Class 1 Flashcards
Primary functions of the muscular system
- equilibrium
- force
- work
- transport
- heat production
Equilibrium in regards to muscles
posture, standing
Force in regards to muscle
changes in velocity of muscle shortening
Work in regards to muscle
displacement in direction of the force
Transportation in regards to muscle
Digestive system and circulation
Heat production in regards to muscle
Shivering reflex, maintaining body temperature
Which muscle type has the longest muscle twitch duration?
Smooth muscle
Which muscle type has the shortest muscle twitch duration?
Skeletal muscle
Skeletal muscle is attached to (-) by (-)
Bone by tendon
Skeletal muscle primary functions:
Locomotion and posture/balance
Voluntary controlled muscle:
Skeletal muscle
Can skeletal muscle be involuntary/unconcious?
Yes, reflexes
Cardiac muscle attached to (-)
Blood vessels
Cardiac muscle primary function:
Blood circulation, adequate blood volume and pressure
Involuntary controlled muscle types:
Cardiac and Smooth
How is the cardiac muscle moderated?
ANS and hormones
Smooth muscle attached to (-) and (-)
Wall of organs and blood vessels
Primary functions of smooth muscle:
Blood pressure, digestion, bladder control, air flow
How is the smooth muscle contraction moderated?
ANS and hormones
Which muscle types are uninucleate?
Smooth and cardiac muscle cells
Which type of muscle is multinucleate?
Skeletal muscle
During embryonic development how are muscle cells developed?
Many myoblasts fuse to form one skeletal muscle fiber
Why are skeletal muscle cells multinucleate?
Many myoblasts fuse together to make one skeletal muscle cell and each myoblast has its own nucleus
Action for both the smooth muscle and cardiac muscle are involuntary under the regulation of:
Autonomic nervous system and endocrine system
Skeletal muscle is voluntary and controlled by:
Somatic nervous system
Which muscle types have pacemaker activity?
Smooth and cardiac
What is a pace-making activity?
Ability to generate action potential that can initiate muscle contraction
Skeletal muscle contracts in response to what?
To a signal from a somatic motor neuron
What is the one skeletal muscle that the autonomic nervous system can influence?
The diaphragm
Pacemaking activities are modulated by what? Can they be initiates from this?
Autonomic nervous system, NO
Muscular tissue - 5 special properties
- Excitability
- Contractibility
- Extensibility
- Elasticity
- Adaptability
What is excitability in regards to muscle?
Ability to respond to stimuli by producing action potentials
Smooth and cardiac muscle action potential when excited initiated by
Initiated by pacemaker cells
Skeletal muscle action potential when excited initiated by
Chemical stimulus
Where does a chemical stimulus occur in skeletal muscle?
Neuromuscular junction where ACh is releases by motor neuron as neurotransmitter
What is ACh
A neurotransmitter, acetylcholine
Where is the neuromuscular junction?
Junction between somatic motor neuron and muscle
What is contractibility in regards to muscle?
Ability of muscular tissues to contract forcefully when stimulated by action potentials
What produces tension?
Contraction without muscle shortening
Greater the change in velocity of muscle fiber, greater the (-)
Force of contraction
What is the formula for force
F=ma
Force in regards to muscle produces what?
Movement
What is extensibility in regards to muscle?
Ability of muscular tissues to stretch without being damaged, within limits
What is elasticity in regards to muscle?
Ability of muscular tissues to return to its original length and shape after contraction or extension
What is the function of titin?
Provides elasticity and stabilizes myosin
Titin and nebulin are what?
Accessory proteins
What is the function of nebulin?
Helps to align actin
Where is titin found?
Spans the distance of from one Z disk to neighboring M line
Where is nebulin found?
Lies along thin filament, attaches to a Z disk but does not extend to the M line
What is adaptability in regards to muscle?
Muscular tissues have the ability to undergo hypertrophy or atrophy
What produces hypertrophy?
Exercise
2 types of skeletal muscle types:
- Slow-twitch oxidative fibers (type I)
- Fast-twitch oxidative/glycolytic fibers (type II)
2 types of type II skeletal muscle
- Type IIa (fast-twitch oxidative fibers)
- Type IIb/IIx (fast-twitch glycolytic fibers)
Each whole muscle can compose of multiple fiber types but one dominates the others (T/F)
True
Muscle fibers belonging to one motor unit are of the same muscle type (T/F)
True
Slow-twitch oxidative fibers are what type?
Type I
Slow-twitch oxidative fibers ATP break rate/velocity of muscle shortening
Relatively slowest
Type I muscle fibers use (aerobic/anaerobic) and are (high/low) energy efficiency
Aerobic and high
Slow-twitch oxidative fibers need:
Good oxygen supply
Slow-twitch oxidative fibers (-) of myoglobin, mitochondial and oxidative enzyme content, and (-) capillary density
abundance, high
Slow-twitch oxidative fibers adequate supply of ATP enable what?
High endurance and fatigue resistance
Fast-twitch oxidative fibers ATP break/velocity of muscle shortening
Medium/middle, quicker than type I
Type IIa use (aerobic/anaerobic)
Aerobic
Type IIa need:
Good oxygen supply
Fast-twitch oxidative fibers (-) of myoglobin, (-) mitochondial and (-) glycogen content, (-) blood capillary content
High, higher, more abundant, high
Type IIa are fatigue resistant but a (-) in endurance than type I
Decrease
Reservoir of storage for type IIa
Creatine phosphate, excess ATP during rest is used to synthesize creatine phosphate
Fast-twitch glycolytic fibers ATP break/velocity of muscle shortening
Fastest
Fast-twitch glycolytic fibers (aerobic or anaerobic)
Anaerobic
Fast-twitch glycolytic fibers (-) in myoglobin, (-) in mitochondria, and (-) glycogen content, (-) blood capillary supply
low, low, higher, poor
Type IIb are (-) fatigable and (-) in endurance
Easily, low
To and a contraction, what must be removed from the (-) back to the (-)
Ca, cytosol, SR
Sarco-endoplasmic reticulum calcium ATPase
Ending contraction, calcium removed from cytosol back to SR through this
Excitation-contraction coupling step 1
ACh released from somatic motor neuron
Excitation-contraction coupling step 2
ACh initiates an action potential in muscle fiber
Excitation-contraction coupling step 3
Action potential travels along sarcolemma into T-tubules and triggers Ca release from SR
Excitation-contraction coupling step 4
Ca binds with TnC and initiates muscle contraction
