Muscular System Flashcards
1
Q
What are the 3 types of muscles?
A
- cardiac striated muscle
- smooth muscle
- skeletal striated muscle
2
Q
Describe cardiac, striated muscles
A
- located in the heart
- pumps blood
- striated/striped
- involuntary (innervated via autonomic nervous system)
3
Q
Describe smooth muscles
A
- muscles located in organs and vessels
- unstriated/smooth
- involuntary (innervated via autonomic nervous system)
4
Q
Describe skeletal muscles
A
- move body parts
- striated
- voluntary (innervated via somatic nervous sytem)
5
Q
What are the 3 connective tissue sheaths? (superficial to deep)
A
- epimysium
- perimysium
- endomysium
6
Q
What does the epimysium surround?
A
entire muscle (contains the perimysium & endomysium)
7
Q
What does the perimysium surround?
A
- group of muscle fibers (fascicle/fiber bundle)
- holds all the fiber bundles together
8
Q
What does the endomysium surround?
A
individual muscle fiber
9
Q
What is the sarcolemma?
A
- cell membrane of the muscle fiber
10
Q
What is a muscle fiber?
A
- structural unit of a muscle
- contains multiple myofibrils
11
Q
What is a myofibril?
A
- contractile elements of a muscle fiber
- contains multiple sarcomeres
12
Q
What is a sarcomere?
A
- functional contractile unit within a muscle
- contains actin and myosin
- surrounded by endomysium
13
Q
What is a motor unit?
A
- functional unit of a muscle
- consists of motor neuron & muscle fibers it controls
14
Q
What is the musculotendinous unit?
A
- 2 components
1. contractile muscles (muscle belly made of skeletal, striated muscle)
2. non-contractile structures (tendons and aponeuroses)
15
Q
What is the function of a muscle?
A
- produce movement
- provide static support
- helps shape body
- provides heat
16
Q
What is an aponeurosis?
A
sheath of connective tissue that connects muscles to bones
17
Q
What type of tissues do skeletal muscles attach to?
A
- bone
- cartilage
- ligaments
18
Q
How do skeletal muscles connect to bone, cartilage, or ligaments?
A
- tendons
- aponeurosis
- organ (eyeball, skin, mucous membrane)
19
Q
How are muscles named?
A
- points of attachments
- length
- shape
- size
position - number heads
20
Q
What is an example of a muscle named based on the point of attachment?
A
sternocleidomastoid (attaches to sternum, clavicle, and mastoid)
21
Q
What is an example of muscles named based on their length?
A
- flexor pollicis longus (long)
- flexor pollicis brevis (short)
22
Q
What is an example of a muscle based on their shape/size?
A
gluteus maximus
23
Q
What is an example of a muscle based on its position?
A
- flexor digitorum superficialis (superficial)
- flexor digitorum profundus (deep)
24
Q
What is an example of a muscle based on its number of heads?
A
- triceps
- biceps
25
What are the different classifications of muscles?
1. pennate
2. fusiform
3. flat
4. convergent
5. circular
26
Describe a pennate muscle
- many short, featherlike fibers attached to the tendon
- produces greater strength due to extra fibers
- ex: deltoid
27
What are the types of pennate muscles?
- unipennate
- bipennate
- multipennate
28
Describe a unipennate muscle
featherlike fibers on 1 side of the tendon
29
Describe a bipennate muscle
featherlike fibers on two sides of the tendon
30
Describe a multi-pennate muscle
featherlike fibers on two sides of multiple tendons that combine to make 1 muscle
31
Describe a fusiform muscle
- spindle shape muscle
- produces greater range of muscle
- muscle has tendons on either side of it
- ex: biceps (tendon, belly of muscle, tendon)
32
Describe a flat muscle
- muscle fibers are parallel with an aponeurosis
- ex: external oblique
33
Describe a convergent muscle
- fan shaped muscle
- broad attachment that converges to a tendon
- ex: pectoralis major
34
Describe a circular muscle
- circles around an opening
- constricts the opening when the muscle contracts
- ex: orbicularis oculi (around the eyes)
35
How much can a muscle contract?
Up to **70% of its length**
36
What is a muscle origin?
- proximal attachment end of the muscle
- fixed part of muscle
37
What is the muscle insertion?
- distal attachment end of the muscle
- moves toward the origin/proximal part of the body
38
What are the 3 types of muscle contractions?
1. reflexive contraction
2. tonic contraction
3. phasic contraction
39
Describe a reflexive contractraction
- automatic
- no voluntary control
- ex: diaphragm
40
Describe a tonic contraction
- slight contraction (aka muscle tone)
- muscle contracts but no movement of the body is produced
- when contracted, you cannot physically see the muscle move
- assists with joint stabilization & posture
41
What are the types of phasic contractions?
1. isometric
2. isotonic
42
What is isometric contraction?
- contraction of muscle
- no movement is produced
- no change of muscle length
43
What is isotonic contraction?
- contraction of muscle
- produces movement
- lengthening & shortening of muscle
- 2 types
44
What are the types of isotonic contraction?
1. concentric
2. eccentric
45
What is a concentric contraction?
- shortening of muscles
- movement goes **against** gravity for occupational activities
- movement in the horizontal plane
- movements go **with** gravity in a **fast** movement
46
What is an eccentric contraction?
- **slow** movements going **with** gravity
- muscle acts as a brake
47
What type of muscle contractions do OTs focus on?
phasic contractions (isotonic/isometric)
48
What type of muscle contraction can a patient post-surgery do?
isometaric (no movement is produced)
49
What are different roles of the muscle?
- prime mover (agonist)
- fixator
- neutralizer
- synergist
- antagonist
50
What is a prime mover (agonist)?
muscle creating the primary movement
51
What is a fixator?
- fixates the joint proximal (closest to the body) to the joint that is moving
- allows for isolated movement
- ex: muscles fixate the elbow to allow wrist movement
52
What is a neutralizer?
- cancels out the action of a muscle at a biaxial or triaxial joint
- allows prime mover to isolate the movement
53
What is a synergist?
- assistive mover
- complements the prime mover
54
What is an antagonist?
- muscle that relaxes to allow the prime mover to contract
- opposite of prime mover
55
What occurs to the muscles to a person with Parkinson's?
prime mover AND the antagonist contract
56
What is Manual Muscle Testing?
- used to assess muscle strength
- grading scale from 0-5
57
What are the different ratings for the Manual Muscle Test?
- 1: muscle contraction occurs with no movement
- 2: cannot move against gravity but they can move in a gravity eliminated plane
- 3: normal range of motion against gravity
- 4: patient can apply moderate resistance
- 5: patient can contract their muscle against maximum resistance
58
What is an electromyography (EMG)?
uses surface electrodes to determine muscle activity
59
What is muscle atrophy?
- complication that can occur due to a nerve injury
- includes spinal cord injury & primary disorder to the muscle or long term disuse
60
Why is muscle atrophy so bad?
- you cannot **add** muscle fibers (only strengthen)
- once a muscle atrophies, you cannot regenerate the muscle
- try to catch muscles early before they atrophy
