Muscular system

Question 1

Name the 3 types of muscle tissue and whether each is striated or not.

Answer 1

SCS

1. Skeletal - striated
   Attaches to bones by tendons
2. Cardiac - striated
   Heart wall
3. Smooth - not striated
   In walls of hollow structures, e.g. intestines

Question 2

Two functions of muscle tissue

Answer 2

1. produce body movement
2. Stablise body positions
3. Move substances within body
4. produce heat

Question 3

List and describe the 5 properties of muscle tissue

Answer 3

1. excitability - can respond to chemicals
2. conductivity - propagate electrical signals across plasma membrane
3. contractility - able to contract
4. extensibility - ability to stretch without damaging tissue
5. elasticity - return to original shape after stretching

CCEEE

Question 4

Name the connective tissue coverings on a muscle (one main one and then 3 extending from that one)

Answer 4

Fascia

Epimysium - outer layer encircling entire muscle, dense irregular CT

Perimysium - bundle large groups of muscle fibres, dense irregular CT

Endomysium - separates individual muscle fibres from each other, reticular fibres

Question 5

MUSCLE FIBRE CELL COMPONENTS

Sacolemma

Answer 5

Plasma membrane

Question 6

MUSCLE FIBRE CELL COMPONENTS

Transverse tubule

Answer 6

Through sarcolemma into centre of each muscle cell

Question 7

MUSCLE FIBRE CELL COMPONENTS

Sarcoplasm

Answer 7

Cytoplasm of muscle cell

Myoglobin and glycogen

Release oxygen when needed by mitochondria for ATP production

Question 8

MUSCLE FIBRE CELL COMPONENTS

Sacroplasmic reticulum

Answer 8

Fluid-filled system of membraneous sacs; encircle each myofibril

Stores calcium, triggers muscle contraction by releasing Ca2+

Question 9

MUSCLE FIBRE CELL COMPONENTS

Myofibrils + 3 types of proteins

Answer 9

Small, thread-like proteins in the sarcoplasm

Contractile organelles

1. Contractile protein - generate force during contraction
2. regulatory protein - help switch contraction processes on and off
3. structural protein

Question 10

MUSCLE FIBRE CELL COMPONENTS

Myofilaments

Answer 10

Compartments

Question 11

What is the contraction cycle?

Answer 11

Repeating sequence of events that result in contraction of muscle

Question 12

Describe the 4 steps of the contraction cycle

Answer 12

1. ATP hydrolysis - ATP hydrolysised into ADP
2. Cross bridges formed - attachment of myosin to actin
3. Power stroke - Sliding
4. Detachment of myosin from actin

Question 13

Name the 3 ways to produce ATP for muscle contraction

Answer 13

Creatine phosphate - max 15 seconds (sprint)

Anaerobic glycolysis - max 2 mins (200m sprint)

Aerobic respiration - more than 10mins (marathon)

CAA

Question 14

What is a motor unit?

Answer 14

1 somatic motor neuron + all skeletal muscles it stimulates

Question 15

What factors impact the strength of a muscle contraction?

Answer 15

Size of motor unit and number activated

Question 16

What is a twitch contraction?

Answer 16

Brief contraction of all muscle fibres in a motor unit in response to a single muscle action potential

Question 17

Describe what happens in the contraction and relaxation period

Answer 17

Contraction period: Ca2+ binds to troponin; myosin binding sites on actin are exposed and cross bridges form; peak tension develops

Relaxation period: Ca2+ is actively transported back into the SR; myosin heads detach from actin; tension in muscle decreases

Question 18

What is muscle tone?

Answer 18

Involuntary, weak contraction of a small number of motor units that are alternatively shifting between active and inactive

Question 19

What happens to tension and muscle length in isometric, concentric and eccentric contractions?

Answer 19

Isometric: constant tension and muscle length

Concentric: Shorten length, increase tension

Eccentric: Lengthen and increase tension

Question 20

Name 3 skeletal muscle types

Answer 20

Slow oxidative

Fast oxidative

Fast glycolytic

Question 21

For each of the 3 skeletal muscle types (Slow oxidative, Fast oxidative, Fast glycolytic) describe:

structure
method of producing ATP
primary function
location

Answer 21

Slow oxidative: many mitochondria and capillaries; red; aerobic respiration (high); postural muscles, e.g. neck; maintain posture and aerobic endurance

Fast oxidative: many mitochondria and capillaries; red-pink; aerobic respiration and anaerobic glycosis; lower limb muscles; walking/sprinting

Fast glycolytic: Few mitochondria and capillaries; white (pale); anaerobic glycolysis; upper limb muscles; rapid/intense movements of short duration

Question 22

What is the attachment of a muscle’s tendon to the stationary bone called?

Answer 22

Origin

Question 23

What is the attachment of a muscle’s tendon to the moveable bone called?

Answer 23

insertion

Question 24

What is the fleshy portion of the muscle between attachment sites called?

Answer 24

Belly

Question 25

What are the 3 components of a lever?

Answer 25

Load (resistance), fulcrum (fixed point, joint where insertion is) and effort (force - muscle/strength)

Question 26

Name the 3 classes of lever

Answer 26

1st class - EFL (effort, fulcrum, load) 2nd class - ELF 3rd class - FEL

Question 27

For 1st class levers, give an example in the body including the joints and movements involved.

Answer 27

Head resting on vertebral column Effort: Posterior neck muscles contract Fulcrum: Joint between atlas and occipital bone Load: Weight of anterior portion of the skull

Question 28

For 2nd class levers, give an example in the body including the joints and movements involved.

Answer 28

Standing on your toes Effort: contraction of calf muscles Load: weight of the body Fulcrum: ball of foot

Question 29

For 3rd class levers, give an example in the body including the joints and movements involved.

Answer 29

Flexing forearm at elbow Fulcrum: elbow Effort: weight of hand and forearm Load: contraction of biceps branchii

Question 30

Name the 4 muscle groups when it comes to coordination of the muscles

Answer 30

Prime mover (agonist): contract to cause an action Prime mover (antagonist): relax Synergist: two muscles work together to do an action Fixator: stabilise the origin of the prime mover

Question 31

For biceps branchii, name the number of origins, location in body, and which movement and action it contributes to

Answer 31

Origin: 2 Location: upper arm Movement and action: flexion of forearm, flexion and adduction of whole arm

Question 32

For triceps branchii, name the number of origins, location in body, and which movement and action it contributes to

Answer 32

Origins: 3 Location: upper arm Movement and action: extension of the forearm

Question 33

For rectus femoris, name the number of origins, location in body, and which movement and action it contributes to

Answer 33

Origin: 2 Location: Thigh (upper leg) Action: Thigh flexion and leg extension

Question 34

For sternocleidomastoid, name the number of origins, location in body, and which movement and action it contributes to

Answer 34

Origin: 1 (sternum) Insertion: clavicle Mastoid: back of the head Action: rotation of head and flexion of neck

Question 35

Name 3 characteristics by which skeletal bones are named

Answer 35

Number of origins (e.g. bicep) Size (e.g. maximus) Shape (e.g. deltoid)