Nervous System Flashcards
What are the components of the CNS?
The brain
spinal cord
central controller
What are the components of the peripheral nervous system?
spinal nerves (connect with the spinal cord) cranial nerves (connect with brain) Autonomic nerves (parasympathetic, sympathetic & visceral afferents)
What is a collection of nerve cell bodies?
a ganglion in PNS
What relationship must bundles of nerve fibres, axons, wrapped in connective tissue have?
they must all be of the same modality
or
are mixed somatic motor, somatic sensory and sympathetic (5 of the cranial nerves are mixed)
What is the direction of the action within the motor (efferent) nerve?
towards the body wall or body cavity or organ
What is the direction of the action within the sensory (afferent) nerve?
Action potential towards brain
What is the outer layer of the cerebral hemispheres?
the cortex - it consists of gyri (hills) and sulci (grooves)
How many pairs of cranial nerves are there?
12 - there are no sympathetic axons in cranial nerves
What is the accronam for remembering the functions of the cranial nerves?
Some Say Marry Money But My Brother Says Big Brains Matter More
What is the name of the CN I?
olfactory nerve
What is the name of the CN II?
optic nerve
What is the name of the CN III?
oculomotor nerve
What is the name of the CN IV?
trochlear nerve
What is the name of the CN V?
trigeminal nerve
What is the name of the CN VI?
abducent nerve
What is the name of the CN VII?
facial nerve
What is the name of the CN VIII?
vestibulocochlear nerve
What is the name of the CN IX?
glossopharyngeal nerve
What is the name of the CN X?
vagus nerve
What is the name of the CN XI?
spinal accessory nerve
What is the name of the CN XII?
hypoglossal nerve
How do the cranial nerves get in and out of the brain?
through foraminae/ fissures - which are little holes in the base of the skull for the CNs to go through
Where does the spinal cord pass through?
the foramen magnum
it is protected by the vertebral canal
What are the 4 segments of the spinal cord?
cervical
thoracic
lumbar
sacral/coccygeal
What are the 2 enlargements of the spine?
the cervical and lumbosacral
Where does the spinal cord end?
inferiorly at L1/L2 intervertebral disc level
What is the short hand for the vertebrae?
C1 - C7 (7 Cervical) T1 - T12 (Thoracic) L1 - L5 (Lumbar) S1 - S5 (Sacral) Co (coccygeal)
How many vertebrae are there?
7 cervical 12 thoracic 5 lumbar 5 sacral fused to form 1 sacrum but still have sacral foraminae 4 coccygeal fused to form 1 coccyx
How are the spinal nerves named?
- in the cervical region it is according to the vertebrae below it
- the rest of the spinal nerves are names according to the vertebrae above it
What do spinal nerves supply?
The body wall (soma), they are completely contained within the intervertebral foramina
each pair of spinal nerves supplies one ‘strip’ of the soma
Where do the spinal nerves connect from the intervertebral foramina?
- soma structures via rami
- spinal cord via roots and rootlets
What do the posterior rami supply?
small posterior strip
What do the anterior rami supply?
- the remainder of the posterior part, the lateral and the anterior parts of the strips
- all of the limbs
via plexus
What is a dermatome?
an area (strip) of skin supplied by both the anterior and posterior rami of a spinal nerve (except in limbs they have no posterior rami)
What is the T4 dermatome?
At the nipple
What is the T10 dermatome?
umbilicus
Where is the cervical plexus?
C1-C4 anterior rami supplies the posterior scalp, neck wall and the diaphragm
Where is the brachial plexus?
C5-T1 anterior rami supples the upper limb
Where is the lumbar plexus?
L1-L4 anterior rami
Supplies lower limb
Where is the sacral plexus?
L5-S4 anterior rami supplies the lower limb, gluteal region and perineum
What does the somatic nervous system include?
the soma (body wall) external environment
What structures are innervated by the somatic nervous system?
skin fascia skeletal muscle skeleton internal lining of body cavities
What does the autonomic nervous system include?
The visceral motor system
internal environment
What structures are supplied by the ANS?
viscera
glands
smooth and cardiac muscle
external lining of organs
Where is the ANS located?
- internal organs in body cavities, chest pelvic and abdominal cavity
- body wall organs sweat glands, smooth muscles and arterioles
What receptors sense touch, temperature and pain respectively?
mechanoreceptors
thermoreceptors
nociceptors
What is a spinal reflex?
When the impulse misses out pathway to the brain it is an involuntary protective response
What are visceral afferent nerves?
They are the organs sensory nerves ANS
Where do sympathetic nerves exit the spinal cord?
T1-L2
symapthetic nerves often hitch a ride with arteries to the all head neck organs and skin
- via splanchnic nerves to reach organs
What is a lateral horn to the vertebral column?
it is for the cell bodies of the next sympathetic neurones in the chain
How do the parasympathetic axons leave the CNS?
CN III, VII, IX & X & sacral spinal nerves
What does the vagus nerve supply?
organs of the neck, chest and abdomen as far as the mid-gut
How do the parasympathetic nerve travel to the hindgut, pelvis and perinum?
carried by the sacral spinal nerves
