Test 2 Study Guide Part 5 Flashcards
Tendon:
Ligament:
Muscle to bone
Bone to bone
Origin:
Insertion:
Is the attachment point to the stationary bone
Is the attachment point to the bone which moves
Flexion:
Extension:
Flexion:
You flex a joint, not a muscle
Extension:
Prime mover:
- Other name:
- Meaning:
- Muscle which opposes prime mover:
- Other name: Agonist - Meaning: The muscle which does most the work in a motion. - Muscle which opposes prime mover: Antagonist
Muscle Fiber is also:
A muscle cell
Fascicle:
A collection of muscle fibers
Endomysium:
Connective tissue between muscle fibers.
Perimysium:
connective tissue between fassicles
Epimysium:
Surrounds an entire muscle
What is the plasma membrane of a muscle cell called?
Sarcolemma
What is the endoplasmic reticulum of a muscle cell called?
Sarcoplasmic reticulum
Syncytial:
Multinucleated
Why are skeletal muscle cells syncytial?
They are formed by multiple muscle cell precursors merging together into a single cell.
What produces the striation of muscles? (skeletal)
banding, the actin myosin structure causes bands.
Where is the cell body of a motor neuron located?
Ventral horn of the gray matter of the spinal cord
Motor unit:
- Define:
- Contraction:
- Define:
A somatic neuron and all muscle fibers it innervates - Contraction:
All muscle fibers of the motor unit will contract if the somatic neuron is fired
Graded contractions:
- Define:
- Achieved by:
- Define:
Contraction where muscle strength is varied - Achieved by:
asynchronous stimulation of different motor units (allows the muscle contraction to be sustained
How is fine motor control achieved?
Motor units have less muscle fibers (23 in the eye vs 2000 muscle fibers in some leg muscling)
Recruitment:
Process by which more and more motor units are recruited (smallest to heaviest) slowly resulting in gradual ability to lift something heavy
Which two forces work to increase the force of a muscle contraction?
- Motor units involved are stimulated asynchronously at a greater frequency
- Recruitment of larger motor units with more muscle fibers per motor neuron
Myofibril:
Packages of myofilaments (actin and myosin) found within muscle cells
Myofilament:
Actin or myosin
Sarcomere define:
Distance form Z line (z disk) to Z line (z disk)
Z line (Z disk): M line:
Z line (Z disk): protein structure which actin attach to on both sides M line: protein structure which myosin attaches to on both sides
What sweet way did you pioneer to remember muscle striation bands?
IZIAHMHAIZI
Name the bands in order of your sweet structure
Z band/disc: actin attachment point I band: (area where myosin is not found) A band: area where myosin is at H zone: area which does not have actin M line: middle proteins in myosin filament
How many actin filaments are maximally adjacent to each myosin filament?
How many myosin filaments are maximally adjacent to each actin filament?
6
3
How is melatonin in the pineal gland regulated?
Light strikes melanopsin, which signals to the suprachiasmatic nucleus that there is light. This causes the SCN to inhibit release of melatonin using sympathetic innervation.
Titan:
- Attachment points:
- Spring like portions location:
- Attachment points:
Attaches the Z line to the M line. - Spring like portions location:
I bands
Which sections of the sarcomere will shrink during contraction?
I zone. H zone (will disappear, which means actin runs into myosin)
Stroke cycle for myosin:
ATP binds causing myosin to release the actin filament
ATP is hydrolyzed which cocks the myosin head
The myosin head binds to actin
Pi is released, the power stroke begins, ADP is released, the stroke is over.
Rigor (the stroke is complete, the myosin is still attached, lowest energy state)
ATP binds repeat
Cross bridge:
The name he gives to the myosin protein extension which binds to actin.
How much do all cross bridges performing a single cycle contribute to muscle contraction?
move less then 1% of resting length.
Muscles can contract to 60% of their resting length
F-actin:
G-actin:
F-actin:
filamentous actin (polymerous G-actin)
G-actin:
A single actin monomer
Troponin:
- Attachment sites:
- Subunits:
- Attachment sites:
Tropomyosin - Subunits:
C, I, and T (C is the subunit to which Ca2+ binds)
Tropomyosin:
- Attachment sites:
- Attachment sites: attaches to both troponin and the F-actin (made up of G-actin)
What will happen in the absence of occlusion by troponin and the presence of actin?
Continuous cross bridges firing
Sydney Ringer showed what about muscle contraction?
He put rat hearts into isotonic solutions with hard water. Muscle contraction continued.
He showed muscle contraction did not continue in distilled water.
He also showed muscle contraction would continue if Ca2+ was added to water.
Sarcoplasm:
cytoplasm of a muscle cell
What type of transport concentrates Ca2+ within the sarcoplasmic reticulum?
Active transport (so Ca2+ cannot leave without ATP, and it cannot unbind without ATP, so it is needed for contraction and relaxation)
Are regions of the sarcoplasmic reticulum which run parallel to the transverse tubules (t tubules). Terminal cisternae are where Ca2+ is concentrated in the cell.
Terminal Cisternae:
How is Ca2+ released from the terminal cisternae of the sarcoplasmic reticulum of skeletal muscle?
Through ryanodine receptors (RYR1). Ryanodine is 10x larger than a voltage gated Ca2+ channel.
Are extensions of the sarcolemma which travel adjacent to the terminal cisternae. They motor potentials to be conducted throughout the muscle cell, and to depolarize the terminal cisternae.
Transverse tubules:
How does Ca2+ entry from the extracellular space occur?
voltage gated Ca2+ channels line the sarcolemma and T-tubules and they are activated by the voltage gated Na channels. These are DHP (dihydropyridine receptors)
How is activation of RyR1 receptors achieved?
DHP receptors (Ca2+ channels) in the transverse tubules are mechanically coupled to Ryanodine receptors in the terminal cisternae
What is the cause of hypokalemic periodic paralysis?
It is a channelopathy in your DHP receptors. A mutation which causes decreased sensitivity to voltage drops. When extracellular K+ levels are low the muscle repolarizes more quickly, which results in a paralysis when combined with the nonfunctioning DHP receptors.
What are people with hypokalemic disorder often misdiagnosed as?
Conversion disorder or hysterical paralysis (but it is not a psycholopathy)
RyR2 explain:
RyR2 is present alongside RyR1. RyR2 is voltage gated, and is activated by the change in Ca2+ conc. caused by the RyR1.
RyR2 is significant in its effect on the skeletal muscles, but it is the predominant cause of depolarization in the cardiac muscles.
Midbrain:
- Ventral tegmental area:
The ventral tegmental area is where the mesolimbic system starts
