quiz #1 - review Flashcards
the nervous system branches into…
CNS (brain & spinal cord)
PNS
the peripheral nervous system (PNS) branches into…
autonomic (ANS): communicates with internal organs & glands
somatic (SNS): communicates with sense organs & voluntary mm
the autonomic nervous system (ANS) branches into…
sympathetic: “fight or flight”
parasympathetic: “rest & digest”
the somatic nervous system (SNS) branches into…
sensory (afferent): sensory input
motor (efferent): motor output
how many spinal & cranial nerve pairs
31 spinal nerves
12 cranial nerves
nervous system functional organization (3)
sensory
integrative
motor
types of neuroglia in the CNS
ependymal cells
oligodendrocytes
astrocytes
microglia
types of neuroglia in the PNS
satellite cells
schwann cells
Wallerian degeneration (PNS)
-after injury, “Wallerian degeneration” (demyelination) occurs
-schwann cells then multiply by mitosis, form regeneration tube
-tube grows length of axon
resting membrane potential
-70mV (inside more negative than outside)
= polarized
graded potential (communication)
short distance communication, varies in size of amplitude
action potential
long distance communication
3 factors that produce RMP
- unequal distribution of ions
- inability of most anions to leave cell (too large)
- electrogenic nature of Na+, K+, ATPase
4 types of ion channel gates
- leak channel (always open)
- ligand-gated (neurotransmitter, hormone, iron, etc.)
- mechanically gated (vibration, pressure, auditory, etc.)
- voltage gated (membrane potential)
graded potential
-arise in dendrites & cell body of neuron, do NOT travel down axon
-produce current, spreads to local regions then dies out
two graded potentials joined together
summation
3 possible outcome of summation
- EPSP: excitatory (may be big enough to trigger AP)
- IPSP: inhibitory
- action potential
2 types of summation
spatial: different location, same time
temporal: same location, different time
4 action potential phases
- depolarizing
- repolarizing
- hyperpolarizing (possible)
- refractory period (break)
depolarizing phase
-stimulus reach threshold
-voltage gated Na+ open, Na+ moves in
-potential reaches 0 then +, activates depolarizing phase
repolarizing phase
-Na+ channels close
-K+ channels open, K+ flows out
-membrane back to -70mV
hyperpolarizing phase
-K+ overflow out
-K+ channels close
-restore resting MP
2 types of propagation
continuous conduction: unmyelinated, slow
saltatory: “leap”, myelinated, fast, jump at nodes of ranvier
3 factors that affect speed of action potential
- amount of myelination: more = faster
- axon diameter: bigger = faster
- temperature: higher = faster
