Muscular System C5 L4 Flashcards
Which systems does Muscular System link and what is it response for ?
Links nervous and skeletal system and is responsible for movement.
What are 3 types of muscle in body
Skeletal
Cardiac
smooth
A) Cardiac muscle =
B) Smooth muscle =
C) Skeletal
A) heart
B) makes up tissues is internal organs
C)
most important in fitness industry
Skeletal muscle
Muscle tissue that connects to bones and generates the force that creates movement and assists homeostatis of the by producing heat
Anatomy of muscle is made up of
1) Fascia - connective tissue that surrounds muscles and bones
2) Epimysium (deep fascia)
3) Fascicles - largest bundles of fibers within a muscle and surrounded by
4) Perimysium -connective tissue surrounding a muscle facile
5) Endomysium connective tissue that wraps around individual muscle fibers w/in a fascicles
Tendons
Connect muscle to bones
(Overstretching = strain)
Ligaments
Connects bone to bone
Overstretched or torn = strain
Glycogen
Glucose (sugar) deposited and stored in liver and muscle cells in the form of CARBOHYDRATE
Myoglobin
Protein based molecule that carries 02 to the muscles
Myofibrils
Where muscle connection occurs. Actin and Myosin (myofilamnents) are located in myofobril
Myofilaments
The filoments of myofibril including actin and myosin.
Actin
Thin, stringlike mycofilaments that act with myosin to produce muscular contraction
Myosin
Thick myofilemrn that along with actin help produce muscular contraction.
Sacromere
The structural unit of the myofibril composed of actin and myosin between the zline
Z Line
The meeting point of each sacromere
Muscle anatomy flow chart
muscle (bundle of fascicles surrounded by epimysium or deep fascia) -> fascicle (bundles of muscle fibers surrounded by perimysium connective tissue) ->muscle fiber (bundles of Mobil’s surrounded by endomysium conn tissue)-> myofibril (collection of sacromeres - > sacromere (section of myofibril btwn z lines where muscle contractions occur) Myofilament - actin & myosin protein structures)
Neural activation
Communication link between muscular and nervous systems.
It’s the nervous systems signal to tell the muscle to contract.
Neuromuscular junction
Specialized site where nervous system communicates directly with muscle fibers
Synapse
A junction or small gap between motor neuron and muscle cells
Motor unit
A motor neuron and all the muscle fibers that it innervates (connects to)
Action potential
Nerve impulse related from CNS->PNS and into the muscle across the neuromuscular junction
Neurotransmitters
Chemical messages that cross the synapse between neuron & muscle and assist with nerve transmission
Basically translates the NS electrical message that the muscle can understand
Acetocholine (ACh)
Neurotransmitter that helps the action potential across synapse to initiate contraction
Power stroke
Myosin heads bind to actin and pull toward the sacromere center which glides the filaments towards each other to contract the muscle
Adenosine triphosphate (ATP)
High energy molecuie serves as main energy in body
Resting length
Power stroke ends and myosin detaches and moves back to original position
Type of 1 Muscle fiber
•slow twitch*
Red fibers.
(remember muscles are functionally divided into motor units with single motor unit consisting on one motor neuron
Small motor units more fatigue resistant and connect to (innervate) to small muscle fibers
Necessary for postural control & stabilization
Type ll Muscle fibers
Fast twitch
White fibers (low capillaries, mitochondria, myoglobin - low oxidative state)
Larger motor units - faster to fatigue and innervate (contact) to larger muscle fibers. Important for physical activity that require large force like running
All or Nothing principle
Motor units can NOT vary the amount of force they generate; they either contract maximally or not at all
Capillaries (abundant in slow twitch)
Smallest blood vessel and site of exchange between blood and tissues.
Myoglobin
Similar to hemoglobin’s
Type ll muscle fibers have 2 types
Type lla (higher oxidative state) and Type llx
Called intermediate fast twitch fibers.
After age 50
Muscle mass lost by average of
1-2%/yr
Strength lost between 1.5-5%/yr
concentric contraction
is a type of muscle contraction in which the muscles shorten while generating force, overcoming resistance
