Nervous system II Flashcards
how many cranial and spinal nerves does the PNS have?
- 31 pairs of spinal nerves
- 12 pairs of cranial nerves
what is a afferent nerve?
- sensory nerve which conveys impulses from sensory organs to the brain
what is an efferent nerve?
- motor nerve which conveys impulses from the brain through the spinal cord to the effector organs
what is the epineurium?
epineurium is a tissue which surrounds and encloses a number of bundle of nerve fibres
what is the perineurium?
perineurium is a smooth tissue surrounding each bundle of fibres
what is the endoneurium?
endoneurium is a delicate tissue which surrounds each individual fibre which is continuous with the septa that passes inwards from perineurium
what are most large nerves covered in?
epineurium
what are some nerves which are formed by sensory and motor nerves (mixed nerves)
- cervical nerves
- thoracic nerves
- lumbar nerves
- sacral nerves
- coccygeal nerves
how do mixed nerves work in the spinal cord?
- sensory and motor nerves are separate
- outwith spinal cord they may run within the same tube of CT, then termed mixed nerves
what are some spinal cord sensory nerves?
- olfactory nerve
- optic nerve
- V111 vestibulocochlear nerve
what are some spinal cord motor nerves?
- 1V trochlear nerve
- V1 abducent nerve
what are some spinal cord mixed nerves?
- trigeminal nerve
- V11 facial nerve
what are some cranial mixed nerves?
- 1x glossopharyngeal nerve
- vagus
what are some cranial motor nerves?
- 1x accessory nerve
- 11x hypoglossal nerve
when is the sympathetic nervous system active?
during stress
