A&P - Chapter 21 (Part 1) Flashcards
What are the 2 main division of the nervous system?
- Central NS
2. Peripheral NS
Where do peripheral nerves extend to?
To the peripheral parts of the body
What does the peripheral nervous system communicate between?
The CNS and the rest of the body
How many cranial nerve pairs do we have?
12 pairs
How many spinal nerve pairs do we have?
31 pairs
What do spinal nerves conduct?
Impulses between the spinal cord and the other parts of the body not supplied by the cranial nerves
- all parts of the body except the head
What do spinal nerves contain? (2)
- Sensory fibres
2. Motor fibres
What impulses do the spinal nerves conduct that are necessary? (2)
- Sensation movements
2. Voluntary movements
Where do spinal neves exit from?
The spinal cord
What do spinal nerves branch to form?
The many peripheral nerves of the body’s trunk and limbs
Where do nerves exit throughout the spinal cord?
Superior to its numbered vertebra
-eg) C1, T8, L3
Where do thoracic spinal nerves exit?
Horizontally through the intervertebral foramina
Where does the lumbar, sacral and coccygeal nerve roots descend from?
Point of origin to the lower end of the spinal cord (level of the first lumbar vertebra) before reaching the intervertebral foramina of the respective vertebra
- through which the nerves emerge
What does cauda equina describe?
The appearance of the lower end of the spinal cord and its spinal nerves as a horses tail
How do the spinal nerves attach to the spinal cord?
Via 2 roots
What are the 2 roots for the spinal nerves?
- Dorsal root
2. Ventral root
Where is the dorsal root located?
Posteriorly
Where is the ventral root located?
Anteriorly
What does the dorsal root contain? (2)
- Sensory neurons
2. Dorsal root ganglia
What does the ventral root contain? (2)
- Somatic motor fibres
- voluntary - Autonomic motor fibres
- involuntary
Where do ventral motor fibres arise from?
The anterior lateral horn
What are 2 terms related to the spinal nerves?
- Ramus
2. Plexus
Ramus
One of the several large branches formed after each spinal nerve emerges from the spina cavity
What dorsal ramus is more complexed?
Ventral
Plexus
Complex network formed by the ventral rami of most spinal nerves
What 2 spinal nerves dont contribute to plexus?
- T2
2. T12
What do plexus form after they are subdivided?
Join to form a single peripheral nerve
What do plexus contain?
All the fibres that innervate a particular region of the body
