B1 - The heart

Question 1

What is the overall function of the cardiovascular system?

Answer 1

To transport nutrients and Oxygen rich blood to all parts of the body and to carry deoxygenated blood to the lungs.

Question 2

what does the cardiovascular system consist of?

Answer 2

Heart
Blood vessels :
- arteries
- veins
- capillaries
Blood:
- Red blood cells (RBC)
- White blood cells (WBC)
- platelets

Question 3

Myogenic heart muscle and its role in contraction:

Answer 3

-> the hearts own nerve conduction system
striated
-> resembles skeletal muscle but the fibres are narrower
-> cells are joined together at intercalated discs
-> allow swift transmission of impulses between cells

Question 4

Give the nervous control of the cardiac cycle in 8 steps:

Answer 4

1) Sinoatrial node (SAN) receives impulse from brain to start its own impulse to control cardiac cycle.

2) SAN generates a nerve impulse wave to both atria walls, they contract.

3) Collagen fibres stop wave travelling further, ventricles DO NOT contract until blood has moved into them.

4) Wave meets at junction between atria and ventricles, where Atrioventricular node (AVN) is.

5) AVN generates its own impulse down the Bundle Of His (BOH)

6) BOH breaks up into purkinje fibres

7) Purkinje fibres transmit impulse from base of the heart upwards

8) ventricles contract and blood is forced out of ventricles into aorta or pulmonary artery.

Question 5

Describe the function of the arteries:

Answer 5

To carry blood away from the heart

Question 6

Describe the structural features of the arteries:

Answer 6

-> walls made up of thick, elastic, muscle tissue
-> high blood pressure
-> medium lumen
-> no valves

Question 7

Describe the function of the Veins:

Answer 7

Carries blood to the heart

Question 8

Describe the structural features of the Veins:

Answer 8

-> Walls are made of connective tissue with smooth and endothelial muscle cells
-> low blood pressure
-> large lumen to reduce friction in walls
-> lots of valves to reduce backflow

Question 9

Why does the vein have a large lumen?

Answer 9

To reduce friction of blood flow in the wall of the veins

Question 10

why do the veins have lots of valves?

Answer 10

to prevent backflow of blood towards the heart

Question 11

Describe the function of the capillaries:

Answer 11

to allow exchange of materials between blood and cells

Question 12

describe the structural features of the capillaries:

Answer 12

-> walls are one cell thick (so thin)
-> have decreasing blood pressure
-> tiny lumen
-> no valves

Question 13

Describe the function of the arteriole:

Answer 13

-> to carry blood away from the heart, control blood flow and pressure by using muscle to change their diameter
-> decreasing blood pressure

Question 14

describe the function of the venule:

Answer 14

-> To collect deoxygenated blood and waste products, carrying them towards veins
-> low blood pressure

Question 15

Name the different blood types in the ABO system:

Answer 15

A
B
AB
O

Question 16

describe blood type A:

Answer 16

-> A antigen
-> Anti-B antibody in serum
-> donates to A, AB
-> receives from A, O

Question 17

describe blood type B:

Answer 17

-> B antigen
-> Anti-A antibody in serum
-> donates to B, AB
-> receives from B, O

Question 18

Describe blood type AB:

Answer 18

-> A and B antigens on cell surface
-> No antibodies in serum
-> donates to A, B
-> Universal recipient (Receives from all)

Question 19

Describe blood type O:

Answer 19

-> No antigens on surface
-> Anti-A and Anti-B antigens in serum
-> Universal donor
-> can only receive blood from O

Question 20

the rhesus antigen:

Answer 20

-> rhesus positive - blood cells have the antigen
-> rhesus negative - blood cells don’t have the antigen
-> Blood with RH+ agglutinates with Anti-RH serum
-> Blood with RH- wont agglutinate with anti-Rh serum

Question 21

What does agglutinate mean?

Answer 21

To stick together

Question 22

what is an Acute Haemolytic transfusion reaction (AHTR)?

Answer 22

-> Occurs when given the wrong blood
-> Symptoms:
– cold clammy skin
– low blood pressure
– nausea / vomiting
– acute kidney failure
–death

Question 23

Explain what could happen if a person was given the wrong blood type:

Answer 23

Blood agglutinates, antibodies bind the rbc’s together in clumps, resulting in AHTR, where the immune system attacks donated blood cells.

Question 24

Stages of the cardiac cycle, recap so shortened 1-4:

Answer 24

1) Atrial diastole (relaxation) - atria fill with blood, atrioventricular valves open.

2) Ventricular diastole (relaxation) - rising pressure in atria causes the AV valves to open and ventricles fill, semi-lunar valves close.

3) Atrial systole (contraction) - atria contract, forced blood into ventricles, AV valves open and semi lunar valves close.

4) Ventricular systole (contraction) - ventricles contract, increases pressure in the ventricles, forces blood into aorta and pulmonary artery, AV valves are forced shut.

Question 25

why is the circulatory system a double system?:

Answer 25

It has 2 loops, blood passes through the heart twice in a complete circulation.

Question 26

Give the name of the 2 loops and how they work:

Answer 26

-> Pulmonary circuit - carries deoxygenated blood to lungs to be oxygenated and then returns it to the heart

-> Systematic circuit - pumps oxygenated blood from the heart to other parts of the body and then carries deoxygenated blood back to the heart.

Question 27

What does the double circuit mean?

Answer 27

-> The double circuit means that blood is passing to tissues oxygenated since the two loops are separate
-> Blood is delivered to tissues under high pressure so is more efficient since it is pumped twice by the heart.

Question 28

Functioning of the heart and cardiac cycle:

Answer 28

-> contraction and relaxation of muscular heart walls creates pressure differences

-> pressure differences between chambers make blood flow from regions of high pressure to low pressure

-> systole: the walls of a chamber contracting to allow pressure of blood in that chamber to rise,

-> diastole: the walls of a chamber contracting to allow pressure of blood inside chamber to fall

-> pressure changes open and close the valves in the heart which controls the flow of blood in the heart.