Unit 4 Flashcards
Nervous System Main functions
1- sensory input
2-integration
3- motor output
CNS consists of
brain(cranial nerves send info) and spinal cord(spinal nerves send info)
PNS consists of
nerves and ganglia
sensory/afferent division sends signals
toward CNS
motor/efferent division sends signals
away from CNS
somatic nervous system contains voluntary control of
skeletal muscle
autonomic nervous system contains
-involuntary control of cardiac muscle, smooth muscle, and glands
-sympathetic (fight/flight) and parasympathetic (rest/digest)
supporting cells
glial cells/ neuroglia
astrocytes
chemical house keeping (in charge of what chemicals get in and out of capillaries)
microglial
defense cells
oligodendrocytes
myelinated CNS neuron axons
schwann cells
myelinated PNS neuron axons
ependymal cells
line brain and spinal cord
satellite cells
around neuron cell bodies in PNS
neurons
specialized cells that conducts messages in the form of electrical impulses
neuron trains
-amotoic
-extreme longevity
-high metabolic rate (require lots of O2)
dendrites
receiving branches of neuron, usually from another neuron to get excited or relax
soma/cell body
to recieve signals from dendrites and other cells, makes proteins and other large molecules (biosynthetic center)
axon/long fiber
send AP, some myelinated, some aren’t
axon terminal
knobs that secrete transmitter when AP arrives
functional classes of neurons
-sensory
-interneurons(CNS)
-motor(efferants)
structural classes of neurons
-multipolar neurons: lots of dendrites
-bipolar neurons: 1 axon and 1 dendrite
-unipolar neurons: 1 axon, no dendrites off soma
voltage
separation of charge= potential E
measured in mV
current (speed of flow, I)= Voltage (potential difference, V) / Resistance (how hard to get through, R)
describe leakage channels
always open, key for determining rest potential, located all over neuron (K+ leakage channels are most common)
gated channels
can be open/closed at any given time
chemically gated channels
opened by neurotransmitter
voltage gated channels
opened at preferred membrane potential