WEEK 4 Flashcards
definition of the nervous system
consists of both the central nervous system and peripheral nervous system
describe the CNS ( x3)
- contains brain and spinal chord
- replies to signal from PNS
- once CNS has received message this is sent through to the motor nerve
describe the PNS ( x2)
brings info to central nervous system
-when sending a signal or change to the CNS this activates the sensory nerve
describe the autonomic nervous system and what are the two divisions
happens automatically
- parasympathetic nervous system
- sympathetic nervous system
what are neutrons
receive messages and transmit them to other cells
what are glial cells
support the neuron to function and keep homeostasis possible
draw a neuron and identify the areas
should include:
- cell body
- soma
- cytosol= fluid
- tree like structure of dendrites
- axon hillock= start of neuron
- myelin sheath= cover around axon to insulate
- vesicle= contain neurotransmitters
describe oligodendrocyte
cell goes around cell body and can make 60 axons at the same time
describe schwan cell
- make myelin sheath with one axon at a time
- more efficient than oligodendrocyte
- repair quite quickly
describe an astrocyte
- star shape
- provide nutrient and structural support for neuron
describe microsatellite cell ( x4)
- provide nutrients
- support cell
- maintain connection
- can be quite sensitive
describe microglia cell ( x3)
- eat bacteria
- phagocytosis
- ensures brain is protected
describe ependymal cell (x2)
- present in the ventricles of the brain
- allow for proper functioning
what is the resting membrane potential and what are the 3 things it depends on
def= the voltage measuring in the neuronal cell
- permeability= anions such as proteins cannot go through
- electrochemical gradient= charge and concentrations of ions
-prescence of sodium and potassium
what is action potential
electrical signals that propagate along axons, through rapid, transient depolarisation of the cell membrane
what is the process of depolarisation
the sodium channels open and flow into the cell, bringing positive electrical charge and increasing membrane potential (-55mv)
what is th process of repolarisation
the potassium channels open which leads to the exit of potassium ions out of the cell ( 30 or 40mv +)
what is the process of hyper polarisation
voltage gates potassium channels take time to close potassium ions continue to leave the neuron which causes the membrane potential to drop below the resting membrane potential ( -7mv) until it reaches -90mv
what does absolute refractory period mean
the second action potential cannot be initiated
what does the relative refractory period mean
the period which the neuron responds to stimulation by very strong stimulus
what are the definition of synapses and describe the two main ones
def= junctions between neutrons allowing them to communicate with one another
- electrical= gap junction. very fast connection present mainly in brain and heart
- chemical= most common one in mammals
what are the 3 essential components in the chemical synapse
- pre synaptic neuron
- post synaptic nueron with neurotransmitter binding sites
- cleft or gap with enzymes to degrade leftover neurotransmitters
what are neurotransmitters
chemical messengers. they are released through exocytosis and bind to specific receptors at the post synaptic neuronal membrane
what are the two main neuro transmitters
1- glutamate= major excitatory neurotransmitter in central nervous system
2- GABA= gamma aminobutyric acid
what are some examples if there is poor regulation of neurotransmitters
parkinsons= not enough dopamine released with uncontrollable movements
depression= if serotonin is not released
BRAIN- what is the dura mater
external layer which is thick, tough and elastic
BRAIN- what is the arachnoid mater=
thin cell layer with arachnoid trabecular, web like collagen
BRAIN- what is the Pia mater
internal layer, thin, delicate, tightly covers all external contours of the brain
BRAIN- what is the thalamus
relay and processing centres
BRAIN- what is the hypothalamus
highest centre for autonomic control
- hormonal regulation
BRAIN- describe the midbrain
important region for motor control and temp regulation
BRAIN- describe medulla oblongata
relays info and contains autonomic centres for regulation of visceral function
BRAIN- describe the corpus callosum
connects the two hemispheres and is made of nerve fibres
BRAIN- describes the cerebrospinal spinal fluid
- 2 lateral vesicles
- the third ventricle is in the diencephalon
what are the two arteries that give brain blood supply
1- vertebral arteries= on left and right join to form the basilar artery which ends by dividing into a left and right posterior cerebral artery
2- internal carotid artery ends by dividing into anterior and middle cerebral arteries
what are the two strokes that occur from blockage in the blood vessels
1- ischemic stroke= blockage vessels
2- hemorrhagic stroke= rupture in the blood vessels or causes bleeding
what are the four main lobes that form the cerebral cortex and describe them
frontal lobe= includes primary motor cortex, essential for motor control and language protection
parietal lobe= includes somatosensory cortex, essential for perception of touch pressure, pain vibration and taste
occipital lobe= includes visual cortex, essential for vision
temporal lobe= auditory and olfactory cortices, essential for audition, olfaction and language comprehension
describe the basal ganglion
a group of nuclei located deep in the cerebral hemispheres
include: curate nucleus, putamen, globus pallidus
- they are essential into motor planning and executing fine voluntary
describe the cerebellum
- structure allows for rapid coordination for movement, automatic adjustments to maintain balance and posture
- coordinates both learned and reflexive patterns on muscle activity
what is brocas area
responsible for production of speech in the frontal lobe
what is gyri
folds in the brain that increases the surface area of the cerebral cortex
what is wernickes area
region responsible for language comprehension
describe the organisation of the spinal chord ( x3)
a major column of nerve tissue lying within the vertebral canal
- divided into segments and numbered as the vertebral column
- two enlargement areas= lumbar and sacrum
name the peripheral nerve number for each part of the vertebrae
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
