Lecture 5: Anatomy of the Heart Part 2

Question 1

• label the diagram
• what phase is the heart in? how can you tell?

Answer 1

the heart is in systole.
Diagram shows the AV valve is closed and the semilunar valve is open.
This means the ventricle is contracting so blood is flowing through to the outflow artery and the AV valve is closed to prevent backflow into the atrium

Question 2

Answer 2

Question 3

what type of muscle is this? what are the features?

Answer 3

here we see cardiac muscle (brown) with red blood cells (orange) travelling through capillaries

Question 4

what phase is the left and right diagram in? how can you tell?

Answer 4

the left diagram is is diastole because it shows that the atrioventricular valves are open meaning the ventricle can fill with blood, while the semilunar valve is closed to keep blood in the ventricle

the right diagram is in systole because it shows the atrioventricular valve is closed to prevent backflow of blood into the atria while the ventricle empties into the outflow artery

Question 5

Answer 5

intercalated discs have gap junctions, adhesion belts and desmosomes between cardiac cells

Question 6

label the diagram and state the function of each artery/vein

Answer 6

• The right coronary artery supplies blood to the right ventricle, the right atrium, and the SA and AV nodes. it runs in a groove within the epicardium between the right atrium and ventricle
• The left coronary artery supplies blood to the left atrium and left ventricule. it runs a short distance and then splits into the circumflex artery which supplies the outer side and back side of the heart and the anterior interventricular artery which supplies the interventricular septum and bundle branches
• The small cardiac vein drains the right atrium and right ventricle and the great cardiac veins drains the left atrium and left atrium. Both of them meet at the coronary sinus at the posterior of the heart

Question 7

Answer 7

Question 8

what is the difference/similarities between these muscles/cells?

Answer 8

• cardiac muscle is striated like skeletal muscle
• the cells of cardiac muscle and short and branches
• cardiac muscle has 1-2 nuclei
• nucleus in cardiac muscle is centrally positioned and oval shaped
• the organelles are packed at the poles of the nucleus
• cardiac muscle is the only muscle with intercalated discs
• cardiac muscle is 20% mitrochondra
• ## the sarcomeres in cardiac muscle is irregular and branched (skeletal is linear)

Question 9

explain the different types of intercalated disc found in cardiac muscle and their function/location

Answer 9

A - adhesion belts link actin to actin via transmembrane proteins and are found in the vertical portion to transfer force between cells

B - Desmosomes link cytokeratin to cytokeratin

C - Gap junctions are involved in electrocommunication and are plased parallel (horizontal) to the force of the contraction because they are delicate junctions

Question 10

what state is the heart in these diagrams? how can you tell?

Answer 10

the top diagram is in diastole as the AV vales are open meaning the ventricles can fill with blood and the semilunar valves are closed meaning the blood will stay in the ventricle

the bottom diagram shows systole as the AV valves are closed to blood can’t backflow into the atria while the semilunar valves are open so the blood can eject from the ventricle to the outflow artery

Question 11

Answer 11