The Nervous System 1 Flashcards
What are the divisions of the PNS?
Somatic nervous system
Autonomic nervous system
What does the autonomic nervous system break down into?
Sympathetic and Parasympathetic
What is an afferent neurone?
Sensory
Arrive - bring signals towards the CNS
What is an efferent neurone?
Motor
Project away from the CNS - Exit
What does the somatic nervous system consist of?
Spinal nerves
Cranial nerves
What does somatic and visceral mean?
Somatic - body wall
Visceral - organs themselves and body wall organs
What would the autonomic nervous system supply?
Enteral environment
- organs
heart, glands, smooth and cardiac muscle, external lining of lungs
What would the somatic nervous system supply?
The external environment
Skin, fascia, skeletal muscle, skeleton, internal lining of body cavities
What is the large hole in the back of the skull that the spinal cord goes through?
Foramen magnum
What are the 3 different sections of the floor of the cranial cavity?
Anterior, middle and posterior cranial fossa
What are the 3 parts of the brainstem from superior to inferior?
Midbrain
Pons
Medulla oblongata
What are the 4 segments of the spinal cord?
Cervical - enlargement for limb
Thoracic
Lumbar - enlargement for limb
Sacral/coccygeal
How many spinal nerves are there?
31 pairs
When does the spinal cord end?
At the conus medullar is at L1/L2
What is the outer and inner area made out of in the brain?
Outer - grey matter - cell bodies
Inner - white matter - many axons which are myelinated
What is the outer and inner area made out of in the brain stem?
Outer - white matter
Inner - grey matter
Which cranial nerves contain special sensory?
CN 1 olfactory , CN 2 optic, CN 8 vestibulocochlear
What is the plate of the ethmoid bone called?
Cribriform plate
Describe the rootlets of the ventral grey horn/anterior part of the spinal…?
Anterior rootlets are motor
Describe the rootlets of the dorsal grey horn/postior part of the spinal…?
Posterior rootlets are sensory
What do the rootlets and roots come together to form?
Spinal nerve, mixed
What then comes off the spinal nerve?
Posterior rami - mixed
Anterior rami - mixed
Where are spinal nerves located ONLY?
Within the intervertebral foramina
How many spinal nerves do we have for each section of the spinal column?
8 (C1-C8(C8 spinal nerve exits between C7 and T1 vertebrae )) Cervical spinal nerves 12 (T1-T12) Thoracic spinal nerves 5 (L1-L5) Lumbar spinal nerves 5 (S1-S5) Sacral spinal nerves 1 (Co1) Coccygeal spinal nerve
31 spinal nerves
How many spinal vertebrae do we have in each section?
7 Cervical vertebrae
(C1-C7)
12 Thoracic vertebrae
(T1-T12)
5 Lumbar vertebrae
(L1-L5)
Sacral (5 fused vertebrae)
Coccyx (4 fused vertebrae)
33 vertebrae
What do the posterior rami supply?
The posterior paramedic strip of each segment
What do the anterior rami supply?
The remained of the posterior part of the segment and the lateral and anterior parts of the segments
How do the rami supply all of the limbs?
Via plexus (anterior rami)
What are nerve plexuses?
They are networks of intertwined anterior rami
What plexuses do you get?
Cervical plexus - C1-C4
Brachial plexus - C5-T1
Lumbar plexus - L1-L4
Sacral plexus - L5-S4
Where do the sympathetic nerves exit the spinal cord?
T1-L2 - they travel to sympathetic chains running the length of the vertebral column
Pass into both anterior and posterior rami ‘hitch a ride’
What do the splanchnic nerves supply?
Organs
What do the lateral horns of the spinal cord contain?
Sympathetic fibres - only T1-L2
Where does the sympathetic axon leave the spinal cord?
In the anterior root/rootlets
How do parasympathetics leave the CNS?
Via cranial nerves 3,7,9 and 10 and the sacral spinal nerves
Craniosacral outflow
What do the parasympathetics supply?
Internal organs, not the body wall.
how would you describe parasympathetic outflow?
Craniosacral outflow
How would you describer sympathetic outflow?
Thoracolumbar outflow
