1.1 neuro - neurohistology

Question 1

How are neurons classified?

Answer 1

By their structure and function, including types such as pseudo-unipolar, bipolar, and multipolar.

Question 2

What are the important characteristics of neurons?

Answer 2

Excitable (generate and propogate action potentials), postmitotic (do not divide), and highly variable.

Question 3

What are the parts of a neuron that should be sketched and labeled?

Answer 3

Cell body (soma), nucleus, dendrites, axon, myeline sheath

Question 4

What is the function of an axon?

Answer 4

To send information and carry nerve impulses to other neurons, muscle fibers, or glands.

Question 5

What is the function of a dendrite?

Answer 5

Cellular extensions that receive information.

Question 6

What are the 3 types of neurons in vertebrates?

Answer 6

• Pseudo-unipolar (1 process exits the soma and splits into a central -to CNS- and peripheral -to environment- process)
• Bipolar (1 axon and 1 dendrite)
• Multipolar (1 axon, many dendrites)

Question 7

What are the components of a synapse?

Answer 7

• Presynaptic neuron
• Synaptic vesicles
• Presynaptic membrane
• Neurotransmitters
• Synaptic cleft
• Postsynaptic membrane
• Receptors
• Postsynaptic neuron

Question 8

What is the primary function of neuroglia?

Answer 8

Support, nourish, and protect neurons. Form the blood-brain barrier

Question 9

What is the difference between neurons and neuroglia?

Answer 9

Neurons are excitable and postmitotic, while neuroglia outnumber neurons, do not propagate impulses, and can divide.

Question 10

What are the types of glia found in the central nervous system?

Answer 10

• Astrocytes
• Oligodendrocytes
• Microglia
• Ependymal cells

Question 11

What are the types of glia found in the peripheral nervous system?

Answer 11

• Schwann cells
• Satellite cells

Question 12

What cells are responsible for myelination in the CNS?

Answer 12

Oligodendrocytes.

Question 13

What cells are responsible for myelination in the PNS?

Answer 13

Schwann cells.

Question 14

Which cell type lines the ventricles?

Answer 14

Ependymal cells.

Question 15

Which cells migrate into the CNS and are not derived from the neural crest or neural tube?

Answer 15

Microglia.

Question 16

What cell types form the blood-brain barrier?

Answer 16

• Astrocytes
• Endothelial cells of capillaries

Question 17

What is the main component of gray matter?

Answer 17

Neurons and their proximal dendrites.

Question 18

What is the main component of white matter?

Answer 18

Myelinated axons.

Question 19

What is the function of astrocytes?

Answer 19

To maintain the blood-brain barrier and support neuronal function.

Question 20

True or False: Microglia originate from the neural tube.

Answer 20

False.

Question 21

Fill in the blank: The _______ consists of tight junctions between the endothelial cells of brain capillaries and the foot processes of astrocytes

Answer 21

Blood-Brain Barrier

Question 22

What are Nissl bodies responsible for?

Answer 22

High levels of protein synthesis.

Question 23

What is the role of ependymal cells?

Answer 23

• Line the ventricles of the brain and central canal of the spinal cord
• Form the choroid plexus
• Form the cerebrospinal fluid barrier

Question 24

How do oligodendrocytes contribute to white matter?

Answer 24

By myelinating multiple axons.

Question 25

What substances cross the blood-brain barrier freely?

Answer 25

Lipid-soluble substances - Oxygen - Carbon dioxide - Alcohol - Most anesthetic agents

Question 26

What substances cross the blood-brain barrier very slowly?

Answer 26

Water-soluble substances - glucose - creatine - urea - most ions

Question 27

What is the difference between myelinated and unmyelinated axons?

Answer 27

Myelinated axons are covered by a myelin sheath (multilayered lipid and protein covering), while unmyelinated axons are not.

Question 28

What two types of cells comprise nervous tissue?

Answer 28

Neurons and neuroglia

Question 29

What is the purpose of the cell body of a neuron?

Answer 29

Contains nucleus and other organelles

Question 30

What are nissl bodies

Answer 30

Large stacks of rough endoplasmic reticulum in neurons

Question 31

What do axon terminals do?

Answer 31

Participate in synapses of neurons

Question 32

What is a synpase?

Answer 32

Site of communication between two neurons

Question 33

Presynaptic neuron

Answer 33

Neuron carrying an impulse toward a synapse (axon)

Question 34

Postsynaptic neuron

Answer 34

Neuron carrying an impulse away from the synapse (dendrite)

Question 35

What is a synapse between a neuron and a muscle fiber?

Answer 35

Neuromuscular junction

Question 36

Presynaptic membrane

Answer 36

Site of neurotransmitter release

Question 37

Synaptic cleft

Answer 37

Small space between teh pre and post synaptic sites, contains enzymes that break down neurotransmitters

Question 38

Postsynaptic membrane

Answer 38

Site of neurotransmitter reception

Question 39

Where are neurotransmitters located in synapses

Answer 39

In synaptic vesicles in the presynaptic neuron

Question 40

Do glia generate or propogate impulses? Do glia divide?

Answer 40

No; Yes

Question 41

What is the function of the blood-brain barrier

Answer 41

Protect brain cells from harmful substances and pathogens

Question 42

What types of substances can not cross the BBB?

Answer 42

Proteins and most antibiotic drugs

Question 43

What cells surround the bodies of neurons of PNS ganglia?

Answer 43

Satellite cells

Question 44

Function of microglia?

Answer 44

Resident macrophages; Remove cellular debris, microbes, and damaged nervous tissue

Question 45

What do schwann cells do?

Answer 45

Myelinate cells of the PNS

Question 46

What do satellite cells do?

Answer 46

Surround the bodies of neurons of PNS ganglia