Cardiology - Histology

Question 1

What are the three layers of all blood vessels apart from the capillaries?

Answer 1

Tunica adventitia/ externa
Tunica media
Tunica intima

Question 2

What makes up the tunica adventitia?

Answer 2

Simple squamous epithelium - connective tissue

Question 3

Why does the tunica adventitia need its own blood sypply and what supplies it?

Answer 3

This layer needs its own blood supply because it is quite thick.

The blood vessels that supply the tunica adventitia are called vasa vasorum (vessels of the vessels).

Question 4

What makes up the tunica media?

Answer 4

Thick section and is made up of smooth muscle

Question 5

What makes up the tunica intima?

Answer 5

Endothelium

Question 6

What three layers make up the heart wall?

Answer 6

Endocardium
Myocardium
Epicardium

Question 7

Where can the endocardium be found?

Answer 7

Lines heart chambers

Question 8

What is the endocardium made of?

Answer 8

Simple squamous epithelium sitting on a basement membrane

Question 9

What does the endocardium form?

Answer 9

Valves

Question 10

What is the myocardium?

Answer 10

Thick middle layer of heart wall

Question 11

What does the myocardium consist of?

Answer 11

Cardiomyocytes with its branching and intercalated discs and a central nucleus

Question 12

How are myocytes connected?

Answer 12

Intercalated discs

Question 13

Why does the myocardium contain a rich capillary bed?

Answer 13

Because its very energetic

Question 14

What is the epicardium?

Answer 14

Outer layer of heart wall

Question 15

What makes up the epicardiun?

Answer 15

Simple squamous membrane + basement membrane + connective tissue

Question 16

What is the epicardium the same as?

Answer 16

The visceral layer of the serous pericardium and the epicardium are the SAME layer

Question 17

What branches does the epicardium contain?

Answer 17

Main branches of coronary arteries

Question 18

What are the differences between veins and arteries?

Answer 18

A:

• Thick tunica media
• Smaller, rounded
• Thin tunica adventitia

V:

• Thin tunica media
• Larger, flatter
• Thick adventitia
• Valves to prevent back flow = endothelial projections into lumen

Question 19

What are the types of arteries?

Answer 19

Elastic
Muscular
Arterioles

Question 20

What are examples of elastic arteires?

Answer 20

Large conducting - eg aorta, common carotid, pulmonary

Question 21

What are examples of muscular arteries?

Answer 21

Distributing arteries - coronary, radial, femoral

Question 22

What are examples of arterioles?

Answer 22

Terminal branches which supply blood to capillary bed

Question 23

Why does the aorta need a lot of elastic fibres?

Answer 23

Stretches during systole
Relaxes during diastole

Recoil and stretchability is due to presence of extensive amounts of elastic fibres in T. Media

Question 24

What does the tunica media of muscular arteries have?

Answer 24

Smooth muscle cell
No elastic laminae

Question 25

How are elastic fibres in muscular arteries concentrated?

Answer 25

In between 2 defined sheets called the internal elastic laminae (IEL) and the external elastic lamina (OEL)

Question 26

Where can the internal elastic laminae be found?

Answer 26

Just under the epithelium

Question 27

Where can the external/outer elastic lamina be found?

Answer 27

Between tunica media and tunica adventitia

Question 28

What are arterioles?

Answer 28

Smaller muscular arteries that gradually change to become arterioles

Question 29

How many layers of smooth muscle are in the tunica media of arterioles?

Answer 29

1-2

Question 30

What do arterioles lack?

Answer 30

Tunica adventitia InEL EEL

Question 31

What are features of arterioles?

Answer 31

Rich sympathetic nerve innervation Control blood flow to capillary beds (local) Control blood pressure (systemic)

Question 32

What are capillaries used for?

Answer 32

Main exchange site for nutrients and gases and therefore have a very thin tunica intima and low blood pressure

Question 33

What are pericytes?

Answer 33

Incomplete layer of cells surrounding capillary - have contracile properties which control blood flow

Question 34

What layers does a capillary lack?

Answer 34

Tunica media Tunica adventitia

Question 35

What are the three types of capillary?

Answer 35

Continuous - no gaps Fenestrated - have gaps Discontinuous/sinusoids - have wide caps

Question 36

Features of continuous capillary

Answer 36

Control what is exchanged Material must pass through cell or between cell Selective transport mechanism eg in muscle

Question 37

Features of fenestrated capillary

Answer 37

Have pores Diaphragms filters molecules by MW &/ or charge Eg endocrine glands, kidney renal corpuscle

Question 38

Features of continuous capillary

Answer 38

Gaps between endothelial cells and basement membranes Allow free passage of fluid and cells Eg liver, spleen, bone marrow

Question 39

What are arteriovenous (AV) shunts used for?

Answer 39

Bypass capillary beds Eg - in skin for thermoregulation

Question 40

What is the structure of a vein?

Answer 40

Tunica adventitia/ externa - thin Tunica media - thin Tunica intima - thin

Question 41

What are the valves of veins?

Answer 41

Folds of tunica intima

Question 42

Difference between superficial and deep veins

Answer 42

Superficial - thick wall - no surrounding support Deep - thin walled - surrounded by support and deep fascia and muscles - superficial veins drain into deep veins - DVT

Question 43

Purpose of lymphatic system

Answer 43

Drains tissue fluid lost from blood capillaries Drains into the systemic venous system

Question 44

Where are nodes of the lymphatic system?

Answer 44

Alongside major veins and around origins of major arteries

Question 45

Features of lymph capillaries

Answer 45

Blind end capillaries Lined by very thin endothelium No RBC in lumen

Question 46

What are anchoring filaments in lymph capillaries?

Answer 46

Fine collagenous filaments link endothelial cell to surrounding tissue keeping lumen open