Chapter 10 - Muscle Tissue Flashcards
what are the 3 layers of connective tissue in skeletal muscle?
(outer to inner)
- epimysium (“upon the muscle”)
- perimysium (“around the muscle”)
- endomysium (“within the muscle”)
*these connective tissues come together at the ends of muscle to create tendons or aponeurosis
what are the layers of muscle structure?
(outer to inner)
- muscle (the rope)
- fascicle (the braids)
- muscle fiber: muscle cells. (the strings)
- have mitochondria
- multiple nuclei
- sarcolemma (cellular membrane)
- myofibril (the threads)
- sarcomeres
label the part of the muscle fiber
sarcomere
what are the thick and thin myofilaments of a muscle fiber called?
- actin (thin)
- myosin (thick) (myosin medusa heads)
*throughout the muscle fiber, think 3d.
what are the ends of the sarcomere?
z lines (zig zag lines).
*z lines come closer together during contraction
what are the membrane and fluid of muscle cells called?
- sarcolemma (membrane)
- sarcoplasm (fluid)
name the part of the muscle cell.
sarcoplasmic reticulum
- like the endoplasmic reticulum in other cells: the SER and the RER.
- for storage of energy
- walls are loaded with calcium pumps
what is the neurotransmitter that motor neurons release?
acetylcholine
name the parts of the model
- motor neuron, or muscle fiber, or muscle cell.
- axon
- neuromuscular junction = synapse + cleft
- synaptic cleft (the space where neurotransmitters are released and absorbed)
- sarcoplasm (the cytoplasm of the muscle cell)
- myofibrils (the threads of the muscle fibers, made of actin and myosin)
- sarcomere (the segment of z-line to z-line in each myofibril)
- nucleus
- sarcolemma (the cell membrane of the muscle cell)
- endomysium (the fibrous connective tissue around each fiber)
explain action potential at the neuromuscular junction.
- a motor neuron creates an action potential (electrical current) through to the neuromuscular junction.
- acetylcholine is released into the synaptic cleft from the action potential impulse.
- ACh binds to the membrane receptors on the sarcolemma and opens the sodium channels
- Sodium rushes though and creates an action potential in the sarcolemma
*acetylcholine is broken down by acetylcholine rase (AChE - enzyme), or diffuses.
what are the common properties of muscle tissue? (hint, there are 4)
- Excitability - responsiveness
- Contractility - ability to shorten
- Extensibility - ability to lengthen
- Elasticity - ability to recoil
what are the functions of muscle tissue?
- producing movement
- maintaining posture and body position
- supporting soft tissue
- guarding body entrances and exits
- maintaining body temperature
- storing nutrients
explain how a muscle fiber is created. what is the cell on the outside of the fiber called?
muscle fibers are made by the fusion of embryonic cells called myoblast cells.
*myosatelite cell is on the outside of the fiber
what are transverse tubules? (t-tubules). what do they do?
tubes that extend from the surface of muscle fiber into the sarcoplasm. they transmit action potentials from sarcolemma into the cell interior. action potentials trigger contraction
what is the storage net surrounding each myofibril?
the sarcoplasmic reticulum
what is the triad?
two terminal cisternae + t-tubule
what is titin?
elastic, spring like protein that connects end of myosin to the z line. helps stabilize the myosin filament and length
what is the section where the neuron and the muscle meet? what is the synapse space between these sites? what is the neurotransmitter released in this space? what does this neurotransmitter bind to?
- the neuromuscular junction
- the synaptic cleft
- acetylcholine (ACh)
