Neurohistology

Question 2

What is the function of ependymal cells?

Answer 2

Ependymal cells have cilia which beat and appear to move cerebrospinal fluid (CSF)

Ependymal cells are found along the ventricular walls.

Question 3

What do modified ependymal cells do?

Answer 3

Modified ependymal cells (choroidal epithelial cells) filter blood from capillaries in the choroid plexus to produce cerebrospinal fluid (CSF)

Choroid plexus is a structure in the brain that produces CSF.

Question 4

What is the role of astrocytes?

Answer 4

Astrocytes regulate extracellular milieu, take up excess potassium, and take up excess neurotransmitter

CNTF induces astrocyte differentiation and GFAP is a commonly used marker for astrocytes.

Question 5

Where are protoplasmic astrocytes primarily found?

Answer 5

Protoplasmic astrocytes are found primarily in gray matter

Fibrous astrocytes are found primarily in white matter.

Question 6

What are microglia derived from?

Answer 6

Microglia are mesodermally derived and invade the CNS during development

They are involved in phagocytosis in the CNS.

Question 7

What is Nissl substance?

Answer 7

Nissl substance is rough endoplasmic reticulum (ER) in neurons

Cresyl violet and thionin are histochemical dyes that bind to Nissl substance.

Question 8

What are dendrites specialized for?

Answer 8

Dendrites are specialized for receiving information from other neurons

Dendritic spines increase the amount of surface area for additional synapses.

Question 9

What is the primary role of axons?

Answer 9

Axons transmit information to other neurons

Axons can be quite long and may be myelinated by Schwann cells (PNS) or oligodendrocytes (CNS).

Question 10

What are the types of synapses?

Answer 10

Types of synapses include:
* Axodendritic
* Axosomatic
* Axoaxonic
* Dendrodendritic

Axodendritic is the most common type of synapse.

Question 11

What are noradrenergic neurons characterized by?

Answer 11

Noradrenergic neurons are characterized by containing noradrenalin

Other types include dopaminergic (dopamine), serotinergic (serotonin), cholinergic (acetylcholine), GABAergic (GABA), and glutaminergic (glutamine).

Question 12

What is the purpose of gap junctions?

Answer 12

Gap junctions allow ions to flow freely between neurons, helping synchronize neuronal output

Connexin proteins found on two different neurons interact to form channels.

Question 13

What are the two forms of axonal transport?

Answer 13

The two forms of axonal transport are:
* Anterograde transport (to axon terminal)
* Retrograde transport (to cell body)

Microtubules are involved in transporting synaptic vesicles and signaling molecules.

Question 14

What histological changes are associated with Alzheimer’s disease?

Answer 14

Alzheimer’s disease is associated with:
* Plaques of beta-amyloid outside neurons
* Tangles of tau protein inside neurons

The roles of tangles and plaques in causing Alzheimer’s disease is hotly debated.

Question 15

What is chromatolysis?

Answer 15

Chromatolysis is a process that occurs in neurons during degeneration

Specific details about chromatolysis were not included in the provided text.

Question 16

What is a typical size range for neurons?

Answer 16

Neurons typically range in size from 4 to 135 µm

Neurons can be classified based on their size, shape, and location.

Question 17

What distinguishes projection neurons from interneurons?

Answer 17

Projection neurons have long axons that extend beyond their cell group, while interneurons have short axons that transmit information within the same cell group

Most neurons are multipolar, which can come in a wide variety of shapes.

Question 18

Fill in the blank: The _______ is the space between the presynaptic and postsynaptic membranes.

Answer 18

synaptic cleft

This space is crucial for neurotransmission.

Question 19

True or False: Dendrodendritic synapses are the most common type of synapse.

Answer 19

False

Axodendritic synapses are the most common type.

Question 20

What are the two main types of neurons based on axon length?

Answer 20

Projection neurons (long axons) and interneurons (short axons)

Question 21

What are projection neurons?

Answer 21

Neurons with long axons that project to distant areas of the brain or body

Question 22

What are interneurons?

Answer 22

Neurons with short axons, involved in local processing within regions

Question 23

What type of neuron is involved in motor control crossing over in the brainstem?

Answer 23

The pyramidal neuron that controls motor function and crosses in the brainstem

Question 24

What is a neurosecretory neuron?

Answer 24

A neuron that releases hormones into the blood

Question 25

Where are neurosecretory neurons located?

Answer 25

In the hypothalamus

Question 26

What do neurosecretory neurons release in the posterior pituitary?

Answer 26

Oxytocin and vasopressin

Question 27

What happens when Purkinje cells in the cerebellum are damaged?

Answer 27

Motor deficits and lack of coordination

Question 28

What are bipolar neurons?

Answer 28

Neurons with two processes, found in the retina and vestibular ganglia

Question 29

Where are pseudo unipolar neurons located?

Answer 29

In the dorsal root ganglia and cranial nerve ganglia

Question 30

What is the primary function of dendrites?

Answer 30

Receiving input from other neurons

Question 31

What is the primary function of axons?

Answer 31

Transmitting electrical signals over long distances

Question 32

What is the initial segment of a neuron responsible for?

Answer 32

Deciding whether the neuron fires or not, based on incoming signals

Question 33

What is myelin and which cells make it in the CNS and PNS?

Answer 33

A fatty substance that insulates axons; oligodendrocytes (CNS), Schwann cells (PNS)

Question 34

What is the role of Schwann cells?

Answer 34

Produce myelin in the peripheral nervous system (PNS)

Question 35

What is the role of oligodendrocytes?

Answer 35

Produce myelin in the central nervous system (CNS)

Question 36

What neurotransmitters are released at the neuromuscular junction?

Answer 36

Acetylcholine

Question 37

What is the significance of dendritic spines?

Answer 37

Increase the surface area for receiving synapses

Question 38

What is the Nissl substance in neurons?

Answer 38

Rough endoplasmic reticulum in neurons, involved in protein synthesis

Question 39

What are the major characteristics of Alzheimer's disease?

Answer 39

Amyloid plaques and neurofibrillary tangles

Question 40

What is the role of astrocytes in the CNS?

Answer 40

Regulate the extracellular environment, taking up excess potassium and neurotransmitters

Question 41

What do microglia do?

Answer 41

Phagocytose debris and dead cells in the CNS

Question 42

What is anterograde transport?

Answer 42

Transport from the cell body to the axon terminal

Question 43

What is retrograde transport?

Answer 43

Transport from the axon terminal to the cell body

Question 44

What is the difference between protoplasmic and fibrous astrocytes?

Answer 44

Protoplasmic astrocytes are found in gray matter, while fibrous astrocytes are found in white matter

Question 45

What neurotransmitter do cholinergic neurons release?

Answer 45

Acetylcholine

Question 46

What are the two major types of synapses?

Answer 46

Chemical synapses and electrical synapses

Question 47

What is an axo-dendritic synapse?

Answer 47

A synapse where an axon connects to a dendrite

Question 48

What is an axo-somatic synapse?

Answer 48

A synapse where an axon connects to a cell body

Question 49

What is an axo-axonic synapse?

Answer 49

A synapse where an axon connects to another axon

Question 50

What are gap junctions?

Answer 50

Channels that allow direct electrical communication between neurons

Question 51

What is the synaptic cleft?

Answer 51

The gap between neurons where neurotransmitters are released

Question 52

What is saltatory conduction?

Answer 52

The jumping of action potentials between nodes of Ranvier to speed up signal transmission

Question 53

What is the role of the axon terminal?

Answer 53

Releasing neurotransmitters into the synaptic cleft

Question 54

What is the purpose of Kinesin and Dynein proteins?

Answer 54

Transport proteins that move vesicles along axons

Question 55

Where is cerebrospinal fluid (CSF) produced?

Answer 55

In the choroid plexus

Question 56

What are neurofibrillary tangles associated with?

Answer 56

Aggregates of tau protein within neurons, characteristic of Alzheimer's

Question 57

What is a pseudounipolar neuron?

Answer 57

A neuron with a single process that splits into two branches

Question 58

What is the difference between sensory and motor neurons?

Answer 58

Sensory neurons transmit signals from sensory receptors; motor neurons control muscle movement

Question 59

Where do you find lower motor neurons in the body?

Answer 59

In the spinal cord and brainstem

Question 60

What is the function of the dorsal root ganglion?

Answer 60

Contains the cell bodies of sensory neurons in the peripheral nervous system

Question 61

What happens in chemical synapses?

Answer 61

Neurotransmitters are released into the synaptic cleft and bind to postsynaptic receptors

Question 62

What role do microglia play in the CNS?

Answer 62

Immune cells of the CNS that clear dead cells and fight infection

Question 63

How do astrocytes regulate the extracellular environment?

Answer 63

They help reset the environment after synaptic activity by taking up excess ions and neurotransmitters

Question 64

What are vesicles in a neuron responsible for?

Answer 64

Store neurotransmitters and release them at the axon terminal

Question 65

What do satellite cells do?

Answer 65

Insulate pseudounipolar neurons in the dorsal root ganglia

Question 66

What is the blood-brain barrier?

Answer 66

A barrier that protects the brain from harmful substances in the blood

Question 67

What are electrical synapses?

Answer 67

Rare synapses that allow electrical signals to pass directly between neurons

Question 68

How do plaques and tangles affect neurons in Alzheimer's disease?

Answer 68

They disrupt normal cell function by interfering with cellular processes and causing cell death