Cellular and Micro-cellular components of nervous system Flashcards
How much energy consumption does the brain account for
20%
Characteristics of the neuron
Longevity
Do not divide
High metabolic rate
What are the 6 types of glial cells
Astrocytes Microglia Ependymal Oligodendrocytes Schwann cells Satellite cells
Which of the 6 glial cells are neurogliail in the CNS
Astrocytes
Microglia
Ependymal
Oligodendrocytes
What are the ependymal cells
Cells that line the cavities and ventricles of the brain and spinal cord
Can specialise as secretory epithelium and produce cerebrospinal fluid
What is the Blood brain barrier formed by
Astrocytes
What do astrocytes do
Help form BBB
Secrete neurotrophic factors
Provide substrates for ATP production
Take up K+, water, neurotransmitter
What are the microglia
modified immune cells that act as scavengers
What do oligodendrocytes do
form myelin sheath
What is the function of schwann cells
Produce myelin sheath in the PNS Protects and insulates axons Maintains microenvironment Assist neuronal repair Enables Saltatory conduction
What is a unipolar neuron
Single axon
Branches to connect to spinal cord or CNS neurons
Dendrits are where it receives inputs
Have chemically gated ion channels
What neuron would you class as unipolar
sensory neuron
What is a bipolar neuron
SIngle dendrite
SIngle axon
Example of bipolar neuron
sensory neuron in ear, eye and nose
What are multipolar neurons
Single myelinated axon
Multiple densrites
What are multipolar neurons found as
Interneurons
Motor neurons
Explain the pathway of noradrenaline in noradrenergic synapses
SYnthesied in presynaptic terminal from precursors and stored in vesicles
Released after AP
Binds to receptors
Reuptake by presynaptic neuron - reused or broken down by monamine oxidase
What receptors do noradrenaline bind to
alpha2 on presynaptic
alpha1 or beta1 on postsynaptic cell
What is alpha1 receptors involved in
Ocular - mydriasis (dialation)
Blood vessel - vasoconstriction
Male genitals - ejaculation
Bladder, neck and prostate - contraction
What is the alpha2 receptor
Located on presynaptic terminal
Inhibits release of norepinephrine
Located in PNS and CNS
What is beta2 receptor involved in
Bronchi - dialation
Uterus - relaxation of uterine smooth muscle
Arterioles in heart, lungs, skeletal muscles - vasodialation
Glycogenolysis
Enhances skeletal msucle contraction
Passage of adrenalin
Synthesized in adrenal medulla
Stored in vesicles in adrenal medulla
Released into bloodstream after AP
Travels throughout the body but is metabolized by the liver
What is the function of nicotinic receptors
Promotes ganglionic transmission at all ganglia
Causes skeletal muscle contraction
What is the function of muscarinic
Increased gland secretion
Contraction of smooth muscle
Slow heart rate
Contraction of iris and ciliary
