overview of the nervous system Flashcards
what are the functions of the nervous system?
- gather sensory info from the internal/external environment
- Integrate info for assessment to then produce a response
- Regulate body homeostasis
what are the 2 main divisions of the nervous system?
CNS and PNS
what makes up the CNS?
brain (brain, cerebral cortex and brainstem) and spinal cord
what is the spinal cord an extension of?
the brainstem
what does the PNS do?
transmits information to and from the CNS
what is the PNS divided into?
autonomic
somatic
what is the function of the autonomic nervous system?
regulates glands, blood vessels and internal organs
what is the autonomic nervous system divided into?
sympathetic
parasympathetic
enteric
what is the function of the somatic nervous system?
controls skeletal muscle
what are the functional components of the nervous system?
afferent neurons
interneurons
efferent neurons
what do afferent neurons do?
take information from the PNS to the CNS
where are the afferent neuron cell bodies found?
just outside the spinal cord as dorsal root ganglia
what is the function of interneurons?
relays information to the brain or effector organ
where are interneurons found?
in the CNS
what is the function of efferent neurons?
takes response from CNS to PNS (effector organs – skeletal muscles or glands)
what is the function of dendrites?
collect information
what is the function of the cell body of a neuron?
synthetic centre
what is the function of the axon of a neuron?
conducts action potential from cell body to other neurons/effector organs
how many axons are there per neuron?
one
what are the 6 categories of neurons?
Sensory, motor, preganglionic autonomic, postganglionic autonomic, local interneurons, projections neurons
where are glial cells found?
CNS and PNS
what is the ratio of glial cells to neurons?
10:1
what glial cells are found in the PNS?
satellite cells
schwann cells
what is the function of satellite cells
support cell bodies, regulate environment around the dorsal root ganglia
Take up excess K+, water and neurotransmitters to regulate the ion and water balance and prevent damage from excess NTS
what do schwann cells do?
- secretes neurotrophic factors
- Forms myelin sheaths of the axons of the PNS
- Protects AP so it doesn’t dissipate
what are the glial cells of the CNS?
oligodendrocytes
microglia
astrocytes
ependymal cells
what is the function of oligodendrocytes?
forms myelin sheaths in the CNS
what is the function of microglia?
immune cells of the brain
how do microglia work?
Become activated when there’s an infection act as a macrophage. Phagocytose bacteria that enter through the BBB or dead/dying neurons.
what do astrocytes do?
regulate the environment in the CNS
- Provide substrates for ATP
- Help form BBB -
- Secrete neurotrophic factors
- Take up K+, water and NTS
- Source of neural stem cells
what is the function of ependymal cells?
create barriers between compartments. Line the ventricular system. Help move the CSF around the ventricular system.
how do gliomas form?
uncontrolled mitosis of glial cells which lead to brain tumours
name the types of gliomas
Schwannoma, astrocytoma, ependymoma and oligodendroglioma
what is an astrocyte scar?
when neurons cant be replaced in brain damage, so astrocytes fill in the gap, forming an astrocyte scar
how does an astrocyte scar lead to epilepsy?
Forms barriers between neurons –> malfunction –> epilepsy
which protein is linked to alzheimer’s disease?
tau
what is multiple sclerosis and what effect does it have on the body?
Autoantibodies attack oligodendrocytes and damage them so there’s no myelin around certain neurons –> loss of neuronal signal
what does dorsal mean?
posterior
what does ventral mean?
anterior
what does the corpus collosum do?
connects both cerebral hemispheres
what is grey matter?
neuronal cell bodies, dendrites, axon terminal, synapses
what is white matter?
bundles of myelinated axons
what is the function of reticular formation?
habituation
acts as a filter of what’s important to respond to and what isn’t
which part of the brain is involved in higher function?
forebrain
which part of the brain is more primitive?
hindbrain and midbrain
what is another name for the forebrain?
telencephalon
what is the insula?
meeting point of the parietal, frontal and temporal lobes where they all fold over each other. At the lateral fissure
what does the insula control?
emotions
how many chambers are found in the adult ventricular system
4
where is the CSF made?
lateral ventricles - one in each cerebral hemisphere
what is the function of the frontal lobe?
problem solving, reasoning, emotion and voluntary motor activity
what is the function of the parietal lobe?
sensation
what does the central sulcus separate?
frontal and parietal loves
what is the function of the temporal lobe?
memory and hearing
what is the function of the occipital lobe?
vision
how many brodmann areas are there?
52
what is the primary motor cortex?
frontal lobe
what is the primary sensory cortex?
parietal lobe
what is Wernicke’s area responsible for?
Comprehension / understanding of written and spoken language
which Brodmann’s area is Wernicke’s area?
22
what is the function of Broca’s area?
language production
which Brodmann’s area is Wernicke’s area?
44-45
what does the left cerebral hemisphere control?
the right side of the body
logic, analysis of facts, understanding of production of language
what does the right cerebral hemisphere control?
left side of the body
Imagination, rhythm, holistic thinking, non-verbal language, emotion in language
what is the function of the anterior commissure?
connects the temporal lobes
what is the function of the internal capsule
Route through which information travels to and from cerebral cortex to subcortical sites
where is the thalamus found?
either side of the 3rd ventricle - forms wall of 3rd ventricle
what is the function of the thalamus?
receives input from all areas of the nervous system - gateway to the cortex
what is the limbic system also known as?
the 5th lobe of the brain
a person who is afraid shows increased activity in their?
amygdala
where do most cranial nerves originate from? which do not originate from here?
brainstem
except 1 and 2
how many pairs of cranial nerves are there?
12
how many cranial nerves have motor and/or sensory nuclei in the brainstem?
10