Nervous System Flashcards
Which part of the nervous system is involved in the processing of information?
Central nervous system
What makes up the central nervous system?
Spinal cord and brain
What conveys sensory input to the CNS and motor output to the effectors?
Peripheral nervous system
What are the two different parts of the peripheral nervous system?
Somatic and autonomic
What are the two branches of the autonomic nervous system?
Sympathetic and parasympathetic
What are the 3 major components of the brain?
Cerebral hemispheres, brain stem and cerebellum
What are some examples of what the brain stem involved in?
Regulation of CV function, regulation of breathing, regulation of sleep/wakefulness
What is the cerebellum involved in?
Fine aspects of motor control eg juggling, co-ordination
What emerges from the spinal cord?
Around 30 pairs of nerves
What is a ganglion?
Collection of nerve cell bodies in the peripheral nervous system
What are collections of cell bodies in the brain called?
Nuclei
Are ganglia and nuclei equivalent structures?
Yes - ganglia are collections of cell bodies in the PNS and nuclei are collections of cell bodies in the CNS
What are the equivalents of nerves in the central nervous system?
Tracts
What is the white matter of the spinal cord composed of?
Nerve fibres - axons
What is the grey matter of the spinal cord composed of?
Neurones
In which part of the spinal cord does information processing occur?
Grey matter
In which part of the spinal cord does the dissemination of information occur?
White matter
How is grey and white matter distributed in the brain?
Central core of grey matter surrounded by white matter as well as an extra layer of grey matter on the periphery (surface) of the brain - the cerebral cortex
What is the cerebral cortex?
Layer of grey matter surrounding the brain
How do pairs of nerves emerge from the spinal cord?
One emerges dorasally and one emerges ventrally
What is the spinal nerve created by?
The coalescence of the ventral root and the dorsal root - mixed motor and sensory fibres
What function does the ventral root have?
Motor - contains purely motor axons
What function does the dorsal root have?
Sensory - contains purely sensory axons
What is the dorsal root associated with?
Dorsal horn
What is the ventral root associated with?
Ventral horn
What is the dorsal root ganglion?
Swelling in dorsal root - cluster of nerve cell bodies
Where does the cell body of a sensory neurone coming into the spinal chord reside?
Dorsal root ganglion
What is a bipolar neurone?
Neurone with two extensions
Why do impulses travel faster across pseudounipolar neurones?
Impulse can bypass cell body
What is a pseudounipolar neurone?
A pseudounipolar neuron is a kind of sensory neuron in the peripheral nervous system. This neuron contains an axon that has split into two branches; one branch runs to the periphery and the other to the spinal cord.
Where are bipolar neurones often found?
Retina
What do motor neurones consist of?
Cell body, dendrites and axon
What are the 3 classes of neurones?
Sensory neurones, interneurones and motor neurones
What are bundles of axons in nerves called?
Fascicles
What is the connective tissue layer surrounding each individual fascicle?
Perineurium
What is the connective tissue layer surrounding each nerve fibre within the fascicle?
Endoneurium
What is the connective tissue layer that holds all the fascicles together?
Epineurium
What are the two types of cell found in the nervous system?
Neurones and glia
What are glial cells?
Non-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons in the central and peripheral nervous systems.
What do Schwann cells do?
Myelinate axons in the peripheral nervous system
How many axons can one Schwann cell myelinate?
One
What is the main component of myelin sheath?
Membrane lipid - fat - good insulator
How do Schwann cells form the myelin sheath?
The myelin sheath is formed as Schwann cells extend their plasma membranes around the axons of neurons in a spiral fashion.
What do non-myelinating Schwann cells do?
Envelop axons but do not myelinate them - just for support
Which cell type is responsible for myelination in the central nervous system?
Oligodendricytes
Can oligodendricytes myelinate one axon at a time or many?
Many
What do astrocytes create?
Blood-brain barrier which prevents toxins and pathogens from going into the brain from the bloodstream
How do astrocytes create the blood-brain barrier?
Interact with endothelial cells, stimulating them to create tight junctions between them
Aside from forming the blood-brain barrier, what do astrocytes do?
Can send processes out to synapses and ‘vacuum’ up any excess transmitter
What are microglial cells?
Type of glial cell in the CNS with branched processes. They act as surveillance cells to seek out pathogens and when they are activated, they act like macrophages.
