The Circulatory System

Question 1

Overall, what does the circulatory system mediate?

Answer 1

The continuous movement of all body fluids

Question 2

What are the four main functions of the circulatory system?

Answer 2

1. To transport oxygen and nutrients to tissues
2. To transport co2 and metabolic waste away from tis
3. Temperature regulation
4. Distribution of molecules and cells, e.g. hormones & immunocytes

Question 3

What are the two functional components of the circulatory system?

Answer 3

1. The blood vascular system

2. The lymph vascular system

Question 4

What is the blood flow initiated by?

Answer 4

The heart obviously

Question 5

What is microcirculation?

Answer 5

Microcirculation refers to the smallest vessels in the body. The main sites of interchange between the tissues and the blood

Question 6

Who was the first known to describe the systemic system and properties of blood in detail?

Answer 6

William Harvey

Question 7

What are the three layers that the whole system has in common?

Answer 7

The tunica intima - the inner lining
The tunica media - intermediate
The tunica adventitia - outer supporting layer

Question 8

What is the tunica intima?

Answer 8

The inner lining composed of flattened epithelial cells, endothelium, supported by a basement membrane and delicate collagenous tissue

Question 9

What is the tunica media?

Answer 9

Intermediate mainly muscular layer. Shows the most variation out of all the layers

Question 10

What is the tunica adventitia?

Answer 10

The outer supporting tissue layer

Question 11

The tissues of thick walls of large vessels cannot sustain themselves by diffusion of nutrients from the lumina alone so what are they supplied by?

Answer 11

By the vasa vasorum - small arteries running in the tunica adventitia

Question 12

The vasa vasorum are small arteries running in the tunica adventitia, where do they go from here?

Answer 12

They send arterioles and capillaries into the tunica media

Question 13

The heart is made of the same three cell layers as the tissues in the

Answer 13

blood vessels

Question 14

What are the three layers in the heart - both names?

Answer 14

1. tunica intima - endocardium
2. tunica media - myocardium
3. tunica adventitia - epicardium or visceral pericardium

Question 15

What are papillary muscles?

Answer 15

A small muscle within the heart that anchors the heart valves

Question 16

Where are the purkinje fibres found, in which layer?

Answer 16

In the subendocardial layer - run immediately below the endocardium

Question 17

What is the function of the purkinje fibres?

Answer 17

To transmit electrical impulses in a co-ordinated manner

Question 18

Describe the structure of the cells making up the endocardium

Answer 18

A surface layer of flattened endothelial cells

Question 19

What is one of the functions of the endocardium?

Answer 19

Controls myocardial function

Question 20

Describe the structure of the epicardium

Answer 20

A dense sheet of fibro-collagenous and elastic tissue

Question 21

What is one of the functions of the mesothelial cells that make up the epicardium?

Answer 21

On the outer surface a single layer of flat mesothelial cells (simple squamous epithelium) are responsible for secreting lubricating fluid

Question 22

What fibres make up the mycocardium?

Answer 22

Cardiac muscle fibres

Question 23

What joins together different cardiac muscle cells?

Answer 23

Intercalated discs

Question 24

Cardiac muscles have ____ nuclei and regular cytoplasmic _______

Answer 24

central and striations

Question 25

What are purkinje fibres?

Answer 25

Modified cardiac muscle fibres involved in the regulation of co-ordinated contraction of the heart

Question 26

Where do the purkinje fibres first begin?

Answer 26

About halfway down the interventricular septum

Question 27

The heart valves consist of leaflets of…

Answer 27

fibroelastic tissue covered by endothelium on both sides

Question 28

What is the function of the arterial system?

Answer 28

To distribute blood from the heart to capillary beds throughout the body

Question 29

The cyclical pumping action of the heart ventricles produces a…

Answer 29

Pulsatile flow in the arterial system