Circulatory system

Question 1

What are the two related systems of the circulatory system

Answer 1

The cardiovascular system and lymphatic vascular system

Question 2

What does the cardiovascular system consist of

Answer 2

Heart, arteries, capillaries and veins

Question 3

Roles of the cardiovascular system

Answer 3

• Transport oxygen and nutrients to the tissue
• Transport CO2 and other metabolic waste from the tissue
• Temperature regulation
• Distribution of hormones and immune cells
• Penile erection

Question 4

Where is the blood within the body found

Answer 4

65% in peripheral veins, 20% in heart and lungs, 10% in peripheral arteries and 5% in capillaries

Question 5

What are the 3 laters to a blood vessel

Answer 5

Tunica intimate, tunic media and tunica adventita

Question 6

Tunica intimate

Answer 6

• Inner layer
• Single layer of squamous epithelial cells termed endothelial cells
• Supported by a basal lamina and a thin layer of connective tissue

Question 7

Tunica media

Answer 7

• Middle layer
• Made up predominantly of smooth muscle
• Thickness of this layer varies

Question 8

Tunica adventita

Answer 8

• Outer layer

- Made of supporting connective tissue

Question 9

What separates the tunica intimate from the tunica media

Answer 9

Internal elastic membrane

Question 10

What is separates the tunica media from the tunica adventita

Answer 10

External elastic membrane

Question 11

What are the largest arteries termed and why

Answer 11

Elastic arteries because they have many sheets of elastic fibres in their tunica media to provide elastic recoil

Question 12

Some vessels need their own vascular supply and this is known as the

Answer 12

Vasa vasorum

Question 13

Arterioles

Answer 13

• Only have one or two layers of smooth muscle in their tunica media
• Almost no adventita
• Important in controlling blood flow

Question 14

Composition of capillaries

Answer 14

• Composed of endothelial cells and basal lamina

- Have pericytes at intervals outside basal lamina

Question 15

Pericytes

Answer 15

Connective tissue cells that have contractile properties

Question 16

Different types of capillaries

Answer 16

Continuous, fenestrated and sinusoidal/discontinuous

Question 17

Continuous capillaries

Answer 17

• Most common

- Found in muscle, connective tissue, lung, skin and nerves

Question 18

Fenestrated capillaries

Answer 18

• Have pores in the walls

- Found in the mucosa of the gut, endocrine glands, and the glomeruli of the kidney

Question 19

Sinusoidal/discontinued capillaries

Answer 19

• Lack a basal lamina
• Have large gaps through which macromolecules and cells can pass through
• Found in liver, spleen and bone marrow

Question 20

What do capillaries form

Answer 20

Networks

Question 21

What are microvascular networks made up of

Answer 21

Small arterioles connecting to a postcapillary venule, through a network of met arterioles, thoroughfare channels, and capillaries

Question 22

What helps control the flow through the capillary network

Answer 22

Precapillary sphincters

Question 23

Veins

Answer 23

• Relatively thin but continuous tunica media
• Have a thick tunica adventitia
• Flexible and can accommodate expansion

Question 24

Three layers of the heart

Answer 24

Endocardium, myocardium and epicardium

Question 25

Endocardium

Answer 25

- Lines the entire inner surface of the heart - Composed of endothelium, basal lamina, a thin layer of collagen fibres, and a layer of dense connective tissue - In some areas there is subendocardium of loose connective tissue containing small blood vessels and nerve and the branches of the the impulse connecting system

Question 26

Myocardium

Answer 26

- Thick middle layer - Bundles and layers of contractile cardiac muscle fibres - Individual fibres are surrounded by delicate, collagenous connective tissue with a rich network of capillaries

Question 27

Epicardium

Answer 27

- Outer layer of the heart - A single layer of flattened epithelium called mesothelium - Basal lamina - Fribroelatsic connective tissue and in spaces adipose tissue

Question 28

What is embedded within the adipose tissue on the surface of the heart

Answer 28

Coronary vessels

Question 29

What are the two parts of the pericardium

Answer 29

Fibrous pericardium and serous pericardium

Question 30

Fibrous pericardium

Answer 30

Is a sac of tough fibrocollagenous connective tissue

Question 31

Serous pericardium

Answer 31

Made up of a layer of simple squamous epithelium, backed by a basal lamina and connective tissue

Question 32

What is between the fibrous and serous pericardiums

Answer 32

Pericardial cavity

Question 33

What is contained within the pericardial cavity

Answer 33

Pericardial fluid

Question 34

What is the action of pericardial fluid

Answer 34

To provide lubrication for the heart

Question 35

What is the fibrous skeleton of the heart made of

Answer 35

Fibrous connective tissue

Question 36

Functions of fibrous skeleton of the heart

Answer 36

- Support the valves | - Provides attachment for cardiac muscle fibres

Question 37

Heart valves

Answer 37

- Outer endothelial layer with a basal lamina - Layer of collagen and elastin fibres - A core of dense connective tissue - Anchored to papillary muscles in the wall of the ventricle by chordae tendinae - No blood vessels

Question 38

What is the core of dense connective tissue in the heart valves known as

Answer 38

Lamina fibrosa

Question 39

What are the 3 types of cardiac muscle cells

Answer 39

Contractile cells, pacemaker cells and conducting cells

Question 40

Pacemaker cells

Answer 40

- Highly specialised muscle cells - Embedded in an extensive matrix of connective tissue - Have few myofibrils, little glycogen and no proper T-tubule system

Question 41

At the junction of the atria and vntricles, what picks up the depolarisation

Answer 41

the AV node

Question 42

From the AV node where do electrical impulses travel

Answer 42

Down the interventricular septum via AV bundle, then through the left and right bundle branches to the apex of heart and then they contact the Purkinje fibres

Question 43

What electrically isolates the atria from the ventricles

Answer 43

The fibrous skeleton

Question 44

Purkinje fibres

Answer 44

- Larger than normal cardiac muscle cells - Found in the sunendocaridal layer just deep to endocardium - Abundant glycogen, no T-tubules, no intercalated discs and sparse actin and myosin - Distribute excitatory activity

Question 45

In which way does excitation pass through the ventricles

Answer 45

Inferiorly to superiorly