Final Exam LOs 4 + 5 + 6 Flashcards
Central Nervous System (CNS)
think the brain and the spinal cord, it integrates and processes sensory information to coordinate a motor response
Peripheral Nervous System
it houses the sensory receptors from sensory organs (eyes, ears, etc.), and it has many divisions under it, the main one being the afferent and efferent division (houses autonomic and somatic divisions)
Autonomic Nervous System (ANS)
controls subconscious actions (contraction of smooth muscle + cardiac muscle, and glandular secretions)
also houses the sympathetic division “fight-or-flight”
and the parasympathetic “rest-and-digest”
Somatic Nervous System (SNS)
controls VOLUNTARY an involuntary (reflexes) of skeletal muscle contractions
Neurons
cells that send and receive signals
Cell body of neuron
performs the basic functions of the nervous system
Axon
is long and carries electrical signals (action potential) to target
Dendrites
highly branched, many fine processes, receives info from other other neurons
Axon-terminals
also called synaptic terminals, plays a role in communication with other cells
Synapse
area where a neuron communicates w/another cell
Presynaptic cell
neuron that sends a signal via neurotransmitter (NT)
Postsynaptic cell
neuron that receives message from presynaptic cell
synaptic cleft
the small gap that separates the presynaptic membrane and the postsynaptic membrane
Axon hillock
this is where threshold -55 mV is met, and action potential is triggered at the axon hillock
Neuroglia cells
they are cells that support and protect neurons found in CNS and PNS
Neuroglia found in PNS
satellite and schwann cells
Satellite cells
found in the PNS, they surround neuron cell bodies, regulate oxygen and carbon dioxide, nutrient, and NT levels around ganglia.
Schwann Cells
found in the PNS, they surround axons and are responsible for their myelination
Neuroglia found in CNS
Ependymal cells, Astrocytes, Oligodendrocytes, and Microglia
Ependymal Cells
found in the CNS, they make cerebral spinal fluid (CSF)
Astrocytes
found in the CNS, they help w/the Blood Brain Barrier (BBB)
Oligodendrocytes
myelinate CNS axons, and provide structural framework
White Matter in CNS
dominated by myelinated axons
Grey Matter in CNS
areas containing neuron cell bodies, dendrites, and unmyelinated axons
Three important concepts regarding membrane potential
1) extracellular fluid (ECF) and intracellular fluid (cytosol) differ greatly in ionic composition
2) cells have selectively permeable membranes
3) membrane permeability varies by ion
Resting Membrane Potential
membrane potential of an undisturbed cell, ions move through leaky channels
Thinking about transmembrane potential…
1) inside the membrane is always more negatively charged to the outside of the membrane
2) there’s more sodium OUTside of the cell, so it’s going in, and theres more potassium INside of the cell so it’s going to leave
3) mechanisms that contribute to changes in resting membrane potential is graded potential and action potential
Graded potential
any stimulus that opens a chemically or mechanically gated channel that allows ions to move across the membrane
it can just be a bunch of signals being received, but IF stimulus is strong enough it can lead to action potential at the axon hillock (ex. NMJ and postsynaptic potentials)
Action Potentials
propagated changes in transmembrane potential, happens at the axon hillock
Chemically Gated Channel
open in presence of specific chemicals at binding site
Mechanically Gated Channel
respond to membrane distortion, found in sensory receptors (touch, vibration)
Voltage Gated Channels
responds to changes in transmembrane potential, has an activation state and inactivation state
Depolarization
this is when sodium channels (voltage gated) open and sodium enters the neuron so it becomes more positive (depolarizes), and once it hits threshold (-55mV) that’s when AP starts
Repolarization
when the membrane becomes too positive, the voltage gated sodium channels close, and then the potassium voltage gated channels open so potassium leaves the membrane, making the inside more polar (neg) and it goes back to around -70 mV
Hyperpolarization
this is when occurs because potassium take too long to close and I’m pretty sure it dips a little below -70mV before returning to -70mV
For each phase of action potential, describe both the role of voltage-gated ion channels and the movement of sodium and potassium ions
1) depolarization to threshold (via graded potential): basically a bunch stimulus initiate action potential by changing threshold to around -55 mV which opens the sodium voltage gated channels
2) Activation of sodium channels: causes sodium to flood into the cytoplasm, rapid depolarization as the inner membrane become less neg. and more pos.
3) inactivation of sodium channels and activation of potassium channels: when the membrane gets too pos. at 30 mV, the sodium channel closes and the potassium ones open so they leave the membrane, making it more neg. and repolarizing it begins
4) Return to normal permeability: potassium channels start to close once they get to -70 mV or normal resting potential, and sometimes its slow to close so hyperpolarization can occur
Axon Diameter and Propagation Speed
the more myelinated and the bigger the diameter of the axon, the faster the speed
Graded potential vs. Action potential
Graded: depolarizes/hyperpolarizes, no threshold value, amount of depolarization/hyperpolarization depends on. the intensity of stimulus, no refractory period
Action: always depolarizing, depolarization of threshold must occur in order for AP to begin, all-or-none principle, all stimuli that exceed threshold produce identical AP, refractory period occurs, occurs in only excitable membranes of specialized cells such as neurons and muscle cells
Excitatory Postsynaptic Potential (EPSPs)
graded depolarization of postsynaptic membrane caused by NT at the postsynaptic membrane, results from the opening of chemically gated ion channels in the plasma membrane, it’s a graded potential so EPSPs affects only the area immediately surrounding the synapse
Inhibitory Postsynaptic Potential (IPSPs)
graded hyperpolarization of the postsynaptic membrane, may open due to chemically gated potassium ion channels
Things to know about the spine
-Spinal cord itself is part of the CNS
-Spinal nerves are part of the PNS (there are 31 pairs)
dorsal root
posterior, and think SENSORY info going into the spinal cord to go up to the brain
basically stimulus info travels up a sensory neuron from the PNS and it goes through your spinal nerve into your spinal cord, and from then on it gets sent to the CNS for processing at the brainstem/brain
ventral root
anterior, think MOTOR neurons, and info coming from the brain down the spinal cord
essentially neurons bring down information from the CNS/brain and it goes through either somatic (voluntary movement like skeletal muscle contractions) or autonomic (involuntary movement like cardiac muscles, smooth muscle glands, and adipose tissue)
Locate the somatic and visceral nuclei of sensory and motor nuclei in the spinal cord AND Describe the function of each horn of gray matter
posterior horn: houses somatic (skin, muscles, and bone) and visceral (internal organs/structures) parts to it, these are are SENSORY nuclei
lateral horn: houses visceral motor nuclei (think autonomic NS)
anterior horn: houses somatic motor nuclei (think skeletal muscles)
white matter functions
has myelinated axons and each column tract contains bundles of axons that relay info up and down the spinal cord (ascending + descending tracts)
Ascending Tract
in white matter, carries info up to the brain, and this would be an example of it going through the dorsal root
Descending Tract
in white matter, carries info carries motor commands down the spinal cord, this would be an example of something going through the ventral root
it also controls/inhibits ascending pathway
Reflexes
automatic responses to stimuli coordinated within CNS, it’s part of the somatic nervous system and the only part of that system that’s involuntary
Reflexive arc
1) activation of stimulus of receptor
2) activation of sensory neuron
3) information processing goes to CNS
4) activation of motor neuron (reflex part)
5) response by a peripheral effector
Compare and contrast monosynaptic and polysynaptic reflex arc
POLYSNAPTIC:
1) polysynaptic reflexes are more complicated than monosynaptic reflexes
2) interneurons control more than one muscle group
3) involve EPSPs and IPSPs
Four Major Brain Regions
1) the cerebrum
2) the cerebellum
3) the diencephalon
4) the brainstem
Stuff to to know about the brain/brainstem
-part of the CNS
-there are 12 pairs of cranial nerves
-your brainstem encompasses the midbrain, pons, and medulla oblongata
-thalamus on top, hypothalamus on bottom
-cerebrum on top, cerebellum on bottom
in the cerebral hemispheres you have gyri, suculi, and fissures
Gyri: cerebral cortex forms a layer of rounded elevations used to increase surface area
Sulci: shallow grooves that separate the gryi
Fissures: deeper grooves that separate the larger brain regions
functions of Cerebral Spinal Fluid (CSF):
1) supporting the brain
2) cushioning delicate neutral structures
3) transporting nutrients, chemical messengers, and wastes
explain the formation and circulation of CSF
ependymal cells make CSF and they make this in the choroid plexus (which is in the third ventricle) produces and maintains CSF.
1) CSF is produced in the choroid plexus in the third ventricle by ependymal cells (CNS)
2) it goes through your cerebral aquaduct
3) then to your central canal
4) and finally your arachnoid granulations
Blood-Brain Barrier (BBB)
it’s in the CNS and it isolates CNS neural tissue from general circulation; its’ forced by a network of tight junctions, and it’s controlled by astrocytes who release chemicals that control the permeability of the endothelium (what makes up the BBB)
Medulla Oblongata
ok so it’s part of the brainstem and it’s right underneath the pons; main f(x)s: keeping you alive, but it contains nuclei that control visceral functions + it coordinates complex autonomic reflexes reflexes (swallowing, coughing, and vomiting)
autonomic reflexes include: cardiovascular center, respiratory rhythm center, and digestive center
Midbrain
it’s above the medulla oblongata and pons; it’s responsible for regulating auditory (inferior) and visual (superior) reflexes, and it controls alertness
Diencephalon is the made up of what?
Thalamus and Hypothalamus
Thalamus
relays and processes CONSCIOUS sensory information, and it works with the limbic system as well when it filters sensory information
anatomically it’s above the hypothalamus
Hypothalamus
autonomic functions and visceral control, UNCONSCIOUS information, think circadian rhythm, regulating endocrine functions, and regulating body temperature
Pons
relays sensory info to cerebellum and thalamus; also subconscious somatic and visceral motor centers
Cerebellum
coordinates learned + reflexive patterns of muscular activity at the subconscious level
1) adjusts postural muscles of the body
2) program + fine tune movements at conscious/unconscious levels
Limbic System
mainly deals w/emotion, motivation, and memory
it also encompasses amygdaloid body, hippocampus, and thalamus + hypothalamus
f(x)s in detail: 1) establish emotional states
2) link conscious, intellectual functions of cerebral cortex w/unconscious and automatic functions of brainstem
3) facilitate memory storage and retrieval
Amygdaloid body
interface between the limbic system, cerebrum, and sensory systems, and regulates flight-or-flight responses
Hippocampus
important for learning and facilitates storage and retrieval of long-term memories
Cerebrum
processes sensory and motor info, think conscious thought and all intellectual functions
Association fibers
interconnect areas of cerebral cortex
commissural fibers
interconnect cerebral hemispheres
projection fibers
link cerebral cortex to diencephalon, brainstem, cerebellum, and spinal cord
Basal Nuclei
processes sensory information and coordinates motor commands outside of conscious awareness
basal nuclei coordinates the movement, sequence of the movement and then the cerebellum adds skill to the movement and fine tunes it
Lobes of the cerebral cortex:
frontal lobe, parietal lobe, occipital love, and temporal love
Frontal lobe
primary motor cortex and premotor cortex
Parietal Lobe
primary somatosensory cortex(touch, pain, pressure, vibration, temperature), somatosensory association cortex (identifies what it is and coordinates motor response)
Occipital Lobe
visual association area and visual cortex
Temporal Lobe
auditory cortex, auditory association area, and olfactory cortex (smell)
Broca’s area
speech production area (near motor cortex)
Wernicke’s area
language comprehension area (near auditory cortex)
