Histology 4 (Blood Vessels And Nerves)

Question 1

What is the lumen?

Answer 1

The channel where blood flows

Question 2

What is the lumen bounded by?

Answer 2

A layer of squamous endothelial cells which rest on a basement membrane

Question 3

What surrounds the squamous endothelium in the lumen?

Answer 3

A thin layer of loose connective tissue called the intimate

Question 4

What is the intima bound by?

Answer 4

A layer of elastic tissue called the internal elastic lamina

Question 5

What is around the lamina in the lumen?

Answer 5

Media

A thick layer of connective tissue generally comprising smooth muscle with some fibroblasts and variable amounts of collagen and elastin

Question 6

What surrounds the media in the lumen

Answer 6

External elastic lamina

Layer of elastic tissue

Question 7

What surrounds the external elastic lamina?

Answer 7

Adventitia

Loose connective tissue

Question 8

What are the elastic arteries?

Answer 8

Large arteries near the heart:
Aorta and Pulmonary arteries

Question 9

What is the structure of elastic arteries?

Answer 9

Layer of vascular endothelial cells resting on a basement membrane

Loose fibrous connective tissue called intima

Internal elastic Lamina

Media (Abundant concentric sheets of elastin)

External elastic lamina

Adventitia (loose fibrous connective tissue)

Question 10

What are the most abundant arteries in the body?

Answer 10

Muscular arteries

Question 11

What is the structure of the muscular arteries?

Answer 11

Lumen

Intima lined on it’s inner surface by vascular endothelial cells resting on a basement membrane

Intima of loose fibrous connective tissue

A muscular media comprising concentric layers of smooth muscle

The media is bounded by an internal and external elastic lamina

Sheets of elastin still found in media

Entire vessel is surrounded by a layer of loose connective tissue, the Adventitia

Question 12

Give examples of muscular arteries

Answer 12

Radial artery at the wrist

Splenic artery

Question 13

What are arterioles?

Answer 13

Resistance vessels of the circulation

Question 14

What is the difference between a muscular artery and arteriole?

Answer 14

Arbitrary

Defined as having 3 or fewer muscle layers in their media
Or artery less than 100 microns in diameter

Question 15

Can elastic laminae in arterioles be seen?

Answer 15

No elastic laminae are generally poorly defined

Question 16

What are the differences in structure between capillaries and arteries?

Answer 16

Capillaries don’t have an adventitia, external elastic lamina, media, internal elastic lamina or intima

Question 17

What is the structure of a capillary?

Answer 17

Layer of vascular endothelial cells resting on the inside of a basement membrane

Question 18

How is the size of capillaries regulated?

Answer 18

Need to be able to constrict or relax these vascular channels

This is achieved by a layer of cells present on the outside of capillaries called pericytes

Question 19

What do pericytes do on the smallest capillaries?

Answer 19

Form a discontinuous layer on the outside of the capillary which becomes continuous as the capillaries get larger

Question 20

What happens when the vascular endothelium is incomplete in some capillaries?

Answer 20

Forms windows that facilitates the movement of materials out of the circulation and into the surrounding tissues, these are the fenestrated capillaries

Question 21

What are capillaries made of?

Answer 21

Composed entirely of thin-walled endothelial cells with no surrounding muscle or connective tissue

Question 22

What is meant as ‘closed’ capillaries?

Answer 22

The layer of vascular endothelial cells is complete

Question 23

What does it mean if the endothelial layer is incomplete?

Answer 23

Creates leaky fenestrated capillaries

Question 24

Give examples of tissues with fenestrated capillaries?

Answer 24

Kidney and liver

Question 25

Where do capillaries drain into?

Answer 25

Venous system

Question 26

What does the venous system begin with?

Answer 26

Venules

Question 27

What is the difference in structure between arteries and veins?

Answer 27

Veins have no elastic lamina Arteries and arterioles have a thicker muscular wall and smaller lumen

Question 28

What are venules typically associated with?

Answer 28

Arterioles

Question 29

Do venules have thick or thin walls?

Answer 29

Thin walled vessels

Question 30

What do pericytes do to venules?

Answer 30

Contractile pericytes wrap around outside of endothelial cells and form a complete layer as venules get larger.

Question 31

What are pericytes replaced with when venules become veins?

Answer 31

Smooth muscle Muscular smooth muscle media

Question 32

What happens to the media in larger veins?

Answer 32

The media becomes thicker Still thinner than in arteries

Question 33

Describe the structure of smooth muscle in large veins

Answer 33

May be arranged circumferentially around the vein Longitudinal orientation

Question 34

Describe the structure of lymphatics?

Answer 34

Thin walled vessels Have valves

Question 35

What is the pink material in a histogram or lymphatics?

Answer 35

Lymph DO NOT CONTAIN BLOOD

Question 36

What is lymph?

Answer 36

Form of fluid derived from blood plasma

Question 37

Are blood cells found within lymphatics?

Answer 37

Red blood cells not found Lymphocytes may be found

Question 38

What is the main way that lymphocytes travel around the body?

Answer 38

Circulate in the blood

Question 39

What does the lumen in lymphatics contain?

Answer 39

Amorphous eosinophilic protein rich lymph with scattered lymphocytes

Question 40

What is the lumen in lymphatics lined with?

Answer 40

Lined with a layer of vascular endothelium Thin intima and media Thin Adventitia

Question 41

What is the structure of peripheral nerves?

Answer 41

Composed of nerves cells which have a cell body typically located in the ganglion and a long axon

Question 42

What does the axons do in the peripheral nerves?

Answer 42

Form the bulk of the peripheral nerve Supported by Schwann cells

Question 43

What do most peripheral nerves comprise of?

Answer 43

Myelinated axons

Question 44

What does the myelin do?

Answer 44

Acts as an insulating sheath

Question 45

What is the myelin produced by?

Answer 45

Schwann cells

Question 46

What is the function of the connective tissue in peripheral nerves?

Answer 46

Binds individual axons together, performs fascicles, and which binds fascicles together to form nerve fibres

Question 47

What do axons look like on a histogram?

Answer 47

White circles surrounded by thin brown lines

Question 48

What are the thin brown circles on a histogram?

Answer 48

Myelin sheaths

Question 49

Why are nerves considered alongside blood vessels?

Answer 49

Commonly found together as a cardiovascular bundle

Question 50

What stain is used for myelin?

Answer 50

Silver stain Does not stain readily with H&E

Question 51

What is the gap between Schwann cells called?

Answer 51

Nodes of Ranvier

Question 52

What do Schwann cells do?

Answer 52

Envelops and spirals around the axons Support one or more axons and produce myelin in some cases

Question 53

What type of axons are larger and transmit impulses faster?

Answer 53

Myelinated Axons

Question 54

With what type of microscope can neurosecretory granules be seen?

Answer 54

Electron microscope

Question 55

Where are neurochemicals released from?

Answer 55

Presynaptic bulb

Question 56

Where do sensory neurons have their cells bodies?

Answer 56

Dorsal root ganglia

Question 57

Where do sympathetic and parasympathetic neurones have their cell body?

Answer 57

Ganglia and in the brain and local ganglia of all organs

Question 58

What types of cytoskeleton fibre are contained in neurons?

Answer 58

Microtubules and neurofilaments

Question 59

What is the myelin mainly composed of?

Answer 59

Phospholipid bilayer with proteins inserted. Sphinogomyelin is the predominant phospholipid