Unit 1 Learning Objectives: Physiology 335, Phys 335 UW Madison Exam 1

Define homeostasis

Homeostasis: a dynamic condition involving the maintenance of physiological variables in the extracellular fluid within ranges that are compatible with cell survival and whole-body survival.

Define physiology

Physiology: mechanisms of body function from molecules to cells to tissues, to organs to organ systems, to whole body- separately and integrated.

Define functional unit, and explain what structure is the functional unit of the human body

Functional units: the smallest part of something that demonstrates the most important properties of the whole

CELLS are the functional units, they can differentiate and form tissues, organs, and organ systems. "smallest piece of you that acts like you"

Explain why the cells of a multicellular organism must specialize

Cells specialize to make up 4 groups: epithelial cells (skin, kidney, GI tract) , connective-tissue cells (blood, ligaments) , nerve cells, and muscle cells. They need to specialize to be able interact with one another and maintain homeostasis.

List the 4 levels of organization of the human body, from smallest to largest

4 levels of organization: cells, tissues, organs, organ systems

Organelle, Cell, Tissue, Organ, Organ System, Organism

List the 4 basic tissue cell-type

4 basic tissue cell-types: epithelial tissue (blocks next to each other), connective tissue (random connections), nervous tissue, muscle tissue

List the major fluid compartments of the body, and draw a diagram on which you label them and indicate the volumes of each in an average-sized person.

Major fluid compartments:

Plasma = 3L

Interstitial fluid (between the cells) = 28 L

Intracellular fluid = 11 L

Describe the relationship between homeostasis, the cells of the body, and the organ systems

Organ systems maintain homeostasis and that's essential for survival of cells and cells make up the body systems that maintain homeostasis.

List some variables of the extracellular fluid that are homeostatically regulated.

Some ECF variables that are regulated: NA+, K+, CA2+, PH, GLU, O2, CO2, Temperature, Blood pressure, and more!

Differentiate between an "equilibrium" and a "steady state"

Steady state: a system where variables are not changing but energy must be added continuously to maintain a stable, homeostatic condition

Equilibrium: particular variable is not changing but no input of energy is required to maintain the constancy

Explain positive feedback control, using a physiological example.

Positive feedback control: change to a variable accelerates further change.

Example: Childbirth

Explain the concept of a "set point" and give an example of when a set point might change

Setpoint: steady-state value maintained by homeostatic control system

Examples: fever and elevated body temperature, exercise and blood pressure

Define feedforward control and describe an example of when this occurs in the body.

Feedforward control: stimuli signal a change in the internal or external environment, and a physiological adjustment begins to occur BEFORE the affected ECF variable has started to deviate from normal

Example: skin temperature detectors sense a change in external environment that could potentially change the body core temperature, and adjustments like shivering and blood vessel constriction happen before the core temp has started to change

Differentiate between the cytoplasm and cytosol of a cell.

Cytoplasm= cytosol and organelles

cytosol= intracellular fluid that surrounds cell organelles and nucleus

Describe the physical structure and chemical composition of a typical cell membrane.

Cell membrane composition: phospholipids (charged polar region and two long fatty acid chains which are nonpolar. Amphipathic)

Define fluid mosaic model.

Fluid mosaic model: can bend, twist, change shape BUT not stretch, heads on the outside, fatty acids face each other

Define diffusion

Diffusion: the movement of molecules from one location to another solely as a result of their random thermal motion

- ion channels

- facilitated (no energy required, can go in either direction)

- primary active transport (pumps, using ATP, burning energy)

Using an example of a solute moving between 2 compartments, define and differentiate flux and "net flux"

Flux: amount of material crossing a surface in a unit of time

net flux: down the concentration gradient

Explain how the distance between two points affects the time to reach diffusion equilibrium, and how that influences the size of cells.

Diffusion is slow with larger distance. Net diffusion limits the size of cells and unspecialized organisms; it is too slow for long distance movement.

Describe the main factor determining permeability of substances through a pure lipid bilayer, and list substances that are permeable and some that are not.

Main factor determining permeability: the hydrophobic core made of the tails of phospholipids

hydrophobic (lipid soluble) examples: O2, CO2, ethanol, fatty acids, steroids (EASILY PERMEABLE)

hydrophilic like large molecules, glucose, NA+, K+, Cl-, Ca2+ (CAN NOT PENETRATE)

Explain how substances not permeable to a pure lipid bilayer are able to be permeable through real cell membranes.

Diffusion through ion channels, subunits in a pattern forms a pore through the lipid bilayer

List the 2 major properties that determine the functional properties of an ion channel.

2 major properties:

selective for certain ions

gated by electrical, chemical, and mechanical events

List the 3 general mechanisms of gating of ion channels.

3 general mechanisms include electrical events (voltage; change charge may cause ion channel to open), chemical events (ligand; molecules that bind to ion channel changes shape of protein opening it), mechanical events (stretch; pressure to stretching ion channels opens)

Differentiate between carrier-mediated transport and ion channel diffusion.

Ion-channel diffusion: no help is given, just flows through the channel, speed is not limited

carrier-mediated transport: protein where things must bind to one side and then conformation change is required, very slow process

List the 3 general types of carrier-mediated transport, and list the properties that they have in common and the properties that make them different. Give specific examples.

3 types of carrier-mediated transport:

1) facilitated diffusion: net flux is down a concentration gradient however flux can go in either direction; movement is dependent on probability (more on outside, more likely to cross over); no energy required (all provided by conc. gradient)

2) primary active transport: pumps, burning energy using ATP, against a concentration gradient- UP (low conc.--> high conc.) (creates one)

3) secondary active transport: sodium moves across ion channel bringing another solute with it, energy provided by an ions gradient is almost always Na+

Describe in detail the mechanism of the Na+/K+-ATPase pump.

3 sodium ions bind to the ion channel allowing it to cross over the concentration gradient and changing conformation that allows 2 potassium ions to be pushed into the cell.

-it creates/maintains the gradients across plasma membrane

State the normal concentrations of Na+ and K+ in the intracellular and extracellular fluid, and explain what is responsible for maintaining the extracellular concentrations and what is responsible for maintaining the intracellular concentrations.

Intracellular fluid: Na+ 15mM, K+ 150mM, Cl- 7

Extracellular fluid: Na+ 145mM, K+ 5mM, Cl- 100

the pump regulates ICF concentrations

Kidney regulates ECF concentrations

Define cotransport, countertransport, symport and antiport, and give examples of each. (SECONDARY active transport)

-Cotransport (symport)= ion moves in same direction (high Na outside-->low Na inside, low X outside-->high X inside)

ex: glucose, AAs in GI, renal

-Countertransport (antiport) = ion moves in opposite direction of solute. If sodium binds outside, binding opens inside for something to leave the cell (DOWN: high Na outside-->low Na inside, UP: low X inside-->high X outside)

ex: Ca+2, H+

Outline an experiment that demonstrates flux rates and the difference in saturation behavior of simple diffusion and mediated transport.

What is speed of movement in (flux)?

depends on how molecule can enter the cell, if hydrophobic can enter faster (green line)

-Simple diffusion (green line) and ion channel (dotted line) eventually ion channel slows down

-Carrier-mediated transport causes saturation or max flux, diffusion does not- ion diffusion thru channels can saturate at non-physiologic conditions)

Given that lipid bilayers are not very permeable to water, explain how water is able to permeate cell membranes.

water can cross most cell membranes due to channels called aquaporins

Explain the difference between molarity (moles per liter) and osmolarity (osmoles per liter).

Molarity: not taking into account disassociation

Osmolarity: total count of molecules

Describe what will occur when there are differing concentrations of nonpenetrating solutes on two sides of a membrane that is permeable to water.

If the membrane is permeable only to water, osmosis will cause net water movement between compartments and in the equilibrium state there will be equal concentrations only if the compartment volumes change with the movement of water

Define osmotic pressure using a simple example of two fluid compartments separated by a semipermeable membrane.

Osmotic pressure example: more solute more water want to go there, causing a higher osmotic pressure

Define and differentiate between solutions described by these terms: isotonic, hypertonic, hypotonic, isosmotic, hypoosmotic, hyperosmotic. Explain what would happen to the volume of a cell dunked into a solution of each of those types.

TONIC MEANS NON PENETRATING SOLUTES

-TERMS DESCRIBE ECF ONLY

Isotonic: same nonpenetrating solutes in solution and in cell = no change in cell volume (requires 300 NP)

Hypertonic: nonpenetrating solutes more in solution than in cell= cell will shrink

Hypotonic: nonpenetrating solutes less in solution than in cell= water will go inside cell and will swell

Isosmotic: ALL THE PARTICLES, cannot tell if cell will shrink or cell unless particles were known

Hyperosmotic: do not know if all penetrating or not

Hypoosmotic: water will go into cell because more in cell than outside of cell (<300 total solutes: NP+P, too few total solutes to be iso-anything)

Define endocytosis and exocytosis.

Endocytosis: part of membrane comes into cell and brings particles inside, helps big proteins to come in

Exocytosis: lipid bilayer bound membrane the particle fuses with it and the membrane spits it into the cell

State the main role of the nervous system in maintaining homeostasis.

Nervous system in maintaining homeostasis: control system that receives info about ECF and external environment, integrates it, and directs activities of cells throughout the body to maintain homeostasis

List the two major anatomical divisions of the nervous system.

CNS: brain and spinal cord

PNS: everything else in nervous system (afferent: going to CNS efferent: coming from CNS)

Define synapse, presynaptic neuron, and postsynaptic neuron.

Neurons: presynaptic (sends a signal at a synapse), postsynaptic (receives a signal at synapse), synapse (one neuron sends a message very close to another neuron and message is transmitted)

Describe the locations and general functions of afferent neurons, efferent neurons, and interneurons.

afferent neurons (sensory neurons enter CNS), efferent neurons (motor neurons into PNS), interneurons (completely within the CNS)

Name the two types of glial cells that form myelin, and differentiate where they are found.

Glial cells (support function of neurons in NS): oligodendrocytes (create myelin sheath insulation in the CNS), Schwann cells (create myelin sheaths insulation in PNS)

Describe the interactions between positively and negatively charged particles, and how those interactions are changed depending on the amount of charge and distance of separation.

Positive and negative charges attract

negative and negative/ positive and positive repel

the greater the number of charges attracting to each other the stronger the energy (force)

force increases when distance between charges decreases

Define resistance, voltage, and current as they apply in biological systems.

Resistance: phospholipid is a resister that blocks electrical current to flow through

voltage: electrons flowing through when ion channel opens making phospholipid a bad resister

current: low-resistance pathway for movement of charges

Explain why intracellular fluid and extracellular fluid Na+ and K+ concentrations are different, and state the typical values found in each compartment.

The concentrations are different because some ions can be permeable while others try to follow and cant because they aren't permeable. The Na+/K+ ATPase Pump is the reason why the concentrations are different, it creates/maintains the ECF/ICF gradients, while kidneys maintain ECF concentrations.

Intracellular fluid: Na+ 15mM K+ 150mM

Extracellular fluid: Na+ 145mM K+ 5mM

Using a specific ion as an example, explain the concept of an equilibrium potential.

Equilibrium potential: the membrane potential at which these two fluxes become equal in magnitude but opposite in direction

Define electrochemical gradient and explain how it determines the direction of an ion's movement across a membrane.

Electrochemical gradient: balances chemical gradient; the driving force across a plasma membrane that dictates whether an ion will move into or out of cell; established by both the concentration difference and the electrical charge difference between the cytosolic and extracellular surfaces of the membrane

Determined by the relative magnitudes of the two opposing forces

Summarize in 3 steps how a resting membrane develops, beginning from a state where there is no membrane potential. Explain the role of relative permeability to Na+ and K+.

1. pump sets up gradient, pump Na out and K in, putting a small charge in the membrane to start

2. At first, more K diffuses due to leaky channels, permeability is greater

3. Eventually Na and K leak the same at steady RMP, K is happy at its equilibrium and Na has more permeability, both the concentration and electrical gradients favor Na entry

Explain the difference in the relationship between Cl- and the resting membrane potential between cells with chloride pumps and cells without chloride pumps.

Cells are permeable to chloride also, some have pumps for it some do not.

NO CL PUMPS: Na/K leaks and make a membrane potential, chloride will come out of the cell down the electro gradient that was built, concentration stabilizes following the RMP of -70

CL PUMPS: chloride equilibrium/gradient depends on its pump, the RMP takes into consideration Cl, Na, and K making it more negative (-72)

Define depolarization, overshoot, repolarization, and hyperpolarization.

Depolarization: potential becomes less negative (closer to zero) than the resting level

overshoot: inside of cell becomes positive relative to the outside

repolarization: membrane potential that has been depolarized returns to resting value

hyperpolarization: the potential is more negative than the resting level

Define graded potentials, and list 5 most important properties they possess.

Graded potentials: changes in membrane potential that are confined to a relatively small region of the plasma membrane

1. are proportional to size of stimulus

2. Decrease with decrease from stimulus site

3. Can be depolarizations or hyperpolarization

4, can summate with each other

5. Are short-distance signals that rely only on local flow of ionic currents

Define action potentials and describe how they are different from graded potentials.

Action potentials: large, rapid depolarizations and repolarizations of plasma membrane that can occur at high frequencies and travel long distances along axons or other excitable membranes(-can generate/propagate AP)

-voltage gated ion channels (closed, open, and inactivated)

Explain how the function of voltage-gated channels produces an action potential.

- leak channels keep RMP at -70, ligand opens channel, positive current rushes in (-70 to threshold)

- increase in Na permeability causes depolarization till inactivation blocks it, K opens but very slowly

- K leaves cell and makes cell more negative, repolarizing and shoot past RMP till it hyperpolarizes

- goes back to rest when only leaky channels are left

-K+ open at top, NA+ inactive at top of curve

Explain how the terms negative feedback and positive feedback relate to the function of voltage gated Na+ and K+ channels.

-the opening of Na channels and membrane depolarization is an example of positive feedback

- the opening of K channels and membrane repolarization is an example of negative feedback

List 4 properties that distinguish action potentials.

1. Are "all-or-none" like a gun

2. Are not graded by stimulus size (refractory periods, ion concentrations influence shape)

3. Can not summate due to refractory period

4. Do not decrease with distance; they propagate over long distances

-initiated in axon hillock (NOT terminal)

Define the absolute and relative refractory periods, and describe an experiment you could use to determine those periods.

-absolute refractory periods: no second action potential

-relative refractory period: stronger stimulus, small second action potential

-if 2 AP's met in middle on axon, both would disappear into each others abs. refractory period

Explain the mechanism of action potential propagation in unmyelinated and myelinated neurons. Define salutatory conduction.

Action potential propagation- starts @ axon hillock w refractory periods- highest density of voltage-gated Na+ channels clumped at nodes, velocity increases w axon diameter (squid giant axon)

-unmyelinated: goes in one direction, does not go backwards, no hurry (time required for each patch to depolarize)

-myelinated: cause "jumping", speed up action potentials (oligos in CNS and Schwann in PNS), acts as insulator

ex. Saltatory conduction

-Salutatory conduction: action potentials appear to jump from one node to the next as they propagate along a myelinated fiber (MUCH faster 100m/s, increased by myelination)

List two factors that determine the propagation velocity of action potentials along neurons.

1. velocity increases with axon diameter

2. Myelination speeds up

3. One way

Explain why action potentials normally propagate in only one direction along axons.

starts at the end with the axon hillock, the refractory period prevents it from reversing direction

Define convergence and divergence with regard to neuronal pathways, and explain the functional significance of each.

Convergence: hundred or thousands of synapses from many different presynaptic cells can affect a single postsynaptic cell; allows info from many sources to influence cells activity (referred Pain)

Divergence: a single presynaptic cell can send branches to affect many other postsynaptic cells; allows one cell to affect multiple pathways (sympathetic)

List cell types that neurons form chemical synapses with, and state the major difference between electrical and chemical synapses with regard to speed.

Chemical synapses occur with neuron, muscle cell, gland cell, and others

major difference: they are slower than electrical because a chemical must diffuse between cells and ionic current flows across postsyn. membrane only in response to NT release

List the presynaptic events involved in neurotransmitter release at chemical synapses.

1. AP propagates to terminal

2. Ca2+ channels open (voltage-gated)

3. Ca2+ activates vesicle exocytosis

4. Neurotransmitter diffuses across tiny gaps (15nm)

5. Ca2+ binds synaptotagmin (protein), causing SNARE complex to draw vesicle to plasma membrane

List the postsynaptic events occurring during signaling at excitatory and inhibitory synapses, and define excitatory postsynaptic potential (EPSP) and inhibitory postsynaptic potential (IPSP).

Excitatory: (exc. synapse- no need to depolarize post-synaptic membrane)

1. N.T binds to receptor

2. Ligand-gated channels open (chemical gating, ionotropic R)

3. Cations flow through (mainly Na+ OR Ca2+) (+ flow away from site on inside)

4. Net effect is depolarization (a tiny EPSP: 0.5mV per NT-R complex, threshold may be 15mV away- must summate many EPSPs!)

Inhibitory: (inh. synapse- need to reduce AP probability of occurring)

1. N.T binds to receptor

2. Ligand-gated channels open

3. Either K+ flux out or Cl- flux in

4. Net effect is either hyperpolarization (if K+ or Cl-) OR inhibit further depolarizations (Cl-)

List the reasons that postsynaptic potentials are relatively brief.

1. N.T rapidly bind and unbind

2. N.T reuptake into presynaptic terminal and/or

3. N.T diffusion away from the synapse and/or

4. Enzymatic destruction of neurotransmitter (and re-uptake of products)

-postsyn. potentials are graded, individual PSP's are small in neurons (0.5), summation of PSP's allows neuron integration at initial segment (lowest threshold cuz..)

State whether EPSPs and IPSPs are graded potentials or action potentials.

EPSP: Excitatory Postsynaptic Potential is a graded potential but creates an action potential

IPSP: Inhibitory postsynaptic potential is a graded potential that hyperpolarizes and doesn't create an action potential

Define presynaptic inhibition and presynaptic facilitation, and draw diagrams to explain the mechanisms of each.

Presynaptic inhibition: decreases depolarization and neurotransmitter release (decrease Ca2+ influx)

-decrease NT release from PreB to PostC, thus inhibit BOTH excit. and inhib. synapses

Presynaptic Facilitation: increases depolarization and neurotransmitter release (increase Ca2+ influx)

-increase NT release from PreB to PostC, this facilitate BOTH exc. and inh. synapses

List 8 ways that synaptic transmission can be altered by drugs and diseases.

8 ways-

1. Increase leakage of neurotransmitter from vesicle to cytoplasm, exposing it to enzyme breakdown

2. Increase transmitter release into cleft

3. Block transmitter release

4. Inhibit transmitter synthesis

5. Block transmitter reuptake

6. Block cleft or intracellular enzymes that metabolize transmitter

7. Bind to receptor on postsynaptic membrane to block or mimic transmitter action

8. Inhibit or stimulate second-messenger activity within postsynaptic cell

Explain the relative importance of the specific neurotransmitter released presynaptically and the receptor mechanisms occurring postsynaptically in determining whether a synapse is excitatory or inhibitory.

It is the receptor on postsynaptic side (channel) that determines whether IPSP or EPSP; but some neurotransmitters are consistently one or the other

Define neuromodulator, describe the general mechanism of action, and give an example.

Neuromodulator (hydrophilic): small peptides co-released with N.T. that activate 2nd messengers to alter metabolism

-regulate strength of synapse thru usually metabotropic receptors

-activate 2nd messengers at non-synaptic receptors

-interact with R's on either presyn. or postsyn. cells to modify effectiveness of the synapse at transmitting a signal

-mechanism of action: g protein activated which activates adenylyl cyclase and splits ATP to CAMP. CAMP activates kinases that alter the shape and purpose of other proteins that opens or closes an ion channel

Explain the mechanism and significance of long-term potentiation.

Long term potentiation: if you use synapse intensely (high frequency action potentials), repeated release of glutamate, AMPA opens over and over again, glutamate also bind to NMDA and drive Mg2+ out of the NMDA pore and changes its metabolism leading to long term memory

-strengthen synapse

-enough GLU released--> repels Mg2+, allows Ca2+ in, leads to LTP

List the structures that make up the central nervous system and peripheral nervous system.

CNS

-brain (cerebrum, frontal lobe, parietal lobe, occipital lobe, temporal lobe, thalamus, hypothalamus, brainstem, cerelbellum)

-spinal cord

PNS

- cranial nerves (optic, glossopharyngeal(blood pressure), vagus, accessory)

- spinal nerves (8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coxygeal)

State the general functions of the cerebrum, thalamus, hypothalamus, cerebellum, and brainstem, as listed in Table 6.7.

Cerebrum: contains cerebral cortex- generation of skilled movements, reasoning, learning, and memory

thalamus: sensory relay station

hypothalamus: homeostasis, hormones, autonomic nervous system, feeding and drinking behaviors

cerebellum: motor coordination

brainstem: contains all axons of neurons passing between the spinal cord, forebrain, and cerebellum

Define gray matter and white matter and compare their distributions in the brain and spinal cord.

White matter- axons/tracts, center of brain

gray matter- clusters of neurons, outer edge of brain

List the functions served by cranial nerves II, IX, X, and XI.

Cranial nerves 2: optic, afferent

cranial nerves 9: glossopharyngeal, efferent (swallowing and salivary glands), afferent (transmit info from taste buds and blood pressure receptors

cranial nerves 10: vagus, efferent (innervates skeletal muscles in thorax and abdomen), afferent (transmit info from receptors in thorax and abdomen)

cranial nerves 11: accessory, efferent, muscles in the neck

List the 5 regions of the spinal cord from top to bottom, state how many spinal nerves are associated with each, and explain what information is carried by spinal nerves

5 regions from top to bottom

1. 8 cervical- neck

2. 12 thoracic- chest cavity

3. 5 lumbar- lower back/legs/abdomen

4. 5 sacral- hip bones/ pelvis

5. 1 coxygeal

Compare and contrast the anatomy of neurons of the somatic motor system and autonomic motor system, and list the effectors of each.

Somatic: sensations you are aware of and muscles you can move consciously

visceral: afferent info you are not consciously aware of, and muscles, glands, and other cells you don't consciously control

Name the two subdivisions of the autonomic motor system, and describe the general effects each has on the body when it is active.

Afferent division: somatic, visceral, special

efferent division: somatic, autonomic (sympathetic, parasympathetic, enteric)

Sympathetic: fight or flight

parasympathetic: rest and digest

Define dual innervation and give some examples.

dual innervation- innervation of an organ or gland by both sympathetic and parasympathetic neurons

Explain what it means to say that one branch of the autonomic system is discrete, and one is generalized, and state which is which.

Parasympathetic: discrete, do one thing at a time

sympathetic: generalized, extreme, powerful, widespread activation

Differentiate the functions of somatic, visceral, and special sensory neurons, and give examples of what is detected by each.

Somatic sensory- touch, pressure, heat, cold, muscle force and position, pain

visceral sensory- blood pressure, oxygen levels, osmolarity

special sensory- vision, hearing, taste, smell

Explain the difference between "protein receptor" and "sensory receptor."

protein receptors: ligand binds to small receptors on cell

sensory receptors: large part of cell or whole cell

Define stimulus transduction.

stimulus transduction: convert stimulus into electrical signal

Define receptor potential and describe where they occur.

receptor potential: graded potential with size etc, occur in tip of afferent neuron or entire cell if the entire cell is a receptor

sub-threshold stimuli

graded potentials that don't give action potential

Differentiate between the function of rapidly-adapting receptors and slowly-adapting receptors, and state an alternate term for each.

Rapid-adapting receptors (phasic): tend to have on/off bursts of action potentials

slowly-adapting receptors (tonic):continue to fire the whole duration of a stimulus

Define sensory coding.

sensory coding: the conversion of stimulus energy into a signal that conveys the relevant sensory information to the CNS

Define sensory unit.

A single afferent neuron with all its receptor endings

Define receptive field.

the area of the body that leads to activity in a particular sensory neuron

Define adequate stimulus.

the right type of stimulus for the design of the receptor

Describe what happens to receptor potentials and action potentials as the intensity of stimulation of a sensory unit increases.

Intensity of stimulus increases, receptor potential increases, AP frequency increases

List two ways that stimulus intensity is encoded by afferent neurons.

1. Frequency

2. Recruitment

Define acuity.

precision of localizing a stimulus

Explain the concept of "labeled lines" with regard to sensory neural pathways.

labeled lines: a term describing the existence of dedicated pathways that carry specific modality from a specific body part to the brain

Stimulate one of these paths in the middle and the brain is fooled into perceiving the stimulus at the normal origin

Explain how overlapping receptive fields influence acuity.

Overlapping receptive fields- stimulate all 3 neurons, brain will detect which one has the highest frequency out of the three

Define and draw a diagram to explain lateral inhibition.

lateral inhibition: amplify the frequency difference, fibers inhibit each other, the most active fibers causing the greatest inhibition of adjacent fibers

Differentiate between the function of nonspecific and specific ascending neural pathways.

Nonspecific- causing general arousal and focusing attention

specific- provide detailed info about the modality, location, intensity, etc.

List the primary sensory regions of the cerebral cortex, and describe the anatomical location and function of each.

Primary sensory regions

1. Gustatory cortex

2. Auditory cortex

3. Somatosensory cortex

4. Visual cortex

List the association areas of the cerebral cortex, and describe the anatomical location and function of each.

Association areas

1. Frontal lobe

2. Parietal lobe

3. Occipital lobe

4. Temporal lobe

List 8 factors that can affect how we perceive sensory information.

8 factors:

1. Receptor adaptation

2. Emotions

3. Personality

4. Experience

5. Filtering by the thalamus- blocks distractions

6. Damaged pathways (phantom limbs)

7. Drugs like LSD

8. Diseases like schizophrenia

List the 5 major somatic sensations.

5 major somatic sensations:

1. touch

2. Pressure

3. Temperature

4. Pain

5. Body position and movement and itch

Name the receptors that allow us to sense temperatures, describe how they work, and explain the effects of menthol, capsaicin, and ethanol.

TRP- transient receptor potential (protein receptors)

at different temperatures certain proteins will open

menthol- opens cold receptors

capsaicin and alcohol- open when hot

Describe how pain pathways are modulated by higher centers, therapies, and drugs such as morphine and anti-inflammatory agents.

Anti-inflammatory- block prostaglandin synthesis

morphine- block ascending synapses

acupuncture- block descending inputs