Bones

Question 1

What is homeostasis?

Answer 1

The dynamic process of keeping a stable internal environment

Question 2

Feedback vs feedforward

Answer 2

feedback: Responds to a change after it has happened. 2 types
- negative: returns to midline
- positive: accelerates away from midline

Feedforward: Happens when predicting a future change

Question 3

3 types of Bodily fluid and their percents

Answer 3

1. Intrastitial fluid: 67%
2. Interstitial fluid: 26%
3. Plasma: 7%

Question 4

Types of cells

Answer 4

1. Epithelial cells: form membranes in body
2. Connective tissue: connects and supports the body (eg. tendons, bones, blood)
3. neurone cells: produced and conducts electrical signals
4. Muscle cells: Can contract

Question 5

Types of bones

Answer 5

1. Flat bone (skull)
2. irregular bone (vertibrae)
3. long bone (Humorous)
4. short bone (Carpal bones)

Question 6

Epithelial cell naming

Answer 6

Shape:
1. Cuboidal (cube)
2. Squamous (Squished)
3. columnar (long)
4. transitional (changes shape)

Layers:
1. Simple (1 layer)
2. stratified (multi layered)
3. Pheudostratified (Multi layered not uniform cells)

Question 7

Types of connective tissue

Answer 7

1. Connective tissue proper: Connects and attaches
2. lymph and blood: Transport around the body
3. Bones: support and structure
4. Cartilage: shock absorption

Question 8

Long bone anatomy

Answer 8

1. Diaphysis: Long part of the bone
2. Metaphysis: Flared part of the bone
3. Epiphysis: Ends of the bone
4. Epiphyseal plate/line: line between the epiphysis and the metaphysis
5. Articular cartilage: around the end of the bone reduces friction and shock absorption
6. medullary cavity (cavity in the middle of bone)
7. Endosteum: lines the medullary cavity
8. Periosteum: bilayered butter membrane of the bone

Question 9

What are the two layers of periosteum?

Answer 9

1. Outer fibrous layer: dense connective tissue
2. Inner osteogenic layer: holds osteoblast and osteoclasts

Question 10

What are the honey comb like structures in spongy bone called?

Answer 10

Trebeculae

Question 11

Where is yellow/red bone marrow found and their rolls?

Answer 11

Yellow bone marrow: Found in the medullary cavity and stores adipose tissue (fat tissue) for energy storage

Red bone marrow: Found in spongy bone and produced red and white blood cells and platelets

Question 12

Name the specific veins and arteries that supply the different areas of the bone. 4 types

Answer 12

1. Nutrient artery and vein: Supply the diaphysis
2. Epiphyseal vein and artery: Supply the epiphysis
3. Metaphysical artery and vein: supply the metaphysis
4. Periosteal vein and artery: supply the periosteum

Question 13

Name the parts of compact bone and their uses

Answer 13

1. Osteons: cylindrical units of compact bone
2. Concentric lamellae: rings of bone that make up the osteons
3. Collagen fibres: Make up the concentric lamellae, running in opposite directions as the previous ring to increase strength
4. Circumferential lamellae: Bone that surrounds the diaphysis
5. lacunae: gaps in between the osteons. House osteocytes
6. Canaliculi: small canals that run between lacunae providing nutrient and waste removal
7. Central canal: canal down the centre of the osteoblasts containing blood vessels and nerves

Question 14

4 reasons for bone development

Answer 14

1. fetal development
2. Repair from a fracture
3. Early life bone growth
4. Bone remodelling through life

Question 15

2 types of bone development and their definitions

Answer 15

ossification: specific process of creating new bone
osteogenesis: General term for bone development and maintenance. Ossification is a type of osteogenesis

Question 16

2 types of ossification

Answer 16

1. Endochondral ossification: Mesenchymal cells develop into cartilage model first, then bone replaces the cartilage. (most bones are made this way)
2. Intramembranous ossification: Mesenchymal cells differentiate straight into bone (forms flat bones)

Question 17

Intramembranous ossification in depth (layer of spongy bone between 2 layers of compact bone)

Answer 17

1. Mesenchymal cells differentiate into osteoblasts and secrete osteoid
2. Osteoid is played around the blood vessels forming trebeculae
3. Minerals calcify the osteoid into bone
4. Osteoblasts go to the surface off the cell and create the periosteum
5. just below the periosteum, spongy bone is remodelled into compact bone
6. Blood vessels in the spongy bone remodel into red bone marrow

Question 18

explain the process of Endochondral ossification:

Answer 18

see page in binder

Question 19

Post natal bone growth 2 ways

Answer 19

Interstitial growth: growth in length. Chondrocytes keep dividing and extending the bone then osteoblasts turn them into bone

Appositional growth: Growth in width. Osteoblasts create new layers of compact bone widening it out.

Question 20

Interstitial growth: the growth plate. IMPORTANT (Ask about is calcification what makes bone)

Answer 20

Resting zone: Chondrocytes anchor the growth plate to the epiphysis

Prolific zone: Chondrocytes rapidly divide lengthening the bone

Hypertrophic zone: Old chondrocytes increase in size forming the lacunae between them

calcification zone: Old chondrocytes die, opening spaces for blood vessels to enter. The cartilage is calcified

Ossification zone: Osteoclasts remodel the cartilage into bone

Question 21

Appositional growth in depth

Answer 21

1. Osteoblasts on the periosteum form around the blood vessels creating new concentric lamellae, until new osteons are formed
2. Osteoblasts form new circumferential lamellae
3. Osteoclasts widen the medullary cavity

Question 22

In adults what kind of bone growth occurs?

Answer 22

Only appositional growth. The growth plate is fused into the epiphyseal line, therefor no interstitial growth

Question 23

What affects our peak bone mass?

Answer 23

1. genes
2. life style (diet, exersize)

Question 24

What hormone is released if calcium is too low and what does it do?

Answer 24

Parathyroid hormone: Kidneys re-absorb more calcium. Stimulates osteoclast activity to break down bone for calcium. Synthesized more vitaminD which increases calcium absorption

Question 25

What hormone is released if calcium levels are too high?

Answer 25

calcitonin: Osteoclast activity is inhibited (won't put more calcium into plasma). promotes osteoblast activity. tells kidneys to reduced calcium re absorption

Question 26

What is wolfs law?

Answer 26

Bones become thicker and stronger to resist forces and thinner and weaker if their are no faces acting on it