Week 2- Peripheral Nervous System Flashcards
How can the PNS be divided up?
Somatic and autonomic.
Sensory (afferent) carry info towards CNS
Motor (efferent) nerves carry info away from CNS
How many pairs of cranial nerves do we have?
12 (have names)
How many pairs of spinal nerves do we have?
31 (spinal nerves have a letter and number)
What do the somatic afferent and efferent nerves do?
Afferent: from skin, skeletal muscle and joints
Efferent: to skeletal muscles
What is a dermatome?
An area of skin that is supplied by a single spinal nerve
What is a myotome?
A group of muscles innervated by a single spinal nerve
What does anasthesia mean?
No sensation
How can visceral (autonomic) nerves be catagorised?
They carry info from viscera (organs)
Can be divided into…
Parasympathetic: innervate viscera only
Sympathetic: innervate viscera and periphery
What’s a ganglion?
A collection of cell bodies outside the CNS
What’s a nucleus?
A collection of cell bodies inside CNS
What’s a plexus?
A network of interconnecting nerves
Where are the cell bodies of afferent fibres found?
In the spinal ganglia
Where do visceral efferent nerves synapse?
In a peripheral ganglion
What are the bundles that peripheral nerves are arranged into?
Fasciculi
What are the layers of connective tissue of a nerve?
Epineurium: external vascular layer
Perineurium: individual fascicles covered in
Endoneurium: individual axons covered by this layer