PBL(1L) Physiology

Physiology - Chapter 25 What is balanced during steady-state conditions? Primary means of up-regulating output? Aside from fluid, what else does the kidney alter to match input/output? Total amount of body water in a 70 kg adult? Two main compartments of the extracellular fluid? Non-cellular portion of the blood that mixes continuously with the interstitial fluid through capillary membrane pores? Excessive production of RBC's? Normal hematocrit for men and women? Plasma and interstitial are seperated by what, so their ionic compositions are very similar? Which one has a higher protein concentration, intersitial or plasma? What has low permeability to proteins and therefore leak only small amounts of protein? Intracellular is seperated from the ECF by what? What is the highly selective membrane permeable to? What is it not permeable to? Osmolarity and concentration of water are approximately equal in the what? What is different in the ICF and ECF? Can the volume of the ECF and ICF be measuered directly? ICF and ECF distribution is mainly determined by what, which acts across the cell membrane? Can Na+ and Cl- pass through the cell membrane? Concentration expressed as osmoles per kilogram of water? Concentration expressed as osmoles per liter of solution? Amount of water pressure required to prevent osmosis of water through a semipermeable membrane? What is directly proportional to the concentration of osmotically active particles in a solution? Small differences in the solute concentration across a cell membrane can result in? Solution in which NO osmotic force develops across a cell membrane when a normal cell is placed in solution? Example of isotonic solutions? Solution that contains a higher concentration of osmotic substances than does the cell? What happens to a cell placed in hypertonic solution? Solution that contains a lower concentration of osmotic substances than does the cell? What happens to a cell placed in hypotonic solution? Do osmolarities of the ICF and ECF stay different for very long? Cell membranes are impermeable to solutes, therefore - what stays relatively constant? Increased ECF osmolarity? Decreased ECF osmolarity? Net osmosis of water OUT of the intracellular fluid -> extracellular fluid Increase osmolarity of both compartments? Net osmosis of water INTO the intracellular fluid from the extracellular fluid? Increase in fluid volume of both compartments (Intracellular slightly more than ECF) Three conditions that are likely to cause INTRACELLULAR edema?

Sodium ions usually leak from where to where? What happens when they don’t get enough nutrition or the metabolic systems are depressed? What does the excess sodium cause? Has a direct effect on permeability of the membrane, allowing sodium to diffuse into the interior of the cells? What type of edema will this result in?

Fluid intake and output Renal excretion Electrolytes (Na+, Cl-, K+) 42 L Plamsa (1/4) and Interstitial Fluid (3/4) Plasma

Polycythemia 0.42 and 0.38, respectively Highly permeable membrane Plasma Capillaries A highly selective membrane Water Electrolytes found in the body ICF and ECF Concentrations of various solutes No, they are calculated from other compartments Osmotic Effect of Electrolytes No, but water can. Therefore, the concentrations of these solutes determine osmotic gradie Osmolality Osmolarity Osmotic pressure Osmotic pressure Rapid osmosis of water

0.9% sodium chloride and 5% glucose solution Hypertonic Shrinks Hypotonic Swells No, water moves rapidly across the cell membrane. number of osmoles, unless solutes are added to or lost from the ECF Hypertonic Hypotonic Hypertonic Hypertonic Hypotonic Hypotonic 1. Hyponatremia 2. Depression of the metabolic systems of the tissues 3. Lack of adequate nutrition to the cells Extracellular to Intracellular Na+ cant be pumped effectively out of the cell osmosis of water into the cells Inflammation Intracellular Edema

Increased intracellular ions will result in what? Two general causes of ECF edema? Increased capillary filtration coefficient allows what? When does this occur? Obstruction of veins, excessive blood flow from arteries to capillaries or failure of the heart to pump results in? Fail of liver to produce p. proteins, loss of large amounts of proteins, or severe burns results in? Lymphatic blockage, which prevents return of protein from interstitial to the blood results in? Plasma proteins leak into the intersitium but can't returnto the plasma via lymphatics in what disease condition? What will rise due to the increased interstitum plasma proteins? Increased intersitial colloid osmotic pressure will result in what? Infection with what can result in lymphatic edema? Three major safety factors that prevent edema?

Low compliance means? When Interstitial fluid volume increases, IFHP increases and opposes what? What is the safety factor (mmHg) for Low compliance? What is the safety factor (mmHg) for Lymph flow increases? With increased fluid volume, what happens to protein concentration? What does the decrease in protein concentration cause? Safety factor for protein "wash down"? Combind safety factor in mmHg? Capillary pressure could theoretically rise 17 mmHg without what occuring?

osmosis of water into the cells 1. abnormal leakage of fluid from the plasma to the interstital spaces around the capillaries 2. failure of the lymphatics to return fluid from the interstitium of the blood = lymphedema Increased leakage of fluids and plasma proteins through capillary membranes Allergic reactions, bacterial infections, and toxic substances that injure the capillary membr increase permeability Increased capillary hydrostatic pressure

Decreased plasma colloid pressure ( -> increase capillary filtration rate) Increased interstitial fluid colloid osmotic pressure ( -> draws fluid out of the plasma into th Lymphatic blockage

Intersitial collloid osmotic pressure Fluid drawn out of the capilliaries -> EC Edema Filarial Nematodes 1. Low compliance of tissues as long as interstitial fluid hydrostatic pressure is in the negat 2. Lymph flow can increase 10 - 50 fold 3. "Wash down" of interstitial fluid protein as lymph flow increases That small increases in interstitial fluid volume are assoicated with large increases in IFHP. Further exessive capillary filtration 3 mmHg 7 mmHg It is decreased, as it is washed away before it can be filtered lowers the net filtration force across the capillaries and tends to prevent further fluid accum 7 mmHg 17 mmHg Significant Interstital Edema occurance

Physiology - Chapter 26 Homeostatic functions of the Kidney?

Excretion of wastes and chemicals Regulate water and electrolytes Regulate body fluid osmolarity Regulate arterial pressure via water, AII, Renin, etc. Regulate acid/base balance via excretion of acids and buffers Regulation of D3

Physiology - Chapter 45 Fundamental unti of operation for the NS Much of NS activity arises from mechanisms that activate what? Sensory input can be stored in form of what? The brain compares new sensory information with stored memory information to develop what? At a termination site, axons give off many small branches that end in what? Synaptic Terminal is apposed to but seperated from an adjacent what? The narrow space between is called the what? Synaptic Boutons contain an abundance of what organelle? They also contain many synatpic vesicles which contain what? What happens when the NT binds to receptors on the postsynaptic membrane? Overwhelming majority of synapses in the brain are what type of synapses? Transmission of signals at chemical synapses is described as what?

Neuron Sensory receptors Memory Successful strategies to form motor output Synaptic terminals Post synaptic structure (either soma or dendrite) The synaptic cleft Mitochondria NTs Alters membrane permeability to ions Chemical One Way

Least common type of synapse in mammals is what? Electrical synapses consist of what? Why are these important? Why are these type of electrical synapses important? What happens after an action potential hits the presynaptic element? After the Ca2+ channels open, where does the calcium go? What does the ca2+ influx cause? The amount of vesicle release is proportional to the amount of what? Receptors are complex proteins that contain two things? Ionophores can be what? Most, if not all, receptors are linked to what? These ligand-gated channels can be? Post synaptic cationic channels that allow sodium to enter are usually? Post synaptic anionic channels that allow chloride to enter are usually? Second messanger activators are typically G-proteins attached to what? When the receptor is activated, a portion of it is released and moves within what? What does it do in the cytoplasm? (1 of 4 possible things)

Small-molecule, rapidly acting transmitters can be synthesized and packed into what? SmNT have _______ action and usually act open or close an ion channel. Aside from this action, they can activate enzymes to alter what? Where are smNT recycled? Acetyl CoA and Choline yeild what? What is the enzyme necessary to synthesize ACH? Where is ChAT synthesized? What breaks down ACH? Where is AChE present? Choline is transported back to where for reuse? Transmitter agents that are typically synthesized in the Soma as integral parts of large proteins? Are larger or small amounts of neuroactive peptide released, as compared to smNT? Are vesicles for neuroactive peptides recycled An important feature of neuropeptides is what? What can neuropeptides do? Neuronal resting membrane potential? Move to a MORE POSITIVE value is also called what? Move to a MORE NEGATIVE value is also called what? Depolarization makes the cell more/less excitable? At rest, excellular sodium is higher/lower than intracellular? At rest, excellular potassium is higher/lower than intracellular? The electrical potential that opposes movement of that ion down its concentration gradient? Nerst potenital for sodium Would you expect sodium to move in or out with a resting membrane potential of -65 mV? Some does leak in however, and potassium leaks out - what corrects this? Neuronal membrane is maintained at -65 mV b/c it is much more permeable to ? Thus, the interior of the cell is negatively charged and outside it become what? The interior of the soma consits of what that allows changes in potential to spread throughout the neuron? Ligand-gated channel open, Na+ out of cell -> potential in terminal moves closer to +61 mV,

The electrical synapse Gap junctions They form low resistance channels between the pre and post synaptic membranes Ions can move freely and this allows rapid transfer of signals that can spread through large neurons Ca2+ channels open It moves into the axon terminal Synaptic vesicles to move/fuse with the membrane and be released Ca2+ influxR 1. Binding Domain 2. Ionophore (extends through the membrane, into the interior of the post synaptic structur Ion specific channel or second messanger activator Ligand-gated ion channels Cationic or Anionic Excitatory Inhibitory A portion of receptor that protrudes into the postsynaptic element The cytoplasm 1. Opens membrane channel specific for an ion species (Na or K) and keeps it open 2. Activates cAMP or cGMP -> specific metabolic machinery 3. Activates enzymes -> biochemical reactions 4. Activated gene transcription -> protein synthesis -> long-term changes Synaptic Vesicles rapid Metabolism in the postsynaptic element Axon Terminal ACH Choline Acetyltransferase Soma and delivered to the bouton via axonal transport AChE Cleft Synaptic Bouton Neuropeptides Smaller amounts No Prolonged duration of action Alter ion channel function and modify cell metabolism or gene expression -65 mV Depolarization Hyperpolarization More Higher Lower Nerst Potential +61 mV In, but it can't because the channels aren't open Na/K pump K Positively charged hightly conductive fluid EPSP (excitatory post synaptic potential)

called? Action potential initated at? Why would it be initiated there? Simulaneous discharge of many axon terminals is required to bring post synaptic element to threshold, called? Basis of production for an inhibitory postsynaptic potential (IPSP) Nernst Potential for chloride? This is more negative than resting potential so chloride would be expected to do what? Occurs when a second postsynaptic potential arrives before the membrane has returned to resting potential? Occurs when a number axon terminals over the surface of a neuron are active simultaneously? At any given time, the neuron is combining all the IPSPs and Dendrites contain a relatively small number of voltage gated channels and therefore are not able to what? However, they can do what? This mode of tranmission is subject to what? Therefore synapses on proximal dendrites have more what than distal? Firing rate of a neuron is directly related to ? Rapid, repetitive stimulation of a synapse will lead to what Fatigue will cause what to happen? The decrease in responsiveness is the direct result of what? Repetitive stimulation + excitatory neuron after brief rest period = requires less current and produces more response More acid EC synaptic environments will cause what to happen to excitability (decrease pH)? Decrease in the supply of oxygen will cause what? Increases the excitability of many neurons? Indirectly increases the activity of neurons by inhibiting certain populations of inhibitory neurons? Amount of time to cross the synapse that varies in different pools of neurons? Synaptic delay is influenced by?

Initial segment Region contains approx. seven times the number of voltage gated channels Summation NTs that open Cl- gated channels -70mV move into the cell Temporal Summation Spatial Summation EPSPs Propogate action potentials

Support the spread of electrical current via electrotonic conduction Decay over time Influence over action potentials the degree by which the threshold is exceeded (the farther above, the greater the firing rat Fatigue decreased responsiveness increased build up of ca2+ in the bouton and inabilty to replenish the NT Post-tetanic Facilitation Decreased Excitability Decreased Synaptic Activity Caffeine Strychnine Synaptic Delay 1. Time required to release NT 2. Time need for NT to diffuse across 3. Time needed for binding of NT to receptor 4. Time needed for NT to carry out its action 5. Time required for ions to diffuse into the PostS cell and alter membrane potential

Physiology - Chapter 46 Responsible for tast and smell, O2 and CO2 levels in blood, and osmolarity of tissue fluids? Sensory is convey to the spinal cord using a ______ ____ approach? They are basically all conveyed the same/differently? What does allow us to differentiate pain from some other sensation, is where it? Action potentials in the spinothalamic tract are perceived as? Action potentials in the dorsal column-medial lemniscal system are perceived as? Local current generated at the receptor when activated by the appropriate simulus is called? The maximum receptor potential amplitude of about 100 mV is achieved when membrane Na+ is at its? When is a self propogating action potential initiated in the fiber? Receptor potential is proportional to the? As stimulus intensity increases, the action potentials will increase in Sensory receptors can ____ to their stimuli? Compression anywhere on the pacinian corpuscle will cause what? Any type of change in the central fiber leads to what? The fluid will redistribute within the corpuscle in response to the what

Chemoreceptors Labeled Line Same, action potential from pain is the same as action potential from temperature Terminates in the NS Pain Touch or pressure Receptor Potential Maximum When the receptor potenital exceeds a set value Stimulus intenisty frequency adapt Indentation, elongation, or defromation of the central fiber Increase in membrane permability Applied pressure

A process that may involve the gradual inactivation of the sodium channels over time? Continue to transmit signals with little change in frequency so long as the stimulus is still present? Another name for slowly adapting fibers? Examples of Tonic Receptors?

Activated only when stimulus intesity changes? Other names for these rapidly adapting fibers? Example of Rapidly Adapting?

Typical large and myelinated fibers of the spinal nerves? Small unmyelinated nerve fibers that conduct impulses at low velocities? Largest and most rapidly conducting fiber? Fibers from the golgi tendon organs? Weak stimulus excites a small/large receptive field? Any aggregate of neurons can be referred to as what? Each neuronal pool has set of several inputs to its _______ _____ membrane potential that is slightly depolarized but not enough to reach threshold? Are these fibers more or less excitable and why? Input signal spreads to an increasing number of neurons as it passes through successive orders of neurons in its path? What pathway utilizes this type of amplifying divergence? Signal is transmitted in two directions from the pool? Example of diverenge into multiple tracts? Results when multiple afferent sources reach a single neuron in the pool? Can also have convergence on a single neuron from ? One of the most important ways that the CNS correlates, summates, and sorts different types of information? While moving flexors, inhibiting extensors? Prolonged output discharge is called? Positive feedback to re-excite the input of the same circuit is called? Some neuronal pools generate a rhythmical output signal, one example of this would be? When the carotid body is stimulated by arterial O2 deficiency…? Two main mechanisms to inhibit seizures or uncontrolled firing of neuronal circuits? With feedback inhibition, output signals what located in the pool to provide inhibitory feedback to the main output? Exerts inhibtory influences throughout the muscle control system?

Accomodation Slowly adapting fibers Tonic Receptors Golgi Tendon Organs Pain Receptors Baroreceptors Chemoreceptors Rapidly adapting fibers Rate Receptors and Movement Detectors Pacinian Corpuscle Receptors of the Semi Circular Canals Joint Receptors (proprioceptors) Type A Type C Type Aα Group 1b (Type Aα) Small a neuronal pool Receptive field Facilitated More, they require less depolarization to reach threshold Amplifying divergence Corticospinal Tract Divergence into multiple tracts Dorsal column -> Cerebellum and Lower Brain Convergence Multiple sources Convergence

Reciprocal Inhibition Circuit Afterdischarge reverbatory Respiratory centers in the reticular formation of the medulla Both the frequency and amplitude of the respiratory rhythmical output signal increase prog Inhibitory circuits and fatigue of synapses Inhibitory Interneurons Basal Ganglia

Physiology - Chapter 47 Includes both tactile and position sensations? Detects increases or decreases in temperature? Detects tissue damage or the release of specific pain-mediating molecules? Sensations that originate from stimulation of body surface structures (skin and sub c tissues, muscle, fasica, tendons)? Sensory signals that arise from internal organs (endodermally derived structures)? Touch, pressure, vibration are each detected by what general class of tactile receptors? Found in varying density in all areas of the skin (as well as cornea of the eye)? Encapsulated, rapidly adapting receptor found in non-hairy areas of skin (fingertips) - senitive to lighest touch?

Mechanoreception Thermoreception Nociception Exteroceptive Visceral Sensations Mechanoreceptors Free Nerve Endings Meissners' corpuscle

Found in glabrous skin but are also present in moderate numbers in hairy skin surfaces, slow adapting - continuous touch? Entwined at base of each hair, rapidly adapting, detect movement of objects over the skin that displaces hair? Encapsulated, located at skin and deeper tissues and joint capsules, little adaptation - signal continous touch/movement? Present in the skin and deeper tissues, such as fascia - Adapt rapidly, important for vibration and mechanical change? Most of these receptors transmit signals over what type of fibers? Are linked to small myelinated fibers and unmyelinated type C fibers that conduct at slow velocity? Detect the most rapid change in vibration - linked to large, myelinated fibers? Sense of tickle or itch is linked with what type of receptor? Signals that orgininate in the thermoreceptors and nociceptors are processed along what system? Signals that originiate in the mechanoreceptors are processed along what system? Somatosensory information for the face is carried mainly along branches of what nerve? Some of the DC-ML fibers enter the SC and synapse in the? Most of the DC-ML fibers enter the SC and do not synapse until they travel upward and reach what? Where is the dorsal column nuclei located? Lower extremity fibers synapse in what part of the dorsal column nuclei? Upper extremity fibers synapse in what part of the dorsal column nuclei? Axons of the cuneate and gracilis form what? Where does the medial lemniscus cross the midline? Where does the bundle travel next? Where do the axons then terminate? Axons of the VPL neurons then enter the posterior limb of the? From the internal capsule, where do these axons then project? Information for the LE travels in what part of the dorsal column? Information for the UE travels in what part of the dorsal column? LE information terminates in what part of the VPL? UE information terminates in what part of the VPL? LE information then travels to what part of the SI? UE information then travels to what part of the SI? Tacticle somatosensory information travels from the fact through what nerve? Where does CN V enter the BS? Where does CN V terminate in the BS? Axons from CN V cross the midline, course rostrally, and terminate where? LE projects toward the _______ part of the hemisphere in the SI? UE projects toward the _______ part of the hemisphere in the SI? Most characteristic of the six horizontally arranged layers of the cortex? Why is the the most characteristic layer? In the most anterior part of area 3 in the SI, the vertical columnar arrays are concered with what? In the most posterior part of area 3 in the SI, the vertical columnar arrays are concerned with what? In area 1, the verical columnar arrays process what? In area 2, the vertical columnar arrays are concered with what? Lesions that involve the primary somatosensory cortex result in:

Lesions that involve Brodman's Area 5 and 7 (assoication cortex for somatic sensation) result in:

Merkels' discs Hair end-organs Ruffini's end-organs Pacinian corpuscles Large, myelinated fibers that exhibit rapid conduction Free Nerve Endings Pacinian corpuscles Free Nerve Endings Anterolateral Dorsal Column-Medial Lemniscal Trigeminal Gray Matter Dorsal Column Nuclei Caudal Medulla Nucleus Gracilis Nucleus Cuneatus Medial Lemniscus Caudal Medulla Thalamus VPL (Ventrolateral Posteior Nucleus) Internal capsule Primary Somatosensory Cortex (Postcentral Gyrus) Medial Lateral Laterally Medially Medial Part of the SI Arm section of the SI (contralateral to the body) Trigeminal Midpontine Levels Trigeminal Sensory Nucleus VPN (Ventral Posteriomedial Nucleus) Medial Mid-Lateral Layer IV Receives the important projections from VPL and VPM of the ventrolateral thalamus Muscle Afferents Cutaneous Input

Additional Cutaneous Input Pressure and Proprioception 1. Inability to localize cutanous stimuli on the surface of the body (crude localization may re 2. Inability to judge degree of pressure or weight of objects 3. Inability to identify objects via touch or texture 1. Inability to recognize objects that have complex shape when palpated with contralateral 2. Loss of awareness of the contralateral side of the body (hemineglect) - most acute with l non-dominant parietal lobe

Determined by the combination of primary sensory neurons, dorsal column nuclear neurons, and thalamic neurons? Used to determine and individuals ability to distinguish two simultaneously applied cutaneous stimuli as separate? Where can two stimuli be applied close together and still felt as 2 sepearte points with no overlap? How far apart must two stimuli be to be felt as separate points on the back? Mechanism used throughout the NS to "sharpen" signal transmission? Where does lateral inihibition occur in the DC-ML system? Particularly sensative for detecting rapidly changing repetitive stimuli (basis for vibartory sense)? Awareness of body position or body movement is called what? Combination of what is used by the NS to produce a sense of proprioception? What type of endings are rapidly acting receptors responsible for detecting the rate of change in movement? What accounts for the DC-ML ability to localize stimuli fairly well? What accounts for the less effective localization ability seen in the anterolateral system? Different Characteristics of the Anterolateral System, compared to the DCML?

Anterolateral system transmits what type of sensations?

3. Exploring an object, only touch the side that is ipsilateral to the lesion, ignore the contra side (amorphosynthesis) Receptive field for an SI cortical neuron Two-point discrimination test Lips and Fingertips 30-70 mm Lateral Inhibition At the level of DC nuclei and in the thalamic nuclei DC-ML (Pacinian and Meissners) Proprioception Combination of tactile, muscle, and joint capsule receptors Ruffini's end-organs Point-to-point organization Relative diffuseness 1. Velocity of transmission is approx. 1/2 that of the DCML 2. Degree of localization is poor 3. Gradations in intestity are far less pronounced 4. Ability to transmit rapid repetitive signals is poor Pain, Temperature, tickle, itch, crude touch, and sexual sensations

Physiology - Chapter 48 Protective mechanism for the body? Not just a sensation but a response to tissue damage? Felt within 0.1 sec after stimulation? Begins 1 second or more after the painful stimulus? Usually associated with tissue damage? Slow pain can be referred as what? All pain receptors are what? Found in the largest density where? Activated by mechanical, thermal, or chemical stimuli? Mechanical and Thermal stimuli tend to elicit what? Chemical stimuli tend to elicity what? What two chemical stimuli enchance the sensitivity of pain receptors but do NOT excite them? Items that excite the pain receptors? Pain receptors adapt very quickly/slowly/ or sometimes not at all? Activation of these receptors can become progressively greater as the pain continues, what is this called? Fast pain trasmitted over what type of fibers? Slow, chronic type of pain transmitted over what type of fibers? Aδ primiarly excite neurons in lamina ___ of the dorsal horn? Wheras, C fibers synapse with neurons in the? From the Substania Gelantinosa -> deeper into gray matter -> active neurons in what lamina(s)? Neurons that receive Aδ give rise to the? Neurons that receive C give rise to the? Neospinothalamic Tract axons cross the midline where? NST ascends what of the SC as part of the anterolateral system? Where do some of the NST fibers terminate in the BS? Where do the majority of the NST fibers terminate?

Pain Pain Fast Pain Slow Pain Slow Pain Burning, aching, or chronic pain Free Nerve Endings Skin, periosteum, arterial walls, joints, dura, and cranial vault Pain receptors Fast Pain Slow Pain Substance P and prostaglandins Bradykinin, serotonin, histamine, potassium, acids, ACH, and proteolytic enzymes Slowly Hyperalgesia Aδ C I Substania Gelatinosa Mainly V, but also VI and VII Neospinothalamic Tract Paleospinothalamic Tract Close to their origin White matter Reticular Formation VPL of the thalamus (from here they project to the SI cortex)

Which the phylogenically older of the two pain systems? Pathway for the PST (after cross midline near origin and anterolateral ascention)?

Paleospinothalamic Tract Terminate in BS -> fibers from BS (reticular) -> intralaminar nuclei and posterior nuclei of th and to the hypothalamus