The Organisation of the Nervous System Flashcards
Features of neurons
Made of white matter (axons) and grey matter *cell bodies)
Message travels from dendrite to synapse
What are the three types of glia and what are their functions?
Oligodendrocytes (CNS)/Schwann cells (PNS)- produce myelin to facilitate transmission
Astrocytes- enable homeostasis, physical barrier/ connector
Microglia- immune cells of the brain, phagocytose dead cells and debris
What is the nervous system?
Made up of different functional nervous systems
Electrical and chemical communication occurs throughout the body
What is the PNS made up of?
Autonomic neurons- sympathetic, parasympathetic, enteric
Motor neurons- spinal cord to muscles
Sensory neurons- sensory units to spinal cord
Describe the brain’s blood supply
Blood flows to the brain via the internal carotid and Vertebral arteries join to form the circle of wilis around the optic chiams, smaller arteries then branch off and run over the surface of the brain before penetrating into the brain itself to supply deeper structures.
The grey patter in particular has a high capillary density,
15 % of cardiac output is required for the brain. VERY sensitive to ischaemia and blockage of blood flow – stroke!
What are the four main functions of CSF?
Buoyancy- brain doesn’t feel as heavy as it is
Protection
Chemical stability- stable ionic environment
Prevention of brain ischaemia
What are the three meninges and what do they cover?
Meninges cover brain and spinal cord
Dura mater- tough connective tissue
Arachnoid membrane
Pia mater- attached to the surface of the brain and spinal cord
Narrow space between pia and arachnoid is the csf
Describe the blood brain barrier
Endothelial cells line the capillary walls with tight junctions between them
Processes from astrocytes form a barrier around blood vessels, preventing large molecules entering from blood stream
Specific transporters allow certain molecules to access the brain
The BBB is not complete in some brain areas
What are the four lobes of the brain and their main functions?
Frontal- reasoning, planning, speech, movement, problem solving
Parietal- movement, orientation recognition, stimuli perception
Occipital- visual processing
Temporal- perceptions and recognition of auditory stimuli
Describe the organisation of the spinal cord
Ventral horn at front, dorsal at the back
Two dorsal horns and two ventral horns, each have posterior and anterior
Fibres of the ventral horn form the peripheral nerve trunks that innervate organs and muscles
Sensory information enters via the dorsal root ganglion, afferent nerve fibres carry info to the brain
12 cranial nerves
Olfactory, optic, ocularmotor, tochlear, trigeminal, abducens, facial, vestibularcochlear, glosspharyngeal, vagus, (spinal) accessory, hypoglossal
