11.1 The Nervous System Flashcards
What can a pituitary stalk tumour have an affect on?
Can press on optic nerves affecting peripheral vision
What is the cauda equina and its function?
Within the lumbar cistern, part of the PNS
Motor innervation of pelvic organs and lower limbs
Sensory innervation of perineum (area between scrotum/vulva and anus) and bladder
What is a schwannoma?
Tumour of the myelin sheath
It could cause compression on other nerves causing pain and progressive deterioration of neurological function
What is a lumbar puncture and why is it done between L3 an L4 region?
Sample of cerebrospinalfluid taken to see if infection in CNS region.
Least risky place to do it as cauda equina is here and we’d rather hit a PNS nerve than CNS
What is a deep tendon reflex and its physiological role?
blow to the tendon causing quadriceps femoris muscle contraction, and hamstring to relax
If knee gives way, it is an automatic unconscious movement to regain balance
What is a glioblastoma?
Cancer of glial cells in brain
If tumour in cranial region, what happens to the intracranial pressure?
It is normally 7-15mmHg
Tumour increases this although pressure increase in one constituent is responded to by a decrease in another.
But once this compensatory reserve is exceed, pressure for a given increase in volume rises dramatically.
What is a craniotomy?
Surgical removal and replacement of part of bone from skull
What does the CNS and PNS consist of?
CNS - The spinal cord and the brain
PNS - Somatic nervous system and Autonomic Nervous system (Sympathetic and parasympathetic)
Function of the CNS and PNS?
CNS - in charge, make sensible motor responses based on sensory input.
PNS - converys sensory input to CNS and sends motor output to the muscles
I.e. Receiving info and Dissemination info to diff parts of body
What is the function of the brain?
Cerebral cortex - responsible for higher functions
What is the function of the brain stem?
Consists of medulla oblongata, pons, mid brain
Controls flow of messages between brain and body
Regulation of cardiovascular function, breathing, sleep, wakefulness
What is the cerebellum and its function?
Highly folded so lots of neurones can fit here
In charge of fine aspects of motor control
What does the spinal cord do?
Carries sensory and motor information to and from the CNS
What are ganglia and nuclei?
Collection of neuronal cell bodies within the PNS
Collection of neuronal cell bodies within the CNS
What are nerves called in the CNS?
Tracts
What is the central canal?
Spinal cord is a hollow tube in the middle, this is called the central canal
What is the difference between white and grey matter?
Grey matter- composed of neurones, information processing computer
White matter - composed of axons, disseminate info to where it needs to go - like cables
Describe a transverse section through the spinal cord.
Central canal surrounded by grey matter surrounded by white matter. Dorsal and ventral roots coming out of spinal cord which connect forming a spinal nerve. The dorsal root has a function called the dorsal root ganglia.
What is the dorsal horn and root, and its function?
Sensory information travels from receptor through the spinal nerve, to the dorsal root ganglion, through dorsal root, to the grey matter lobe (dorsal horn).
What is the ventral horn/root and its function?
Motor information travels from grey matter (ventral horn) through ventral root to spinal nerve where it goes and effects the relevant tissue/muscle
What is an interneurone?
Neurone connecting sensory and motor neurons
Located within grey matter
Where complex processing occurs
Describe the structure of a nerve.
Axon covered by myelin sheath
Axons held together by endoneurium forming fascicles
Fascicles held together by perineurium forming spinal nerve
Spinal nerve wrapped in epineurium
Goes on to form dorsal and ventral rootlets
Which connect to the spinal cord
What is the glia?
Connective tissue of the nervous system made up of lots of different cells
What is a schwann cell,the two types and their functions?
1) produces myelin which is made of lipid
2) myelinating
- insulates axon
- one cell to one axon
3) non-myelinating
- supporting (not really insulation)
What is an oligodendrocyte and its function?
1) produces myelin made of lipid
2) in the CNS
3) one cell insulates MANY axons
What is an astrocyte?
1) cellular vacuum
- vacuums excess NT diffusing away from synapses so cant go an activate elsewhere
2) blood brain barrier
- end feet of astrocyte cover blood vessels preventing certain molecules from getting through to brain and spinal cord
What is a microglial cell?
Fine branched processes on cell constantly moving and protecting CNS
Turns into a macrophage if it comes across anything foreign
