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Bio 104 Chapt 4
Muscle Tissue
Question | Answer |
---|---|
Composed of fibers that contract, causing movement.Three types:Skeletal, Smooth, Cardiac. | Muscle Tissue |
The cell membrane surrounding each muscle fiber | Sarcolemma |
Several muscle fibers bundled together, separated by endomysium | Fasciculus |
Connective tissue that separates muscle fibers in a fasciculus | Endomysium |
Connective tissue that surrounds a muscle | Perimysium |
A layer of fibrous connective tissue outside the epimysium that separates individual muscles | Fascia |
The specialized nerve cells that deliver an impulse to the muscle cell, causing it to contract | Motor neurons |
The junction between a motor neuron and a muscle fiber | Neuromuscular Junction/Synapse |
The portion of the neuromuscular synapse at the distal end of the nerve fiber | Presynaptic terminal |
Portion of the neuromuscular synapse at the proximal portion of the muscle fiber | Postsynaptic terminal |
Lies in a space in the neuromuscular junction, between the nerve and muscle. Space across which a nerve impulse is transmitted | Synaptic cleft |
A change in electrical potential that occurs when a cell or tissue has been activated by a stimulus | Action Potential |
The _________ ___________contains numerous synaptic vesicles that contain the chemical acetylcholine, which functions as a neurotransmitter | presynaptic terminal |
A substance that transmits nerve impulses across a synapse | Neurotransmitter |
The movement of the vesicles is stimulated by the influx of calcium (Ca2+) ions into the _____________ nerve terminal | presynaptic |
Once it crosses the ____________cleft, acetylcholine causes an increase in the muscle membrane's permeability, allowing sodium (Na+) ions to diffuse into the cell via special protein ion channels, producing an electrical change | synaptic |
During muscle contraction, the ___________ shorten as the actin myofilaments slide over the surface of the myosin | sarcomeres |
This occurs when calcium is actively transported back into the sarcoplasmic reticulum | Muscle Relaxation |
Muscle contraction requires energyThe main source of energy for muscle contraction in the body is _____, which can be converted to ______ | ATP, ADP |
An organic acid that can lower the intracellular pH | Lactic acid |
An iron-containing pigment found in red blood cellsCarries about 97% of the oxygen in the body | Hemoglobin |
An iron-containing red pigment found in muscle fibers | Myoglobin |
What is made up of spindle-shaped cells with a single nucleus. Smaller than skeletal muscle cells. The cells contain fewer actin and myosin myofilaments than skeletal muscle cells. Myofilaments are not organized into sarcomeres | Smooth Muscle |
Sheets of muscle that form the layers of the digestive, reproductive, and urinary tracts | Visceral smooth muscle |
______ muscle contraction is involuntary | Smooth |
A cell at rest, waiting to react to a stimulus | Polarized cell |
Requires a trigger or minimum energy levelResults in the opening of channels, allowing sodium to rush in.An action potential fires, stimulating surrounding cells | Polarized cell |
The unique ability of cardiac muscle to generate its own electrical activity | Intrinsic automaticity |
The recovery phase, Sodium leaves the cell, Cell returns to a polarized state | Repolarization |
End of a muscle that is attached to the more stationary of two bones | Origin (head) |
End attached to the bone undergoing the greatest movement | Insertion |
Largest portion of the muscle, between the origin and the insertion | Belly |
Tough, ropelike cords of fibrous tissue that attach muscles to bone | Tendons |
Muscles that work together to accomplish a particular movement | Synergists |
Muscles working in opposition to other muscles | Antagonists |
When a group of muscles is involved in a movement, this is the muscle that plays the major role in accomplishing the task | Prime mover |
Muscles that stabilize the origin of the prime mover | Fixators |