BIOL 252 Exam 1

What is an electrical potential and how can it produce an electrical current?

Electrical gradient - separation of electrical charges across the plasma membrane Particles are charged and have potential (voltage)

What is the relationship between the electrical and chemical gradient for K+?

Electrical gradient counteracts chemical gradient

How does an electrical signal travel through a chemical synapse?

Electrical signal -> chemical signal -> electrical signal 1. Action potential (sodium ions) travels through presynaptic neuron 2. Depolarization leads to opening of Ca++ voltage-gated channels in presynaptic terminal, allowing calcium ions to flow into presynaptic cell 3. Vesicle fusion with presynaptic neuron membrane and release of neurotransmitter into synaptic cleft 4. Neurotransmitter binds to postsynaptic receptor; ligand-receptor binding causes an effect (ex: receptor allows ions to pass) 5. Depolarization or hyperpolarization of post synaptic membrane because of the opening of ion channels 6. Cessation of signal: neurotransmitter is removed from its receptors

What drives ion movement?

Electrochemical gradient

True/False As the stomach extends during lunch, stretch receptors in the stomach wall send neural signals to the brain via the autonomic nervous system.

False

True/False The direction of ion flow (into or out of the cell) depends on whether the channel is open or closed

False

Nissl bodies are responsible for the gray color of the gray matter, regions in the CNS that are highly enriched in cell bodies. Can you hypothesize why Nissl bodies exist in neurons and not in other cells?

Neurons constantly send electrical signals and need proteins that the Nissl bodies make.

At a resting state, which gates are open and closed?

Na+ activation: closed Na+ inactivation: open K+: closed

After reaching a threshold upon depolarization, which gates are fast and slow?

Na+ activation: fast gate Na+ inactivation and K+: slow gates

Absolute refractory period

Na+ channels have not yet reset to resting positions -new AP cannot be generated

Why do action potentials not die out as they progress?

Na+ voltage-gated channels keep opening

What is an IPSP?

Needed for regulation. Results in hyperpolarization and makes it harder to reach the threshold. (membrane may become more permeable to K+ and Cl- ions)

What is an example of a visceral sensory input that will go to cerebral cortex because it's important to make a good decision?

Needing to pee

Would you expect the electrical membrane potential that counteracts the K+ chemical gradient to be negative or positive?

Negative K+ attracted to negative

What will happen if the neurotransmitter, after being released from the synaptic vesicles, will not be absorbed or destroyed?

Neurotransmitter will stay in synaptic cleft and increase in concentration

Where are mechanically gated channels found?

Sensory reecptors

Sensory and motor pathways are ascending and descending?

Sensory: ascending Motor: descending

When Bob first had corrective braces put on his teeth, the pressure and tension were very uncomfortable. Now, however, he barely notices his braces. Why?

Since the pressure is constant, his sensory receptors have adapted

After a stroke a patient complains about lack of sensitivity in her right hand. The stroke most likely affected:

Somatosensory cortex in her left parietal lobe

Relative refractory period

Some Na+ channels have reset to their resting positions

How can EPSPs or IPSPs induce an action potential?

Spatial summation: postsynaptic neuron stimulated by large number of terminals at same time Temporal summation: presynaptic neurons transmit impulses in rapid-fire order -AP will only be generated in axon hillock

How does it "deliver the message" of stretch?

Stretching stretches the intrafusal fibers in muscle spindles, which opens mechanically gated ion channels in primary and secondary afferents. Primary and secondary afferents transmit action potential to spinal cord

The autonomic nervous system (ANS) is sometimes called the visceral nervous system, as it controls mostly visceral effectors. Can you think of non-visceral effectors that are controlled by the ANS?

Sweat glands

What is an example of an autonomic motor division tissue that lies outside the body?

Sweat glands

What are synergists and antagonists?

Synergists: fix muscles in place to help cancel out extra motion from antagonist Antagonist: inhibit movement

What is the diencephalon composed of?

Thalamus, Hypothalamus, Epithalamus (pineal gland - melatonin)

True or false? The parasympathetic division is typically an inhibitory system while the sympathetic division is an excitatory one

True

True/False Most neurons have a single axon

True

True/False Only Na+ voltage-gated channels respond to a membrane potential of -55 mV

True

True/False Upon closing of the K+ gated channels, Na+ and K+ concentrations in the ICF and the ECF are similar to the original concentrations prior to the initiation of the action potential

True

True/False- The chemical gradient drives K+ from the cytosol out to the ECF

True

True/False Accumulation of CSF would lead to an over-sized brain organ.

True -like filling a room with more and more water

True or false? Explain All reflexes have an integration center (a CNS component), even monosynaptic reflexes

True. They must all go to the CNS to integrate the stimulus.

The trigger zone, the site where the cation potential initiates, is found at the

axon hillock

Where can action potentials be generated and propagated?

axon membrane neurons and muscles

tracts

groups of nerve fibers going towards and coming from the brain; responsible for carrying sensory and motor stimuli to and from the periphery

corpus callosum

largest group of commissural fibers in the brain; connects the right and left cerebral

Which system increases heart rate?

sympathetic ANS -no cerebral cortex -emotions from amygdala -> signals to hypothalamus -> cardiac center in medulla oblongata -> heart

Channels

transmembrane proteins that allow certain substances to cross the membrane and pass into or out of the cell

Resting membrane potential is maintained by the Na+/K+ ATPase, which brings __________

two potassium ions into the cytosol and three sodium ions into the extracellular fluid

Effect of the neurotransmitter on the postsynaptic membrane depends on what?

type of receptor (excitatory or inhibitory), not nature of neurotransmitter

Modality

type of stimulus or the sensation it produces

prefrontal cortex

us! -does not directly get sensory input - gets input from other parts of brain -working (short term) memory and emotions

hypothalamus

visceral control center -link between nervous and endocrine systems -controls drives -nuclei are both neurons and glands (secrete neurotransmitters and hormones) -body temperature -ANS -CEO of ANS

Bilateral damage to the reticular formation of the midbrain may lead to

coma or death

gyri

elevated ridges between sulci that increase surface area of brain

Location

encoded by which nerve fibers are issuing signals to the brain

Axon Terminal/Synaptic Knob

end of axon that communicates with target cell

Cerebellum

"autopilot" of brain, movement plants

hydrocephalus

"water on the brain," excess CSF -treat by draining excess actively to other parts of body

What is the reversal potential of K+ in neurons?

-88 mV

Medulla oblongata

-ANS reflex -finetune

If someone had Broca's area damaged, the result will be

-Broca's aphasia unintelligible speech (no plan, but there is recognition)

Astrocytes

-SUPPORT and brace neurons -control chemical environment -most numerous and largest neuroglia in CNS -anchors neurons and blood vessels in place using end-feet -regulates extracellular environment of the brain -assisting in formation of blood brain barrier -repairing damaged brain tissue

limbic system

-amygdala: emotion and memory -hippocampus: learning and memory

What happens when one is over-responsive?

-autism -no way to filter or process overwhelms -> body moves away from stimuli -typically issue in cerebral cortex -typically issue about processing and sensing

Ependymal cells

-ciliated epithelial cells lining central cavities of brain and spinal column -form permeable barrier between CSF and nervous tissue -beating cilia helps circulate the CSF

How is apraxia treated?

-compensate with other muscles to make better speech

premotor cortex/motor association area

-controls learned, repetitious, or patterned motor skills -coordinates plans

Function of basal nuclei?

-determine onset and cessation of intentionial movements -better motor plan -coordinate control of antagonistic muscle pairs (biceps vs. triceps)

How can neurotransmitters be removed from its receptors? (termination of synaptic transmission)

-diffusion away -degradation of neurotransmitter by enzyme in synaptic cleft (recycled back to synaptic neuron sometimes) -reuptake into presynaptic terminal

Phasic receptors

-fast adapting receptors (getting used to shirt you are wearing) -notify on change (start and stop)

Serious damage to medulla oblongata results in what?

-functioning, but no regulation or finetuning -"brain death"

Ways to report different intensities to the CNS?

-greater frequency of APs -increase number of neurons firing -different sensory receptors with different thresholds

How does the BBB function?

-like a brick wall -higher concentration of tie junctions (like cement) in between capillaries -cells must be hydrophobic to go through cell

How to hyperpolarize a membrane?

-make potassium leave by using ligand gated channel -let chloride into cell by using ligand gated channel

Wernicke's aphasia

-make speech plan, not aware of how much they understand -will try to cheat themselves -gibberish -throw words together for possible answers

reticular formation

-nuclei scattered along brain stem -cortex alert and awake -filters out "background" sensory input

What will happen if the cells of the substantia nigra degrade?

-overactive movement (lose fine control - tremors), resulting in diseases such as Parkinson's

What is the function of the BBB?

-prevent capillaries from leaking into brain

apraxia

-problem with executors (speech receptors) -similar to Broca's -some primary motor cortex neurons damaged and cannot send APs to skeletal muscles

Wernicke's area

-recognition of spoken and written language -usually found in left hemisphere

thalamus

-sensory relay center (post office) -sensual afferent impulses converge and synapse -impulses sorted out, edited (accelerated with EPSPs), relayed as group -almost all inputs ascending to cerebral cortex pass through thalamus (not smell)

brain stem

-structural framework, hosting neural fibers -automatic system

Midbrain

-substantia nigra: inhibition of basal nuclei

The membrane potential does not go beyond 30 mV due to the closing of the?

Inactivation gate of sodium channels

With regards to the five components addressed in question #3, identify those components in the reflex arc, which is depicted in Figure 14.1

1. Sensory signals from the viscera and skin are sent by afferent sensory neurons to the brain or spinal cord. 2. Stimuli integrated by CNS. 3. Motor impulses from CNS sent out via efferent motor neurons in cranial and spinal nerves, which usually lead to ganglia in PNS (autonomic ganglia). 4. Autonomic ganglia send impulses via other efferent motor neurons to various target organs, where they trigger a motor response.

Explain the process of an action potential being generated.

1. channels closed (Na+ inactivation open) - resting membrane potential (-70 mV) 2. Stimulus -threshold reached (-55 mV) -positive feedback loop: ions stimulate more channels to allow more sodium to enter -Na+ activation gates open -depolarization 3. Repolarization -Na+ inactivation gates close slowly -K+ open 4. Hyperpolarization/undershoot Na+ activation gates close K+ open

Define the five components of a reflex arc

1. receptors: sensory, detect stimulus 2. afferent neurons: lead to CNS 3. interneurons in CNS 4. efferent neurons: carry motor signal away from CNS 5. motor effector that carries out motor response

What distinguishes a neuron from a neuroglia cell?

A neuron is a nerve cell that transmits electrical and chemical information around the body. It has an axon and dendrites extending from the soma. A neuroglia cell is a tissue that deals with connectivity in the nervous system. Does not have axon or dendrites and supports the neurons by making myelin sheath, anchoring neurons, become phagocytes, and release fluid

Which of the following events does not occur when the action potential is propagated along the axon? A. As potassium ion channels activate, an action potential is triggered and spreads positive charges down the axon. B. The current continues to move down the axon, and the process repeats C. The next section of the axolemma depolarizes to threshold and fires an action potential as the previous section of the axolemma repolarizes. D. The axolemma depolarizes to threshold as a result of local potentials.

A.

Which part of the nervous system is responsible for slowing down the heart beat rate?

ANS

Primary active transport

ATP is expended to move a substance against its concentration gradient using a protein pump (ex: sodium-potassium pump)

What type of potential is generated in the alpha motor neuron that innervates the quadriceps?

Action potential.

When responding to a stimulus, what type of potential is generated in the alpha motor neuron that innervates the hamstrings?

Action potential.

What are differences between local potentials and action potentials?

Action potentials: -not proportional to stimulus size -do not act locally -do not weaken with distance -do not spread in both directions -do not take place in many types of cells (ONLY in axon membrane neurons and muscles)

What are the five components of the visceral reflex arc (and for that matter, of any reflex arc)?

Afferent sensory neurons -> brain/spinal cord -> CNS -> efferent motor neurons -> autonomic ganglia

Carriers

Integral proteins that bind and directly transport substances into and out of the cell

What induces the formation of BBB?

Astrocytes and pericytes

What does multiple sclerosis do?

Attacks oligodendrocytes, losing myelin sheath in CNS -demyelinated axons don't have voltage-gated channels underneath the sheath -local potential dies out before reaching axon terminal

The ANS is sometimes called the "fine-tuning system". How does this definition concur with the following statement- "Visceral effectors do not depend on the autonomic system to function"? In other words, how is the somatic and autonomic system differ with regards to their effect on the target organs?

Autonomic motor neurons do not directly innervate their target cells. First, the initial efferent neuron (preganglionic neuron) is involved, which synapses onto the postganglionic neuron, within an autonomic ganglion in the PNS.

What are the 3 different synapses that a presynaptic neuron can form with a postsynaptic neuron?

Axodendritic synapse: interact with dendrites Axosomatic synapses: interact with soma Axoaxonic synapses: interact with axon

What will happen if we stimulate an axon in the middle?

C. Action potential will propagate to both sides -channels on left, towards soma, are not in absolute refractory period -once AP reaches axon hillock, stops

Sound is received in the inner ear via cells that are called hair cells. Sound waves arriving to the inner ear cause waves in the inner ear fluids. The hair cells move their "hairs" (which are actually ion channels) upon being hit by the fluid waves. As a result, the hairs bend and open potassium gated channels, allowing potassium ion to flow into the cells, later to trigger a neural signal that reaches the brain The "hairs" of the hair cells act as _______ a. ligand-gated channels b. non-gated (aka leak) channels c. mechanically-gated channels d. voltage-gated channels

C. mechanically-gated channels

Ependymal cell

CNS -circulate CSF -line cavities -cilia circulate fluid around brain and spinal cord -some secrete this fluid

Microglial cell

CNS phagocyte -"immune cells" of the CNS

Oligodendrocytes

CNS; myelinate axons

What facilitates the transport of information from the presynaptic neuron to the postsynaptic neuron in a chemical synapse?

Calcium ion channels

How does a graded potential spread locally?

Cations move towards a negative charge Site next to original depolarization event also depolarizes, creating another graded channels Dies out eventually

In two separate experiments, researchers increase the sodium concentrations in the ECF. In cell #1 they increase it more that they do in cell #2. Then, they stimulate the sodium ligand gated channels to open up Will the local membrane potentials in cell #1 be identical to the one in cell #2? Explain

Cell 1 has greater membrane potential. More sodium causes more ions to flow in at a given time, depolarizing the cell

If you had to choose only one type of synapse that would function in the entire nervous system, which synapse would you choose?

Chemical: more specific and regulated Electrical: faster, cannot stop signal

Influx of which of the following ions can cause an inhibitory postsynaptic potential (IPSP) to be produced?

Chloride ions

Describe 3 types of white matter

Commissural fibers: connect left and right cerebral hemispheres Projection fibers: connect cerebral cortex of one hemisphere with other areas of the same hemisphere, as well as with other parts of the brain and the spinal cord association fibers restricted to single hemisphere, connect gray matter of cortical gyri with one another

Fundamental purpose of sensory receptor?

Conduction - conversion of one form of energy to another -light/heat/touch/sound -> nerve signals (AP, in many cases low-level will create local)

Saltatory conduction

Conduction of action potentials by myelinated axons. The action potential appears to jump from one node of Ranvier to the next.

What is depolarization and hyperpolarization?

Depolarizing: making cell less polarized (closer to 0) Hyper: making cell more polarized (further from 0)

What is an example of a somatic motor division tissue that lies inside the body?

Diaphragm

Which of the following events is most likely to trigger an action potential? Hyperpolarization Inhibitory postsynaptic potential (IPSP) Excitatory postsynaptic potential (EPSP) Opening of potassium ion channels

EPSP

What is an EPSP?

EPSP is a local depolarization -a single EPSP cannot induce an action potential

True/False The simple stretch reflex employs mechanoreceptors known as Golgi tendon organs to detect the degree of stretch experienced by a muscle. The simple stretch reflex employs mechanoreceptors known as Golgi tendon organs to detect the degree of stretch experienced by a muscle.

False

True/False There are multiple dendrites in all neurons.

False

True/False- The chemical gradient drives Na+ from the cytosol out to the ECF

False

True/False- The membrane is equally permeable to all ions

False

True/False Jim got into an accident, which resulted in damage to his pre-motor cortex. As a result he cannot type anymore.

False. Can still type, lost ability to generate plan; can teach himself again because of synaptic plasticity depending on damage

True or false? Explain You are not aware (conscious) of a stimulus that triggered a reflex

False. Can become conscious of stimulus.

What facilitates the transport of information from the presynaptic neuron to the postsynaptic neuron in an electrical synapse?

Gap junctions with channels made of connexiones

Why do we need IPSPs?

Generated for negative sensory input that wins over multiple positive sensory inputs Make best choice to fire AP or not

What is the chemical gradient for Na+?

Higher concentration in ECF (outside) compared to cytosol (inside)

What is the chemical gradient for K+ in axons?

Higher concentration inside the cell (cytosol) than outside (ECF)

How does size matter for myelin sheaths and axons?

Larger diameter = lower resistance = faster impulse

What mechanisms maintain the resting membrane potential?

Leak channels and sodium-potassium pump

Difference between left and right hemisphere?

Left -control language, math, logic -thinking past and future -"adult" Right -visual spatial skills, emotion, artistic -present

How does a ligand (chemically) gated channel work?

Ligand triggers receptor to open up does not have to be ion specific

What serves as stimulus for AP generated at axon hillock?

Local potential coming from summation of EPSPs that diffuse

parasympathetic tone

Maintains smooth muscle tone in intestines Holds resting heart rate down to about 70 to 80 beats per minute

What is a reversal potential (aka Nernst potential or Equilibrium potential)?

Membrane potential at which there is 0 net flow of that particular ion from one side of the membrane to the other. What membrane potential would drive the ion back to its original location?

The _______ cells are capable of removing a blood clot from the brain

Microglia

What serves as the receptor in the reflex arc of the stretch reflex?

Muscle spindles

Summarize the differences between the sympathetic and the parasympathetic nervous systems, with regards to these factors: Neurotransmitters; Length of fibers; receptors

Neurotransmitters: AcH (pre) and NE/epinepherine/AcH (post) vs. AcH Length of fibers: long vs short Receptors: nicotinic (post) for both; adrenergic/muscarinic (sympathetic target) vs. muscarinic (parasympathetic target)

Summarize the differences between the somatic and the autonomic nervous systems, with regards to these factors: Neurotransmitters; Number of fibers; myelination; effectors; effect (excitatory vs inhibitory)

Neurotransmitters: only stimulate in somatic, stimulate or inhibit in autonomic Number of fibers: 1 vs 2 Effectors: skeletal vs cardiac/muscle cells and glands Effect: excitatory vs. both

A Na+ ligand gated channel is typically stimulated by acetylcholine (the ligand). Would you expect it to be stimulated by epinephrine as well?

No, because ligand-gated channels are protein specific

Is there mostly conscious sensation delivered to the CNS?

No, filtered out in brainstem -some don't require conscious awareness

Do sensory receptors sense?

No, the cerebral cortex senses

Does a single action potential move through the cell?

No. Formation of AP in one site generated AP in the next site, and so forth

Why does AP move only in one direction?

Not enough voltage-gated channels in soma

What are the mechanisms by which a stimulus can lead to hyperpolarization?

Potassium ion channels or chloride channels open

What neuroglial cells surround and support the cell bodies of neurons and have intertwined processes that link them with other parts of the neuron

Satellite cells

How do you explain the fact that the membrane potential drops below the original resting membrane potential (aka the hyperpolarization step- step # 5)?

The outflow of K+ continues until the membrane potential hyperpolarizes because the gates of the K+ channels are slow to close, allowing additional K+ ions to leak out of the cell.

Describe in two sentences each of the two division of the ANS

The sympathetic nervous system maintains homeostasis when the body is engaged in any type of physical work and mediates the body's visceral responses to emotion. The parasympathetic nervous system has a role in digestion and in maintaining the body's homeostasis when at rest.

How does the positive feedback loop work to create depolarization?

The voltage-gated sodium ion channels are activated and sodium ions rush into the neuron with their electrochemical gradient. As the membrane potential becomes more positive because of the presence of sodium ions, more voltage-gated sodium ion channels are activated. This cycle continues on and on, causing rapid depolarization to about +30 mV.

Why are there 2 gates for sodium voltage-gated channels?

To control the speed and have a short time period where Na+ goes through channel

Why is the trigger zone at the axon hillock?

Voltage-gated channels higher concentration

How does your brain know that you saw your laptop and not tasted it when both sensory receptors carry the same AP?

Where it comes from and where it goes to -each nerve pathway from sensory cells to brain is labeled to identify its origin

Myelin sheath

Whitish, fatty segmented sheath around MOST long axons -increases speed of nerve impulse transmission -formed by oligodendrocytes -cell has concentric layers of membrane that make up the myelin sheath (more layers = faster)

Is it possible to live without a corpus callosum?

Yes (Kim Peek) -savant, sometimes autism spectrum -remarkable abilities in very specific feature, but lacking in others

leak channels

always open, but specific

Receptive fields

area controlled by or perceived by one single sensory receptor

Ion pumps transport ions

b. against their concentration gradient

CNS

brain and spinal cord

gray matter

collections of unmyelinated axons, dendrites, and cell bodies that appear gray

What stimulates the Ca2+ gated channels to open in the synaptic knob? a. A ligand binding to the channels b. Voltage changes that took place as a result of Ca2+ flowing from the axon hillock c. Voltage changes that took place as a result of Na+ flowing from the axon hillock d. Active pumping of Ca2+ from the cytoplasm of the neuron and onto the ECF

c. Voltage changes that took place as a result of Na+ flowing from the axon hillock

The BBB is found between:

capillaries in brain and ECF of brain

Antiporter

carrier protein that moves two different solutes in opposite directions

Symporter

carrier protein that moves two solutes in the same direction

Uniporter

carrier protein that transports a single solute

Soma

cell body, most metabolically active part of neuron

Movement plan if tripped?

cerebellum

4 major anatomical parts of brain

cerebrum: higher mental functions diencephalon: processing, integrating, relaying info cerebellum: planning and coordination of movement brainstem: involuntary processes

What gates start to close and open around the threshold when coming down from the peak in an action potential?

close: K+, Na+ activation open: Na+ inactivation

What are basal nuclei

clusters of gray matter (cell bodies) embedded within white matter of brain

white matter

collections of myelinated axons that appear white

Broca's area

controls muscles involved in speech -present in one hemisphere (usually the left)

Nissl bodies

dark-staining clusters of ribosomes and rough endoplasmic reticulum inside the soma

declarative memory

data from our past experience

fissures

deep grooves in the cerebrum that increase the surface area of the brain

What effect will alcohol have on the reticular formation?

depresses

Channel-mediated diffusion

diffusion that occurs through channel

Carrier-mediated diffusion

diffusion that occurs through the use of carrier proteins

Facilitated diffusion

diffusion where charged or polar solutes (such as ion and glucose) cross the phospholipid bilayer with the help of a membrane protein

Simple diffusion

diffusion where nonpolar solutes (such as hydrocarbons and lipids, and gases such as O2 and CO2) pass straight through the phospholipid bilayer without assistance from a membrane protein

Lateralization

each hemisphere has abilities not shared with its partner

Contralaterality

each hemisphere of the cerebral cortex controls the other side of the body

Membrane potential

electrical potential (voltage), inside compared to outside

Why is resting membrane potential negative? How is it measured?

electrochemical gradients favor the diffusion of positively charged ions (K+) out of the cell and negatively charged ions into the cell, and positively charged ions diffuse through leak channels more easily than do negatively charged ions. It is measured with a voltmeter from inside to outside the cell.

How does a voltage-gated channel work?

gates open and close at different speeds, must reach threshold to open and close -protein, so changing charge around amino acid will change angle and configuration -ion selective

What is responsible for creating a new declarative memory?

hippocampus

The graded potential is ________ with a stronger stimulus

increased

Opening of the sodium activation gates lead to a flow of Na+ -____ the cell

into

How does a chemical synapse work?

involves passage of neurotransmitter substance between the cells -electrical potential changes to chemical -depolarization: local/graded potential -ligand gated channels because not enough voltage gated

sympathetic tone

keeps most blood vessels partially constricted and maintains blood pressure

Types of sensory receptors

mechano, chemo, thermo, photo, noci

Receptors

membrane protein that binds into a chemical messenger (ligan), which triggers changes in the cell

What 3 parts of brain stem?

midbrain, pons, medulla oblongata

Voltage gated channels will open up when the membrane potential reaches

minimum of -55 mV

4 kinds of sensory information?

modality, location, intensity, duration

What type of reflex is the simple stretch reflex?

monosynaptic

3 types of functional areas of the cerebral cortex

motor sensory multimodal association

Sally sustained damage to some autonomic ganglia. What part of the visceral reflex arc is interrupted? Sally sustained damage to some autonomic ganglia. What part of the visceral reflex arc is interrupted? A. sensory reception B. motor response in a target cell C. integration D. initiation of a motor impulse in the central nervous system (CNS)

motor response in a target cell

How does Na+ impact on membrane potential differ from K+ and why?

much lower because membrane is much less permeable to Na+ K+ leaves membrane more than sodium enters

Undersensitivy

need to put more intensity to stimulate brain enough to feel something

Axon

nerve fiber; processes that can generate and conduct action potentials

PNS

nerves and sensory receptors

substantia nigra

nuclei in midbrain, release dopamine to basal nuclei -inhibits basal nuclei by generating IPSPs

How does a cell depolarize?

opening sodium ligand-gated channels (more Na+ enters cell)

During repolarization, K+ flow ___________ the cell

out of

Nociceptors

pain is a feeling you ANALYZE, not just chemicals -nociceptors have high threshold -stimulus for pain: any type, only depends on intensity

primary somatosensory cortex

parietal lobe

Axolemma

plasma membrane of axon

somatotopy

point-for-point correspondence between an area of the body and an area of the CNS

Which of the following innervates target cells or organs of the autonomic nervous system (ANS)? Which of the following innervates target cells or organs of the autonomic nervous system (ANS)? A. autonomic ganglion B. somatic motor neuron C. preganglionic neuron D. postganglionic neuron

postganglionic neuron

primary motor cortex

precentral gyrus of frontal lobe -gray matter -controls skeletal voluntary movements

Example of multimodal association areas?

prefrontal cortex -language center (Broca's area

Movement plan?

premotor -> primary motor -> neurons -> muscle

Secondary active transport

primary active transport pump established a concentration gradient; potential energy of this gradient is then used to fuel the transport of a second substance against its concentration gradient

The sodium-potassium pump is a good example of a molecule that drives sodium and potassium via a _________ active transport mechanism (primary/secondary). The pump is considered an ___________ (symporter/ antiporter)

primary; antiporter

somatosensory association area

processes and analyzes sensory inputs coming from primary sensory cortex

Pons

respiratory center

lobe

rounded subdivisions of the cerebral hemisphere that contain groups of neurons performing specific tasks

Since a gradient of sodium (a gradient maintained by the sodium-potassium pump) is required for cotransport of glucose together with sodium, we refer to the glucose transport across the membrane as a _____________ active transport mechanism

secondary

Proprioceptive system

sense of self -position of body parts in space

Tactile system

sense of touch -includes vibration receptors, not just touch

What are the structural and functional divisions of the nervous system?

sensory (afferent): somatic, visceral motor (efferent): somatic; autonomic nervous system (smooth muscle, cardiac muscle, glands)

Sensory integration

sensory diet to work on specific inputs and receptors and systems to compensate for others

What are functions of the nervous system? Describe the process

sensory input - sensory receptors, PNS processing - CNS motor output - effectors, PNS

sulci

shallow grooves in the cerebrum that increase the surface area of the brain

working memory

short term

Dendrites

short, highly forked processes that receive input from other neurons, which they transmit in the form of electrical impulses toward the cell body; do not generate or conduct action potentials

graded potential (local potential)

short-range change in membrane potential upon stimulus -caused by opening sodium ligand-gated channels -proportional stimulus size -act locally -weakens with distance (spread in both directions; leaks out/thrown out by sodium-potassium pump) -takes place in many types of cells

rostral

situated or occurring near the front end of the body

caudal

situated or occurring near the posterior part of the body

non-declarative memory

skills, motor, and emotional

Tonic receptors

slow adapting receptors (pain doesn't go away) -notify on duration of stimulus

Continuous conduction

slow conduction that occurs in nonmyelinated axons

What creates the chemical gradient within a cell?

sodium-potassium pump restores chemical gradients and maintains resting membrane potential

Sodium-potassium pump throws __________ out and ____________ in

sodium; potassium

Vestibular system

spatial orientation -body in space during movement -equilibrium organs in inner ear: going up or down on elevator

Phantom pain?

still have nerve endings that fire APs Eventually, different parts of your body become other parts, sensation-wise

Axon Hillock

the cone-shaped area on the cell body from which the axon originates

Describe path of neural signals when trying to read out loud something from a different language

visual receptor -> visual cortex -> visual association area -> Wernicke's (no idea)

Describe path of neural signals, starting from seeing written word until saying word aloud

visual receptor -> visual cortex -> visual association area -> Wernicke's -> Broca's -> primary motor cortex

Major type of ion channels that trigger an action potential

voltage gated channel

Repolarization (step 3) is caused by the complete opening of the _____________

voltage-gated potassium ion channels