Lecture 9 -Nervous Flashcards
2 core divisions of the nervous system
Central nervous system and the peripheral nervous system
what makes up the central nervous system and what is it derived from?
brain and spinal cord. derived from the neural tube
what makes up the peripheral nervous system and what is it derived from?
all nervous tissues outside of the CNS. Derived from neural crest cells
What are the 3 primary functions of nerve cells?
Irritability (speed of response), conductivity (transmit a response), and secretion (neurotransmitters)
Glial cells
support and protect neurons. Formed from monocytes.
Afferent system
receive and transmit information from the environment to the CNS
Efferent system
Transmits info from the CNS to the periphery (exiting from the CNS)
3 main types of neurons
bipolar, multipolar, and pseudounipolar
Most common type of neuron
multipolar
Bipolar
two dendrites, found in retina, cochlear, and olfactory
Multipolar
Lots of dendrites. Most commonly found
Pseudounipolar
Cell body is down the axon terminal. Found in long neurons, such as the dorsal root ganglia.
Afferent neurons primarily are what type of neuron?
Pseudounipolar
Somatic vs autonomic
somatic: voluntary muscles
autonomic: involuntary smooth muscles (both parasympathetic and sympathetic)
Interneurons
coordinate all neural activities and consist of mostly multipolar neurons.
Myelinated neurons in PNS
myelin sheath formed by schwann’s cells (roll themselves around the axons).
Myelinated neurons in CNS
myelination formed by glial cells or oliogodenrocytes
Non-myelinated neurons
Also have schwann cells present but do not roll around axons. Primarily used for support
Cholinergic neurotransmitter
acetylcholine. Most efferent nerves
Adrenergic neurotransmitter
norepinephrine. Postganglionic sympathetic neurons
Perikaryon
cell body around the nucleus
Dendrite
short processes that receive the stimuli. Lack golgi.
Synapse
connection of the dendrite
Collateral branch
when some of the axons get branched. Have terminals which make the connection with the next cell