M5S2 Histology Of The Neural Tissue

Question 1

What are the two principals of the nervous system

Answer 1

Neurons and supporting cells

Question 2

Explain neurons

Answer 2

-aka nerve cells
-excitable and can generate and transmit rapid electrical signals to other neurons

Question 3

Neuron structure

Answer 3

-neurons are structural units of the nervous system
-allow for communication within and between the CNS and PNS

All have similar structures:

Cell body
-aka soma
-houses nucleus and other organelles
-functions to transfer electrical signals from the dendrites to the axon

Cytoplasmic processes
1. Dendrites
-receives the neuronal signal from other neurons and transfer those signals to the cell body
2. Axon
-1 per neuron
-carry signal from the cell body to the axon terminals, where signal transferred to other neurons or organs

• refer to goodnotes for image

Question 4

Direction of nerve impulse

Answer 4

-neurons allow organs within the body to communicate with one another through rapid transduction of electrical signals known as nerve impulses
-nerve impulse = unidirectional
-signal travels from dendrites to cell body through he axon to reach dendrites of adjacent neurons or target organs
-SIGNALS DO NOT TRAVEL IN THE OPPOSITE DIRECTION

Question 5

Classifications of neurons

Answer 5

-based on number of cellular processes (dendrites and axon) that extend from the cell body

Pseudounipolar (unipolar)
Bipolar
Multipolar

*refer to goodnotes

Question 6

What does Gila mean and do

Answer 6

Gila mean s glue so neuroglia are like glue that holds it together

Question 7

Support cells summed up

Answer 7

-component of nervous system
-known as neurogila or Gila
-function to protect and support neurons and aid in sending signals between neurons to improve communication
-unlike neurons, cells do not generate or transmit nerve impulses

• refer to goodnotes for maybe unrelevant photo

Question 8

Supporting cells of the CNS

Answer 8

4 types

Astrocytes
-large star shaped cells with numerous processes
-communicate with neurons and blood vessels to maintain integrity of the neural tissue
-most abundant of the glial cells in CNS

Microglia
-aka small glial cells
-perform many protective functions in CNS
-able to phagocytose or engulf and destroy pathogens and eliminate waste products from other cells
-least common type of supporting cells

Ependymal
-cuboidal
-line cavities of brain and spinal cord
-assist in production, circulation, and monitoring of cerebrospinal fluid (CSF)

Oligodendrocytes
-wrap around axon in CNS to form myelin sheath
-single cell can myelinate up to 60 axons
-many processes that extend to myelinate axons

• refer to goodnotes for image

Question 9

Describe what many diseases like sclerosis leads to

Answer 9

Demyelination of axons, which leads to neurological symptoms

Question 10

Myelination

Answer 10

-one important function of some neurogila is to myelinate ( wrap myelin around) part of an axon
-myelin is composed of mainly fat and appears white
-insulates the axon and increases the speed which electrical signals can travel down the axon

-some small regions of axon are unmyelinated between adjacent regions of myelination
-these unmyelinated regions are known as nodes of ranvier (neurofibril nodes).

Question 11

Schwann cell

Answer 11

-main type of neurological cell in PNS
-equivalent to oligodendrocytes in that they form the myelin sheath around nerve fibres (axon) in PNS
-a single Schwann cell can only myelinate a portion of one axon, as they do not have processes like oligodendrocytes

• refer to goodnotes image