Chapter 12 Flashcards
Function of nervous system
Maintaining homeostasis
Homeostatic mechanism
1: sensor (sensory)
2: control center (inter)
3: effector (motor)
Two branches of the nervous system
Central nervous
Peripheral nervous
Sections of the CNS
Brain
Spinal cord
(Interneurons)
Sections of the PNS
Sensory
Motor
Sections of motor
Somatic- voluntary
Autonomic- involuntary
Different autonomic
Parasympathetic- rest and digest
Sympathetic- fight or flight
Soma
Cell body
Dendrites
Receptors at the end of soma
Axon
Tail of cell
Axon hillock
Axon attaches to soma
Telodendria
Tail end of axion
Axon terminal
At the ends of the teledendria
Myelin sheaths
Cell like structure on axon
Nodes of ranvier
Spaces between myelin sheaths
Sensory neurons
Delivers information from receptors to the CNS
Motor neurons
Carry instructions from CNS to muscles
Interneurons
In the CNS, over 90% of neurons
Unipolar neurons
Off to the side of the axon
Multipolar
Single axon multiple dendrites
Neuroglia
Supportive cell, helps with protection and function
Astrocytes
CNS, blood brain barrier
Ependymal cell
CNS, cerebral spinal fluid
Oligodendrocyte
CNS, Wraps around axon to make sheaths for protection
Microglia
CNS, immune function
Schwann cell
PNS, wraps around axon for protection
Satellite cell
PNS, Regulates environment around neurons
Blood brain barrier
Regulates chemicals in circulation, protect neural tissue
What are myelin sheaths made of
Lipids
Resting membrane potential
A neuron has not been stimulated -70mV
Where to the ions rest?
Na+ rests outside
K+ rests inside
Sodium potassium pump
Returns Na outside and K inside 3:2
Threshold
Bring membrane to -60mV
Depolarization
1, Na+ enters the cell
Peak potential
Top of the graph +30mV
Repolarization
2, K leaves the cell
Hyperpolarization
3, down to -90mV, gates shut
Refractory period
Cell cannot be stimulated
Step 4
Sodium potassium pump puts ions back 3Na:2K
Saltatory conduction
Increase speed of AP by allowing it to skip over sections of axon
Excitatory
Promotes AP, depolarization
Inhibitory
Decreases AP, hyperpolarization
Norepinephrine/ epinephrine
Cardiac contraction
Acetylcholine
Contracts skeletal muscle, inhibits cardiac
Melatonin
Helps with sleep
GABA
Calming
Temporal summation
Repeated stimulation
Spatial summation
Multiple signals at once