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23 terms

Muscular System

STUDY
PLAY
properties
contraction
extendability
elasticity
exicitability
excitability
responding to stimuli by nerves through neurotransmitters
structure
bone
tendon
fascia
muscle
fascicle
fibers
myofibrils
fast-twitch muscle
shorter endurance (white meat)
more capillaries per mass of fibers (more myoglobin)
slow-twitch muscle
longer endurance (dark meat)
less capillaries per mass of fibers
actin
thin protein that contains tropomyosin and troponin
myosin
thick protein: many fibers with heads
myosin heads contain...
ATP that break down ADP+P
cross-bridges are formed when...
myosin heads attach to the actin
each muscle is served by
1 nerve
1 artery
1 or more veins
muscle contraction
1) brain signals motorneuron
2) neuron and muscle meet
3) neurotransmitters are released
4) calcium ions diffuse into cytoplasm
5) calcium bonds to troponin (changes shape)
6) myosin attaches to actin and bends
7) more ATP comes in and releases
in step 3, what is the chemical that is released?
Acetylcholine (ACH)
in step 6, what is the process of bending?
-ADP+P are attached to the heads
-ADP+P are released when it moves and then it bends
muscular diseases
botulism (botox)
poliomyelitis
tetanus
ALS
rigor mortis
-no oxygen>no ATP>no immediate contraction
-sets in 2 or so hours after death (can last 72)
-membrane permeability increases and causes calcium ions to flood in, and cross bridge attachment occurs
types of muscle contractions
isometric & isotonic
isometric muscle contraction
length does not change, but the amount of tension is increased
isotonic muscle contraction
length changes and tension is constant (concentric vs. eccentric)
concentric
shorten
eccentric
lengthen
muscle tone
continuous state of partial contraction
muscle relaxation
an enzyme decomposes any acetylcholine
-ATP sends Ca ions back into sarcoplasmic reticulum; ATP breaks the fiber link
glycogen
made in the liver, a carb, reservoir for glucose