The Nervous System

Dendrites

where impulses are received from synapses

cell body/soma

central part of the neuron containing the nucleus an organelles

collections of cell bodies are call

grey matter

axon 

the elongated portion of the cell when sends electrical nerve impulses down the neuron from dendrite to the axon terminal 

collections of axons are called…

white matter

axon terminal

the end of a neuron which sends other signals to neuron’s by releasing neurotransmitters

Collections of axons in the CNS

tracts

collections of axons in the PNS 

nerves 

collections of cell bodies in CNS

nuclei

collections of cellbodies 

ganglia

cervical region

neck- 7 vertebrate

throatic region

chest 12 vertebrae

lumbar region

back below chest 5 vertebrate

sacral reigon

lower back 5 vertebrate

coccygeal reigon

tail 3-5 vertebrate

subsections of the peripheral nervous system:

1. somatic nervous system

2. autonomic nervous system

somatic nervous system

controls voluntary actions, like walking, and conscious sensory input from the skin and muscles.

autonomic nervous system

manages involuntary, internal body functions, such as breathing, heartbeat, and digestion, working without your conscious thought.

2 subsections of the autonomic nervous system

1. parasympathetic nervous system

2. sympathetic nervous system

parasymapthic nervous system

‘rest and digest’

sympathetic nervous system 

“fight or flight”

afferent nerves

Carries sensory information towards the CNS

Efferent nerves

carries motor information from the CNS to the PNS

Impluses in the ANS efferent nerves are passed through…

ganglia before reaching the target organ

parasympathetic ganglia are…

near the target organ 

sympathetic ganglia are…

near the spinal cord

parasympathetic nerves originate from…

1. the brain (12 cranial nerves)

2. sacral region (lower back)

symapathetic nerves originate from…

1. thoracic region (chest)

2. Lumbar region (back below chest)

Each organ receives info from both the SNS and PSNS though these messages…

act in an opposing fashion to one another (one tells to turn on the other tells to turn off)

How many pairs of spinal nerves are there?

31 pairs

how many pairs of cranial nerves are there?

12 pairs (that originate from the brain)

while there are still axons, the lower half of the spine does not have…

gray matter

Vagus nerve

the largest and primary cranial nerve of the parasympathetic nervous system (sends signals to almost all vital organs)

cranial nerves range from

rostral - caudal

most cranial nerves are mixed between…

sensory and motor infomations

cranial nerves are mixed b/t sensory and motor because….

sensory information is crucial to the brain knowing where the moving body part is in space