Neurology 1 Flashcards
what two types of fibres are contained in the motor efferent division ?
somatic
autonomic
what are the two types of cells in the nervous system ?
neurons
glial cells
state two characteristics of neurons
- excitable
2. carry action potentials
state two characteristics of glial cells
- non-excitable
2. much smaller than neurons but there are a lot more in number
what are the four parts of the neuron called ?
dendrite
cell body
axon
synaptic terminals
how many dendrites are there in a neuron?
multiple
in which direction does the action potential travel in a neuron?
from dendrites to the synaptic terminals
what is the area of the cell body in a sensory neuron called ?
dorsal root ganglion
are neurons amitotic ?
yes
what organelles are present in neurons ?
- lots of mitochondria
- lots of rER
- lots of golgi apparatus
do neurons have a slow or fast metabolic rate?
fast
why do neurons require lots of mitochondria and rER?
many neurotransmitters are produced all the time so a to of energy has to be produced for the large number of proteins which need to be produced
what is the cytoplasm in the cell body called?
perikaryon
what is the cytoplasm in the axon called?
axoplasm
under what condition can the axon grow back?
if the cell body is not damaged
when a nerve is myelinated, what is the conduction called?
saltatory conduction
what are the gaps in-between the myelin on a nerve called?
nodes of ranvier
what produces the myelin sheath in the
- PNS
- CNS ?
PNS = schwann cells CNS = oligodendrocytes
how is the myelin sheath formed by these cells?
the cells wrap their cytoplasm around the axon of the nerve
what is formed in a myelinated axon?
mesaxon
what is the main pathology of multiple sclerosis ?
Patchy loss/scarring of myelin sheath (demyelination)
= decreased nerve conduction
what shows on the MRI of a MS patient?
whitish plaques of demyelination
what country has the highest incidence of multiple sclerosis in the world ?
scotland
what are the three types of neurons ?
multipolar
bipolar
pseudo unipolar
what type of neurons are motor neurons ?
multipolar
what type of neurons are sensory neurons ?
pseudo unipolar
what are collection of cell bodies in the PNS called ?
ganglia
what are collection of cell bodies in the CNS called ?
nucleii
what are collection of myelinated axons in the CNS called ?
tracts
what are collection of myelinated axons in the PNS called?
nerves
how many different types of glial cells are there?
6
where are astrocytes from in the body?
surround capillaries
what two glial cells are found in the PNS?
schwann cells
satellite cells
what are the four main areas of the brain called?
- cerebrum
- cerebellum
- brain stem
- diencephalon
what two things is the cerebellum involved with?
balance and coordination
which layer of the trilaminar plate forms the neural tube?
ectoderm
what forms the glial cells?
neural crest cells
what are the four main areas of the neural tube ?
- prosencephalon (fore)
- mesencephalon (mid)
- rhombencephalon (hind)
- spinal cord
the forebrain vesicle called prosencephalon forms what two vesicles ?
telencephalon
diencephalon
how many primary vesicles are there in the brain development ?
3
how many secondary vesicles are there in the brain development ?
5
what structure forms from the diencephalon ?
the eyes
state the four ventricles in the brain
Lateral ventricles sitting on each side of the mid line in the cerebral brain
3rd ventricle
Cerebral aqueduct (doesn’t grow very much so very small space)
4th ventricle (diamond shape)
what fluid circulates the ventricles ?
CSF
what does CSF stand for?
cerebrospinal fluid
what are the three meninges of the CNS?
dura mater
arachnoid mater
pia mater
between which 2 layers does the CSF sit?
arachnoid and pia mater
which meninges layer is most deep?
pia mater
where is CSF formed?
choroid plexus in each ventricle
where is CSF absorbed ?
By Arachnoid villi into saggital sinus (venous channel in brain)
where two locations is CSF present?
inside ventricles
in subarachnoid space
what is the dural fold which splits the two hemispheres of the cerebrum?
falx cerebri
what is the function of the dural folds in the brain?
- ensure the brain remains in the correct position
what is the dural fold called which covers the pituitary gland?
diaphragma sellae
what is the function of the blood brain barrier ?
protective mechanism which maintains homeostasis in brain parenchyma
how are the epithelium cells joined in the brain?
tight junctions
is the BBB present in the whole brain?
no
few circumventricular’ organs don’t contain the BBB such as
- parts of hypothalamus
- posterior pituitary
what is the clinical significance of BBB in the CNS?
Drugs which act on the brain have to be lipid soluble or use suitable vectors.
