MYOLOGY

Question 1

Muscle Characteristics

4 characteristics of mucsles

Answer 1

1. excitability:
- respond to stimulus
2. contractility
- shorten + gen force
**3. extensability **
- can be stretched
4. elasticitity
- return to its original length

Question 2

Muscle Types

3 types of muscle tissue

Answer 2

1. smooth
2. cardiac
3. skeletal

Question 3

Muscle types

Characteristics of smooth muscle

Answer 3

• non-striated
• involuntary

Question 4

Muscle types

Characteristics of cardiac muscle

Answer 4

• straited
• involuntary

Question 5

Muscle types

Characteristics of skeletal muscle

Answer 5

• striated
• involuntary

Question 6

Skeletal muscle

Label the skeletal muscle
What is it function?

Answer 6

Structure:
1. muscle organ
2. fasicle / bundle of myofibres
3. myofibre (muscle cell)
4. myofibril
5. myofilaments (actin and myosin)

Function:
- contractile cells -> where ‘work’ occurs

Question 7

Skeletal Muscle

Function of muscle attachment points

Answer 7

- Proximal attachment: least mobile bone
- Distal attachment: most mobile bone

Question 8

Skeletal Muscle

Structure and function of CT w in skeletal muscle

Answer 8

1. perimysium:
- surrounds each fasicle (bundle of musc fibres)
2. endomysium:
- surrounds each muscle fibre
3. epimysium/fascia:
- surrounds entire muscle

Question 9

Skeletal muscle

Action

movement produced when muscle contracts _____ in isolation eg.

depends on which 3 things?

Answer 9

• movement produced when muscle contracts concentrically in isolation eg. ext/flex, abd/add, rotation

depends on:
- site of attach
- type of joint
- line of pull to the joint

Question 10

Muscle Belly structure

Structure and function of the fasicle

Answer 10

structure:
- (bundle of musc fibres)
- perimysium
- endomysium
- epimysium
function:
- force production

Question 11

Muscle tissue

Structure and function of the 4 types of muscle tissues

Answer 11

**1. muscle cells/fibres: **
- do the work
2. capillary network:
- rich blood supply -> rapid deliv of nutr + remove wastes
3. nerve supply:
- stimulates musc -> contract
4. fibrous connective tissue:
- consists of perimysium, epimysium, endomysium

Question 12

Skeletal muscle attachments

3 types of skeletal muscle attachments

Answer 12

1. fleshy
2. tendon
3. raphe

Question 13

Skeletal muscle attahcments

Structure and function of Raphe

eg. obliques

Answer 13

Structure:
- musc fibres attach to a CT sheet -> connects to bone
**Function: **
- DCR frict, distrib force

eg. obliques

Question 14

Skeletal muscle attahcments

Structure and function of Tendon

eg, semitendinosus

Answer 14

Structure:
- musc fibres connect to a cord-like tendon -> connect to bone
Function:
- DCR frict, distr force

eg, semitendinosus

Question 15

Skeletal muscle attahcments

Structure and function of Fleshy

eg, glute max

Answer 15

**Structure: **
- musc fibres attach directly to bone w min CT
**Function: **
- prov stable force transmission

eg. glute max

Question 16

Myofibres (msucle cells)

Structure and function of myofibres

Answer 16

structure:
- Actin (thin) & myosin (thick) filaments slide over one another
function:
- product muscle shortening

Question 17

Sliding Filament Theory

Steps
1. muscle shortening
2. formation of CBs
3. power stroke
4. release + reset
5. repeat cycles

Answer 17

Step 1- muscle shortening
- Actin and myosin filaments slide over each other, causing the sarcomeres to shorten, which leads to muscle contraction

Step 2 - Formation of Cross-bridges
- myosin attach to actin
- **CB’s ** formed

Step 3 - Power Stroke
- myosin (thick) heads pivot, pulling the actin filaments toward the center of the sarcomere, which causes the muscle to contract

Step 4 - Release and Reset
- ATP binds to the myosin (thick) head, causing it to detach from the actin (thin). The myosin head then resets to its original position, ready for the next cycle.

Step 5 - Repeated Cycles
- as long as calcium ions are present and ATP is available, the process repeats, causing continuous contraction.

Question 18

Classifiying skeletal muscle fibre oritenations

structure and function of Parallel fibres

fibres run in a ____ line bw attachments

Answer 18

structure:
- fibres run in a straight line between attachments
- long and flat

function:
- shorten muscle belly (up to 50%)
- greater ROM but LESS force

Question 19

Classifiying skeletal muscle fibre oritenations

structure and function of Oblique fibres

Answer 19

structure:
- fibres run on an angle between attachments
function:
- less shortening of musc belly
- less ROM but MORE force

Question 20

Classifiying skeletal muscle fibre oritenations

structure and function of circular fibres

Answer 20

structure:
- fibres run around an opening
function:
- contraction of narrow openings

Question 21

Classifiying skeletal muscle fibre oritenations

Egs of parallel skeletal msucles

Answer 21

• flat/quadrilateral eg. quadratus femoris
• strap eg. sartorius
• triangular eg. pirifemoris
• fusiform eg. bicep

Question 22

Classifiying skeletal muscle fibre oritenations

Egs of oblique skeletal msucles

Answer 22

• unipennate eg. flexor pollicius longus
• bipennate eg. rectus femoris
• multipennate eg. deltiod

Question 23

Classifiying skeletal muscle fibre oritenations

Egs of circular skeletal msucles

Answer 23

• circular muscle eg. sphincters

Question 24

Skeletal muscle contractions

Isometric contraction

Answer 24

• musc gen force without changing its length, meaning there’s no movement at the joint.
• eg. plank

Question 25

# Skeletal muscle contractions Isotonic contraction

Answer 25

- musc **changes its length while generating force,** causing **movement** at the joint. There are two types of isotonic contractions: **Concentric contraction:** - The muscle **shortens** as it contracts (e.g., lifting a weight). **Eccentric contraction: ** The muscle **lengthens** while contracting (e.g., lowering a weight).

Question 26

# Muscle roles Agonist

Answer 26

- muscle that **contracts** and generates **force**. Example: In a bicep curl, the biceps are the agonist.

Question 27

# Muscle rolls Antagonist

Answer 27

- muscle that opposes the agonsit - it **relaxes** to let the agonist move and controls the movement. Example: In a bicep curl, the triceps are the antagonist.

Question 28

# Muscle rolls Stabiliser/Fixator

Answer 28

- muscles that **stabilse** one part of the body while **another part moves** - Example: In a push-up, the core muscles stabilize the body.

Question 29

# Muscle rolls Neutraliser

Answer 29

- muscle that **stops** **unwanted** **movement** during an action. Example: In a shoulder press, the posterior deltoid helps prevent shoulder rotation.

Question 30

What happens when a muscle crosses 2 joints? | active and passive insufficiency

Answer 30

- *limit ROM and force production.* **Active insufficiency:** - when the muscle is **too short** to generate full force across both joints. **Passive insufficiency:** - when the muscle is **too stretched **to allow full ROM.

Question 31

# Biomechanics 1st Class Lever | 1- EL

Answer 31

- The fulcrum is between the ***effort*** and ***load***. Example: Neck movement (fulcrum = atlas, effort = neck muscles, load = head).** - Balance

Question 32

# Biomechanics 2nd Class Lever | 2 - FE

Answer 32

- The load is between the ***fulcrum*** and ***effort***. Example: Standing on tiptoe (fulcrum = ball of foot, load = body weight, effort = calf muscles).** - force/heavy loads

Question 33

# Biomechanics 3rd Class Lever | 3 - FL

Answer 33

- The effort is between the ***fulcrum*** and ***load***. Example: Bicep curl (fulcrum = elbow, effort = biceps, load = hand weight). - Speed and range of motion but requires more effort.

Question 34

Classifying muscles | 6 things

Answer 34

- size - shape - location - attachment - action - no. of heads

Question 35

Length - tension r/ship

Answer 35

- tension a muscle fibre can produce vs the length of a sarcomere

Question 36

# Accessory structures of Skeletal muscles Structure and function of bursae

Answer 36

**structure:** - sacs of syn membrane containing syn fluid **function:** - allow muscles to slide over other struct w out frict

Question 37

# Accessory structures of skeletal muscles Structure, function and location of tendon sheaths

Answer 37

**structure:** - contain synovial fluid -> lubrication **function:** - DCR friction - help tend transmit force - keep tendons att to bone dur movem **location:** - distal ends of limbs

Question 38

# Accessory structures of skeletal muscles Structure and function TFL

Answer 38

**structure:** - dense firbous CT surrounding muscles of the thigh **function:** - venous return - knee stability

Question 39

# Accessory structures of skeletal muscles Structure and function of iliotibial tract

Answer 39

**structure:** - band of CT - continuation of TFL **function:** - flex + abd - knee stabilisation **location:** - distal ends of limbs

Question 40

Functional roles of muscles that move the hip

Answer 40

- hip flexors: lifting leg/drive movem - glute musc: hip ext