EXAM 1 PGY412

________ is the hematocrit in a normal XY subject

45%

Which of the following is a key principle of physiology? a. Physiological variables are fine tuned by mechanisms that work in opposition of one another b. All options are correct c. Organ systems work independent from one another to prevent system-wide failures d. Evolution selects for function, because body parts with analogous functions lack structural convergence e. Homeostatic mechanisms are closed loops that amplify physiological responses

A

_____________ are a common mechanism to regulate physiological processes

feedback loops

Neurons

initiate, integrate, and conduct electrical signals to other cells (PNS vs. CNS)

Circadian rhythms are ___________ driven rhythms that cycle approximately once a day and ____________ factors set the timing of these rhythms

internally environmental

Diffusion of Ions Across a Membrane

ions (Na+, Ca2+, K+, Cl-) permeate the membrane through ion channels via *integral membrane proteins* that form aqueous pores -*diameter of pore and its surface specifies ion selectivity* (I.e. Na+ vs. K+ channels)

__________ can target a variety of proteins leading to rapid and slow cellular responses and _________ signals undergo application through phosphorylation

kinases second messenger

% of ligand-bound receptors depends on ________________ and competitors ___________ the % bound at a given concentration

ligand concentration and affinity of receptor for ligand lowers

Plasma

liquid portion of the blood and has more protein than the interstitial (tissue) fluid

Chemical messengers participate not only in reflexes but also in ____________ responses

local *hormones & neurotransmitters*

The higher the osmolarity, the ____________ the water concentration

lower

____________________ is proportional to concentration difference, membrane surface area, and ease with which a molecule crosses the membrane (termed _______________)

net flux permeability

Homeostatic balance depends on relative rates of ____________ and ____________

net gain and net loss

Which is one of the four basic cell types: immune, cardiac, respiratory, neuron

neuron

_____________ affect neuron or effector cell in close proximity to site of release

neurotransmitter

____________ molecules diffuse rapidly through lipid membranes

non-polar (O2, CO2, fatty acids, steroid hormones)

Steady State

particular variable ([X] between left and right compartments) is not changing but energy is continuously added to maintain constant condition

Resetting Set Points

phase shift: resetting the internal clock that drives circadian rhythms (i.e. jet lag) fever in response to infection (body temp greater at all points throughout the day compared to reg. temp)

Homeostasis

principle for maintaining internal stability *ICF <-> ISF <-> plasma <-> organs <> external environment*

Plasma is different form interstitial fluid because it has a lot of _____________

protein

Local Response

sequence of events occurs only in area of stimulus

Glucose works as a __________________ solute

slowly penetrating

Hematocrit

the percentage of the volume of RBC compared to total blood (RBC + plasma) [RBC (v)/ (RBC (v) + plasma (v)] x 100

Pool concentration of body substances depends on ___________________________ and the ________________, each of which is subjected to control by nervous and/or endocrine systems

total amount exchanges within the body

Epithelial Transport Pathways

*Transcellular pathway:* movement into a cell, through the cytosol, and exit across the opposite membrane *Paracellular Pathway:* diffusion between adjacent cells, limited by tight junctions that form a seal around apical end

Extracellular Matrix (ECM) Functions

- provides a scaffold for cellular attachments -transmits information (chemical messengers) to the cells to regulate their activity, migration, growth, and differentiation

Primary Active Transport

- the Na+-K+-ATPase is primary active transporter food in every cell and helps establish and maintain the membrane potential of the cell -other primary active transport proteins found in most cells are Ca2+-ATPase, H+-ATPase, H+-K+-ATPase

Using K+ and Na+ as example, explain how energy is used to maintain homeostasis

-ICF [K+] is ~30x more concentrated than ECF [K+] -ICF [NA+] is ~10x less concentrated than ECF [Na+] -cells expand energy (ATP) to "pump" these ions against their concentration or chemical gradient (Na+K+ATPase) -the net [K+] and [Na+] concentrations do not change over time, the system is at *steady state* (energy is added to continuously maintain constant condition)

Transport Proteins

-also called carriers -transport molecules too large or polar to directly diffuse across the membrane -specific or their ligand and can saturate (I.e. a max flux of molecules that can be reached)

Negative Feedback

-closed loop in which the end product inhibits the production of initial stimulus -usually controlled by endocrine or nervous system -shuts the system off once the set point has been reached

Principles of Physiology

-deals with physical and biochemical function of human body -requires the *integration* of knowledge at multiple levels: cellular, tissue, organ, organ system, and whole body -applied knowledge can help maintain, prolong, and improve quality of human life

Net Flux

-difference between the two one-way fluxes -depends on (1) temperature, (2) molecule mass, (3) surface area, (4) medium through which molecules move

Extracellular Fluid (ECF)

-fluid present in blood (plasma) and in spaces surrounding cells (interstitial fluid) -fluid *outside* the cell 33% total body fluid; 7% plasma, and 26% ISF

Homeostasis with Glucose

-glucose molecules are enzymatically broken down to release chemical energy -this energy is stored in the bonds of ATP and is utilized by *ATPase* to power a large number of cell functions

Kinase vs. Phosphatase

-kinase: adds a phosphate group (cause phosphorylation usually by ATP hydrolysis converting ATP to ADP + P) -phosphatase: removes a phosphate group

Connective Cells

-mass of extracellular proteins that connect, anchor, and support structures of the body -loose meshwork, tendon/ligaments, bone, cartilage, blood cells, fat

Explain the movements of molecules in diagram below:

-molecules move at a result of random thermal motion which will eventually distribute the molecules uniformly in compartments 1 & 2 (equilibrium) -oxygen nutrients and other molecules can move across by simple diffusion

Specialized Cell Types

-muscle cells -neurons -epithelial cells -connective tissue cells

Osmosis

-net diffusion of water across a membrane -facilitated by channel proteins called aquaporins (expression and insertion of these varies among cell types)

Methods of Inhibiting Signal Transduction Pathways

-phosphorylation of receptor -Internalization of receptor (endocytosis) -decrease signal/local signal concentrations (breaking down first messenger)

Lipooxygenase Pathway

-production of leukotrienes -stimulated by phospholipase A2 activating arachidonic pathway -Important in inflammatory response

Cyclooxygenase Pathway

-production of prostagladins and thromboxanes -stimulated by phospholipase A2 activating arachidonic pathway -Important in inflammatory response

Epithelial Cells

-provide protective cover for the body -provide barriers for selective secretion and absorption of ions and organic molecules -polar [apical vs. basolateral]

Tonicity

-reflects a solution's effect on cell's volume -Involves mOsm of non-penetrating solutes (solutes that cannot cross plasma membrane or behave like one)

Cell Membrane Function

-regulates the passage of molecules in and out of cells -detects chemical messengers at cell surface

Lipid Bilayer Barrier

-small hydrophobic molecules can pass the lipid core -other molecules transit the membrane via channels, carriers, or vesicles

Cross Talk

-the interactions of signal transduction pathways -one or more pathways may be active simultaneously in a single cell, undergoing complex interactions -may alter signals of other pathways (active molecules generated in cAMP pathway can alter receptors and signaling molecules generated by other pathways" -pathways can be shut off due to *cessation* of receptor activation

Secondary Active Transport

-uses electrochemical gradient as its energy source -transporters have 2 binding sites, one for ion (I.e. Na+) and another for co-transported molecule (I.e. glucose) -use co-transporters (symporters & antiporters) and counter-transporters (anti porters)

Active Transport

-uses energy to move molecules against the concentration gradient -often called *pumps* -can also be saturated

One osmol = ________ mol of solute particles

1

1 M solution of sucrose = ____ Osm (osmol per liter) 1 M solution of NaCl = ____ Osm 1 L of solution containing 1 mol sucrose and 1 mol of NaCl has ____ Osm

1 2 3

One night patient X went to the University Hospital emergency room saying that they were dehydrated. The attending physician gave patient X, an intravenous infusion of 1.0 L of distilled water. Analysis of patient's X blood showed that before the infusion the plasma osmolarity was 300 mOsmoles/L. 1. Calculate patient's X plasma osmolarity immediately after the infusion of water (assume the patient had 3L of plasma and no mixing with interstitial fluid or RBC) 2. if patient X RBC was 300 mOsm/L and they had 2L of RBC, what was the plasma and RBC osmolarity after the water equilibrated (assume no mixing with ISF)? 3. what is the new volume of the plasma and RBC?

1. (300mOsm/1L) x 3L = 900 mOsm plasma 900mOsm/(3L + 1L) = *225 mOsm per L* 2. (300mOsm/1L) x 2L = 600 mOsm RBC (600 mOsm + 900 mOsm)/ (3L + 2L + 1L) = *250 mOsm per liter* 3. 600mOsm x (1L/250 mOsm) = 2.4 L 900 mOsm x (1L/250 mOsm) = 3.6 L 2.4 L + 3.6 L = *6 L*

Energy Sources of Active Transport

1. ATP in primary active transport 2. electrochemical gradient across a membrane for secondary active transport

Which panel (A-D) corresponds to which osmolality? 1. _______ 100 mOsm 2. _______ 200 mOsm 3. _______ 300 mOsm 4. _______ 400 mOsm

1. B 2. C 3. D 4. A

Ca2+ and Calmodulin Mechanism

1. Ca2+ enters via cell membrane channel or from release from ER 2. upon binding with Ca2+, calmodulin changes shape 3, this allows calcium-calmodulin to activate or inhibit a large variety of enzymes and other proteins, many of them protein kinases

GPCR (Gi, Inhibitory) Mechanism

1. activation of Gi 2. inhibition of adenylyl cyclase 3. decrease the concentration of cAMP in the cell 4. turns off PKA decreasing in phosphorylation of key proteins inside the cell

Guanylyl Cyclase (Cytosol or Receptor Enzymes) Mechanism

1. activation of membrane bound guanlyl cyclase receptor by first messenger (natriuretic peptides) 2. conformational change of the receptor 3. cGMP production 4. cGMP protein kinase 5. phosphorylation of many target proteins

Ligand-Gated Ion Channels Mechanism

1. activation of receptor by a first messenger (ligand) 2. conformational change of the receptor 3. opening of ligand-gated ion channels 4. increase in net diffusion of one or more specific ions across the plasma membrane 5. change in membrane potential

GPCRs Mechanism

1. activation of receptor by first messenger (ligand) 2. conformational change of the receptor 3. G protein dissociation (alpha and beta-gamma) 4. ion channel and second messenger signaling (cAMP, PI3, Ca2+) *Most numerous type of receptor family and have large variety of signaling pathways associated with them*

Assume an artificial cell. It has been created to have exactly the same composition as human intracellular fluid but its artificial membrane is permeable only to water. When this artificial cell is placed in a ______ solution consisting of 25 mM CaCl2 + 50mM NaCl + 25mM sucrose, the cell would ___________. A. hypotonic : swell and burst B. hypotonic : shrink C. isotonic : maintain the same volume D. hypertonic : swell and burst E. hypertonic : shrink

A

Titin molecules run from the Z-lines to near the M-line within a sarcomere. They: A. are only found in slow-oxidative fibers B. are ~1 um long C. directly influence duration of Ca2+ transient D. help to minimize muscle fatigue

B

Vasodilation is caused by an increase in CGMP in the smooth muscle cell. In the smooth muscle of the renal arteries, a small gases molecular, nitric oxide (NO), can directly bind and active cytosolic guanylyl cyclase leading to vasodilation. Atrial Natriuretic Peptide (ANP), a large hydrophobic protein hormone from the heart, also causes vasodilation of renal arterioles. This is possible because ANP directly binds and activates: A. the intracellular receptor with the guanylyl cyclase activity in the smooth muscle B. the membrane receptor with the guanylyl cyclase activity in the smooth muscle C.. the phosphodiesterase that degrades cGMP in the smooth muscle D. the cytosolic guanylyl cyclase in the smooth muscle

B

Voltage gated calcium channels have been inhibited and an AP initiated in neuron 4 of the diagram above. Which of the following is correct? A. neurons 5 and 6 will fire an AP B. Neither neurons 5 or 6 will fire an AP C. only neuron 5 will fire an AP D. only neuron 6 will fire an AP

B

When a chemical messenger functions in an endocrine fashion, it much have: A. a stimulated transcription in target cells B. activated receptors in a target cell after being transported in the blood C. activated receptors in a target cell after being transported in the blood D. activated adenylyl cyclase in target cells

B

Which of the following major cell type categories do blood cells belong to? a. neurons b. connective cells c. epithelial cells d. muscle cells

B

Your alarm goes off and, half asleep, you step out of the bed and stand on a push-pin in your bedroom. Which of the following is the CORRECT sequence of events? A. afferents travel to the primary sensory cortex, which signals to the primary motor cortex, which sends efferents to the legs to withdraw the foot B. afferents travel to the ipsilateral spinal cord, synapse onto interneurons which project to efferents on both the ipsilateral and contralateral sides to withdraw the foot C. afferents travel to the ipsilateral spinal cord, where they synapse onto efferent motor neurons projecting to the contralateral muscle for withdrawal of the foot

B

The vestibular system signals changes in body position in respect to the environment. Angular acceleration involves the _____ whereas lines acceleration involves the _____. A. saccule : semicircular canals and utricle B. utricle : semicircular canals and saccule C. semicircular canals : utricle and saccule

C

Which definition BEST describes "tissue"? a. The simplest structural units into which a complex multicellular organism can be divided b. The component of an organ that performs a specialized function c. Aggregate of differentiated cells with similar proteins d. Two or more aggregates of different types of differentiated cells that form tubes, layers, bundles, or strips

C

Which of the following best describes the entry of LDL, a large hydrophilic lipoprotein complex, into a steroid producing cell? A. LDL passively diffuses through the phospholipid cores into a steroid producing cell B. LDL passively diffuses into a steroid producing cell by pinocytosis C. LDL centers a steroid producing cell via receptor mediated endocytosis D. LDL is passively taken in by facilitated diffusion via LDL transporters

C

Which of the following explain the increased gastric and pancreatic secretions that occur after a large meal? A. increased secretion is due to inhibition of muscarinic receptors B. increase secretion is due to activation of adrenergic receptors C. increased secretion is due to parasympathetic stimulation D. increased secretion is due to sympathetic stimulation

C

An increase in plasma H+ ion concentration causes an increase in the firing of peripheral neurons called chemoreceptors. This activates medullary respiratory neurons to increase contractions of respiratory muscles to cause hyperventilation. The hyperventilation helps to lower the plasma H+ ion concentration to normal. Which one of the following is the EFFECTOR(S) in this reflex loop? a. Chemoreceptors b. The normalization of plasma H+ concentration c. Medullary respiratory neurons d. High plasma H+ ion concentration e. Respiratory muscles

E

Types of Peptides that Serve as First Messengers in Guanylyl Cyclase Mechanism

atrial, brain, and C-type natriuretic peptides

____________ substance acts on same cell that secreted the substance

autocrine

Physiology includes the study of ________, __________, and __________ to understand whole body function

cells organs organ systems

ECM proteins consist of ___________ which are ____________________.

fibers ropelike collagen and rubberband-like elastin and a mixture of non-fibrous proteins that contain carbohydrates (sugars)

Intracellular Fluid (ICF)

fluid located *inside* the cells 67% total body fluid

Muscle Cells

generate mechanical force (skeletal, cardiac, and smooth muscle)

G protein is a __________________ protein with ______, ________, and ________ subunits. The ______ subunit is bound to GDP

heterotrimeric alpha, beta, gamma alpha

___________ target cells in one or more distant places in the body

hormone

Receptor

on or in a cell, a specific protein to whose shape fits that of a specific molecular messenger, such as a hormone counter part of a ligand

Organ Systems

organs working together to perform a certain function (i.e. urinary system)

___________ substance targets cells in close proximity to site of release

paracrine

Enzyme Receptors Examples

receptor tyrosine kinases including insulin receptor, growth factor receptors

______________ are gate-keeps of a cell's responsiveness to ligands

receptors

Intracellular Receptors

receptors located inside the cell in cytosol or nucleus and bind to *lipophilic ligands* (steroids, thyroid hormones, estrogen, retinoid acid, androgen, etc) ligand binding induces conformational change of receptor leading to *alter in gene transcriptional activity* slower but sustained responses

Transmembrane (Integral) Receptors

receptors on membrane that bind to large, hydrophilic molecules (peptide hormones, amino hormones) that cannot enter the cell through the lipid bilayer binding of ligand leads to conformational change of receptor and cellular responses involving in many cellular proteins (*phosphorylation*) faster but less sustained

Body Fluids

refers to the watery solution of dissolved substances (ions, oxygen, nutrients, etc.) (includes ECF & ICF)

Membrane Potential

separation of electrical charge that exists across a membrane

Physiology

the branch of biology that investigates cellular, organ, organ system function and includes the study of individual molecules to *integrative* function of several organ systems

Set Point

the steady state condition where the variable is not changing (ion concentration, blood glucose levels, body temperature, etc)

Osmolarity

the total solute (and water) concentration

Goal of Physiology

to understand how living things and the *whole* body function and to understand how the body works and adapts to normal & abnormal activity, stresses, and disease

Epithelial cells are involved in many types of ___________ processes

transport

Ca+ binds to various cystolic proteins, altering their conformation and thereby activating their function. Some of these proteins include:

troponin, nitric oxide synthase, and PYK2 tyrosine kinase

Pathophysiology

certain disease defined by loss of homeostasis in one or more systems

Feedforward

changes in regulated variables are anticipated before they occur (e.g. temperature - sensitive neurons in the skin activate feedback before drop in body temp)

Ligand-Gated Ion Channels and Receptors Examples

channels: Na+, K+, Ca+ channels receptors: acetylcholine, AMPA, NMDA receptors

Ligands and receptors interact because of ______________ and ______________

charges shapes *specificity*

Ligand

chemicals (hormones, neurotransmitters, local messengers)

Ion channels exist in __________ or _________ conformations and ________ is the process of transitioning between the two

closed open ** pic

Organs

comprised of two or more tissues organized into smaller functional units (i.e. nephron)

Transport across a membrane occurs by __________________

conformational changes

Paracellular Transport of Osmosis with Na+ Diffusion

coordination of solute and solvent transport through epithelial cells: transcellular transport of Na+ from the lumen side to the blood side leads to an increased water transport by osmosis through both membrane aquaporins and paracellular passage

___________ inhibits phospholipase A2

cortisol (anti-Inflammatory hormone)

Positive Feedback

counter to general homeostasis because positive feedback accelerates a process leading to an "explosive" system (less common)

Janus Kinase Associated Receptor Examples

cytokine receptors, growth hormone receptors, prolactin receptors

Soluble guanylyl cyclase enzymes are present in the ____________ ____________ is a first messenger and diffuses into the cell and combines with guanylyl cyclase there to trigger the formation of cGMP

cytosol nitric oxide

Cellular Communication Pathways

endocrine, neuronal (neuroendocrine), paracrine, autocrine

___________ is an indicator of whole-body homeostasis

blood

GPCR (Gq) Mechanism

1. activation of the receptor by a first messenger 2. conformational change of the receptor 3. increases alpha subunit affinity for GTP 4. alpha dissociates from beta-gamma and activates *phospholipase C (PLC)* 5. breakdown of a plasma membrane phospholipid known as phosphatidylinositobisphosphate *(PIP2)* to diacylglycerol *(DAG)* and inositol tri-phosphate *(IP3)* 6a. DAG directly activates PKC (many types) 6b. Ca2+ release from endoplasmic reticulum via IP3 binding to IP3 receptor --> Ca2+ can activate PKC or initiate direct cell response

GPCR (Gs, Stimulatory) Mechanism

1. activation of the receptor by a first messenger (I.e. epinephrine) 2. conformational change of the receptor 3. increases alpha-subunit affinity for GTP 4. alpha dissociates from beta-gamma and activates *adenylyl cyclase* 5. cAMP is bound 6. cAMP-dependent protein kinase (PKA) activated 7. phosphorylation of many target proteins 8. diverse cellular responses

Janus Kinase Associated Receptor Mechanism

1. activation of the receptor by a first messenger (ligand) 2. conformational change of the receptor 3. recruit and activate Janus kinase (JAK) 4. JAKs phosphorylate target proteins including *transcription factors* 5. synthesis of new proteins

Enzyme Receptors Mechanism

1. activation of the receptor by a first messenger (ligand) 2. conformational change of the receptor and activation of enzymatic activity (cytoplasmic side) 3. autophosphorylation of receptor creates docking sites for other proteins 4. docking proteins then bind and activate other proteins (many types including kinases, RAF, MEK, MAPKK, etc. )

In glucose transport from epithelial cells to blood vessels... 1. ______ transports glucose into the cell 2. _______ acts as extracellular protein later 3. __________ transports glucose out of the cell 4. __________ blocks paracellular route

1. apical membrane 2. basement membrane 3. basolateral membrane 4. tight junction

After eating a meal, blood glucose levels cause beta cells in the pancreas to release insulin. Insulin acts on muscle, liver, and fat cells to take up glucose and return blood glucose levels to set point levels. Identify the role of the following in blood glucose homeostatic pathway: 1. insulin 2. blood glucose 3. muscle, liver & fat 4. pancreatic beta cells

1. efferent signal 2. initiating signal 3. effector 4. sensor/receptor

Three Types of Endocytosis

1. fluid endocytosis 2. phagocytosis 3. receptor mediated endocytosis

Factors that Alter Ion Channel Conformation

1. membrane potential (voltage) 2. ligands 3. membrane stretch

Positive Feedback in Parturition (Birth)

1. uterine muscles contract pushing baby's head against the cervix during labor 2. nerves from cervix signal brain to release oxytocin 3. oxytocin further stimulates uterine contractions

Transcellular Transport as Glucose in Small Intestine

1. when lumen glucose levels > epithelial cells, glucose can pass through apical membrane through glucose transporters via *facilitated diffusion* and exit through the basolateral membrane into the blood side 2. when lumen glucose levels are < epithelial cells, glucose enters into epithelial cell through apical membrane's *Na+/glucose symporters (secondary active transporters)* using the driving force of Na_ that is maintained by *Na-K-ATPase*; glucose then exits through basolateral membrane's glucose transporters via *facilitated diffusion* into blood side

Components of Blood

50 % plasma (hormones, ions, chemicals, etc.), 45% RBC, WBC, platelets

A muscle that is stretched until the thin filaments no longer overlap: A. will have high passive tension B. will fatigue quickly when stimulated C. will be able to lift a heavier load D. will use more ATP when it is electrically stimulated than a muscle at a normal length

A

A. Molecule B is ions fluxing an open ion channel B. Molecule A is glucose undergoing facilitated diffusion C. Molecule C is oxygen or CO2 diffusing through lipid membrane D. All of the above statements could be true

A

Consider the following scenario: Joe, a 25 year-old XY (male) swimmer from Chicago, Illinois (579 ft) is scheduled to compete at the upcoming championship game at Denver, CO (5289 ft elevation). on December. According to Joe's coach, Joe needs to train at Denver for the next 3-4 months to have his body ready to compete at this high altitude, at which the oxygen partial pressure is much lower. Which of the following may represent Joe's hematocrit at the end of the training period (December)? A. 47% B. 45% C. 42% D. 47% in the morning and 42% at night

A

Digitalis is a drug that inhibits the Na-K-ATPase pump in the cardiac muscle cells. Digitalis likely_________ Na+ ion concentration inside cardiac muscle cells. The change in Na+ ion concentration likely ___________ the 2nd active transport of glucose against its concentration gradient through the Na-glucose symporter. a. increases, decreases b. no option is correct c. decreases, increases d. increases, increases e. decreases, decreases

A

In diagram showing the relationship between power and velocity, the muscle is generating the greatest amount of force at: A. A B. B C. C D. D

A

Multiple sclerosis is a disease that results in the destruction of oligodendrocytes. Which of the following will be impaired in multiple sclerosis? A. velocity of axonal conduction B. AP inhibition C. resting membrane potential D. graded potentials initiated by synaptic transmission

A

Potocytosis is a form of endocytosis that occurs in tiny vesicles called caveolae. Caveolae are formed by caveolin proteins making a protein-coated pit at the cell surface membrane. They mediate the selective uptake of certain vitamins and other low molecular weight molecules. Which type of endocytosis listed below is this most similar to? a. Receptor-mediated endocytosis b. Phagocytosis c. Retrocytosis d. Fluid endocytosis (pinocytosis)

A

Relative to other fiber types, fast glycolytic muscle fibers have: A. small volumes of mitochondria B. large numbers of surrounding capillaries D. large amounts of myoglobin D. low myosin ATPase

A

Sherpa are an ethnic group who live at very high altitude in the Himalaya mountains. Their leg muscles contain fibers which have unusually small cross-sections. They may find this helpful because: A. small cross section reduces the diffusion distance for oxygen B. small muscle fibers produce more force than large muscle fibers C. small muscle fibers shorten more quickly than large fibers D. small muscle fibers contain lower proportion of myoglobin than fast glycolytic fibers

A

The process of long-term potentiation (LTP) seems to be important for the formation of memories LTP involves which of the following steps? A. Long lasting increase in neuronal sensitivity to neurotransmitters B. long lasting repression of neurotransmitter release C. long lasting decrease in synaptic contacts between neurons D. long lasting decrease in number of postsynaptic receptors

A

Which of the following signaling pathways best describes the mechanism of action for an steroid intracellular messenger? a. Retinoic acid (RA) diffuses into the cell and binds to an unbound receptor in the cytosol. The RA bound receptor complex then moves to the nucleus. Two RA bound receptor complexes come together to alter gene transcription activity. b. Prolactin enters the cell and binds to a cell membrane receptor. The binding causes a conformational change and the membrane receptor recruits and activates Janus kinase (JAKs). The JAKs phosphorylate several transcription factors to increase the synthesis of several new proteins. c. Estrogen diffuses into the cell and binds to a ligand-gated Ca2+ channel. The binding causes a conformational change that opens the channel. The Ca2+ diffuses into the cell and they bind to and activate calmodulin. Activated calmodulin increases the activity of several different kinases. d. A first messenger binds to a Gq G-protein coupled receptor. This activates phospholipase C (PLC) to breakdown a specific phospholipid in the membrane, which eventually leads to the activation of protein kinase C and Ca2+ release from the endoplasmic reticulum

A

Which of the following 1L solutions has the HIGHEST water concentration? a. 50 mM Glucose, 150 mM NaCl, 10 mM CaCl2 b. 50 mM Glucose, 150 mM KCl, 10 mM CaCl2 c. 40 mM Sucrose, 50 mM NaCl, 100 KCl, 10 mM CaCl2 d. 130 mM Glucose, 50 mM KCl, 50 mM CaCl2 e. 300 mM Glucose, 25 mM NaCl, 10 mM CaCl2

A a. 50(1) + 150(2) + 10(3) = 380 b. 50(1) + 150 (2) + 10(3) = 380 c. 40 (1) + 50(2) + 100(2) + 10 (3) = 370 d. 130(1) + 50(2) + 50(3) = 380 e. 300(1) + 25(2) + 10(3) = 380

(1) > 45% (2) <45% (3) = 45% A. In a person suffering from dehydration, hematocrit would be: B. In a person living at high altitude, hematocrit would be: C. In a person who abuses blood doping, hematocrit would be:

A. (1) > 45% B. (1) > 45% C. (1) > 45%

A

AThe figure below highlights the transcellular pathway of glucose from the lumen side to the blood side across an epithelial cell. The bottom figure shows the differences in the lumen, intracellular, and extracellular concentration of glucose. In the panel the numbers 1 and 2 label the _______________ and _____________ membranes, respectively. a. Apical, basolateral b. Cannot be determined based on the image c. Basolateral, apical

At this moment of the test, your adrenal medulla secrets a lot of epinephrine into your blood stream. In response, your heart beats a lot faster and harder. In this scenario, epinephrine elicits its effects on the heart rate via A. autocrine control B. endocrine control C. paracrine control D. direct neural control E. exocrine control

B

Dwayne passed out after running sprints on an extremely hot day. A quick assessment by the track coach showed his body temperature rose from 102F, 103F, to 105F. The coach and Dwane's teammates quickly submerged him in an ice water bath. His body temperature cooled to 97F but then increased to 98.6F. Which of the following statements is most likely TRUE? a. Dwayne's body temperature set point temporarily changed to 105F to help him sprint faster b. Dwayne's rising body temperature is likely an example of positive feedback c. Dwayne's body temperature would have eventually cooled to 98.6F without the ice bath d. Dwayne's lacks the normal homeostatic set point in body temperature

B

If we measure the electrical activity of a sensory nerve immediately before it enters the spinal cord, how can we estimate the intensity of the sensory input it carries? A. AP amplitude is proportional to stimulus intensity B. AP frequency is proportional to stimulus intensity C. AP amplitude and frequency are proportional to stimulus intensity D. we can't guess the stimulus intensity just based on nerve activity

B

Orexin stimulates the craving for food, making it a potential target for weight loss drugs. Based on the figure above, which of the following is a potential unintended effect of an orexin blocking drug? A. increased appetite B. increased sleepiness C. anxiety and insomnia D. intense tremors

B

The chemical sensation of taste depends on: A. only direct activation of ligand-gated ion channels in the sensory cells B. specialized receptor cells which do not have APs C. second messenger system activation of taste neurons D. receptive proteins on the free nerve endings

B

The figure shows a container with an impermeable membrane (dashed line) separating the left compartment and the right compartment. What direction would the membrane move if aqueous channels were place din the membrane? What direction would the membrane move if both aquaporin channels and carrier proteins for the solute were put in the membrane? A. left, neither B. right, neither C, left, left D. left, right E. neither, right

B

Which of the following statements is FALSE? a. The intracellular K+ ion concentration is greater than the intracellular Na+ ion concentration b. The directional movement of ions through ion channels is determined solely by their chemical (concentration) gradients c. Secondary active transport relies on the ionic concentration gradients established by primary active transport d. The binding and hydrolysis of ATP both cause conformational changes in the Na-K-ATPase pump

B also determined by membrane potential

Which of the following second messengers is NOT generated from the activation of a phospholipase? a. None is correct b. Phosphatidylinositolbisphosphate (PIP2) c. Arachidonic acid d. Inositol trisphosphate (IP3)

B generated by breakdown of plasma membrane

The twitch force generated by a single muscle fiber back to zero 40 ms after it is stimulated. Which stimulus rate (in cycles per second) will produce an unfused tetanus? A. 0.5 B. 5 C. 50 D. 500

C

After blood donation, plasma levels return within normal levels within a couple of dates. RBC take approx. 2 weeks to return to their normal levels. If an XY subject donates blood, his hematocrit will be __ 45% immediately after blood donation. __ 45% 5 days after blood donation. ___45% 8 weeks after blood donation. A. less than, greater than, equal to B. greater than, equal to, less than C. greater than, equal to, equal to D. less than, less than, equal to E. equal to, less than, equal to

C

Dr. Chemist has developed a hydrophilic non-ionizing, non-dissociable fluorescent dye X. In a separate experiment, Dr. Chemist has concluded that the compound X does not diffuse into the human cell. If a human RBC is placed in a solution consisting of 50 mM NaCl, 50 mM CaCl2, and 100 mM fluorescent dye X, what would you observe? A. the cell will stay the same B. the cell will shrink first then swell C. the cell will shrink D. the cell will burst

C

Normally, an "omni" cell undergoes mitosis in response to a "poke" hormone that binds and activates G protein coupled receptors. Imagine that a scientist has made a derivative "less omni" cell from the parent "omni" cell by inducing loss of function mutations in adenylyl cyclase so that this "less omni" cell does not have functioning adenylyl cyclase. Which of the following scenarios would describe the behavior of this "less omni" cell in response to a "poke" hormone? A. it will begin mitosis at a very high dose of the "poke" hormone B. it will first undergo mitosis but stop at the 2 cell stage, with a normal dose of the "poke" hormone C. it will not undergo mitosis even at a very high dose of the "poke" hormone D. it will undergo mitosis forever with a normal dose of the "poke" hormone

C

Oxytocin is a peptide hormone that causes an increase in intracellular cAMP in its target cells. Oxytocin stimulates the smooth muscle of the uterus to contract, but has no effect on smooth muscle cells of the small intestine. This difference in responsiveness exists probably because: a. oxytocin is not delivered to the smooth muscle cells of the intestine b. intestinal smooth muscle cells do not contain the second messenger system c. uterine, but not intestinal smooth muscle cells contain specific receptors for oxytocin

C

Sandra continuously recorded her body temperature for 30 days. She found that her body temperature fluctuated between 37.5C during the day and 36.9C at night. Which of the following is most likely TRUE? a. Warmer daytime temperatures slightly increase Sandra's body temperature during the day b. Sandra's body temperature slightly drops at night because sleep blunts neuronal reflexes c. The set point of Sandra's body temperature changes during the day and night d. Sandra might have an infection because she suffers a slight fever during the day

C

The CSF is produced by the choroid plexus and circulates between the brain ventricles and the subarachnoid space in the CNS. Which of the following is a characteristic of CSF? A. Na+ concentration is lower in CSF than in plasma B. K+ concentration is higher in CSF than in plasma C. protein concentration is lower in CSF than in plasma D. CSF has the same composition as plasma

C

The graph above shows the AP from a neuron that expresses both nicotinic receptors and GABA receptors, and receives input from a cholinergic neuron. Which of the following would be TRUE if the input were to be from a GABAergic neuron instead? A. AP would look the same B. value for point 1 would decrease C. curve of point 2 would go down instead of up D. amplitude of point 3 would be less

C

The structure that maintains the thin filaments in a hexagonal array when viewed in a cross section of sacromere shown right is: A. Actin (thin) B. M line C. Z line D. Myosin (thick)

C

Which of the following is most likely the cause of a depolarizing graded potential? A. opening of voltage gated sodium channels B. opening of voltage gated potassium channels C. activation of nicotinic receptors D. activation of GABA receptors

C

Which of the following situations best represents homeostatic mechanism? A. during a hot summer day, the core body temperature of a person increases as well B. before entering a room for an interview, a person is nervous and sweats a lot C. after eating a large batch of salty popcorn, the salt concentration in the urine increases D. eating a large size of fast food daily leads to an increased body weight E. as age increases, the skin loses its elasticity and becomes wrinkled

C

You are visiting your dear old uncle Bill and his family. Bill is close to 80 years old but he remains quite active, he rides his bike 3 miles to the public library and back every single day. As you chat with your cousins, they tell you that Bill often forgets their names. Bill's problem stems from impairment of: A. somatosensory cortex B. procedural memory C. faulty declarative memory D. all types of memory

C

Your friend can run a marathon (26 miles) in 2.5 hours (a very fast time for the event). Their leg muscles are likely to contain: A. exceptionally low amounts of sarcoplasmic reticulum B. very few capillaries C. high proportions of fast-oxidative glycolytic fibers D. unusually low concentrations of dystrophin

C

An important aspect of sensory physiology is the ability to discriminate between separate stimuli, for example, being able to identify whether we are being poked by one of two fingers. What are the mechanisms that allow us to do this? A. alterations in threshold stimuli B. spinal summation C. lateral inhibition D. large receptor fields

C.

A liver cell responds to the presence of the hormone epinephrine by increasing systolic cyclic AMP production, which leads to the catabolism of glycogen and also gluconeogenesis (conversion of glycerol, lactic acid, and amino acid to glucose). The best explanation for this phenomenon is: a. epinephrine binds to two types of receptors in plasma membrane b. activated receptor complex stimulates production of two different second messengers c. cyclic AMP can directly activate two kinds of enzymes d. cyclic AMP dependent protein kinase can activate two kinds of enzymes e. all of the above

D

A person suddenly starts with uncontrolled, jerky movements of the body. In the ER they must sedate the patient in order to do an MRI scan of her brain which showed that the patient has had a stroke. Where do you think this stroke is located? A. primary motor cortex B. somatosensory cortex C. brainstem D. basal ganglia

D

Activation of a receptor by a chemical messenger: a. occurs when the messenger binds to the ligand binding site of the receptor b. is the first step leading to the ultimate response of a cell to the messenger c. leads to a change in receptor conformation d. all of the above e. none of the above

D

Activation of which receptor type can increase ion channel signaling? a. Janus kinase-associated receptors b. None is correct c. Intracellular steroid receptor d. G protein-coupled receptor e. Receptor tyrosine kinases

D

During the progression to kidney failure, a person experiences an altered potassium balance in the ECF. As potassium concentration outside the cell increases above normal with no change in intracellular potassium concentration, which of the following is correct statement about neurons in this person's brain? A. the ability to fire an AP would be unaffected B. the amplitude of graded potential would be increased C. a greater stimulus required to fire an AP D. a smaller stimulus is required to fire an AP

D

Emily is a senior living at a dormitory without air conditioning. On a hot summer day, Emily finds herself feeling hot and sweating profusely. Yet, when she checks her temperature with a thermometer, it shows 98.5F which is normal in a healthy individual. Which of the following represents an efferent pathway in this scenario? A. temperature sensitive sensory neuron B. spinal cord C. hypothalamus D. motor neuron E. sweat gland

D

Epinephrine directly activates the cyclic AMP pathway in liver cells. Therefore epinephrine probably binds a specific. a. intracellular receptor in these cells b. tyrosine kinase receptors c. JAK-kinase associated receptors d. G protein coupled receptors

D

In cross section of a sarcomere, myosin molecules are found in: A. Actin (thin) B. M line C. Z line D. Myosin (thick)

D

Na+/glucose symporters consistently pump glucose from the lumen (1nM glucose) into the epithelial cell of the gut (5mM glucose). However, the glucose uptake via the Na+/glucose symporter is blocked by ouabain-mediated inhibition of the Na+/K+ pump. Based on this observation, you would conclude that the active transport of glucose by the Na+/glucose symporter is possible because the Na+/K+ pump maintains the LOW intracellular concentration of: A. ATPase B. glucose C. K+ D. Na+ E. positively charged proteins

D

Rapid Eye Movement (REM) sleep is also called 'paradoxical sleep'. Which of the following is characteristic of REM sleep? A. sleep walking typically occurs during this phase of sleep B. there are rapid movements called hyping jerks C. brain O2 consumption is lower than during nonREM sleep D. EEG activity is similar to that seen during wakefulness

D

Thapsigargin is a drug that inhibits sacro/endoplasmic reticulum Ca2+ ATPase. Treating skeletal muscle cells with this drug will: A. decrease the number of thick filaments B. reduce cytosolic Ca2+ concentration C. make it difficulty to create fused titanic contractions D. slow twitch relaxation

D

The cerebellum: A. initiates voluntary movements B. plays a role in most monosynaptic reflexes C. participates in the knee jerk reflex D. participates in the planning of movements

D

The sodium calcium cotransporter/exchanger is a membrane pump that works by a secondary active transport mechanism. It relies on the electrochemical gradient of sodium to pump calcium ions against its concentration gradient. Which one of the following statements about the sodium-calcium-exchanger is TRUE? A. the sodium-calcium-cotransporter directly converts ATP to ADP B. Flux through the sodium-calcium cotransporter does not saturate C. the sodium-calcium cotransporter is a symporter D. the sodium-calcium cotransporter pumps calcium ions out of the cell

D

Which molecules quickly diffuse through the lipid core of the phospholipid bilayer? a. All are correct b. Sucrose and glucose c. Water molecules and ATP d. Oxygen and CO2

D

Which of the following are common means by which binding of an intercellular chemical messenger with a cell's receptor brings about an intracellular response? a. opening or closing of specific ionic channels in the plasma membrane b. activation of an intracellular second messenger system c. promoting or inhibiting the transcription of genes that code for the synthesis of cellular proteins d. all of the above e. none of the above

D

Which of the following characteristics is TRUE in the ganglia of BOTH the parasympathetic nervous system and the sympathetic nervous system? A. preganglionic neurons release norepinephrine B. postganglionic neurons release acetylcholine C. postganglionic axons are longer the preganglionic axons D. nicotinic receptors are present on the postsynaptic membrane

D

Which of the following statements about the facilitated diffusion of glucose into cells is TRUE? a. The co-transport of Na ions down their electrochemical gradient is needed to transport glucose into the cell b. All options are correct c. The glucose concentration is lower outside the cell compared to inside the cell d. Facilitated diffusion of glucose requires ATP hydrolysis e. The movement of glucose inside the cell saturates at high extracellular concentrations

E a. glucose can also be transported via facilitated diffusion c. glucose concentration can vary outside and inside the cell d. facilitated diffusion is passive, does not require ATP

Endocytosis vs. Exocytosis

Endo: movement of molecule *Into* the cell via vesicles Exo: movement of molecule *out* of the cell via vesicles

Homeostasis as a Dynamic Process

Equilibrium: over time, no differences in compartementalization of X - no input of energy is required to maintain Homeostasis: over time, difference in orders are maintained between compartments

True or False: All steroid hormones must bind transmembrane receptor proteins in target cells in order to modulate target cell activities

False dont bind on membrane, bind in nucleus or cytosol

True or False: Most of the water in the human body is found int he plasma compartment

False most of the water in body is found in ICF

True or False: the positive feedback is homeostatic

False negative feedback is homeostatic

True or False: the set point for a physiological parameter cannot be changed

False set points can be reset via circadian rhythms, infections, etc.

Hypertonic vs. Hypotonic vs. Isotonic Solutions

Hypertonic: cell shrinks, ECF solute mOsm > ICF solute mOsm Hypotonic: cell swells, ECF solute mOsm < ICF solute mOsm Isotonic: no change in cell volume, ECF solute mOsm = ICF solute mOsm

A & B = one way flux C = net flux

Label the following

____________ block cyclooxyegenase which causes ________

NSAIDs reduce pain, fever, and inflammation

Symporters vs. Anti-porters

S: move molecules in *Same* direction A: move molecules in *opposite* directions both involved in secondary active transport

B

The figure below highlights the transcellular pathway of glucose from the lumen side to the blood side across an epithelial cell. The bottom figure shows the differences in the lumen, intracellular, and extracellular concentration of glucose. Based on the concentration differences of glucose (bottom panel), the membrane transport mechanism(s) for glucose transport through the transcellular pathway at (3) occurs by _________ and at (4) occurs by _________, respectively a. active transport, diffusion b. active transport, facilitated diffusion c. facilitated diffusion, diffusion d. diffusion, facilitated diffusion

True or False: Activation of membrane receptors can evoke rapid responses at the level of the plasma membrane and cytoplasm as well as slow responses involving transcription

True

True or False: fever is an example of resetting a set point

True

True or False: homeostasis requires energy

True

True or False: the plasma is a kind of extracellular fluid

True

True or False: the sensor in the reflex arc is the receptor

True

Most of the water in the human body is inside the cells? True or False?

True 2/3 water in body is inside cells

True or False: Hematocrit will go up during dehydration

True losing water causes liquid portion of blood to decrease, increasing percentage of RBS to total volume

C for specificity A for affinity

Using the binding curves for three different receptors (A, B,C) of the same chemical ligand shown below: Rank the receptor specificity for the chemical messenger & Rank the receptor affinity for the chemical messenger: a. A > C = B b. A = C = B c. A > C > B d. Cannot be determined based on the graph e. A = C > B

Reflex

a specific involuntary, unlearned "built in" response to a particular stimulus employs a neural pathway that involves a receptor (sensor) -- afferent pathway -- an integrating center -- efferent pathway -- effector

Phospholipase A2

activates Arachidonic acid (eicosanoids) pathways which include cyclooxygenase pathway and lipooxygenase pathway *key signaling event in inflammatory response*

The stretch of a ligand receptor interaction is referred to as _______________

affinity (high vs. low affinity binding sites) *different receptors might bind to same ligand with same specificity but different affinities or some might bind to same receptor with different affinities*

Tissues

aggregate of single type of specialized cells (i.e. muscle tissues, nervous tissues, epithelial tissues, connective tissues) can also denote general cellular fabric of any organ with multiple cell types

Flux

amount of material crossing the surface in a unit of time and depends on number of molecules

Types of Transmembrane Receptors

ion channels, G-protein coupled receptors (GPCRs), receptors with kinase activity

Net diffusion of ions through channels depends on__________ and ______________

ion concentration membrane potential

______________ and _______________ molecules have low lipid bilayer permeability

ionized polar

Dynamic Consistency

levels of variable can change over short periods of time but remain relatively constant over long periods of time

GPCR (Gs) Examples of Cellular Responses

lipolysis in fat cells and glyconeolysis (breakdown of glycogen)/gluconeogenesis (glucose synthesis) in liver

Spatial resolution of sensory stimulation is best on the skin of the:

lips

Name an important way in which cells regulate their own activity

maintain differences in fluid composition across the cell membrane

Rate of Diffusion

measured by the rate the intracellular concentration approaches equilibrium