Cells and Tissue of the Nervous system Flashcards
What is the central nervous system and periphery nervous system composed of
CNS- Brain and spinal cord
PNS- cranial and spinal nerves
What is the divisions of the PNS
Sensory - afferent
Motor - efferent
What is the further division of Efferent PNS
Somatic - voluntary
Autonomic - involuntary (sympathetic/parasympathetic)
What is the two cell types found in the neurosytem
Neurons - excitable cells
Gilal cells - nonexcitable supporting cells
What is the features and structure of a typical neuron
Composed of multiple dendrites
cell body
One long axon
and a sympathetic terminal
With AP traveling from the cell dendrites to sympathetic terminals
What is the 3 different types of neurons
Multipolar
Bipolar
Pseudounipolar
What type of neurone is the most typical motor neurone
Mutipolar
What type of neurone is pseudo unipolar
Sensory neurone
What is the important about the structure of pseudo unipolar
Dendrite passes onto to axon directly as celll body sits outside central nervous system - ganglion
What kind of neurone is bipolar
specialized sensory neurons for the transmission of special senses
(smell, sight, taste, hearing and vestibular functions)
Were are bipolar neurons found
Olfactory mucosa
Retinal nerve fibres
What features of neurone allow it to have a high metabolic rate
Prominent Nucleus with loos chromatin
Mitochondria
rER
Golig apparatus
What is the cytoplasm in the cell body and axon called
Cell body - perikaryon
axon - axoplasm
What is features of neurones
Long living
Axon has the potential to grow bak
Amitotic - cant do mitosis (cell body damage is irreversible)
What is the purpose of the myelin sheath (the envelope around the axon
increases conduction speed in axons by saltory conduction
How does salutary conducting occur
AP jumps from node of raniver to next node
What is similarity and differences between myelinated and non myelinated axon
Both axons have schwann cells wrapped around
but in nonmyelinated axon still wrapped by schwann cells but myelin sheath is not formed
What produces myelin sheath
Schwann cells (PNS)
Oligodendrocytes (CNS)
What disease shows the clinical importance of myelin sheath
Multiple sclerosis
What occurs in multiple sclerosis and what is the affect of this
Patchy loss/scarring of myelin sheath = demyelination
meaning nerve conduction across affected axons is abnormal
What is a good investigation for multiple sclerosis
MRI as shows plaque with demyelination
What is the name of a myelinated axon
mesaxon
Why don’t pain and sensory follow the same path
As have different tracts
Define tracts
bundles of axons carrying specific information within the white matter = fibre pathways
What forms the grey matter in the CNS
Cell bodies and non myelinated axons
What forms the white matter in the CNS - why is it white?
Myelinated axons
white as myelin (from membrane lipids) colours the matter
What forms the myelinated axons and cell bodies in the periphery
nerves and ganglions
What is a collection of cell bodies called in the central nervous system
Nuclei
What is a collection of cell bodies outside the CNS called
Ganglion
What is the 4 glial cells found in the CNS
astrocyte
oligodendrocyte
Microglia
ependymal
Function fo astrocyte
Covers the synapse and capillaries
Forms blood brain barrier
- help in K+ buffering
What is the function of microgilal
Phagocytees
scar tissue formation
What is the function of ependymal
Line ventricles
What is the two Glial cells found in the PNS
Satellite cells
Schwann cells
What is the function of satellite cells
Surround neuronal cell bodies
What is 4 big parts of the brain
cerebellum
Cerebrum
Diencephalon
Brainstem
What is the three parts of the brain stem
mid brain
pons
medulla
Where does the cranial nerve comes from
Brain stem
What does the cavity inside the neural tube from in the development of the nervous system
Ventricles
How many ventricles are formed and what are they called
2 lateral ventricles
3rd ventricle
Cerebral aqueduct
4th Ventricle
Where is the lateral ventricles found
Cavity in the cerebral hemisphere
Where is the third ventricle
Cavity in the diencephalon
What is the smallest ventricle and where is it located
The cerebral aqueduct
Found going down the middling e
Where is the fourth ventricle exactly located
In the hindbrain
between the cerebellum posteriorly and the pons/medulla anteriorly
As soon as the neural tube forms what does it divided into and then further divide into
3 primary vesicles and then 5 secondary vesicles
What is the 3 primary vesicles
Prosencephalon - Forebrain
Mesencephalon - Midbrain
Rhombencephalon - Hindbrain
What is the 5 secondary vesicles
Telencephalon - forebrain
Diencephalon -forebrain
Mesencephalon - midbrain
Metencephalon -hindbrain
Myelencephalon - hindbrain
What does the telencephalon in the forebrain develop into
The cerebral hemisphere
What does the diencephalon in the forebrain develop into
Thalamus and hypothalamus
What does the hindbrain
(Metencephalon + Myelencephalon) develop into
Pons and medulla
and the cerebellum at the back
What does the Mesencephalon develop into
the midbrain
Where is CSF found
Inside the ventricles
Centre canal of spinal cord - between pia and arachnoid
Where is CSF formed
Fomred in the chord plexus in each ventricle
a thin vascular structure
What is the function of the CSF
Responsible for the maintenance of the intracranial pressure
What is the circulation of the CSF
Circulates ventricles then leave ventricular space between thin layer at the roof of the 4th ventricle Via 3 holes where it goes into the subarachnoid space in the spinal cord
How and Where is the CSF absorbed
By the arachnoid villi into sagittal sinus
What is it called when arachnoid villi join together
Granulation Arachnoid
