nervous system Flashcards
what is in the central nervous system
brain and spinal chord
what is in the peripheral nervous system
all the other nerves tissues not in the CNS
spinal nerves - 31 pairs connect with spinal chord
cranial nerves - 12 pairs connect with brain
autonomic nerves - organs, smooth muscles, glands, visceral afferents, sympathetic nerves, parasympathetic nerves
what functions allow a single nerve fibre (axon) to conduct action potentials
- somatic sensory function
(tells spinal cord/brain about pain on body wall) - somatic motor function
(tells skeletal muscle to contract) - special sensory function
(tells brain about special sensation- taste, smell, sight, sounds, balance) - visceral afferent function
(tells spinal cord/brain about pain from organ) - sympathetic function
(tells cardiac/smooth muscle to contract or gland to secrete) - parasympathetic function
(tells cardiac/smooth muscle to contract or gland to secrete)
what can a mixed nerve do
it can carry 2 or more functional types of nerve fibre to any given region of the body or structure
what does the outermost layer of the cerebral hemisphere contain
cerebral neocortex
gyri and sulci
what are the 4 lobes of the cerebral hemisphere and what do they do
occipital - back - visual processing
parietal - top - proprioception, sensory information integration
temporal - side - visual memory, processing sensory input
frontal - front - motor function,
impulse control, judgement
what does the cerebellum control
fine motor control, balance, posture, coordination)
describe the appearance of the axial section of the brain
grey matter - outermost layer - full of cell bodies
white matter - deep, contains many axons which are myelinated (whiter appearance)
where is the grey and white matter in the spinal cord
white matter is superficial and grey matter is deep
what are the cranial nerves 1-4
CN I - olfactory nerve
CN II - optic nerve
CN III - oculomotor nerve
CN IV - trochlear nerve
what are the cranial nerves 5-8
CN V - trigeminal nerve
CN VI - abducent nerve
CN VII - facial nerve
CN VIII - vestibulocochlear nerve
what are cranial nerves 9 - 12
CN IX - glossophryngeal nerve
CN X - vagus nerve
CN XI - spinal accessory nerve
CN XII - hypoglossal nerve
how are the cranial nerves numbered and named
order from anterior to posterior
according to functions or anatomy
what are the functions of the cranial nerves
special sensory - I,II, VIII
somatic motor - IV, VI, XI, XII
mixed - III, V, VII, IX, X
Describe the appearance of the floor of the cranial cavity
anterior cranial fossa
middle cranial fossa
posterior cranial fossa
why are there canals in the base of the skull
for CNs to pass between the brain and periphery
where does the spinal cord go through
- connects to brain, passes through foramen magnum
- connects bilaterally with spinal nerves (31 pairs)
- ends inferiorly at L1/L2 intervertebral disc level (conus medullaris)
what protects the spinal cord
vertebral canal
what are the 4 segments of the spinal cord
cervical, thoracic, lumbar, sacral/coccygeal
what are the 2 enlargements in the spinal cord
cervical and lumbosacral
what is longer, the adult vertebral column or the adult spinal cord
vertebral column
where do the lumbar and sacral spinal nerve roots go
they descend in vertebral canal to their respective intervertebral foraminae - cauda equina
how does the spinal cord connect to spinal nerves
bilaterally
what are the spinal nerves
8 pairs of cervical spinal nerves
c1 - c8
12 pairs of thoracic spinal nerves
T1-T12
5 pairs of lumbar spinal nerves
L1-L5
5 pairs of sacral spinal nerves
S1-S5
1 pair of coccygeal spinal nerves
co
what is a dermatome
area of skin supplied by both the anterior and posterior rami of spinal nerves
what is the T4 dermatome
what is the T10 dermatome
male nipple
umbilicus
what environment are the somatic and autonomic nervous system
somatic nervous system - external environment VOLUNTARY
autonomic nervous system - internal environment INVOLUNTARY
what do somatic neurons supply
the soma - body wall
what is the role of the somatic nervous system
senses and responds to the external environment
Where are the axons of the somatic neurons found
in spinal nerve branches e.g intercostal nerves, phrenic nerves
what are the 2 nerve fibres in teh somatic nervous system
somatic sensory nerve fibres - from skin, parietal pleura, skeletal muscles, bones and joints
somatic motor nerve fibres - to skeletal muscles
what is the role of the autonomic nervous system
sense and responds to internal environment (heart rate, blood pressure, digestion, glandular secretions)
what are the 2 parts of the autonomic nervous system
sympathetic - fight or flight
parasympathetic -rest and digest
describe what happens during the sympathetic part of ANS, fight or flight
heart rate increases
arterioles dilate or constrict
skin makes hair stand up
lungs dilate bronchioles
gut reduces motility/closes sphincters
pupils dilate
liver releases glucose
describe what happens during the parasympathetic part of ANS, rest and digest
supplies the same organs except except skin and arterioles
opposes sympathetic system
where do sympathetics originate from and where do they go
autonomic centres of the brain, passes down spinal cord, exits spinal cord with T1-L2 spinal nerves - thoracolumbar outflow
travels to sympathetic chains running the length of vertebral column, passes into all spinal nerves to supply sweat glands, arrector ,muscles, arterioles, passes into splanchnic nerves to supply organs
