Physiology Unit 1 LO

List the 2 major anatomical divisions of the nervous system

1. central nervous system 2. peripheral nervous system

List the 5 major somatic senses

1. touch 2. pressure 3. temperature 4. pain 5. body position and movement (kinesthesia) and itch

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

A solute is present in two compartments of a cell, compartment 1 and compartment 2. There is a high solute concentration in compartment 1 and a low solute concentration in compartment 2. Thus, there is high one way flux of solute from 1 --> 2, and a low one way flux of solute from 2 --> 1 (flux is simply the amount of a solute crossing from one compartment to the other within that given unit of time -- the rate of diffusion; there will always be flux in both directions of a selectively permeable membrane). Because the flux from 1 --> 2 is greater than that of 2 --> 1, the net flux in the cell is from compartment 1 --> 2

Define endocytocis and exocytocis

bulk movement of macroscopic particles or large proteins into and out of cells; requires lots of ATP and many membrane proteins

Define depolarization, overshoot, repolarization, and hyperpolarization

depolarization is when the membrane becomes less polarized (closer to zero) than its resting potential overshoot is when the membrane becomes oppositely polarized (or positive) repolarization is when the membrane returns from a depolarized state (zero) to its resting potential (negative) hyperpolarization is when the membrane becomes more polarized than at its resting potential (more negative than RMP)

Define homeostasis

homeostasis is a dynamic condition involving the maintenance of physiological variables in the extracellular fluid within ranges that are compatible with cell survival

Describe in detail the phototransduction mechanism occurring within a photoreceptor cell, explaining what processes dominate when light is striking the cell and what processes dominate when light is NOT striking the cell

photoreceptors are usually deporlarized at rest, and hyperpolarize when they are excited by an adequate stimulus In the absense of light: guanylyl cyclase enzyme converts GMP into high concentrations of the second messenger molecule cGMP, which maintains open ligand-gated cation channels for constant influx of Ca2+ and Na+ -- cell remains mostly depolarized (no significant changes) In the presence of light: the membrane wants to rapidly hyper polarize, retinal changes conformation and detaches itself from the photopigment (opsin), the opsin interacts with the neighboring protein transducin to activate cGMP-photodiesterase to degrade cGMP and close ligand-gated cation channels --results in loss of cation flux and hyperpolaization of membrane towards K+ equilibrium

State whether EPSP and IPSPs are graded or action potentials

postsynaptic potentials are GRADED

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

"labeled lines" is a terms describing the existence of dedicated pathways that carry info about a specific modality from a specific body part to the brain; if you stimulate on one pathway in the middle, the brain may be tricked into perceiving the stimulus at the normal origin

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

- frontal lobe association area - parietal lobe association area - occipital lobe association area - temporal lobe association area

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

- gustatory cortex (taste) - posterior to the central sulcus in the frontal lobe - auditory cortex - temporal lobe - somatosensory cortex - along central sulcus in the parietal lobe - visual cortex - occipital lobe

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 person

1. Extracellular fluid (33%): 14L Plasma (7%): 3L Interstitial fluid (26%): 11L 2. Intercellular fluid (67%): 26L SEE IMAGE

Describe three different ionic mechanisms that can mediate postsynaptic inhibition

1. Increased permeability to K+ causes K+ to go out of the cell and hyperpolarize the membrane (because Ek is more negative than RMP) 2. In a cell with Cl- active transport pumps, the Cl- concentration will increase inside the cell and hyperpolarize the membrane 3. In a cell without Cl- pumps, the membrane potential will remain at it's RMP and prevent depolarization

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. Na+/K+ ATPase pump creates concentration gradient (3 Na+ out, 2 K+ in) 2. At first, more K+ diffuses out ion channels, because the cell is more permeable to K+ (it'll move more down it's gradient than Na+), the membrane potential becomes more negative at Ek (because more K+ is exiting than Na+ coming in) = RMP reaches -70mV 3. Na+ and K+ leak THE SAME at a steady RMP

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

1. a steady RMP near Ek is allowed with K+ leak channels because Pk>Pna 2. membrane depolarizes to threshold potential 3. Na+ voltage-gated channel pops open and Na+ flood into the cell quickly continues to depolarize the membrane 4. Na+ channel inactivates, K+ voltage-gated channel gradually opens 5. membrane repolarizes with K+ running out of the cell 6. afterhyperpolarization, K+ channels close slowly and hyperpolarize because Ek<RMP 7. close of K+ voltage-gated channels returns membrane to RMP

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

1. action potential frequency increases with stimulus intensity (by afferent neurons into the CNS) 2. recruitment (or the "calling in" of other receptors in the area) is another indicator of stimulus intensity by the afferent neurons - stronger stimulus applied calls in more local afferent receptors

List the presynaptic events involved in neurotransmitter release at chemical synapses

1. action potential propagates to terminal 2. Ca2+ channels open 3. Ca2+ activates vesicle exocytosis 4. neurotransmitter diffuses across tiny gap(15nm)

List the 2 general FUNCTIONAL divisions of the nervous system and their 5 subdivisions

1. afferent division - somatic sensory - visceral sensory - special sensory 2. efferent division - somatic motor - autonomic motor

List 4 properties that distinguish action potentials

1. are "all or none" (like a gun) - will not haooen without hipping threshold potential/voltage 2. are not graded by stimulus size 3. can NOT summate, due to refractory period a. Absolute refractory period (no second action potential within this time) b. Relative refractory period (requires stronger stimulus during this time, smaller second action potential) 4. do NOT decrease over distance; they propagate over long distances

List 2 factors that determine the propagation velocity of action potentials along neurons

1. diameter - velocity increases with diameter 2. myelination - myelination SPEEDS UP - myelination where you need speed, like motor neurons or sharp pain non-myelin SLOW - where no hurry, like regulation of digestion, dull aching pain

List the 3 general mechanisms of gating ion channels

1. electrical events (voltage-gated) 2. chemical events (ligand-gated) 3. mechanical events (stretch-gated)

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

1. facilitated diffusion - net flux is DOWN a concentration gradient (flux in either direction) EX. glucose entry into MOST body cells 2. primary active transport - AGAINST a concentration gradient directly uses/splits ATP EX. Na+/K+ ATPase pump 3. secondary active transport - AGAINST a concentration gradient and energy provided by an ion's gradient (usually sodium), can be an antiporter (countertransport) or symporter(cotrasnport) EX. glucose, amino acids

List 4 general mechanisms causing the termination of postsynaptic potentials

1. neurotransmitter rapidly binds and unbinds 2. neurotransmitter reuptake into presynaptic terminal and/or 3. neurotransmitter diffusion away from the synapse and/or 4. enzymatic destruction of neurotransmitter (and products reuptaken)

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

1. oligodendrocytes in the CNS 2. schwann cells in the PNS

List 8 factors that can affect how we perceive sensory info

1. receptor adaptation 2. emotions 3. personality 4. experience 5. filtering by the thalamus 6. damaged pathways (phantom limb) 7. drugs like LSD 8. disease like schizophrenia

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

1. selective for certain ions (some are non-selective) 2. gated by: electrical events (voltage) , chemical events (ligand), mechanical events (stretch)

Detail the functional anatomy of somatic, parasympathetic, and sympathetic motor neurons, including details such as the number and lengths of the neurons, the neurotransmitters released, the neurotransmitter receptors, and the target tissues

1. somatic nervous system NT and receptors within the CNS a single neuron acts on its effector, NT Ach is released and NAch R (Ach receptor) binds the NT of effector, skeletal muscles 2. autonomic - parasympathetic division NT and receptors within the CNA a long preganglionic/presynaptic cell synapses NT Ach onto a short post ganglionic cell (in ganglion near to effector) which has NAchR, short postganglionic cell synapses NT Ach onto effector (smooth or cardiac muscles, glands, or other cells) which has MAchR 3. autonomic - parasympathetic division NT and receptors short preganglionic cells synapse NT Ach onto long postganglionic cells (in ganglionic chain near spinal cord) which have NAchR, long post ganglionic cells synapse NE/A onto effectors (smooth or cardiac muscles, glands, or other cells) which have Adergenic receptors OR Short preganglionic cells release NT Ach to endocrine gland adrenal medulla which had NAchR and releases NT Epinephrine through the bloodstream to adergenic receptors on effectors (smooth or cardiac muscles, glands, or other cells)

List the 3 functional subdivisions of the autonomic motor neurons

1. sympathetic 2. parasympathetic 3. enteric

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

1. sympathetic nervous system - fight or flight 2. parasympathetic nervous system - rest and digest

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

Absolute refractory period is the period of time following an action potential in which a second action potential cannot happen Relative refractory period is the period of time following an action potential that a second, less strong action potential can happen, but requires a much larger stimulus two stimuli at two different points in time; first stimuli is a small voltage increase, Na+ channels inactivated-- in refractory period, eve huge stimulus will not cause an action potential--in relative refractory period, larger stimulus will causes smaller action potential, because fewer sodium channels were ready/ recovered to open

Explain how a spinal cord injury could result in loss of pain and temperature information from one side of the body and loss of fine touch on the other side of the body

Because the ALS pathway decussates at the level of entrance, if the injury were to the right anterolateral column of the spinal cord, loss would only occur to the left side of the body; if the injury were on the right dorsal column, loss would occur to the right side of the body (example - right side laceration of entire spinal cord)

List the structures that make up the CNS and the PNS

CNS: brain and spinal cord PNS: cranial nerves and spinal nerves

Recognize the cerebrum, and know the names and locations of the 4 lobes that comprise it

Cerebrum: Parietal, occipital, frontal, temporal lobes

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

Cervical - 8 Thoracic - 12 Lumbar - 5 Sacral - 5 Coxygeal - 1 Each nerve has afferent and efferent neurons to and from that level of the body all have somatic, some have visceral components

Define duel innervation and give some examples

Dual innervation is innervation of a single effector that is both sympathetic, and parasympathetic... the effects on the organs or effectors are typically opposite to each other

State the normal concentrations of Na+ and K+ in the intercellular fluid and extracellular fluid, and explain what is responsible for maintaining both of those concentrations

ECF conditions: regulated by the kidney - Na+ 145 mM - K+ 5 mM ICF conditions: regulated by the pump - Na+ 15mM - K+ 150mM

Calculate the equilibrium potential of a cation and of an anion using the Nernst equation

Ek+ = (61/+1)log[5]/[150] = -90mV Ecl- = (61/-1)log[100/7] = -69mV

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

ICF and ECF concentrations of Na+ and K+ are different because the Na+/K+ ATPase pump sets up and maintains ECF/ICF concentration gradients; typical values: [Na+] inside = 15 mM [Na+] outside = 145 mM [K+] inside = 150 mM [K+] outside = 5 mM

List the functions associated with CN II, IX, X, and XI

II: Optic - carries afferent sensory info from the eye IX: Hypoglossal - innervates efferent skeletal muscle involved in swallowing and parotid glands; transmits afferent info from the baroreceptors (analyzing BP), chemoreceptors (analyzing blood gas-levels), inner-ear skin, and taste buds form the posterior aspect of the tongue X: Vagus - innervate efferent skeletal muscles of the pharynx, larynx, and smooth muscle/glandular tissue in the thorax/abdomen; transmits afferent info from receptors in the thorax and abdomen XI: Trapezius - innervates sternocleidomastoid and trapezius skeletal muscles

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

In a constant cycle, body/organ systems maintain the homeostasis of extracellular fluid which is essential for the survival of the body's cells and their specialized functions, specific to the tissue, organs, and organ systems they make up SEE IMAGE

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

In unmyelinated neurons, local current from the opening of ligand-gated channels depolarizes the membrane towards the threshold potential and creates and action potential that depolarizes the next section over to the threshold and thus propagates in one direction from the axon hillock with sequential opening and closing of Na+ and K+ channels--happens over a couple of milliseconds In myelinated neurons, action potentials appear to jump from one node to the next (salutatory conduction) due to less leakage of ions, less Na+ channels

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.

Isotonic: ICF and ECF have equal concentrations; no change in cell volume Hypertonic: ICF < ECF concentration; cell shrinks Hypotonic: ICF > ECF concentration; cell will swell Isosmotic: total ECF osmolarity 300 mOsm/L (normal ICF level); not sure if cell will shrink or swell Hypoosmotic: total ECF osmolarity < 300 mOsm/L; water will go in either direction (cell can shrink or swell) Hyperosmotic: total ECF osmolarity > 300 mOsm/L; not sure if cell will shrink or swell

Write the equation applying Fick's Law of diffusion to biological membranes

J = P * A * (Co-Ci) J = net flux (rate of diffusion) of a given molecule P = permeability coefficient (ease of molecule's movement through the membrane) A = surface area of the membrane Co = concentration of molecule outside membrane Ci = concentration of molecule inside membrane

Define myopia, describe what causes it, and explain how it can be corrected

Myopia is nearsightedness, it's caused by either having too curved of a cornea, or having too long of an eye it's corrected using a diverging lens

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

SEE FLASHCARD SET

Compare/contrast the major characteristics of pathways by which substances cross membranes (table 4.2)

SEE IMAGE

Draw a cross-section of the eye, and label all of the structures involved in visual reception and processing

SEE IMAGE

Draw a diagram demonstrating that sensory receptor potentials are graded while action potentials arising from them are not

SEE IMAGE

Draw a diagram showing how the curvature of the cornea and lens focus a point of light on the retina

SEE IMAGE

Draw a diagram showing the mechanism of negative feedback of body temperature

SEE IMAGE

Draw a generic diagram showing how the 5 components of a negative feedback system connect the deviation of a variable from normal to the correction of that deviation

SEE IMAGE

Draw a simple neuron and label the dendrites, cell body, axon hillock, axon, and axon terminals

SEE IMAGE

Draw an action potential and label threshold potential, resting potential, depolarization, afterhyperpolarization, and repolarization

SEE IMAGE

Draw and label a cross-section of the spinal cord, showing its relationship with spinal nerves, and trace the flow of neuronal signaling in afferent and efferent neurons

SEE IMAGE

Draw the cells involved in neurotransmission of the "ON" bipolar cell pathway under conditions when NO light is striking the photoreceptor, and also in conditions when light strikes the photoreceptor

SEE IMAGE

Draw the neuronal pathway carrying pain sensation to the brain, including the neurotransmitters involved and the brain regions where synapses occur

SEE IMAGE

Given a patient with damage to each of the following parts of the visual pathway (unilateral or bilateral), describe what a patient would see through each eye when staring at a white wall: optic nerve, optic chiasm,optic tract, primary visual cortex

SEE IMAGE

Sketch the visual pathways of both eyes, starting from the retina and terminating in the primary visual cortices of the two cerebral hemispheres

SEE IMAGE

Draw a diagram of an experimental apparatus and graph used to measure resting potential, and state the typical average value of the resting membrane potential

SEE IMAGE -70 mV is the avg resting membrane potential

Draw a diagram that distinguishes the function of the voltage-gated Na+ channels and voltage-gated K+ channels that produce the typical neuronal action potential

SEE IMAGE 1. Membrane depolarizes (negative voltage---> positive voltage) 2. Na+ channel pops opens, Na+ floods into the cell 3. after a little time, NOT at a certain voltage (more positive), Na+ channel inactivates 4. K+ channel slowly opens, K+ floods out the cell 5. Membrane repolarizes (positive voltage--->negative voltage 6. Na+ channel snaps shut 7. K+ channel closes slowly

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

SEE IMAGE AXON-AXONIC SYNAPSE - presynaptic axon synapses on another presynaptic axon to alter NT release: presynaptic inhibition decreases depolarization and neurotransmitter release (with decreased Ca2+ influx) presynaptic facilitation increases depolarization and neurotransmitter release (increased Ca2+ influx)

Draw a diagram of an electrical synapse, describe their function, and list some body locations where they occur

SEE IMAGE electrical synapses happen between heart, smooth muscle, and some brain cells (esp during fetal development); electrical synapses use gap junctions between cells to conduct electrical signals directly from cell-to-cell

Define and draw a diagram to explain lateral inhibition

SEE IMAGE lateral inhibition enhances acuity because info from afferent neurons with more lateral receptors (at the edge of a stimulus) are inhibited; to begin with, the outermost parts of the stimulus have a lower AP firing rate than does the center, then inhibitory interneurons from the central neuron further inhibit the signals the outermost signals also inhibit the central neuron, but it doesn't have as large of an effect

Draw a diagram and use it to explain synaptic integration, defining in particular temporal and spatial summation

SEE IMAGE temporal summation - timing of PSPs from the same cell can summate them if close enough in time lapse spatial summation - place/location of PSP in space can summate them if in close enough proximity though they are in different locations

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

TRP or transient receptor potentials are a family of ion channels that gate open only at specific temperature ranges some are also gated chemically; menthol opens cold receptors and capsaicin (from hot peppers) and ethanol (from alcohol) open warmth receptors even though they are actually at room temperature (which is why these channels are chemically-gated)

Differentiate between the ascending pathway taken by pain and temperature receptors and the ascending pathways carrying body movement, limb position, fine touch, and pressure information

The ALS or anterolateral system pathway is used to sense temperature and pain-- afferent neurons from temperature and pain receptors enter the spinal cord through the dorsal roots, synapses in the dorsal horn, decussate at the same level it enters, passes through the anterolateral column, and synapses in the thalamus, then the somatosensory cortex The dorsal column pathway is used for body movement, limb positions, fine touch, and pressure info--afferent neurons enter the spinal cord at the ventral root and pass through the dorsal column, they synapse in the brain stem, then decussate, where they'll then synapse in the thalamus and somatosensory cortex

List the important aspects of the function of the Na+/K+ ATPase pump

The Na+/K+ ATPase pup is found in every cell, and is the reason for the gradients of Na+ and K+ between intercellular fluid and extracellular fluid KNOW about the cycle: 1. 3 Na+ moved out 2. 2 K+ moved in 3. ATP provides energy directly 4. Creates Na+/K+ gradient (K+ conc. high inside, low out) (Na+ conc, low inside, high out)

Describe the main factor determining permeability of substances through a pure lipid bilayer, list substances that are permeable nd some that are not, and explain how substances not permeable to a pure lipid bilayer are able to be permeable through real cell membranes

The main factor determining permeability is the hydrophobic core due to the fatty acid phospholipid tails 1. hydrophobic (lipid soluble) substances are easily permeable EX. oxygen, carbon dioxide, ethanol, fatty acids, steroids 2. hydrophilic substances can NOT penetrate the phospholipid barrier without the help of transport proteins or ion channels EX. charged polar particles like sodium, potassium, chloride, and calcium

With regard to the somatosensory cortex, define somatotopic map and explain the significance of the different sizes of body parts in the map

The somatotopic map, or sensory homunculus is a map based on the ends of sensory axons which are grouped by their peripheral sensory neuron's placement giving input to the pathways; the more highly innervated regions of the body/more cortical area determines the size of the body part on the map and how much area is associated with that body part

Write the equation known as Ohm's law, and write a sentence explaining its functional application in biological membranes

V=IR OR I=V/R V = membrane potential I = current flow (movement of charged ions) R = resistance to current flow (openness of ion channels) 1. The first equation describes how ion flow affects membrane potential 2. The rearranged equation describes how membrane potential and resistance determines the flow of ions

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

a functional unit is the smallest part of something that demonstrates the most important properties of the whole; cells are the functional units of the human body

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

a neuromodulator is usually a small peptide that is co-released with NT, it activates 2nd messengers; usually at non-synaptic receptors or metabatropic it tends to modify the postsynaptic neuron's response to NT, heightening or dampening the effects it can interact with receptors on either presynaptic or postsynaptic cells to modify effectiveness of synapses at transmitting a signal EX. histamine

Define sensory unit

a sensory unit is a single afferent neuron with all of its receptor endings

Define synapse, presynaptic neuron, and postsynaptic neuron

a synapse is the chemical communication between neurons and other cell types between small gaps a presynaptic neuron is a neuron that sends a signal at a synapse a post synaptic neuron is a neuron that receives a signal at a synapse

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

a typical cell membrane is made of a "lipid bilayer" which is two layers of phospholipids; these are amphipathic, meaning that they have both hydrophilic head groups (made of polar/charged groups) and hydrophobic tails (made of fatty acid chains), they do not make cellular bonds and are free to move freely/laterally they arrange much like a flexible fluid layer, and do not allow polar/charged molecules to enter...much like a plasma membrane

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

action potentials are large, rapid depolarizations and repolarizations of the plasma membrane that can occur at high frequencies and travel long distances along axons or other excitable membranes; action potentials are much different from graded potentials because they are very brief, and create large alterations in the membrane potential at a very fast pace, over great distance

Explain how overlapping receptive fields influences acuity

action potentials frequency varies across the area of a receptive field, which makes acuity HIGHER in overlapping receptive fields; when the stimulus affects receptive fields of several afferent neurons, the area with the strongest response (of AP frequency) indicates the center of the stimulus

Define acuity

acuity is the precision of localizing a stimulus; depends on neuronal convergence

describe the locations and general functions of afferent neurons, efferent neurons, and interneurons

afferent neurons are sensory neurons that originate in the PNS with axons that enter the CNS efferent neurons are motor neurons that originate in the CNS with axons that enter the PNS interneurons are integrating neurons found entirely in the CNS

Define fluid mosaic model

all cell membranes have the same generalized structure but consist of a mosaic, or mixture of membrane proteins and lipids that are allowed to move freely within the bilayer; cholesterol helps regulate the membrane fluidity due to its polar and nonpolar interactions with the phospholipids

Define adequate stimulus

an adequate stimulus means that the stimulus is the correct modality for the way that receptor is designed to work EX. light photons are an adequate stimulus for receptors in the eye

Draw a diagram that explains the concept of an electrochemical gradient and how that affects the movement of an ion through a cell membrane

an electrochemical gradient describes how both concentration and membrane charge affects ions so it is created by two factors, the membrane potential which acts on forces of voltage/charge and the concentration potential which acts on the force of the concentration gradient; the movement on an ion through the cell membrane depends on the magnitude of each of the forces, which can be opposing SEE IMAGE

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

an electrochemical gradient describes the direction and magnitude of both the flux created by membrane potential (electric/voltage difference) and the flux created by the ion's concentration difference; the factor with a greater difference determines the direction of an ion's movement across a membrane in order to establish an equilibrium potential

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

an equilibrium is a relatively constant state that does NOT require energy input to maintain, on the other hand, a steady state is a relatively constant state that requires the constant input of energy to maintain

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

an equilibrium potential is the voltage difference across the membrane that causes flux of a given ion species that is equal but opposite to the flux that is created by it's concentration gradient there is an electrochemical gradient across the membrane for all ions, as long as the flux of the concentration gradient for K+ is greater than the flux of its membrane potential, there will be a net flux of K+ from the compartment of higher concentration to the compartment of lower concentration, and the membrane potential will increase...eventually the membrane potential will reach a value negative enough to produce a flux that is equal but opposite to the concentration gradient of K+, this value is its equilibrium potential

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

as the intensity of a stimulus increases, the receptor potential in the sensory endings increases and the action potential frequency in the sensory neuron axon increases

Explain why the cells of a multicellular organism must specialize

cells of a multicellular organism must specialize in order to cope with unique problems within a body; differentiated cells form tissues, organs, and organ systems within the body

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

cells, tissues, organs, organ systems

Explain what property of light rays determine color

color is determined by wavelength; the human eye can detect a small portion of the electromagnetic spectrum

Explain how color vision occurs

color vision begins with the activation of photopigments in the cone photoreceptor cells, the human retina has three types of cones, one responding best in blue (short wavelength), green (middle wavelength), and red (long wavelength) light and each cone is excited over a great range of wavelengths with the greatest response being in the middle of the range

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

convergence - many presynaptic neurons send a signal to a single postsynaptic neuron; allows information from many sources affect one cell's activity divergence - a single presynaptic neuron sends signals to many post synaptic neurons; allows information to reach many systems/multiple pathways

Define stimulus transduction

converting a stimulus (photon, stretch, or other) into an electric signal which is how the brain interprets action potentials

Define cotransport, countertransport, sumport, and antiport, and give examples of each

cotransport (symport): in secondary active transport, both molecules travel the same way across cell membrane EX. Na+ conc. gradient providing energy for transport INTO cell; glucose/amino acids transport AGAINST conc. gradient INTO cell countertransport (antiport): in secondary active transport, molecules travel oppositely across the membrane EX. Na+ conc. gradient providing energy for transport INTO cell; Ca2+ /H+ transport AGAINST conc. gradient OUT of cell

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

drugs and diseases might... 1. increase leakage of NT 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 (degrading enzymes) 7. bind to receptor on postsynaptic membrane to block (antagonist) or mimic (agonist) transmitter action 8. inhibit or stimulate second-messenger activity within postsynaptic cell

List the 4 basic tissue cell-types

epithelial tissue, muscle tissue, nervous tissue, connective tissue

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

feedforward regulation is where a stimuli signals a change in the internal or external environment, and a physiological adjustment begins to occur BEFORE the affected extracellular fluid variable has started to derive from normal; it's done to minimize the magnitude of deviation from normal (even preventing any/all deviation in some cases) for example, skin temperature detectors sense a change in external environment that could potentially change the body core temperature, and adjustments like shivering and contraction of the blood vessels happen BEFORE the core temperature changes

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

flux into the cell with simple diffusion is ultimately proportional the extracellular solute concentration, where as the flux into the cell with mediated transport reaches a maximal level which depends on the number of transporter proteins and their inherent rate of conformational change when bound to a molecule--thus it cannot become fully saturated as simple diffusion (mostly) can

Define graded potentials, and list the 5 most important properties they posess

graded potentials are changes in a membrane potential that are confined to a relatively small portion of the plasma membrane 1. they're proportional to the size of the stimulus 2. they decrease with distance from the stimulus site 3. they can be depolarizations or hyperpolarizations 4. they can summate with each other 5. they are short-distance signals that rely on local flow of ionic currents (they don't rely on voltage-gated channels)

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

gray matter consists of unmyelinated axons or cell bodies white matter consists of myelinated axons of cell bodies in the brain, there is a greater abundance of white matter on the inside of cerebral hemispheres in the spinal cord, there is a greater abundance of gray matter on the inside (ventral and dorsal horns) and white matter around the outside

Define hyperopia, describe what causes it, and explain how it can be corrected

hyperopia is farsightedness, it's caused by either having too flat of a cornea, or having too short of an eye it's corrected using a diverging lens

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

in cells without chloride pumps, K+ and Na+ set RMP = Ecl- and in cells with chloride pumps (outward); the pumps determine the Cl- gradient and Ecl- is NEGATIVE to the RMP, it helps K+ to make the RMP negative

Differentiate between carrier-mediated transport and ion channel diffusion

in ion channel diffusion there is no limit to how many molecules will flux, in carrier-mediated transport there is a limit to the rate at which molecules can diffuse (because the systems that use membrane proteins to move substances across membranes that can't move by simple diffusion) THINK: ferry boat

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

in this case, osmosis will cause net water movement between compartments and (assuming the walls can stretch) there will be equal concentrations only if the compartment VOLUMES change with the movement of water

State the main role of the nervous system in maintaining homeostasis

it is a control system that receives info about the internal (ECF) and external environment, integrates it and directs activities of cells throughout the body to maintain homeostasis

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/channel that determines whether the PSP is excitatory or inhibitory although some NT are consistently one or the other if the presynaptic neuron is excitatory, Na+ will flood out of the cell -- membrane depolarizes if the presynaptic neuron is inhibitory, either K+ will flood out of the cell, or Cl- will flood in -- membrane does not depolarize or hyperpolarizes

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

molarity is the solute concentration, whereas osmolarity is the total solute concentration based on total number of solute particles EX. NaCl at 1 M has an osmolarity of 2 OsM glucose at 1 M has an osmolarity of 1 OsM

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

net diffusion limits the size of cells and unspecialized organisms because it is too slow for long distance movement...organisms move at random

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

neurons form chemical synapses with neurons, muscle, gland, and other cells chemical synapses are much slower than electrical synapses because a chemical is required to diffuse between cells whereas electrical synapses use gap junctions between cells to conduct electrical signals directly from cell-to-cell

Compare and contrast the anatomy of the neurons in the somatic motor system and autonomic motor system, and list the effectors of both

neurons in the somatic nervous system are singular and synapse directly ont their effector, skeletal muscle there are two neurons in the autonomic nervous system, a presynaptic neuron which synapses on a postsynaptic neuron in the ganglion, and a postsynaptic neuron that synapses onto it effector, smooth, or cardiac muscles, glands, or GI neurons

Differentiate between the function of nonspecific and specific ascending neuronal pathways

nonspecific ascending pathways have convergence, and notify the brain that "something" is happening, generally causing arousal and focusing attention in that area specific ascending pathways are the "labeled lines" that provide detailed info about the modality, location, intensity, etc.

Describe the anatomy of an afferent neuron, detailing which portions are in the peripheral nervous system, and which are in the central nervous system

on an afferent neuron, the sensory receptors, axons, and cell body are located in the peripheral nervous system; the axon terminal is located in the central nervous system where it synapses with cell bodies of interneurons

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

pain pathways are modulated.. anti-inflammatory drugs by blocking prostaglandin synthesis, morphine and endogenous opiates block ascending synapses, somatic receptors activation can stimulate descending neurons that inhibit transmission (TENS or rubbing your bump)

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 division of the ANS is discrete, the sympathetic division of the ANS is generalized, this means that when the sympathetic nervous system is in action, it activates ALL processes of physical exertion and inhibits processes that do not help, whereas the parasympathetic nervous system in action activates processes that help during the resting state and inhibits any processes that aid in physical exertion

Define physiology

physiology is the study of the mechanisms of body function from molecules to cells to tissues, to organ systems, to whole body--separately and integrated together; physiology is the basis of medical practice in seeking health/wellness benefits

Describe the anatomical differences that result in the lips having very high acuity, while others, like the back of your arm, have very low sensory acuity

places in the body that have high acuity or better multi-point discrimination have a larger number of individual sensory neurons with smaller receptive fields

Explain positive feedback, using a physiological example

positive feedback sometimes occurs when change to a variable accelerates further change and ends in a terminating event; an example is childbirth, when the baby puts pressure on the mother's cervix, stretch receptors send nerve signals to the hypothalamus which tells the posterior pituitary gland to produce oxytocin, which causes the cervix to contract and push the baby further toward it's opening...the cycle continues and the terminating event is the birth of the baby

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

postsynaptic events at ... ...excitatory synapses: 1. neurotransmitter binds to receptor 2. ligand-gated channels open (ionotropic receptors stimulates movement of ions with electrochemical gradient) 3. cations flow through (mainly Na+) 4. Net effect is a depolarization (a tiny EPSP - EXCITATORY POSTSYNAPTIC POTENTIAL) ...inhibitory synapses: 1. neurotransmitter binds to receptor 2. ligand-gated channels open 3. EITHER K+ out or Cl- in 4. net effect is either: - prevents depolarization ( if channels are Cl- and do NOT contain pumps so Ecl = RMP) -hyperpolarization if channels are K+ or channels are Cl- with pumps to make Ecl- negative) INHIBATORY POSTSYNAPTIC POTENTIAL

Define presbyopia, describe what causes it, and explain how it can be corrected

presbyopia is farsightedness or "old vision" that is due to the lens losing flexibility to snap to a rounded shape it's corrected using a converging lens

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

rapidly adapting receptors (or PHASIC receptors) tend to have on/off bursts of action potentials - they aren't continually firing slowly adapting receptors (or TONIC receptors) continue to fire the whole duration of a stimulus

Define receptor potential and describe where they occur

receptor potentials are graded potentials that occur due to gated ion channels causing a change in flux across the receptor membrane (thus changing membrane potential) the occur in specialized sensory cells

Define referred pain, and describe the mechanism it results from

referred pain is a somatic symptom that is the result of visceral injuries/problems because afferent pathways converge and are non-specific

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

resistance is the "openness of ion channels" or how reduced is the ability fir current to flow (phospholipid bilayer has a high electric resistance decreased when ion channels open) voltage is a cells membrane potential; or the membrane's potential to do work current is the movement of charged ions (open ion channels are a low resistance pathway for movement of charges/current)

Name the two general types of photo receptor cells and describe their visual properties

rods - respond in LOW light, LOW acuity, NO color vision cones - Require bright light, HIGH acuity, Color vision

Define sensory coding

sensory coding is the conversion of a stimulus energy into a signal that conveys the relevant sensory info to the CNS

Explain the difference between protein receptor and sensory receptor

sensory receptors comprise of the peripheral ends of a neuron in the PNS and are activated by currents, which start graded potentials creating action potentials to carry to the CNS protein receptors are within a cell's membrane and activate transduction pathways or influence gene transcription which directs cell behavior

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

separated charges have the potential to do work, positive and negative charges have attractive forces, 2 negatively or positively charged particles have repulsive forces; depending on the amount of charge and distance between them, these forces can be strengthened or weakened: greater charge = greater attraction/repulsion and lesser distance = greater attraction/repulsion (in coherence with basic charge interactions)

List some variables of the extracellular fluid that are homeostatically regulated

sodium, potassium, calcium, pH, glucose, oxygen, carbon dioxide, temperature, blood pressure, etc.

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

somatic sensory- aware of senses like touch, pressure, heat, cold, muscle force and position, and pain visceral sensory- not aware of these senses like blood pressure, oxygen levels, and osmolarity special sensory- typical senses like vision, hearing, taste, and smell

Define accommodation reflex, and give a detailed example of how it works in focusing on objects in different distances

the accommodation reflex describes the adjustments for clear images based on distance so that it causes either contraction of the ciliary muscle in the eye that allows the lens to assume a more round shape , or relaxed ciliary muscle which pulls the lens to be flat; at far distances, the ciliary muscle is relaxed and the zonular fibers are taught --lens is flat = less refraction at close distances, the ciliary muscle contracts via parasympathetic nerves and slackens the zonular fibers--lens is curved = more refraction

Differentiate between the cytoplasm and cytosol of a cell

the cytoplasm of the cells is the area surrounding the nucleus, this consists of organelles and cytosol fluid; intercellular fluid is made up of the cytosol fluid and fluid inside of organelles, however, cytosol is by far the largest intercellular fluid compartment of the body

Explain the mechanism and significance of long-term potentiation

the mechanism of long term potentiation couples frequent activity across a synapse and lasting changes in the strength of signaling across that synapse, which is important in learning and memory mechanism when a presynaptic neuron fires action potentials... 1. glutamate is released from the presynaptic neuron 2. glutamate binds to both NMDA and AMPA receptors on postsynaptic cell 3. glutamate binding to the AMPA receptor makes cell permeable to K+ and Na+, but Na+ floods into post synaptic cell and causes small EPSP 4. long term potentiation across AMPA receptors (high frequency) cause significant enough depolarization for Mg2+ to detach from the AMDA receptor (20-30mV) 5. Ca2+ floods into postsynaptic cell and activates a 2nd messenger cascade - long-lasting increase in glutamate receptors and sensitivity - long-lasting increase in glutamate synthesis and release (via retrograde messenger)

Define diffusion

the movement of molecules from one area to another

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: 1. depolarizing stimulus 2. voltage-gated Na+ channels open, Na+ flood into the cell 3. PNa increases 4. Na+ flow continues to increase with more depolarization and more voltage-gated Na+ channels opening ---continues until Na+ channel inactivates the opening of K+ channels and membrane repolarization is an example of negative feedback: 1. depolarizing membrane due to Na+ influx 2. voltage-gated K+ channels open; allow slow flux of K+ out of the cell 3. Pk increases 4. K+ flow continues to increase out of the cell, cell repolarizes in the process 5. repolarization causes the K+ channels to slowly close

Explain why each eye has a "blind spot" and why we don't normally notice it

the optic disc on the nose side of the retina (when blood vessels enter and exit and ganglion cells exist) lacks photoreceptors so photons striking this region can't produce an image we don't normally notice it because the brain paints the "hole" to match the background

Define receptive field

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

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

the steady state that homeostasis maintains with constant energy input in the body is known as the set point value of a particular variable in a system; a set point might change in the case of a fever, where an elevated body temperature helps the body fight infection and in the case of elevated blood pressure during exercise, when the set point range changes it happens in the integrating center

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

usually only propagate in one direction because it starts at the end with the axon hillock, and the refractory period prevents it from reversing direction

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 which vary in number depending on the cell type