The organisation of the nervous system Flashcards
what is the nervous system?
a system that allows the organism to:
- sense info about its environment
- to respond rapidly and accordingly
what does the somatic sensory neuron detect?
- touch
- pain
- pressure
- vibration
- temperature
- hearing
- equilibrium
- vision
- smell
what does the visceral sensory neuron detect?
- stretch
- pain
- temperature
- chemical changes
- nausea
- hunger
- taste
- irritation
what neurons makes up the sensory afferent division.
the somatic and visceral sensory neurons
what makes up the central nervous system?
the cranial and spinal nerves
what does the somatic motor do?
-innervates skeletal muscles for movement
what does the visceral motor do?
-innervates smooth muscles, cardiac muscles and glands. aka autonomic nervous system (ANS)
what are the 2 ANS divisions?
parasympathetic and sympathetic divisions
what are the 2 principal cell types of the nervous system?
neurons (transmit electrical signal) and neuroglia (support cells)
6 classes of neuroglia?
- Astrocytes
- Microglia
- Oligodendrocytes
- Schwann cells
- Non ciliated ependymal cells:
- Ciliated ependymal cells
what does the astrocyte do?
form the blood brain barrier.
what does the microglia do?
phagocytosis to fight infection
what does the oligodendrocytes do?
bind the CNS neurons together and insulate the axons.
what does the schwann cells do?
myelin sheath
what does the non-ciliated ependymal cells do?
secrete cerebro spinal fluid.
what does the ciliated ependymal cells do?
move cerebro spinal fluid around to keep it homogenous
what is white matter?
-bundles of axons each coated with a myelin sheath
what is gray matter?
-masses of cell bodies and dendrites each covered with synapses
what does the brain and spinal cord consist of?
gray and white matter
what is the reflex arc?
- stimulus activates receptor
- this activates the sensory neuron and transmits signal to cns
- cns processes info and transmits signal to motor neuron
- motor neuron sends signal to muscles/glands for a response
- RESPONSE!!!
what do the proprioceptive senses do?
-detect stretch in tendons, muscles, joints and ligaments
where are visceral senses more common?
- digestive and urinary tract
- reproductive organs
what are the peripheral sensory receptors?
- Exteroceptors
- Enteroceptors
- Proprioceptors
what do enteroceptors do?
detect stimuli from within i.e. the internal viscera
what do exteroceptors do?
detect stimuli from outside the body
how many pairs of cranial nerves?
12
where do cranial nerves serve?
head and neck
which two cranial nerves don’t arise from the brain stem and pass through the foramina in the base of the skull.
cranial nerves 1 and 2
which 3 cranial nerves are purely sensory, whilst the other 9 are mixed sensory and motor nerves?
- optic (2)
- olfactory (1)
- vestibulocochlear (8)
what is cranial nerve 1 and what does it do?
olfactory - for smell (info from nose) -sensory
what is cranial nerve 2 and what does it do?
optic - visual (info from eyes) - sensory
what is cranial nerve 3 and what does it do?
oculomotor - eye movement, pupil constriction and lens shape - motor
what is cranial nerve 4 and what does it do?
trochlear - eye movement - motor
what is cranial nerve 5 and what does it do?
trigeminal - info from face, mouth; for chewing - mixed
what is cranial nerve 6 and what does it do?
abducens - eye movement - motor
what is cranial nerve 7 and what does it do?
facial - for taste, tear, expressions and salivary gland secretions - mixed
what is cranial nerve 8 and what does it do?
vestibulocochlear - hearing and equilibrium - sensory
what is cranial nerve 9 and what does it do?
glossopharyngeal - info from oral cavity; baro and chemoreceptors in blood vessels. For swallowing, salivary gland secretions - mixed
what is cranial nerve 10 and what does it do?
vagus - info from and to sensory and efferents - mixed
what is cranial nerve 11 and what does it do?
spinal accessory - oral cavity, neck and shoulder muscles movement - motor
what is cranial nerve 12 and what does it do?
hypoglossal - tongue muscles - motor
what is the cauda equina?
the collection of nerve roots at the inferior end of the vertebral canal of the spine
what protects your spinal chord?
your vertebrae
how many pairs of spinal nerves and how do they attach?
- 31 pairs
- attach through dorsal and ventral nerve roots
what 2 nervous systems is the peripheral nervous system divided into?
- autonomic nervous system
- somatic nervous system
what is the role of the autonomic nervous system?
Involuntary smooth muscle contractions
what is the role of somatic nervous system?
Voluntary skeletal muscle contraction based on motor neurons at the neuromuscular junction
what is the difference between the sympathetic and parasympathetic system?
neurotransmitters used in preganglionic and postganglionic:
- sympathetic = Ach and NorAdrenaline
- parasympathetic = Ach and Ach
what are the only 2 exceptions to the sympathetic nervous system postganglionic fibre that doesn’t release NA?
- the transmission of a signal to sweat glands releases ACh not NA
- transmission of a signal to the adrenal glands releases adrenaline not NA
what is used to break down acetylcholine in the synapse to only result in one signal and not multiple ones?
acetylcholinesterase
