Assist the neuron Do not conduct an impulse 4 types in CNS 2 types in PNS

Produce CSF (Cerebral spinal fluid) Concentrated in choroid plexus

Most common Structural, Blood Brain Barrier, Regulate AP

Lecture notes Nervous system Flashcards by Chantelle Smith

What is the order of muscle conduction?

1) Motor neuron action potential
2) Synaptic knob & neuromuscular junction
3) Sarcolemma action potential
4) T-tubule action potential
5) Release of Ca++from terminal cisternae

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What are the next events after the 5 first muscle conduction events?

1 )Ca++ bonds to troponin causing shift in
tropomyosin
2) Bonding site is exposed on actin
3) Myosin head bonds to actin
4) Stored energy is released as “power stroke”
5) Actin moves relative to myosin
6 )ATP used to detach head and bend myosin back to resting position (energy loaded)
7 )Cycle repeated

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What is the structural and functional unit of the nervous system?

Neuron

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Neuroglia

Assist the neuron
Do not conduct an impulse
4 types in CNS
2 types in PNS

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Ependymal (CNS)

Produce CSF (Cerebral spinal fluid)

* Concentrated in choroid plexus

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Astrocyte (CNS)

Most common

* Structural, Blood Brain Barrier, Regulate AP

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Microglia (CNS)

For CNS Defense- think of WBC’s

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Oligodendrocyte (CNS)

Produce myelin sheath

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Neurolemmocyte (PNS)

Produce myelin sheath

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Satellite (PNS)

Separate cell bodies of ganglia and homeostasis of ganglion environment

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What are the two structural divisions of the

nervous system?

CNS and PNS

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What are the two functional divisions?

Sensory and Motor

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What is the involuntary system called?

Autonomic

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Which part of a neuron can have more than one branch coming off the cell body?

Dendrites

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What are the 3 structural neurons?

Unipolar, bipolar, multipolar

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What are the parts of a polysynaptic reflex?

RSIME

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What is the voltage for the resting potential of a neuron?

-70mv inside v outside

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What is the impulse?

Reversal of charge transferred to adjacent areas (+30mv)

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If stimulated anywhere along a neuron the impulse will travel in the dendrite to axon direction. True or False?

False! It will travel in BOTH directions

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What maintains the resting potential?

Ion pumps and diffusion

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What kind of molecules are the ion pumps?

Proteins

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Where are they located?

In the cell membrane of neurons and muscles

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A “strong enough” stimulus has to be above the _____ to cause an action potential?

Threshold

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What are the “helper” cells of the nervous

system called?

Neuroglia (glia)

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Which produces CSF?

Ependymal

Which fights disease?

Microglia

Which produces myelin sheath?

Oligodendrocytes and Neurolemmocytes

Which isolates cell bodies in the spinal ganglia?

Satellite

Myelin is

A waxy membranous wrapping that Insulates the axon

the myelinating cell of the PNS

Neurolemmocyte (Schwann Cell)

Neurilemma is the

The outermost part

Neurofibril node (Nodes of Ranvier) are

Small gaps between each myelinating cell. The axon is exposed

The myelinating cell of the CNS myelinate several axons

Oligodendrocytes

Speeds up impulses

Saltatory conduction

Two factors effect speed of conduction

1. Size of the axon | 2. Insulation with myelin sheath, Large, insulated axons are faster

Nerve is

A bundle of neuron fibers

* Fibers bundled as tracts * Cell bodies in nucleus * Myelin by oligodendrocytes

Central nervous system

* Fibers bundled as nerves * Cell bodies in ganglion * Myelin by neurolemmocytes

Peripheral Nervous System

Describe chemical synapse

*The axon ending (of the pre-synaptic neuron) has many synaptic vesicles filled with neurotransmitter (acetylcholine, serotonin, norepinephrine, dopamine, GABA) * When the action potential reaches the synaptic knob, the synaptic vesicles release their contents into the synaptic cleft * The neurotransmitters cross this synaptic cleft and bind to receptor sites on the post-synaptic neuron (2nd neuron) or effector (muscle or gland)

Why have a synapse?

Keeps impulse unidirectional

Synapse and memory

* They also play a role in memory * As signals cross a synapse the association is strengthened * This is how memories are “built"

Neurons can synapse with?

* Other neurons * Muscles * Glands

Sympathetic deals with

Fight-or-flight responses

Parasympathetic deals with

Rest-and-digest responses

Sympathetic nerves: Summary, origin, specific responses, neurotransmitter

Summary: Fight or flight Origin: Thoracolumbar Specific responses: Gland secretions decrease (saliva gets thick), GI tract inhibited, sphincters contract, pupils dilate, increased pulse rate Neurotransmitter: norepinephrine

Parasympathetic nerves: Summary, origin, specific responses, neurotransmitter

Summary: Rest-and-digest Origin: Cranial-sacral Specific responses: Gland secretions increase (saliva gets watery), GI tract stimulated, sphincters relax, pupils constrict, decreased pulse rate Neurotransmitter: acetylcholine

Autonomic includes

Subconscious pathways

* Glands are closer to CNS * Short preganglionic neurons * Long post ganglionic neurons

Sympathetic

Sympathetic trunk is

Ganglion and synapse

* Preganglion neurons arise from cranial or pelvic nerves * Ganglion are closer to organs * Long preganglion neurons and short postganglionic neurons

Parasympathetic

Primitive brain comes from

Neural tube

What germ layer does the brain from the neural tube derive from?

Ectoderm

What if it doesn’t close at the caudal end?

Spina bifida

The cephalons short version

``` Prosencephalon • Telencephalon • Diencephalon Mesencephalon Rhombencephalon • Metencephalon • Myelencephalon ```

The cephalons long version

``` Telencephalon • Cerebrum Diencephalon • Thalamus and hypothalmus Mesencephalon • Peduncles and Colliculi Metencephalon • Pons and Cerebellum Myelencephalon • Medulla oblongata ```

For the brain, Gray is located on

Outside

Gray is

Cell bodies & unmyelinated axons

White is

Myelinated axons..

Funiculus is the spinal cord is

White matter

What is the communication between left and right hemispheres in the brain?

Corpus callosum |

How much energy does the brain use?

The human brain takes up 2% of human body weight but uses 20% of its energy

Olfactory is

* Odor detection | * Sensory

Optic

Sight-Sensory

Oculomotor, Trochlear & abducens

To the eye. eye muscles

Trigeminal

* Three branches * Face-sensory * Chewing-motor

Facial

* Motor to face | * Sensory from tongue

Vestibulocochlear

* Hearing and balance | * Sensory

Glossophparyngeal

* Tongue sensory | * Throat-motor

Vagus

* Visceral- sensory | * Throat- motor

Accessory

* Neck and upper back | * Motor

Hypoglossal

Tongue-Motor

What happens when a neuro damaged?

* Depends on the damage * If cell body is damaged the neuron is lost and is not replaced * If axon is in PNS it may repair * If axon is in CNS usually no repair * Depends upon the neurolemma

Why is there no repair to the CNS neurons?

Repair within the CNS is limited due to several factors. * Oligodendrocytes do not release a nerve growth factor * The large number of axons crowded within the CNS tend to complicate regrowth activities * Astrocytes & connective tissue coverings may form some scar tissue that obstructs axon regrowth