Overview of the Nervous system Flashcards
what is the function of the nervous system
- Gather sensory information from the internal and external environment
- Integrate information for assessment and meaning - this happens in the CNS
- Produce a response
- Regulate body homeostasis for optimal performance – ANS
what is the central nervous system made out of
Central nervous system is made out of the brain, brainstem and the spinal cord which is an extension of the brainstem
what does the peripheral nervous system splits into
somatic and autonomic
what does the somatic nervous system do
mainly controls skeletal muscle
what does the autonomic nervous system do
regulates glands, blood vessels and internal organs
what is the autonomic nervous system divided into
sympathetic and parasympathetic
describe afferent neurones
- Afferent – (sensory) – this takes information from PNS to CNS – cell body outside CNS
describe interneurons
- Interneurons – relays information – this is completely imbedded within the CNS, they interconnect between the afferent and efferent neurones
describe efferent neurones
- Efferent (motor) – this takes the response from CNS to PNS – cell body in the CNS
What is the structure of a typical
- Made up of dendrites – these collect information
- Cell body – synthetic centre this is where the neurotransmitters are made
- Axon – this is the conduction pathway, conducts the action potentials from the cell body to other neurones of the effector organ, only have one axon per neurone
- Axon terminal – release neurotransmitter onto other neurones or effector organ
what are the 6 categories of neurones
- Sensory neurone
- Motor neurone
- Preganglionic automimic neurones
- Postganglionic autonomic neurones
- Local interneurons
- Projection neurones (long interneurons)
for every neurone there are…
10 glial cells
what are the glial cells in the PNS
satellite cells
Schwann cells
what is the role of the satellite cells
support cells body
describe the role of the Schwann cells
these make myelin sheath and insulate the axons prevents the action potentials from dissipating
what are the glial cells in the CNS
oligodendrocytes
astrocytes
microglia
ependymal
what do oligodendrocytes do
these make myelin sheath and insulate the axons prevents the action potentials from dissipating
what do astrocytes do
- support cell body and regulate the environment around the neurones,
- they take up potassium, water and neurotransmitters that are in excess,
- they also form the blood brain barrier
what do microglial cells do
these become activated when they are damaged and they phagocytose pathogens that can harm the brain, therefore they act as the immune cells of the brain
what to ependymal cells do
- these are found lining the ventricular system
- they help to move the cerebrospinal fluid around and line the ventricles helping move the CSF around the ventricular system
what is a difference between neurones and glial cells
A neurone cannot go back into the cell cycle, whereas the glial cells can go back into the cell cycle and regenerate themselves
most brain tumours are…
gliomas
why are most brain tumours gliomas
- This is because the glial cells can undergo mitosis and regenerate
- Schwannoma, astrocytoma, ependymoma and oligodendroglioma
what is the most common primary brain tumour in adults
- Glioblastoma multiforme malignant astrocytoma and most common primary brain tumour in adults
what is epilepsy caused by
- Often caused by malfunction in glial cells (astrocyte scar) in a region where neuronal damage has taken place
what causes Alzheimer’s disease
- Tau in astrocytes and oligodendrocytes
what causes multiple sclerosis
- Autoantibodies attack oligodendrocytes
what diseases can glial cells cause
primary brain tumour
epilepsy
alzheimers
mutiple sclerosis
dorsal
posterior
dorsal horn is the posterior horn and sensory axons enter
ventral
anterior
ventral horn is anterior horn and location of lower motor neuron cell
what is in grey matter
neuronal cell bodies, dendrities, axon terminal, synapses and is highly vascular
what is in white matter
bundles of myelinated axons
where are there groupings of neuronal cell bodies
nucleus - cranial nerve nuclei in the brainstem
ganglion - usually outside of CNS and sensory cell bodies such as the dorsal root ganglia
what does the cortical spinal tract do
Cortical spinal tracts takes information from the primary motor content down and goes into the corticospinal tract and into the spinal cord and then into the various lower motor neurones with the spinal cord
what does the reticular formation do
- Acts as a filter, works out what is important to respond to and what isn’t important to respond to
what does the leminsicus do
- Sensory tract takes stuff up
- Goes the whole length of the brain stem
what turns into the cerebrum
telencephalon
describe the develop of the cerebellum
- As we have become more complex the telencephalon as become more important this turns into the cerebrum
- This is the higher function area
- It folds down over the diencephalon and fuses with it and insula develops over the side of the fusion
what is the insula
this is the awareness centre
- meeting point of the frontal, parietal and temporal lobes
describe the characteristics of the adult ventricular system
- It is supported in a fluid filled space that gives it buoyancy
- It is surrounded with fluid
what Is the ventricular system made out of
4 chambers – 2 lateral ventricles and then the 3rd and 4th ventricles
what are in close proximity to the ventricles
- Basal ganglia nucleic and thalamus
what are the basal ganglia
- Basal ganglia group of subcortical nuclei interconnected to cerebral cortex, thalamus and brainstem
what is the role of the basal ganglia
involved with voluntary movement, procedural learning, routine behaviours (habits) and emotion
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 brainstem do
- breathing
- body temperature
- digestion
- alertness
- 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 broadmann areas
- Identified 53 district regions of the cerebral cortex
- Mainly based on neuronal organisation but have since been correlated with function
what are the motor and sensory homunculi
- Primary motor = frontal lobe
- Primary sensory = parietal lobe
- Separated by the central sulcus – precentral gyrus and postcentral gyrus
- Left cerebral hemisphere communicates with ….
- Left cerebral hemisphere communicates with right side of the body
describe wernickes area
- Comprehension / understanding of written and spoken language
- Brodmann area 22
describe brocas area
- Language production
* Brodmann area 44-45
where are wernickes and brocas area
• Both in left hemisphere
describe what the left hemisphere is involved in
logic
analysis of facts,
understanding of production of language
describe what the right hemisphere is involved in
• Imagination, rhythm, holistic thinking, non-verbal language, emotion in language
what does the corpus callosum do
- Connects cerebral hemispheres
- Extends from enlarged genu in frontal lobe to enlarged splenium in parietal lobe
what does the anterior commissure connect
connects the temporal lobes
what does the internal capsule connect
- Internal capsule runs between lenticular nucleus (basal ganglia) and thalamus / head of caudate
- Route through which information travels to and from cerebral cortex to subcortical sites
what does the thalamus lie and what does it receive input from
- Lies on either side of the 3rd ventricle – forms the wall of the 3rd ventricle
- Receives input from all areas of the nervous system – it is the gateway to the cortex
what lobe of the brain is the limbic system
- 5th lobe of the brain
what does the limbic system do
- Emotion and memory
- Frightening situations—or even memories of such situations—activate the amygdala, as shown in this functional magnetic resonance image (fMRI) of the left side of the brain of a person experiencing fear.
what do deficits in the limbic system lead to
- Deficits in this system leads to autism
how many pairs of cranial nerves are there
- 12 pairs of cranial nerves
* 10 have motor and or sensory nuclei in brainstem
describe the location of cranial nerve nuclei
If your cranial nerve is motor its nucleic is in the centre, if the cranial nerve is purely sensory its nucleic will be on the periphery, if the cranial nerve is mixed it will be in the middle of the sensory and motor
