Muscle Physiology pt 2 Flashcards
The Theory for the movement of the muscle fiber____
States that during contraction the THIN filaments SLIDE past the THICK filaments so the actin and myosin filaments OVERLAP
By _____ in
Sliding FIlament Theory of Contraction
Hugh Huxley
1954
_____ Consists of many myosin_____ molecules whose head protrude at opposite ends of the filament.
____ Consists of two strands of Actin subunits twisted into a helix plus two types of regulatory proteins (____ and ____)
Thick Filament
Myosin
Thin Filament
Troponin
Tropomyosin
INITIAL:
_____ binds to ____
____ shifts ____
SEQUENCE OF EVENTS INVOLVED IN SLIDING OF ACTIN FILAMENTS DURING CONTRACTION:
- _____
> _____ in _____ attaches to ___
> This is the ____
Has: ____ and ____ - _____
>_____ is released, initiates ____
> _____ bend and pulls on ___ to slide it to ____
> ____ is released
INITIAL:
CA2+ binds to TNC
Troponin shifts Tropomyosin
- CROSS BRIDGE ATTACHMENT
> Myosin head in High-Energy Configuration attaches to Actin
> This is the Cross Bridge
Has: ADP + Pi - POWER STROKE
> inorganic Phosphate (Pi) is released, initiates Power (working) stroke
>Myosin head bend and pulls on Actin to slide it to M line
>ADP is released
SEQUENCE OF EVENTS INVOLVED IN SLIDING OF ACTIN FILAMENTS DURING CONTRACTION:
- CROSS BRIDGE ATTACHMENT
> Myosin head in High-Energy Configuration attaches to Actin
> This is the Cross Bridge
Has: ADP + Pi - POWER STROKE
> inorganic Phosphate (Pi) is released, initiates Power (working) stroke
>Myosin head bend and pulls on Actin to slide it to M line
>ADP is released - _____
> _____ attaches to ____ (____)
> _____ detaches - _____
>_____ is split into ____ and ____
>_____ is ___ into ____
- CROSS BRIDGE DETACHMENT
> ATP attaches to Myosin head (low-energy configuration)
> Cross Bridge - “Cocking of Myosin Head”
> ATP is split into ADP and Pi
>Myosin Head is cocked into High-energy Confirmation
REGULATION of Muscle Fiber Contraction
_______
STEP 1 and 2 Occurs at ____
- ____
- _____ (____) generated in _____
STEP 3 and 4 link ____ to _____
- ____ propagated along ____
- Intracellular ____ levels rise briefly
Excitation - Contraction Coupling
STEP 1 and 2 Occurs at Neuromuscular junction
- Nerve Stimulation
- Action Potential (Electrical Current) generated in Sarcolemma
STEP 3 and 4 link Electrical Signals to Contraction
- Action Potential propagated along Sarcolemma
- Intracellular Ca2+ levels rise briefly
REQUIREMENT for Skeletal Muscle contraction
____ neural stimulation at a neuromuscular junction
____ Generation and propagation of an action potential along the Sarcolemma
_____ brief rise of Ca2+ levels
Activation
Excitement - Contraction coupling
Final Trigger
Excitation-Contraction Coupling Summary
In response to an action potential, a ____ motor neuron with ____ releases ____
Net entry of ___ through the ____ which intiates a muscle action potential
Other Channels specifically
Extracellular____
Intracellular ____
Somatic Motor Neuron
Synaptic Vesicles
Acetylcholine
ACh receptor-channel
Extracellular: Dihydropyridine L=type Calcium channe;
Intracellular: Ryanodine Receptor-Channel
Sequence of events involved in Excitation-Contraction coupling
INITIAL: ____ attaches to the ACh receptors in ___
1) Action potential generated is moved down the ____
2) Action Potential triggers ____ release from ____ of ___
3) _____ bind to ___ which shifts the position of the ____
4) _____: cross bridges pull, detach, attach with the release of energy
5) Removal of ____ by ACTIVE transport into the ___ after action potential ends
6) _____ restored and blocks the ___, muscle fibers relax
INITIAL: Acetylcholine attaches to the ACh receptors in Sarcolemma
2) Action Potential triggers CA2_ release from Terminal cistern of Sarcoplasmic reticulum
3) Calcium ions bind to Troponin which shifts the position of the tropomyosin
4) Contraction: cross bridges pull, detach, attach with the release of energy
5) Removal of Ca2+ by ACTIVE transport into the Sarcoplasmic reticulum after action potential ends
6) Tropomyosin Blockage restored and blocks the Actin Active Site, Muscle Fibers Relax
_____ enzyme primarily found at postsynaptic neuromuscular junctions, especially in muscles and nerves. It immediately breaks down or hydrolyzes acetylcholine (ACh), a naturally occurring neurotransmitter
Acetylcholin esterase (AchE)
____ a small gap between the axon terminal of one neuron. where neurotransmitters are released to transmit signals from one neuron to the next
____ also known as the neuromuscular junction, is a specialized region where the motor neuron meets a muscle fiber.
synaptic cleft
Motor end plate
Development of End Plate Potential
1) ____ generation of the end plate potential on the Sarcolemma
Neurotransmitter: ____
2) Generation and propagation of the _____
Open ____ Closed ___
3) ______
Closed ____ open ____
1) Local depolarization
Neurotransmitter: Acetylcholine
2) Action Potential
Open Na+ ch Closed K+ ch
3) Repolarization
Closed Na+ ch Open K+ ch
______
Autoimmune disease in which a person produces antibodies to the _____ on Skeletal muscle fibers
The number of these receptors decreases and the synaptic transmission between motor neurons and muscle fibers become less effective
Myasthenia gravis
Acetylcholine receptor
_____
Toxins inhibit nerves by blocking Acetylcholine, so muscle can’t contract
Results from the consumption of the exotoxin ____
Also used in certain facial muscles to eliminate frown lines in ____ treatments
Botulism
Clostridium botulinum
Botox
Botulism Symptoms (7)
Double Vision
Blurred Vision
Droopy Eyelids
Slurred Speech
Difficulty Swallowing
Dry Mouth
Muscle Weakness (starts in shoulders)
