NERVOUS TISSUE (Lecture 7)

Question 1

main function of nervous tissue

Answer 1

COMMUNICATION

coordinates body function w/ the internal and external env.

Question 2

sensory input =

Answer 2

afferent = info brought from the periphery to the CNS

external stimuli: touch, pain, temp, muscle tension

Question 3

motor output =

Answer 3

efferent = info LEAVING the CNS to the periphery

ex: skeletal muscle - voluntary movement like locomotion, chewing, refle

Question 4

CNS is made up of the _____ and ______

Answer 4

Brain and Spinal cord

Question 5

The Peripheral NS is made of the _____ + ______

Answer 5

cranial nerves + spinal nerves

Question 6

Is there any connective tissue in the CNS?

Answer 6

NOOO

Question 7

the 2 fundamental cells in the nervous tissue

Answer 7

Neurons (functional)
Glial cells (support)

Question 8

what is included in Neuropil

Answer 8

synaptically dense regions composed of UNmyelinated axons, dendrites, and processes of glial cells

Question 9

primary function of neurons

Answer 9

generate & propogate action potentials

Question 10

functions of Dendrites

Answer 10

• receive info from other neurons
• have dendritic spines that increase the SA

dendrites have the same organelles as a cell body MINUS A NUCLEUS

Question 11

what is unique about dendrite membrane receptors

Answer 11

they can change the potential of the cell membrane

Question 12

what is contained within a Nissl body?

Answer 12

rough endoplasmic reticulum and free ribosomes

Question 13

what kind of DNA is found within a neuron cell body

Answer 13

Euchromatin

Question 14

contents of a neuron cell body

Answer 14

• nucleus
• nucleolus
• nissl bodies
• golgi complexes
• mitochondra
• neuro filaments
• microtubules

Question 15

what are neurofilaments?

Answer 15

intermediate filaments that provide structural support to the cell

considered a cytoskeletal structure

Question 16

function of the axons

Answer 16

transport impulses from the cell body

Question 17

function of dendrites

Answer 17

receive external impulses and tranport them towards cell body

Question 18

what does it mean that axonal transport is Bidirectional ?

Answer 18

synaptic vesicles can undergo anterograde or retrograde transport

Question 19

what is axonal transport

aka exoplasmic tranport

Answer 19

axonal transport is the movement mechanism of mitochondra, lipids, synaptic vesicles to & from the cell body and axon

Question 20

which type of axonal transport is fast

anterograde or retrograde

Answer 20

retrograde

transport TOWARD cell body when cell membranes are being returned to the cell body for reuse or degradation

Question 21

synapses are connections between ________ used for communcation

Answer 21

between NEURONS

Question 22

what initiates neurotransmitter release

Answer 22

action potential !

Question 23

the narrow gap that separates neurons

Answer 23

synaptic cleft

Question 24

synaptic vesicles contain ______?

Answer 24

Neurotransmitters

Question 25

what releases ACh from a motornueron and then propogates an action potential w/in the muscle fiber

Answer 25

the Neuromuscular synapse

Question 26

most common type of neuron

Answer 26

multipolar neuron

Question 27

where are pseudounipolar neurons found?

Answer 27

sensory ganglia | spinal nerve sensory ganglia and some cranial nerves

Question 28

what are ganglia?

Answer 28

clusters of cell bodies

Question 29

What are Glia cells?

Answer 29

Non-neuronal cells of the NS - interstitial, supportive cells for neurons within the NS | Astrocytes, migroglia, schwann cells (PNS), oligodendrocytes (CNS)

Question 30

what are the primary immune defense cells of the CNS

Answer 30

microglia | 10-15% of glia

Question 31

function of microglia?

Answer 31

- can become phagocytic and antigen-presenting - remove damaged neurons and infectious agents

Question 32

astrocytes have 'feet' that help them support what 2 things?

Answer 32

- BBB - Glia limitans (barrier b/w pia matter and CNS)

Question 33

where are Schwann cells found

Answer 33

PNS

Question 34

Where are oligodendrocytes found

Answer 34

CNS

Question 35

purpose of Schwann cells

Answer 35

- myelinate PNS axons | can only myelinate a single internodal segment per axon

Question 36

purpose of oligodendrocytes

Answer 36

compose the myelin of the CNS ## Footnote can myelinate more than one axon and more than one internodal segment per axon

Question 37

purpose of myelination

Answer 37

improves conductivity of axons, speeds things up | myelination electrically insulate axons to increase conduction

Question 38

where on an axon is myelin NOT found

Answer 38

initial segment and axon terminal

Question 39

name for regions where myelin is present | myelin present = insulated

Answer 39

internodal segments

Question 40

spaces b/w internodal segments | where axon is exposed

Answer 40

nodes of ranvier

Question 41

what is it called when an action potential 'jumps' from node to node

Answer 41

Salatory conduction

Question 42

myelin is a _____ rich structure

Answer 42

phospholipid

Question 43

what is the myelin sheath formed from

Answer 43

compressed layers of glial cell plasma membrane

Question 44

myelin sheaths

Question 45

________ envelops the myelin sheaths of individual axons of peripheral nerves

Answer 45

endoneurium - composed of reticular fibers - produced by schwann cells

Question 46

______ surrounds each bundle of nerve fibers (fascicle) of peripheral nerves

Answer 46

perineurium

Question 47

______ is a fibrous coating around an entire peripheral nerve, also fills the space b/w nerve fibers

Answer 47

Epineurium

Question 48

what are the 3 CT of peripheral nerves?

Answer 48

endoneurium, perineurium, epineurium

Question 49

explain why an 'unmyelinated axon' isn't truly without schwann cells

Answer 49

these axons are smaller in diameter so they have slower conduction BUT they are still enveloped by glial cells | **enveloped not Wrapped is main difference