Wk3 Nerves, Synapses and Neurotransmitters Flashcards
The two main nervous systems are?
CNS (Central Nervous System)
AND
PNS (Peripheral Nervous System)
What is included in the CNS?
The brain and Spinal cord.
What is included in the PNS?
The nerves in the body:
- Communication of information to and from CNS
- Regulation of autonomic function
- 12 pairs of cranial nerves and 31 of spinal nerves
What are the two main divisions in the PNS?
Sensory (afferent) division and Motor (efferent) Division
Describe the ‘Somatic’ System (voluntary):
Voluntary control of body movements
Describe ‘Autonomic Nervous System (involuntary):
- Sympathetic (The fright, fight and flight)
- Parasympathetic (Rest and Digest)
A nerve is a _______ of axons - It may be myelinated or ________; sensory, motor or mixed.
A nerve is a ‘bundle’ of axons - It may be myelinated or ‘non-myelinated’; sensory, motor or mixed.
Describe a tract:
Non-enclosed bundle of axons in CNS usually sensory or motor - NOT mixed.
Are ‘Nuclei’ (a) A group of cell bodies underneath white matter in the CNS or (b) Is matter found in the nucleus of a cell, to assist CNS function?
It is:
(a) A group of cell bodies underneath white matter in the CNS.
Ganglion is:
A group of cell bodies outside CNS
Dendrites
Derive from the Greek word “tree” little branches that extend out from the Neuron that relay information to the cell body.
Does an axon transmit information?
Yes, the long arm that transmits information from the other Neurons, muscles and glands.
Myelin Sheath is: (a) Part of the neuron that relays information to other neurons OR (b) Insulating fatty tissue that is around the axons and some neurons.
It is:
(b)Insulating fatty tissue that is around the axons and some neurons.
A synapse is:
The junction or region between the axon of one neuron and the dendrites or cell body of another
What are the 3 types of neurons?
- Sensory Neuron
- Interneuron Neuron (Relay)
- Motor Neuron
Describe the role of the Sensory Neuron:
Carries impulses from receptors (eg. pain receptors in skin) to the CNS (brain or spinal cord)
Describe the role of the Interneuron:
Carries impulses from sensory nerves to motor nerves.
Describe the role of the Motor Neuron
Carries impulses from CNS to effectors
eg. muscle (to bring about movement) or glands (to bring about secretion of hormone eg. ADH)
Another word for Glial cells is: ________
And what does it do?
‘Neuroglia’
Neuroglial cells support, insulate and protect neurons.
Glial cells found in the CNS are:
- Oligodendrocytes: produce the myelin sheath.
- Astrocytes: Star shaped cells. That form the blood-brain barrier.
- Ependymal cells: These are the columnar epithelial cells covering the ventricles of brain and canal of spinal cord.
- Microglia cells: These are small, mesodermal, elongated cells. They are derived from precursor cells in the bone marrow, and are phagocytic.
Glial cells found in the PNS are:
- Schwann cells: Surround all axons; responsible for myelination of peripheral axons. They participate in the repair process after injury.
- Satellite cells: Surround neuron cells bodies in ganglia: regulates oxygen and carbon dioxide nutrients, and neurotransmitter levels around neurons.
Main features of the neuron structure:
- Dendrites: carry impulses towards the cell
- Axon: carry impulses away from the cell
- Myelin sheath:insulation, rapid conduction
- Synaptic terminal:vesicles with NT (eg. noradrenaline, adrenaline, acetylcholine)
What is neurotransmitters? Name the two types of functions.
Chemicals used for neuronal communication with the body and the brain.
Chemically through: Acetylcholine, Biogenic amines, Peptides etc.
Functionally eg. Excitatory or inhibitory
Two forms of actions that NT produces:
Excitory:
Inhibitory:
Electrical Synapses is:
Gap junction: that allow local current to flow.
Chemical Synapses has 3 components name them:
- Presynaptic terminal
- Synaptic cleft
- Postsynaptic membrane
Is ACh synthesised in CNS and PNS?
Yes, ACh is a NT used by the spinal cord neurons to control muscles.
