13 - Bone and Blood

Question 1

What are the 5 different types of bone?

Give an example for each.

Answer 1

• Long (humerus)
• Short (trapezoid - wrist)
• Flat (sternum)
• Irregular (vertebra)
• Sesamoid (patella)

Question 2

What is the function of the long bones?

Answer 2

• Support the weight of the body

- Facilitate movement

Question 3

What is the function of the short bones?

Answer 3

Provide stability and some movement

Question 4

What is the function of the flat bones?

Answer 4

• Protect internal organs

- Provide large areas of attachment for muscles

Question 5

What is the function of the irregular bones?

Answer 5

• Protect internal organs

- Important anchor points for muscle groups

Question 6

What is the function of the sesamoid bones?

Answer 6

Protect tendons from stress and damage

Question 7

What are the two types of bone?

Answer 7

• Cancellous bone

- Compact bone

Question 8

What is the structure and function of red bone marrow?

Answer 8

• Full of developing blood cells
• Rich blood supply
• Only in spongy (cancellous) bone

Functions to replenish cells in the blood (haemopoiesis)

Question 9

What is the structure and function of yellow bone marrow?

Answer 9

• Full of adipocytes
• Poor blood supply

Shock absorber and energy source. Can convert into red marrow.

Question 10

Cancellous bone is structured in a sponge-like arrangement called ………..

Answer 10

Trabeculae

Question 11

What are:

• Osteocytes
• Osteoblasts
• Osteoclasts

Answer 11

• Osteocytes - cells of bone
• Osteoblasts - make new bone
• Osteoclasts - breakdown bone

Osteoblasts and osteoclasts are on the surface of the osteon to remodel the bone

Question 12

Maturing blood cells leave the bone marrow into ……………….. blood vessels

Answer 12

sinusoidal

Question 13

When new RBCs enter the circulation from the bone marrow, how long do they take to mature?

Answer 13

2 days

Question 14

Immature WBCs need to be activated, where are T cells and B cells activated?

Answer 14

T cells - thymus and lymphatics

B cells - already mature

Question 15

Flow in capillaries is controlled by ……….. …………. between the arterioles and capillaries

Answer 15

Precapillary sphincters

Question 16

Larger cells cannot pass through capillaries (e.g. WBCs), how do they get from the arteriole to the venule?

Answer 16

Via throughfare channels called antriovenous anastomoses

Question 17

What tissues are present in the three layers of a vein?

Answer 17

• Tunica intima - endothelial cells
• Tunica media - elastic fibres and smooth muscle cells
• Tunica externa - elastic fibrous capsule

Question 18

Veins are a low pressure system so flow towards the heart is assisted by …

Answer 18

• Valves to assist flow against gravity (fibroelastic cartilage)
• Muscle contractions and lung expansion compresses veins preventing backflow and pumping blood

Question 19

What are the two primary groups of vein? How do they differ in terms of the blood they carry?

Answer 19

Pulmonary veins - oxygenated blood from the lungs

Systemic veins - deocygenated blood from the rest of the body

Question 20

What is the range of size of a vein?

Answer 20

1 mm to 1.5 cm

Question 21

What tissues are present in the three layers of an artery?

Answer 21

• Tunica intima - elastic membrane and very tight endothelium
• Tunica media - elastic fibres and smooth muscle cells (thicker than in veins)
• Tunica externa - collagen and elastic fibres

Question 22

Why does the tunica externa (adventitia) of an artery contain collagen when veins don’t?

Answer 22

Allows the artery to stretch but prevents over expansion due to the higher blood pressure than in veins