Term
- Produce Skeletal Movement
- Maintain Posture and Body Position
- Support Soft Tissues
- Guard Entrances and Exits
- Maintain Body Temperature
- Store Nutrient Reserves
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Definition
What are the functions of skeletal muscles
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Term
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Definition
T/F: The entire muscle is surrounded by the perimysium.
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Term
False: A dense layer of collagen fibers
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Definition
T/F: Epimysium is composed of elastic connective tissue.
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Term
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Definition
The connective tissue that separate adjacent fascicles is called what?
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Term
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Definition
Term for the connective tissue that surrounds the individual skeletal muscle cell.
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Term
Tendon or Aponeurosis (broad sheets)
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Definition
The combination of the collagen fibers of the epimysium, perimysium and endomysium at each end of the muscle forms ________ or ________.
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Term
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Definition
The plasma membrane of a muscle fiber.
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Term
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Definition
Cytoplasm of the muscle fiber
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Term
T Tubules or Transverse Tubules
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Definition
These are narrow tubes that are continuous with the sarcolemma and extend into the sarcoplasm at right angles to the cell surface.
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Term
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Definition
T tubules are filled with ____________.
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Term
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Definition
Repeating functional units of muscle cells
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Term
- M Line – Central portion of thick filaments
- H Band – Thick filaments but no thin filaments
- Zone of Overlap – Each thick filament is surrounded by six thin filaments
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Definition
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Term
Contains thin filaments but no thick filaments
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Definition
What Characterized the I Band
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Term
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Definition
These mark the boundary between adjacent sarcomeres. These consist of proteins call actinins, which interconnect thin filaments of adjacent sarcomeres.
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Term
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Definition
Stands of elastic protein extend from the tips of the thick filaments to attachment sites at the Z line.
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Term
5-6 nm in diameter and 1 mm in length.
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Definition
What are the dimensions of a typical thin filament?
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Term
4 proteins
F-actin
nebulin
tropomyosin
troponin
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Definition
How many proteins make up the thin filament? Name them.
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Term
Strands of tropomyosin cover the active sites on G-actin.
(At the beginning stages of contraction Ca2+ binds to troponin, which causes a conformational change that allows tropomyosin to be moved deeper in the groove of the actin dimer.)
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Definition
Where are the active sites for connection with myosin heads and what covers them during relaxation?
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Term
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Definition
How many stands of G-actin make up F-actin?
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Term
10-12 nm in diameter and 1.6 mm in length
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Definition
What are the dimensions of thick filaments?
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Term
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Definition
Approximately, how many myosin molecules comprise a thick filament?
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Term
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Definition
| T/F: When the myosin heads interact with thin filaments during a contraction, they are known as cross-bridges. |
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Term
During contraction:
- H bands and I bands get smaller
- the zones of overlap get larger
- the Z lines move closer together
- the width of the A band remain constant
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Definition
| What are observations that lead to the sliding filament theory? |
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Term
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Definition
| The nuerotransmitter that is released by the axon of the nerve that transverses the synaptic cleft and stimulates contraction in muscle cells |
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Term
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Definition
| What enzyme breaks down acetylcholine and is held in the synaptic cleft and the sarcolemma? |
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Term
| the cisternae of the sarcoplasmic reticulum. |
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Definition
| Where is Ca2+ released from in the early stages of muscle contraction? |
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Term
- Ca2+ entering the sarcoplasm bind to troponin and expose active sites on actin.
- Formation of cross-bridges
- Pivoting of myosin heads (power stroke); ADP and pi are released
- ATP binds to myosin head, breaking the cross-link
- Recocking of the myosin head by hydrolysing ATP to ADP + pi
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Definition
| What are the basic steps in the contraction cycle |
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Term
| Whithin a few hours, the skeletal muscle fibers have run out of ATP and the sarcoplasm retains Ca2+. Calcium triggers a sustained contraction, where myosin cannot detach as there is no ATP. Therefore, skeletal muscles throughout the body become locked in the contracted position until enzymes can break down the Z lines and titin filaments. |
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Definition
| Pathophysiology of Rigor Mortis |
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Term
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Definition
| Each power stroke shortens the sarcomere by what percentage? |
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Term
| are under involuntary control |
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Definition
| Smooth muscle and cardiac muscle are similar in that they both |
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Term
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Definition
| Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the |
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Term
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Definition
| The region of the sarcomere that contains both actin and myosin myofilaments is called the |
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Term
Which of the following is mismatched?
A. I band - contains only actin
B. M line - middle of the H zone
C. Z disk - structure between adjacent sarcomeres
D. myosin myofilaments - thin myofilaments
E. actin myofilaments - thin myofilaments
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Definition
Which of the following is mismatched?
A. I band - contains only actin
B. M line - middle of the H zone
C. Z disk - structure between adjacent sarcomeres
D. myosin myofilaments - thin myofilaments
E. actin myofilaments - thin myofilaments
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Term
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Definition
| Which molecule on the thin filament has a calcium binding site? |
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Term
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Definition
| These conduct action potentials deep into the muscle cell |
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Term
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Definition
| The outside of the resting plasma membrane is __________ relative to the inside of the resting plasma membrane. |
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Term
there are more non-gated channels for K+ than Na+.
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Definition
| The plasma membrane of an excitable cell is more permeable to potassium ions because |
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Term
| calcium ions diffuse into the presynaptic terminal through voltage-gated ion channels |
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Definition
| When an action potential reaches the presynaptic terminal, |
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Term
| continuous stimulation of the postsynaptic membrane |
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Definition
| Lack of acetylcholinesterase in the synaptic cleft would result in |
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Term
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Definition
| Acetylcholine is released from the presynaptic terminal by the process of |
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Term
| rapid degredation of acetylcholine |
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Definition
| Too much acetylcholinesterase causes |
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Term
| inability of the muscle fiber to respond to nervous stimulation |
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Definition
| Curare blocks acetylcholine receptors at the motor end plate. This would result in |
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Term
| on the postsynaptic membrane |
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Definition
| Where does a neurotransmitter bind with a receptor molecule? |
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Term
| the active sites on actin must be blocked |
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Definition
| In order for muscle relaxation to occur, |
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Term
| contraction with no relaxation |
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Definition
| A drug that interferes with the active transport of calcium ions from the sarcoplasm back into the sarcoplasmic reticulum would result in |
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Term
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Definition
| A sustained muscle contraction is known as |
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Term
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Definition
| During resting conditions, _________ is synthesized to store energy? |
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Definition
| yields as many as 38 ATP per glucose molecule metabolized |
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Term
A. actin filament
B. myosin filament
C. Cross-bridge
D. Z-disk
E. Sarcomere |
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Definition
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Term
| Blocking calcium ion channels would prevent the diffusion of calcium ions into the presynaptic terminal. Calcium ions in the presynaptic terminal cause synaptic vesicles to release neurotransmitters. Therefore, release of neurotransmitters would be blocked, or at least reduced, and that could result in failure of the action potential to be transmitted across the neuromuscular junction |
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Definition
| Predict the consequences of the administration of a compound that blocks the calcium channels on presynaptic terminals |
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Term
| If a compound binds to the acetylcholine receptors, then acetylcholine cannot bind to the receptors and the muscle will not be able to contract. This is a condition called flaccid paralysis. |
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Definition
Predict the consequences the administration of a compound that binds to acetylcholine receptors
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Term
| If the action of acetylcholinesterase is inhibited, acetylcholine is not degraded and would accumulate in the synaptic cleft and act as a constant stimulus to the muscle fiber. The muscle cells will continue to contract resulting in a condition called spastic paralysis. |
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Definition
| Predict the consequences of the administration of a compound that inhibits acetylcholinesterase |
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Term
| The botulism toxin would be a competitor for the neurotransmitter receptor sites on the postsynaptic membrane. If the toxin occupies these receptor sites, the neurotransmitter cannot attach to the receptor sites and the muscle cell is unable to respond to an action potential. The muscle is paralyzed. |
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Definition
| Botulism food poisoning results from a toxin (poison) produced by bacteria. Death from botulism results from relaxation of the respiratory muscles (diaphragm). Assuming that this toxin affects the neuromuscular junction, propose a way in which this toxin could cause these muscles to relax and no longer contract. |
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