Chapter 7- Muscular system Flashcards
What is the primary and secondary functions of the muscular system
primary: move skeleton
secondary: heat production
What are the two types of muscle tissue?
smooth muscle
cardiac muscle
skeletal muscle tissue is made up of what kind of muscle cells?
myocytes
muscle fibers
how are muscles anchored to bones?
tendons, which can be rope like or flat (aponeurosis)
describe how tendons bind to bones
its made up of fibrous tissues and merges with the fascia that covers the muscles and with the perisoterum (fibrous connective tissue) that covers the bone.
on average how many tendons per muscle, and what are they called?
2, each attaching to different bones.
the immobile attachment to the muscle is called origin, the more movable attachment is called insertion.
what are the two general types of muscle arrangements?
opposing > antagonist or antagonistic muscle
cooperative > synergists or synergistic muscle
define how muscles work in an antagonistic arrangement and how the tendons are involved in the movement (use the arm as an example)
tendons origin located on scapular the insertion tendon is located on the radius/ulna (forearm bone).
The biceps contract and flexes the forearm, when they relax the tricep contracts and pulls(extends) the forearm to straighten the elbow.
what is the purpose of Range-Of-Motion exercises?
designed to stretch and contract the antagonist muscles of a joint to preserve as much muscle function and joint mobility as possible.
What are synergistic muscles?
muscles that have the same function/work together to perform a particular function.
- can also refer to muscles that help stabilize or steady a joint to make more precise movements.
Give an example of a synergistic muscle using the bicep example.
muscle is called brachialis muscle.
palm up = bicep does work
thumb up- shared work
palm down- brahialis does the work
what is a “primary mover” in terms of muscle movement?
primary movement using basic anatogistic muscles. Think natural movement using biggest and strongest muscles for that movement.
How does the brain coordinate movement?
nerve impulse originates from frontal lobe of cerebrum. motor areas generate electrochemical impulses that travel through muscle neurons to muscle fibres, causing them to contract.
whats a motor unit?
when a single axon of a motor neuron may branch extensively, and therefore innervates +++ muscle fibres.
what is muscle coordination and what part of the brain regulates this action?
the action of many muscles working together contracting and relaxing to make smooth and efficient movements. ie: walking, and dancing.
its regulated by the cerebellum
what is muscle tone?
the theory that all muscles are in a slight state of contraction except when asleep
what improves coordination?
good muscle tone through exercise.
Generally what are the two types of exercises genres you can perform?
isotonic exercise: muscle contracts and bring about movement. will produce tone, and strength via aeorbic work.
isometric exercise: contraction without movement > will produce tone and strength by not aeorbic
what is aerobic exercise?
isotonic exercise performed for 30 mins or more, and it strengthens the heart and respiratory muscles as well as muscles attached to the skeleton.
what are the two types of isotonic contractions?
- concentric contractions: shortening of the muscle as it exerts force
- eccentric contractions: lengthening of a muscle as it still exerts force.
Give examples of isotonic and isometric exercises.
picking up a pencil: isotonic
holding the pencil: isometric
pulling a door open= isotonic
holding door open= isometric
What is the striated muscle?
newly discovered, and is an endocrine tissue, that excretes Irisin during exercise. This hormone affects adipose tissue and converts white adipocytes to brown adipocytes.
What is muscle sense (proprioception)?
the brains ability to known where our muscles are and what they are doing without our having to look at them and be aware of them.
within muscle cells are stretch receptors. what do they do?
detect changes in the length of a muscle as it stretched, they generate an impulse to the brain to let it know where the muscle is.
What are anabolic steroids?
synthetic drugs similar in structure and action to the male hormone testosterone.
What provides energy for muscles to contract?
#1 ATP > not stored in abundance #2 creatine phosphate > used to synthesize more ATP #3 glycogen > most abundant energy source, breaks into glucose then into ATP, heat is a byproduct.
what is myoglobin
protein in muscle cells that store some oxygen within the cell. They also contain iron- give muscle its dark colour.
* quickly used up during strenuous exercise.
what is oxygen debt?
when the muscle fibres run out of stored up oxygen. When this happens the cell respiratory process becomes anaerobic and glucose is converted to lactic acid which contributes to muscle fatigue and pain (cramps)
Describe a muscle fibre
has its own motor nerve ending called neuromuscular junction
axon terminal is the enlarged tip of the motor neuron and it contains the sac of the neurotransmitter acetylcholine.
membrane of muscle fibre is sarcolemma, contains the receptor sites for acetylcholine and an inactivator called cholinesterase. The synapse is the small space between axon terminal and sarcolemma.
in the fibre theres contracting unites called sarcomeres, arranged in cylinders call myofibrils.
surrounding sarcomeres are sarcoplasmic reticules (Ca+ reserve)
What are the proteins involved in muscle fibre movements?
myosin, actin (contractual fibres)
titin (anchor protein)
troposin and tropomyosin (inhibitor proteins)
Describe the axon terminal of the neuromuscular junction
end of a motor neuron; contains vesicles of acetylcholine and are opened by arrive of nerve impulse
Describe the sarcolemma of the neuromuscular junction
cell membrane of the muscle fibre
It has receptors for acetylcholine
Describe the synaptic cleft of the neuromuscular junction
space between the axon terminal and the sarcolemma
Describe the acetylcholine receptors of the neuromuscular junction
origins of the sarcolemma that are channels for Na+ ions, are opened by Acetylcholine
Describe the acetylcholine (Ach) of the neuromuscular junction
neurotransmitter released by the axon terminal; diffuses across the synaptic cleft bonds to the ACh receptors and brings about depolarization of the sarcolemma with an influx of Na+ ions
Describe cholinesterase-receptors of the neuromuscular junction
the enzyme that inactivates acetylcholine; prevents continued depolarization and contraction.
Describe the polarization of a muscle fibre
relaxed muscle = polarized sarcolemma.
polarization = Na+ outside cell and K+ inside the cell. [] maintained from sodium and potassium pumps.
depolarization caused by ^ of acetylcholine from neuron impulse. ACh receptors make cells permutable to Na+ ions. Ions rush into the cell and the fibre becomes depolarized, the electric pulse generates active potential then passes along muscle fibre, via T tubles.
repolarization completes the action potential and K+ ions are outflown from cell.
what is the term given to nerve impulses that arrive in a continuous stream and produce a sustained contraction?
tetanus
- muscle fibres remain contracted and are capable of effective movements.
when nerves don’t receive impulses they become paralyzed. What happens to the paralyzed muscles?
they eventually become atrophic (become small d/t lack of use)
what happens to muscles as they age?
die and are replaced with fibrous tissue and fat.
loss of muscle fibres contributes to loss of propricepton which leads to unsteadiness
what helps prevent atrophy of muscles?
exercise, by maintaining muscle function.
what is neurotoxin
a chemical that disrupts the normal functioning of the nervous system.
what is Tetanus? (disease)
the inability of muscles to relax. the toxin is produced by the tetanus bacteria and affects nervous system in a way that muscles fibres get to many signals and spasms.
what is Botulism?
type of food poisoning - without typical characteristics,
froma bacteria and inhibits the release of ACh. Muscles become paralyzed.
what is muscle dystrophy?
a group of genetic disease in which muscle tissue is replaced by fibrous connective tissue or by fat.
- neither tissue can contract and therefore muscle function is loss.
Whats the most common form of muscle dystrophy?
Duchenne’s muscular dystrophy
skeletal muscle and cardiac muscles are affected.
Age 2-5, Sex linked X train. this affects the production of protein Dystrophin - needed for stability of sarcolemma and ion movement.
What is Myasthenia gravis?
autoimmune disorder characterized by extreme muscle fatigue.
autoantibodies destroy the acetylcholine receptors on the sarcolemma.
What is the action Flexion
decrease the angle of a joint
What is the action extension
increase the angle of a joint
What is the action adduction
move closer to the midline
What is the action abduction
to move away from the midline
What is the action pronation
to turn the palm down
What is the action suprination
to turn the palm up
What is the action dorsiflexion
to elevate the foot
What is the action plantar flexion
to lower the foot
What is the action inversion
to move the sole of the foot medially at the ankle
What is the action eversion
to move the sole of the foot laterally at the ankle
What is the action rotation
to move a bone around its longitudinal axis
intramuscular injections are used when repod absorption is needed. Where and why is this done?
muscle has a good blood suply, safest spot is considered the gluteus medius muscle. Alternative sites: vastus lateralis (thigh), deltoid muscle (shoulder)
