Musculoskeletal System

Question 1

what are the three basic skeletons found in organisms

Answer 1

1. hydrostatic skeleton
2. exoskeleton
3. endoskeleton

Question 2

what is the function of the hydrostatic skeleton and an example

Answer 2

a volume of fluid enclosed within body of an organism that acts as a skeleton
- provides support and shape to organsim

eg. in amoeba

Question 3

what is the function of the exoskeleton and an example

Answer 3

hard external covering that protects and supports the organism eg. in insects and molluscs

Question 4

what is the function of the endoskeleton and an example

Answer 4

internal skeleton that supports the organism from the inside eg. in trees and vertebrates

Question 5

the musculoskeletal system is comprised of the (…) and (…) systems of the body. the systems are independent but they work together to perform many functions

Answer 5

the musculoskeletal system is comprised of the skeletal and muscular systems of the body. the systems are independent but they work together to perform many functions

Question 6

the skeletal system comprises the (…) and (…) of the organism

Answer 6

the skeletal system comprises the bones and cartilage of the organism

Question 7

what are the functions of the skeletal system

Answer 7

1. attachment
2. framework
3. haematopoiesis (RBC development from bones with red bone marrow)
4. mineral homeostasis (strength and mineral balance)
5. movement
6. protection
7. lipid storage (yellow bone marrow)

Question 8

what is bone made of?

Answer 8

1/4 water
1/4 bone cells (osteoid) - organic
1.2 calcium phosphate- inorganic

Question 9

what are the two types of bone? and an example

Answer 9

1. long bones- have shaft eg. tibia

2. short/irregular/flat/sesamoid bones- no shaft eg. sternum

Question 10

outline the structure of a long bone

Answer 10

1. shaft/diaphysis contains compact bone with a marrow cavity containing yellow bone marrow
2. 2 ends/epiphyses have an outer covering of compact bone with cancellous bone inside
3. metaphases area: in mature bones, area between diaphyses and epiphyses vs in a growing bone, epiphyseal cartilage/plate separates diaphysis from epiphyses (ossifies at end of growth)

Question 11

how does a long bone thicken?

Answer 11

1. new bone tissue is deposited under the periosteum (vascular connective tissue membrane covering bone) which has osteoclasts and osteoblasts
2. hyaline cartilage covers the epiphysis where bone forms joint with other bone

Question 12

outline the structure of short/irregular/flat and sesamoid bones

Answer 12

1. thin outer layer of compact bone
2. inside contains cancellous bone which contains red bone marrow
3. except cranial bones(has non adherent dura matter), the rest are covered by periosteum

Question 13

what are the four types of cells found in bone

Answer 13

1. osteogenic (undifferentiated stem cells)
2. osteoblasts (bone forming or bone building cells)
3. osteocytes (cells formed by the trapping of osteoblasts in a developing bone matrix)
4. osteoclasts (cells responsible for the reabsorption of bone to achieve or maintain optimal shape

Question 14

what would bone tissue contain

Answer 14

1. bone cells
2. compact bone and Haversian system
3. cancellous bone
4. blood vessels
5. nerve supply

Question 15

what is compact/cortical bone

Answer 15

bone with very few spaces between its compartments and can look solid to the naked eye
- many Haversian systems/osteons found in compact bone

Question 16

what is the function of cortical bone

Answer 16

form the external layer of all bone and is the main component of diaphyses of long bones
- provide protection, support, resistance to stress by weight and movement

Question 17

what is the Haversian system composed of

Answer 17

1. central Haversian canal contains lymph, nerve and blood vessels which are surrounded by calcified plates of bone (lamellae)
2. between lamellae are lacunae (tiny spaces) containing osteocytes and extracellular fluid
3. canaliculi connect lacuna to each other and to central Haversian canal

Question 18

where is cancellous bone found

Answer 18

where there is little stress or where stress comes from many directions (light, so moves easily by muscle)
2. ribs, backbone, breastbone, hips, ends of longbows

Question 19

what is the structure of cancellous bone

Answer 19

• not contain Haversian canals, looks like honeycomb
• contains trabecular of few lamellae (calcified plates of bone) and osteocytes interconnected by canaliculi
• spaces between trabeculae contain red bone marrow that produces blood cells

Question 20

what is the function of cancellous bone

Answer 20

protects and supports the red bone marrow