Muscular system Flashcards
properties of muscle tissue
excitability
contractility
extensibility
elasticity
the ability to respond to certain stimuli by producibg electrical signals such as action potential
electrical excitability
ability to shorten and thicken, generating force to do work
contractility
ability to extend without damaging the tissue
extensibility
ability to return to original shape after cotraction or extension
elasticity
problems involving somatic motor neurons, neuromuscular junctions or muscle fibers
neuromuscular disease
signifies a disease or disorder of the skeletal muscle tissue itself
myopathy
autoimmune disorder characterized by great muscular weakness abd caused by antibodies directed against ACh receptors at the neuromusculat junctions
myasthenia gravis
inherited muscle destroying diseases characterized by degeneration of individual muscle fibers
muscular dystrophies
painful, non articular rheumatic disorder that usually appears between the ages of 25 and 50
fibromyalgia
sheet like attachment kn muscles connected to connective tissues or other muscles
aponeurosis
sheet or band of fibrous connective tissue that is deep to the skin and surrounds muscles and other organs of the body
fascia
from where do skeletal muscle fibers arise
myoblasts
a motor neuron and all of the muscle fibers attached to it
motor unit
the part of the motor neuron that leads to a muscle fiber
axon
the connection/ synapse between the terminal branches of an axon and the sarcolemma of a muscle fiber
neuromuscular junction
depressions in the sarcolemma
motor end plates
tiny space betweem the axon terminal and the sarcolemma
synaptic cleft
the neurotransmitter which activates muscle movement
Acetycholine
sliding of filament and shortening of sarcomeres
sliding filament mechanism
four events of the contraction cycle
ATP hydrolysis energizes myosin
myosin attaches to actin to form crossbridges
powerstroke when the actin moves towards the center
detachment of myosin causing ATP binding
decomposes acetylcholine in the synaptic cleft
acetycholinesterase
serves as a limited storage form of readily available energy
creatine phosphate
cellular respiration two steps
anaerobic phase in the cytoplasm
aerobic phase in the mitochondria
the amount of oxygen required to metabolize the accumulated lactic acid and resupply ATP
oxygen debt
muscle tissue two sources of oxygen
diffusion from blood
release by myoglobin inside muscle fibers
the inability of a muscle to maintain its strength of cintractiom or tension
muscle fatigue
elevated ixygen use after exercise
recovery oxygen uptake
brief contraction of all the muscle fibers in a motor unit in response to a single action potential
twitch contraction
a record of a muscle contraction
myogram
three periods of a myogram
latent, contraction, and relaxation
time when a muscle has temporarily lost excitability
refractory period
the minimal strength of a stimulus needed for it to contract
threshold stimulus
contraction is not proportional to the strength of the stimulus
all or none response
the brief interval after the stimulus is applied but before the muscle starts to contract
latent period
the muscle shortens rapidly
period of contraction
muscle returns to its former length
period of relaxation
shortened interval between stimuli where muscle fibers cannot completely relax causing incteased strength of contraction
wave summation
stimuli that is so frequent that relaxation is not possible
tetanic contraction
a sustained muscle contraction with partial relaxation between stimuli
incomplete/ unfused tetanus
a sustained contraction that lacks even partial relaxation between stimuli
complete/ fused tetanus
process of increasing the number of active units to prevent fatigue and help smooth muscle contraction
recruitment (multiple motor unit summation)
varying degrees of contraction by whole muscles
graded responses
the state of constant partial contraction which keeps a muscle ready to respond
muscle tone
involuntary painful sustained tetanic contractions of a muscle
cramp
abnormal increase of fibrous connective tissue in a muscle
fibrosis
inflammation of the connective tissue, especially muscle sheaths and fascias
fibrositis
inflammation of muscle tissue
myositis
pulled muscles resulting from stretchinge excessively
strains
caused by the bacterium Clostridium botulinum which prevents release of acetycholine from the tips of motor neurons
botulism
viral disease of motor neurons in the spinal cord
poliomyelitis
sudden involuntary contraction of a muscle or group of muscles
spasms
caused by the anaerobic bacterium Clostridium tetani which produces a neurotoxin that affects motor neurons in the spinal cord, first affecting the mandible “lockjaw”
tetanus
skeletal muscle fibers that are small, dark, and slow to contract, but fatigue resistant
slow oxidative
skeletal muscle fibers that are medium in size, dark and have medium contraction force and fatigue resistance
fast oxidative- glycolytic
skeletal muscle fibers that are large, white and have a rapid contraction rate but fatigue easily
fast glycolytic
