Organisation Of The Nervous System Flashcards
Describe the basic organisation of the Nervous System
CNS: brain and spinal cord
PNS:
Somatic: voluntary control, sensory intro from skin and motor output in skeletal muscle
Autonomic/visceral: involuntary, regulates function of viscera - parasympathetic and sympathetic arms
Describe the discreet anatomy of the ANS?
Sympathetic: FIGHT OR FLIGHT, nerves from spinal cord
Parasympathetic: REST AND DIGEST, nerves from sacral and coccygeal parts of spine and brain stem.
Difference between afferent and efferent?
Afferent is sensory info towards brain
Efferent is motor output towards effectors
Gross brain anatomy consists of:
Frontal lobe: ends at central gyrus, it controls personality memory and decision making
Parietal lobe: contains somatosensory cortex which processes intro like pain and touch
Occipital lobe: vision
Temporal lobe: auditory perception, amygdala sits here
Cerebellum: fine motor skills
What are the Cranial Nerves?
Control Head and Neck: I) olfactory II) optic III) oculomotor IV) trochlear V) trigeminal VI) abducens VII) facial VIII) vestibulocochlear IX) glossopharyngeal X) vagus XI) (Spinal) accessory XII) hypoglossal
ooh, ooh, ooh to touch and feel very good velvet. Such heaven.
what are the membraneous layers surrounding the brain?
Dura Mater, outer and inner
Arachnoid
(subarachnoid space)
Pia Mater
these layers are very tough and vascularised hence can cause a haematoma if they burst.
what is the difference between grey and white matter?
grey matter contains cell bodies
white matter contains myelinated axons
anatomy of the spinal cord
dorsal horn gives rise to dorsal root then dorsal root ganglion (afferent)
ventral horn gives ride to ventral root (efferent)
DAVE
what are mixed spinal nerves?
they contain afferents and efferents axons.
neurones are surrounded by endoneurium and bundles form initial nerves, each of these nerves are packed into a larger nerve called a fascicle surrounding this is the perineurium surrounding the bundle of fascicles and blood vessels is the epineurium.
function of neuroglia
packing
astrocytes maintain BBB and recycle neurotransmitter, shuttle from blood to synapses.
microglia are immune cells
oligodendrocytes produce myelin sheath in CNS
what is the regenerative capacity of axons in the PNS?
THEY CAN after injury.
injury leads to phagocyte stimulation which removes growth inhibitory debris
BUT may be compromised by aberrant axon sprouting and non specific target innervation leading to neuropathic pain.
regenerative capacity of axons in CNS?
Glia exert inhibits regeneration and forms glial scar tissue when axons in the CNS are lost.
there are no guidance pathways or systems stimulating axon growth.
Sensory information gets to the brain via two pathways
- Dorsal column-medial lemniscus Pathway,
for fine touch, vibration and determining two points - Spinothalamic Pathway,
for pain and temperature perception
THEY ARE BOTH CONTRALATERAL (swap sides at the brain)
describe the dorsal column-medial lemniscus pathway
impulse via dorsal root to dorsal column to the medulla oblongata in two bundles and form synapses at the cuneate (upper half of body) and gracile (lower half) nuclei. Here it switches sides and moves up into the brain via a synapse at the thalamus (ventral posterolateral nucleus) to the somatosensory cortex.
describe the spinothalamic pathway
impulses via the dorsal root cross onto the spinal cord immediately to the spinothalamic tract passing straight through the medulla and midbrain to the thalamus where it synapses in the Ventral Posterolateral Nucleus with another neurone which takes the impulse to the primary somatosensory cortex.
