the nervous system 2 Flashcards
What is the PNS
nerves that connect the brain and spinal cord with body’s muscles, glands, sense organs and other tissues
What is the CNS
brain and spinal cord
What does the somatic nervous system innervate
skeletal muscle`
what does the autonomic system innervate
smooth and cardiac muscle. glands, GI neurones
mechanoreceptors
respond to mechanical stimuli
propioreceptors
allow us to determine where our body is
chemoreceptors
respond to binding of chemicals to the receptor membrane
nociceptors
associated with feeling pain
How does sensory afferent input move into the spinal cord
via the dorsal root
small bumps on dorsal roots (dorsal root ganglia) contain cell bodies of afferent neurones
monosynaptic reflex
afferent fibres synapse straight onto motor neurones (for reflex arc/stretch reflex)
ascending pathways
project up into the brain
specific ones project to the somatosensory cortex
descending pathways
starts in the brain, down to the periphery
travels thorugh the raphe nuclei
types of cranial nerves
olfactory, optic, oculomotor, vagus
olfactory nerve
afferent
smell
optic nerve
afferent
carries input from receptors in the eye
oculomotor nerve
efferent
innervates skeletal muscles that move the eyeball
vagus nerve
efferent
innervates skeletal muscle
Glial cells
help neurones to perform their function
eg support, insulation, guide developing neurones, BBB, immune response
where are glial cells found
surround the cell body, axon and dendrites of neurones
types of glial cells
oligodendrocyte, astrocyte
oligodendrocyte
producess myelin in the CNS (schwann cells do this in the PNS)
What does the PNS consist of
nerves and ganglia outside the brain and spinal cord
astrocyte
takes up K+ ions and neurotransmitters, then releases them elsewhere
keeps balance and regulates extracellular fluid composition
stimulates formation of tight junctions between cells that make up walls of capillaries in the brain (forms BBB)
3 types of coverings of the CNS (between sof neural tissue and bones)
dura mater next to bones
arachnoid mater in th middle
pia mater next to nervous tissue