The Skeletal System

Question 1

*The skeletal system consists of:

Answer 1

1. Bones
2. Joints
3. Cartilage

Question 2

*Functions for the body:

Answer 2

1. Support and shape
2. Protection
3. Movement
4. Mineral reservoir
5. Blood cell formation

Question 3

Support and shape:

Answer 3

Supporting framework for body

Question 4

Protection:

Answer 4

E.g. skull protects the brain,

Rib cage protects heart and lungs

Question 5

Movement:

Answer 5

Bones and joints constitute levers. Muscles are anchored firmly to bones as muscles contract and shorten; they pull on bones, producing movement at a joint.

Question 6

Mineral reservoir:

Answer 6

Bones store calcium, phosphorus and certain other minerals.

Question 7

*Blood cell formation:

Answer 7

Vital process carried by red bone marrow

Question 8

*As an infant gets older, what does red bone marrow turn into?

Answer 8

Yellow marrow, which is inactive fatty tissue

Question 9

*Main adult red bone marrow sources:

Answer 9

Sternum 
Spinal Column
Base of skull
Upper arm 
And thigh

Question 10

*We can’t survive without red bone marrow because?

Answer 10

It forms blood cells

Question 11

*Types of bones:

Answer 11

Long bones (leg, arm)
Short bones (wrist, ankle)
Flat bones (ribs, skull)
Irregular bones (face bones, ear bones, spine or vertebrae)

Question 12

Structure of a long bone:

Diaphysis

Answer 12

• main shaft like portion

Composed of thick compact bone

Question 13

*Structure of long bone:

Epiphyses

Answer 13

• both ends of a long bone
• Yellow marrow fills spaces of spongy bone in most adult epiphyse; but not in proximal epiphyses and femur. These contain red bone marrow

Question 14

Structure of long bone:

Articulate cartilage

Answer 14

Thin layer of hyaline cartilage (glassy, translucent) that covers joint surfaces of epiphysis.

Question 15

*Structure of long bones:

Periosteum

Answer 15

• dense white fibrous membrane that covers bone, except at joint surfaces
• bone forming cells called OSTEOBLASTS, compose inner layer of PERIOSTEUM

Question 16

*Osteoblasts are essential for:

Answer 16

Bone cell survival and bone formation

Question 17

*Structure of long bones:

Medullary (or bone marrow) cavity

Answer 17

• tube like hollow in diaphysis of long bone

- in adult it contains yellow marrow

Question 18

Structure of long bone:

Endosteum

Answer 18

-membrane that lines medullary cavity of long bones

Question 19

Structure of long bones:

Compact bone

Answer 19

• hard and dense

- makes up main shaft of the long bone and the outer layer of other bones

Question 20

*Short, flat, irregular bones:

Answer 20

[Red bone marrow] fill spaces in spongy bone inside a few irregular and flat bone (e.g vertebrae)
The other irregular, short and flat bones contain [yellow bone marrow]

Question 21

*Microscopic structure of bone:

Answer 21

• bone consists of living and non living intercellular substance
• intercellular material (called matrix of bone) is more abundant than bone cells and it contains fibres of collagen

Question 22

*Bone differs from other connective tissue in that..

Answer 22

It is ridged, not soft and flexible; it is calcified (it has calcium in it)

Question 23

*Human skeleton consists of 2 main divisions:

Answer 23

1. Axial skeleton (74 bones)

2. Appendicular skeleton (126 bones)

Question 24

*Axial skeleton:

Skull

Answer 24

28 irregular shaped bones form the skull
Consists of 2 divisions:
1. Cranium (8 bones) 
2. Face (14 bones)
3. Ear (6 bones)

Question 25

*Spinal column (5):

Answer 25

(7) cervical vertebrae (12) thoracic vertebrae (5) lumbar vertebrae (1) sacrum (1) coccyx

Question 26

*Sternum:

Answer 26

- breast bone: dagger shaped bone - red marrow can be drawn up in a syringe by inserting needle through skin and bone; examined for abnormal or normal cells

Question 27

*Ribs:

Answer 27

12 pairs of ribs

Question 28

Skeletal differences in men and women:

Answer 28

Male skeleton generally larger and heavier

Question 29

*Age changes:

Answer 29

- As bones mature, they lose calcium - In most women, calcium loss from bone diseases develops after 40 y/o - femur especially vulnerable - if we live long enough, most of us will develop bone disease osteoporosis - generalized decrease in organic matrix - thinning of intervertebral disks

Question 30

**Bone growth and resorption: | A

Answer 30

Growth in length by continual thickening of epiphyseal (articular) cartilage followed by ossification (replacement of cartilage by bone)

Question 31

**Bone growth and resorption: | B

Answer 31

Growth in diameter- medullary cavity enlarged by osteoclasts destroying bone around it, while new bone is added around outside by osteoblasts (build)

Question 32

**Bone growth and resorption: | C

Answer 32

Opposing processes of bone tissue formation and destruction (resorption) go on concurrently through life. 1. (infancy to adolescence) bone formation exceeds resorption 2. (young adulthood) resorption balance each other 3. (after young adulthood) 35-40 bone resorption, than formed; become weaker and fracture easily

Question 33

*Osteocytes:

Answer 33

Mature bone cells

Question 34

**Factors that affect the development of bones include:

Answer 34

1. Genetic factors: length thickness of a bones are inherited 2. Nutrition: A balanced diet high in vitamin D and minerals such as calcium maintains a healthy bone development. 3. Hormones: affect the growth and development of bones hormones are chemical/messengers, which are sent via the blood supply to the bones. They are responsible for informing the bones about when to stop growing etc.

Question 35

*Cartilage:

Answer 35

- both resembles and differ from bone - flexible of a firm plastic material - cartilage has no blood vessels

Question 36

Response to stress:

Answer 36

- walking, jogging, and other forms of exercise subject bones to stress - they respond by laying down more collagen fiber, and mineral salts (e.g. calcium) in bone matrix

Question 37

*Skeletal system: | Articulations (joints)

Answer 37

Articulations in the body or joints between bones. Their purpose: •holds bones bound to one another or spine •Permit movement between them

Question 38

**Hyoid bone:

Answer 38

- Only free floating bone in the body - Helps with tongue movement - Helps with swallowing

Question 39

**Long bone: | Diagram

Answer 39

Left side: proximal epiphysis (top) Diaphysis (middle) ``` Right side: Endosteum Compact bone Medullary cavity Periosteum Artery Distal epiphysis (bottom) ```

Question 40

Collagen:

Answer 40

A fibrous protein that gives strength and resilience to tissue and bone matrix