circuit and therefore more force is required to pump the blood to the entire body, requires higher-pressure

the right ventricle that pumps the pulmonary circuit is short and low-pressure comparatively; therefore, the walls are not as thick

coronary sulcus

groove that wraps around entire heart circumference, separates atria from ventricles

houses blood vessels that nourish the heart

inferior to auricles

anterior interventricular sulcus

groove between ventricles

posterior interventricular surface

groove between ventricles

pulmonary trunk

receives oxygen poor blood from contraction of right ventricle

bifurcates into L + R pulmonary arteries

why are there 2 pulmonary arteries

oxygen poor blood being carried away from the heart must go to EACH lung for oxygenation

pulmonary arteries

oxygen poor blood carried away from the heart to the lungs on pulmonary circuit

pulmonary veins

carries oxygen rich blood from lungs to left atrium

why are there 4 pulmonary veins

veins target specific lobes of lungs

pectinate muscles

anterior portion of atria that is ridged, “comb-like” surface of otherwise smooth-walled atria

contractile efficiency

crista terminalis

c-shaped ridge that runs between the openings of the superior and inferior vena cava on the posterior wall of the right atrium

fossa ovalis

in utero, hole opens to left and right atrium

hole closes once baby is born

fossa ovalis = divet that is left after the hole closes

trabeculae carneae

both anterior and posterior surfaces of the ventricles are rough networks of muscle tissue

papillary muscles

mounds/bumps/nipples on inferior surface of ventricles

cardiac muscle attached to chordae tendineae

chordae tendineae

tendinous cords attached to the AV valves of the left and right ventricles

what are the AV valves

valves separating the ventricles from the artria

R- tricuspid valve

L- mitral valve

what are the semilunar valves

valves separating the ventricles from the major arteries that pump blood away from the heart

R- pulmonary valve

L- aortic valve

structure of AV valves

as blood volume in the ventricle increases, blood pushes on valve

papillary muscles contract, chordae tendinae pulled, pulls valves taught

prevents backflow and prolapse

structure of semilunar valves

little half-moon “cups” that rest against each other

contraction of ventricle shoots blood through valve “barn door”

if any backflow, cups would catch blood preventing it from seeping back into ventricle

explain pulmonary circuit

oxygen poor blood returns from body to right atrium in SVC, IVC (or from heart in coronary sinus)

right atrium fills and blood flows through OPEN tricuspid valve into right ventricle

right ventricle fills, papillary muscles contract pull chordae tendinae CLOSE tricuspid valve, right ventricle contracts

blood travels through pulmonary semilunar valve to pulmonary trunk where it bifurcates into left and right pulmonary arteries

left and right arterioles, pulmonary capillaries, oxygen enters blood, carbon dioxide leaves blood

venule, 4 pulmonary veins carry oxygen rich blood back to heart

explain the systemic circuit

via the 4 pulmonary veins oxygen rich blood into left atrium

left atrium fills and blood travels through OPEN mitral valve into left ventricle

left ventricle fills, papillary muscles contract to pull chordae tendinae CLOSE mitral valve, left ventricle contracts

blood travels through aortic semilunar valve into aorta, arteries, arterioles,

capillaries, oxygen leaves blood, carbon dioxide concentration increases

oxygen poor blood returns venule, veins, SVC,IVC

superior vena cava

oxygen poor blood from systemic regions above heart back into right atrium

inferior vena cava

oxygen poor blood from systemic regions below heart back into right atrium

aorta

oxygen rich blood to systemic circuit

sinoatrial (SA) node

“pacemaker”, cluster of cardiac muscle cells responsible for electrical signals

signals transverse from right to left

at base of R atrium

atrioventricular (AV) node

specialized cardiac muscle cell that detects signal and relays signal to AV bundle located in interventricular septum

AV bundle/bundle of his

bifurcates into 2 as it approaches apex (one per side of heart), curves up into ventricular walls

splits further into purkinje fibers

coronary vessels

supply heart with oxygen rich blood and nutrients

coronary veins

drains oxygen poor blood from the heart myocardium after the heart has already used it

coronary arteries

deliver oxygen rich blood to heart myocardium

what does the left coronary artery bifurcate into

circumflex artery

LAD

circumflex artery

curves around to the posterior

sits below L aorta

coronary sulcus

left anterior descending artery (LAD) / anterior interventricular artery

sits in anterior interventricular sulcus

what does the right coronary artery bifurcate into

posterior interventricular artery

right marginal artery

where does the right coronary artery sit

coronary sulcus

what areas of the heart do the right marginal and right posterior interventricular artery provide

right atrium

most of right ventricle

what areas of the heart does the left anterior descending artery supply

interventricular septum

anterior walls of right and left ventricle

where is the great cardiac vein located

anterior interventricular sulcus

where is the middle cardiac vein located

posterior interventricular sulcus

where is the small cardiac vein located

inferior right maragin

what do both the small, middle, and great cardiac vein dump into

coronary sinus

true or false: the great cardiac vein curves around to the posterior side of the heart into the coronary sinus

true

true of false: the coronary sinus bifurcates into the middle cardiac vein and the small cardiac vein

true

true or false: the coronary sinus dumps oxygen poor blood into the right atrium

true

besides the lumen, what are the 3 main layers that both arteries and veins share

tunica extrerna

tunica media

tunica intima

compare the size of the tunica externa between arteries and veins

veins > arteries

compare the size of the tunica media between arteries and veins

arteries > veins

compare the size of the tunica intima between arteries and veins

about the same

what is the tunica externa made of

connective tissue, collagen fibers

what is the tunica media made of

smooth muscle, elastic fibers

what is the tunica intima made of

simple squamous epithelia, subendothelial layer

arteries

carry blood away from heart

veins

carry blood to heart

storehouse for blood, 65% is in veins at any given moment

low pressure system

capillaries

network (functional redundancy), site of nutrient and gas exchange

simple squamous epithelia, basement membrane

diameter of single blood cell

vasa vasorum

blood vessels supplying large vessels

largest to smallest type of arteries

elastic arteries, muscular arteries, arterioles

elastic arteries

large lumens, lots of elastin

allows for expansion to accommodate blood flow

muscular arteries

thick tunica media, allows for vasoconstriction

arterioles

lead into capillaries

where does regulation of blood flow occur

arterioles

explain what characteristics of arterioles allow for vasoconstriction and vasodilation

in arteriolar wall smooth muscle is always at partial state of contraction (smooth muscle tone)

allows for relaxation = vasodilation, increases blood flow

allows for further contraction = vasoconstriction, decreases blood flow

why is smooth muscle tone important

if baseline was fully relaxed, there would be no way to further increase lumen size to increase blood flow

what is the role of smooth muscle in a capillary

precapillary sphincters regulates blood flow through capillary bed

isolated to mesenteric vasculature (intestines)

what happens when the pre-capillary sphincters contract

blood flow is restricted through some of the network, no blood through “true” capillaries/network

blood forced through the metarteriole, into the the thoroughfare channel of the venule, in process called vascular shunt

what is the name of the arteriole leading into a capillary bed

terminal arteriole

what is the name of the venule following a capillary bed

post capillary venule

what are the 4 methods of molecule permeability of the capillaries

diffusion through endothelial membranes

intercellular clefts

pinocytotic vesicles

fenestrations

why is the blood brain barrier an exception

no fenestrations or clefts

complete tight junctions that seal space between cells, tight regulation of materials

glucose is “ushered” across walls

intercellular clefts

spaces between epithelial cells

fenestrations

holes in endothelial cell layer

3 types of capillaries

continious, fenestrated, sinusoid

continious capillary

epithelial cells are like jigsaw puzzles pieces

seams w/ each other, NO gaps

small intracellular gaps

least permeable

fenestrated capillary

“puzzle pieces of swiss cheese”

epithelial cells are like jigsaw puzzle pieces

seams w/ each other, NO gaps

small intracellular caps

pores/fenestrations in epithelial cells increase permeability

sinusoid capillaries

epithelia has holes

epithelial cells are irregularly shaped

large intracellular clefts

basement membrane not continious (incomplete)

most permeable

where can you find continious capillaries

skin

muscle