Neurophysiology Flashcards
(39 cards)
What is the difference between the structure and function of the nervous system
Structure = Anatomy
–> CNS and PNS
Function = Physiology
–> Neurons and processes
What are the two general functions of neurons?
- Conduct action potentials (conduct electrical signals)
- Releaser and send neurotransmitters (conduct chemical signals)
What are the three general functions of the nervous system?
- Control of movement = motor control
- Detection of external stimuli = sensory control
- Intergration of neuronal activity = association
How are the functions of neurons classified?
Classified based on the direction of their impulses (action potentials + neurotransimitters)
What are the 3 functional classifications of neurons?
- Sensory/afferent
- Association/interneurons
- Motor/efferent
How does the sensory function of neurons work?
Directs impulses from detected by the sensory receptors into the central nervous system
How does the association and interneuronal activity work?
Activity is based solely in the central nervous system, and helps integrate the CNS functions (directing neuron-neuron activity)
How does the motor/efferent function work?
Directs impulses from the sensory receptors out of the CNS to the target effector organ (ex; muscles)
How is the motor/efferent function split/organized?
Split into 2 groups, somatic and autonomic.
Somatic relates to voluntary and reflexive movement (scratching ear)
Autonomic relates to involuntary movement (ex; heart beat and digestion)
How is the autonomic NS organized?
Split into sympathetic and parasympathetic NS
Sympathetic relates to the bodily functions and organs involved in the fight/flight response
Parasympathetic relates to the bodily functions and organs involved in the rest/digest response
How do the sympathetic and parasympathetic nervous system relate to each other? (think general)
They both have opposing actions/mediate opposing responses in effector organs
What does the somatic nervous system do/involve?
Involves only 1 neuron and conducts impulses along 1 axon
Conducts activity from cell bodies in neurons from the CNS and sends them across the axons to the skeletal muscles
What does the autonomic nervous system do/involve?
Involves 2 neurons in an efferent pathway
1st neuron = preganglionic neuron
2nd neuron = postganglioninc neuron
What does the preganglionic neuron from the autonomic NS do? (general)
Where is it found?
Most commonly found in cell bodies of neurons in the CNS - grey matter (brain/spinal cord)
Does not directly innervate the effector organ but synapses with the 2nd neuron
Synapsing w/ 2nd neuron is exclusive to only preganglionic neurons
What does the postganglionic neuron do? (genral)
Synapses with the target effector organ, and regulates activity by sending neurotransmitters
- Its axon extends from the autonomic ganglia (nerve cells outside of CNS) to the effector organ
What neurotransmitter(s) are released by the preganglionic neuron?
What does it do?
All preganglionic neurons release acetylcholine and therefore are cholinergic neurons as well.
Acetylcholine is involved in the rest and digest processes
What neurotransmitter(s) are released by the postganglioninc neuron?
What does it do?
Can release both acetylcholine and norepinephrine, there is both a cholinergic and adrenergic neuron.
Norepinephrine is involved in the fight/flight processes
Which nerve fibers mostly release acetylcholine in the NS
Acetylcholine is mostly released by the parasympathetic postganglionic fibers
Which nerve fibers mostly release epinephrine in the NS
Norepinephrine is released by most sympathetic nerve fibers
What are two main diseases that are caused by dysfunction in the autonomic NS
Lyme disease
POTS
What are the 4 structural classifications of neurons?
What do they do/function?
- Pseudopolor/unipolar - sensory neurons, 1 process that splits
- Bipolar - 2 processes (ex; retinal and cochlear)
- Multipolar - most common, motor + association neurons, contains many dendrites but only 1 axon
- Anaxonic - no obvious axon, includes some CNS neurons
What are the supporting nerve cells involved in the peripheral nervous system?
What do they do?
- Schwann cells - Form myelin sheaths around axons (successive wrapping around 1 axon); provides insulation (increase firing speed)
- Satellite cells - Provide support to cell bodies within the ganglia
What are the supporting nerve cells involved in the central nervous system?
What do they do?
- Oligodendrocytes - Same function as Schwann cells –> 1 oligodendrocyte forms myelin sheaths around many axons
- Microglia/macrophages - migrate through CNS and consume debris
- Astrocytes - Help regulate the external environment of neurons
- Ependymal cells - line ventricles or cavaties of the brain and spinal cord
Why is the astrocyte shaped the way it is?
The many foot processes is has attaches to various structures (like neurons and capillaries). This also allows for the cells to influence interactions between neurons and blood
