L06: Heart and Cardiopulmonary Circulation

what is the outermost structure surrounding the heart

epicardium

visceral serous layer over the heart is called

epicardium

true/false: serous layer of parietal pericardium lines the body wall

false (lines fibrous pericardium)

what anchors the heart to the sternum, respiratory diaphragm, and great vessels?

fibrous pericardium

what is the sensory innervation of the pericardium

phrenic nerve (C3-5)

space between visceral pericardium and serous pericardium

pericardial sac/cavity

true/false: the fibrous pericardium expands and contracts as the heart beats

false (does not expand)

what does the ANS activate in the pericardium

production of serous fluid

blood supply to pericardium

pericardiacophrenic arteries and veins

part of pericardium that is Posterior to outflow vessels (aorta and pulmonary trunk)

transverse sinus

what are two common places for fluid to collect in the pericardium

transverse and oblique sinus

true/false: both atria in the heart contract simultaneously

true

true/false: each ventricle in the heart contracts at separate times

false (simultaneously)

which structures feed into the right atrium

superior and inferior vena cava, coronary sinus

which side of the heart pumps oxygenated blood

left

which side of the heart pumps deoxygenated blood

right

which structures feed into the left atrium

pulmonary veins

are the auricles on the anteiror or posterior side of the heart

anterior

pouch-like appendage

of atrium, helps with contraction

auricle

comb or rake-like,

muscular ridges of atrial myocardium

pectinate muscles

depression between opening

of SVC and IVC on interatrial septum, remnant of fetal shunt from right to left atrium

fossa ovalis

runs from SVC to IVC openings

on anterior wall of atrium, marks end of pectinate

muscle

crista terminalis

Internodal conduction pathway between SA and

AV nodes, marks location of SA node

crista terminalis

where blood used by

the heart returns

coronary sinus

“meat struts,”

muscular ridging of myocardium

trabeculae carnae

nipple-like

projections of myocardium, connected to

AV valve leaflets via chordae tendineae,

keep AV valve closed during contraction

papillary muscles

“heartstrings,”

connect papillary m.m. and AV valve

leaflets

chordae tendineae

band of muscle

transmitting AV bundle fibers from IV

septum throughout base of ventricle

moderator band

R atrioventricular valve,

three fibrous leaflets

tricuspid valve

semilunar valve to

pulmonary trunk

pulmonary valve

remnants of foramen

secundum/interatrial fetal

shunt

Valve of foramen ovale

which ventricle has thicker walls

left

thin part

of interventricular septum located

Superior Vena Cava

near aortic valve, common site of

Right Ventricle

ventricular septal defects (VSD)

membranous septum

Left

atrioventricular valve, two leaflets

mitral/bicuspid valve

semilunar valve to

aorta

aortic valve

what prevents the valves in the heart from collapsing

fibrous rings of dense collagen that form scaffolding for the valves

what is the only way that electrical impulses can travel between the atria and ventricles

AV bundle (of His)

what separates and electrically isolates the atria from the ventricles

fibrous skeleton of the heart

during ventricular systole, are the AV valves open or closed

closed

what holds the AV valves closed

chordae tendinae and papillary muscles

during atrial systole, are the AV valves open or closed

open

where is the pulmonary semilunar valve located

between right ventricle and pulmonary trunk

where is the aortic semilunar valve located

between the left ventricle and the aorta

during ventricular systole, are the semilunar valves open or closed

open

during atrial systole, are the semilunar valves open or closed

closed

purpose of semilunar valves

Keeps blood from flowing back into the ventricle

purpose of AV valves

keeps blood from flowing back into the atria

what happens during ventricular diastole

ventricles relax, relax, semilunar valves are closed, atrial systole, AV valves are open

what happens during ventricular systole

ventricles contract, semilunar valves open, atrial diastole, AV valves are closed

what are the first branches off of the aorta

right and left coronary arteries

what are the two branches of the left coronary artery

anterior interventricular and circumflex branches

which branch of the LCA supplies the anterior ventricles and the interventricular septum

anteior interventricular branch

which branch of the LCA supplies the left atrium and ventricle and potentially the SA node

circumfelx branch

what are the three branches of the right coronary artery

atrial, marginal and posteior interventricular

which branch of the RCA supplies the atria and SA node

atrial

which branch of the RCA supplies the right ventricle

marginal branch

which branch of the RCA supplies the posterior walls of the ventricles, interventricular septum, and AV node

posterior interventricular branch

nearly all of the hearts venous return epties into where

coronary sinus

where and how does the coronary sinus empty into

the right atrium via the interventricular opening

which vein drains the anterior interventricular septum and left ventricle

great cardiac vein

which coronary vein drains the posterior interventricular septum and ventricles

middle cardiac vein

which coronary vein drains the lateral right ventricle and right atrium

small cardiac vein

specialized cardiac

cells that generate impulses, congregate

in nodes

pacemaker cells

bundled,

unidirectional, conduction pathways,

initiate and coordinate excitation and

contraction of myocardium

conduction fibers

which node is considered the pacemaker of the heart, initiates the action potential and controls heart rate and sends impulses to the atria and AV node, intiating atrial systole

sinoatrial node

what is the SA node’s resting BPM range

60-100

which division of the nervous system controls the SA node

autonomic

where is the SA node located

base of the superior vena cava where the crista terminalis starts

where is the atrioventricular node located

between the coronary sinus and septal cusp of tricuspid valve

AV node function

convey’s the SA node’s signal to the atrioventricular bundle (of his)

true/false: the AV node can fire without the SA node’s signal

true

what is the intrinsic rate of the AV node

40-60 bpm

which bundle conducts impulses from the SA node to the AV node through the walls of the right atrium

internodal bundles

which bundle crosses over the interatrial septum to conduct impulses from the SA node to the left atrium

interatrial bundle

which bundle splits into right and left branches along the interventricular septum, ending in purkinje fibers the branch throughout the ventricle walls

atrioventricular bundle (of His)

AV bundle of His function

initiate and coordinate contraction of ventricles from the apex up

trace a drop of blood from the right atrium to the aorta (including valves)

right atrium, tricuspid valve, right ventricle, pulmonary semilunar valve, pulmonary trunk, L/R pulmonary artieries, lungs, pulmonary veins, left atrium, bicuspid valve, left ventricle, aortic semilunar valve, aorta

which structure allows for maternal blood to come close to fetal blood, allowing for gas and metabolite exchange without blood cells actually mixing, and acts as the liver and lungs for the fetus so that circulation can bypass those organs

placenta

which vein carries blood from the placenta to the liver, later branching and continuing as the ductus venosus to the inferior vena cava

umbilical vein

true/false: the umbillical vein carries deoxygenated blood

false (oxygenated)

how does deoxygenated fetal blood get returned to the placenta

internal iliac artery to the umbilical artery

how does fetal blood get from the right atrium to the left atrium

interatrial septum formed by foramen ovale and foramen secundum

which two holes make up the interatrial septum in the right and left atria, respectively

foramen ovale for right and foramen secundum for left

how does fetal blood get from the right ventricle to the aorta?

through the pulmonary trunk, then to the ductus arteriosus, then into the aorta

what happens when a baby takes its first breath

pressure decreases in lungs and they fill with air, hormonal and nervous signals clamp off ductus arteriosus, the massive pressure in the left atrium slams the foramen ovale and secundum shut

what does the umbilical vein become post-natally

round ligament of the liver

what does the ductus venosus become post-natally

ligamentum venosum

what does the foramen ovale/secundum become post-natally

fossa ovalis

what does the ductus arteriosus become post-natally

ligamentum arteriosum (betweek the pulmonary trunk and aorta)

what does the umbilical arteries become post-natally

medial umbilical folds and gives off arteries to the bladder, closing off at the body wall

what are the responsibilities of the postganglionic fibers to the heart and lungs in the sympathetic nervous system

increase HR, force of contraction, and minimally vasoconstrict coronary vessels

what overrides the vasoconstriction of coronary vessels caused by sympathetic postganglionic fibers and why

adenosine relased by myocytes because they are needed to keep oxygen flowing to the myocardium

what are the responsiblities of parasympathetic innervation in the heart

decrease HR and force of contraction, vasodialate coronary vessels

which side of the vagus nerve supplies the SA node

right

which side of the vagus nerve supplies the AV node

left

true/false: visceral sensory system is part of the ANS

false

which sensory system carries sensation from organs to the CNS

visceral

what are some sensations transmitted by the visceral sensory system

bloating, distension, change in BP, dyspnea, nausea

what path does the visceral sensory system take to get back to the the dorsal horn

sympathetic chain, white ramus communicans, mixed spinal nerve, dorsal root, dorsal horn

what is the cause of reffered pain from viscera

visceral sensory neurons enter the spinal cord at the same place as somatic sensory neurons and can get confused as somatic pain (also brain has a better map of body wall and can locate somatic pain more precisely than visceral pain)