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Flashcards in Lecture 6 - Nerves Deck (56):
1

2 Divisions of the Nervous System

1. Central
2. Peripheral

2

Components of CNS

Brain and Spinal Cord

3

Components of PNS

Cranial, spinal, peripheral nerves and ganglia

4

What are the 2 types of cells in the CNS and PNS?

1. Neurons
2. Glial Cells

5

Features of a Multipolar Neuron (x6)

1. Dendrites (2 or more)
2. Cell Body
3. Axon (one) - goes off into periphery
4. Located in spinal cord
5. Motor Neurons and CNS interneurons
6. Most Neurons

6

Features of Bipolar Neuron (x4)

1. Dendrite (1)
2. Cell Body
3. Axon (1)
4. Sensory neurons of the retina, olfactory mucosa, and inner ear

7

Features of Unipolar Neurons

1. Dendrites
2. Axon - Peripheral Process, Central Process
3. Cell Body w/ Single short process

8

What are the types of neurons based on their functional role?

1. Motor (efferent)
2. Sensory (afferent)
3. Interneuron (more than all other neurons combined)

9

Nissl Bodies

1. Ribosomes
2. RER

10

Are Nissl bodies acidophilic of basophilic?

Basophilic --> lots of ribosomes (acid)

11

Why does the peikaryon have a euchromatic nucleus, very prominent nucleolus, and Nissl bodies?

Making lots of proteins

12

What is the Axon Hillock?

The thicker extension of the axon closest to the cell body

13

What maintains the structure of the neuron?

Neurofilaments (aka intermediate filaments) and neurotubules (aka microtubules)

14

What are the functions of the cytoskeleton in a neuron? (x2)

1. Mechanical Support
2. Intracellular Trafficking

15

Where are neurotransmitters made? Where do they go? How do they get there?

1. NT's are made in the cell body
2. They are stored in synaptic vesicles at the terminal end of the axon.
3. They get there by traveling down the axon using the cytoskeleton (neurofilaments and neurotubules)

16

Is transport in the axon unidirectional or bidirectional?

Bidirectional

17

What are the names for the modes of transportation up and down an axon?

1. Anterograde Transport
2. Retrograde Transport

18

What is the plasma membrane of the axon called?

Axolemma

19

What is the cytoplasm of the axon called?

Axoplasm

20

What does the axoplasm contain?

1. Mitochondria
2. Microtubues
3. Neurofilaments
*Think MMR*
*No protein synth is made here - no ribosomes/rER

21

What are dendrites?

Elongated processes specialized to receive stimuli from other neurons at contact sites known as synapses
*Dendritic Tree

22

Which is longer, dendrite or axon?

Axon

23

Which process will be more numerous, dendrite or axon?

Dendrite

24

What is the dendritic spine?

The site of synaptic contact w/ other neurons

25

What is the purpose of dendrites and the dendritic spines?

Increase surface are to receive as much stim as possible

26

What happens when a neuron receives an impulse?

1. An electrical impulse travels from the dendrite spine to the dendrite
2. Then to the cell body
3. Down the Axon
4. NT is released

27

What does the NT do after it is released?

1. Travels across the synaptic cleft
2. Binds to a receptor on the post synaptic membrane
3. Causes an effect

28

How to best see axons and dendrites on a microscopic image?

Gold Stain
*can also use basophilic stains like hematoxylin*

29

What is in the space between neuronal cell bodies?

1. Glial Cells
2. Glial and Neuronal Process (axons/dendites)

30

What are the major types of glial cells in the CNS?

1. Oligodendrocytes
2. Astrocytes
3. Ependymal Cells
4. Microglia

31

What are the major types of glial cells in the PNS?

1. Schwann Cells
2. Satellite Cells
*oligodendrocytes and schwann cells have similar functions

32

Purpose of oligodendrocytes?

Form the myelin sheath in the CNS

33

Purpose of schwann cells?

Form the myelin sheath in the PNS

34

How can impulses down the axons travel faster?

Myelin sheath insulates parts of the axon and makes the impulse "jump" from node to node (of ranvier)

35

What is the primary component of myelin?

Lipid

36

What glial cell myelinates parts of several axons in the CNS?

Oligodendrocyte

37

Where are schwann cells located and how are they different from oligodendrocytes?

1. In the PNS
2. Multiple schwann cells wrap themselves around a single axon, where as oligodendrocytes can myelinate several axons at the same tie

38

Compare the location of white matter to grey matter in the cranium

1. White matter is located more centrally
2. Grey matter is located near the cortex

39

What is the main component of grey matter?

1. Neuronal cell bodies

40

Compare the location of white matter to grey matter in the spinal cord

1. White matter is located around the outside of the spinal cord
2. Grey matter makes up the middle of the spinal cord

41

What is the most abundant glial cell in the CNS?

Astrocyte

42

Features of astrocytes

1. Very little cytoplasm
2. Elongated or oval nuclei
3. Numerous cytoplasic processes (star shaped = astro)
4. Part of the BBB

43

Main functions of astrocytes?

1. Regulate extracellular ion concentration
2. Metabolic support for neurons
3. Modulate Synaptic transmission
4. Nervous system repair
*"Helps Mets Modulate Nerves"*

44

What are the perivascular feet and what are their function?

1. Processes of the astrocyte that attach to blood supply
2. Helps maintain the BBB
3. Helps regulate local CNS blood flow

45

What cells line the Ventricles and Central Canal?

Ependymal Cells

46

What are ependymal cells?

Supporting cells
*similar to epithelial cells

47

Features of ependymal cells

1. Ciliated - move fluid through the NS
2. Have branches that go to parynchyma of the spinal cord
3. Capable of division and migration into neuropil to form new neurons

48

How to tell ependymal cells apart from epithelial cells?

Ependymal cells do not have a basal lamina or basment membrane to anchor to

49

Functions of the microglia

1. Protective
2. Phagocytic
3. Immune-related
4. Clear away dying cells and help repair neuronal damage
*evenly distributed in grey and white matter*

50

What are "nerves" composed of?

Axons

51

Where are ethe cell bodies of the axons w/in a peripheral nerve located?

CNS
*ganglia are in the PNS

52

Features of the Dorsal Root Ganglion

1. Contains Sensory (afferent) neurons
2. Have neuronal cell bodies - unipolar neurons

53

Features of satelite cells

1. Restricted to ganglia
2. Cover and support large neuronal cell bodies
3. Located in PNS

54

What is in a peripheral nerve?

1. Myelinated Axon
2. Unmyelinated Axon
3. Schwann Cell
4. Connective tissue

55

What layer covers the entire nerve?

Epineurium

56

Why are nerve fibers wavy?

When you stretch, there is no damaging tension on the nerve