Ch. 9&11 Review Questions Flashcards
This consists of the axon terminal of a motor neuron and the motor end plate of a muscle fiber.
Neuromuscular junction
From what neuron do axons originate?
Motor neuron
This is a microscopic space separating an axon terminal from a muscle fiber.
Synaptic cleft
These are small membranous sacs filled with the neurotransmitter (ACh) acetylcholine in which they release.
Synaptic vesicles
This is a folded region of sarcolemma under the axon terminal. It contains ACh receptors.
Motor end plate
This breaks down ACh to prevent overstimulation of muscle fibers.
Acetylcholinesterase
This occurs when a neuron sends information down an axon away from the cell body. They are caused when different ions cross the neuron membrane.
Action Potential
During depolarization which ion is moving?
Na+
What is repolarization and which ion is moving?
Repolarization is restoration of the initial polarized state (resting membrane potential).
K+ ion is moving
This is a period where a cell cannot be stimulated again (usually during repolarization)
Refractory period
How does the action potential activate contraction (E-C coupling)?
Action potential spreads along the sarcolemma and down the t tubule.
Does ATP cause contraction or relaxation in the muscle fiber?
Relaxation
What is the motor unit?
A motor neuron and all the muscle fibers it supplies.
A muscle does not change in length but changes in tension with this type contraction.
Isometric
A muscle changes length but not in tension with this type of contraction.
Isotonic
What are the two types of isotonic contractions?
Concentric
Eccentric
With this type of isotonic contraction, muscle tension rises to meet the resistance but then remains stable as the muscle shortens.
Concentric
With this type of isotonic contraction muscle lengthens as the resistance becomes greater than the force the muscle is producing.
Eccentric contraction
This is an increase in the frequency with which a muscle is stimulated increases the strength of contraction.
Wave summation
This is rapid stimulation which creates sustained and quivering contractions. Incomplete.
Unfused tetanus
This is stimulation that is fast enough for all evidence of muscle relaxation to disappear. Complete.
Fused tetanus
This is multiple motor unit summation.
Recruitment
Motor units recruited in order from smallest muscle fiber to largest is called?
Size principle
What are the 3 pathways for regenerating ATP in muscle fiber?
- ADP and creative phosphate
- Glycolysis
- Aerobic respiration
This type of pathway for regenerating ATP uses no oxygen and it’s energy source is creating phosphate.
ADP and creatine phosphate
This type of pathway for regenerating ATP uses no oxygen and it’s energy source is glucose.
Glycolysis
This type of pathway for regenerating ATP uses oxygen and it’s energy sources include, glucose, pyruvic acid, free fatty acids from adipose, amino acids from protein catabolism.
Aerobic respiration
What 4 characteristics affect the force (strength) of muscle contractions?
- Number of muscle fibers stimulated
- Relative size of stimulation
- Frequency of stimulation
- Degrees of muscle stretch
What are the 3 muscle fiber types?
- Slow oxidative fibers
- Fast oxidative fibers
- Fast glycolytic fibers
This type of muscle fiber is slow in duration and velocity and are red.
Slow oxidative fibers
This type of muscle fiber is fast in velocity and contraction and is white.
Fast oxidative fibers
Fast glycolytic fibers
What are the 2 layers of smooth muscle tissue?
- Longitudinal- long axis of organ
2. Circular- circumference of organs
What movement do the 2 layers of smooth muscle tissue produce?
Peristalsis
How does activation of smooth muscle differ from skeletal muscle?
Smooth muscle has
- no neuromuscular junctions
- no sarcomeres
- the nerve endings end in varicosities
How do the myofilaments differ in smooth muscle?
Smooth muscle has myosin heads along the entire length and can form additional cross bridges and latch on to actin.
How does contraction differ in smooth muscle vs skeletal muscle?
Smooth muscle has gap junctions which tell one to contract then sends signal to the next all the way down a line. Example small intestine.
What mechanism controls smooth muscle contraction?
Neural
Hormones and local factors
Smooth muscle can adapt to new lengths and still contract on demand. There is no sarcomeres you can stretch and release and will go back to its original self. It is more flexible and responsive than skeletal. This describes what?
Stress-relaxation response
This is the ability of smooth muscle cells to divide and increase their numbers.
Hyperplasia
What are the 2 types of smooth muscle tissue?
- Single unit visceral
2. Multiunit smooth muscle
This type of smooth muscle tissue the cells contract rhythmically and together as a unit.
Single unit visceral
This type of smooth muscle tissue has muscle fibers that are structurally independent and have many nerve endings. Their response to neural stimulation is graded (recruitment).
Multi-unit smooth muscle