functional anatomy

Question 1

fusiform

Answer 1

fibers run longitudinally from a tendon. Can shorten over large range but not very strong

Question 2

penniform

Answer 2

fibers that run at an angle from the tendon (unipennate, bipennate, multipennate. Produce more force but not as quick.

Question 3

Epimysium

Answer 3

muscles are in a thin layer of connective tissue call epimysium

Question 4

fasciculi

Answer 4

inside the epimysium are bundles of muscle fibers caller fasciculi

Question 5

sarcolemma

Answer 5

each muscles fiber is encased by a thin membrane called sarcolemma

Question 6

myofibrils

Answer 6

each muscles is made up of a bundle of 100s of myofibrils

Question 7

sarcoplasm

Answer 7

is a gel like structure between the myofibrils which contains mitochondria, fat, gylcogen, ATP ect…

Question 8

sarcomere

Answer 8

each myofibril is the length of a muscle fiber and contains many sarcomeres, which is the basic contractile unit of the muscle.

Question 9

sliding filament (explanation)

Answer 9

1. when there is a neuromuscluar stimulation, calcium is released into the sacroplasmic reticulm
2. this prompts binding sites on the actin to be exposed, so that myosin heads can attach (cross bridges)
3. with the use of ATP the myosin heads contract and pull/slide the actin filaments across the myosin filaments
4. the actin filaments are pulled towards each other (when totally contracted actin and myosin filaments will overlap causing the I bands and H zones to disapear)

Question 10

what impacts the amount of force being produced?

Answer 10

the amount of force generated by the muscle depends on the number of myosin cross-bridges attaching to actin.

Question 11

characteristics of type I

Answer 11

slow twitch
slow to fatigue
contract slowly
best for aerobic work
red in colour

Question 12

type IIa

Answer 12

can sustain for long period Or;
can burst with force then fatigue
white in colour
intermediate fast twitch

Question 13

type IIb

Answer 13

contract quickly and powerfully
tire quickly
best for speed and strength (anaerobic)
fast twitch 
white in colour
restiance to fatigue low 
cp levels high
motor unit size large 
capaliery density low
mitacondrah density low

Question 14

force-velocity (concentric)

Answer 14

maximum force is achieved when a muscle contracts at a low velocity
As velocity of contraction increases, the force generated decreases

Question 15

force-velocity (eccentric)

Answer 15

max force is achieved at max velocity

as velocity of contraction increases force generated increases

Question 16

force-length relationship

Answer 16

the amount of force that can be produced by a muscle is also related to the length at which the muscle is held.

Question 17

max force (length)

Answer 17

80% and 120% of resting length

Question 18

shorten/lengthen

Answer 18

shorten are max overlapped and lengthen to much space in between creating a slippage in cross bridge

Question 19

structure a neuron (dentrites)

Answer 19

receives impulse/stimulus from the spinal cord and sends it to the cell body

Question 20

structure a neuron (cell body)

Answer 20

processes and directs the impulse to the axon and along the axons length

Question 21

structure a neuron (axon)

Answer 21

delivers the impulse along its length to the end of the axon (axon terminal) to the end motor plates where they stimulate the muscle fibres

Question 22

central nervous system (brain)

Answer 22

1. analyses the info recieved from the sensory neuron
2. determines the most suitable response
3. sends impulses to the targeted muscles via the spinal cord and peripheral nerves

Question 23

central nervous system (spinal cord)

Answer 23

1. delivers sensory messages from the brain to the body

2. delivers motor messages (movement) from the brain to the body (muscles)

Question 24

the peripheral nervous system

Answer 24

is made up of sensory and motor neurons which transmit messages to and from the central nervous system

Question 25

sensory/motor division

Answer 25

sensory: carries singals from the receptors to the CNS
motor: carries signals from the CNS to the muscles

Question 26

components of a motor unit

Answer 26

comprises of a motor neuron and the muscle fibres

a whole muscle has many many motor units which allow the muscle to generate different types of force

Question 27

neuromusular junction

Answer 27

the area between the axon terminal and neurons and muscle fibres

Question 28

recognition of a stimulus

Answer 28

1. when we recognize a stimulus using our senses, a sensory neuron sends an impulse to the central nervous system
2. the brain will acknowledge the stimulus and decides what movement is necessary for that situation
3. our brain then sends an impulse down the spinal cord to the relevant motor neurons
4. the motor neuron will send a message to their associated muscle fibre to contract

Question 29

innervating a muscle fibre (action potential)

Answer 29

the electrical impulse that travels from the cell body to the neuromuscular junction is called the action potential

Question 30

innervating muscle fibres (what happens when action potential reaches the required threshold)

Answer 30

a neurotransmitter is released from the neuron and passes across the neuromusclar junction

Question 31

innervating muscle fibres (The neurotransmitter for muscle contraction is?)

Answer 31

acetylcholine

Question 32

innervating muscle fibres (Acetylcholine binds to?)

Answer 32

the acetycholine receptors on the muscle fibres. this allows sodium into the muscles and potassium out creating a positive charge

Question 33

innervating muscle fibres (what happens to the positive charge?)

Answer 33

spreads across muscle fibres, which triggers a release of calcium from the sacroplasmic reticulm. then contracts

Question 34

innervating muscle fibres (if not stimulated again?)

Answer 34

calcium ions are drawn back into the sacroplasmic reticulm and the muscle returns back to OG.

Question 35

preferential motor unit recruitment

Answer 35

motor units are recruited in a given order depending on exercise intensity