Lecture 5 Neural Tissues

Question 1

what is the purpose of the nervous system

Answer 1

communication leading to sensory detection. Via information processing to motor activity to behaviour

Question 2

what is the CNS

Answer 2

brain and spinal cord

for information processing, including reflexes and behaviour

Question 3

what is the PNS

Answer 3

Peripheral or parasympathetic

sensory detection and motor activation

Question 4

why is the nervous system complex

Answer 4

many cells
10^11 neurons, 10^14 synapses, 1.5 kilograms in brain
10^8 neurons in enteric NS (More than spinal cord)

Question 5

what is an afferent neuron

Answer 5

transmit sensory info to brain/spinal cord

ARRIVES

Question 6

What is an efferent neuron

Answer 6

motor neurons transmitting info from brain to effector organ eg muscle
EXITS

Question 7

what is a ganglion

Answer 7

group of cells outside the CNS
eg motor ganglion (autonomic)
basal root ganglia is an exception

Question 8

what is a parasympathetic ganglion like

Answer 8

smaller neurons and eccentric nuclei

Question 9

what is a sympathetic ganglion like

Answer 9

eg dorsal root ganglia

big neurons and central nuclei

Question 10

how is the human prefrontal cortex navigated

Answer 10

Dorsal – lateral axis bends
Rostral – caudal axis bends
curves through head, front R, back C, top D, bottom V

Question 11

what are the Brodmann areas of the neocortex

Answer 11

regions of cortex numbered 1-52
Each area has a particular set of inputs and outputs.
Often an area will have a function

Question 12

what does Brodmann area 4 do?

Answer 12

primary motor cortex

Question 13

what does brodmann area 17 do?

Answer 13

primary visual cortex

Question 14

what is a CNS neuron like

Answer 14

nucleus within cell body and extends one or more processes

Question 15

what are the parts of a CNS neuron

Answer 15

dendrites
cell body
axon hillock to axon with axon collaterals, nodes of ranvier, myelin sheath
axon terminals

Question 16

what is the myelin sheath

Answer 16

many layers of cell membrane wrapped around an axon

Question 17

what does myelin do

Answer 17

electrically insulates to increase diameter and conduction velocity
breaks - nodes of ranvier

Question 18

what are the classifications of neurons

Answer 18

multipolar - several dendrites, majority
bipolar - one dendrite and axon either side of cell body
unipolar - or pseudo, one axon and dendrite in single branching process as 2 processes move together
all axons have just one neuron

Question 19

what are other important neurons

Answer 19

pyramidal cells (axon either side of cell body with dendrite - neocortex - thinking)
purkinje cell (small and many, lots of interactions - cerebellum)
Dorsal Root Ganglion (psuedounipolar, sensory neuron)

Question 20

what is a synapse

Answer 20

a functional link

Question 21

what are post synaptic cells

Answer 21

neuron, myocyte or glands

Question 22

what is a chemical synapse like

Answer 22

big gap -30nm
common in NS
signalling not in retrograde direction

Question 23

how to pre and postsynaptic cells interact

Answer 23

presynaptic cell releases neurotransmitter

post synaptic cell is the receptor, turns it to electric signal

Question 24

what is a divergent neuron

Answer 24

a single neuron sending its output signal to many neurons eg skin

Question 25

what is a convergent neuron

Answer 25

multiple inputs influence a single neuron eg retina

Question 26

what are interneurons

Answer 26

occur only in CNS can be excitatory or inhibitory they process signals connect sensory to motor neurons in DRG

Question 27

what do glia do and not do

Answer 27

no action potentials and do not form synapses | can divide and form myelin sheaths

Question 28

how do neurons and glia compare

Answer 28

neurons are basic nerve cells, impulse conducting and glia are supportive and protective 1 neuron to every 10-50 glia

Question 29

what are the glial cell types

Answer 29

``` ependymal cell astrocyte pia matter microglial cell oligodendrocyte ```

Question 30

what do oligodendrocytes do

Answer 30

produce/maintain myelin sheath in CNS | one myelinates multiple axons from different neurons

Question 31

what do astrocytes look like

Answer 31

star shaped | its 'feet' on processes about bv endothelium

Question 32

what do astrocytes do in CNS

Answer 32

influence blood flow and blood-brain barrier assist neuronal development/growth (neurotrophic) protect neurons from harmful substances

Question 33

what do microglia cells do in CNS

Answer 33

Immune cells to protect neurons from disease, migrate to injury sides, engulf microbes/debris, mesodermal growth

Question 34

where do microglia come from

Answer 34

mesoderm like other immune cells

Question 35

what do ependymal cells do in CNS

Answer 35

line brain ventricles and central canal of spinal cord form CSF cilia and microvilli on apical membrane

Question 36

what do Schwann cells do in the PNS

Answer 36

production and maintenance of myelin sheath in PNS 1 axon per Schwann cell (axons have many Schwann cells) analogous to oligodendrocytes

Question 37

what do satellite cells in the PNS do

Answer 37

support neurons, regulate exchange of materials between neurones and interstitial fluid analogous role to astrocytes

Question 38

what glia are in the CNS

Answer 38

astrocyte oligodendrocyte ependymal cell microglial cell

Question 39

what cells are in the PNS

Answer 39

Schwann cells | satelite cells

Question 40

what are the 3 layers of the meninges

Answer 40

3 meningeal layers – Dura matter, Arachnoid, Pia matter (inner most)

Question 41

what is a glioma

Answer 41

``` glia pathology largest group of primary tumours from glial cells usually highly malignant grow rapidly difficult to completely remove usually inside cranium ```

Question 42

what is a neuroblastoma

Answer 42

``` neural pathology cancer most common in kids and infants outside cranium from neural crest cells in sympathetic NS survival rates vary but initial prognosis typically good treatment varies on type many develop neural issues in 30's ```

Question 43

what is a sign of neuroblastoma

Answer 43

increase in catecholamine levels