T1L4:Neural Tissues

Question 1

what are the differences between the PNS and CNS

Answer 1

CNS:
-Brain and spinal cord

• Information processing
• including reflexes and behaviour

PNS:

• Sensory detection
• motor detection

Question 2

which embryonic layer does the NS come from

Answer 2

-the ectoderm

Question 3

what is the difference between an afferent and efferent neuron

Answer 3

• afferent: : transmit
  sensory information to
  brain/spinal cord

efferent :: motor neurons transmitting information from brain to effector organ i.e. muscle

Question 4

what is a ganglion

Answer 4

group of cell bodies outside the CNS

Question 5

give examples of ganglions

Answer 5

• dorsal root ganglion

- sensory ganglion

Question 6

describe the motor ganglion

Answer 6

autonomic

Question 7

describe the parasympathetic ganglion

Answer 7

• smaller neurons

- eccentric nuclei

Question 8

what is the equivalent of ganglia in the brain

Answer 8

• Nuclei/nucleus: In CNS groups of neurons called “nucleus”

Question 9

go over slide 10:

Directions in human prefrontal cortex

Answer 9

• how was it

Question 10

what is the significance of Brodmann areas

Answer 10

Each Brodmann area has a particular set of inputs and outputs.

Often a Brodmann area will have a function

Question 11

what is Brodmann area 4 and 17

Answer 11

4: ~primary motor cortex
17: primary visual cortex

Question 12

what is the CNS neuron

Answer 12

: nucleus within cell body and

extends one or more processes

Question 13

what is a process of a neuron

Answer 13

-is the generic term for any outgrowth from the cell body of a neuron (e.g. a dendrite is a process, and also an axon is a process).

Question 14

go over slide 12:labelling of a neuron

Answer 14

how was it

Question 15

describe the function of the myelin sheath

Answer 15

Electrically Insulates.

increasing conduction velocity

Question 16

structure of myelin sheath

Answer 16

Made of many layers of cell membrane

Question 17

what are the different neural classifications

Answer 17

multipolar, bipolar and unipolar

Question 18

what are the important neurons

Answer 18

1- pyramidal cell-neocortex

2- purkinje cells-cerebellum

3- Dorsal root ganglion-sensory neuron

Question 19

difference between a bipolar neuron and a pseudo-unipolar neuron and give e.g. of each

Answer 19

Bipolar:

• 1 dendrite
• 1 axon
• least numerous
• sensory neurons
• e.g.- retina

pseudo-unipolar:

• 1 axon
• 1 dendrite
• e.g. dorsal root ganglion

Question 20

what is a chemical synapse

Answer 20

-Synapse = A functional link

-Post-synaptic cell =
neuron,
myocyte, or
gland

chemical synapse :
Big gap = ~ 30 nm
Common throughout nervous system
Signalling is NOT in retrograde direction*E
*E There are some exceptions
Presynaptic cell releases neurotransmitter

Postsynaptic cell receptor —> electric signal

Question 21

what is the difference between convergent and divergent

Answer 21

-Divergent- A single neuron sends its output signal to many neurons
E.g. Skin

convergent:multiple inputs influence a single neuron
E.g. Retina

Question 22

describe interneurons

Answer 22

Interneurons occur only in CNS.
They are neither motor nor sensory.
They process signals

Question 23

how do neurons differ from glia

Answer 23

-glia:

• have no AP
• Are able to divide
• don’t form synapses
• form myelin sheaths

Question 24

what are the roles of glial cells

Answer 24

• supportive

- protective

Question 25

-go over slide 24 for the different types of glial cells

Answer 25

-how was it

Question 26

describe oligodendrocytes

Answer 26

- production / maintenance of myelin sheath in CNS -1 oligodendrocyte myelinates multiple axons (from different neurons)

Question 27

describe astrocyte function

Answer 27

1- Its “feet” on processes abut blood vessel endothelium – influence BLOOD FLOW and BLOOD-BRAIN BARRIER 2-supports neurons: assists neuronal development / growth (neurotrophic), 3- protects neurons from harmful substances

Question 28

describe the microglia

Answer 28

-immune cells, protect neurons from disease, migrate to injury sites, engulf microbes / debris, mesodermal origin

Question 29

describe ependymal cells

Answer 29

-line brain’s ventricles and central canal of spinal cord, form CSF -made up of cilia + microvilli on apical membrane

Question 30

describe schwann cells (PNS)

Answer 30

-production / maintenance of myelin sheath, PNS regeneration -1 axon wrapped per Schwann cell,Compare to oligodendrocytes (in CNS)

Question 31

describe satellite cells

Answer 31

- support neurons, regulate exchange of materials between neurons and interstitial fluid - Perform analogous role in PNS to what astrocytes do in CNS

Question 32

how do you classify glia

Answer 32

Central Nervous System: - Astrocyte - Oligodendrocyte - Ependymal cell - Microglial cell Peripheral Nervous System: - Schwann cell - Satellite cells

Question 33

describe glial pathology

Answer 33

-glioma -largest group of primary tumours derived from glial cells * usually highly malignant * grow rapidly • difficult to remove completely with surgery • Usually inside cranium

Question 34

describe Neuroblastoma

Answer 34

``` tumour (cancer) most common in children & infants • outside cranium • derived from neural crest cells from sympathetic NS •  Catecholamine levels (often) ``` Survival rates vary: depends on type Initial prognosis is typically good Survivors often develop neurological problems ~30 years later • treatment depends on type