Cells In Brain

Question 0

Typical neurone

Answer 0

Several main parts: soma, axon and dendrites

Inside of neurone separated from outside by neuronal membrane

Question 1

Two main types of cell in ns

Answer 1

Neurones- sense changes in environment, convey info to other parts of rain
Glia - insulates supports and nourishes neurones

Question 2

Soma (cell body)

Answer 2

Watery fluid inside cell is cytosol
Cytoplasm is everything in cell membrane except from nucleus
Nucleus inside nuclear envelope. Containss DNA
Mitochondria, golgi apparatus, smooth ER

Question 3

Cytoskeleton

Answer 3

Scaffolding of neurone
Gives it the shape
Microtubules, microfilaments and neurofilaments

Question 4

The axon

Answer 4

Begins at axon hillock
No rough ER and few ribosomes
Protein comp is different than soma
Middle of axon is axon proper. End is axon terminal

Question 5

How can neurones be classified

Answer 5

By total no of dendrites, axons, axon length, connections and tpe of neurotransmitter they use

Question 6

Classification: no of axons

Answer 6

Unipolar (one axon, soma is a projection) sensory from skin
Bipolar (2 axons, soma lies in the middle) olfactory, retina
Multipolar (most in the brain are multipolar)

Question 7

Classification: dendrites

Answer 7

Shape: stellate cells (star shaped), pyramid cells, double bouqet, basket cells
Presence of spines: spiny or aspinous

All pyramid cells are spinous. Stellate can be either

Question 8

Classification: axon length

Answer 8

Golgi type 1- projections that extend from one part of brain to other

Golgi type 2- dont extend beyond vicinity of cell body. Local circuitry

Question 9

Classification: connections

Answer 9

Primary sensory
Motor
Interneurones

Question 10

Glia

Answer 10

Support neuronal functions
Astrocytes
Myelinating glia
Ependymal cells
Microglia

Question 11

Astrocytes

Answer 11

Most numerous glia
Fill space between neurones. Decides whether neurone grows or retracts
Regulates chemical content of extracellular space. K+
Envelopes synapse preventing spread of neurotransmitter
Membrane has NT receptors that can trigger electrical events in astrocyte

Question 12

Myelinating glia

Answer 12

Oligodendrocytes (CNS) and schwann cells (PNS)
Provides layers of membrane that insulate axons (myelin)
Sheath interrupted at nodes of ranvier
One oligodendrocyte myelinates many axons, one schwann cell only myelinates one axon

Question 13

Ependymal cells

Answer 13

Lining of fluid filled ventricles

Play role in directing cell migration during brain development

Question 14

Microglia

Answer 14

Function as phagocytes to remove debris from dead or degenerating neurones and glia