Muscles Flashcards
0
Q
Special characteristics of muscle tissue
A
- excitability
- Contractility
- Extensibility
- Elasticity
1
Q
4 functions of muscle
A
- Produces movement
- Maintains posture
- Stabilizes Joints
- Generates heat
2
Q
Excitability
A
Also called responsiveness, ability to receive and respond to stimulus
3
Q
Contractility
A
Ability to shorten forcibly, sets muscle apart from other tissue types
4
Q
Extensibility
A
Ability to extend or stretch
5
Q
Elasticity
A
Ability of muscle cell to recoil and resume it’s resting length after stretching
6
Q
3 types of muscle tissues and there similarities and differences
A
- Skeletal muscle: cells called muscle fibers, have striations, voluntary
- Cardiac muscle: striated, involuntary
- Smooth muscle: no striations, visceral, involuntary
7
Q
Name of the plasma membrane of a muscle cell
A
Sarcolemma (muscle husk)
8
Q
Muscle cell cytoplasm
A
Sarcoplasm
9
Q
Connective tissue sheaths of a muscle
A
- Epimysium
- Perimysium and fascicles
- Endomysium
10
Q
Epimysium
A
Overcoat of DICT surrounding the whole muscle
11
Q
Perimysium
A
Surrounds each fascicle, made of fibrous connective tissue
12
Q
Endomysium
A
CT that surrounds each muscle fiber
13
Q
Parts of a muscle
A
- epimysium
- Perimysium
- Endomysium
- Tendons
- Fascicles
- Nerves and blood vessels in the muscle
14
Q
When a muscle contracts, the movable bone
A
The insertion moves towards the orgin
15
Q
Insertion
A
Movable part of the muscle
16
Q
Origin
A
Less movable part of the muscle
17
Q
Direct attachment
A
(Fleshy attachment) the epimysium of the muscle is fused with a periosteum or perichondrium
18
Q
Indirect attachment
A
Extends bruin muscle as a tendon or aponeurosis
19
Q
Aponeurosis
A
Sheet like ct that connects muscles to a bone, cartilage or other muscles
20
Q
Why are muscle fibers multinucleate?
A
The muscle cells fuse together
21
Q
Myofibrils
A
Individual fiber in the muscle cell made up of sarcomeres
22
Q
A bands
A
A dark band on a myofibril
23
Q
I band
A
Light band on a myofibril
24
Saracomere
The smallest contractile unit of a muscle, myofibril a are made up of sarcomeres. A sarcomere is a section of a myofibril
25
Organizational and structure level of a muscle from organ to molecular structure
1. Muscle
2. Fascicle
3. Muscle Fiber (cell)
4. Myofibril
5. Sarcomere
6. Myofilament
26
Myofibril
Organelle of the muscle fiber made up of sarcomeres which contract; an organelle
27
Types of filaments in a sarcomere
1. Myosin (thick filaments)
2. Actin (thin filaments)
3. Titin (elastic filaments)
28
Sarcolemma
Plasma membrane of a muscle fiber
29
Sarcoplasm
Cytoplasm of a muscle cell
30
Difference between fibers, myofibrils, and filaments
Fibers= cells, myofibrils= organelle, filaments= extended macromolecular structure
31
Z disc
Boundary of each sarcomere
32
A band
Width of myosin
33
I band
Area with NO myosin, overlaps 2 neighboring sarcomeres
34
H zone
Middle of the band that doesn't have actin
35
M line
Very center of the myosin
36
Titin
Helps muscle cell to spring back to shape after stretching. Stiffens as it uncoils to prevent the sarcomeres from being pulled apart
37
Two sets of intracellular tubules
Sarcoplasmic reticulum and T tubules
38
Sarcoplasmic reticulum
Modified smooth endoplasmic reticulum that stores calcium ions and releases them on demand when the muscle fiber is stimulated to contract
39
Muscle contraction
1. Nerve impulse travels down neuron
2. Axon terminal releases a neurotransmitter
3. NT diffuses through synaptic cleft (little gap) and binds to sarcolemma
4. Sarcoplasmic reticulum releases calcium ions which causes the myosin heads to to bind to the actin, ATP is then used to bend the myosin heads inwards
- these two things cause actin to get pulled towards the center of the sarcomere
- A band has not changed
- I band shrinks to the size of Z disc
- Hzone disappears
40
Sliding filament mechanism/ theory
Myosin and actin do not get shorter, they are just sliding over each other. Shortening the sarcomere
41
Muscle extension
Muscles do not forcibly lengthen. Gravity can pull a muscle back to its original length
- contracting a muscle on the opposite side of a joint can pull a muscle back to its original length
42
Motor unit
A neuron and all the muscle fibers that it innervates
- a muscle produces more or less force by using more or fewer motor units
- an individual motor unit can be very large (lots of muscle fibers per neuron) or very small (vice versa) nuance movements of facial muscles
43
Large motor units
Produce big movement and lots of force
44
Small motor units
Produce small, subtle movement/ little force
45
Muscular dystrophy
A group of inherited muscle destroying diseases that generally appear during childhood. The muscle cells enlarge initially then atrophy and disintegrate. Most common form is Duchenne muscular distrophy common in males
46
Duchenne muscular distrophy
A type of MD caused by a recessive gene in mostly male children which produces a defective cytoplasmic protein (dystrophin). Starts at 2-7 in healthy children, disease progresses from extremities upward to face, chest and heart muscles.Victims rarely live beyond 20s dying of respiratory failure
47
Fibromytosis
Fibromyalgia, a group of of conditions involving chronic inflammation of a muscle it's connective tissue coverings and tendons and capsules of nearby joints. Symptoms: tenderness, fatigue and frequent awakening from sleep
48
Hernia
Protrusion of an organ through its body cavity wall. Can be congenital or caused by heavy lifting, obesity and muscle weakening
49
Myalgia
Muscle pain
50
Myofascial pain syndrome
Pain caused by tightened band of muscle fibers, which twitch when the skin over them is touched. Overused or strained postural muscles
51
Myopathy
Any disease of the muscle
52
Myotonic dystrophy
Less common form of MD. Not sex specific. Gradual reduction in muscle mass and control if muscles.abnormal heart rhythm and diabetes. Worse in subsequent generations because gene repeats more
53
RICE
Rest, ice, compression and elevation. Standard treatment for a pulled muscle or extensively at reached tendons and ligaments
54
Strain
Commonly called a pulled muscle.excessive stretching of the muscle causes it to tear. Due to over use and abuse. Injured muscle becomes inflamed adjacent joints are immobilized
55
Spasm
A sudden involuntary twitch in smooth or skeletal muscle ranging from merely irritating to very painful. Facial an eyelid spasms are called tics and could possibly indicate a psychological factor. A cramp is a prolonged spasm
56
Tetanus
A state of sustained contraction of a muscle that is a normal aspect of skeletal muscle functioning. A disease cause by a bacteria resulting in painful spasms of certain skeletal muscles, which then turns into fixed rigidity of the jaw (lockjaw) and spasms of the trunk and limb muscles. Fatal due to respiratory failure
57
What happens when a muscle shortens
The insertion (attachment to the movable bone) moves towards its origin (fixed immovable point of attachment)
58
4 functional groups of muscles
1. Prime movers
2. Antagonists
3. Synergists
4. Fixators
59
Prime mover
Or agonist(leader) has responsibility for producing a specific movement ex. Pectoralis major a prime mover of arm flexion
60
Antagonist
(Against the leader) serves to stretch or remain relaxed. Helps to regulate action of prime mover by providing resistance and helps to not overshoot the mark and helps to slow down or stop a movement
Ex. Latissimus dorsi
61
Prime movers and antagonists are located
On opposite sides of the joint across which they act on
62
Synergist
Help prime movers
63
Synergists help prime movers in what 2 ways?
1. Adding a little extra force to the same movement
| 2. Reducing undesirable or unnecessary movements that might occur as the prime mover contracts
64
Fixators
When a Synergist immobilized a bone or a muscle's origin so that the prime mover has a stable base on which to act, they are called fixators
65
A muscle may
Serve as a antagonist or Synergist or prime mover in different movements
66
Types of fascicle arrangement (muscle pattern)
1. Parallel
2. Convergent
3. Pennate
3. Circular
67
Parallel fascicle arrangement:
Strap like or fusiform. Ex. Sartorius (strap like) biceps brachii (fusiform)
68
Fusiform
Wider in the middle and tapered at the ends
69
Convergent fascicle arrangement:
Fascicles come together at insertion ex. Pectoralis major
70
Pennate fascicle arrangement
"Feather-like"
71
3 forms of pennate muscles
1. Unipennate; extensor digitorum long us
2. Bipennate; rectus femorus
3. Multipennate; deltoid
72
Circular fascicle arrangement
When fascicles are arranged in concentric rings. Surround external body openings. Sphincters (squeezers) ex. Orbicularis muscles
73
Skeletal muscles are named by what 7 ways
1. Location
2. Shape
3. Relative size; Maximus, minimums, longus, brevis
4. Direction/arrangement of fascicles; rectus(straight), transverse, oblique(angle)
5. Location and attachments (origin and insertion)
6. The number or orgins (-ceps, biceps, triceps, ect.)
7. Action
74
Charley horse
A muscle contusion. Tearing of the muscle followed by hematoma and pain
75
Electromyography
A recording and interpretation of graphic records of the electrical activity of contracting muscles. Best way of determining functions of muscles and muscle groups
76
Hernia
Abnormal protrusion of abdominal contents. Goes through weak spot in muscle
77
Quadriceps and hamstring strain
Also called pulls. Tearing these muscles at the tendons. Common athletes who do not warm up properly and fully extend their hip or knee quickly or forcefully
78
Ruptured calcaneal tendon
Common injury to Achilles' tendon. Happens mostly in older people or young sprinters. Exaggerate dorseflexion and plantar flexion almost impossible. Calf bulges. Repaired surgically.
79
Shin splints
Pain in the anterior compartment of the leg, caused by irritation of the tibialis anterior muscle. Follows extreme or unusual exercise without adequate prior conditioning
80
Tennis elbow
Tenderness due to trauma or overuse of the tendon of origin of the fore arm extensor muscles at the lateral Epicondyle of the humerus
81
Torticollis
(Tort= twisted) a twisting of the neck in which there is chronic rotation and tiltin of the head to one side. Due to injury of the sternocleidomastoid on one side; also called wryneck
82
Overall Function of the nervous system
The master controlling and communicating system of the body
83
3 functions of the nervous system
1. Sensory input
2. Integration
3. Motor output
84
Sensory input
Receptor monitor change inside and outside the body.
85
Integration
Processing and interpreting sensory input, making decisions; dictates the response
86
Motor output
Response (control muscle, glands, etc)
87
Divisions if the nervous system
1. Central Nervous system
| 2. Peripheral nervous system
88
Central nervous system
- consists of brain and spinal chord
| - performs integration
89
Peripheral nervous system
- consists of nerves, ganglia, receptors etc
| - involved in sensory and motor
90
Afferent
(Sensory)
| Involves somatic sensory and visceral sensory
91
Efferent
(motor) somatic motor and visceral motor
92
Autonomic nervous system
Consists of visceral motor nerve fibers that regulate the activity of smooth muscles, cardiac muscles and glands; involuntary nervous system
93
Somatic nervous system
Composed of somatic motor nerve fibers that conduct impulses from CNS to skeletal muscles; voluntary nervous system
94
Somatic sensory fibers
Fibers convey impulses from the skin, skeletal muscles and joints (soma= body)
95
Visceral sensory fibers
Transmit impulses from guts within ventral body cavity
96
Neurons
Nervous system cells that transmit electrical signals
97
Neuroglia
Support and protect neurons
98
Special characteristics of neurons
- conduct electrical impulses down the length of a cell
- longevity: can live and function for entire life time
- do not divide: can not be replaced
- high metabolic rate: uses a lot of o2 and glucose
99
Parts of a neuron
1. Cell body; contains organelles
2. Chromataphilic bodies; rough ER
3. Dendrites; numerous and branched, receptor sites
4. Axon; only one, has terminal branches at its end, generates and conducts impulses, releases neurotransmitters
100
What do dendrites, the cell body and axons do?
Dendrites and cell body receive info and and axons send info
101
How are neurons classified?
1. Structure
| 2. Function
102
Functional classification of a neuron
1. Sensory neurons (afferent)
2. Interneurons
3. Motor neurons (efferent)
103
Sensory (afferent) neurons
Send messages toward CNS; located in PNS
104
Interneurons
Involved in integration; found in CNS
105
Motor (efferent) neurons
Send messages away from CNS; located in PNS
106
Structural classification of neurons (# of processes)
1. Multipolar
2. Bipolar
3. Unipolar
107
Multipolar neurons
Have many dendrites and one axon; can be motor or Interneurons
108
Bipolar neurons
One dendrite, one axon only found in special sense organs
109
Unipolar neurons
One axon typically sensory neurons
