Anatomy nerves Flashcards
The divisions of the nervous system
Structurally- central nervous system and peripheral nervous system
Functionally- Somatic nervous system and the autonomic nervous system.
What makes up the CNS
Brain and spinal cord
What is a nucleus?
A collection of nerve cell bodies in the CNS
What is a ganglion?
A collection of nerve cell bodies in the PNS
What do afferent (sensory fibres) convey
Impulses from organs to the CNS
What do efferent (motor fibres) convey
Impulses from the CNS to the effector organs
Nerves are either:
Cranial nerves, spinal nerves or derivatives of these
Where do spinal nerves arise?
They arise in bilateral pairs from areas of the spinal cord (e.g. T4 nerve) through intervertebral formina
How many pairs of spinal nerves are there?
31
Describe the path of the spinal nerves out of the spinal cord.
They arise from the grey matter (cell bodies) and go down rootlets to either the anterior root (motor) or posterior root (sensory). These roots then join and the nerve fibres mix together. They then split to form a posterior ramus and anterior ramus which consists of both sensory and motor neurones.
Dermatome
Unilateral area of the skin supplied by each spinal nerve.
Where does the posterior rami of spinal nerves supply?
Synovial joints of the vertebral column
Deep muscles of the back and the skin lying above this
Where does the anterior rami of the spinal nerves supply?
Upper and lower limbs
Anterior and lateral areas of the trunk
Muscles and skin
Types of fibres in the cranial and spinal nerves
General sensory fibres (somatic)
Somatic motor fibers
Visceral sensory fibers
Visceral motor fibers
Describe what each of the types of fibres do
General sensory fibres- transmit sensations from the body to the CNS
Somatic motor fibres- transmit impulses to skeletal muscle
Visceral sensory fibres- transmit pain or subconscious visceral reflex sensations from organs and blood vessels to the CNS
Visceral motor fibres- transmit impulses to smooth muscle and glandular tissues
