BIOL 3470 Midterm Reviewer PDF

BIOL 3470 Changing environment responses (1) extinction or extirpation (2) physio adaptation via genetic change overtime (3) acclimatization and (4) behaviour response - easiest. milieu interior - internal conditions maintained while adjusting to environment and stress for optimal survival negative...

BIOL 3470 Changing environment responses (1) extinction or extirpation (2) physio adaptation via genetic change overtime (3) acclimatization and (4) behaviour response - easiest. milieu interior - internal conditions maintained while adjusting to environment and stress for optimal survival negative feedbacks≥≥… i.e. cold stressor > Tb drop > thermal receptor acknowledge > neuroendocrine response > physio response = shivering > return to normal Tb > negative feedback turned o Phenotypic plasticity - individual-level ability to exhibit more than one version of phenotype in response to changing environment , reversible or irreversible i.e. daphnia develop helmets and spines in response to predator-present environment i.e. perch reared at high CTmax Time frame of adaptive response Phenotypic acute - minutes to hours chronic - months acclimatization - reversible physio response to a complex suite of changing environment acclimation - reversible physio response to changing factor in lab Genotypic evolution - response to chronic changing environment over many generations i.e. chromosomal inversion in walleye (pickerel) - speciation in the North MB and Red River pop THERMAL BIOLOGY Poikilo - cannot regulate Tb and rely on uctuating Ta Homeo - constant Tb (narrow range) independent of Ta birds and mammals Ecto - can regulate Tb by relying on external source sh (salmon) Endo - can regulate Tb ( uctuating?) by generating heat from metabolism Poi kilo-like endo - can regulate Tb, but uctuates due to burrow system naked mole rat Steno- ecto- can regulate Tb by relying on external source, but Ta rarely change notothenioid sh Antarctic maintained cold Ta, loss of ability to sustain heat Hetero- can switch between regulatory strategies to maintain constant Tb Temporal hetero - seasonal Tb regulation hibernators Regional hetero - di erent Tb in some regions blue n tuna, reindeer (warmer core), opah (warmer cranium) 1 fl ff fl fl ff fi fi fi Zone of tolerance ZOT - range of Ta within which organism can maintain physio functions Lethal limits - Ta which 50% of organisms die causes are linked to ecology i.e. ice sh - loss thermal response small ZOT gastropod high ZOT Critical Thermal Max Trial (CTmax) - studies highest Ta which organisms remain vital Acclimation (in lab) can increase tolerance and CTmax i.e. Fish exposed to heat increase RMR (acclimation) levels o MMR (aerobic capacity) Aerobic scope (MMR-RMR) decreasing Population-speci c - High predictability during migration Ta has STRONG e ects in… physio processes Q10 = rate of change of physio process cause by a 10˚C change in Ta determines sensitivity of organism to changing Ta High Q10 - strong response Low Q10 - weak response Ectotherm Q10 promotes understanding towards its tolerance, while Endotherm Q10 allows understanding of its energy requirements to maintain Tb metabolic rate MR **positive correlation until critical threshold, when high Ta begins to denature protein and enzymes** Ectotherm Adaptive Response Resistance - expand ZOT to remain close to lethal limits for extended periods only activated is required, adaptation from pre-existing genes, can vary latitudinally Cold hardiness - ability of polar and alpine species to survive and thrive in the cold Problem: Organisms are 80% water and can freeze = Intercell uid ICF 2/3 + Extracell uid ECF 1/3 dehydration - freezing o sets osmotic gradient favouring water to move out of cell ICF freezing - cell death by mechanical damage from ice crystals Anhydrobiosis/Cryptobiosis - extensive dehydration within cells leading to dormancy i.e. tardigrades - accumulate sugar protectants to dehydrate Vitri cation - solidi cation of H2O in plants into amorphous non crystalline sugar glass, which cannot form ice crystals Freeze Avoidance increase [solutes] decrease freezing point **negative correlation** Thus, SW (more solutes) has lower freezing point (-1.9˚C) than FW (0˚C) Organisms isosmotic with SW have the same freezing point (-1.9˚C) Supercooling - ability of water solutions to cool below freezing point without freezing 2 fi fi ff fi fi ff ff fl fl  Thermal Hysteresis - T at which phase change (freezing) is di erent during warming compared to cooling Problem: Di cult maintenance of SCP glycerol - polyols sugar cryoprotectant, synthesized from glycogen using ATP soluble and non toxic stabilize membranes, inhibiting ice nucleator Reading: Two Insects-one plant Gall Moth Gall Fly Gall Type Elliptical Gall Ball gall Winter survival Freeze avoidance Freeze tolerance SCP Lowers SCP Raises SCP Accumulates cryoprotectants: Antifreeze Mech Produce glycerol and AFPs glycerol, sorbitol, proline 15˚C glycerol synthesis Trigger for cryoprotectant 5˚C glycerol synthesis 5˚C sorbitol synthesis Reduce body water, evacuate Water content No signi cant reduction gut contents No cocoon - slow extracellular Protection from ice Waterproof silk cocoon freezing to allow cell to adjust Sorbitol recovered to glycogen Cryoprotectant catabolism Glycerol is retained during winter mid-winter, glycerol used as fuel in spring Proline accumulates to help Membrane stabilization stabilize Antifreeze proteins AFPs - adsorb to ice crystal to inhibit expansion and lower freezing point Evolution: (1) mutated from sialic acid duplication (2) in notothenioid AFGP - mutated from trypsinogen - convergent evolution i.e. teleost - hyposmotic (lower solute in body than SW) - cannot a ord even partial freezing cannot produce cryoprotectants, use AFPs until -1.9˚C, ice crystal forms below that I.e. winter ounder - Antarctic stenotherm, increase AFPs during winter and decrease in summer Freeze tolerance Ice management - increase [cryoprotectants] in ICF to lower freezing point - maintain as liquid i.e. amphibians - dictate conditions of freezing to endure shorter periods of mild freezing redistribute cryoprotectants, glucose, from ECF to ICF conversion of liver glycogen to glucose is triggered by outer skin freezing 3 fi fl ffi ff ff  once glucose is exhausted, ECF SCP increases back plasma - ice nucleating protein slow speed and keep freezing size small i.e. ICF urea - triggered by fall hibernation, to prevent cell dehydration and stabilize mem evolved from hyperglycaemic response to dehydration (similar to freezing) Anoxia - complete absence of oxygen Ischemia - frozen heart and vessels suspend aerobic metabolism, and switch to anaerobic glycolysis (lactate). Lower ATP requirement i.e. wood frogs (acclimated pop in Alaska can survive longer in anoxic conditions than Ottawa pop) release brinogen upon freezing contributes to clotting to prevent tissue damage from freezing and thawing Metabolic compensation Acclimation prepares species for future stress by moderating MR i.e. Q10 acute > Q10 chronic Cold acclimated species acute stress from warm Ta steeper increase in MR chronic stress from warm Ta less steep, metabolic adjustment Cold acclimated MR > Warm acclimated MR when exposed to warm Ta Temperature polygons - MR returns to original level to stabilize i.e. reptile acclimated at 35˚C transfered to 10˚C (cold) acute stress steep decrease in MR held in for 4w chronic stress increase and stabilize MR (acclimated) transfered to 35˚C (warm) acute stress steep increase in MR held for 4 w chronic stress decrease and stabilize MR (acclimated) i.e. Poikilotherms - cannot regulate Tb, rely on Ta was able to evolve genotype overtime to maintain MR despite broader temperature range These 2 compensations involve from enzymatic reactions that are primarily in uenced by Ta isoform - enzymatic conformations for speci city to complement substrate Activation energy Ea - threshold to be reached to convert ES to EP Maxwell Boltzmann function MB - distribution of kinetic energy of molecules’ speed a at a given temp Regulation of enzymatic rates Increase [S] - increase probability of binding Increase [E] - increase catalytic site and reaction rate cold-acclimated in to warm Ta Lowering of Ea high MB function - increase molecule speed and collision = energy to reach Ea faster 4 fi fi fl  I.e. Ea polar < Ea tropical - better stabilizing enzymes to prevent conformation - allows them to su cient enzymatic rates to survive the cold Tb plays a critical role in determine bioenergetics ∆G rather than evolutionary history. Why can’t Ea’s be as low as possible? Ine cient enzyme activity - cannot keep up with enhancements of increase MR from increase Tb Too rapid enzyme activity - further increase MR for high Tb = overheating than can denature proteins, deplete energy, and cause oxidative stress High Tb -∆G: favour enzymatic reaction to proceed = overheating denature and lose functional shape (speci city) of proteins and enzymes +∆G: rigid enzymes does not lose functionality and speci city Low Tb +∆G: does not favour reaction - cannot reach Ea -∆G: lower Ea Allometry - fundamental impact of body size to all aspects of biology Body size limits impacts homeothermy Large spp tend to be more thermally resistant, fasting resistant (energy stores) and hypoxia tolerant (O2 stores) inertial homeotherms - store heat in long periods of time to thermoregulate Increase body size: increase MR Surface Law - SA:V rule Smaller spp have high SA:V high nutrient and gas exchange but also faster to lose heat Larger spp have low SA:V complex body systems and high O2 stores, but low nutrient and gas exchange Mass-Speci c MR - energy expenditure per mass Higher for small spp. Total MR Higher for large spp. * Endotherms have higher MR for thermoregulation high digestion, gestation, muscle contraction exploit colder niches sustained aerobic activity * Ectotherms have lower MR lower size limits easily go into torpor partitioning of energy for reproduction BMR - minimal MR for fasting, resting endotherm in thermoneutral Thermoneutral Zone - range of Ta where Tb is regulated by non- metabolic means with LCT and UCT Scholander-Irving model - BMR occurs at TMZ, Ta outside TMZ is where MR increase to thermoregulate 5 ffi fi ffi fi fi  Max MR - peak where MR begins to decrease due to biological limits Metabolic Slope: MMR-BMR Behavioural compensation - avoidance of areas outside ZOT Stable Tb Q (heat loss) = MR (heat production) In Endotherms C x (Tb - Ta) 1. Thermal conductance (C) rate of heat loss Acute - Thermal C/I in TNZ short-term decrease C = increase I (until LCT is reached) piloerection Curling up and huddling increase C = decrease I Spreading out Spreading saliva and urine on fur = evaporation Chronic - Thermal C/I long-term physio Increase fur thickness Genotypic - Thermal C/I evolutionary changes Down feathers Blubber Bergmann’s rule - larger spp. occur in polar, smaller spp. occur in tropics Allen’s rule - shorter appendages to reduce heat loss 2. MR adjustments Facultative thermogenesis Shivering - non synchronous contraction promote heat loss interfere with mobility when evading predators muscled far from core, doesn’t a ect much Non-shivering Brown adipose tissue BAT - high mitochondria, myoglobin and lipid levels, rich in SNS (unconscious control) - can turn on/o quick i.e. eutherian, neonates, and hibernators - position to directly heat vital organs UCP1 - alternate pathway for H+ to enter matrix no ATP, energy is used to generate heat GDP - blocks UCP1 and resume use of PMF for ATP Synthesis cold stimulus > CNS > SNS > release noreph > adrenergenic receptors > cleave fatty acids in BAT > fatty acids remove GDP > UCP1 activated acclimation can increase BAT and UCP1 3. Altering Tb-Ta gradient Vascular adaptation Vasoconstriction to impede blood ow to extremities Counter current heat exchange - retia/rete with intermingled bundles of anti-parallel vessels warm blood from core to tissues transfer heat to veins cold blood from veins to core receive heat 6 fl ff ff  4. Torpor/Fasting - reducing Tb and MR reversible imitated if Ta is below LCT hypothalamus set point > downregulate MR > Tb until Tb < Set Fasting endurance decrease with size - energy stores Small spp have high MR scope (variability) Large spp. have lower MSMR - cannot sustain torpor ** Small spp. have high MSMR and short fasting endurance ** compatible with torpor 5. Daily Heterothermy - vary MR over 24-hour period i.e. tiny mammals and birds lower MR to lower energy costs 6. Seasonal Endothermy true hibernators/ Deep torpor - rely on body stores and cache (2x mass in fall), dramatically lowers MR and costs seasonal lethargy - not true hibernation, inhibit metabolism allow cooling to 30˚C estivation - small reduction in Tb and MR - maybe resource shortage Evolved from pedomorphic trait - adaptive bene ts of torpor retained in adulthood Neonatal hibernators - reduce MR and Tb, BAT, diminish cardiac SNS to prevent cardiac arrest Also, evidence on torpor as ancestral trait from mammals: monotremes, marsupials and eutheria Regional endothermy - by active continuous sh species Heater organs i.e. enlarge rectus eye in tuna - rete and adipose tissue packed with mitochondria lack Ca2+ binding = unable to contract, cannot shiver Red muscles/ slow twitch - has lots of mitochondria and myoglobin for constant movement use O2 to generate heat and ATP Rete/Retia - conserve heat via CC heat exchange Excitation thermogenic coupling SNS sends axon motor stimulates Ca2+ release from SR via Ca2+ ATPase consume ATP for Ca2+ to return to SR channel is modi ed to slow close some Ca2+ enter mitochondria Na+ enter mitochondria for Ca2+ to exit H+ enter active transport mitochondria for Na+ to exit H+ used in ETC and ATP Synthase ETC generate heat Aerobic respiration generate ATP energy using proton movement across gradient (PMF) utilize O2 and energy from ETC and fuel oxidation, which also produce other forms of energy (i.e. heat) 7 fi fi fi  NEUROENDOCRINE To coordinate cellular and physiological response to external and internal stimuli, to biotic and abiotic variables Nervous system sends electrical signal via neurons at the end of each neuron, released as neurotransmitter to ‘ re’ reach target cell - speci c cellular receptors rapid response (secs - mins) Endocrine system sends chemical signal or hormones via blood circulation reach target cell - speci c cellular receptors continuous until hormone levels decrease - slow (hours-days) Short Distance direct cell - adjacent cells communicate thru gap junctions Autocrine - release signalling molecules act on receptors on its own surface Paracrine - release signalling molecules that a ect nearby cells in a localized area Long Distance - enter the blood stream Endocrine - hormones secrete to the bloodstream travel to distant target cells Neural - neuron releases hormone (neuropeptides) via synaptic junctions and target distant cells Location exteroreceptors - respond to external stimuli interoreceptors - respond to internal stimuli Transduction to become electric/chemical signal Ionotropic - interact with Na+ channels Metabotropic - interact with cascading receptors, then eventually interacts with Na+ channels **high density and type of sensory receptors in tissue signify its importance for survival 1. Sensory Systems - detect environmental variables receptor cells - transform stimuli to electrical or chemical signal sense organs - group of receptor cells (i.e. eyes, nose, tongue) Forms of stimuli electromagnetic - photo- electro- magneto- iono i.e. Sharks water vibrations > pores > canal of lorenzini > neuromasts > iono > sensory I.e. Eagles Fovea (better resolution) > photoreceptor > visual i.e. Trout photoreceptor > larger optic lobe mechano - auditory, mechano-, vestibular (inner ear, balance) iono i.e. Paci c Salmon water vibrations > gel > hair cell in lateral line > iono > electrical > evade predator chemical - olfactory, taste metabo 8 fi fi fi ff fi  i.e. cat sh chemical response > barbels > metabo > nd prey i.e. star nosed mole mouth > chemoreceptor > nd prey 2. Nervous System - produce electrical signal and rapid response CNS - brain and spinal cord PNS somatic - muscle movement autonomic - unconscious control sympathetic - catecholamines, noreph, and eph ‘ ght or ight’ parasympathetic - acetylcholine ‘rest and digest’ enteric - gut tract sensory receptors - a erent - towards CNS away from CNS - e erent - skeletal muscles Parts of a Neuron dendrite - receive chemical signal from pre-synaptic soma - generate action potential from signal axon - conduction of action potential synapse - cell to cell contact presynaptic terminal - neural output microtubule - where storage vesicles attach to mitochondria - high density - active transport postsynaptic terminal - neural input Types: electrical synapse - gap junctions directly connecting pre- to post- chemical synapse - vesicle package neurotransmitter to cleft ** Two types, why? Di erent tight control mechanisms Mechanism action potential vesicle to SNARE docking protein Ca2+ channel ood presynaptic Ca2+ bind to synaptotagmin exocytosis - release neurotransmitter Ca2+ pumped back vesicles mem recycled - prevent presynaptic mem expansion Neurotransmitter checklist: - present in presynaptic - released upon presynaptic stimulation - enter extrcell uid and mimics presynaptic stimulation - have removal mechanism: inactivation or reuptake Pathway: motor neuron presynaptic release acetylcholine into synapse binds to acetylcholine receptor in muscle ber use ionotropic mechanism ux Na+, increase action potential 9 fl fi fl ff ff fl fi ff fi fi fi fl  Ca2+ released from SR decrease action potential Ca2+ expose myosin binding site on actin muscle contraction signal is terminated by acetylcholinesterase Ca2+ reuptake into SR, costs ATP myosin unbinds from actin muscle relaxes Types of Neurotransmitters small amines and amino acids neuropeptides - water soluble, no carrier Neurotoxicity Botulism - botulinum cleave SNARE docking proteins vesicles cannot dock, neurotransmitter not released lose muscle control Latrotoxin - from Black Widows, keep Ca2+ channels open myosin binding site in actin kept expose muscles uncontrolled contraction = spastic paralysis Organophosphates - insecticides that inhibit acetylcholinesterase acetylcholin kept bound to muscle bre increase Na+ and action potential increase Ca2+ muscle contraction - spastic paralysis 3. Endocrine signalling - produce chemical signals/ hormones short distance: autocrine and paracrine via interstitial uid long distance: endocrine via bloodstream or hemolymph endocrine glands - release hormones neuron releases to endocrine - neurohormones Types of Hormones 1. Steroid - by gonads and adrenal cortex from cholesterol lipid soluble, di use across cell mem require water soluble carrier protein (i.e. globulin, albumin) a. Cort - by adrenal cortex, ‘stress hormone’, slow to react i.e. salmon - peak cortisol levels 1-2hrs after stress event i. Mineral corticoid - a ect ion imbalance = adrenal issues b. Aldosterone - by adrenal cortex, slow to react regulate ion levels by reabsorbing Na+ and excreting K+ c. Testosterone by gonads d. Estradiol by gonads 2. Neuropeptide - amino acid neurotransmitter from CNS neurosecretory cells packaged into vesicles for exocytosis water soluble, no carrier required 10 ff ff fi fl  a. Vasopressin AVP - type of ADH by pituitary gland, retains water increase aquaporins AVP bind to kidney receptor aquaporin-2 inserted from vesicle storage to mem provide water channel - absorb water aquaporin-3 move water from cell to blood b. DH 3. Amine hormones - by adrenal medulla and thyroid gland generally water soluble a. Catecholamines - by adrenal medulla, water soluble eph, noreph, dopamine b. Thyroid hormones by thyroid gland, lipid soluble derived from Tyr and requires iodine c. Melatonin by pineal gland, lipid soluble derived from Trp 4. Lipid messengers - lipid soluble a. Eicosanoids - paracrine signalling derived from arachidonic acid in ammation and pain short half life i. Leukotrienes - by lipooxygenase pathway ii. Prostaglandins - by COX pathway pain perception target for NSAIDs ibuprofen - blocks prostaglandin production 5. Gas messengers - lipid soluble paracrine signalling, short half life NO - by NO synthase vasodilator, to increase blood ow Control of Endocrine Secretions Neurohemal organ - contains neurosecretory cells Neurosecretory cells - CNS neurons that exocytose neurohormones/ neuropeptide Pituitary gland - (below hypothalamus) Hypothalamus synthesize AVP, CRH and oxytocin > neurosecretory cells > posterior pituitary (neurohypophysis) > HPA > exocytosis to blood Epithelial endocrine cells - non neuronal - shorter Endocrine synthesize hormones > neurosecretory cells > anterior pituitary (adenohypophysis) > HHP > blood stream Direct acting - to non endocrine tissue Tropic - continue pathway to endocrine tissue 11 fl fl  Why are shorter paths (HPP) important?? Prevent circulation of ant. pituitary or non neural speci c signal into blood stream Adrenal gland - stimulated by Sympathetic PNS ** analogous forms of adrenal gland near the kidney teleost - head kidney di used mammals - discrete adrenal cortex - outside, composed of interrenal tissues, secrete steroids: aldosterone, CORT adrenal medulla - inside, composed of chromatin secrete catecholamine: epi, norepi i.e. dog sh sharks and frogs - mostly norepi mammals - mostly epi 4. Stress Response stress - factors that disrupt homeostasis (abiotic or biotic), timescale (acute or chronic), evolutionary adaptive 1º response - increase catecholamines and CORT 2º response - e ect to target tissue (expression, activation, pathways) 3º response - physiology and behaviour (metabolism, anti predator) adrenal medulla secrete epi and norepi (rapid response) Why? Direct to blood via aquaporin vasodilation - increase blood ow increase HR and resp stimulates Glc = energy inhibit insulin increase AVP, CRH ACTH released in blood adrenal cortex - secrete CORT (slow response) - Why? synthesized on demand, need receptor protein and fat = energy inhibit gonads secretion and thyroid hormone (amine hormone) **very high CORT levels due to chronic stress is harmful = atrophy ; thus, release cytokines to regulate immune response and in ammation Factors: Genetics, Sex (higher female), social hierarchy, pollutants, parental (maternal-derived) Types of CORT glucocorticoids - physiological processes, kept at low for optimal mineralocorticoids - ion homeostasis Receptors GR2 - higher a nity to CORT (unstressed) GR1 - binds CORT (stressed) - require higher levels to bind Transactivation - CORT level with 50% of receptor activity OSMOREGULATION blood and hemolymph uid volume tight regulation ion levels - active and passive transport pH changes a ect O2 binding 12 ff ffi ff fl fl fi ff fl fi  osmoregulation - water and ion content in body Renin angiotensin aldosterone pathway RAAS renin - enzymes produced in nephrons convert angiotensinogen to angiotensin I angiotensin coverting enzyme: convert angiotensin I to II angiotensin II - increase aldosterone (reabsorb Na+, excrete K+) and AVP ADH (reabsorb water) ref. DH and ADH neuropeptides - water levels Aldosterone and mineralocorticoid steroids by adrenal medulla - ion levels Dehydration angiotensin II binds to osmoreceptors in brain detects osmolarity changes in spinal uid that surrounds hypothalamus thirst centre increase motivation to drink Increased Na+ Na+ accumulates in blood, increasing blood volume ANP released to increase kidney ltration thru vasodilation (increase ow) decrease renin release = decrease aldosterone (x Na+ reabsorbed) and AVP ** Net decrease in Na+ and increase in water Diadromous sh with euryhaline (wide range of tolerable salinities) life cycles Catadromous - SW spawning Anadromous - FW spawning i.e. salmon Cortisol (CORT) level - by head kidney (adrenal cortex of sh) - osmoregulate ‘salt water adapting hormone’ SW increase Na+/K+ ATPase ions tend to move in, and water escape gills alter by excreting ions and drinking more water Prolactin - by pituitary - osmoregulate ‘freshwater adapting hormone’ FW decrease Na+/K+ ATPase ions tend to move out and water to move in gills alter by intake of ions and pee water ** cortisol decrease if prolactin increase (switch) v.v. Smolti cation - physio and morpho changes to prep anadromous sh to move FW to SW cannot wait in estuaries before gills alter - high predation risk cortisol and ion levels upregulated ahead of time (May), since it is slow acting cortisol up, prolactin down Migrating back from SW to FW as adults prolactin increase depends on distance from spawning river cortisol down, prolactin up Challenges: diseases and parasites, migration stretches while starving Adaptation: expression of CORT increase over time 13 fi fi fi fl fi fi fl  CIRCULATORY SYSTEM Open single chambered heart hemolymph in discrete vessels less resistance goes to sinuses (larger channels receiving from discrete vessels) lacunae (reservoir) with anastomosing beds to tissues gas and material exchange Closed blood stays within the vessels higher resistance RBC WBC plasma O2 CO2 hormones carriers ions higher pressure required multi chambered heart Heart primary mechanism to perfuse blood around the body others: elastic recoil of arteries smooth muscle contraction skeletal muscle movement valves - prevent back ow brous connective tissue - proper ow from atrium to ventricle (not directly to ventricle) pacemaker - receive signal from myogenic signal allow atrium to empty rst before ventricle contracts myocardium - muscle of the heart, regulate force of heart beat spongy compact axillary hearts - perfuse blood in localize regions that pressure cannot reach i.e. shark tail - collagen bulb i.e. cephalopods - has hemocyanin that is less e cient in carrying O2 Arteries - carries oxy (red) blood away from heart to systemic tissues thick walls = rigid for pressure dampening elastic recoil - contraction pushes blood in - expand and store potential energy relaxation - stored potential energy pushes blood Laplace’s law: Tension = r∆P bigger radius and higher pressure increase tension ** small arteries, small radius = decrease tension microcirculatory beds Capillaries - di usion of materials to and from the tissues; maintain uid balance between plasma and interstitial uid may only be as wide as a single RBC fenestrated aquaporins high in skeletal muscle, myocardium and brain Straling forces - state of hydrostatic pressure Pc decrease from arterioles to venules = lters plasma Pi increase from arterioles to venules = reabsorption Net P = Pc - Pi Osmosis - movements of liquid from high to low across a membrane high solutes = high osmotic pressure = likely to take in water 14 fi ff fl fl fl ffi fi fl fi  π plasma > π ISF since ISF is non permeable to solutes Net π = π plasma - π ISF **Net uid movement = Net P - Net π Anastomoses - direct connection of arterioles and venules, bypass capillary bed Veins - carries deoxy blood towards the heart endothelium - lining of the vessels - help with clothing, contraction and relaxation, secretion Heart as a pump: 5 main phases Atrial systole (contract) - blood out A.pressure > V.pressure tricuspid and bicuspid open semilunar closed Ventricle relax - blood in Isovolumetric contraction Ventricle starting to contract all valves closed no ow V.pressure < A.pressure Ventricular ejection ventricle contract - blood out tricuspid and bicuspid close semilunar open aorta and pulmonary artery - blood in V.pressire > A.pressure Isovolumetric relaxation Ventricle starting to relax all valves closed no ow A.pressure > V.pressure Ventricular lling Atrium relax; ventricle relax - blood in tricuspid and bicuspid open A.pressure > V.pressure Heart Rates Neuroendocrine control sympathetic - increase HR; parasympathetic - decrease HR via pacemaker myocardium - force of contraction Ref. Motor neuron contraction/relaxation pathway depolarization - contract polarization - relax Myogenic control - initiates in the muscle direct cell signalling - gap junctions uses pacemaker Blood pressure - driving force to perfuse blood by the heart myocardium Systole Contraction - allowing blood out 15 fi fl fl fl  Diastole Relaxation - allowing blood in Hydrostatic pressure - pressure exerted by blood in on vessels, which drives blood ow as an e ect of gravity above the heart decrease 1.3cm = ± 1mmHg below the heart increases Total uid energy of blood (E) = (1) potential energy from heart H + (2) kinetic energy K + (3) potential energy from gravity G Poiseuille’s law = Rate of blood ow (F) = pressure di erence (∆P) / resistance (R) ∆P increase = F increase R increase = F decrease assumes laminar ow **if turbulent, ∆P increase Why? Increase RBCs in blood Resistance vessel length ** vessel radius only variable Thus, vasodilation/constriction a ects BP viscosity (hematocrit) Aorta (big) > capillaries (small) > veins (big) Adaptive? Allow exchange to occur slow down CASE STUDIES: Blood ow in legs = potential energy from heart and gravity (1+3) If organism is laying down = potential energy from heart (1) Ventricular ejection = blood ow from ventricle to aorta although V.pressure > A.pressure (2) Gira es = high potential from gravity; has strong ventricles and high BP to o set and push blood (3) high BP o set by thick vessels tight skin promote ltration of plasma and reabsorption by ISF Exercise - increase cardiac output to sustain O2 demand vasodilator in active muscles vasoconstrictor in others Bar-headed Geese - Himalayan migration large lungs large capillary beds in ying muscles mitochondria close to capillaries Open CS - Hemolymph Pigments via Metalloproteins hemoglobin - red chlorocruorins - green hemocyanin - blue/colourless, less e cient for O2 i.e. horshoe crab blue blood(hemocyanin) detect bacteria in vaccines hemerythrins - reddish violet/colorless Heart Rates external: temp, hypoxia, contaminants — because ectotherms neurohormones: CCAP - cardio accelerator similar to vasopressin Octopamine - similar as norepi, enhance myocardia function Proctolin - enhance contraction not a ected by TTX pu er sh - blocks ion channels and contraction 16 fl ff fl ff fl fl fi ff fl fl ffi ff ff fi ff fl ff ff CLOSED SYSTEM - more resistance - higher BP Birds and Mammals - endotherms (high MR for aerobic) Too much heat - anaerobic = increase [lactate] 4 chambered divided Left - oxy Right - deoxy Systemic and pulmonary completely separated Systemic have higher pressure and resistance Pulmonary has lower pressure and resistance Alveoli gas exchange of pulmonary - kept dry Compact only with coronary circulation Require Neuroendocrine or Myogenic control Teleost Fish - ectotherms (low MR) 4 chambered undivided Systemic and pulmonary not separated Compact and Spongy - little to NO coronary circulation CASE STUDY: Salmon More compact = greater migration e ort Conus arteriosus - channel connecting ventricle and bulbus arteriosus Bulbus arteriosus - connect ventricle to aorta and arteries Elastic pressure reservoir Myogenic control Elastic recoil increase potential to o set small heart Gills - gas exchange to tissues ** good for tissues bad for the heart Spleen - reservoir for RBCs **If taken out - decrease aerobic capacity vs Sham Surgery still have RBCs = viscosity = resistance High BP to o set 17 ff ff ff  Air/Mouth Breathing Fish - Eel Parallel (not common for sh) Systemic and pulmonary not separated Gills - gas exchange to tissues Mouth - O2 intake Both leads to veins, heart gets more O2 = better performance Gut Breathing - cat shes Parallel (not common for sh) Gills - gas exchange to tissues and gut Gut/swimbladder - O2 intake Both leads to veins, heart gets more O2 = better performance Intermittent air breathers - lung sh Ancestor to terrestrial animals Incomplete septum Spiral fold - proper blood ow Left - oxy Right - deoxy Path of deoxy blood In water, Gills - gas exchange to tissues via ductus In land, Lung - gas exchange to heart to tissues 18 fi fi fi fl fi  Amphibians 3 chambered - 2 separate atria and ventricle Systemic and pulmonary separate Di erent BP in those circuits Distribute blood ow to those circuits Lungs - gas exchange to heart Skin - O2 intake to heart Left atrium - oxy Right atrium - deoxy Mix in ventricle to spiral fold - proper blood ow Systemic system conus arteriosus Left - tissues Right - lungs/skin Compact and Spongy -coronary circulation Turtles, Lizards and Snakes 5 chambers - 2 separate atria + 3 incomplete ventricle NO conus arteriosus Left atrium - oxy Right atrium - deoxy Mix in Ventricle Left - tissues/skin Right - lungs Lungs- gas exchange Skin - O2 intake *in some turtles only When under water: pulmonary has resistance, Deoxy shunted to systemic and skin (alternative gas exchange) Komodo dragons 3 chambered heart Functional atria septum that directs oxy blood to tissues and deoxy to lungs via di erence in pressure Pulmonary - always less pressure and resistance Systemic - always more pressure and resistance 19 ff ff fl fl  Crocodilians 2 chambers Left heart - oxy Right heart - deoxy Left ventricle - tissues Right ventricle - lungs/tissues (if under water) 2 aortas uses ap valve closed - lungs open to tissues Connected via foramen of panizza To by pass pulmonary when under water Systemic and Pulmonary mix when under water Annelids(inverts) More than one heart (anterior) Greater blood ow -anterior Sluggish - posterior Cephalopods - Octopus (inverts) Gills - gas exchange Systemic heart received oxy blood Tissue sends deoxy blood to branchial hearts to gills High BP for: Propulsion mobility - aerobic Hemocyanin - less e cient for O2 Needs higher concentrations to o set Need axillary hearts Higher cardiac output OPEN CIRCULATORY - less resistance, lower BP Crustaceans and Molluscs Single chamber heart with Ostia to discrete vessels To Lacuna with anastomoses - material exchange with tissues Pumps to sinuses To gills - gas exchange To heart Neurogenic control Cardiac ganglion Pacemaker - Depolarizes - contract Polarization - ligaments pull back = vacuum — relax 20 fl fl ffi ff  Insects O2 intake does not require CS — only from breathing CS similar for crustaceans, but only for hormones and nutrients Guest Lecture FPW e ects on Fish Cardio-Resp Systems Embryo/Whole animal level e ects spinal deformation yolk sac swelling pericardial swelling ** decrease HR and MR ** decrease swim performance and aerobic scope Tissue Level decrease gene expression of compact myocardium Cellular Level **decrease amplitude and speed cardiomyocyte contractile 21 ff ff