Cells and tissues of the nervous system Flashcards
What are the only 2 type of nervous system cell types?
neurons and glial cells
Are neurons or glial cells exciteable cells?
neurons
How are impulses carried in a neuron?
as an action potential
Compare the number and size of neurons and glial cells
glial cells are smaller and more plentiful
Are there multiple axons or dendrites in a neuron?
dendrites
What direction do impulses travel along a neuron?
cell body to synaptic terminal
What is the reason for a lot of mitochondria and rER in neurons?
high metabolic rate and to package proteins
What does amitotic mean?
if it dies will not regenerate itself
Can the axons or cell bodies regenerate if damaged?
axons
Saltatory conduction
increase speed of impulse as action potential can jump the nodes of ranvier
myelin sheath formed from what?
glial cells - oligodendrocytes in the CNS and schwann cells in the periphery
How do the glial cells form the myelin sheath
secrete their cell membrane
What happens to the myelin sheath in multiple sclerosis?
patchy loss/scarring –> demyelination and abnormal nerve conduction
Cause of MS and epidemiology
viral or autoimmune?
Scotland has the highest incidence
MRI - what is seen in MS?
whitish plaques of demyelination
Name the 3 types of neurons
multipolar, bipolar, pseudounipolae
What neuron has the cell body in olfactory bulb?
bipolar
What pathways are bipolar neurons used in?
olfactory mucosa, retinal fibres - special sense
What type of neuron is regarded as the “typical” neuron?
multipolar
Are multipolar neurons sensory or motor neurons?
motor mostly
Are pseudounipolar motor or sensory?
sensory
Where does a pseudounipolar neuron cell body lie?
in dorsal root ganglia outside of the CNS
What are axons bundled together depending on?
information they carry
collection of cell bodies and non myelinated axons in the CNS (2)
diffuse = grey matter localised = nuclei
Collection of myelinated axons in the CNS (2)
diffuse = white matter
bundles carrying specific information within white matter = tracts
myelinated axons in periphery
nerves
cell bodies in periphery
gangia
2 types of glial cells found in the periphery?
schwann cells and satellite
4 types of glial cells found in the CNS?
astroctytes, oligodendrocytes, microglia, ependymal cells
What do ependymal cells line?
ventricles
What are the thalamus and hypothalamus a part of?
diencephalon
What tube goes on to form the nervous system?
neural tube
how many primary and secondary vesicles are there?
3, 5
What are the 3 primary vesicles called?
forebrain, midbrain and hindbrain
What fluid do the ventricles contain?
CSF
What part of the brain does the forebrain form?
diencephalon and cerebrum
What part of the brain does the hindbrain form?
pons and medulla
cerebellum
telencephalon - what ventricle?
lateral ventricles
diencephalon - which ventricle?
3rd ventricle
midbrain - which ventricle?
cerebral aqueduct
hindbrain - which ventricle?
4th
What does the interventricular foramen connect
lateral and 3rd ventricle
What part of the adult brain are lateral ventricles found?
cerebral hemispheres
What part of the adult brain is the interventricular foramen found?
diencephalon cavity
cerebral aqueduct found where in the brain?
midbrain
What part of the brain is the 4th ventricle found?
hindbrain with the cerebellum at the back
What are the 3 layers of mater?
dura, arachnoid and pia
Describe dura mater
tough, fibrous, outer layer - dural folds
Pia mater description
vascularised and dips into folds of the brain
2 spaces between the mater?
subdural and subarachnoid
What does the subarachnoid space contain?
CSF
subdural space - what is important about this?
potential space with blood vessels for the CNS
CSF function
maintain intracranial pressure
Where is CSF found?
inside ventricles and between pia and arachnoid mater
Where is CSF formed?
choroid plexus in the ventricles
Where is CSF absorbed?
arachnoid villi into saggital sinus
How does CSF get into the subarachnoid space from the ventricles?
lateral aperture of the 4th ventricles and foramen
What are the 4 dural folds you need to know?
falx cerebri, tentorium cerebelli, falx cerebelli and diaphragm sellae
falx cerebri location
between cerebral hemispheres
tentorium cerebelli location
separates the cerebellum from the cerebrum
falx cerebelli location
between cerebellar hemispheres
diaphragm sellae goes around what?
pituitary stalk
3 parts of the blood-brain barrier
tight junction - endothelium
thick basal lamina
foot process of astrocytes
What types of organs is the blood-brain barrier absent?
circumventricular
What solubility must drugs have to be delivered to the CNS?
lipid
