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Flashcards in Circulatory system Deck (45):
1

What are the two related systems of the circulatory system

The cardiovascular system and lymphatic vascular system

2

What does the cardiovascular system consist of

Heart, arteries, capillaries and veins

3

Roles of the cardiovascular system

-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

4

Where is the blood within the body found

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

5

What are the 3 laters to a blood vessel

Tunica intimate, tunic media and tunica adventita

6

Tunica intimate

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

7

Tunica media

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

8

Tunica adventita

- Outer layer
- Made of supporting connective tissue

9

What separates the tunica intimate from the tunica media

Internal elastic membrane

10

What is separates the tunica media from the tunica adventita

External elastic membrane

11

What are the largest arteries termed and why

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

12

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

Vasa vasorum

13

Arterioles

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

14

Composition of capillaries

- Composed of endothelial cells and basal lamina
- Have pericytes at intervals outside basal lamina

15

Pericytes

Connective tissue cells that have contractile properties

16

Different types of capillaries

Continuous, fenestrated and sinusoidal/discontinuous

17

Continuous capillaries

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

18

Fenestrated capillaries

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

19

Sinusoidal/discontinued capillaries

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

20

What do capillaries form

Networks

21

What are microvascular networks made up of

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

22

What helps control the flow through the capillary network

Precapillary sphincters

23

Veins

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

24

Three layers of the heart

Endocardium, myocardium and epicardium

25

Endocardium

- 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

26

Myocardium

- 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

27

Epicardium

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

28

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

Coronary vessels

29

What are the two parts of the pericardium

Fibrous pericardium and serous pericardium

30

Fibrous pericardium

Is a sac of tough fibrocollagenous connective tissue

31

Serous pericardium

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

32

What is between the fibrous and serous pericardiums

Pericardial cavity

33

What is contained within the pericardial cavity

Pericardial fluid

34

What is the action of pericardial fluid

To provide lubrication for the heart

35

What is the fibrous skeleton of the heart made of

Fibrous connective tissue

36

Functions of fibrous skeleton of the heart

- Support the valves
- Provides attachment for cardiac muscle fibres

37

Heart valves

- 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

38

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

Lamina fibrosa

39

What are the 3 types of cardiac muscle cells

Contractile cells, pacemaker cells and conducting cells

40

Pacemaker cells

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

41

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

the AV node

42

From the AV node where do electrical impulses travel

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

43

What electrically isolates the atria from the ventricles

The fibrous skeleton

44

Purkinje fibres

- 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

45

In which way does excitation pass through the ventricles

Inferiorly to superiorly