The plasma membraneis more permeable to K+ than to Na+ at the resting stateIn _______________ transport, energy is directly required to move a substance _______________ its concentration gradient.active; againstA single phospholipid in the plasma membranedoes not exhibit any of the above characteristicsThe plasma membranehas a hydrophobic region between two hydrophilic regionsThe greater the lipid solubility of a substance, the slower the substance can diffuse through the membrane's lipid bilayer down its concentration gradient. (True or False)FalseThe tonicity of a solution refers to the effect that the ____.solution has on cell volume when the solution surrounds the cellIf osmosis is occurring, then you know there is a net movement of water toward an area ofhigher solute concentrationTwo properties of particles influence whether they can permeate the plasma membrane without assistance: ____.size and the relative solubility of the particle in lipidWhich of the following is correct? Exocytosis decreases the surface area of the plasma membrane. Endocytosis can help remove cytoplasmic debris from inside the cell. Both of the these Neither of theseNeither of theseTwo ATP molecules could provide energy for a sodium-potassium pump to move ____ ions out of the cell for every ____ ions it moves into the cell.6 Na+; 3 K+Carrier-mediated transport systems display _______________ which determines the kind and amount of material that's transferred across the membrane. specificity competition saturation all of the aboveall of the aboveThe term membrane potential refers to a separation of opposite charges across the membrane. (True or False)TrueThe voltage-gated sodium channel has two gates: an activation gate and an inactivation gate (True or False)TrueBinding of an excitatory neurotransmitter to a postsynaptic neuron causeschemically-gated Na+ channels openThe nervous system is specialized to control activities that require duration rather than speed. (True or False)FalseThe strength of a membrane stimulus coded by the _______________.frequency of action potentialsTo what ions do inhibitory synapses become more permeable?potassium or chlorideA threshold potential in a typical nerve cell isthe point at which there is an explosive increase in Na+ permeabilityThe stronger the triggering event, the larger the resultant graded potential. (True or False)TrueOn what three structures can a neuron terminate?muscle, gland, or other neuronNeurotransmitter is released by exocytosis into the synaptic cleft. (True or False)TrueThe output in a positive feedback system becomes ____.amplifiedWhich sequence represents a correct hierarchy of biological organization in a human, from smaller to larger?cell, tissue, organ, system, organismHomeostasis involves both short-term and long-term compensatory responses via intrinsic and extrinsic controls. (True or False)TrueThe extracellular fluid is made up of which two components?plasma and interstitial fluidWhat kind of glands secrete through ducts to the outside of the body (or cavity open to the outside)?exocrineEach spinal nerve carries afferent sensory fibers from a particular region on the body surface called a(n):dermatomeThe sympathetic and parasympathetic divisions are part of theautonomic nervous systemWhat area of the brain is associated with language comprehension?Wernicke's areaBroca's area is associated with _______________ language _______________.verbal, formation_______________ line the internal, fluid filled cavities of the central nervous system.Ependymal cellsWhich of the following is not a function of astrocytes? Hold neurons together in proper spatial relationship. Line internal cavities of the brain and spinal cord. Take up excess K+ to help maintain proper brain extracellular fluid ion concentration. all of the above are functions of astrocytesLine internal cavities of the brain and spinal cord.The conversion of stimuli into neuron potentials requires an adequate level of stimulus is called sensory transduction stems from generation of receptor potentials all of the aboveall of the aboveThe conversion of stimulus energy into a receptor potential is known as sensory transduction. (True or False)TrueWhat is the photopigment in rods?rhodopsinReceptorscan initiate action potentials in afferent neuronsIdentify the true statement(s) about sensory receptors: The larger the receptor potential, the greater the frequency of action potentials initiated in the afferent neuron. Tonic receptors often exhibit an "off-response." Phasic receptors are important in situations where maintained information about a stimulus is valuable. Receptors are part of efferent neurons.The larger the receptor potential, the greater the frequency of action potentials initiated in the afferent neuron.Photoreceptors are ____________________ by their adequate stimulus and ____________________ in the absence of stimulation.inhibited; excitedAs light passes from one medium to a medium of a different density, it is refracted bends at specific angles changes wavelengths two of the above are truetwo of the above are trueConvex surfaces converge light rays, bringing them closer together. (True or False)True____________________ is the process of converting light stimuli into electrical signals.PhototransductionEach autonomic nerve pathway (from the CNS to an innervated organ) consist of how many nerves?twoWhat neurotransmitter is released from the sympathetic preganglionic fiber?acetylcholineThe motor end-plate region undergoes a threshold potential, so an action potential is initiated at this site.FalseAcetylcholinesterase is located ____.on the motor end-plate membraneMotor-neuron axon terminals release ____________________, which brings about excitation and contraction of the innervated muscle cells.acetylcholineCalcium turns on cross bridges by physically repositioning the troponin-tropomyosin complex to uncover the actin cross-bridge binding sites inskeletal muscle and cardiac muscleA skeletal muscle fiber contains numerous ____________________, which are cylindrical intracellular structures.myofibrilsActin has ATPase activity are spherical forms a helical chain that forms the main structural component of the thin filaments two of the above are truetwo of the above are trueTemporal summation results primarily from a sustained elevation in cytosolic Ca2+. (True or False)TrueOne motor neuron, plus all the muscle fibers it innervates, is known as a(n):motor unitThe lateral sacs of the sarcoplasmic reticulum store ____________________.calcium ionsWhat types of muscles are involuntary in terms of movement?cardiac and smoothThe heart chamber that has the greatest work load isThe heart chamber that has the greatest work load isWhen the body is at rest, one complete cardiac cycle lasts eight seconds. (True or False)FalseAn autorhythmic cell membrane's slow drift to threshold is called the __________ potential.pacemakerParasympathetic stimulation and epinephrine enhance the heart's contractility. (True or False)FalseWhich of the following EKG waves represents ventricular repolarization? P wave QRS complex T wave Ventricular repolarization occurs simultaneously with atrial depolarization and consequently cannot be recorded.T waveThe aortic valve openswhen ventricular pressure exceeds aortic pressureWhat is the main determinant of cardiac muscle fiber length?the degree of diastolic fillingThe main effect of parasympathetic stimulation on the SA node is to speed up depolarization so that contraction is reached more rapidly. (True or False)FalseAn increase in parasympathetic activity ____________________ the stroke volume.has no effect onCardiac outputis the volume of blood pumped by each ventricle per minuteWhich valve(s) prevent(s) regurgitation (backflow) of blood from a ventricle to an atrium?Tricuspid and mitralWhich of the following is not associated with an increase in stroke volume?increased end-systolic volumeIn what fashion does healthy blood flow?laminarDuring isovolumetric phases of the cardiac cycle,all heart valves are closedDuring isovolumetric contraction,no blood enters or leaves the ventriclesWhat force drives arterial blood flow through the arteries during ventricular diastole?elastic recoil of the stretched arterial wallsThe flow rate of blood through a vessel is __________ proportional to the pressure gradient.directlyThe major site of sympathetic blood flow control (resistance changes) is at thearteriolesIn addition to the sympathetic nervous system, arteriolar radius is also extrinsically controlled by hormones (True or False)TrueSympathetic stimulation of veins ____ venous pressure and drives ____ blood toward the heart.increases; moreWhen blood pressure becomes elevated above normal,parasympathetic stimulation of the heart increasesIn an arteriole, if the blood vessel radius is 2 units and is then vasoconstricted to 1 unit,resistance increases 16 timesWhen blood pressure becomes elevated above normal, a physiologic compensatory response isincreased parasympathetic stimulation of the heartIf the pulse pressure is 44 mm Hg and the diastolic pressure is 68 mm Hg, the systolic pressure is _______________ .112 mmHgWhich of the following properties does not pertain to arterioles?They are richly innervated by parasympathetic nerve fibers to control blood flow.The major determinant of resistance to blood flow is the:blood vessel radiusThe most important feature that enables RBCs to transport oxygen is the __________ they contain.hemoglobinFibrinogen is a key factor in blood clotting. (True or False)TrueWhat are erythrocytes?red blood cellsWhat enzyme dissolves blood clot as part of the healing process?plasminErythropoiesis is controlled by erythropoietin, which is manufactured in the:kidneysHemoglobin saturation decreasesas PCO2 increasesA person who has a tidal volume of 400 ml/breath, a respiratory rate of 14 breaths/minute, and an anatomic dead space volume of 120 ml will have an alveolar ventilation rate of3920 ml/minuteIf physiologic dead space remains constant, which condition would result in the lowest alveolar ventilation rate?a low respiratory rate and low tidal volumeThe lungs' elastic behavior results from elastin fibers and alveolar surface tension. (True or False)TrueWhen pulmonary compliance is __________, such as with pulmonary fibrosis, more work is required to expand the lungs.decreasedBronchodilation of the air passages involves the _______________ of their smooth muscle and the _______________ of their radius.relaxation; increaseThe partial pressure of oxygenin blood is the most important factor that determines percent O2 saturation of hemoglobinWhich of the following does not bring about increased airway resistance?epinephrineIdentify the factor(s) that would increase hemoglobin's affinity for oxygen in a red blood cell. Lowering the concentration of carbon dioxide in the cell Increasing the concentration of H+ in the cell Reducing the pH in the cell Two of the above increase hemoglobin's affinity for oxygenLowering the concentration of carbon dioxide in the cellAny ventilated alveoli that do not participate in gas exchange with blood because they are inadequately perfused with blood are considered ______________ dead space.alveolarThe volume of blood given during a blood donation is approximately one pint (500 mL). If that volume of blood has 50 mL of gaseous oxygen in it, what volume of that oxygen would be physically dissolved in the plasma?0.75 mLThe abnormal condition of air in the pleural cavity is known as:PneumothoraxAltering the volume of the lungs can change alveolar pressure, in accordance with __________ law.Boyle'sApproximately what percent of carbon dioxide is transported in the blood in dissolved form?10%When the diaphragm contracts,the volume of the thoracic cavity increasesDuring inspiration, alveolar pressure is _______________ atmospheric pressure.less thanPulmonary surfactant is a complex mixture of lipids and proteins secreted by:type II alveolar cellsThe most important factor determining the percentage of hemoglobin saturation is the:PO2 of the bloodAbout 30% of the CO2 combines with hemoglobin to form carbamino hemoglobin (HbCO2). (True or False)TrueHow are glucose and amino acids reabsorbed in the proximal tubule?secondary active transportGlomerular filtrationis the process by which plasma water, electrolytes, and small molecules, which enter Bowman's capsule (space), are separated from blood cells and protein, which remain in the glomerular capillariesThe transport (tubular) maximum (Tm) is the maximum ratea substance can be reabsorbed because of saturation of the carrier moleculesTransport (tubular) maximum (Tm) is the maximum rate at which a substance is transported by a carrier protein across a tubular cell membrane is the maximum rate at which a substance is filtered by the glomerulus and moves into Bowman's space occurs when the membrane carriers becomes saturated two of the above are truetwo of the above are trueWhich of the following is(are) a direct stimulus(stimuli) for aldosterone release? angiotensin II decreased plasma potassium concentration decreased plasma sodium concentration two of the aboveangiotensin IIThe most prevalent ions secreted by the tubules are:hydrogen and potassiumMajor Glands of Endocrine SystemHypothalamus Pituitary Thyroid Adrenal Parathyroid GonadsTropic HormoneHormone that regulated production and secretion of another hormoneWhat are the hydrophilic hormonesPeptide and CatecholaminesWhat are the Lipophilic HormonesThyroid hormone and Steroid HormoneProcessing of peptide hormone1. preprohormones synthesized by rER and migrate to Golgi in membrane bound vesicles 2. while in ER and golgi, preprohormones are processed into prohormones followed by active hormones 3. golgi packages and labels hormones into secretory vesicles that are stored in cytoplasm until appropriate signal 4. upon signal, vesicle membrane fuses with plasma membrane and peptide hormone is exocytosedPrecursor for all steroid hormonesCholesterolPeptide hormones dissolve in blood (True or False)TrueSteroid/thyroid hormones dissolve in blood (True or False)FalseCatecholamine circulation50% circulate as free hormone 50% bound to albuminPeptide hormones and catecholamines bind with receptors on the target cells _____Outer plasma membrane surfaceSteroid and thyroid hormones bind to target cells' _____intracellular receptorsTwo ways hormone functions on target cell by altering the cell's protein:1. hydrophilic hormones activate second messenger pathways to alter the activity of preexisting intracellular proteins 2. lipophilic hormones directly activate gene expression in the target cell forming new proteinsPlasma concentration of free (active) hormones depends on1. rate of secretion into the blood 2. rate of metabolic activation/conversion 3. binding to plasma proteins (lipophilic hormones only) 4. rate of removal by inactivation and excretion in urineTwo components of pituitary glandposterior pituitary- neural tissue neurosecretory axons anterior pituitary- glandular tissue secretes hormones directly into bloodPosterior Pituitary HormonesVasopressin (antidiuretic hormone [ADH]) OxytocinVasopressin controlled byHypothalamic osmoreceptorsTwo most important factors that regulate anterior pituitary hormone secretion are1. hypothalamic releasing and inhibiting hormones 2. negative feedback by target-gland hormonesHypothalamic-hypophyseal portal system connects the ___hypothalamus and anterior pituitaryPortal System:capillary bed connected to another capillary bed via connecting vesselRegulation of secretion of anterior pituitary hormones controlled byhypophysiotropic hormones released from neurosecretory cells of hypothalamusTRH stimulatesTSHCRH stimulatesACTHGnRH stimulatesFSH and LHGHRH stimulatesGHGHIH inhibitsGH and TSHPRH stimulatesPRLPIH inhibitsPRLAnterior Pituitary HormonesTSH (tropic) ACTH (tropic) FSH (tropic) LH (tropic) GH (tropic and non) PRL (nontropic)3 hormone chain of commandHormone 1: hypophysiotropic (releasing/inhibiting) hormone (TRH, CRH, GnRH, GHRH, GHIH) Hormone 2: target-gland tropic hormone (TSH, ACTH, FSH/LH, GH) Hormone 3: target-gland hormone (thyroid hormone, cortisol, estrogen/testosterone, IGF-1)Fetal growth is stimulated byhormones from placentaAfter birth, _____ largely regulates growthgrowth hormoneFunction of growth hormone1. metabolic- binds directly to adipose tissue to breakdown triglycerides into fatty acids and use of liberated fatty acids as an energy source, conserves glucose for glucose-dependent tissues, & increased blood glucose by decreasing uptake by muscles 2. growthgrowth hormone stimulates liver production of ____insulin-like growth factor 1 (IGF-1)Hyperplasiaincreases number of cellsHypertrophyincreases size of cellsOsteoblastsproduce matrixOsteoclastsbreak down bony tissueEpiphyseal platedisc of cartilage between end and shaft of bone that grows to lengthen boneChondrocytescartilage cellsThyroid hormone and growth- required for synthesis of GH - growth severely stunted in hypothyroid children - hypersecretion does not cause excessive growthInsulin and growth- stimulates fetal growth - stimulates postnatal growth by stimulating secretion of IGF-1 - hyperinsulinism often spurs excessive growthTestosterone and growth- stimulates secretion of GH and IGF-1 at puberty - testicular testosterone responsible for heavier male musculature - stimulate closure of epiphyseal platesEstrogen and growth- stimulates secretion of GH and IGF-1 at puberty - stimulate closure of epiphyseal platesPeripheral Endocrine Glands:- thyroid gland - adrenal glands - endocrine pancreas - parathyroid glands - gonadsFunctional unit of thyroid is theFollicleParafollicular cells (C cells) produce _____calcitonin to reduce blood calciumThyroid hormone is derived from amino acidtyrosine (stored in colloid as a precursor: thyroglobulin)The two hormones that make up the thyroid hormone:T4 (thyroxine) prehormone T3 (triiodothyronine) true hormone (4x more potent)Effects of thyroid hormone- affects nearly every cell in body - main determinant of basal metabolic rate - increases target cell responsiveness to the catecholamines by increasing number of NE and Epi cell membrane receptors - Essential for normal growthincreased basal metabolic rate (BMR) leads to:- increased O2 consumption - increased energy and heat productionthe main regulator of TH secretionTSHTSH is released in response toTRH from hypothalamusTwo organs of adrenal gland1. adrenal cortex (outer portion, secretes steroid hormones) 2. adrenal medulla (inner portion, secretes catecholamines)Basic steroid hormones of adrenal cortex- mineralocorticoids (aldosterone) - glucocorticoids (cortisol) - sex hormones (DHEA)Aldosterone secretion is increased in response to two factors:1. activation of the renin-angiotensin-aldosterone pathway in response to a reduction in plasma (Na+) or a fall in blood pressure 2. direct stimulation of the adrenal cortex by rise in plasma (K+)Metabolic effects of cortisol- plays a major role in stress response - stimulates gluconeogenesis when liver glycogen stores become depleted during fasting - tissues use fatty acids, glycerol and amino acids to synthesize ATP - maintains normal blood glucose levels between mealsChromaffin cellsmodified postganglionic sympathetic neuronsAdrenal medulla releases the catecholamines:epinephrine (80%) and norepinephrine (20%)Epinephrine effects on organs- mobilize resources for physical exertion in emergencies (fight/flight) - increase HR and cardiac contraction (increased CO) - arterial vasoconstriction (increased TPR) - arterial vasodilation of coronary and skeletal muscle blood vessels - dilation of respiratory airwaysEpinephrine metabolic effects- makes stored carbs and fat available for use as energy - increases blood glucose by initiation glycogenolysis and gluconeogenesis in liver - promotes lipolysis to increase free fatty acids in bloodFuel Metabolismreactions involving degradation, synthesis and transformation of energy-rich organic moleculesAnabolismsynthesis of larger molecules from smaller molecules requires ATPCatabolismbreakdown of larger molecules into smaller moleculesTwo levels of catabolism breakdown1. hydrolysis - large cellular molecules -> smaller subunits 2. oxidation - smaller subunits -> ATPAbsorptive State- period after a meal when nutrients are absorbed and entering blood - glucose is plentiful and serves as the major energy sourcePostabsorptive state- period beginning after complete absorption of previous meal - stored fuel (fats/proteins) is used as energy sourceBlood concentration of nutrients does not fluctuate between absorptive and postabsorptive states (True or False)TrueIslets of Langerhans- pancreatic endocrine cells - beta cells: site of insulin synthesis and secretion (60% of islet cells) - alpha cells: site of glucagon synthesis and secretion (25% of islet cells)Insulin:- protein hormone secreted during absorptive state (stimulus is increased blood glucose) - promotes cellular uptake of glucose, fatty acids, and amino acids - enhances their conversion into glycogen, triglycerides, and proteins - lowers blood concentrations of these small organic molecules -> promotes storageInsulin lowers blood glucose four ways:1. facilitates glucose transport into most cells 2. stimulates glycogenesis 3. inhibits glycogenolysis 4. inhibits gluconeogenesisGlucagon:- protein hormone secreted during postabsorptive state - promotes cellular breakdown of glycogen, triglycerides, and protiens - inhibits glycogenesis - stimulates glycogenolysis - stimulates gluconeogenesis by liver - stimulates protein breakdown by liver - stimulates fat breakdownFive processes of digestion1. motility - muscular contractions to move and mix contents of GI tract 2. digestion - chemical breakdown of macromolecule polymers to monomers 3. secretion - digestive "juices" secreted into GI tract lumen 4. absorption - transfer of small molecules resulting from digestion into blood or lymph 5. elimination - excretion of waste as fecesTwo types of Motility1. propulsive movements : push contents forward through the digestive tract (peristalsis) 2. mixing movements (segmentation contractions)Mixing movements (segmentation contractions) serve two functions1. mixing food with digestive juices (enzymes, acids) promotes digestion 2. facilitate absorption of monomersWall of digestive tractMucosa: inner layer (modified for protection, secretion, and absorption) Smooth muscle: middle layer (circular and longitudinal layers) Serosa: outer layer (synthesizes slipper fluid to lubricate digestive organs)Digestive motility and secretion are regulated by:1. autonomous smooth muscle function (slow wave potentials) 2. intrinsic nerve plexuses (enteric nervous system, lies entirely within GI tract) 3. extrinsic nerves (autonomic NS, modifies actions of intrinsic nerves) 4. gastrointestinal hormonesSlow wave potentials- basic electrical rhythm of GI tract - spontaneous, rhythmic cycles of depolar and repolarizationInterstitial cells of Cajal- pacemaker cells for slow wave potentials - generate slow wave potentials that spread via gap junctions - similar to pacemaker potentials in cardiac muscleExtrinsic Nerves- nerve fibers from parasympathetic and sympathetic NS - regulate GI function by modifying intrinsic nerve plexuses - synapse directly on glands to regulate secretion - synapse directly on GI smooth muscleParasympathetic NS- increases smooth muscle motility - promotes secretion of digestive enzymes/hormonesSympathetic NS- inhibits continuous action potentials by interstitial cells of cajal - prevents uncoordinated activityMOUTHdigestion: - salivary amylase (hydrolyzes polysaccharides into disaccharides and monosaccharides) absorption: - no absorption of nutrients in mouthEsophageal stage of swallowingPrimary peristaltic wave sweeps bolus from beginning to end of esophagus Secondary peristaltic waves clear lodged bolus if not initially carried to stomachESOPHAGUSSecretion- mucus (protection) Digestion- none Absorption- none3 functions of stomach1. stores ingested food until emptying into small intestine 2. secretes HCl and digestive enzymes 3. squeezes, pushes, and grinds chymeStimulation of gastric motilityvolume of chyme in stomach increases gastric emptyingInhibition of gastric emptying1. fat 2. acid 3. hypertonicity 4. distensionGastric mucosa contain the following specialized cells- chief cells: produce pepsinogen - G cells: produce gastrin - ECL cells: produce histamine - Parietal cells: produce HCl - mucus cells: produce mucusFunctions of HCl-does not digest anything - denatures pepsinogen and provides optimal pH for pepsin function - aids in breakdown of connective tissue and muscle fibers (denatures proteins) - kills most microorganisms ingested with foodFunctions of pepsin- since pepsin digests proteins, must be stored in inactive form (activated by low pH) - digests certain peptide bonds resulting in protein fragmentsautocatalysispepsin activates pepsinStomach (digestion/absorption)digestion: - carbohydrate digestion continues within bolus of food via salivary amylase - protein digestion via pepsin absorption: - ethyl alcohol - aspirin3 phases of migrating motor complex (MMC)Phase 1: 40-60 minutes with few, weak contractions Phase 2: 20-30 minutes with some, moderate contractions Phase 3: 5-10 minutes with rapid intense contractions regulated by motilinPancreatic enzymespancreatic proteases: digest proteins pancreatic amylases: digests starches pancreatic lipases: digest fatFunctions of liver:- removes glucose from blood and stores as glycogen - processes fats and AAs - stores vitamins - detoxifies poisons and drugs - makes blood proteins digestive importance: synthesis/secretion of bileSmall intestine secretion and digestiondisaccharides and aminopeptidasesAbsorption in small intestine- absorbs almost everything presented to it (most occurs in duodenum and jejunum) - large surface area for diffusionDigestion and absorption of carbs- digestion begins in mouth, continues in duodenum and jejunum - Glu and Gal absorbed by secondary active transportGlucose absorption- absorbed by Na+ dependent secondary active transportDigestion and absorption of proteins- begins in stomach, continues in duodenum and jejunum - symporters move amino acids into intestinal cells against concentration gradient with Na+ (secondary active transport) - symporters move small protein fragments into intestinal cells against concentration gradient with H+ (tertiary active transport)Digestion and absorption of lipid- begins in duodenum - monoglycerides and fatty acids are passively absorbed at the brush border - bile salts absorbed in terminal ileum and move into lactealsDefecation reflex- distension of walls of rectum by feces stimulates stretch receptors in rectal wall - relaxation of external anal sphincter permits defecationLarge intestine: digestion and secretionDigestion: - none - harmless colonic bacteria digest some cellulose for their own use Secretion: - no digestive enzymes - alkaline mucus (facilitates passage of feces, neutralization of any local bacterial acids)Large intestine: absorption- less surface area than small intestine - no special transport mechanisms - absorbs mostly Na+ (actively), Cl- (passively), and H2O (osmotically)

BIO 270 LECTURE FINAL

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