musculoskeletal system

Question 1

list the function of the skeletal system

Answer 1

support

storage - minerals, fats, salts

attachment - for bones to muscles

articulation - when 2 bones move around each other

protection

production - of RBCs

Question 2

explain what the epiphyses is in the structure of a long bone

Answer 2

ends of the bone

Question 3

explain what the diaphyses is in the structure of a long bone

Answer 3

the main shaft, hollow cylinder of compact bone surrounding a cavity

Question 4

explain what compact bone is in the structure of a long bone

Answer 4

forms the cortex/hard outer shell of most bones

very dense and rigid

filled with tiny holes that hold blood vessels

protects spongey bone and bone marrow

Question 5

explain what spongey bone is in the structure of a long bone

Answer 5

bone on the inside

porous and has large spaces filled with marrow

Red bone marrow in flat and long bones, produces RBCs, WBCs and platelets

Question 6

explain what the medullary cavity is in the structure of a long bone

Answer 6

hollow cavity in the diaphyses, filled with yellow bone marrow for fat storage

Question 7

explain what articular cartilage is in the structure of a long bone

Answer 7

Covers epiphysis for protection and cushioning

Question 8

explain what epiphyseal lines are in the structure of a long bone

Answer 8

Bone growth areas

Question 9

what is an osteoblast

Answer 9

Secrete bone matrix around themselves until nutrients struggles to reach osteoblast when matrix becomes dense and can’t diffuse

When oxygen is low enough, combines with chemical signals, the osteoblasts differentiate into an osteocyte

Question 10

what is an osteocyte

Answer 10

Bone cell

Maintains bone tissue

Question 11

what is an osteon

Answer 11

Basic unit of bone cells (whole individual circle in diagrams)

Question 12

what is the Haversian canal

Answer 12

Centre of osteon, blood vessel run up it to deliver nutrients to osteocyte

Question 13

what are the lamellae

Answer 13

Concentric layers surrounding central canal

Forms 3 layers

Question 14

what are the lacunae

Answer 14

Spaces in lamellae where osteocytes live

Question 15

what are the canaliculi

Answer 15

Small crevices moving nutrients between osteocytes from the central canal

Run across from lamellae

Deliver nutrients from lacunae to lacunae

Question 16

what is the process of bone formation/growth called

Answer 16

ossification

Question 17

what are the 2 types of ossification processes

Answer 17

endochondral ossification- long bones

intramembranous ossification - flat bones

Question 18

explain the process of endochondral ossification

Answer 18

Chondrocytes secrete cartilage matrix

Chondrocytes within the cartilage absorb the surrounding cartilage matrix

The matrix calcifies and the chondrocytes die

Stem cells in the pericardium divide to form osteoblasts

The periosteal bud (consisting of capillaries) form the primary ossification centre

Bone development from the osteoblasts extends toward epiphyses

Same process is repeated in epiphyses  second ossification centres formed

Calcified cartilage is replaced with spongey bone

Osteoclasts reabsorb bone in the diaphysis creating a hollow medullary cavity

Remaining cartilage is over epiphyses forming articular cartilage.

Question 19

explain the process of intramembranous ossification

Answer 19

Mesenchymal cells differentiate into osteoblasts

Osteoblasts lay down osteoid – organic part of bone made of collagen fibres

Some osteoblasts become entrapped in the osteoid and becomes an osteocyte

The osteoid calcifies and forms a type of spongey bone called spicules

These aggregate in small connecting beams called trabeculae

As trabeculae thicken they form compact bone

The blood vessels on the outside of the cells condense to form the periosteum

Question 20

what is a joint

Answer 20

A site where 2 bones come together

Question 21

what are the 3 types of joints

Answer 21

fixed

cartilaginous

synovial

Question 22

explain what a fixed joint is

Answer 22

no movement, held by fibrous connective tissue e.g. sutures in skull

Question 23

explain what a cartilaginous joint is

Answer 23

slight movement, held in place by cartilage e.g. symphysis pubis, between vertebrae

Question 24

explain what a synovial joint is

Answer 24

amount of movement only limited by ligaments, tendons and adjoining bones e.g. shoulder, wrist, knee,

Question 25

list the different types of synovial joints

Answer 25

ball and socket gliding saddle hinge pivot condyloid

Question 26

explain what a ball and socket joint is

Answer 26

Form when the spherical head of one bone fits into a cup-like cavity of another E.g. head of humorous into scapula, head of femur fit with pelvis

Question 27

explain what a hinge joint is

Answer 27

Allow movement in one plane only Form when the convex surface of 1 bone fits into the concave surface of another E.g. elbow, knee, ankle

Question 28

explain what a pivot joint is

Answer 28

Formed when the rounded, pointed or conical end of 1 bone articulates with a ring, formed partly by a bone and partly by a ligament E.g. joint between the first vertebrae and skull, between radius and ulna

Question 29

explain what a gliding joint is

Answer 29

Allow movement in any direction in a side-to-side or back-and-forth motion Restricted only by ligaments of bony processes E.g. between carpals, between tarsals, between sternum and clavicle

Question 30

explain what a saddle joint is

Answer 30

2 bones forming the joint are both saddle shaped They fit together in a way that allowed side-to-side movement and back and forth movement E.g. where the thumb joins the palm of the hand

Question 31

explain what a condyloid joint is

Answer 31

Have 1 surface of bone slightly convex that fits into a slightly concave depression of another They allow for movement in 2 directions (up and down and side to side) E.g. between radius and carpals between metacarpals and phalanges

Question 32

what is the synovial cavity in a joint

Answer 32

The space between synovial joints

Question 33

what is the articular capsule in a joint

Answer 33

Surrounds and encloses the joints ``` Fibrous capsule: - Dense, fibrous connective tissue attached to periosteum of articulating bones - Holds bones together - Flexible and strong ``` Synovial membrane: - inner layer of capsule - Loose layer of connective tissue - Well supplied with blood vessels - Lines joint cavity - Secretes synovial fluid

Question 34

what is the synovial fluid in a joint

Answer 34

Fills joint cavity Lubricates joint and provides nourishment for cartilage cells Contains phagocytic cells Prevents articulating surfaces from touching

Question 35

what is the articular cartilage in a joint

Answer 35

Covers articulating surfaces Provides smooth surface for movement

Question 36

what are the articular discs

Answer 36

Made of fibrocartilage extends inward from the articular cartilage Divides synovial cavity in 2 so fluid is directed to areas of greatest friction

Question 37

what are the bursae in a joint

Answer 37

Little sacs of synovial fluid Prevent frictions between bone and ligament/tendon or bone and skin

Question 38

what are accessory ligaments in a joint

Answer 38

Holds bone together

Question 39

explain the sliding filament theory in term of contracting the muscle

Answer 39

1. Nerve impulses cause axon terminals to release acetylcholine 2. Acetylcholine initiates an impulse that travels into the T tubules and then into the sarcoplasmic reticulum 3. The sarcoplasmic reticulum is stimulated to releasee calcium ions 4. Calcium ions activate myosin which breaks down ATP and remove tropomyosin-troponin complex from the blocking activation sites on actin 5. Myosin heads attach to activation sites in actin, forming crossbridges 6. Through powerstrokes, the myosin heads pull along the actin and they slide past each other 7. This causes the sarcomere to contract

Question 40

explain the sliding filament theory in terms of relaxing the muscle

Answer 40

8. Acetylcholine is inactivated by acetylcholinesterase 9. Calcium ions are transported back into the sarcoplasmic reticulum using energy from the ATP breakdown 10. Low calcium ion concentration in sarcoplasm stops the enzyme activity of myosin 11. ADP is resynthesised into ATP and binds to the myosin crossbridges 12. Tropomyosin-troponin complex attached back to actin and myosin crossbridges separate 13. Thin myofilaments return to original position 14. Sarcomeres return to resting lengths, muscles fibres relax and muscles relax.

Question 41

what is osteporosis

Answer 41

Loss of bone mass and density impairs the bone’s normal function As bone density decreases, risk to bone fractures increases Even minor bumps/falls can results in serious fractures Most affected in ribs, vertebrae, pelvis Treatment: adequate calcium intake in their diet, plenty of exercise

Question 42

what is osteoarthirits

Answer 42

Gradual change in joints overtime Causes: irritation of joints, abrasion and wear Articular cartilage at joints deteriorates, bone surfaces are no longer protected The exposed bone wears away and bony spurs may develop from the exposed ends These spurs decrease space within the joint cavity and restrict movement at the joint Treatment: hydrotherapy, stretching, exercise