collection of neuron cell bodies

- sensory ganglia

- house cell bodies of sensory neurons- pseudounipolar

- sensory for cranial nerves

- sensory for DRG

- send messages to the CNS 

- CNS relays it to the efferent neurons which act on the periphery 

-brain

-spinal cord

- sensory nerve fibers

- DRG

- autonomic ganglia 

- schwann cells

1. Anterograde: for nervous tissue synthesis @ the axon terminal; send vesicles to terminal

*slow-protein, actin microfilaments

*intermediate-mitochondria transported

*fast-synaptic vesicles

2. Retrograde: subunits of MT, building blocks of neurofilaments, molecules & protein destination for degradation

- 12

* 3-sensory

* 5- motor

* 4-mixed

31

-however, only 30 are sensory because the first cervical nerve is only motor

sER

mitochondria

microtubules (MT)

neurofilaments 

site where action potential takes place

-"spike trigger zone"

-nissl bodies

-site where there is a high concentration of rER & ribosomes (for protein synthesis)

-contains a euchromatic nucleus

1. Bipolar: sensation- eyes, ears, olfactory

2. Pseudounipolar: sensory ganglia- peripheral & central portions

3. Multipolar: motor nerve fibers & secondary ganglia in ANS

What are the 5 types of supporting cells of

nervous system?

-Oligodendrocytes-CNS

-Astrocytes-CNS

-Schwann cells-PNS

-Microglial cells-CNS

-Ependymal cells-CNS

- myelinated axon in the CNS

- can myelinate more than one axon

- myelin is the plasmalemma 

- from neural crest

-Produce myelin for the PNS

- only neuroglia that resides in the PNS

- from neural crest

- largest neuroglial cell/from neural crest

- has a high concentration of GFAP (glial fibrillar acidic protein)

- forms the scar tissue when a neuron dies

- act as blood-brain barrier

* perivascular foot=glia limitans

-grey=protoplasmic astrocyte (type 1)

-white=fibrous astrocyte (type 2)

Description of Microglial cells

- act like a phagocyte, clearing debris, & damage structures

- originates from bone marrow not neural crest

- elongated nucleus

- only glia cell not made from neruoblast

- lines the ventricles of the brain and central canal of the spinal cord

- secrets CSF

autoimmune disease against oligodendrocytes

Peripheral Nervous System

(describe)

-contain nerves, glanglia, 

-mexaxon=innermost & outermost lip of schwann cell

-schwann cells produce nodes of ranvier

* nodes of ranvier have no schwann cells

-where schwann cells have islands of cytoplasm

- a bubble from cytoplasm thats trapped in the schwann cell

Myelinated: saltatory conduction

>1 schwann cell per axon

>speeds up the conduction

>fibers have a major dense line & a intraperiod line

Unmyelinated: Continuous Conduction

>1 schwann cell for many axon

>slow speed of conduction

-external fibrous coat of dense C.T

-covers entire nerve

-surrounds each bundle 

-sleeve formed by layers of flattened epithelium

-contains tight junctions

-surrounds individual nerve fibers within each bundle

-composed of reticular nerve fibers

- house cell bodies of postganglionic autonomic nerves: multipolar neurons

***know what sympathetic and parasympathetic neurons do***

sympathetic: T1-L3 spinal nerves

- T1 in spinal cord

- T2 in sympathetic chain/collateral ganglia

parasympathetic: 4 cranial nerves & S2-S4 spinal nerves

-gray matter: unmylinated-neuron cell body & dendrites (dorsal, ventral, lateral horn)

-white matter: tracts that are myelinated

-cortex: grey mater over the brain

-nucleus: aggregation of cell bodies of neurons

-tract: aggregation of nerve fibers with same origins, end, course & function

1. Dura Mater: outermost, separated from arachnoid by thin subdural space

2. Arachnoid: intermediate, its space contains CSF & communicates w/ ventricles of the brain

3. Pia: innermost, highly vascularized, close contact w/ brain. Astrocytes glia limitan separates pia from the nervous tissue 

CSF (Arachnoid space)

-Complex of capillaries that only allow small molecules, & lipids to diffuse across

-allow glucose and AAs to pass via active transport

-fold of pia mater forms the choroids plexus within the plexus of the brain

- Normally Na is pumped out w/ H2O 

- Any decrease in pumping results in a high concentration of H2O in the ventricles and subarachnoid space

3 layes

1. molecular layer- basket cells

2. perkinje cell layer- pseudounipolar (large neurons)

3. granule cell layer- small neurons

1. neurons cannot regenerate in the CNS

-they are removed by macrophages 

-astrocytes repair causing a scar-gliosis

2. neurons are regenerated in the PNS

a. chromatolysis (changing in # of nissle bodies in soma)

b. Anterograde degeration

c. Schwann cell proliferation 

d. regeneration from the distal end

results if the axon cannot find the schwann cell cord