Nervous System - Lecture 1
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- What is the Central Nervous System comprised of?
- The brain and spinal cord.
- What is the Peripheral Nervous System (PNS) comprised of?
- Cranial and spinal nerves.
- What is the primary functional unit of the nervous system?
- Neurons
- What do neurons do?
- They receive impulses and send them to other cells.
- Can neurons replicate?
- No, neurons are nonmitotic - they do not replicate if irreversibly damaged.
- What are the two cells of the nervous system?
- Neurons and Neuroglia.
- What is the function of Neuroglia?
- Neuroglia provide support, nourishment and protection to the neurons.
- Can Neuroglica replicate?
- Yes, they are mitotic thus, primary tumors are found here.
- Name three characteristics of Neurons:
-
Exitability
Conductivity
Ability to influence other neurons, muscle cells & glandular cells. - What does a neuron consist of?
-
Cell body
Axon (myelinated/unmyelinated)
Dendrites - What is the function of a dendrite?
- Receives impulses.
- What is the function of an axon?
- Carries nerve impulses.
- Neuroglia are also known as ________ ________and neurons are the ________ ________.
-
Supporter cells.
Functional unit. - What are the functions of the Nervous System?
- Nerve regeneration and nerve impulse.
- Explain nerve regeneration:
- A damaged axon attempts to repair itself by sprouting more synaptic terminals however if the cell body is damaged, the neuron is done.
- Would you see regeneration in the CNS, PNS, both or neither?
- Possibly in the PNS, the CNS does not regenerate.
- What is a nerve impulse?
- The initiation of a neuronal message which also involves the generation of an action potential.
- What two ways is an action potential transmitted?
- Electrically (hops node-to-node) AND Chemically (w/neurotransmitter)
- How far does an action potential travel?
- Until it reaches its target.
- What is a synapse?
- A junction between two neurons.
- What are the essential structures of synaptic transmission?
- Presynaptic terminal, synaptic cleft and a receptor site on the postsynaptic cell.
- What are the two types of synapses?
- Electrical and chemical.
- What are the two types of Neurotransmitters?
-
Excitatory
Inhibitory - What does excitatory mean?
-
"continue"
Causes an increase in Na+ permeability, increasing the likelihood that an action potential will be generated. - What does inhibitory mean?
-
"stop"
Increase in permeability of K+ and Cl-, decreasing the likelihood that an action potential will be generated. - What does the Central Nervous System (CNS)consist of?
- The brain and the spinal cord.
- Where does the spinal cord begin and end?
- It begins at the brainstem and ends at L1-L2.
- What does an ascending tract do?
- The ascending tracts carry information from the periphery to the brain.
- What does a descending tract do?
- The descending tract carries information from the brain to the body.
- What are the two descending tracts called?
-
Pyramidal
Extrapyramidal - These, originate in the cerebral cortex:
- Upper motor neurons.
- What do the upper motor neurons influence?
- Voluntary skeletal movement.
- What if there were a lesion on the upper motor neurons?
- It could cause weakness or paralysis, disuse atrophy, hyperreflexia and increased muscle tone (spasticity).
- What do the lower motor neurons influence?
- They are the final common pathway through which descending motor tracts incluence skeletal muscle.
- Where are the lower motor neurons located?
- They are located in the anterior horn of the spinal cord.
- What if there were a lesion on the lower motor neuron?
- It would cause weakness, paralysis, atrophy, hyporeflexia and muscle flaccidity.
- What is a reflex arc?
- Involuntary response to a stimulus - EXAMPLE - touching something hot and removing your hand.
- If there is damage on the lower motor neurons, which side would this affect?
- It would affect the same side.
- What side would be affected if there was damage to the upper motor neurons?
- The opposite side would be affected.
- What are the three major parts of the brain?
-
Cerebrum
Brainstem
Cerebellum - What is the cerebrum responsible for?
- Mental functioning, language, memory, judgment...
- What is the brainstem responsible for?
- Cell bodies of cranial nerves are here, conrols respiratory, cardiac, vasomotor funtion, sneeze, cough and swallowing....
- What is the cerebellum for?
- Coordinates voluntary movement, maintains body stability (vertigo) and equilibrium.
- What are the four lobes of the Cerebrum?
- Frontal, parietal, temporal and occipital.
- What is the function of the frontal lobe?
- Intellectual function and personality, skilled movements, voluntary movement and speech.