Nerve Tissue

Question 1

Organization of nerve tissue

Answer 1

CNS - brain and spinal cord
PNS - cranial and spinal nerves
ANS - controls gland secretion…cell bodies found in CNS while process and postganglionic bodies in the PNS

Question 2

Composition of PNS and CNS

Answer 2

Both have neurons and supporting cells

CNS - uses neurolgia…divided into Gray and White matter

PNS - Schwann and satellite cells…divided into ganglia and nerves

Question 3

Gray and white matter

Answer 3

Gray - neuron cell bodies and neuoglia…unmyelinated…astrocytes

White - neuronal processes and neuroglia…myelinated…astrocytes and oligodendrocytes

Question 4

Gnaglia and nerves

Answer 4

Ganglia - neuron cell bodies, schwann and satellite cells

Nerves - axons, dendrites and schwann cells

Question 5

Strutcture of a neuron

Answer 5

Nucelus - owl’s eye with dark nucleolus
Nissl substance - RER
Axon hillock - lacks nissl substances and cytoskeletal elements funnel into axon from cell body

Question 6

Dendrite

Answer 6

Multiple places for synapse…rarely myelinated

Question 7

Dendritic spines

Answer 7

Receive synapses (input) toward the cell body

Question 8

Types of neurons and where found

Answer 8

Bipolar - special sense (except taste)…one of each
Multipolar - motor (both vaso and somato)…one axon and multiple dendrites
Psuedounipolar - sensory…have fused axon and dendrite

Question 9

Schwann cells (myelination of the PNS)

Answer 9

Schwann cell membrane provides the myelin sheath of the axon…mesaxon where invagination occurs

Question 10

In the PNS

Answer 10

One schwann cell myelinates ONE internode of ONE neuronal process

Question 11

Node of ranvier (and what is in the CNS)

Answer 11

SC cytoplasm is what covers here…no SC membrane

In the CNS, astrocytic end-foot

Question 12

CNS myelination

Answer 12

One oligodendrocyte myelinates ONE internode on as many adjacent neuronal process as the oligodendrocyte has processes

Question 13

unmyelination of the PNS

Answer 13

Axons arranged in circular pattern around the nucleus…SC cytoplasm surrounds entire thing with each axon having one layer of SC membrane around it

Question 14

Terminal buttons are made of

Answer 14

Schwann cell cytoplasm

Question 15

Types of synapses and most common

Answer 15

Axosomatic (terminates on soma of the neuron)
Axoaxonic
Axodendritic**
Axospinous

Question 16

Morphology of the synapse

Answer 16

Can see presynaptic vesicle and post synaptic thickening

Vesicles travel down MT tract

Question 17

Major trnasmittors of the CNS and which are excitatory and inhibitory

Answer 17

AA
Ex - glutamate; cortex, basal gang, thalamus, cerebellum

In - GABA; cerebellum, basal ganglia and glycine; lower brainstem (medulla) and spinal cord

Question 18

Amine NTs

Answer 18

dopamine
NE
Serotoninn

Question 19

Ach

Answer 19

Used by cranial nerve motor nuclei (nucleus ambiguus, hypoglossal, DMV)
Spinal cord neurons of the ventral horn (efferent axons to muscles)
Basal nucleus of meynert

Question 20

Dopamine

Answer 20

Sustantia negra

Regulates motor function and limbic function…lactation

Question 21

NE

Answer 21

Locus cerulus…innervates thalamus, hypop, and limbic ofrebrain

Question 22

Serotonin

Answer 22

Raphe system
Rostral - diencephalon and telencephaolon
Caudal - spinal cord

Question 23

Neuropeptides

Answer 23

Enkephalins and substance P
Dorsal horn and afarent nuclei
Pain

Question 24

Structure of peripheral nerve

Answer 24

Endoneurium surrounds each axon
Perineurium wraps nerve fibers into fascicles
Epineurium surrounds entire nerve that contains blood vessels

Question 25

Neuroglial cells of CNS

Answer 25

Astrocytes - BBB
Microglia - phagocytosis
Epnndymal cells
Oligodendrocytes

Question 26

Astrocytes

Answer 26

Have feet that help form BBB…also the glia limitans

Question 27

Protoplasmic astrocytes

Answer 27

Gray matter

Make tight junctions with endothelial cells and create BBB

Question 28

Fibrous astrocytes

Answer 28

White matter
Contact axon at node of ranvier
Remove excess K+ in extra cellular space during impulse condcutiin

Question 29

Microglial cells

Answer 29

Immune cells
From embryonic yolk sac

If injured, can have activation and lead to dysfunctional state if chronic

Question 30

Ependyma

Answer 30

Ventricels of brain and central canal of spinal cord

Ependymal cells - cilia and microvilli and contact astrocytes…attached by belt desmosomes

Tanycytes - 3rd ventricle only…through the astorfcyte process and attached by tight junctions

Question 31

Nucleus

Answer 31

Assumulation of nerve cell bodies in gray matter

Question 32

Nerve vs. ganglion

Answer 32

Nerve- accumulation of ONLY cell processes (axons) with any type of CT and blood vessels

Ganglion - presence of a single cell body

Question 33

Schwann vs satellite cell

Answer 33

Schwann - only the processes

Satellite - only the cell body

Question 34

Appearance of CNS vs PNS

Answer 34

CNS - support cells randomly arranged

PNS - form a capsule

Question 35

Sensory ganglia of the pNS

Answer 35

Psuedounipolar neurones that have discrete organization because of thick bundles

Question 36

Sympathetic ganglia of the PNS

Answer 36

Multipolar neurons that are randomly distrubuted and a thinner CT capsule

Lie outside of the muscle wall

Question 37

Parasympathetic ganglia of the PNS

Answer 37

Have small numbers of multipolar nuerons…CT capsule very veyr thiner and in wall of organ

Auerbach’s plexus in between muscle of GI

Question 38

If lesion of axon

Answer 38

Chromatolysis where Nissls substance degenerate

Neurite club forms as neurons leave and try to come back

Eventually, if one makes contact with schwann cell, then will grow and others will die

Schwann and fibroblasts can scar

Both retrograde and anterograde degeneration