Nervous System Flashcards
What are the two main divisions of the nervous system
Central nervous system
peripheral nervous system
what are the 3 sub divisions of the peripheral nervous system
somatic
autonomic
enteric
describe the sensory and motor pathways of the somatic nervous system
sensory: somatic and special sense receptors to to CNS
motor: info from CNS to skeletal muscle
describe the sensory and motor pathways of the autonomic nervous system
sensory: receptors in visceral organs
motor: intro from CNS to cardiac and smooth muscle and glands
how is the autonomic nervous system divided
sympathetic and parasympathetic
describe the sensory and motor pathways of the enteric nervous system
sensory: motor chemical changes and stretch in GI tract
motor: innervates smooth muscle and glands and endocrine cells in GI tract
what are the 6 main structures of the neuron
cell body (soma)
dendrites
Axon
node of ranvier
Axon terminals
synaptic end bulb
what are the 3 types of neurons
multipolar neuron
bipolar
unipolar
what are the 6 types of neuroglia
astrocytes
oligodendrocytes
microglia
ependymal cells
Schwann cells
satellite cells
what are the 5 types of channels
leak channel
ligand-gated channel
mechanically-gated channel
voltage-gated channels
sodium-potassium pump
describe the leak channel
randomly open and close, letting ions specific to the channel to slowly leak in/out
describe the ligand-gated channel
open/close in response to a ligand/chemical; neurotransmitters, hormones, ions can be the stimulus for them to open/close
describe mechanically-gated channels
opens/closes due to mechanical stimulation such as vibrations, pressure on skin, stretch tissue
describe voltage-gated channels
open in response to voltage change
(open, inactive, close)
describe sodium-potassium pump
restoration and maintenance of resting membrane potential
describe the resting membrane potential
the summary of the amount of positive or negative ions on both the inside and outside of the cell
describe the graded potential
small deviation in resting membrane potential making it less or more polarised
describe summation
graded potentials added together, summating to create a bigger one
describe an action potential
sequence of rapidly occurring events that decrease or reverse membrane potential and restores it to resting state
describe what the threshold is
the summated membrane potential needs to meet this mark to create an action potential
describe the sequence of events for an AP with the voltage-gated channels
resting: Na and K channels closed.
depolarisation: Na channels open, Na moves into cell.
Depolarisation: Na channels inactivated. K channels open and move into cell.
Hyperpolarisation: Na channels closed. K channels still open and exiting cell.
Resting: Na and K channels closed. Na/K pumps restore resting potential
what are the two refactors periods of AP
absolute refractory period
relative refractory period
describe absolute refractory period
Na channels are already open so it can’t be open any further, and needs to close before opening again to start new AP
describe relative refractory period
second AP can occur but only by a larger than normal stimulus
what is propagation
AP in neurone must travel from where they arise in neuron to muscle or gland
what is continuous propagation
occurs in unmylinated axons; must occur in each segment of the axon
what is saltatory propagation
occurs in myelinated axons; the AP can “jump” over the myelin sheaths to the other nodes of ranvier - faster
what is a synapse
where neurons connect and communicate with each other
describe an electrical synapse
AP conducted directly between plasma memb of adjacent neurons through gap junctions. allows for fast communication and to be synchronised
describe a chemical synapse
pre and post synaptic cells are separated by synaptic cleft which is filled with interstitial fluid
what are the 7 steps of a chemical synapse
- AP arrives at axon terminal
- voltage gated Ca channels open
- Ca enters the cell
- Ca signals to vesicles
- vesicles move into the membrane
- docked vesicles release neurotransmitter by exocytosis
- neurotransmitter diffuses across the synaptic cleft and binds to receptors
what is the excitatory postsynaptic potential
a depolarising postsynaptic potential. brings the postsynaptic memb closer to threshold
what is the inhibitory postsynaptic potential
a hyperpolarising postsynaptic potential. takes thepostsynaptic memb further from threshold
what is the trigger zone
net summation of EPSPs and IPSPs determines whether an action potential is generated here
what are the three cranial meninges layerings
dura mater
arachnoid mater
pia mater
describe the blood-brain barrier
endothelial cells with tight junctions, a thicker basement memb and end-feet of astrocytes surround the capillaries of the brain - separates brain tissue from harmful substances in blood
describe the circle of willis
circular arrangement of interconnected arteries at the base of the brain to ensure a continuous supply of blood throughout the brain
describe cerebrospinal fluid
clear fluid that protects brain from chemical and physical injury
what is the pathway of CSF
lateral ventricle
third ventricle
fourth ventricle
central canal
subarachnoid space
outside of spinal cord and brain
back to Venus sinuses to be reabsorbed
what are the three parts of the brain stem
medulla oblongata
pons
midbrain
what are the four parts of the cerebrum
frontal lobe
parietal lobe
occipital lobe
temporal lobe
what are the three parts of the diencephalon
thalamus
hypothalamus
epithalamus
function of the medulla
contains all sensory motor tracts
function of the pons
contains pontine respiratory group
function of the midbrain
contains superior and inferior colliculi
function of cerebellum
coordination of movement, balance and posture
function of thalamus
relay station for sensory input
function of hypothalamus
major regulator of homeostasis
function of epithalamus
contains pineal gland
function of frontal lobe
houses motor cortex
function of parietal lobe
houses primary somatosensory cortex
function of occipital lobe
houses visual cortex
function of temporal lobe
houses hippocampus
function of corpus callosum
connects left and right hemisphere
function of lateral ventricles
produces CSF, as if contains choroid plexuses
function of motor cortex
initiate all voluntary movements (pre)
function of somatosensory cortex
processes and interprets all somatic senses (post)
what is a gyrus
bridge in cerebrum
what is a sulcus
small indent in cerebrum
what is a fissure
large indent in cerebrum
mnemonic for cranial nerves - order of nerves and then order of what kind of nerve they are
On on on they travelled and found Voldemort guarding very ancient horses.
some say marry money but my brother says big boobs matter more
describe the protective coverings of the spinal cord
vertebral foramen; vertebra stacked together to form a tunnel for the cord to ru through
intervertebral foramen; the holes between the vertebra for the nerves to exit
meninges; same layers of protection as the brain
epidural space; between dura mater and vertebra
what are the two enlargement ares of the spine
cervical enlargement - where nerves to and from the upper limbs arise
lumbar enlargement - where nerves to and from the lower libs arise
describe the posterior (dorsal) horns
contains cell bodies and axons of interneurons and axons of incoming neurons
describe the anterior (ventral) neurons
contains somatic motor nuclei, providing nerve impulses for contractions of skeletal muscles
describe the lateral horns
contains autonomic nuclei to regulate the activity of cardiac muscle, smooth muscle and glands
what are the three divisions of the white matter of vertebra
anterior (ventral) columns
posterior (dorsal) columns
lateral columns
what are the parts of the spinal nerve that connect to the white matter
posterior (dorsal) root - rootlets ; contains sensory axons
what are the parts of the spinal nerve that leave the white matter
anterior (ventral) roots - tootles ; take nerve impulses from CNS to effectors
what is a ganglion
the swelling section of a posterior root ; contains cell bodies of sensory neurons
what are the 3 layers of the spinal nerve
endoneurium
perineurium
epineurium
what is the bundle of endonmesiumcalled
fascicles
what are the 3 different rami branches called once the nerve has passed the intervertebral foreman
posterior (dorsal)
anterior (ventral) ramus
meningeal branch
what is a plexus
the anterior ramus axons that form a network with other axons
what is the purpose of plexuses
enhance efficiency and flexibility of nerve system, by allowing different fibres to mix and ensures that if one never is damaged, it can still function
what are the divisions/pathway of the nerves
roots (plexus)
trunk
anterior division
posterior division
cord
branches
what is the dermatome
area of skin which is mostly supplied by a single spinal nerve
what are the 3 ways receptors can be classified
microscopic structure
location and origin of stimuli
type of stimulus detected
describe the muscle spindle
monitor the change in length of muscle and participate in the stretch reflex
describe the Golgi tendon organ
monitor change in muscle tension
what are the 5 types of stimulus to be detected
mechanoreceptors
thermoreceptors
nociceptors
photoreceptors
chemoreceptors
what are mechanoreceptors
mechanical stimulus - deformation, stretching, bending
what are thermoreceptors
changes in temp
what are nociceptors
painful stimulus due to physical or chemical damage to tissue
what are photoreceptors
detect light that hits the retina of the eye
what are chemoreceptors
detect chemicals in mouth, nose and body fluids
describe the general sensory pathway
first order neuron; receptor to brainstem/spinal cord
second order neuron; brainstem/spinal cord to thalamus
third order neuron ; thalamus to primary somatosensory cortex
describe the posterior column-medial lemniscus
sensory impulses for touch, pressure, vibration and proprioception from limbs, trunk, neck and posterior head
- 1st order neuron extend from receptors to medulla on same side
- 2nd order neuron decussate in medulla and extend to thalamus
- 3rd order neuron project from thalamus to primary somatosensory cortex
describe anterolateral (spinothalamic)
sensory impulses for pain, temp, itch, tickle from limbs, trunk, neck and posterior head
-1st order neuron extends from receptors to spinal cord on same side
- 2nd order neurons decussate in spinal cord and extend to thalamus
-3rd order neurons project from thalamus to primary somatosensory cortex
describe trigeminothalamic
sensory impulses for pain pain, temp, itch and touch from the face, head and oral cavity
-1st order neuron extends from receptors to spinal cord on same side
2nd order neuron decussate in spinal cord and extends to thalamus
3rd order neuron projects from thalamus to primary somatosensory cortex
describe anterior and posterior spinocerebellar
transmits nerve impulses from proprioceptors in the trunk and lower limbs to the cerebellum. allows for coordination of movement and maintenance of posture and balance
what are the 2 direct somatic motor pathways
corticospinal (lateral and anterior)
corticobulbar
what are the 4 indirect somatic motor pathways
rubrospinal
tectospinal
vestibulospinal
reticulospinal (medial and lateral)
describe the lateral and anterior corticospinal pathway
conduct motor impulses for the control of skeletal muscles in the limbs and trunks;
axons that decussate in medulla innervate muscle in distal limbs. axons that decussate in the spinal cord innervate muscles in trunk and proximal limbs
describe each of the indirect somatic motor pathways
rubrospinal - innervates muscles controlling precise movements of distal upper limbs
tectospinal - innervates muscles which reflexively move head, eyes and trunk
vestibulcochlear - innervates muscles relating to posture and balance in response to head movement
medial and lateral reticulospinal - innervates muscles relating to posture and muscle tone in response to body movement
describe the corticobulbar pathway
conducts motor impulses for the control of skeletal muscles in the head including eye, tongue and neck;
lower motor neurons extend to skeletal muscle through 9 pairs of cranial nerves
what is the reflex arc
rapid involuntary response to stimulus that occurs automatically without thought
what are the 5 steps of a reflex arc
sensory receptor; responds to stim by producing a receptor potential
sensory neuron; axon conducts impulses from receptor to integrating centre
integrating centre; one or more regions within the ins relay impulses from sensory to motor neurons
motor neuron; axon conducts impulses from integrating centre to effector
effector - muscle or gland that responds to motor impulses
what are the classifications of reflexes
development, processing site, nature of response, side of body, complexity
describe steps of stretch reflex
stretching stimulates sensory receptor.
sensory neuron excited.
within integrating receptor, sensory neuron activates motor neuron.
motor neuron excited.
effector contracts and relieves the stretching.
describe steps of tendon reflex
increased tension stimulates sensory receptor.
sensory neuron excited.
within integrating genre, sensory neuron activates inhibitory interneuron.
motor neuron inhibited.
effector relaxes and relieves excess tension
describe steps of crossed extensor reflex
stepping on tack stimulates sensory receptor in foot.
sensory neuron excited.
within integrating centre, sensory neuron activates several interneurons.
motor neuron excited.
effectors contract
what is the main difference between somatic and autonomic nervous systems
somatic - one division; singular motor neuron from brainstem innervates the effector
autonomic - two divisions; parasympathetic and sympathetic
describe the sympathetic division
fight or flight
supports rapid production of ATP
‘E’ Activities
describe the parasympathetic division
rest and digest.
breed and feed.
conserve and restore energy.
‘D’ activities
describe the sympathetics origin of fibres, location of ganglia length of preganglionic fibres, length of postganglionic fibres
thoracic and lumbar spinal cord
close to spinal cord
short preganglionic fibres
long post ganglionic fibres
describe the parasympathetics origin of fibres, location of ganglia length of preganglionic fibres, length of postganglionic fibres
brain and sacral spinal cord
close to or within effector
long preganglionic fibres
short postganglionic fibres
