chapter 12 nervous system janna

nervous system

communication, storing and processing info, and coordinating the body's responses to internal and external stimuli.

how many cranial nerves

12 pairs

how many spinal nerves

31 pairs

somatic motor

division responsible for voluntary muscle control.

autonomic moor

division responsible for involuntary control of smooth muscles and glands. takes info away from central nervous system

afferent division

the part of the nervous system that transmits sensory information to the central nervous system. somatic, visceral, special

special sensory

refers to the sensory pathways that convey information from specialized receptors for taste, hearing, vision, smell, and balance to the central nervous system.

somatic sensory

refers to the sensory pathways that transmit sensations from the skin, muscles, and joints to the central nervous system, allowing for the perception of touch, pain, temperature, and proprioception.

visercal sensory

refers to the sensory pathways that transmit information from internal organs, such as the heart and digestive system, to the central nervous system. This includes sensations of hunger, thirst, and visceral pain.

neurons

nerve cells, conductivity secretion, last for ever, once broken can’t be repaired, use lots of ATP, uses lots glucose

nucelus

cluster of cell bodies inside the nervous system

ganglia

cluster of cell bodies in peripheral system 

tracts

cluster of axons in central nervous systems

nerve

cluster of axons in peripheral nervous system

glial cells

support cells, can replicate, support neuronsand maintain homeostasis in the nervous system.

astrocyte

blood brain barrier to protect neurons

oligiodendrocytes

wrap around axon to make myelin sheets

ependymal cells

created cerebral spinal fluid

microglia

removes waste

myenfilation

increase action potential, speed, electrical isolation, and is made of fat.

nodes of raviner

naked gaps areas within the axon, action potentials can jump over them

voltage

voltage the cell membrane provides separation of changes

resting membrane potential

at rest, inner cell is negative while outer cell is positive

resting action potential

-70mv

permeable to sodium is

60mv is the threshold for action potential generation.

permeable to potassium is

-90mv, the level at which potassium ions will flow out of the cell.

cell is permeable to both sodium and potassium, but it is more permeable to

POTASSIUM!

cells moving through a membrane need…

a voltage gated channel

local potentials

produced by non voltage gated channels, happens in cell body and dendrites, causes bigger mV change

action potentials

rapid spike in membrane, always generated by voltages. starts at axon hillock and down the axon. DEPOLARIZING. can’t be reversed or summate

simulus process

1. non voltage gates opens

2. local potential summates

3. threshold is reached -55mv

4. voltage gates open

5. generate action potential

refractory periods

period of time when difficult to generate another action potential