W1: Fundamentals of Nervous Tissue

Question 1

Central Nervous System (CNS)

Answer 1

The command center consisting of the brain and spinal cord. It receives sensory signals, interprets them, and dictates motor responses.

Question 2

Peripheral Nervous System (PNS)

Answer 2

Nervous system outside of the CNS. Consists of nerves extending outside of the brain and spinal column.

Question 3

Afferent Neurons

Answer 3

Have axons that carry information toward the CNS.

Question 4

Efferent Neurons

Answer 4

Have axons that carry information away from the CNS.

Question 5

Interneurons

Answer 5

Neurons that connect to other neurons within the same general area (i.e. spinal cord)

Question 6

Somatic Motor Neurons

Answer 6

(Voluntary) innervation to skeletal muscle.

Question 7

Somatic Sensory Neurons

Answer 7

CNS > Skeletal muscles. Touch, pain, pressure, vibration, temperature, proprioception from skin, body wall, and limbs. Special: Hearing, equilibrium, hearing.

Question 8

Visceral Motor Neurons

Answer 8

(Involuntary - ANS) Innervation to smooth & cardiac muscle and glands.

Question 9

Visceral Sensory Neurons

Answer 9

CNS > Smooth, cardiac muscles and glands. Stretch, pain, temperature, chemical changes, irritation of viscera, nausea and hunger. Special: Taste and smell.

Question 10

General Characteristics of a Neuron:

Answer 10

1. excitable cells
2. do NOT divide after birth, but some neurogenesis from adult stem cells.
3. Normally live a long life
4. High metabolic rate - require large amounts of glucose and oxygen.
5. Have 2 types of processes (dendrites/receivers & axons/senders)

Question 11

Proprioception

Answer 11

Sensing one’s own body.

Question 12

What structures make up the soma/cell body?

Answer 12

1. Plasma membrane
2. Nucleus/nucleolus
3. Nissl bodies/rough ER
4. Golgi Apparatus
5. Neurofilaments

Question 13

Dendrites

Answer 13

Intermediate filaments that provide structural integrity. They receive synapic contact from other neurons. Types: Multipolar & bipolar.

Question 14

Dendritic Spines

Answer 14

Enlarge the surface area of the plasma membrane

Question 15

Axon

Answer 15

Cell signaling between neurons.

Question 16

Axon Hillock

Answer 16

Where the axon tappers from the cell body; site where action potentials are generated. (Decision Maker)

Question 17

Axonal Neurotubules

Answer 17

Parallel arrays of processes that help axon retain shape.

Question 18

Axon Collateral

Answer 18

Sideways branches off of an axon.

Question 19

Axonal Transport

Answer 19

1. Anterograde

2. Retrograde

Question 20

Anterograde Axonal Transport

Answer 20

Tracer: Phaseolus vulgaris (Phal), Biotinylated DextranAmine (BDA), Triated Amino Acids (H^3 amino acids)
Injection of tracer into CNS and taken up by cell bodies then transported down the axon. Tracer accumulates in axon terminals labeling terminal boutons. Tells you which regions of the CNS receive neuron projections.

Question 21

Retrograde Axonal Transport

Answer 21

Tracer: Horseradish Peroxidase (HRP)
Injection of tracer into the CNS and taken up by terminals and transported back to the cell body. This labels which cell bodies that project to the area of of your injection site.

Question 22

Types of Synapses:

Answer 22

1. Axosomatic synapses
2. Axoaxonic synapses (axon-axon)
3. Axodendritic synapses

Question 23

Where do synapses occur?

Answer 23

Between an axon terminal and a postsynaptic structure.

Question 24

What are the primary structures of an axon terminal?

Answer 24

1. Presynaptic terminal
2. Synaptic Cleft
3. Postsynaptic terminal

Question 25

Information flow in neurons...

Answer 25

is ALWAYS in one direction.

Question 26

Excitatory Neurotransmitter causes:

Answer 26

target neuron to depolarize and fire.

Question 27

Inhibitory Neurotransmitter causes:

Answer 27

target neuron to hyperpolarize and NOT fire.

Question 28

What postsynaptic elements can axon terminals form synapses with?

Answer 28

1. axosomatic 2. axodendritic/axospinous 3. axoaxonic

Question 29

How do you identify the different types of synapses?

Answer 29

Electronmicroscope

Question 30

What is the neurotranmitter for any neuromuscular junction?

Answer 30

acetylcholine

Question 31

Characteristics of glial/supporting cells and how they differ from neurons:

Answer 31

1. Can divide throughout life 2. Have only one type of process (rather than two) 3. Each type of glia has specific functions that support neurons. 4. Smaller in size and have darker staining nuclei. 5. Different kinds of glia in CNS and PNS.

Question 32

Types of Glial/Supporting cells in the CNS:

Answer 32

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

Question 33

Astrocyte

Answer 33

"Star" - Glia - Cause tumors in the brain - They control the environment surrounding the neuron by metabolizing and recylcing neurotransmitters. - Release growth factors - Promote neural survival

Question 34

Oligodendroglia

Answer 34

"Few" - Myelin generating glia - Degradation causes MS - They line axons and wrap think axons to form myelin in CNS - Speed up action potentials (insulators) - Can degrade over lifetime - Can wrap many axons at once

Question 35

Microglia

Answer 35

"Small" - Glia - Immune system cell in CNS - Act as phagocytes by removing debris - hard to find in healthy brains but divide and multiply quickly in sick brains

Question 36

Ependymal Cell

Answer 36

- NOT glia - Found in only one place = lining of neural tube - Divide CNS and fluid of ventricular tissue

Question 37

Supporting cells of the PNS

Answer 37

1. Schwann Cells 2. Nodes of Ravier 3. Myelin from Schwann cells

Question 38

Schwann Cell

Answer 38

- Myelin generating glia - increase speed of action potentials - surround large axons 6-10 times with lipoprotein

Question 39

Node of Ranvier

Answer 39

- Space of exposed axon between myelin | - current jumps between nodes to increase action potential speed

Question 40

Features of a nerve:

Answer 40

1. Axons 2. Myelin Sheaths 3. Fascicle 4. Blood vessels

Question 41

What types of nerves are considered peripheral nerves?

Answer 41

1. Collection of axons traveling together 2. Motor, sensory, and mixed nerves 3. Nerve fascicles covered in layers of connective tissue

Question 42

Golgi Stain

Answer 42

- Inconsistent - Best way to show full neuron - Works well to study neurons in development but not on myelinated cells - Soak in potassium dichromate then silver nitrate - Good for comparative, classification, and developmental studies

Question 43

Nissl Stain

Answer 43

-Basic stain that differentiates gray matter easily -High pH stain; attracted to nucleic acids of nucleus and rough ER. -

Question 44

Immunocytochemistry

Answer 44

Anatomical technique used to characterize the presence of chemicals in cells. -The rate limiting synthesizing enzyme indicates the appropriate neurotransmitter made by a cell.

Question 45

ChAT

Answer 45

Choline acetyltransferase | =the sunthesizing enzyme

Question 46

Acetylcholine

Answer 46

major excitatory neurotransmitter at both CNS synapses and neuromuscular junctions.

Question 47

Acetyl Cholinesterase

Answer 47

enzyme that degrades the neurotransmitter in the synaptic cleft.