T1L4:Neural Tissues Flashcards
what are the differences between the PNS and CNS
CNS:
-Brain and spinal cord
- Information processing
- including reflexes and behaviour
PNS:
- Sensory detection
- motor detection
which embryonic layer does the NS come from
-the ectoderm
what is the difference between an afferent and efferent neuron
- afferent: : transmit
sensory information to
brain/spinal cord
efferent :: motor neurons transmitting information from brain to effector organ i.e. muscle
what is a ganglion
group of cell bodies outside the CNS
give examples of ganglions
- dorsal root ganglion
- sensory ganglion
describe the motor ganglion
autonomic
describe the parasympathetic ganglion
- smaller neurons
- eccentric nuclei
what is the equivalent of ganglia in the brain
- Nuclei/nucleus: In CNS groups of neurons called “nucleus”
go over slide 10:
Directions in human prefrontal cortex
- how was it
what is the significance of Brodmann areas
Each Brodmann area has a particular set of inputs and outputs.
Often a Brodmann area will have a function
what is Brodmann area 4 and 17
4: ~primary motor cortex
17: primary visual cortex
what is the CNS neuron
: nucleus within cell body and
extends one or more processes
what is a process of a neuron
-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).
go over slide 12:labelling of a neuron
how was it
describe the function of the myelin sheath
Electrically Insulates.
increasing conduction velocity
structure of myelin sheath
Made of many layers of cell membrane
what are the different neural classifications
multipolar, bipolar and unipolar
what are the important neurons
1- pyramidal cell-neocortex
2- purkinje cells-cerebellum
3- Dorsal root ganglion-sensory neuron
difference between a bipolar neuron and a pseudo-unipolar neuron and give e.g. of each
Bipolar:
- 1 dendrite
- 1 axon
- least numerous
- sensory neurons
- e.g.- retina
pseudo-unipolar:
- 1 axon
- 1 dendrite
- e.g. dorsal root ganglion
what is a chemical synapse
-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
what is the difference between convergent and divergent
-Divergent- A single neuron sends its output signal to many neurons
E.g. Skin
convergent:multiple inputs influence a single neuron
E.g. Retina
describe interneurons
Interneurons occur only in CNS.
They are neither motor nor sensory.
They process signals
how do neurons differ from glia
-glia:
- have no AP
- Are able to divide
- don’t form synapses
- form myelin sheaths
what are the roles of glial cells
- supportive
- protective
-go over slide 24 for the different types of glial cells
-how was it
describe oligodendrocytes
- production / maintenance of
myelin sheath in CNS
-1 oligodendrocyte myelinates multiple axons (from different neurons)
describe astrocyte function
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
describe the microglia
-immune cells, protect
neurons from disease, migrate
to injury sites, engulf microbes
/ debris, mesodermal origin
describe ependymal cells
-line brain’s ventricles and central canal of spinal cord,
form CSF
-made up of cilia + microvilli on apical membrane
describe schwann cells (PNS)
-production / maintenance of
myelin sheath, PNS
regeneration
-1 axon wrapped per Schwann cell,Compare to oligodendrocytes (in CNS)
describe satellite cells
- support neurons, regulate exchange of materials between neurons and interstitial fluid
- Perform analogous role in PNS to what astrocytes do in CNS
how do you classify glia
Central Nervous System:
- Astrocyte
- Oligodendrocyte
- Ependymal cell
- Microglial cell
Peripheral Nervous System:
- Schwann cell
- Satellite cells
describe glial pathology
-glioma
-largest group of primary tumours
derived from glial cells
- usually highly malignant
- grow rapidly
• difficult to remove completely with
surgery
• Usually inside cranium
describe Neuroblastoma
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
