Nervous system Flashcards by Abi Clark

Functions Of The Nervous System

To receive information from external and internal stimuli
* To interpret and integrate information received
* To bring about necessary response

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Neurons

basic functional units of the nervous system

Responsible for transmission of nerve impulses throughout nervous tissue

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Neuroglial cells

supply nutrients to and carry waste material
away from neurons

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Neuroglia (Glia Cells)

support to neurons.
insulation
communication
nutrient
waste transport.

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Neuron Structure

Neuron body - contains nucleus
Dendrites - Carries nerve
impulses towards cell
Axon - conducts nerve
impulses away

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sensory receptors respond to what stimuli

heat, cold, touch, pressure,
stretch, physical changes.

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White matter

tissue containing myelinated axons

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Nodes of Ranvier

Gaps in the
myelin sheath on an axon

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where are Sensory Nerves (Afferent) found?

Found in the skin, muscles,
bones, internal organs and part of a specialised sense organ (in the eye or ear)

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Connector or Intercalated
Neuron

Lies between a sensory neuron and a motor neuron

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Motor Nerves (Efferent)

Send the impulse away from the CNS to a muscle or gland to promote an action

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Visceral Fibres

A neuron that send impulses to the CNS in response to changes in organs

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Somatic Fibres

Sense of touch
voluntary movement

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Ganglion

Collection of cell bodies outside of the
CNS

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Receptor

Sensory Nerve Ending

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Effector

carries out an activity, instructed by the nervous system

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SYNAPSES

Impulses passed from 1
neurone to another

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NEUROMUSCULAR JUNCTION

A neuron to a muscle fibre

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depolarised

neuron becomes less negative

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hyperpolarised

the inside of a neuron becomes more negative

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Resting potential

the imbalance of electrical charge
between the negative charge of the cell contents and positive charge of the cell membrane

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Action potential

Are the nerve impulses

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Neurotransmitter

chemical messenger.
transmits messages between neurons or to muscle

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Nervous System is divided into ?

Central nervous system (CNS) Brain/Spinal cord

Peripheral nervous system (PNS)
Nerves running in and out of the CNS

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Grey matter

cell bodies with little or no myelin

Brain functions

Controls and co-ordinates all the body’s normal activities

glia cells

support and protect the neurons

sections of the brain

Forebrain -Cerebrum/Thalamus/ Hypothalamus Midbrain Hindbrain -Medulla oblongata, Pons & Cerebellum

What is the function of the corpus callosum

To maintain a flow of information between the two halves of the cerebrum

Gyri -

folds in cerebral hemispheres

Sulci

shallow grooves separating the gyri

Fissures

deep grooves separating the gyr

* Longitudinal fissure -

prominent groove that divides the cerebrum into right and left cerebral hemispheres

Cerebrum 4 lobes

* Frontal * Parietal * Occipital * Temporal

Forebrain Thalamus

Processes information from sense organs

Forebrain -Hypothalamus

Links endocrine and nervous systems Homeostasis

Optic Chiasma

Where the optic nerve crosses

Midbrain

Passes impulses between the hind and the forebrain

Hindbrain - Cerebellum

Fine tuning voluntary movement

Hindbrain - Pons and Medulla

Pons = Sends messages through brain. *Important in respiration* Medulla Oblongata = Involuntary Actions.

Cranium

Boney shell protecting the brain

Ventricular system in the brain

Canals/cavities and ventricles inside the brain and spinal cord Filled with CSF

Cerebrospinal Fluid (CSF)

Circulates between layers of the meninges & ventricles Protection

Cerebrospinal fluid appearance

similar to plasma

Meninges layers starting from skull

Dura mater Arachnoid mater Pia mater

Blood-brain Barrier

Neuroglial cells surround blood capillaries in the brain Forming an almost impermeable layer

Where does the the spinal start and end

Medulla oblongata to Lumbar 6-7

Cauda Equina

where spinal nerves split at L6-7

Somatic Nervous System

voluntary part of the nervous system that coordinates a body’s movements

Cranial nerves leave

the brain

Spinal nerves leave

the spinal cord

Cranial Nerves

12 pairs of nerves leaving brain Sensory/Motor/mixed

Olfactory nerve = sense of smell (roman numeral)

I (1)

Optic nerve = sight (roman numeral)

II (2)

Vestibulocochlear = hearing and balance (roman numeral)

VIII (8)

Oculomotor (roman numeral)

III (3)

Trochlear nerve (roman numeral)

IV (4)

Abducens (roman numeral)

VI (6)

Facial: muscles of facial expression (roman numeral)

VII (7)

Accessory: muscles of neck and shoulder(roman numeral)

XI (11)

Hypoglossal: muscles of tongue(roman numeral)

XII (12)

Trigeminal (roman numeral)

V (5)

Glossopharyngeal (roman numeral)

IX (9)

Vagus (roman numeral)

X (10)

Spinal nerves Dorsal root

Carries sensory fibres from the body towards the spinal cord

Spinal nerves Ventral root

Carries motor fibres away from the spinal cord towards organs.

Autonomic Nervous System

autonomic nervous system is the involuntary part of the nervous system (homeostasis)

Involuntary nerves

Sympathetic - prepares the body for action (fight or flight) * Parasympathetic - generally has a more calming effect (rest and digest)

what system is responsible for the ‘Fright, Flight And Fight’ response

Sympathetic nervous system

Reflex Arc

Protective mechanism causing a rapid response to potentially dangerous stimuli

Monosynaptic or simple arch reflexes

These involve 1 synapse in the pathway – e.g. patella reflex

Polysynaptic or complex arch reflex

Involving at least 1 intercalated neuron and synapses in the pathway – e.g. withdrawal reflex

Common Reflexes Tested

* Pedal * Panniculus * Palpebral * Pupillary light * Patella * Anal

Peripheral Nerve Pathways Of The Forelimb

Brachial plexus Radial Nerve Median Nerve Ulnar nerve

Peripheral Nerve Pathways Of The Hindlimb

lumbosacral plexus Sciatic Nerve Femoral Nerve Phrenic Nerve

CNS glial cells

Ependymal Oligodendrocytes Astrocytes Microglia

Peripheral cells

Satellite Schwann