skeletal system

Question 1

What are the major functions of bones?

Answer 1

*support
*protection
*assistance in movement
*mineral storage and release
*blood cell protection

Question 2

What makes up the skeletal system?

Answer 2

*bones
*associated connective tissues
- cartilage
-tendons
-ligaments

Question 3

What does the cartilage do?

Answer 3

*protects joins

Question 4

What do the tendons do?

Answer 4

*connects muscles to bone

Question 5

What do ligaments do?

Answer 5

*connects bones to bones

Question 6

What is the axial part of the ss?

Answer 6

*axial= all along the axis
- 80 bones
- houses vital parts of the body

Question 7

What is the appendicular part of the ss?

Answer 7

*appendicular = appendage
*126 bones
*locomotion

Question 8

What are the type of bones?

Answer 8

*sesamoid (lie within tendons)
*short bones
*flat bones
*long bones
*irregular bones

Question 9

What is the structure of compact bone?

Answer 9

*dense and solid in appearance
*protecting and strength
*repeating circular units
-osteons

Question 10

What is the structure of the cancellous (spongy) bone?

Answer 10

*characterised by open space partially filled with needle like structures = trabeculae
*strength without weight

Question 11

What types of bone is in short, flat and irregular bones?

Answer 11

*inner portion = cancellous/ spongey bone
*outer portion = covered on the outside with compact bone

Question 12

What types of bone make up the long bone?

Answer 12

*diaphysis (middle)
*outside - compact bone
*inner - spongy
*both ends of bone have epiphyses
= cancellous/ spongy in this region
*epiphyseal line = growth plate, bone will only extend in this region (new cells multiply here)

Question 13

What is a part of the inorganic composition of bone matrix?

Answer 13

*inorganic salts
*hydroxyapatite
*chemical crystals of calcium and phosphate
*compression strength

Question 14

What is a part of the organic composition of bone matrix?

Answer 14

*organic matrix
*composite of collagen (rope like) fibres and proteoglycans
*flexible strength

Question 15

What is bone marrow like? + what are the two types of marrow?

Answer 15

*specialised soft like diffuse connective tissue
*red marrow
*yellow marrow

Question 16

Where is red marrow found + what it produces?

Answer 16

*found in all bones in an infants or Childs body
*produce red blood cells

Question 17

Where is yellow marrow found + what it produces?

Answer 17

*as an individual ages, red marrow is replaced by yellow marrow
*marrow cells become saturated with fat and are no longer active in blood cell production

Question 18

What do progenitor cells develop into?

Answer 18

osteoblasts

Question 19

What do osteoblasts do?

Answer 19

Bone-forming cells found in all bone surfaces
Ossifiction/osteogenesis
Secretes organic component – collagen
Produce vesicles: release Ca2+ and phosphate ions which contribute to hydroxyapatite formation
Osteoid
cannot divide again (no mitosis)

Question 20

What do osteoblasts develop into?

Answer 20

osteocytes

Question 21

What do osteocytes do?

Answer 21

Differentiated mature non-dividing osteoblasts
Trapped in lacuna and serve mainly as mechanosensors/ mineral homeostasis,
*cannot divide (no mitosis)

Question 22

What do osteoclasts do?

Answer 22

Giant cells
Resorb bone through dissolving mineral and breaking down collagen
The “macrophages” of bone
(develop from blood cells called monocytes and macrophages)

Question 23

What is entailed in bone remodelling?

Answer 23

*removal of existing bone by osteoclasts and the deposition of new bone by osteoblasts
*growth
*changes in bone shape
*the adjustment of bone to stress
*bone repair
*calcium ion regulation in the body fluids

Question 24

What is entailed in the regulation of blood calcium levels?

Answer 24

*stores 98% of calcium reserves
*osteoblasts remove calcium from blood
*osteoclasts release calcium into blood
*calcium homeostasis:hormonal control
regulated by the parathyroid hormone(released when low lvl)
Vitamin D,(released when low lvl) Calcitonin (released when high lvl)

Question 25

What does the PTH do?

Answer 25

Primary regulator
Stimulates osteoclasts to breakdown bone matrix
Increases kidney absorption of calcium from urine

Question 26

What does Vit D do?

Answer 26

*increases the absorption of calcium from the small intestine
*increases blood calcium levels

Question 27

What does Calcitonin do?

Answer 27

*hormone produced in the thyroid gland
*stimulates bone deposition by osteoblasts
*inhibits osteoclast activity
*decreases blood calcium levels

Question 28

What happens to the structure of aging skeleton?

Answer 28

*Decreased collagen makes bones more brittle
*Cancellous bone lost first
*Decrease in no of trabeculae
*Followed by compact (lesser)
*Incomplete remodelling