Cells and Tissues of the Nervous System Flashcards
what are neurons?
Structural and functional unit
Excitable cells
Impulses carried as action potentials
what are glial cells?
Non-excitable supporting cells
Much smaller than neurons
Which of these describes
A typical neuron:
Multiple dendrites, one axon
Multiple axons, 1 dendrite
multiple dentrites, one axon
Which of these choices describes a typical neuron:
in either direction across a neuron
in only one direction from synaptic terminals to cell body
in only one direction from cell body to synaptic terminal
in only one direction from cell body to synaptic terminal
what are dentrites stimulated by?
environmental changes or the activities of other cells
what does the cell body of a neuron contain?
contains the nucleus, mitochondria, ribosomes, and other organelles
function of the axon
conducts nerve impulse toward synaptic terminals
function of the synaptic terminal
affect another neutron or effector organ
what are the different types of neutrons?
multipolar, bipolar and pseudounipolar
true or false:
neurons have a low metabolic rate
false they have a high
function of a myelin sheath
increase conduction speed in axons by saltatory conduction
what is the myelin sheath formed by?
schwaan cells in PNS and oligodentricytes in CNS
what does a loss/scarring of myelin sheath cause?
nerve conduction across affected axons which are abnormal
what is the blood brain barrier?
protective mechanism that helps maintain a stable environment for the brain and prevents harmful amino acids and ions present in the bloodstream and blood cells from entering the brain
what are the contents of a blood brain barrier
endothelium- tight junction
thick basal lamina
foot processes of astrocytes
what circumventricular organs have the blood brain barrier?
parts of the hypothalamus and posterior pituitary
what other role does the blood brain barrier play?
major role in drug delivery to CNS. Drugs have to be lipid soluble or use suitable vectors
what shape are the lateral ventricles and where do they lie?
C shaped and lie in the cerebral hemisphere
what does the interventricular foramen connects with?
the 3rd ventricle- the cavity
where does the cerebral aqueduct lie?
lies in the hindbrain
what shape is the 4th ventricle?
diamond
where does the 4th ventricle lie?
in hindbrain
what are the ventricles called within the cerebral hemisphere?
lateral ventricles
what is the ventricle called within the diencephalon
III ventricle
what is the ventricle called within the midbrain
cerebral aqueduct
what is the ventricle called between pons and medulla and cerebellum?
IV ventricle
what are the 3 meninges?
dura mater, arachnoid mater, pia mater
what is the texture of dura mater?
tough, fibrous and has dural folds
what is significant about the pia mater?
its vascularised and dips into the folds of the brain
what is the subdural space?
is a potential space which is tranversed by blood vessels penetrating intp the cns
what dpes the subarachnoid space contain?
cerebrospinal fluid
what to some extent is responsible for the maintanence of the iintracrainial pressure?
CSF
where is the CSF present?
inside ventricles and between pia and arachnoid
where is the CSF formed?
by choroid plexus in each ventricle
where is the CSF absorbed?
by arachnoid villi into saggital sinus
