Lecture 5 - Bone Physiology

Question 1

Functions of the Skeletal System (5 points)

Answer 1

Support against gravity
Leverage for muscle action
Internal organ protection
Storage
Blood cell production

Question 2

3 substances stores in Skeletal System

Answer 2

Calcium (for muscle contraction)
Phosphorus
Fat

Question 3

6 types of bones

Answer 3

Flat
Long
Short
Irregular
Sutural
Sesamoid

Question 4

3 Features of Long Bones

Answer 4

Diaphysis (shaft)
Epiphysis (ends)
Articular Cartilage

Question 5

2 parts of Diaphysis

Answer 5

Compact Bone
Medullary Cavity

Question 6

Function of Medullary Cavity

Answer 6

Stores yellow bone marrow

Question 7

Function of Epiphysis

Answer 7

Forms joints

Question 8

3 parts of Bone Tissue

Answer 8

Ground Substance
Protein
Bone Cells

Question 9

Bone Ground Substance Features (2 points)

Answer 9

Two thirds of bone matrix
Contains minerals such as hydroxyapatite

Question 10

Bone Protein Features (2 points)

Answer 10

One third of bone matrix
Mostly type I collagen fibres

Question 11

3 types of Bone Cells

Answer 11

Osteoblasts
Osteocytes
Osteoclasts

Question 12

Osteoblast Definition

Answer 12

Immature Bone Cell

Question 13

Osteoblast Function

Answer 13

Secretes Matrix Proteins

Question 14

Osteocytes Definition

Answer 14

Mature Bone Cell

Question 15

Osteocytes Function

Answer 15

Maintains bone matrix
Detect forces in bone

Question 16

Osteoclasts Definition

Answer 16

Multinucleate bone cell between medullary cavity and bone matrix

Question 17

Osteoclasts Function

Answer 17

Secretes acids and enzymes to dissolve bone matrix

Question 18

4 parts of compact bone

Answer 18

Osteon - Basic functional unit, surrounds central canal
Central Canal - Tunnel for blood vessels
Lamellae - Concentric Layers of Matrix
Lacunae - Contains osteocytes

Question 19

3 parts of Trabecular Bone

Answer 19

Trabeculae
Red Marrow
Yellow Bone Marrow

Question 20

Features of Trabeculae (3 points)

Answer 20

Contains Arches, rods and plates of bone
Branching network
Strong

Question 21

Features of Red Marrow (3 points)

Answer 21

Between trabeculae
Forms red blood cells
Provides nutrients of osteocytes

Question 22

Features of Yellow Bone Marrow (2 points)

Answer 22

Found in medullary cavity
Stores fat

Question 23

Strength distribution in bone

Answer 23

Compact bone provides strength in long axis
Trabecular Bone provides strength in range of directions

Question 24

Periosteum Definition

Answer 24

2 layer membrane outside bone

Question 25

2 layers of Periosteum

Answer 25

Outer Fibrous Layer Inner Cellular Layer

Question 26

Endosteum Definition

Answer 26

Membrane lining bone

Question 27

3 lines of Endosteum

Answer 27

Medullary Cavity Central Canals Trabeculae

Question 28

Ossification Definition

Answer 28

Formation/Conversion of bone

Question 29

3 types of bone formation/growth

Answer 29

Intramembraneous Ossification Endochondral Ossification Appositional Bone Growth

Question 30

Intramembraneous Ossification Definition

Answer 30

Flat Bone Formation

Question 31

Endochondral Ossification Definition

Answer 31

Formation from cartilage model

Question 32

Appositional Bone Growth Definition

Answer 32

Bone Growth in width

Question 33

4 steps of Intramembraneous Ossification

Answer 33

Mesenchymal Cells differentiate into osteoblasts Ossification forms spicules of bone Trabecular Bone formed Remodeled into compact bone

Question 34

Intramembraneous Ossification Example

Answer 34

Cranial Bones in Skull

Question 35

5 steps of Endochondral Ossification

Answer 35

Chondrocytes within matrix enlarge then die Osteoblasts cover the shaft in thin layer of bone Blood vessels/Osteoblasts penetrate to form primary ossification centre Primary ossification centre enlarges Secondary ossification centre formed at epiphysis

Question 36

Growth in Bone Length

Answer 36

Bone grows as cartilage from epiphyseal plate

Question 37

2 steps in Appositional Bone Growth

Answer 37

Bone deposited by osteoblasts Bone resorbed by osteoclasts

Question 38

Requirements for normal bone growth

Answer 38

Calcium/Phosphate Vitamin D Growth Hormones Forces applied to bone

Question 39

Bone Remodeling Features

Answer 39

Continuous Breakdown/reforming of bone tissue Adaptation of loading Calcium homeostasis

Question 40

2 Hormones used in Calcium homeostasis

Answer 40

PTH - bone resorption to release calcium Calcitonin - bone formation to store calcium

Question 41

4 steps of Fracture repair

Answer 41

Clot formation Formation of external callus/internal callus External callus replaced by bone, Internal callus unites broken ends Initial swelling eventually remodeling

Question 42

External Callus Definition

Answer 42

Cartilage

Question 43

Internal Callus Definition

Answer 43

Spongy bone