Muscle Flashcards
How many muscles are in the body?
600
What percent of your body weight do muscles take up?
40% (50% if you count smooth muscle)
What does the word “mus” mean?
Little mouse
How much could you lift if you used all of your potential power at once?
25 tons
What is the only thing muscles can do?
Contract
What are the functions of muscles? (4)
- Create movement
- Maintain posture
- Stabilize joints
- Generate heat
Where is fascia located?
Between muscles and skin
What are the external structures of muscles? (3)
- Origin
- Belly
- Insertion
What is the order when labeling a muscle? (5)
Muscles, fascicles, fibers, myofibrils, myofilaments
How many myofilaments are there in muscles?
Over 65 million
What is the dark area on a myofilament? (A-band)
Myosin
What is the light area on a myofilament? (I-band)
Actin
What surrounds a fiber?
Endomysium
What surrounds a fascicle?
Perimysium
What is another name for a cell?
Sarcolemma
What is between myofibrils?
Sarcoplasm
What does Sarco- mean?
Flesh
What is a sarcomere?
One z-line to the next
What do tendons do for us?
Provide durability, conserve space
What are the three types of muscles?
Skeletal
Cardiac
Smoothe
What kind of muscle is this?
- Cigar-shaped cells
- many nuclei per cell
- voluntary
- fast-moving but tires easily
- 40% of bodyweight
- attached to skeletal bones
Skeletal muscle
What kind of muscle is this?
- Spiral-shaped cells
- one nucleus per cell
- involuntary
- slow-acting but tireless
- have intercalated disks
- found only in the heart
Cardiac muscle
What kind of muscle is this?
- spindle-shaped cells
- one nucleus per cell
- involuntary
- slow acting but tireless
- arranged in sheets or layers
- found in internal organs that are usually hollow
Smooth muscle
What is an example of a muscle named by the # of heads?
biceps, triceps
What is an example of a muscle named by its location?
pectoralis, gluteus
What is an example of a muscle named by its shape?
deltoid, trapezius
What is an example of a muscle named by its size?
maximus, medius
What is an example of a muscle named by its depth?
internal, external
What is an example of a muscle named by its origin and insertion?
sternocleidomastoid
What is an example of a muscle named by its direction?
rectus, oblique
What is an example of a muscle named by its function?
flexors, extensors
The ability to receive and respond to stimuli
Excitability
The ability to shorten when adequately stimulated
Contractility
The ability of a muscle to be stretched
Extensibility
The ability to recoil and resume resting length
Elasticity
One neuron and all of the skeletal muscles it stimulates
Motor unit
Where the neuron’s axon terminal inserts into the muscle
Neuromuscular junction
contractions take a few thousandths of a ___________
second
The muscle is unable to contract, though still being stimulated
Muscle Fatigue
Myofilaments are successful in their sliding movements and the muscle shortens
Isotonic contractions
Muscles do not shorten much, myofilaments “spinning their wheels”
Isometric contractions
Continuous partial contractions, muscle remains firm, healthy, and ready for actions
Muscle tone
What type of exercise is this?
- stronger, more flexible muscles with greater resistance to fatigue
- blood supply to muscle increases
- muscles form more mitochondria to hold oxygen
- overall body metabolism is more efficient
Aerobic Exercise
What type of exercise is this?
- increases muscle size
- more contractile fivers and connective tissues which reinforce development
Anaerobic Exercise
What is the quickening?
The first movements of the fetus that the mother feels 16 weeks
After birth, the first movements are __________ reflex types
Gross
Development goes from superior to:
Inferior
Development goes from gross movements to:
Fine movements
Development goes from proximal to:
Distal
As you get older, what happens to the amount of connective tissue?
It increases
As you get older, what happens to the amount of MUSCLE tissue?
It decreases
Muscles can only pull, therefore they work in __________
Pairs
Muscle with major responsibility in a group (agonist)
Primary mover
Muscles that oppose/reverse a movement
antagonist
Help prime movers by producing the same movement or by reducing undesirable movements.
Synergists
Specialized synergists. they hole a. bone still or stabilize the origin or a prime mover so all the tension can be used to move the insertion bone.
Fixators
Decrease the angle of joint. Hinge/bend
Flexion
Increase the angle of joint. Straightening knee, elbow, etc.
Extension
Away from the midline. Spread fingers and toes.
Abduction
Limb toward the midline. Closing fingers and toes.
Adduction
Moving a bone around its longitudinal axis
Rotation
Radius across ulna
Pronation
Radius parallel to ulna
Supination
Sole of foot faces medially
Inversion
Sole of foot faces laterally
Eversion
Foot up to shin (flex foot)
Dorsiflexion
Foot points down (point foot)
Plantar flexion
GENETIC DISORDER: Withering away (polio, muscular dystrophy, etc.)
Atrophy
GENETIC DISORDER: Partial paralysis of the facial muscles and loss of some taste on affected side. May happen overnight with no warning. Thought to be the result of a facial inflammation bothering the nerves. May correct itself with out any medication.
Bell’s Palsy
GENETIC DISORDER: Spasm in a muscle. Night leg cramps (calcium)
Cramps
GENETIC DISORDER: Steroid is a derivative of testosterone
Muscle Building
GENETIC DISORDER: Genetic disease, tiny tears won’t heal
Muscular Dystrophy
GENETIC DISORDER: Why we keep breathing hard after we stop exercising
Oxygen Debt
GENETIC DISORDER: Overstretched muscle so fivers tear. Muscle contracts and becomes swollen due to internal bleeding
Strained Muscle
GENETIC DISORDER: Overstretched muscle so fivers tear. Muscle contracts and becomes swollen due to internal bleeding, but worse than strained muscle, takes longer to heal
Torn Muscle
GENETIC DISORDER: Actin and myosin don’t let go when slide together at bonding site so the muscle stays contracted. Lasts about 24 hours, then decay softens
Rigor Mortis
GENETIC DISORDER: Either a stress fracture on distal part of tibia or tendonitis due to overuse.
Shin Splints
GENETIC DISORDER: Lactic acid builds up so causes pain. Slowly gets to liver and is broken down into sugar
Stiffness
GENETIC DISORDER: Inflamed, swollen muscle due to overuse.
Tendonitis
GENETIC DISORDER: Sustained contractions of the muscle in the head and neck
Tension Headache
GENETIC DISORDER: Continuous stimulation of a muscle *bacteria in soil or a rusty nail
Tetanus