Exam 3 Flashcards
What is a muscle twitch?
a quick cycle of contraction when stimulus is at threshold
What is anaerobic fermentation?
enables cells to produce ATP when there is no oxygen around
What is aerobic respiration?
produces more ATP than anaerobic and requires oxygen
What is a slow twitch?
smaller and is more resistant to fatigue
What is a fast twitch?
larger and has a poor fatigue resistance
What are the 6 sources of muscular fatigue?
- ATP synthesis
- Less effectiveness of sodium potassium pumps
- Lactic acid build up
- Motor neurons using up ACh
- Potassium diffusion
- Weaker central nervous system
What are sensory neurons?
Afferent– Receive stimuli from environment and transmits to CNS
What are motor neurons?
Efferent– receives stimuli from CNS and transmits to body
What do interneurons do?
connect the sensory and motor neurons
What is a neuron?
A nerve cell
What is a nerve?
A bundle of nerve fibers
What is a ganglion?
A knot-like swelling nerve
What does the Central Nervous System consist of?
Brain and spinal cord
What does the Peripheral Nervous System consist of?
Everything except brain and spinal cord
What are the three divisions of the autonomic nervous system?
visceral, sympathetic, and parasympathetic
What are multipolar neurons?
one axon and many dendrites
What are bipolar neurons?
one axon and one dendrite
What are anaxonic neurons?
No axon and many dendrites
What are neuroglia?
Protect and aid neurons
What are the 6 types of neuroglia?
oligendrocytes, astrocytes, ependymal cells, microglia, schwann cells, and satellite cells
What do oligodendrocytes do?
Create myeline sheath
What do astrocytes do?
cover brain surface
What do ependymal cells do?
line internal cavities
What do microglia do?
consume debris in central nervous system
What do schwann cells do?
create myelin sheath
What do satellite cells do?
surround soma of neurons
Why is myelin important?
insulates the nerve fiber
What are the 3 steps of an axon regeneration?
- consumed by macrophages
- axon stump grows sprout
- regeneration tube guides prout
What is resting membrane potential?
polarized membrane due to high conentration of anions outside and cations inside
What is local potential?
When a dendrite receives neurotransmitters
What is action potential?
When local potential reaches trigger zone
What is the refractory period?
Period of resistance to stimuli
What is a synapse?
Junction between neuron and target cell
What are the 4 forms of neurotransmitters?
acetylcholine, amino acids, monoamines, and neuropeptides
What are the 3 steps involved in cholinergic synaptic transmissions?
- action potential arrives
- calcium ions enter synaptic knob
- empty vesicles retreat into cytoplasm
What is ionotropic effect?
neurotransmitter opens ion gates and changes membrane potential
What is metabotropic effect?
Neurotransmitters alter metabolism to creat cAMP
What are the 3 means of removing neurotransmitters?
diffusion, reuptake, and degradation
What is EPSP?
Excitatory postsynaptic potential?
What is IPSP?
Inhibitory postsynaptic potential?
What is summation?
Responding to the net effect of postsynaptic potential
What is temporal summation?
One single synapse generated quickly to get to threshold
What is Spatial summation?
several synapses generate threshold
What is qualitative information?
which neurons are firing
What is quantitative information?
how many neurons are firing
What are the three meninges?
Dura metter (most superficial), arachnoid mater, and pia matter (deepest)
How many spinal nerve pairs are there?
31
What are the 4 structures of the spinal chord?
cervical, thoracic, lumbar, and sacral
What is the ascending tract?
carry info up spinal chord to brain
What is the descending tract?
carry info down spinal cord to body
What are the 3 functions of cerebrospinal fluid?
buoyancy, protection, and chemical stability
Where does cerebrospinal fluid come from?
fuels external surfaces of the central nervous system
Why is it important to keep whole blood from touching the central nervous system?
to prevent toxins from entering
Whats the blood-brain barrier?
found in capillaries in brain tissue
What is the blood CSF barrier?
formed by junctions between ependymal cells
What are the 5 plexuses?
cervical, bracial, lumbar, sacral, and coccygeal
What are proximal branch of the spinal nerve?
spinal nerves have 2 points of attachment
What are the distal branches of the spinal nerve?
spinal nerves have 3 branches
Whats a dermatome?
areas of skin that send sensory info
What are the 4 characteristics of reflexes?
stimulation, quick, involuntary, and stereotyped
What type of neurons are found in the roots of spinal nerves?
interneurons
What does ipsilateral mean?
on the same side of the body
What does contralateral mean?
on opposite sides of the body
What are the 4 steps of contraction?
- Active sites exposed, ATP binds to myosin heads. Myosin ATPase in head break down ATPADP and phosphate group. Myosin head moved into extended starting position
- Myosin head binds to active site on actin filament/ forms a cross bridge.
- Myosin releases ADP/ Phosphate group. Head flexes to bent position, drags actin filament with it (power stroke). Stays bound with actin till new actin molecule binds with head.
- ATP binds with myosin head, breaks bond between actin/myosin. Myosin ATPase breaks ATPADP/ phosphate group. Returns to extended position (recovery stroke). Steps 2-4 repeat.
What are the 5 steps of relaxation?
- Nerve signals stop stimulating neuromuscular junction and the synaptic knob stops releasing Ach.
- AChE breaks down ACh and the Ach receptors close their gates. Synaptic knob reabsorbs the Ach fragments for recycling. Action potentials stop and stimulus to contract the muscle cells stops.
- Active transport pumps in sarcoplasmic reticulum return calcium ions from cytosol to terminal cisternae. ATP is required to relax muscle fibers.
- Calcium is removed from troponin and pumped back into SR.
- Troponin-tropomyosin complexes cover active sites of actin again. Myosin can no longer bind to actin; muscle fiber loses tension and returns to resting length due to titin, tendons, and muscles.
