Nerves 1 Flashcards
What 2 parts make up the CNS?
- the brain
2. the spinal cord
what does PNS do?
carry peripheral nerves and information into and out of CNS
what 3 systems is the nervous system divided into?
- autonomic nervous system
- somatic nervous system
- enteric nervous system
what is autonomic nervous system?
Involuntary control (e.g. heart rate, breathing, endocrine and exocrine glands)
what is somatic nervous system?
voluntary control (e.g. movement, skeletal muscle and motor neurones involved in movement)
what is enteric nervous system? (often controlled by autonomic division)
involuntary control; in the walls of the digestive tracts in GI tract
what is CNS contained within?
bone (spine or skull)
why is the brain convoluted shape?
to maximise neurone numbers and create big sheets of neurones (increasing neurone connections through maximising surface area)
what are 4 lobes found in the brain?
- frontal
- occipital
- temporal
- parietal
what is the function of frontal lobe?
controls behaviour, personality, creates thoughts/emotions, coordinates information from other association areas, contains pre-motor cortices
what is the function of parietal lobe?
contains sensory information from muscoskeletal system, viscera and taste buds (has somatosensory system/cortex)
what is the function of the temporal lobe?
combines auditory and visual data (contains primary auditory complex)
what is the function of the occipital lobe?
interprets light signals in your eyes into shapes and patterns (contains primary visual cortex)
what is the function of the meninges?
- contain CSF to support the brain
- contain no ligaments to hold it in place
- membranes found around the brain and the spinal cord
what is the gyrus?
the top part of the high/top part of the cerebral cortex
what is the sulcus?
the low part of the high cerebral cortex?
what is the function of the cerebellum?
- balance and coordination
- motor control
- coordinates movement, muscle tone control, posture etc
what is the function of the cerebrum?
- 4 lobes make it up and on the frontal side of the brain
- thoughts and emotions formed there
- contains integrated sensory complex and neural functions
What two parts is the diencephalon composed of?
- thalamus
2. hypothalamus
What two glands does the diencephalon contain?
- pituitary gland
2. pineal gland (where melatonin which regulates our 24hr body clock is produced)
what is the function of the thalamus?
- transmits sensory info and serves as a relay station for information going to and from higher brain centres
- projects fibres to the cerebrum where info is processed
- can modify sensory info from regions such as optic tract, ears, spinal cord and motor info from cerebellum
- It’s an INTEGRATING centre
what is the function of the hypothalamus?
- site of homeostasis
- integrates hormonal and nervous systems together for thermal control, fluid control etc.
what are the 3 brain stems?
- midbrain
- pons
- medulla oblongata
what functions is the midbrain associated with?
part of CNS associated with motor, hearing, vision and temperature control/regulation
what is function of pons?
connect two sides of the cerebral cortex (connect forebrain to cerebellum)
what is function of medulla oblongata?
heart rate and breathing (involuntary actions keeping us alive) + cardiovascular system control
how many VERTEBRAE are there in the spinal column?
33 vertebrae
what are the 33 vertebrae split into? how many in each section of vertebral column?
cervical: 7
thoracic: 12
lumbar: 5
sacral: 5
coccyx: 4
how many SPINAL NERVES are there in the vertebral column?
31 spinal nerves
What are the 31 spinal nerves split into in each section of vertebral column?
cervical: 8
thoracic: 12
lumbar: 5
sacral :5
coccyx: 1
which two regions of spinal cord are the thickest because of need for movement?
Cervical and lumbar regions
which route does sensory info flow into?
dorsal route (TOP)
which route does motor info travel out of?
ventral route (BOTTOM)
what is a ganglion?
set/ group/cluster of cell bodies
what is the main ganglion found on the posterior root of the spinal nerve?
dorsal root ganglion
what is in the white matter? (outside)
axons (myelinated)
what is in the grey matter? (inside)
cell bodies/ neurones
what are afferent nerve fibres?
sensory nerve fibres
what are efferent nerve fibres?
motor nerve fibres ( e=exit)
in the middle of the spinal cord, what is the jumble of cells called?
inter-neurones
what is the name for a neurone cell body?
soma
what is the function of soma? (2)
- contains the nucleus
- cytoprotein production site
what is the function of dendrites?
- receive info from other neurones
connection between 2 neurones
what is the function of an axon hillock (initial segment)?
- triggers action potential
- all info needed for an AP is arranged there
what is the function of an axon?
- sends AP (conducts electrical impulses away from the cell body and transmits information)
- Na gated channels which fire AP are initiated there and sent AP to a distant site
what is the function of axon pre-synaptic terminal?
releases neurotransmitters which act on the next nerve cell to make a new electrical signal
what are 3 main types of neurones?
- afferent (sensory) neurones
- interneurones
- efferent (motor) neurones
where are afferent/ sensory neurones found and what is their function?
Found in PNS; detect things in environment
where are interneurones found and what is their function?
found in CNS; decide what to do with the signal
where are efferent/motor neurones found and what is their function?
found in PNS; sends signal and responds to the stimulus
describe how a signal travels through the spinal cord (what nerves and routes involved)
- stimulus sends signal to sensory neurone/afferent neurone along DORSAL route to the CNS
- the signal travels into VENTRAL route, through the motor/ efferent neurone and to the effector into PNS
what percentage of nerve cells in body are glia?
90%
what is the function of glia? (2)
- provide structure and support for neurones (physical and biochemical)
- help maintain homeostasis of the brain’s extracellular fluid by taking up excess brain metabolites and ions
what are 4 types of glia?
- astrocyte
- oligodendrocyte
- microglia
- ependymal cells
what is the function of an astrocyte?
- maintain external environment for neurones
- surround blood vessels and produce blood brain barrier
- “keep neurones happy”
- maintain extracellular ion conc.; make capillaries tight to prevent ion leakage around CNS neurones (take up K and neurotransmitters)
what is the function of oligodentrocytes?
- form myelin sheaths in the CNS
- they’re wrapped around neurones and involved in myelination process
what is the function of microglia?
- phagocytic hoovers which “mop up” infection
- secrete antibodies in presence of infection and engulf pathogens
what is the function of ependymal cells?
- pruduce CSF
- separate fluid compartments in the CNS
- have big surface area
