Musculoskeletal System (Muscle)

Question 1

What does Origin mean?

Answer 1

CLOSER TO AXIAL
Attachment that moves least during muscle contraction

Question 2

What does Insertion mean?

Answer 2

CLOSER TO APPENDICULAR (DISTAL)
Attachment that moves most during muscle contraction

Question 3

What is the Osteotendinous Junction?

Answer 3

Tendon to Bone
(very strong)

Question 4

What is the Myotendinous Junction?

Answer 4

Muscle to Tendon
(prone to damage)

Question 5

Difference between Ligament and Tendon

Answer 5

Ligament: Bone to Bone
Tendon: Muscle to Bone

Question 6

What is Hyperplasia?

Answer 6

When a tissue or organ increase in size due to an increase in cell number

Question 7

Why can’t Skeletal Muscle undergo Hyperplasia?

Answer 7

Too long/big and have to many nuclei so can’t get organised to divide mitotically
(also do not get any more myocytes after birth)

Question 8

What is Hypertrophy?

Answer 8

Increase in muscle size due to increase in individual myocytes (cell size)
More myofibrils become packed into the muscle cell

Question 9

What do Anabolic Steriods do for Hypertrophy?

Answer 9

Increase protein synthesis through their interactions with specific target cells that include skeletal muscle and bone

Question 10

What are Anabolic Steroids?

Answer 10

Variants of testosterone that have been synthesised by pharmaceuticals

Question 11

What is Atrophy?

Answer 11

When the muscle decreases in size due to reduction of myofibrils in the myocytes
Happens when muscles are not stimulated by motor neurons.
The muscle becomes replaced by fat and connective tissue

Question 12

What is Hypoplasia?

Answer 12

Death of Myocytes
Hard to reverse

Question 13

What is the main function of Muscle?

Answer 13

Convert ATP into mechanical energy

Question 14

Describe Stability as a muscle function?

Answer 14

Helps stabilise joints with wide range of movement

Question 15

Describe Communication as a muscle function?

Answer 15

Facial Expression, Body Language, Writing/Speech

Question 16

Describe Control of “Body Passages and Openings” as a muscle function?

Answer 16

Sphincters (ring-like muscles) help control admission of light and food + drink (around mouth)
Elimination of waste via anal sphincters

Question 17

Describe Heat Production as a muscle function?

Answer 17

Produce 85% body heat
Used to maintain body temp

Question 18

What are Satellite Cells (Myoblasts)?

Answer 18

Only cells in muscle that can divide and fuse with each other + myocytes to REPAIR DAMAGE.
They sit underneath endomysium/basement membrane, but above sarcolemma.
Die off from old age

Question 19

How are Myoblasts formed?

Answer 19

During the formation of myocytes not all myoblasts fuse (they usually fuse to make a myocyte). Some remain as individual cells called satellite cells.

Question 20

What are Myostatin?

Answer 20

Turn of satellite cells

Question 21

Epimysium

Answer 21

Dense Irregular CT surrounding Perimysium and entire muscle

Question 22

Perimysium

Answer 22

Dense Irregular CT surrounding fascicles

Question 23

Fasicle

Answer 23

Bundle of Myocytes

Question 24

Endomysium

Answer 24

Loose Irregular CT surrounding myocytes. Contains nerves and capillaries that supply the myocytes.
Secreted by Fibroblasts

Question 25

Basement Membrane

Answer 25

Between myocyte and endomysium Thin, Specialised sheet of CT that surrounds muscle fibres and blends with endomysium

Question 26

Myocyte (Myofibre)

Answer 26

Bundle of Myofibrils Are multi-nucleated

Question 27

Sarcoplasm

Answer 27

Cell cytoplasm (liquid), area between myofibrils

Question 28

Sarcolemma

Answer 28

Cell memnrane

Question 29

Myoglobin

Answer 29

Protein inside Myocyte tthat binds and stores oxygen inside cells

Question 30

Myofibrils

Answer 30

Little muscle fibres in myocyte Many sarcomeres

Question 31

Sarcomere

Answer 31

Contractile unit Z disc (line in middle) A band (dark line) I band (light, shortens in contraction)

Question 32

Deep Fascia

Answer 32

Dense CT Surrounds bone, nerves, muscle , BV Highly vascularized Just under superficial fascia

Question 33

What is the order of outer tissue in the muscle?

Answer 33

Skin Superficial fascia Deep Fascia Deep Fascia blended with periosteum

Question 34

What investing fascia separates the compartments in the muscle?

Answer 34

Intermuscular Septa (bone to muscle) Interosseous membranes (bone to bone) Similar to deep fascia

Question 35

Muscle (Dorsiflexers)

Answer 35

Compartment Lifting foot up (synergist, assists the agonist muscle)

Question 36

Muscle (Planterflexers)

Answer 36

Compartment Agonist

Question 37

What is the main function of the three CTs?

Answer 37

epi, peri, endomysium Distribute forces generated by muscle fibre contraction

Question 38

What connects sarcomeres in a myofibril

Answer 38

Z lines

Question 39

What happens when all sarcomeres are stimulated in a myofibril?

Answer 39

Z-lines get pulled closer together, by filaments that make up the A + I Bands (sliding filament theory) Shortens the whole myofibril

Question 40

What happens when a myofibril is cut?

Answer 40

Can still contribute to contraction as individual myofibrils are connected to others via Desmin (protein) that attaches the z lines together Even if whole myocyte is cut, the contractions can be transferred up to the connective tissue

Question 41

Where are the protein complexes and what do they do?

Answer 41

Attach a myofibril to the sarcolemma Group of proteins form the protein complex . Helps to contribute to the strengthening of the sarcolemma while transmitting contractile forces generated by sarcomeres to the surrounding endomysium (above basement membrane)

Question 42

What does the Protein Complex contain?

Answer 42

Dystrophin can help with chemical signalling