Histology

Question 1

Name four roles of the CVS

Answer 1

• transport oxygen & nutrients to tissues
• transport CO2 & other metabolic waste form tissues
• temperature regulation
• hormone & immune cell distribution

Question 2

Where can the majority of blood be found?

Answer 2

The peripheral veins

Question 3

Describe the inner layer of a blood vessel

Answer 3

tunica intima - single layer of endothelial cells supported by a basal lamina and thin connective tissue

Question 4

Describe the middle layer of a blood vessel

Answer 4

tunica media - smooth muscle

Question 5

Describe the outer layer of a blood vessel

Answer 5

tunica adventitia - connective tissue

Question 6

What separates each of the layers?

Answer 6

internal elastic membrane separates the intima and media

external elastic membrane separates the media and adventitia

Question 7

State the name given to the largest arteries

Answer 7

elastic arteries

Question 8

What is the problem in large vessels regarding blood supply?

Answer 8

Nutrients can only be obtained by the inner part so they have their own blood supply - vasa vasorum

Question 9

Describe the structure of arterioles

Answer 9

only have 1/2 layers of smooth muscle and almost no tunica adventitia

Question 10

Describe the structure of capillaries

Answer 10

composed of endothelial cells & a basal lamina they often have pericytes - connective tissue that has contractile properties

Question 11

State the three types of capillary and where they can be found

Answer 11

continuous (muscle, skin, lungs, nerves)
fenestrated (pores - gut, endocrine glands, glomeruli of kidneys)
sinusoidal/discontinuous (no basal lamina & large gaps for macromolecules - liver, spleen, bone marrow)

Question 12

How do small arterioles connect to post capillary venues?

Answer 12

Through a network of;

• metaarterioles
• thoroughfare channels
• capillaries
• pre capillary sphincters (help to control flow)

Question 13

Describe the structure of a post capillary venule

Answer 13

endothelial lined cell, thin layer of connective tissue & occasional pericyte - important site for exchange

Question 14

when do capillaries become venules?

Answer 14

when they acquire smooth muscle

Question 15

Describe the structure of veins

Answer 15

thin but continuous tunica media, large veins have thick tunica adventitia with bundles of smooth muscle

Question 16

What ensures blood flow in veins?

Answer 16

Valves, inward extensions of the tunica intima

Question 17

State the three layers of the heart

Answer 17

endocardium
myocardium
epicardium
All within the pericardial sac

Question 18

What does the endocardium consist of?

Answer 18

• endothelium
• basal lamina
• thin layer of collagen fibres
• layer of denser connective tissue

Question 19

What can be found in some areas of endocardium?

Answer 19

subendocardium - loose connective tissue containing small blood vessels & nerves

Question 20

What does the myocardium consist of?

Answer 20

• bundles & layers of contractile cardiac muscle
• muscle fibres surrounded by collagen connection tissue
• connective tissue has a rich network of capillaries

Question 21

Describe cardiac muscle cells

Answer 21

they have a single nucleus & intercalated discs passing across the fibres at irregular intervals, they attach to cells and allow spread of electrical activity

Question 22

What does the epicardium consist of?

Answer 22

• single layer of mesothelium
• basal lamina
• fibroelastic connective tissue & adipose

Question 23

Name the two layers of pericardium

Answer 23

Fibrous - tough fibrocollagenous connective tissue sac

Serous - mesothelium backed with basal lamina & connective tissue

Question 24

What are the two types of serous pericardium?

Answer 24

Parietal - inner surface of the fibrous pericardium

Visceral - covers the surface of the heart

Question 25

What does the pericardial fluid do?

Answer 25

lubricates heart movement

Question 26

Describe the fibrous skeleton

Answer 26

thick bands of connective tissue supports the valves & provide attachment for muscle fibres

Question 27

Describe the structure of the heart valves

Answer 27

outer layer of endothelium with a basal lamina, layers of collagen, elastic fibres & a core of dense connective tissue - lamina fibrosa

Question 28

Name the type of valve that separates the atria and ventricles

Answer 28

leaflet valves - anchored by papillary muscles in the wall of the ventricle by collagenous strands

Question 29

What do you call the collagenous strands connecting the valve to the atria?

Answer 29

chordea tendineae

Question 30

Name the three types of cardiac muscle cell

Answer 30

• contractile
• pacemaker
• conducting

Question 31

Describe the pacemaker/conducting cells

Answer 31

• pale, few myofibrils
• little glycogen
• no T-tubule system

Question 32

Describe the purkinje fibres

Answer 32

larger than normal cardiac muscle cells found in the subendocardial layer

• abundant glycogen
• no T-tubule
• no intercalated discs
• sparse actin & myosin

Question 33

What is the role of the lymphatic system?

Answer 33

Drains tissue fluid, eventually returning it to the veins in the base of the neck

Question 34

What does interstitial fluid contain?

Answer 34

Ions, lipids, proteins & sometimes cells

Question 35

State the role of lymph nodes

Answer 35

Provide immunological surveillance & have valves, smooth muscle & pressure to produce flow