BIO 241 : Test 5 : Neuron, Central Nervous System

central nervous system (CNS)
One of the two divisions of the nervous system. Includes the brain and the spinal cord.
peripheral nervous system (PNS)
One of the two divisions of the nervous system. The XXX is everything outside of the central nervous system. So all nervous system material that isn't in the brain and spinal cord . Has two sub-groups: afferent division and the efferent division
2 subdivisions of the PNS
afferent division and the efferent division
Afferent division
One of the two divisions of the Peripheral Nervous System. Takes messages IN to the central nervous system (primarily sensory input).
Efferent division
One of the two divisions of the Peripheral Nervous System. Takes messages OUT from the central nervous system to the peripheral nervous system. It's called the "motor division" since its info causes movement and is translated along motor units. Has two sub-divisions: somatic nervous system and the autonomic nervous system.
2 subdivisions of the efferent division:
somatic nervous system and the autonomic nervous system.
Somatic Nervous System
One of the two divisions of the efferent system. All of the nervous system under voluntary control. The system that stimulates the skeletal muscles (voluntary). Some involuntary responses are included (reflexes).
autonomic nervous system
One of the two divisions of the efferent system. All involuntary. Controls organs, smooth muscle, cardiac muscle, glands, adipose tissue. It has two subdivisions: sympathetic and parasympathetic.
function (neuron calculation - 3)
sensory (afferent) neurons
motor (efferent) neurons
interneuron (association) neuron
Sensory neuron (afferent system)
XXX system. Type of neuron?

Carry impulses IN from outside the CNS to the CNS. Made up of unipolar neurons. Action potential moves from the synaptic terminal (receptive endings), past the cell body to the central process and into the Central Nervous System.
motor neurons (efferent system)
XXX system. Type of neurons?

Take signals from the CNS to the organs that do the "work."
(aka association neurons )
Are IN the CNS. Pass info from one neuron to another. There are a lot of these in the CNS. "go between"
Sensory (afferent) neuron (unipolar)
motor neuron
interneurons (association neuron)
neuron classification by structure
Multipolar (nerve cell type)
One axon and multiple dendrites i.e. multiple processes comes out of their cell body. An example would be motor neurons in the efferent system and interneurons inside the CNS
Bi - two processes coming out of the cell body: one dendrite, one axon. Sensory neurons - afferent system. These are only found in the eye, ear and nose.
Uni - one process coming out of the cell body. It becomes an axon. Sensory neurons - afferent system. They relay info to the CNS. Their cell bodies are OUTSIDE the CNS.
The main cells of the nervous system - they do the actual work of moving signals / messages. They don't divide (reproduce). They live a long time. They are constantly making proteins to repair themselves and are making neurotransmitters (i.e. "metabolically active")
4 kinds of glial cells (neuroglia) in CNS
ependymal cells, astrocytes, oligodendrocytes, microglia
2 types of glial cells found in the PNS
satellite cells and schwann cells
Ependymal cells
1 of 4 types of neuroglia. They help make and circulate cerebrospinal fluid which is key for protecting the brain and spinal cord. They line the brain and the spinal cord.
1 of 4 types of neuroglia. Very diverse set of cells that scientists keep finding do more jobs. One of their jobs is keeping the blood-brain-barrier so substances in the blood do not get into the brain. Recycle neurotransmitters. Make scar tissue. Regulate concentrations of ions and gasses. Provide structural support.
1 of 4 types of neuroglia. "Myelinate CNS axons" (meaning they provide the myelin that protects the axons of CNS nerves. Also provide structure
1 of 4 types of neuroglia. Macrophages (phagocytic) cells of the CNS. They keep it clean ! They remove debris, waste products and harmful substances.
Ependymal cells
Neuron Cell Body
"Soma." Made up of the perikaryon (cytoplasm around the nucleus) and the nucleus. Along with the dendrites, it is the portion of the nerve cell that receives signals from other neurons. Usually the XXX is located in the CNS (brain or spinal cord) except for unipolar (sensory) neurons that have their cell bodies outside the CNS.
Chemically-gated Channels
"Ligand gated" channels. The presence of a chemical at the channel gate causes it to open. Ex: Acetylcholine causing the ion channels to open at the motor end plate.
Voltage-gated channels (mV triggers? define.)
Open in response to a change in electrical voltage level.
Ex: Na+ gate: At the normal resting potential of -70mV it stays closed. At -60mV it opens. At +30mV it is closed again.
Mechanically-gated channels
Open in response to pressure.
Ex: receptors in the ear that open in response to the pressure in the fluid of the inner ear.
Ex: touch receptors that open in response to mechanical pressure from touch.
The potential of the membrane becomes LESS negative. When XXX happens, the normal resting potential of -70mV becomes -60mV and much higher until it actually becomes positive. It must reach a threshold potential to start the domino effect of action potential.
The potential of the membrane becomes MORE negative (more than -70mV). This acts as an inhibitor. Since the threshold stays the same at approx. -60mV, any XXX forces a stronger signal to start the actual potential.
Chemically-gated Channels
Voltage-gated channel
Mechanically-gated channels
cell body (soma)
axon hillock
synaptic terminal (exact name of neuron part used)
the secretory region on the telodendria
axon collateral
The axons of some neurons branch to form XXX that can be divided into a number of smaller branches called telodendria. Along these the bifurcated impulse travels simultaneously to signal more than one other cell.
chemical synapse
overall, this is a picture of what?
synaptic cleft
synaptic vesicles
myelin sheath
insulating sheath. Formed by Schwann cells (PNS) or oligodendrocytes (CNS)
outermost portion of Schwann cells with nucleus and bulk of cytoplasm
plasma membrane
edge of the cell. Resting membrane potential happens here.
nodes of Ranvier
gap in myelin sheath between individual myelinating cells
myelin sheath
Action Potential Phases: Na K (Na+, K+ channel activity: 5 steps) 1
Action Potential Phases: Na K (Na+, K+ channel activity: 5 steps) 2
Action Potential Phases: Na K (Na+, K+ channel activity: 5 steps) 3
Action Potential Phases: Na K (Na+, K+ channel activity: 5 steps) 4
Action Potential Phases: Na K (Na+, K+ channel activity: 5 steps) 5
overview of action potential phases
periosteal layer - dura mater
meningeal layer - dura mater
arachnoid mater
pia mater
dura mater (tough mother)
arachnoid mater (spider mother)
pia mater (small mother)
How are the meninges different in the spinal cord?
only one meningeal layer
falx cerebri
falx cerebelli
tentorium cerebelli
tentorium cerebelli
falx cerebri
falx cerebelli
dural septa (1. falx cerebri 12-to-6-for-cerebrum. 2. falx cerebelli 12-to-6-on-cerebellum. 3. tentorium cerebelli tent-over-cerebellum)
nuclei (in the context of the brain)
gray matter
neuronal cell bodies (what makes up the XX XXX ?)
white matter
myelinated axons (what part of the brain and spinal cord is this?)
cerebellum (white and gray matter)
brain stem (white and gray matter)
spinal cord (white and gray)
commisural fibers (corpus callosum) (1 of 3 white matter fiber tracts)
projection fibers (1 of 3 white matter fiber tracts)
(type of fibers)
association fibers (1 of 3 white matter fiber tracts)
association fibers (1 of 3 white matter fiber tracts)
commissural fibers (corpus callosum) (1 of 3 white matter fiber tracts)
projection fibers (1 of 3 white matter fiber tracts)
decussation of pyramids
cerebrum (function)
cerebellum (function)
cerebrum (location)
diencephanlon (location)
cerebellum (location)
brain stem (location)
diencephalon (3 in group)
1. Thalamus
2. Hypothalamus
3. Epithalamus
brain stem (3 in group)
1. midbrain
2. pons
3. medulla oblongota
gyrus (definition)
ridge of tissue
sulcus (definition) (not a LARGE groove)
groove in tissue
fissure (definition)
a DEEP sulcus (i.e. a deep groove in the tissue)
gyrus (location)
sulcus (location)
fissure (location)
frontal lobe (location)
central sulcus (location)
parietal lobe (location)
lateral sulcus (location)
occipital lobe (location)
temporal lobe (location)
transverse cerebral fissure (location)
thalamus (function)
relay station for cerebral cortex
hypothalamus (function)
emotions, autonomic control, homeostasis, sleep, endocrine system regulation
(part of brain controlling)
midbrain (function)
visual & auditory reflexes, motor control (part of brain controlling these)
pons (function)
mostly nerve tracts between brain and spinal cord
medulla oblongata (function)
cardiovascular, respiratory regulation
primary somatosensory (greek soma = body. sensory = the senses) cortex and postcentral gyrus
primary motor cortex and precentral gyrus
left hemisphere
seems to be specialized in reading, writing,
speaking, logic, math, etc. Performs: analytical tasks, language-based skills (speaking, writing, reading, etc.) and logical decision making. People that are XXX
brain dominant have a tendency to be more scientific.
right hemisphere
seems to be more specialized in interpreting sensory information, determining spatial relationships, interpreting emotional responses, etc. Performs analysis of sensory
information and comprehending three-dimensional relationships. XXX brain dominant people are more artistic.
cerebral cortex
Primitive emotions are spontaneous (requiring no conscious thought). It is this characteristic that differentiates them from the higher emotional states (i.e., jealousy, humor, etc.) produced in the XXX . XXX is convoluted to increase its gray matter capacity. This surface is marked by fissures (deep valleys), sulci (shallow grooves), and gyri (ridges) which delineate it into various regions.
The XXX lies approximately in the center of the brain. More specifically, the XXX is inferior to the thalamus. Because of its central location, the XXX connects the lower brain stem to brain's upper regions. Therefore, it contains motor tracts that
go to the cerebellum and sensory tracts that go to the thalamus. These tracts facilitate the XXX's function which is RELAYING information to the proper brain region.
pineal gland
This structure is thought to act like a biological clock by melatonin (controls wake and sleep patterns).
central sulcus
Separates the parietal lobe from the frontal lobe. The
frontal lobe is anterior to it (in front of it), while the parietal lobe is posterior (behind it).
longitudinal (cerebral) fissure
divides the cerebrum into two regions called cerebral hemispheres. These regions are connected by a bridgelike
structure called the corpus callosum.
closed (voltage-gated Na+ channel)
opened (voltage-gated Na+ channel)
inactivated (voltage-gated Na+ channel)
Resting Membrane Potential DEPENDS ON
K+ leakage channels and Na+ leakage channels ("membrane ion permeability").
ion conentration gradients
what MAINTAINS the RMP ?
Na+ / K+ membrane pump
is the plasma membrane more permeable to K+ or Na+ ?
K+ predominates inside the cells.
Na+ predominates outside the cell
[explain plasma membrane permeability]
XX predominates inside the cell.
XX predominates outside the cell.
Leakeage channels (passive transport) let K+ diffuse OUT of the cell. Membrane less permeable to Na+ but some do diffuse into the cell.
what does the Na+ / K+ pump do?
hyperpolarization vs. depolarization
If XXX crosses the threshold potential (and voltage-gated channels are nearby) it becomes the self-propogating action potential.
graded potential
action potential
where on the neuron does the action potential occur?
conducting region: axon and telodendria.
(axon hillock is where the XXX starts!)
where on the neuron does the graded potential happen?
The cell bodies. The receptive region of the neuron (dendrite and cell body). You don't have voltage-gated channels on the cell bodies or dendrites so you CAN'T get an action potential there, so you get XXX here.
saltatory conduction
jump from node to node i.e. myelinated
FAST .. myelin sheath slows decay of membrane potential
continuous conduction
(there is no "nonsaltatory")
unmyelinated. Propagation relatively SLOW due to time for ion flow and channel opening
unmyelinated (continuous conduction)
myelinated (saltatory)
How is myelin formed in the peripheral nervous system?
Schwann cells
How is myelin formed in the central nervous system?
electrical synapse
type of synapse is?
chemical synapse
presynaptic neuron
postsynaptic neuron
chemical synapse (5 steps) 1
chemical synapse (5 steps) 2
chemical synapse (5 steps) 3
chemical synapse (5 steps) 4
chemical synapse (5 steps) 5
coup vs. contrecoup
coup vs. contrecoup
CVA (cerebrovascular accident i.e. Stroke)
TIA (transient ischemic attack)
refers to uncoordinated movements, such as walking.
an impairment of language ability
ACh Acetylcholine)
excitatory (type of neurotransmitter)
cause depolarization
(what type of neurotransmitter causes depolarization?)
cause hyperpolarization
ventral (anterior) root (location)
ventral (anterior) root
What part of spinal cord?
motor (motor = efferent = effectors) neurons
ventral (anterior) horn (location)
ventral (anterior) horn (function)
(which part of spinal cord?)

somatic (somatic = voluntary) MOTOR neurons and some interneurons
dorsal (posterior) root (location)
dorsal (posterior) root (function)
sensory (sensory = afferent = receptor) neurons

(Found in what part of the spinal cord?)
dorsal (posterior) horn (location)
dorsal (posterior) horn (function)
somatic (somatic = voluntary) SENSORY interneurons
and visceral (visceral = autonomic = involuntary) SENSORY interneurons
spinal nerves (location)
spinal nerves (function)
dorsal root + ventral root = merge together to form a XXX before exiting spinal column
white matter (spinal cord location)
white matter (spinal cord function)
myelinated axons (what part of the spinal cord do these make up?)
gray matter(spinal cord location)
gray matter (spinal cord function)
neuronal cell bodies (what part of the spinal cord are neuronal cell bodies?)
What is the dorsal root ganglion?
= autonomic = involuntary
Sort of like a XXX reaction - you don't control it
= voluntary
(like SMACK) I control the slap !
afferent (unipolar neuron - structural)
= sensory = receptor
TYPE of neuron?
= motor = effector
blood-brain barrier
What functions does CSF serve?
How do the ion concentrations in CSF differ from blood plasma, and why?
csf circulation 1
csf circulation 2
csf circulation 3
csf circulation 4
dural (venous) sinus
formed by the separation of periosteal and meningeal layers. Drain blood and CSF from the brain. Arachnoid villi protrude into them.
dural venous sinus (location)
decussation of pyramids
the axons cross to the ___ side at the decussation of the pyramids
cross to the contralateral side
What are the cervical and lumbar
Where does the spinal cord actually terminate?
What is the cauda equina?
It is below L1 or L2 (where the spinal cord ends) to the sacrum (S2) are spinal nerve roots enclosed in dura and arachnoid mater. The spinal nerves are free floating in fluid. "horse tail"
What is the conus medullaris? and where is it located?
The "medullary cone" (also known as XXX) is the terminal end of the spinal cord. It occurs near lumbar vertebral levels 1 (L1) and 2 (L2).
denticulate ligaments
Explain the functions of the denticulate ligaments.
These paired ligaments run along the length of the spinal cord. They extend from the pia mater through the arachnoid mater to the dura mater. They PREVENT LATERAL movement. At the foremen magnum and the coccygeal ligament, they prevent LONGITUDINAL movement.
Explain the functions of the filum terminale.
It is a slender strand of fibrous tissue which extends from the inferior tip of the conus medullaris. It continues along the length of the vertebral canal as far as the second sacral vertebra. It provides LONGITUDINAL support to the spinal cord as a component of the coccygeal ligament.
Where is a lumbar spinal tap ("lumbar puncture" or "spinal tap") done? Why here?
between L4 and L5
Why is the lumbar puncture done where it is?
Less likely to damage the spinal nerves because they are floating there below the end of the spinal cord at L1 or L2
Where is an epidural injection made?
loss of motor function
loss of sensation
flaccid paralysis (spinal cord trauma)
spastic paralysis (spinal cord trauma)
paraplegia (spinal cord transection)
quadriplegia (spinal cord transection)
endoneurium (function)
surrounds the individual axons.
endoneurium (location)
perineurium (function)
surrounds the fascicles (bundles of axons)
perineurium (location)
epineurium (function)
surrounds the "nerve entire"
epineurium (location)
myelin (location)
fascicle (location)
node of ranvier (longitudinal slide)
myelin (on cross section)
axon (on cross section)
3 types of fibers in the brain
association fibers (connect regions of the same hemisphere)
commissural fibers (connect regions of the two hemispheres)
projection fibers (connect the lobe to the spinal cord)
cerebral cortex (location)
This is the gray area of the brain. It covers the cerebrum and cerebellum. "The cerebellum and the cerebrum have external gray matter layer called the XXX."
cerebral cortex (function)
cerebrum (location)
1 of 4 major regions of the brain (xxx, cerebellum, diencephalon, brain stem). the major part of the brain. divided into right and left hemispheres.
cerebrum (function)
midbrain (location)
midbrain (function)
on the brain stem. visual and auditory REFLEXES. Motor control.
pons (location)
medulla (location) (i.e. medulla oblongota)
medulla (function) (i.e. medulla oblongota)
primary motor cortex (location)
primary motor cortex (function)
precise motor control
premotor cortex (location)
premotor cortex (function)
primary sensory (somatosensory) cortex (location)
primary sensory (somatosensory) cortex (function)
primary visual cortex (location)
primary visual cortex (function)
detect and localize sensation (visual)
primary auditory cortex (location)
primary auditory cortex (function)
detect and localize sensation (hearing)
association cortices (function)
INTERPRET sensations in the context of PAST experience
corpus callosum (location)
corpus callosum (function)
Wide, flat bundle of neural fibers beneath the cortex at the longitudinal fissure. It connects the left and right cerebral hemispheres and facilitates interhemispheric communication. It is the largest white matter structure in the brain.
basal nuclei (location)
masses of gray matter that lie deep to the floor of the lateral ventricle. Embedded in the white matter of the cerebrum.
basal nuclei (function)
(what part of brain does ...) background patterns of movement involved in voluntary motor activities. Ex: control muscles that determine the background position fo the trunk or limbs or direct rhythymic cycles of activities such as walking or running.
thalamus (location)
thalamus (function)
relay station for cerebral cortex
hypothalamus (location)
hypothalamus (function)
autonomic control
endocrine system regulation
pituitary gland (location)
about the size of a pea and weighing 0.5 grams (0.018 oz) in humans. It is not a part of the brain. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity (sella turcica) covered by a dural fold
pituitary gland (function)
synthesizes and secretes important endocrine hormones (HGH, oxytocin, etc.)
infundibulum (location)
infundibulum (function)
A small outgrowth of the ventral wall of the embryo brain from which the pars nervosa (the posterior lobe) of the pituitary gland develops is also called the XXX. (Another name for this structure is the pituitary stalk.) Connection between the hypothalamus and the posterior pituitary.
pineal gland (location)
pineal gland (function)
produces melatonin. Also known as the epithalamus
optic chiasm (location)
optic chiasm (function)
part of the brain where the optic nerves cross (partially). At bottom of the brain immediately below the hypothalamus
lateral ventricles (location)
lateral ventricles (function)
buoyancy - brain is supended in CSF.
allows CSF to circulate.
arbor vitae (location)
white tree in the middle of the cerebellum
brain stem (location)
brain stem (function)
most basic, automatic survival behaviors
(what part of brain controls these?)
pons (location)
multimodal (location)
multimodal (function)
infundibulum (location)
pons (location)
corpus callosum (location)
2 together are more likely to have an action potential
cancel each other out - no action potential
EPSP (Excitatory Post-Synaptic Potentials)
IPSP (Inhibitory Post-Synaptic Potentials)
EPSP (Excitatory Post-Synaptic Potentials)
IPSP (Inhibitory Post-Synaptic Potentials)
stength of graded potential depends on
temporal summation (integration)
spatial summation (integration)