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what is the PNS broken down into
sensory (afferent) and Motor (efferent)
- Afferent=toward origin
- efferent=away from origin
what is the afferent division broken into
- the sensory division is broken into
- 1) somatic sensory: carries signals from skin, musckes, bones, & joints.
- 2) Visceral sensory: carries signals from thoracic and abdominal cavities.
What is the efferent division broken into
- the motor division is broken into
- 1) somatic motor: carries signals to the skeletal muscles
- 2) visceral motor (ANS): carries signals to glands, cardiac and smooth muscles
what are the divisions of the visceral motor division
- the involuntary ANS is broken down into
- 1) sympathetic: arouse, but inhibits indigestion.
- 2) parasympathetic: calming, but stimulates digestion.
1) cranial nerve 1 is for?
2) cranial nerve 2 is for?
3) cranial nerve 3 is for?
4) cranial nerve 4 is for?
5) cranial nerve 6 is for?
- 1) olfactory: smell
- 2) optic: vision
- 3) oculomotor: eyeball and upper eyelid
- 4) trochlear: eyeball movement
- 5) abducens: eyeball movement
1) cranial nerve V is for?
2) cranial nerve VII is for?
3) cranial nerve VIII is for?
- 1) trigeminal:facial sensation, chewing
- 2) facial: facial expression, 1st (1/3) of tongue
- 3) 8 vestibularcochlear: hearing
1) cranial nerve IX is for?
2) cranial nerve X is for?
3) cranial nerve XI is for?
4) cranial nerve XII is for?
- 1) 9 glossenpharyngeal: taste, speach
- 2) 10 vagas: taste, caughing, voice, heart rate
- 3) accessory: swallowing, head/shoulder movement
- 4) hypoglossal: tongue and swallowing movement
What does afferent and efferent mean
- Afferent/sensory: inward to source
- efferent/motor: outward from source
cluster of nerve cell bodies in the PNS, often resembling a knot in a string
A ___ is a collection of nerve fibers in the PNS, unsheathed (held together) in connective tissue.
list 2 kinds of nerve cells
neuroglia and neurons
what's the control center of a neuron called
Soma, AKA: neurosoma/cell body.
Why don't neurons replicate themselves
they have no controls, so they are amitotic.
What is an impulse?
Change in electrical potential conducted along a plasma membrane.
how are impulses transmitted?
by a chain reaction of ions flow along electrochemical gradients.
1) Explain resting membrane potential?
1) More Na+ outside the membrane and More K+ inside. Ions flow down gradient when channels open.
2) The relative ion concentrations give the cell a -70mV charge
voltage shifts to a less negative value is called. Toward more positive numbers.
what needs to happen for local potential to open voltage gated channels?
Potential must rise to the Threshold (-55mV).
what causes the voltage to reach a peak?
- -voltage gated Na+ channels open (at the trigger zone/axon hillock)
- allowing a positive feedback loop of Na+ influx, which pushes potassium (K) out. Peaking at 35+
When do voltage gated channels begin to close during an action potential
Channels begin to close when voltage reaches 0.
What happens after the action potential peaks?
Repolarization: Potassium gatted channels are opened, so potassium leaves the cell decreasing voltage back to negative.
What happens after repolerization
-hyperpolarization: K channels close slower, so more K leaves than Na that entered dropping voltage below 70mV.
-The sodium potassium pump removes 3Na, and brings in 2K, consuming 1ATP.
How do action potentials move all the say down an axon
Na ions migrate down the axon, and the nodes of Ranvier allow more Na inflow to maintain action potentials.
What are the nodes of Ranvier
gaps between myelinated segments of an axon.
2 factors that influence the rate of impulse propagation
- 1) axon diameter: larger diameter=faster
- 2) Mylin Sheath: faster & less energy
what enables the action potential to be regenerated along an axon?
saltatory conduction opens Na channels between myelinated axons at the nodes of Ranvier.