heart

Question 1

the heart orientation (division location, base and apex orientation)

Answer 1

inferior-middle mediastinum

base:
proximal
broad, towards right shoulder
left (and right) atria

Apex:
Distal
Pointed
Mid-clavicular line + 5th intercostal space
left ventrical

Question 2

heart chambers overview (4)

Answer 2

2 atria (base) - receives blood

2 ventricals (apex) - pumps blood

right side: deoxy blood, flow directed to the lung

left side: oxy blood, flow directed to the body

Question 3

fossa ovalis

Answer 3

foramen ovale –> fossa ovalis

covered with CT
interatrial septum
fetal blood flow

Question 4

fetal heart

Answer 4

circulation bypasses the lungs

foramen ovale
- hole connecting right + left atria

Ductus arteriosus
- artery connecting pulmonary artery + aorta
- superior mediastinum

both close after birth (after first breath) by CT

Question 5

foramen ovalis turns into

Answer 5

fossa ovalis

Question 6

ductus arteriosus turns into

Answer 6

ligamentus arteriosum

Question 7

blood pathway in heart (7)

Answer 7

1. blood comes back to heart via superior and inferior vena cava into right atrium
2. passively drain into the right ventrical except for the last little bit which the pectinate musle contract to push the rest through
3. right ventrical contracts and pushes blood up and out past semilunar valve and pulmonary trunk and straight to lungs
4. blood is reoxgynated and come back into pulmonary arteries into left atrium
5. passively fills left ventrical by passing through the bicupsid/left atrioventricular valve
6. left ventrical contracts - pulls on papillary muscles and hold the AV valve close
7. blood flows up trhoguh the ascending aorta, passing the semilunar valve and pushing it up and out to the body

Question 8

external heart - anterior + posterior chambers

Answer 8

ant: right atrium, right ventricle

post: left and right ventricle

Question 9

external heart - anterior + posterior sulci

Answer 9

ant: coronary (AV) right, interventricular

post: coronary (AV) left, posterior interventricular

Question 10

external heart - anterior + posterior vessels

Answer 10

ant: superior vena cava, ascending aorta, pulmonary trunk, coronary arteries + veins

post: inferior vena cava, pulmonary veins, coronary arteries and veins

Question 11

what structure is only found on the ANTERIOR external heart

Answer 11

ligamentum arteriosum

Question 12

primary coronary/cardiac blood vessels - left and right

Answer 12

Left: coronary, circumflex, anterior interventricular

right: coronary, posterior interventricular

Question 13

endocardium

Answer 13

deepest heart layer

inner myocardial surface
lines chambers, valves

simple squamous epithelium + areolar tissue

continuous with endothelium of great vessels

Question 14

myocardium

Answer 14

middle layer of heart layers

heart muscle
- concentric layers
- blood vessels + nerves
- thicker on left

striated - similar to skeletal muscle

arranged in spiral bundles - links all parts of the heart together

intercalated discs
- joins muscles fibres end to end
- contains gap juntions
- allows rapid spread of excitation

Question 15

epicardium

Answer 15

outer surface
- is the visceral layer of serous pericardium

areolar tissue - closet to myocardium

mesothelium
- closest to pericardial cavity
- secretes serous fluid

Question 16

pericardium

Answer 16

sac of CT covering the heart

pericardial cavity - serous fluid, low friction

parietal serous pericardium
- mesothelium (inner)
- areolar tissue (outer)
- continuous with visceral serous layer at the root of the great vessels

parietal fibrous pericardium
- DFCT

Question 17

(parietal) fibrous pericardium

Answer 17

con-shaped “bag”
base —> diaphragm

apex continuous with adventitia of great vessels

limits distention (expansion of heart)

Question 18

blood flow in

Answer 18

ventricular contraction
ejection of blood
CARDIAC OUTPUT

Question 19

blood flow out

Answer 19

capillary flow
controlled by resistance of arteries

Question 20

balance flow in/out determines pressure - changes include…

Answer 20

increase CO = increase inflow

increase resistance = decrease outflow

increase arterial volume and pressure

Question 21

cardiac output formula

Answer 21

CO = SV x HR

Question 22

echocardiography

Answer 22

non-invasive technique to measure heart function

uses sound waves to take live images of the heart as it contracts
can also track the rate of blood movement through the heart

Question 23

the RyR forms…

Answer 23

large protein complez with accessory proteins on the SR membrane

• can be modified (eg phosphorylation by kinases)

Question 24

at low levels, RyR…

Answer 24

is largely unmodified - Ca release is slow

Question 25

as activity increases RyR...

Answer 25

is modified to increase pore size, allowing mor Ca to move into cytosol

Question 26

at the highest levels, RyR...

Answer 26

is heavily phosphorylated, releasing Ca freely and staying open for a long period of time

Question 27

structure of RyR

Answer 27

large tetrameric channel that spans SR membrane Ca moves from SR to cytosol through RyR exists as a complex with accessory proteins and can be modifie

Question 28

spontaneous Ca Leaks and Ca sparks

Answer 28

release or leak of Ca through RyR that is NOT induced as part of the normal conduction pathway

Question 29

increasing stress leads to...

Answer 29

more calcium leaks during stress, we want lots of calcium release through RyR for a strong, fast heartbeat.. but makes calcium leaks more likely

Question 30

gap junctions and spreading the impulse

Answer 30

along conduction pathway - between electrical and contractile cells - between contractile cells increased speed of the impulse throughout the heart millions of cardiac cells = a functional syncytium

Question 31

normal electrical conduction in the heart

Answer 31

propagation of the action potential is uni-directional stimulated tissue has a refractory period (where tissues cannot be re-stimulated) prevents action potential from moving backwards

Question 32

compliance =

Answer 32

ΔV/ΔP

Question 33

vein vs artery compliance

Answer 33

vein = large vol, small P artery = small vol, large P

Question 34

whats the driving force for blood floow

Answer 34

large difference in pressure between the arterial and venous sides

Question 35

fick's law (not the formula just the concept behind it)

Answer 35

diffusion defines the rate of movement for gasses across the blood-air barrier flux = movement across membrane over time D = diffusion constant - molecules have their own A = area - alveoli maximise surface area - also close to capillary wall T = thickness of barrier (thicker = slower) P1-P2 = pressure difference - changes all the time big difference = bigger energy demand (stress, exercise) = bigger flux small difference = flux relatively slow (relaxed)