Cardiovascular System

Question 1

When does the heart form?

Answer 1

around week 10 of embryonic development

Question 2

What are the 4 chambers of the heart?

Answer 2

• right and left ventricles (lower)
• right and left atria (upper)

Question 3

How does blood flow through the heart?

Answer 3

• deoxygenated blood flows from the body into the right atrium which pushes it to the right ventricle which pumps it out to the lungs
• oxygenated blood returns from the lungs to the left atrium which pushes it into the left ventricle where it is pumped back out to the body via the pulmonary arteries

Question 4

Which part of the right atrium is rough?

Answer 4

the part closest to the auricle (embryonic part)

Question 5

What does the tricuspid valve allow?

Answer 5

a single direction of blood flow from the right atrium to the right ventricle

Question 6

What are the trabeculae carneae?

Answer 6

muscular ridges that help with blood flow by preventing the suction that would occur if the internal surfaces of the ventricular wall were smooth

Question 7

What are the chordae tendineae?

Answer 7

thin, cord-like tendons that connect the AV valves to the papillary muscles to prevent the valves from inverting into the atria during ventricular contraction (systlole)

Question 8

What do the papillary muscles do?

Answer 8

prevent atrioventricular valves from opening during systole

Question 9

What does the bicuspid (mitral) valve allow?

Answer 9

oxygenated blood to travel from the left atrium into the left ventricle

Question 10

What are the alternate periods of the cardiac cycle?

Answer 10

• systole (contraction and emptying)
• diastole (relaxation and filling)

Question 11

What happens during atrial contraction and ventricular relaxation?

Answer 11

blood fills the ventricles

Question 12

What happens during ventricular contraction?

Answer 12

blood is ejected from the ventricles to the outflow tracts (aorta and pulmonary trunk)

Question 13

What do the 4 valves of the heart do?

Answer 13

control the flow of blood through the heart by opening and closing the chambers in a coordinated sequence

Question 14

What are the 2 valves between the atria and ventricles?

Answer 14

tricuspid and bicuspid (mitral)

Question 15

Which valves ensure blood exits the heart correctly?

Answer 15

aortic and pulmonary semilunar

Question 16

Which of the 4 heart valves carry oxygenated and deoxygenated blood?

Answer 16

• pulmonary (deoxygenated)
• aorta (oxygenated)
• tricuspid (deoxygenated)
• bicuspid (oxygenated)

Question 17

What does contraction of the papillary muscles do?

Answer 17

pull the AV valves down and prevent blood from returning into the atria

Question 18

What are arteries that supply the heart branches of?

Answer 18

the ascending thoracic aorta

Question 19

What is the pathway of deoxygenated blood?

Answer 19

1. pools in the great, middle and small cardiac vein
2. flows into the coronary sinus
3. flows into the right atrium

Question 20

What is the pericardium?

Answer 20

a protective, fluid-filled sac that surrounds the heart with a fibrous and serous layer

Question 21

What are the functions of the pericardium?

Answer 21

• position the heart between the lungs in the chest cavity
• lubricate the surface of the heart to reduce friction when beating
• prevent overfilling

Question 22

What is the order of conduction in the heart?

Answer 22

electrical signals originate in the SA node then travel from the atria to the ventricles and pass through the AV node

Question 23

What is the bundle of His?

Answer 23

an elongated segment connecting the AV node and the left and right bundle branches of the septal crest

Question 24

What are the 5 steps of conduction in the heart?

Answer 24

1. atrial depolarisation initiated by the SA node
2. delay at the AV node to allow time for the atria to contract completely and the blood to fully fill the ventricles
3. ventricle depolarisation
4. atrial repolarisation
5. ventricular repolarisation

Question 25

What happens during ventricle depolarisation?

Answer 25

1. electrical impulse travels down the AV bundle to the apex of the heart 2. moves upwards on the walls of the ventricles to begin depolarisation 3. this triggers ventricular contraction from the bottom to allow ejection of blood upwards into the aorta and pulmonary trunk

Question 26

What is the sympathetic innervation to the heart?

Answer 26

adrenaline/noradrenaline acts on β-adrenergic receptors to increase heart rate, heart contraction and cause vasoconstriction

Question 27

What is the parasympathetic innervation to the heart?

Answer 27

ACh acts on M2 muscarinic receptors to decrease heart rate and contraction and cause vasodilation

Question 28

What are beta blockers used for?

Answer 28

hypertension and increased heart rate e.g. atrial fibrillation

Question 29

How do beta blockers work?

Answer 29

they bind to beta-receptors on the heart and vessels to prevent adrenaline/noradrenaline from binding

Question 30

What is the order of organisation in the heart wall from internal to external?

Answer 30

- endocardium - myocardium - epicardium - pericardial cavity - parietal pericardium - fibrous pericardium

Question 31

What do desmosomes do?

Answer 31

anchor adjacent cells to prevent them from separating from each other during contraction

Question 32

What is a gap junction?

Answer 32

a pathway which allows ions to pass from one cell to another, allowing electrical impulses to spread throughout the myocardium

Question 33

What causes a functional syncytium?

Answer 33

gap junctions as they allow contraction as one unit

Question 34

How do ultrasounds work?

Answer 34

sound waves bounce off tissues, organs or structures which creates echoes that are captured on a screen in real time

Question 35

Describe arteries (function, appearance, wall thickness, valves, pulsation and direction of blood flow)

Answer 35

- function - transport oxygenated blood - rounded shape - thicker walls to sustain pulsatile pressure - no valves - pulsation present - blood flows away from the heart

Question 36

Describe veins (function, appearance, wall thickness, valves, pulsation and direction of blood flow)

Answer 36

- function - transport deoxygenated blood - irregular shape - thinner walls since no need to sustain pulsatile pressure - valves to allow one way direction - no pulsation - blood flows towards the heart

Question 37

What are the 3 layers of blood vessels?

Answer 37

- tunica intima - tunica media - tunica adventitia

Question 38

What is the tunica intima?

Answer 38

endothelial lining of the lumen formed by simple squamous epithelium that contains basement membrane and loose connective tissue to support endothelial lining and also contains elastic lamina

Question 39

What does the tunica media contain?

Answer 39

- smooth muscle responsible for vasodilation and vasoconstriction (depending on ANS input) - external elastic lamina

Question 40

What does the tunica adventitia contain?

Answer 40

- own blood supply from its own vessels termed as vasa vasorum - collagen providing structural support and protection to the vessel

Question 41

How can venous blood travel from superficial veins to deep veins?

Answer 41

via perforator veins

Question 42

What is a portal system?

Answer 42

a connection in which blood passes through two sets of capillary systems before returning to the heart

Question 43

What is the first and second capillary system?

Answer 43

- first - digestive organs - second - liver

Question 44

Where does the hepatic portal vein carry blood?

Answer 44

to the liver from the intestines, spleen, pancreas, and gallbladder