Anatomy of Heart

Question 1

where is the heart located

Answer 1

in thorax between lungs
protected by ribs and sternum
lies between ribs 2-5 (apex in the 5th intercostal space

Question 2

what is the heart covered by

Answer 2

pericardium

Question 3

what is the fibrous pericardium composed of and what does this say about its properties?

Answer 3

outer fibrous layer - inelastic (dense connective tissue)
fuses to the diaphragm and with great vessels

prevents overfilling of heart and anchors it

Question 4

what is the serous pericardium made up of and what does this say about its properties?

Answer 4

two layers of serous membrane - parietal (lines the inner lining of fibrous pericardium) and visceral (or the epicardium - adheres to surfacce of heart)

between these layers = pericardial cavity
contains pericardial fluid = prevents friction

Question 5

what happens if the pericardial fluid overfills (or any fluid overfills in the heart itself)?

Answer 5

pushes the perietal layer outwards and caught against fibrous pericardium

cardiac tamponade - heart stops beating

Question 6

layers of the heart and what muscle its made out of

Answer 6

endocardium (inner) - endothelium
myocardium (biggest) (middle) - cardiac muscle
epicardium (outer) = visceral pericardium

Question 7

vessels connected to the right atrium

Answer 7

superior vena cava
inferior vena cava
pulmonary trunk - and pulmonary arteries

Question 8

vessels connected into left atrium

Answer 8

pulmonary veins

Question 9

what causes the rough inner surface of the heart

Answer 9

bundles of muscle fibres
called trabeculae carnae (in ventricles)
called pectinate muscles (in atria

Question 10

what electrically seperates the atria and ventricles

Answer 10

bands of fibrous connective tissue
aka fibrous skeleton of the heart

encircles the pulmonary trunk and aorta

heart valves are suspended from it

Question 11

what are the names of the atrioventricular valves

Answer 11

tricuspid (right)
bicuspid/mitral (left)

Question 12

where are the semilunar valves based

Answer 12

pulmonary
aorta

both pump blood up and out so it needs valves

Question 13

function of papillary muscles

Answer 13

splits off into chordae tendinae
contraction of these muscles after the pressure increases in the ventricle
= prevents eversion of the valves = thf prevents backflow of blood in atria

(NOT OPENING AND CLOSING VALVES- that happens with pressure naturally)

Question 14

how do the semilunar valves work

Answer 14

opened by force of blood as ventricles contract

blood flows backwards in aorta/pulmonary trunk

this pools up in cusps and forces them shut

Question 15

coronary circulation - what stage must blood be delivered to heart

Answer 15

during ventricular relaxation (when contracted, all muslces are squeezed and vessels compressed)

aided by semilunar valves - when heart contracts, SL open - covers opening to the coronary vessels

when heart relaxes - exposes ostium of coronary vessels

Question 16

name the 2 vessels that branch off the left coronary arteries

Answer 16

• anterior interventricular/descending (goes down) (meets the posterior interventricular)
• cicumflex(wraps around)

Question 17

name the vessels that branch off the right coronary artery

Answer 17

• marginal (runs along right ventricle)
• posterior interventricular (runs around back of heart) (meets the anterior interventricular)

Question 18

why is it important that 2 different interventricular arteries are supplying the same area)

Answer 18

if one becomes blocked, then another one can take over

Question 19

what is the main coronary vein that drains into the right atrium

Answer 19

coronary sinus

Question 20

which veins run into the coronary sinus?

Answer 20

great (runs with ant IV artery), middle (runs with post IV artery) and small (runs with marginal)

Question 21

which cardiac veins run directly into the right atrium

Answer 21

anterior cardiac vein

Question 22

what type of cells does the cardiac conducting system consist of?

Answer 22

non-contractile cells

Question 23

pathway of the conducting system

Answer 23

sinoatrial node
atroventricular node
AV bundle (bundle of His) (slows down impulse)
Right &Left bundle branches
purkinje fibres

Question 24

why is foetal circ different from normal

Answer 24

O2 and nutrients recieved from placenta via umbilical vein

lungs annd liver non functioning so they need to be bypassed

Question 25

where does the umbilical vein running from and to

Answer 25

blood rich in O2 from placenta
goes through ductus venosus (to bypass the liver)
to inf vena cava into heart

Question 26

which circulatory shortcut in foetuses bypass the right ventricle and pulmonary system

Answer 26

Foramen Ovale
connects the right and left atria
so blood flows from right ->left
rather than down into ventricle and up and out

Question 27

which circulatory shortcut in foetuses bypass the pulmonary system and left side of heart

Answer 27

ductus arteriosus

connects pulmonary trunk to aorta

so instead of blood going to lungs (which wouldnt happen anyway cuz lungs are collapsed and high pressure) the blood goes to aorta

Question 28

which circulatory shortcut in foetuses bypass the liver

Answer 28

ductus venosus

connects umbilical vein to inf vena cava

Question 29

newborn 1st breath: what happens when lungs expand

Answer 29

blood rushes into pulmonary circulation

O2 levels rise

ductus arteriosus is constricted

Question 30

newborn 1st breath: what happens when left atrium pressure rises

Answer 30

foramen ovale closes

Question 31

newborn 1st breath: what happens when umbilical cord tied

Answer 31

umbilical vessels are closed
ductus venosus fibroses

Question 32

newborn 1st breath: ductus venosus into?

Answer 32

ligamentum venosum

Question 33

newborn 1st breath:: foramen ovale into?

Answer 33

fossa ovalis

Question 34

newborn 1st breath: ductus arteriosus into?

Answer 34

ligamentum arteriosum