neuroanatomy Flashcards
characteristics of neutrons
high metabolic rate, long living and amitotic (don’t divide)
loose chromatin and prominent nucleolus
what are the 3 types of neutron
multipolar- motor
bipolar- retinal nerve fibre (cr 1and 2)
pseudounipolar neuron- sensory neutron
function of myelin sheath
increases conduction sped in axons
what forms the myelin sheath
Schwann cells in PNS
oligodendrocytes in CNS
what is the CNS
brain and spinal cord
clinical importance of myelin sheath
MS- patchy loss/ scarring of myelin sheath and prevents normal nerve conduction
what does white matter contain
myelinated axons
what does grey matter contain
nerve cell bodies
collect of neural cell bodies outside CNS
ganglion
collect of neural cell bodies inside CNS
nucleus
glial cells
non excitable supporting cells, much smaller than neurone
neurons
excitable cells and carry impulses as action potentials
most popular glial cell in CNS
astrocytes- maintaining blood brain barrier
function of microglia
phagocytosis and help with scar tissue formation
function of ependymal cells
line central canal of spinal cord and ventricles
function of satellite cells
surround neuronal cell bodies
describe the blood brain barrier
protective mechanism that helps maintain a stable environment for the brain and prevent harmful amino acids and ions entering the bloodstream and blood cells entering the brain
what forms the BBB
tight endothelial junctions sitting on a basal lamina and is protected by foot processes of astrocytes
what is a circumventricular organ
organs that dont have a blood brain barrier such as the hypothalamus and pituarity gland as they are endocrine organs
function of cerebrum
consciousness
function of cerebellum
balance and coordination, fine tuning motor activity
function of brainstem
vital centres such as cardiorespiratory, pathway for fibre tracts
three parts of brainstem
mid brain, pons, medulla
where does lower end of medulla sit
foramen magnum
3 folds of dura mater
tantrum cerebelli,
dural folds
falx cerebri
what are ventricles in the brain
Spaces in the brain filled with CSF
where do you find the lateral ventricles
c shaped cavities which lie in the cerebral hemisphere
where do you find the third ventricle
cavity within the diencephalon connected by inter ventricular foramen
where do you find the cerebral aqueducts
found in the midbrain
where do you find the diamond shaped 4th ventricles
in the hindbrain- between pons and medulla (in front) and cerebellum ( in back)
where is CSF present
inside ventricles and between Pia and arachnoid mater
where is CSF formed
by choroid plexus in each ventricle
where is CSF absorbed
by arachnoid villi into saggital sinus
where does CSF circulate
around brain and into subarachnoid mater
what is the diecaphelon made up of
thalamus and hypothalamus and pituarity gland
what is the medulla
lowest part of brain stem and at form magnum becomes the spinal cord
what cranial nerves arise from the medulla
9,10,11,12
what is a decussation
crossing over of motor fibres on medulla that carry impulses to skeletal muscle
where does the medulla connect to the cerebellum
inferior cerebellar peduncle
what cranial nerves arise from the pons
5.6.7.8
where does the pons attach to the cerebellum
middle cerebellar peduncle
what are the superior and inferior colliculi
pea like structures on the midbrain and superior gives rise to visual reflex and inferior gives rise to auditory reflex
does 4th cranial nerve originate from the posterior or anterior aspect of the midbrain
posterior aspect
are the structures that make up the diencephalon made up of grey or white matter
grey matter
what does the thalamus do
sensory info synapses in thalamus and it triages it and decides what is most important
functions of hypothalamus
regulating homeostasis
Role of circle of willis
protective feature against vaso-occlusion of large arteries
where do the superficial and deep veins of the brain drain into
venous sinus between dura mater and this drains into IJV
