HUBS 191 Lecture 16 Flashcards
(25 cards)
what are the two main types of cells in the nervous system
neurons and glia
where are the nucleus and organelles stored in a neuron
in the cell body - they have lots of ER because they are dynamic and changing all the time
in the CNS what is a bundle of axons called
a tract
in the CNS what is a group of cell bodies called
a nucleus
in the CNS what is a group of cell bodies in the cerebral cortex or spinal cord called
grey matter
in the CNS what is a bundle of axons in the cerebral cortex or spinal cord called
white matter
in the PNS what is a group of cell bodies called
a ganglion
in the PNS what is a bundle of axons called
a nerve
what are the morphological types of neurons
multipolar, bipolar, unipolar and anaxonic (axonless)
what are the four types of CNS glia
astrocytes, microglia, ependymal cells and oligodendrocytes
what are the functions of astrocytes
they supply nutrients to neurons
they cover blood capillaries - make up part of the blood brain barrier
injury response
why do neurons need astrocytes to supply nutrients and how do they do this
because the CNS is segregated from the blood through the blood brain barrier so they can’t get nutrients from blood - astrocytes feed neurons by taking nutrients from the blood stream and taking them to neurons
how are astrocytes involved in injury response
they turn into reactive astrocytes and form a glial scar - they can form a dense network of fibrous tissue that limits the damage when you receive a brain injury
what is the function of microglia
they are the immune cells of the CNS - they engulf microorganisms and debris
what is the function of ependymal cells
they line fluid filled spaces of the brain (ventricles) and spinal cord - they have cilia like processes to circulate CSF
what are the functions of oligodendrocytes
they support nerve fibres - do the same with as astrocytes (feeding neurons) - they also ensheathe them with myelin
what is the myelin sheath and what is its function
lipid (fat) wrapped around the axon many, many times that acts like an insulating membrane. It increases conduction velocity
what are the glia in the PNS called
Schwann cells
what are the functions of Schwann cells
they support the peripheral nerve fibres and ensheathe them with myelin
what are nodes of ranvier
gaps between myelin that increase conduction velocity - they allow the. action potential to propagate down
what is the different between oligodendrocytes and Schwann cells
oligodendrocytes are found in the CNS and Schwann cells in the PNS - also oligodendrocytes can associate with multiple different neurons - or have multiple points of contact with the same neuron
what is the pre synaptic neuron
the neuron before the synapse that releases neurotransmitter and contains synaptic vesicles
what is the post synaptic neuron
the neuron after the synapse thet contains receptors for neurotransmitter
sensory information that goes into the brain is called ____ or ____
afferent - ascending
