Module 6: Nervous System Flashcards
Hemispheres
There are left and right hemispheres
Left controls right, vies versa
Brain Stem
Function - controls heart rate and respiration
Made up of - pons, medulla oblangata (medulla is continuous with the spinal cord)
Cerebellum
Function -coordinated movement
Diencephalon
Made up of - hypothalamus & thalamus
Bumps
Gyro
Dips
Sulci
Lobes
Parietal, occipital, temporal, frontal
Frontal lobe
Primary motor cortex - process input from skeletal muscles
Motor association area (premotor cortex)
Prefrontal cortex - right in the front
The motor association area and prefrontal cortex generate perception of stimuli
^lateral view visibility includes
Parietal lobe
Primary somatosensory cortex - recieves input form major sense organs
Association areas - integrate sensory info with other association areas of cortex
Cerebellum
process sensory info & coordinates execution of movement & receives input from somatic receptors, receptors for equilibrium, balance and motor neurons from cortex
largest number of neurons
temporal lobe
Primary auditory cortex & auditory association areas work together to receive and process signals from auditory nerve and integrate them with sensory inputs
Plus: involved in smell (olfaction)
Plus: mediate short-term memory storage & recall
occipital lobe
Area of cerebral context
Primary visual cortex Role: vision (receives input from optic nerve)
Visual association areas process visual info and integrates it with other sensory inputs
corpus callosum
Corpus callosum
Dense bundle nerves
Pathway and connection between left and right hemispheres
Allows brain to integrate sensory and motor info from both sides & coordinate whole body movement
pituitary gland
Pituitary gland
Regulates endocrine organs and is regulated by hypothalamus
Anterior pituitary made up of epithelial tissue of pharynx
- Hormones: LH, FSH, ACTH, TSH, GH, prolactin
Posterior pituitary made up of neural tissue of hypothalamus
- Hormones: vasopressin & oxytocin
pons
Red elay station transfer info between cerebellum and cerebral cortex
w/ centres in medulla – coordinates and controls breathing
diencephalon
Thalamus (receive sensory output from spinal cord & integrates sensory info before send to cortex)
Hypothalamus (control endocrine functions like body temp, thirst, hunger, etc)
Midbrain (mesenoephalon)
Bridge lower brain stem with diencephalon
Role: control eye movement and control auditory and visual motor reflexes
medulla
Control involuntary function (breathing, blood pressure, swallowing)
Fibers from corticospinal tract (from motor cortex) cross over to opposite side of spinal cord to innervate muscles on opposite side of body
optic chiasma
Eye to eye meet at optic chiasma
Cross over and continue on as optic tracts to lateral geniculate bodies of thalamus
Axons extend to respective hemisphere on primary visual area of the occipital lobe
brain stem
=Extension of spinal cord
Involuntary function and incorporates 9 cranial nerves
Three regions (see left to right on pic)
- Midbrain
- Pons
- Medulla
bipolar neurons
- 2 process extend from body
- found in retina of eye
unipolar neurons
- one process extending from body
- cell body lives in the middle and off to one side of axon
- located peripheral nerves
- sensory (transmit signal to and from spinal cord)
multipolar neurons
- many branches of dendrites
- most common in CNS
glial cells
- structure role (“glue”)
- nutrient and specific interstitial env regulation role
Perform this by regulating passage of subs. Btw blood and brain’s interstitial space
Types of glial cells :
- Astrocytes
- Microglia
- Oligodendrocytes (produce myelin!)
structure chemical synapse
1. Axon terminal of presynaptic cell Contains: -Voltage-gated Ca++ channels -Synaptic vesicles containing neurotransmitter -Mitochondria
- Synaptic cleft
3. Post synaptic cleft
Contains:
-Chemical receptors
-Chemically gated ion channels
-Open when neurotransmitter binds to them
steps that happen at chemical synapse
Action potential comes
Action potential reaches the voltage-gated Ca++ channels &opens them, allowing Ca++ to come in the cell down its electrochemical gradient
Ca++ causes the vesicles to fuse to the membrane and they release their neurotransmitters via diffusion across the synaptic cleft
NT (neurotransmitter) binds to receptor on post synaptic cell
Binding changes the protein channel associated with the receptor, allowing a specific ion to flow through
Depolarize or hyperpolarization
Protein channels close, NT broken down and taken back up by presynaptic cell to be recycled/used again
Neurotransmitters
Neurotransmitters (NT) chem released by neurons at axon terminals
Synthesized in neuron
Stored in vesicles
Produces a response in the post synaptic neuron
Excitatory response – lead to depolarization firing AP
Inhibitory response – hyperpolarization (make it harder to fire action potential)
4 main types of neurotransmitters
acetylcholine
biogenic amines
amino acids
neuropeptides
EPSPs
- Na+ depolarizes region of dendrite but no action potential is produced because there are no voltage-gated channels on the dendrites or cell body of neuron
spatial summation
additive effect from many EPSPsgenerated at many different synapses on the same postsynaptic neuron at the same time
temporal summation
additive effect many EPSPs generated at the same synapse of high frequency action potentials on the presynaptic neuron
IPSP
hyperpolarization
Either let Cl- come in, or let K+ go out (making the cell become more negative
Proprioception
how receptors in muscles send signals to the brain
motor system structures
Supplementary motor area
Premotor area
Primary motor cortex area
Basal ganglia
Spinal pathways
Motor nerves
Muscle receptors
different functions of motor system structures
Example – seeing coffee and picking it up
Deciding to pick up the coffee – prefrontal cortex
Signals go to premotor cortex – develops strategy for movements needed to pick up cup
Damage to the prefrontal cortex makes it hard for individuals to develop the right strategy to picl something up
primary motor cortex opens sufficient # voltage gated ion channels to reach threshold and start action potential
Supplementary motor cortex programs motor sequence
damage to supplementary cortex
hand assumes awkward positions when trying to pick something up I.e unable to orientate their hands properly
homunculus
Medial to lateral – foot, ankle, knee, thigh, trunk, shoulder, elbow, wrist, hand, fingers, face, lips, jaw, tongue
Signals travel down spinal cord through corticospinal tract
corticospinal tract
major motor pathway of primary motor cortex to motor neurons
