Musculoskeletal system

Question 1

Skeletal muscle

Answer 1

voluntary physical activities, attached to bones
(movement and posture)

Question 2

Cardiac muscle

Answer 2

heart muscle

Question 3

Smooth muscle

Answer 3

internal organs, involuntary

Question 4

Extensibility

Answer 4

Ability to be stretched

Question 5

Elasticity

Answer 5

ability to return to original length

Question 6

Tendons

Answer 6

fibrous connective tissue that attaches muscles to bones

Question 7

Belly

Answer 7

fleshy portion of the muscle

Question 8

Antagonistic pairs

Answer 8

Muscles can only contract to pull a bone, they can not push it away. So muscles that move bones are always grouped in pairs know as antagonistic pairs.
eg. biceps and triceps work together to move humerus

Question 9

Origin

Answer 9

The end of the muscle attached to the stationary bone

Question 10

Insertion

Answer 10

the end of the muscle attached to the moveable bone

Question 11

Agonist

Answer 11

muscle that causes desired action

Question 12

Antagonist

Answer 12

the muscle that relaxes while the agonist contracts

Question 13

Synergists

Answer 13

muscles that help indirectly in steadying a joint during a particular movement.

Question 14

Fixator

Answer 14

When a synergist immobilises a joint

Question 15

Muscle tone

Answer 15

when skeletal muscles maintain partial contraction

Question 16

How are muscle cells held together

Answer 16

in bundles that are held together by a layer of CT

Question 17

Sarcolemma

Answer 17

The cell membrane that surrounds a muscle fibre

Question 18

Sarcoplasm

Answer 18

The cytoplasm in the sarcolemma

Question 19

Transverse tubules

Answer 19

narrow tubes that are continuous with sarcolemma and extend at right angles into the sarcoplasm.

Question 20

Sarcoplasmic reticulum

Answer 20

membrane similar to endoplasmic reticulum. Forms a tubular network around each Myofibril. Releases Calcium ions in muscle contraction.

Question 21

Structure of skeletal muscles (5 things)

Answer 21

muscle
muscle fibre bundle
muscle fibre
myofibrils
myofilaments

Question 22

Z lines

Answer 22

The boundary between adjacent sarcomerers

Question 23

Sarcomeres

Answer 23

the contractile units of skeletal muscle

Question 24

Actin

Answer 24

thin myofilaments

Question 25

Myosin

Answer 25

thick myofilaments

Question 26

Thin filaments consist of:

Answer 26

-twisted strands of molecules of actin
-Strands of tropomyosin – double-stranded proteins that cover the active sites and prevent actin-myosin interaction
-A troponin –

Question 27

Thick filaments consist of:

Answer 27

-myosin molecules.

Question 28

Contraction of a skeletal muscle summary

Answer 28

1. A nerve impulse reaches the muscle
2. Calcium ions are released and bind to tropomyosin-troponin complex -> which makes active site available
3. Myosin head attaches to active site on actin (forms cross-bridge)
4. Myosin springs forwards in power stroke which pulls on actin fibres
5. As actin and myosin slide across each other the individual sarcomeres shorten bringing the Z-lines closer together
6. As many sarcomeres shorten -> muscle fibres shorten -> muscle contraction

Question 29

6 functions of skeleton

Answer 29

-support
-attachment
-movement
-protection
-storage
-red blood cell production

Question 30

4 types of bones

Answer 30

-long bone eg. all limb bones so humerus, femur
-short bone, cube shaped eg. carpals, tarpals
-flat bone eg. cranium, sternum, ribs
-irregular eg. vertebrae and coccyx

Question 31

Ossification

Answer 31

The process of forming bone

Question 32

Epiphyseal lines

Answer 32

bone growth areas in children

Question 33

Osteon

Answer 33

The structural unit of compact bone

Question 34

Trabeculae

Answer 34

The thin bony plates that make up spongy bone

Question 35

Where does bone growth occur?

Answer 35

the diaphysis and in the two epiphyses.

Question 36

The 4 main steps in bone formation

Answer 36

-The cartilage undergoes calcification through the
deposition of calcium salts.

-The cartilage cells die and are replaced with OSTEOBLASTS which promote more deposition of calcium salts.

-Osteoblasts mature into OSTEOCYTES.

-Bone formation continues until only a small band of cartilage remains. The remnants of this area are known as the EPIPHYSEAL LINES when the bone stops growing.

Question 37

Osteoblasts

Answer 37

form bone by promoting deposition of calcium salts into matrix

Question 38

Osteoclasts

Answer 38

cells that reabsorb bone by secreting enzymes that dissolve the matrix, which release the stored minerals.

Question 39

Osteoporosis is caused by …

Answer 39

Osteoclasts removing calcium salts faster than osteoblasts deposit them, causes bone to weaken leading to Osteoporosis.

Question 40

3 types of cartilage

Answer 40

Hyaline
Elastic
Fibrocartilage

Question 41

Structure and function of hyaline cartilage

Answer 41

Collagenous fibres are thin and tightly packed
Function: provides support and flexibility, makes up rings of trachea and bronchi and found at the end of bones

Question 42

Structure and function of elastic cartilage

Answer 42

Has elastic fibres as well as collagenous fibres, but they are more spread out.
Function: provides shape and support to places such as ears and nose

Question 43

Structure and function of fibrocartilage

Answer 43

Has thick, coarse collagenous fibres that are arranged in parallel bundles. fibres are less compacted than hyaline and so is able to be compressed slightly.
Function: acts as a cushion between bones such as between the vertebrae and in the miniscus of the knee joint