Central Nervous System I Flashcards
Describe the components of the CNS
Made up of the brain and spinal cord
Describe the components of the peripheral nervous system (PNS)
Nerves from CNS to organs
Divided into somatic, autonomic and enteric NS
Describe the difference between neurons and glial cells
Neurons - Excitable cells
Glial - Non-neuronal support cells
What is a soma?
Contains nucleus and most organelles
What are dendrites?
Reception of incoming information
What are axons?
Transmit electrical impulses (AP)
What is an axon hillock?
Where axon originates and AP initiated
What is an axon terminal?
Releases NTs
Note: Most neurons are non-divided
What are the components of a neuron?
Presynaptic - Dendrites, cell body (soma), nucleus, axon hillock, axon, axon terminal
Synapse, dendrites,
Postsynaptic, collateral axon, axon terminal
What is the node of Ranvier?
Area of polarity reversal
What are the different structural classes of neurons?
Bipolar, Pseudo-unipolar and multipolar
Describe the difference between bipolar, pseudo-unipolar and multipolar
Bipolar - Has one axon and one dendrite extending from the soma
Unipolar - Has one structure that extends away from the soma
Multipolar - Has one axon and multiple dendrites
Describe the functional classes of neurons in terms of input
Sensory/visceral receptors in PNS input signal via afferent neuron along peripheral axon by unipolar neuron to CNS interneurons
Describe the functional classes of neurons in terms of output
Interneurons in CNS send signal to cell body towards PNS to effector organs via efferent neurons by multipolar neurons
Describe afferent neurons
Carries impulses to CNS, for sensory function
Describe efferent neurons
Carry impulses in opposite direction away from CNS, for motor function
Describe interneurons
99% of all neurons in body (Only in CNS)
CNS integrate sensory info, Initiate/Coordinate efferent responses
Describe the functional association of neurons
Neuron-Neuron in CNS
Effector organs in PNS (muscle/gland)
What are the types of neurons functionally associated?
Electrical
Chemical (All neurotransmission is chemical)
Describe the communication across a synapse
Action potential Voltage-gated Ca channels open Ca triggers exocytosis NT diffuses/binds to receptor Response in cell, terminated by removing NT from synaptic cleft Degradation Re-uptake Diffusion
What are the types of neuron-neuron synapses?
Axodendritic synapse - Pre axon to post dendrite
Axosomatic - Pre axon to post soma
Axoaxonic - Pre axon to post axon
Describe the structural organisation of neurons in the nervous system
In CNS: Nuclei - Group of cell bodies
Pathways, tract, commissures - Bundles of axons
In PNS: Ganglia - Group of cell bodies
Nerves - Bundle of axons
What are the different types of glial cells in the CNS?
Astrocytes, Ependymal, Microglia, Oligodendrocytes
Describe astrocytes cells
Most abundant cell in human brain, communicate via gliotransmission/gap junctions
