Exam 3 review Flashcards
What are the muscles 4 major functional properties?
Contractility, Excitability, Extensibility, Elasticity
What does it mean for a muscle to have “contractility”?
The ability of muscle cells to forcefully shorten
What does it mean for a muscle to have “excitability”?
The ability to respond to a stimulus, which may be delivered from a motor neuron or a hormone
What does it mean for a muscle to have “Extensibility”?
the ability of a muscle to be stretched
What does it mean for a muscle to have “elasticity”?
The ability to return to normal length after a stretch
Where is the EPIMYSIUM in the muscle cell?
dense irregular connective tissue which covers the entire muscle
Where and what is the PERIMYSIUM on a muscle cell?
connective tissue that groups muscle fibers into bundles or fascicles
Where and what is ENDOMYSIUM in muscle cell?
connective tissue that surrounds a muscle cell
* key element that separates single muscle fibers from one another.
How do muscles grow bigger?
Hypertrophy - increase in diameter more proteins in cell (myofibrils sarcomeres and nuclei from satellite cells)
*Connective tissue and sarcoplasmic hypertrophy
What is Titan?
Protein that gives muscles ability to stretch and recoil
Z disk to M line
What are the 3 proteins that make up actin?
Globular
Actin
Troponin
Where is Ca2+ stored in muscle fiber?
Sarcoplasmic reticulum
What are 3 important properties of myosin heads?
- Bind to actin
- Can bend and straighten during contraction
- Heads are ATPase which break down ATP
Neurotransmitters can bind to what and cause what?
Ligand gated ion channels and inhibit or excite an action potential
From muscle to myofilament, describe the components large to small
Muscle -> Fascicles ->Muscle fiber/cell -> myofibrils -> myofilaments
Myofibril is numerous sarcomeres
What are the 4 phases of contraction and relaxation?
- *Excitation** - Nerve action potentials lead to muscle action potentials (presynaptic terminal to post)
- *Excitation-contraction coupling** - Action potentials in sarcolemma (release of Ca2+ that binds to troponin) that lead to activation of myofilaments
- *Contraction -** Myosin attaches to action and power stroke (contraction)
- *Relaxation -** Muscle fiber relaxes and returns to original length
What is a synapse?
A point where a nerve fiber meets its target cell (could be another neuron or effector such as a gland or skeletal muscle)
What are the 2 major gated ion channels in skeletal muscles?
Ligand and voltage gated channels
When does depolarization start?
When threshold is met, then Na2+ gated channels open (more postive)
When does repolarization start?
Between 30-40mv, in this range voltage gated Ca2+ close and K+ open (more negative)
What does acetylcholinesterase do?
Its an enzyme attached to post synaptic membrane, removes ACH from synaptic cleft by breaking it down into acetic acid and choline
(Choline goes back into presynaptic terminal with Ca2+ to be recycled and acetic acid diffuses away)
What is spastic paralysis?
Aka - Tetanus / lockjaw
A state of continual contraction
when something binds with acetylcholinesterase and prevents it from degrading ACH
What is flaccid paralysis?
Botox
- State in which muscles cannot contract
- Blocks release of ACH
What parts of the sarcomere move and get smaller during a muscle contraction?
Z disks move inward, I bands and H zone get smaller
What are 3 ATP dependent events required for muscle relaxation?
- Na+/K+ pump actively moves ions to restore RMP
- Detach myosin heads from action
- Return Ca2+ to sarcoplasmic reticulum
What are the 3 phases of myogram?
Lag
Contraction
Relaxation
What is the lag or latent phase of a muscle twitch?
The time between the activation of a motor neuron until the muscle contraction occurs
1-2msec
What is the contraction phase of a muscle twitch?
Cross bridges form, sarcomeres shorten and muscle contracts
20msec
What is the Relaxation phase of a muscle twitch?
Myosin releases from action and the tension decreases. Ca2+ is transported back into sarcoplasmic reticulum
This phase is the longest
What are 2 major types of muscle contraction?
ISOTONIC
ISOMETRIC
What is an ISOMETRIC contraction?
SAME LENGTH, change in tension
Example, Holding a dumbbell static. Picking up something that is too heavy
What is an ISOTONIC contraction?
SAME TENSION, change in length
Maintain constant tension as the muscle changes length
Ex. bicep curl
What is treppe?
Staircase effect.
the gradual increase in muscular contraction following rapidly repeated stimulation
What is wave summation
stimulating a muscle cell before it has relaxed from a previous stimulus
What is the difference between incomplete and complete tetanus?
Incomplete tetanus has a relaxation phase during contractions and complete tetanus does not have a relaxation phase during contractions
What are concentric contractions?
Muscle shortening as it maintains tension, to move a load
Lifting a backpack
What are eccentric contractions?
Muscle lengthens as it maintains tension, lowering a load
How many power strokes can happen per sec?
5
each stroke utilized 1 ATP
What are the 2 ways to increase the force of a muscle contraction?
Summation - stimulating before it relaxes
Recruitment - different motor units are activated
What are slow twitch muscle fibers?
- Contract slowly / can work for a long time
- Aerobic respiration (Oxygen)
- Lots of blood vessels and mitochondria
- Rich in myoglobin which gives reddish color
What are fast twitch muscle fibers?
- Contract quickly
- Tire very quickly / doesn’t last long
- Anaerobic respiration
-Fewer mitochondria, blood vessels and myoglobin which gives them a whitish color
What are the 3 sources that produce ATP?
-Creatine phosphate - which donates a phosphate to ADP = ATP
-Lactic acid fermentation under anaerobic conditions - Glycolysis → 2 ATP, 2 pyruvate, 2 NADH → 2 pyruvate produce 2 lactic acid (2 ATP)
-Aerobic respiration - Requires oxygen. Glycolysis→ Pyruvate→Citric acid cycle→ electron transport chain → (36 ATP)
What are the 3 sources that produce ATP?
-Creatine phosphate - (no oxygen - 10 sec) which donates a phosphate to ADP = ATP
-Lactic acid fermentation under anaerobic conditions - (no oxygen - 3 min) Glycolysis → 2 ATP, 2 pyruvate, 2 NADH → 2 pyruvate produce 2 lactic acid (2 ATP)
-Aerobic respiration - (Requires oxygen - hours) Glycolysis→ Pyruvate→Citric acid cycle→ electron transport chain → (36 ATP)
What are the 3 types of muscle fatigue?
Psychological - perceives that cant do it
Muscular - ATP depletion
Synaptic - lack of ACH
What is creatine kinase?
Transfers a phosphate from creatine to ADP = ATP
What are the characteristics of smooth muscle?
- Spindle shaped
- Single nuclei centrally located
- Gap junctions join some together
- More action than myosin
- T tubules are called Caveolae
- Z disks are dense bodies
What is the process of smooth muscle contraction?
- Hormones’ binds with receptor → activates G protein which opens calcium channel
- Ca2+ then binds to calmodulin
- This activates myosin kinase which adds a phosphate to myosin which can bind to actin
How does smooth muscle relax?
Myosin phosphatase will come in and remove the P from myosin head and it will relax
What is an agonist muscle?
Muscle that contracts or shortens
aka Prime mover
What is an antagonist muscle?
- opposite the agonist
- Relaxes and lengthens as agonist shortens and contracts
Can control speed of movement
What is a synergist?
Other muscles that work together with prime mover to cause a movement
Prime mover - plays major role in accomplishing movement
Fixators - Stabilize a joint / prevent movement of origin
What pattern of fascicle is the picture?
Convergent aka triangular
The origin (attachment to fixed bone) is wider than the point of insertion
Ex. pectoralis major
What pattern of fascicle is in this picture? definition and example
Circular
Sphincter to help regulate an opening
ex. eye
What pattern of fascicle is in this picture? definition and example
Fusiform
A muscle that has a shape of spindle, which is being wider in the middle and narrowing towards both ends
Ex. biceps brachii
What pattern of fascicle is in this picture? definition and example
Parallel
Fascicles that run parallel to one another
Ex. Sternocleidomastoid
What pattern of fascicle is in this picture? definition
Unipennate
the muscle fibers or fascicles are all in one side of the tendon
What pattern of fascicle is in this picture? definition and example
Bipennate
in which the fibers converge from both sides to a central tendon
What pattern of fascicle is in this picture? definition
Multipennate
fascicles that insert on multiple tendons tapering towards a common tendon, like multiple feathers converging on a central point.
What are the characteristics used to name muscles?
Location, size, shape, orientation of fascicles, origin and insertion, number of heads, function
What is a
lever
Fulcrum
Weight/resistance
- *Lever** is rigid shaft or bone
- *Fulcrum** is pivot point or joint
- *Weight** is force of gravity of body or object being moved
What is a class I lever?
Seesaw
Fulcrum between force and weight
What is a class II lever?
Weight is between fulcrum and pull
Wheelburrow
What is a class III lever?
Pull located between fulcrum and weight
Person using a shovel
*most numerous and most powerful
Where on the axon is dense with voltage gated ion channels?
Axon hill lock
Nodes of Ranvier
What is the somatic sensory division?
Carries signals from receptors in skin, muscles, bones and joints
What is the visceral sensory division?
Carries signals from the viscera of thoracic and abdominal cavities
What is the sensory afferent division?
Carries signals from various receptors to CNS
What is the motor efferent division?
Carries signals from CNS to effectors
What is the somatic motor division
CNS to skeletal muscle
What is the visceral / automonic division?
CNS to cardiac muscle, smooth muscle or glands
What is spatial summation?
occurs as stimuli are applied simultaneously but in different areas.
What is temporal summation?
Successive stimuli on one nerve
What is IPSP?
Inhibitory Post Synaptic Potential
Makes more negative // away from action potential
*GABA / glycine / Cl- or K+ (hyperpolarization)
What is EPSP?
Excitatory Post synaptic Potential
*Brings potential less negative and more likely to fire an action potential
Glutamine / Acetacholine / Na+ channel opens
What is Autorhythmicity
Generating its own rhythm //on its own without outside stimulus
What are the 3 types of skeletal muscle fibers?
- *TYPE 1 - Slow oxidative (SO)** - Contract slowly and use aerobic respiration
- *TYPE 2A - Fast oxidative (FO)** - Contract fast and use aerobic respiration/ more prone to fatigue
- *TYPE 2 B- Fast glycolic (FG)** - Fast contractions and use anaerobic glycolysis (fatigue more quickly)
