Nervous system Flashcards
Functions Of The Nervous System
To receive information from external and internal stimuli
* To interpret and integrate information received
* To bring about necessary response
Neurons
basic functional units of the nervous system
Responsible for transmission of nerve impulses throughout nervous tissue
Neuroglial cells
supply nutrients to and carry waste material
away from neurons
Neuroglia (Glia Cells)
support to neurons.
insulation
communication
nutrient
waste transport.
Neuron Structure
Neuron body - contains nucleus
Dendrites - Carries nerve
impulses towards cell
Axon - conducts nerve
impulses away
sensory receptors respond to what stimuli
heat, cold, touch, pressure,
stretch, physical changes.
White matter
tissue containing myelinated axons
Nodes of Ranvier
Gaps in the
myelin sheath on an axon
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)
Connector or Intercalated
Neuron
Lies between a sensory neuron and a motor neuron
Motor Nerves (Efferent)
Send the impulse away from the CNS to a muscle or gland to promote an action
Visceral Fibres
A neuron that send impulses to the CNS in response to changes in organs
Somatic Fibres
Sense of touch
voluntary movement
Ganglion
Collection of cell bodies outside of the
CNS
Receptor
Sensory Nerve Ending
Effector
carries out an activity, instructed by the nervous system
SYNAPSES
Impulses passed from 1
neurone to another
NEUROMUSCULAR JUNCTION
A neuron to a muscle fibre
depolarised
neuron becomes less negative
hyperpolarised
the inside of a neuron becomes more negative
Resting potential
the imbalance of electrical charge
between the negative charge of the cell contents and positive charge of the cell membrane
Action potential
Are the nerve impulses
Neurotransmitter
chemical messenger.
transmits messages between neurons or to muscle
Nervous System is divided into ?
Central nervous system (CNS) Brain/Spinal cord
Peripheral nervous system (PNS)
Nerves running in and out of the CNS
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
