Week 3 - Blood Vessels, Gross Circulatory System

Question 1

What are the 4 components of a blood vessel

Answer 1

Lumen
Tunica intima
Tunica media
Tunica adventitia

Question 2

Tunica intima (3)

Answer 2

Endothelium - simple squamous epithelium
Basal laminate of epithelial cells
Subendothelial connective tissue

Question 3

Tunica media (2)

Answer 3

Smooth muscle fibres in loose connective tissue
May contain elastic fibres

Question 4

Arteries vs veins

Answer 4

Arteries deal with blood under high pressure (thick walls) , whereas veins deal with blood under low pressure (thin walls)

Arteries = garden hoses
Veins = fire hoses

Question 5

Types of arteries?

Answer 5

Elastic (conducting)
Muscular (distributing)
Arterioles (resistance)

Question 6

Elastic arteries (4)

Answer 6

E.g. aorta, braciocephalic, common carotid
- diameter : up to 2.5cm
- withstand pressure changes during cardiac cycle + ensure continuous blood flow

Structural adaptations : thick tunica media w/ many elastic fibres + few smooth muscle cells

Question 7

Muscular arteries (6)

Answer 7

E.g. most named arteries e.g. femoral, brachial
- diameter: 0.5mm to 0.4 cm
- distributes blood to muscles + organs
- capable of vasodilation + vasoconstriction to control rate of blood flow to suit organ needs
- smooth muscle in tunica media
- distinct internal + external elastic laminate, thick tunica media

Question 8

Arterioles (3)

Answer 8

• capable of vasodilation and vasoconstriction
• control blood flow to organs
• involved in blood pressure control

Question 9

Capillaries (5)

Answer 9

• connect Arterioles and venules
• site of gaseous exchange
• thin walls facilitate diffusion
• slow blood flow
• structure permits 1-way exchange

Question 10

Types of capillary?

Answer 10

Continuous - smooth + skeletal muscle

Fenestrated - pores penetrate endothelium for rapid exchange of water / large solutes

Sinusoidal - spaces between endothelium cells for exchange of large solutes

Question 11

What are some features of capillary beds?

Answer 11

Metarterioles - supplies a single capillary bed and continues a channel to vein

Precapillary sphincter - guards entrances to capillaries

Arteriovenous anastomoses - form direct channel between arteriolar + venule

Question 12

What do the terms proximal and distal refer to?

Answer 12

Positioning in the body that is closer to the centre. E.g. your foot is more distal than your torso, and your torso is more proximal than your foot

Question 13

What do the terms superior and inferior refer to?

Answer 13

The physical height at which something is positioned on the body.
E.g. your head is superior to your foot, and your foot is inferior to your head

Question 14

What do the terms medial and lateral refer to?

Answer 14

How close something is the the centre of the body from a sideways perspective.
E.g. your heart is more medial than your hand, and your hand is more lateral than your heart

Question 15

What do the terms anterior (ventral) and posterior (dorsal) refer to?

Answer 15

The position of something depending on how far forwards it is in your body.
E.g. your nose is more anterior than the back of your head.

Question 16

What is the transverse plane?

Answer 16

The plane that separates the body at the waist

Question 17

What is the coronal plane

Answer 17

The plane that separates the front and back of the body (cuts from left to right)

Question 18

what is the Sagittal plane

Answer 18

The plane that separates the left and right side of the body - plane cuts through from front to back

Question 19

What are the different blood circulatory systems?

Answer 19

• Systemic
• pulmonary
• other specialised circulatory systems (portal, coronary, foetal)

Question 20

What do circulatory systems transport? (6)

Answer 20

• O2
• nutrients
• CO2
• metabolic waste
• cells of immune system (WBC’s)
• Hormones

Question 21

How does the pulmonary circulatory system flow

Answer 21

Takes blood low in oxygen from the right side of the heart to the lungs
Takes blood rich in oxygen from the lungs to the left side of the heart

Question 22

Lymphatic system

Answer 22

• network of lymph vessels
• lymph
• lymphatic tissues and organs

Functions:
Involved in body’s defence mechanisms
Provides a mechanism for the drainage of interstitial fluid

Question 23

How does capillary exchange work?

Answer 23

• capillary blood pressure pushes fluid out of the capillary into interstitial fluid
• filters nutrients and gases
• blood colloidal osmotic pressure then pulls fluid back into the capillary, reabsorbs wastes and gases

Question 24

Describe the process of lymphatic drainage

Answer 24

Lymph capillaries -> lymph vessels -(via lymph nodes)-> lymph trunks -> thoracic duct or right lymphatic duct

• RLD drains lymph from right side of head + thorax via right subclavian vein
• TD drinks lymph from remainder of the body via left subclavian vein