Cardiovascular system

Question 1

systems of the heart

Answer 1

Blood vascular - closed supply / drainage

Lymphatic vascular - open entry drainage

Question 2

Organisation of cardiovascular system

Answer 2

Supply side - arteries, situated deep in trunk for protection
Exchange network - capillaries ( continuous, fenestrated and sinusoidal )
Drainage - Veins ( deep and superficial ), lymphatics

Question 3

Heart structure - right and left atrium

Answer 3

right atrium - receives deoxygenated blood ( superior and inferior vena cava, coronary sinus )
Left atrium - receives oxygenated blood ( 4 pulmonary veins )

Question 4

what are the 4 layers of the heart wall ?

Answer 4

Endocardium - squamous epithelium, purkinje fibres
Myocardium - thicker on left than right
Epicardium - visceral pericardium
Pericardium - fibrous ( visceral and parietal layers )

Question 5

what are the heart valves and what do they do?

Answer 5

Atrioventricular valves ( AV ) - prevents back flow into atria, right = tricuspid, left = bicuspid ( mitral )

Semilunar valves - prevent back flow into the ventricles, right = pulmonary, left = aortic

controlled b chordae tendindzd

Question 6

What are the phases of the heart ?

Answer 6

Diastole - filling phase ( AV open, semilunar shut )

Systole - ejection phase ( AV shut, semilunar open )

Question 7

How does the cardiac circulation work?

Answer 7

Right coronary artery - supplies right ventricular wall
Left coronary artery - branches towards the left ventricle
Circumflex artery - supplies the posterior and left lateral side of heart
Small cardiac vein - drains right side of the heart
Great cardiac vein - drains left side of the heart
Coronary sinus - drains into the right atrium

Question 8

cardiac muscle cell structure

Answer 8

striated, interconnected via intercalated disks
Adhesion belts - link actin to actin ( vertical portion )
Desmosomes - link cytokeratin together, fuse two skeletons together
Gap junctions - communication, horizontal
Creates synchronisation between the cells

Question 9

what is the structure of a blood vessel ?

Answer 9

Tunica intima
Tunica media
Tunica adventitia

Question 10

What is the tunica intima ?

Answer 10

Simple squamous epithelium
Sub-endothelium (loose FCT)
Internal elastic lamina ( well developed in arteries but not in veins )

Question 11

What is the tunica media ?

Answer 11

Smooth muscle
Variable content of connective tissue fibres
thickness proportional to vessel diameter and blood pressure ( thinner in veins thicker in arteries )
Tunica Adventitia ( often the thickest layer ) - Loose FCT, high content of collagen, in larger vessels adventitia contains the vasa vasorum

Question 12

What is the function and demand of the capillaries ?

Answer 12

they are the site of exchange between blood and tissue

needs: thin walls, large surface area and slow, smooth blood flow

Question 13

What are the capillary structures ?

Answer 13

Continuous - continuous cellular barrier
Fenestrated - leaky, physical openings in the cells ( some things can pass through ), basement membrane is still in tact
Sinusoidal - very leaky, lots of fenestrations, basement membrane incomplete, RBC can’t leave

Question 14

What is the lymph vascular system ?

Answer 14

Its function is to drain excess tissue fluid and plasma proteins
filter foreign material
screen for foreign antigens
absorb fat from intestine and transport to blood

Question 15

What is the structure of a lymphatic vessel ?

Answer 15

large fingerlike projections that sit amongst capillaries
lacteals rain fat-laden lymph into collecting vessels called cisterns chyli
larger thin walled collecting vessels have numerous valves to prevent back flow

Question 16

Drainage system

Answer 16

right Side of face, neck shoulder, chest and upper limb all drain into the right subclavian vein
Everything else into the left subclavian vein

Question 17

Cardiovascular circuits

Answer 17

Systemic - goes everywhere ( left )

Pulmonary - goes to lungs then back to the heart (right)

Question 18

How do the contractions of the heart work / occur ?

Answer 18

Atria contract first and then the ventricles ( valves open and close to direct blood )
Before heart beat - everything is relaxed ) valves closed )
atria contract - AV open, blood pushed from atria to the ventricles
Atria relax and ventricles contract - AV closed, semilunar open, blood ejected into the body
Ventricles then relax - valves closed

Question 19

What is the cellular mechanism of cardiac contraction ?

Answer 19

Most abundant proteins = actin and myosin
Thick and thin filaments
Calcium binds them and creates a contraction
Every muscle fibre contracts
extent of cross bridges is not maximised at rest
Max contraction = max calcium

Question 20

Circuit pressures?

Answer 20

Pulmonary circuit has a much lower pressure
Pulse pressure is the difference between systole and diastole
Mean pressure - always slightly lower than midway

Question 21

Pulmonary circuit

Answer 21

Has less resistance than the systemic circuit

more pressure goes into the blood that goes to the systemic circuit instead of the pulmonary circuit

Question 22

Blood flow calculation

Answer 22

Q = change in P / R 
Q = flow 
P = pressure difference 
R = resistance

Question 23

What are contractile cells ?

Answer 23

striated appearance

focus on contracting the heart

Question 24

What are electrical cells ?

Answer 24

pale

move electrical signal from cell to cell as quickly as possible