Cardiovascular system- The heart

Question 1

What does the right side of the heart do?

Answer 1

1. Receives oxygen-poor blood from tissues
2. Pumps blood to lungs to get rid of CO2 and pick up O2 via the PULMONARY CIRCUIT

Question 2

What does the left side of the heart do?

Answer 2

1. Received oxygenated blood from the lungs
2. Pumps blood to body tissues via SYSTEMIC CIRCUIT

Question 3

What does the right atrium (receiving chamber)do?

Answer 3

Receives blood returning from systemic circuit

Question 4

What does the left atrium (receiving chamber) do?

Answer 4

Receives blood returning from pulmonary circuit

Question 5

What does the right ventricle (pumping chamber) do?

Answer 5

Pumps blood through pulmonary circuit

Question 6

What does the left ventricle (pumping chamber) do?

Answer 6

Pumps blood through systemic circuit

Question 7

What happens on capillary beds (both in lungs and body tissues ?

Answer 7

Gas exchange

Question 8

What is the pericardium ?

Answer 8

A double-walled sac that surrounds the heart (made up of two layers)

Question 9

What are the two layers of the pericardium?

Answer 9

1. Superficial fibrous pericardium
2. Serous pericardium

Question 10

What does the superficial fibrous pericardium do? (3)

Answer 10

1. Functions to protect
2. Anchor heart to surrounding structures
3. Prevents overfilling

Question 11

What are the two layers of the serous pericardium and where are they found?

Answer 11

1. Parietal layer lines internal surface of fibrous pericardium
2. Visceral layer (epicardium) on external surface of heart

Question 12

What are the deep two-layered serous pericardium separated by?

Answer 12

Fluid-filled pericardial cavity (decreases friction)

Question 13

What are the three layers of the heart wall?

Answer 13

1. Epicardium
2. Myocardium
3. Endocardium

Question 14

What is the epicardium?

Answer 14

The visceral layer of serous pericardium

Question 15

What is the myocardium?

Answer 15

Circular/spiral bundles of contractile cardiac muscle cells

Question 16

What is the endocardium?

Answer 16

The innermost layer, is continuous with endothelial lining of blood vessels which lines the heart chambers.

Question 17

What are the classifications of the four chambers in the heart?

Answer 17

Two superior atria, two inferior ventricles.

Question 18

What separates the two atria?

Answer 18

The Interatrial septum

Question 19

What separates the two ventricles?

Answer 19

Interventricular septum

Question 20

Pathway of blood through the heart

Answer 20

SVC/IVC —> Coronary sinus —> Right atrium —> TRICUSPID VALVE —> Right ventricle —>PULMONARRY SEMILUNAR VALVE —> Pulmonary trunk —> 2 Pulmonary arteries —> lungs —> 4 Pulmonary veins —> Left atrium —> MITRAL VALVE —> Left ventricle —> AORTIC SEMILUNAR VALVE —> The body tissues.

Question 21

What is Angina pectoris ?

Answer 21

Thoracic pain caused by fleeting deficiency in blood delivery to myocardium

Question 22

What is myocarrdial infraction (heart attack)?

Answer 22

• Prolonged (sec - min) coronary blockage
• Areas of cell death are repaired with noncontractile scar tissue

Question 23

Describe the structure of Cardiac muscle cells

Answer 23

• Striated
• Short
• Branched
• Interconnected
• One central nucleus
• Contains numerous large mitochondria (25 - 35 % of cell volume ) that afford resistance to fatigue

Question 24

What are intercalated discs?

Answer 24

Connecting junctions between cardiac cells that contain Desmosomes and Gap junctions

Question 25

What do Desmosomes do?

Answer 25

Hold cells together, prevent cells from separating during contraction

Question 26

What do gap junctions do?

Answer 26

Allow ions to pass from cell to cell; electrically couple adjacent cells

Question 27

What are the steps for muscle contraction ? (8)

Answer 27

1- Current spreads through gap junctions to contractile cell 2- APs travel along plasma membrane and T tubules 3- Ca2+ channels open in plasma membrane and SR (sarcoplasmic reticulum) 4- Ca2+ induces Ca2+ release from SR. 5- Ca2+ binds to tryponin, exposing myosin-binding sites 6- Crossbridge cycle begins (muscle fiber contracts) 7- Ca2+ is actively transported back into the SR and ECF (extracellular fluid) 8- Tropomyosin blocks myosin-binding sites (muscle fiber relaxes)