Lecture 5

Question 1

What is the role of the Atrioventricular (AV) Valve?

Answer 1

Controls flow from the Atrium to the ventricle and prevents blood from returning to the Atrium during ventricular contraction

Question 2

What is the role of the semilunar valve?

Answer 2

Control flow from the ventricle to the outflow arteries and prevent blood from flowing backwards.

Question 3

What is the AV valve on the right side of the heart called?

Answer 3

Tricuspid valve

3 leaflets

Question 4

What is the AV valve on the left side of the heart called?

Answer 4

Bicuspid (mitral) valve.

2 leaflets

Question 5

What happens during the Diastole phase of the cardiac cycle?

Answer 5

Filling phase, the heart is relaxed as blood fills the ventricular chambers from the atrial chamber

Question 6

What are the AV valve doing during the diastole phase?

Answer 6

The tricuspid and mitral valves are open during thi phase to allow blood to flow through from the atrium into the ventricle.

Question 7

What are the semilunar valves doing during the diastole phase?

Answer 7

They are shut in order to prevent blood from flowing back ventricles.

Question 8

What happens during the ventricular Systole phase of the cardiac cycle?

Answer 8

The Ventricles are contracting, this exerts pressure on the blood inside the ventricle to push the. blood out.

Question 9

What are the AV valves doing during the systole phase ?

Answer 9

They are closed so that the pressure resulting from contraction isn’t able to push blood back into the atrium.

Question 10

What are the semilunar valves doing during the systole phase ?

Answer 10

They are open so that the pressure resulting from contraction is able to push the blood out into the outflow artery

Question 11

What is the role of semilunar valves?

Answer 11

Determine the passage of blood between the ventricles and main arteries

Question 12

What is the semilunar valve on the right side of the heart called?

Answer 12

Pulmonary semilunar vale

three cusps

Question 13

What Is the semilunar valve on the left side of the heart called?

Answer 13

Aortic semilunar valve (3 cusps)

Question 14

How are AV valves and SL valves different structurally?

Answer 14

SL valves are much smaller because they are passing pressurised blood whereas the AV valves are larger because they are passing blood that under of a lower pressure and moving slower.

Question 15

What is a papillary muscle?

Answer 15

A fingerlike projection of the ventricular wall, the tip of the muscle has little tendinous cords which are attached to the free edge of the AV leaflets. When pressure increases in ventricular chambers, the papillary muscles develop tension on the chordae tendineae which prevents the leaflets from slamming shut.

Question 16

What are coronary arteries?

Answer 16

Branches that come off the root of the aorta and branch back straight onto the heart. Their role is to supply oxygenated blood to the heart.

Question 17

Location of the right coronary artery?

Answer 17

On the right side of the aorta, just above the aortic valve\ve. Runs in the epicardium in a grove between the right atrium and right ventricle

Question 18

Location of the left coronary artery?

Answer 18

On the left side of the aorta, goes a short distance then branches into the interventricular artery.

Question 19

Location of the interventricular artery?

Answer 19

Branches off the left coronary artery and runs over the interventricular septum

Question 20

Location of the circumflex artery?

Answer 20

Runs in left coronary groove in the epicardium between left atrium and left ventricle, runs around to the margin and posterior.

Question 21

What is the role of cardiac veins?

Answer 21

Drains blood back

Question 22

What side of the heart is drained by the small cardiac veins?

Answer 22

Right side

Question 23

What side of the heart is drained by the great cardiac vein?

Answer 23

Left side

Question 24

What is the coronary sinus?

Answer 24

Receives the deoxygenated blood that is being drained back by the cardiac veins and drains into the right atrium so that it can be sent back into the pulmonary circuit for reoxygenation

Question 25

Explain why capillaries have such a specific structure?

Answer 25

They are roughly the diameter of one blood cell so that red blood cells have to travel single file and as close to the wall s possible to make gas exchange easier

Question 26

What is the function of cardiac muscle?

Answer 26

Beating of the heart

Question 27

Characteristics of a cardiac muscle cell?

Answer 27

Striated

Short, branched cells

1-2 nuclei per cell

Central oval shaped nucleus

Cytoplasmic organelles ast at the poles of nucleus

Interconnected with neighbouring cells via intercalated discs

Question 28

What are intercollated discs?

Answer 28

Connect neighbouring discs. Consist of three intercellular junctions; Adhesion belts, desmosomes and gap junctions.

Question 29

What are adhesion belts?

Answer 29

Intercellular junction that links the contractile actin in one cell via membranous proteins to the actin in a neighbouring cell.

Question 30

What are desomosomes?

Answer 30

Intercellular junction that links the cytokeratin (cytoskeleton) to the neighboring cells cytokeratin.

Question 31

What are Gap junctions

Answer 31

Intercellular junction that fuses the cells plasma membranes together through electrochemical communication.

Question 32

What is the conduction system of the heart?

Answer 32

Specialised system that coordinates the contraction of the muscle.
Increases efficiency and contribute to the function of Av cells by telling the hert when to contract.
Autonomic nervous input to this pathway that increases/decreases heart rate.

Question 33

What is the SA node?

Answer 33

A cluster of cells where the conduction pathway begins. It spontaneously generates contraction potentials which pass through the atrial chambers through a series of pathways called the internodal branches.

Question 34

What is the AV node?

Answer 34

The gateway down into the ventricular chambers

Question 35

What do conduction pathways consist of?

Answer 35

Modified cardiac muscle cells

Question 36

What are pekingie cells?

Answer 36

Cardiac muscle cells that no longer contract and have become modified for this role carrying conduction potentials.

Question 37

Structure of pekingie cells?

Answer 37

Redundant Myofibrils that have been pushed to the periphery of the cell , centrally located nuclei, cytoplasm that is full of mitochondria and glycogen stores and gap junctions as the main intercellular junction.