Wk 4: Cardiovascular System

Question 1

5 functions of cardiovascular system

Answer 1

1. Maintains continuous movement of all body fluids
2. Transports O2 & nutrients into tissues
3. Transports CO2 & metabolic waste out of tissues
4. Temp regulation
5. Distribution of molecules: hormones & cells of immune system - e.g: secretions of pituitary gland into bloodstream

Question 2

What are the 3 tunics (3 coats) of the blood vessels

Answer 2

1. Tunica Adventitia (externa) - outer
2. Tunica Media - middle
3. Tunica Intima - inner

Question 3

What are the tiny vessels supplying the tunica externa & tunica media

Answer 3

Vaso vasora

Question 4

Describe the Tunica Externa

Answer 4

Outer supporting tissue layer

Question 5

Describe the Tunica Media

Answer 5

Intermediate muscular layer

Question 6

Describe the Tunica Intima

Answer 6

Inner lining of epithelial cells, basement membrane & collagenous tissue

Question 7

Where is the pericardial membrane positioned

Answer 7

It surrounds the heart

Question 8

What are the 3 layers of the pericardium & which of these 3 is shared with the heart wall

Answer 8

3 layers:
1. Fibrous pericardium
2. Parietal layer of serous pericardium
3. Visceral layer of serous pericardium (epicardium)
* The visceral layer of the serous pericardium (epicardium) is the layer shared with the heart wall

Question 9

What is the fibrous pericardium composed of & what does this mean for the function

Answer 9

• Composed of collagen bundles
• Due to lack of elastin in composition, this layer doesn’t change shape/size which prevents overfilling w blood

Question 10

Function of fibrous pericardium (2)

Answer 10

• Tough
• Anchors heart to diaphragm & vessels

Question 11

What does the serous pericardium produce

Answer 11

Serous fluid

Question 12

What is the positioning of the parietal pericardium

Answer 12

It is fused to the fibrous pericardium. It encases the heart like a sac

Question 13

What is the innermost layer of the pericardium

Answer 13

The visceral pericardium/epicardium

Question 14

Where is the pericardial cavity positioned

Answer 14

Between the parietal & visceral layers of the serous pericardium

Question 15

Function of pericardial cavity

Answer 15

Contains a layer of serous/pericardial fluid which acts as a lubricant, decreasing friction as heart moves

Question 15

What is cardiac tamponade

Answer 15

• Excess fluid build up in the pericardial space
• More fluid accumulates w each contraction
• Puts pressure on heart, prevents full relaxation, heart contains less blood at beginning of each heart cycle, death

Question 15

What are the 3 layers of the wall of the heart

Answer 15

1. Epicardium (tunica adventitia) - outer, shared w pericardium
2. Myocardium (tunica media)
3. Endocardium (tunica intima) - inner

Question 16

Which layer of the heart wall contains the cardiac muscle tissue

Answer 16

The myocardium

Question 17

What is endocardium composed of

Answer 17

• Special squamous epithelium called endothelium
• Elastic fibres
• Collagen fibres

Question 18

What is myocardium responsible for (1)

Answer 18

Beating of the heart

Question 19

Describe the blood flow through the pulmonary circuit

Answer 19

• Blood flows from the right side of the heart (deoxygenated)
• Blood flows to the lungs to become oxygenated
• Blood flows to the heart

Question 20

Describe the blood flow through the systemic circuit

Answer 20

• Blood flows from the left side of the heart (oxygenated)
• Blood flows to the head & rest of body
• Blood flows back to the right side of the heart (deoxygenated)

Question 21

Why do arteries have smaller lumens than veins

Answer 21

To maintain the pressure of blood flow

Question 22

What are the 3 layers of both arteries & veins

Answer 22

1. Tunica externa - outer
2. Tunica media - middle
3. Tunica intima - inner

Question 23

Main characteristic of elastic arteries

Answer 23

40-70 fenestrated elastic membranes in tunica media (need for artery wall to be able to stretch)

Question 24

Main characteristic of muscular arteries

Answer 24

• Thick tunica media composed mostly of smooth muscle (up to 40 layers)
• Mostly smooth muscle = highly contractile

Question 25

What are capillaries composed of

Answer 25

Endothelial cells

Question 26

What are continuous capillaries

Answer 26

Capillaries that have no pores or fenestrae in their walls

Question 27

What are fenestrated capillaries

Answer 27

Capillaries with pores in their walls that are covered by pore diaphragms

Question 28

Where are fenestrated capillaries found (3)

Answer 28

1. GI muscosa
2. Endocrine glands
3. Renal glomeruli

Question 29

Why do veins have valves

Answer 29

Veins part of low pressure circulation so need valves to prevent backflow of blood

Question 30

What are the walls & lumens of veins like compared to the walls & lumens of arteries

Answer 30

Veins have thinner walls and larger lumens than arteries

Question 31

Main difference in structure between arteries & veins

Answer 31

The tunica media!!
* Tunica media of arteries are thick, mainly smooth muscle cells & elastic fibres
* Tunica media of veins are thin, mainly smooth muscle cells & collagen fibres (dont need to stretch much as in low pressure circulation)