Nervous system Flashcards
describe the division of the nervous system
there is the CNS and the PNS
- CNS divides into the brain and spinal cord
- PNS divides into the somatic and autonomic nervous system
- autonomic system divides into the sympathetic nervous system and the parasympathetic system
what is the central nervous system responsible for
- The central nervous system is responsible for integrating processing and coordinating sensory data,
what is the somatic nervous system
- The somatic nervous system is the voluntary nervous system which controls skeletal muscles
what is the autonomic nervous system
- The autonomic nervous system is the non-voluntary nervous system it controls - glands - blood vessels - internal organs
what is the sympathetic nervous system
this mobilises body for action and has energy output, this is the fight or flight response
what is the parasympathetic system
this conserves energy and maintains a quiet state, this is the relaxing part of the nervous system
what is the nervous system made up of
made up of neurones which have different sizes and functions but they all have the same basic body plan
what does the change in size and shape depend on
- Change in size and shape depends on how many dendrites (sensory processes) that they have
what do dendrites do
picks up the sensory information from the relay or the peripheral and taking it to the cell body and sending an electrical information down the axon either to another neurone or skeletal muscle
what do small neurones act as
the small neurones act as a relay between other neurones
what is the ratio of neurone to glia
1 neurone to 9 glia
what do glia do
- Glia cells are cells that package cells in the nervous system (glue and hold neurones in place and support neurones and protect neurones)
what do the oligodendrocytes do
are myelinating, send out myelin that wrap around axons, found in the CNS
what do the astrocytes do
regulate extracellular fluid and environment around the neurones and protecting the neurones, form a blood brain barrier and help protect and regulate what gets in from the blood supply into the rest of the brain
what do the microglia do
protect brain from infection, usually don’t do much and are silent and switched off because the astrocytes is forming the barrier, if something breaks through the barrier then they become active and phagocytose the dead tissue and protect the brain from the infection and damage spreading
what does the ependymal do
line fluid filled cavities in the brain and important for regulating the fluid and moving the CFS fluid around the brain and spinal cord. CFS full of nutrients and keeps the buoyancy of the brain light
what are the specialised cells in the PNS
- The axons are myelinated by schwann cells, wrap around axon insulating it and protecting it therefore keepting the electrical activity inside the cell
- Satellite cells are the alternative to astrocytes which are found around the cell body in the PNS which support the cell body
- General macrophages and the rest of the immune cells protect the nervous cell as there is no blood brain barrier
what type of blood supply does the brain have
dual blood supply
what part of the brain do the internal carotid arteries supply
- there are left and right internal carotid arteries that supply the front part of the brain and the anterior circulation
what part of the brain do the 2 vertebral arteries supply
come up the back of the vertebra, they fuse into the single artery called the basilar artery this goes up the brain stem and divides (back into 2) into the posterior cerebral arteries this does 1/3 of blood supply, back of the brain such as the cerebellum and brain stem
what interconnects the arteries in the brain
- Interconnected such as the posterior and anterior communicator arteries.
what is the vein in the brain called
cerebral veins
describe the job of the cerebral vein
- collecting the Venus drainage
- once oxygenated blood has been round the brain and has picked up carbon dioxide and other waste products this is removed by this cerebral vein. The cerebral vein is reliant on gravity to bring the blood flow back from the brain, the blood goes into the sinus and then through the jugular foramen where the internal jugular vein starts.
what are the sinuses
folds in the dura
what are the three layers of the dura
Dura marta
arachnoid marta
pia marta
describe the arachnoid Marta
this is the spiders layer looks like a spider layer that has been thrown over surface of the brain,
describe the Pia Martra
layer we cant see)– stuck on surface of the brain and goes into the indentations that we have in the brain.
where is the CFS found
found between the Pia and arachnoid
what separates the frontal and parietal lobe
central sulcus
what are the folds called in the brain
sulci
what are the ridges in the brain called
gyri
what do the sulci and gyri do
they increase the surface area in the cerebral hemisphere
what is the aim of the cerebral hemispheres
- Cerebral hemisphere is amount higher function which is conscious function, this is the things that we are processing that we are aware about
what are the higher functions of the nervous system
- Memory
- Emotion
- Coordination of complex movement
- Language compression and production
- Processing of multisensory information
- Detection of visual stimuli
what does the frontal lobe do
- Problem solving
- Emotional traits
- Reasoning
- Speaking
- Voluntary motor activity
what does the temporal lobe do
- Understanding language
- Behaviour
- Memory
- Hearing
what does the brain stem do
- Breathing
- Body temperature
- Digestion
- Alertness/sleep
- Swallowing
what does the parietal lobe do
- Knowing right from left
- Sensation
- Reading
- Body orientation
what does the occipital lobe do
- Vision
- Colour perception
what does the cerebellum do
- Balance
- Coordination and control of voluntary movement
- Fine muscle control
what are the deeper parts of the Brain
thalamus
hypothalamus
brain stem
describe the grey matter
cell body and nucleuses and white matter is where myelinated axons are
what connects the left and right side of the brain
corpus collosum
what is the white matter tract
- White matter tracks go through deeper part of the brain and this is called the internal capsule – where all info from the peripheral is coming in and going up to the brain and where the motor is coming down and going out to the periphery - important white matter tract
what is the thalamus
is a relay station, takes info from the internal capsule and decides which part of the brain it needs to go to and will relay it to the right part of the body plan and right part of the brain to get the right response
what does the brain stem do
- Provides main motor and sensory innervation to the face and neck
- Conductive functions (ascending and descending tracts carry information to and from the cortex to the periphery)
- Connection with rest of the brain and where most of the cranial nerves exit apart form the olfactory and optic come out in front of the brain stem
- Cranial nerves form 3-12 come from the brain stem
what is the brain stem made up of
- Brainstem made up of midbrain, pons (which is the bridge), below the bridge is the medulla oblongata, and then the spinal cord is just a continuation
- Reticular formation part of integrative functions and is a sensory filter for what is important and what isn’t important, decides if we need to respond to something.
- Ascending and descending tracts go through the brain stem and though the internal capsule, go down or up the brain stem.
what are the cranial nerves that you need to know
- cranial nerves that are involved in the parasympathetic system
- CN III – pupil size and lens focusing – vision
- CN VII – salvia production – facial
- CN IX – saliva production – facial
- CN X – about everything else (90% of parasympathetic nervous system) – vagus nerve
where does the spinal cord start after the brain
- Spinal cord continuation of the brain stem, comes out foramen magnum, brain stem transitions into the spinal cord.
- Spinal cord starts 2cm below foreman magnum brain stem comes out of the foramen magnum
what are there at regular intervals in the spinal cord
at regular intervals there are the entrance and exit points for the peripheral nervous system
where does the sensory spinal information come up from
- Sensory information comes up through the dorsal root into the cell bodies which are housed outside the spinal cord.
where does the information go in the spinal cord
- Some of the information go to the ascending and descending tracts information from the brain. Some of the information goes to the ventral root which is mainly motor neurones and they exit from the ventral root and go down
whats another word for ventral
Anterior
whats another word for dorsal
posterior
where do ascending tracts go
sensory and go up towards the brain
where do descending tracts go
motor and come down from the brain
where are the ascending and descending tracts
- Ascending and descending tracts are outside the grey matter (in the centre of the spinal cord)
- They form part of the internal capsule
what is the dermatome
an area of skin innervated by axons from a single spinal nerve root
what are plexi
- Single spinal root does not have enough motor neurones to make a muscle perform a function,
- Bundle several spinal roots together where there is complex activity that we need to coordinate, gives us more control and more movement these are called plexi
Name the three plexi
- Cervical plexus – controls movement in the neck
- Brachial plexus – controls movement in the arm
- Lumbar plexus – controls movement in the leg
- sacral plexus
are peripheral nerves mixed
- Peripheral nerve is mixed from different spinal nerve levels, this gives us complexity of movement and more control over movement.
what is a trunk
single spinal nerve
why do we not need plexi in the thorax
- In the thorax where there are big simple muscles then there is no need for the plexi and the thoracic nerves are the single spinal nerves
what does the parasympathetic nervous system do
- Constrict pupils
- Stimulate saliva
- Slow heartbeat
- Constrict airways
- Stimulate activity of stomach
- Inhibit release of glucose; stimulate gallbladder
- Stimulate activity of intestines
- Contract bladder
- Promote erection of genitals
what do the sympathetic nervous system do
- Dilate pupils
- Inhibit salivation
- Increase heartbeat
- Relax airways
- Inhibit activity of stomach
- Stimulate release of glucose; inhibit gallbladder
- Inhibit activity of intestines
- Secrete epinephrine and norepinephrine
- Relax bladder
- Promote ejaculation and vaginal contraction
describe the parasympathetic craniosacral
- One to one system
- Vagus nerve controls 90% of the parasympathetic system
- Sometimes called the craniosacral because there is sacral outflow from S1, S2, S4 in spinal cord
where does the parasympathetic craniosacral go
- Goes to heart, lungs, spleen, kidney, small intestine, liver, stomach, colon
describe the sympathetic thoracolumbar
- Sympathetic is called the thoracolumbar, outflow goes out from T1-L2 they hitch a ride of spinal nerves
- Comes out by the thoracolumbar – more complex integration not a one to one system
where does the sympathetic thoracolumbar go
- go to the heart, lungs, liver, stomach, large intestine and bladder, some goes back up to the head to the eyeball
describe the balance between the sympathetic and parasympathetic systems
- are active all the time,
- the effect is controlled by which is most active, they. Both have noticeable and hidden effects
