Lecture 5 - Blood vessels

Question 1

Four layers of blood vessels:

Centre of vessels
First layer after the lumen
Second layer after the lumen
Third layer after the lumen

Answer 1

⠀
⠀
Lumen
Tunica intima
Tunica media
Tunica adventitia

Question 2

Tunica intima: what is it and what is it made of?

Answer 2

Thinnest, lined with simple squamous, sub endothelial connective tissue, basal lamina of the epithelial cells

Question 3

Tunica media: what is it made of?

Answer 3

Smooth muscle fibres in loose connective tissue

Question 4

Tunica adventitia: what does it merge with and what may it contain

Answer 4

Merges with surrounding connective tissue, may contain vasa vasorum (vessels to the vessel)

Question 5

Types of arteries

Answer 5

Elastic, muscular, arterioles

Question 6

Elastic arteries: what does it do, what diameter, adaptions, and what is an example?

Answer 6

Withstand pressure changes during the cardiac cycle and esnure continuous blood flow

Can be up to 2.5cm

Thick tunica media with many elastic fibres and few smooth muscle cells

The aorta -> brachiocephalic -> common carotid

Question 7

Muscular arteries: what do they do, diameter, adaptions, examples?

Answer 7

Vasodilates or vasoconstricts to meet the needs of the organ

0.5mm to 4mm

Lots of smooth muscle cells in tunica media, internal elastic laminae (IEL between intima and media) and external elastic laminae (EEL between media and externa), thick tunica externa

Femoral, brachial

Question 8

Arterioles: what does it do, diameter, adaptions?

Answer 8

Capable of vasoconstriction & vasodilation so involved in blood pressure control

<30 micrometers

Poorly defined adventia, only one or two layers of smooth muscle in media

Question 9

Capillaries: what do they do, what adaptions for their function, blood flow speed, diameter, three types of capillaries?

Answer 9

Found near almost every cell, connects arterioles and venules, site of 2-way gaseous and material exchange

Thin walls which allow for easier material exchange

Blood flows very slowly

Roughly 8 micrometres in diameter

Continuous, fenestrated, and sinusoidal

Question 10

Continuous capillaries: where are they found?

Answer 10

Majority are continuous and these are found in the lungs and skleletal and smooth muscle

Question 11

Fenestrated capillaries: function in the body, adaptions and what do they do?

Answer 11

Absorption in the kidney, choroid plexus, and the endocrine glands

Pores (fenestrations) allowing the exchange of water or large solutes (small polypeptides)

Question 12

Sinusoidal capillaries: function in the body, adaptions and what do they do?

Answer 12

Exchange of large solutes (plasma proteins)

Incomplete or absent BM, specialised lining cells (phagocytes in the liver engulfing damaged WBCs)

Question 13

Metarterioles

Answer 13

One supplies blood to a whole capillary bed

Constriction of a metarteriole will reduce blood flow to the bed it’s connected to

Question 14

Precapillary sphincter

Answer 14

Guards the entrance to each capillary, dilation or constriction will either increase or decrease blood flow

Question 15

Arteriovenous anastomes

Answer 15

Form direct connection between the arteriole and venule

Plays an important role in temperature regulation

Question 16

Venules: what do they do, what diameter, and what are the adaptations?

Answer 16

Connect capillary beds to veins

20 micrometers

Small endothelium on a basement membrane, large numbers of smooth muscle cells located outside the endothelium

Question 17

Veins: what do they do, diameter, and adaptation?

Answer 17

Low pressure system with a large lumen and many valves to aid blood to move back to the heart

Small (<2mm), medium (2-9mm), and large (>9mm)

Thin walled, tunica externa is predominant, valves

Question 18

Systolic

Answer 18

One of the two methods of measuring blood pressure, monitors the pressure in the arteries when the heart beats

Question 19

Diastolic

Answer 19

One of the two methods of measuring blood pressure, monitors the pressure in the arteries when the heart is resting

Question 20

Anatomical positions: superior vs inferior

Answer 20

Superior is above, inferior is below

Question 21

Anatomical positions: Medial vs lateral

Answer 21

Medial is closer to the centre point, lateral is away from the centre point

Question 22

Anatomical positions: proximal vs distal

Answer 22

Proximal is closer to the torso, distal is further away from the torso

Question 23

Anatomical positions: ventral vs dorsal

Answer 23

Ventral (anterior) means the front, dorsal (posterior) means behind

Question 24

Anatomical positions: saggital plane

Answer 24

Splits the body into right and left sections by passing the body through the front to the back

Question 25

Anatomical positions: coronal plane

Answer 25

Splits the body into front and back sections by passing the body through one side to the other

Question 26

Anatomical positions: transverse plane

Answer 26

Splits the body into upper and lower sections by passing the body through the middle of the body in a horizontal way