4 - Nerves Flashcards
a lot of _____ praise from the brainstem
cranial nerves
the brainstem is primarily made up of _____ matter
grey
Structurally, what is the cerebellum?
hindbrain structure attached to the brainstem
Where are unipolar cells found in the NS?
(Rarely found in the CNS)
around the retina
What is a pseudo-unipolar cell and where is it found in the NS?
has a single axonal projection which splits into two
rarely found in the CNS
mainly found in the pain pathway in the PNS
What is a bipolar cell and where is it found in the NS?
two projections - 1 axon and 1 dendrite
rarely found in the CNS
What is a multipolar cell and where is it found in the NS?
numbers projections coming form the cell body - 1 axon and multiple dendrites
very common
have many morphologies
What are the three types of multipolar cells? Where are they found?
Pyramidal, Golgi and Purkinje
Pukinje and Golgi are the GABA neurones found in the cerebellum
Where does an axon originate from?
the soma at the axon hillock
What can axons branch into?
collaterals
Give some characteristics of neurones
- excitable cells
- heterogenous morphology
- non-dividing cells
- 3 parts: soma, axon and dendrites
are dendrites myelinated?
NO
What is neuroglia/glia?
the connective tissue of the nervous system, consisting of several different types of cell associated with neurons
(all other cells of the NS except neurones)
What is the most abundant cll type in the mammalian brain?
astrocytes
What is the main difference between oligodendrocytes and schwann cells?
one oligodendrocyte myelinated many axons
one Schwann cell myelinated one axon segment
oligodendrocytes - in the CNS
schwann cells - in the PNS
What are ependymal cells and what is their function?
the epithelial cells of the CNS
they line fluid filled ventricles and regulate production and movement of cerebrospinal fluid
Compare the concentration of chloride ions intracellularly and extracellularly
higher extracellular concentration
Compare the concentration of calcium ions intracellularly and extracellularly
in very low concentrations
higher extracellularly
very steep concentration gradient
What properties of myelin prevent the spread of an AP?
high resistance
low capacitance
Give the sequence of events of neurotransmission at a synapse
- when the AP arrives the the presynaptic membrane, depolarisation causes the opening of VGCCs, leading to an influx of Ca2+
- Ca2+ causes vesicular exocytosis
- neurotransmitter binds to receptors on the post-synaptic membrane
- neurotransmitter reuptake:
1 - metabolised by enzymes in the synaptic cleft and taken back up by the axon terminal
2 - recycled by transporter proteins
