Circulation & Gas Exchange PDF

Circulation & Gas Exchange: Why do cardio? Cellular Respiration Aerobic process using organic materials + O2 to release ATP, CO2 and H2O; in eukaryotes occurs in mitochondria Single-celled organisms use simple diffusion to access metabolic molecules Poriferans...

Circulation & Gas Exchange: Why do cardio? Cellular Respiration Aerobic process using organic materials + O2 to release ATP, CO2 and H2O; in eukaryotes occurs in mitochondria Single-celled organisms use simple diffusion to access metabolic molecules Poriferans Relatively small/simple animals can maximize surface area exposure for material exchange via gastrovascular cavity Cnidarians, platyhelminthes Circulation - transport materials Larger organisms require an efficient delivery system: a cardiovascular system combining specialized circulatory and ① respiratory structures ⑤ ② Requires heart (pump), vessels, & circulatory fluid Open: circulatory fluid (hemolymph) not -good for things small exclusively contained in vessels; lower energy demands bugs in Arthropods, some molluscs (bivalves , gas tro pods Closed: circulatory fluid (blood) entirely contained in vessels; higher energy demands Vertebrates, annelid worms, some molluscs (efficient ; controll where blood goes huge energy demand  s chambered heart Ctrls blood flow separate Vertebrate Circulatory Systems circuit on/off to lungs pulmonary ↑ systemic ~ Cskip over pulmonary circuit) & Circulatory fluid = blood away heart - Vessels = arteries, veins, towards neart - capillaries gas exchange Heart = 2-, 3-, or 4-chambered pump powering single or double circulation (pulmonary & systemic circuits) 3-chambered hearts are useful to reduce circulation to the lungs when submerged I Lower vessel pressure (1 pump Higher vessel pressure (2 pumps w/ Skin frogs can do gas exchange per complete cycle) per complete cycle) pulmonary > - to lungs good systemic for temp. > body - to underwatter or gas excrange wiskin  on Exam !! Pulmonary > lungs - rV interior > - rA- > => trunk ↓ pulmonary I vein et aorta =er base Human Heart Anatomy & Physiology I Chambers: 2 atria, 2 ventricles pulmonary osmit mink I superio interior pill Vessels: 2 arteries, 6 veins - ta & vein 4 pulmonary lef + A Valves: 2 AV, 2 semilunar ↳ maintain I way blood flow Cardiac output (CO) = stroke volume (SV) x heart rate (HR) SV = volume/contraction # ordered a HR = contractions/minute AV value mining ! [ closed system semilunar btwn Adv - no bidirection no cordae tendonne ex. aortic value I thicker ; must a pex I pump blood everywhere failure of value else murmur > S - heart Cardiac Conduction System tells all musires Contraction controlled by SA - to contract/relax node (pacemaker), AV node - cause at contracts a peX Contraction = systole, relaxation = diastole Chelps chambers empty ventricles recovery a+ hical Blood Vessels Tissue more u/ Arteries: away from heart; thicker, more -dealing pressure muscular, no valves (pressure from heart maintains one-way flow), pulse present (esp. in large arteries) Arteries ->arterioles -> capillaries Veins: toward heart; thinner, less - doesn't deal w/ muscular, valves possible, no pulse pressue Capillaries -> venules -> veins of increasing I ( diameter single red blood cell diameter ; kill the pulse/pressure lo+ Skeletal muscle squeezes blood up veins us values as points stopping blood moves slowly in veins Blood Pressure Regulation arteries dilating diverting Pressure must be maintained at reasonable levels via bloodes ↑ int negative feedback High blood pressure? Vasodilation: relax arterioles; more blood ‘out of circulation’ lower blood pressure Low blood pressure? Vasoconstriction: restrict arterioles; more blood in major arteries raise blood pressure Shifts in blood flow can be result of exercise (diverting blood to muscles; modify by increased heart rate), injury (blood loss reduces blood volume & pressure; compensate by plugging injury, diverting blood flow) Blood tends to pool in lower extremities due to gravity (also a problem for very tall animals); valves, skeletal muscle contractions & higher blood pressure can compensate  Capillaries & Lymphatic System systemic capillaries pressure Capillaries: smallest diameter low vessels, highly permeable & numerous for material exchange with tissues; entry into capillary / beds controlled to maintain blood pressure high pressur mostly H20 Exchange is primarily passive; C leakage is common & requires ‘clean-up’ system (lymph, supplements - collected & returned to circulatory sys circulation by lymphatic system) Edema = fluid collection in tissue (failure of lymphatic system) How to get rid of nonpolis substances ? Iv Cleans up thirds are intertwined w/capitchies  Lymphatic filariasis (elephantiasis); edema due to lymphatic damage induced by nematode worm & edma leg : nematode worm gets into yuphetic system can't drain effectively  Blood connect ive Function: transport [respiratory gases, nutrients, hormones, immune - cells, wastes] we Plasma (~55%): liquid component; transport dissolved substances, > - giucose maintain osmotic pressure, pH > - maintained by buffos; CO2 + Itz0 > - carbonic acid Cells (~45%) ↳ regulated by proteins RBC Erythrocytes (red blood cells): small, numerous, non-nucleated biconcave cells to transport oxygen (& minimal CO2) no nucleus in RBC ; pigment maximize of carrying cont. Fe < Use hemoglobin to bind O2; iron causes oxygenated blood to be bright red environ. Production controlled via erythropoietin (released by kidneys) Higher based on altitude > - moreRBC compensaaa to WBS Leukocytes (white blood cells): large, nucleated immune cells (5 categories) Platelets: cell fragments used in clotting response ↳ mainly for clotting  RBC bleeding is good too much = ↳ leaches treatment ; & suck blood to help swelling in controlled manner phagocytosis Im - eater > - - antibodies specific/target eater & Zworm parasites ( localized mostly erthycytes inflamation in is good > - draws WBC * RBC to injury  Gas Exchange -largely passive ; driven by pressure gradients Gas exchange is the process of collecting O2 from and releasing CO2 to the environment Oxygen is used in cellular respiration to make ATP with CO2 as a waste product; cellular respiration is NOT respiration (breathing) Process works via pressure gradients (passive transport) Dalton's > - Partial pressure = pressure exerted by a specific gas in a mix; natural movement from higher -> lower pressure Oxygen is ~21% of the atmosphere; at sea level pressure is 760mmHg thus partial pressure of oxygen is 0.21 x 760mmHg = 160mmHg -partial pressure o2 of If pressure changes (like with altitude or depth) partial pressure changes If atmospheric pressure on Denali (~20,000ft) is ~380mmHg, 21% O2 is just 70mmHg Partial Pressure Con’t Oxygen dissolved in water also has partial pressure value BUT concentration differs CO2 dissolves - better in H20 reason / diff mediums roblemsinT. why gills concentrations so effcient = equal 20 are not carbonic hard to dispel Partial Pressure Con’t H20 important for diffusion to occur Also, warmer, saltier water holds less oxygen Respiratory systems must adapt to conditions they are used in (medium, concentration, pressure) Air is ‘easier’ to breath than water (higher O2, less viscosity) But gas exchange requires moisture for effective transport (not an issue in aqueous environments) Respiratory Surfaces every cell for + nemselve Regions specialized for gas exchange (respiratory surfaces) vary: Individual cells: small, simple animals where all of body is close to surface ↑ Skin: moist environments, small bodies/low demands, efficient transport - low energy not much specificity  Respiratory Surfaces Con’t ① Gills: aquatic animals in low O2 environment; extensive surface area and use of water as structural support; ventilation to encourage countercurrent flow high efficiency differencesa - getting of (gas exchange) in to Running water opposite blood to maximize exchange dre in concentration & S operculum in only fish Isoits requires movement constant ! (max to , abs JA) 02  when O2 levels are higher Respiratory Surfaces Con’t Bugs get bigger ① ~ Hollow tubes win body Tracheole systems: insects, spiders (with open circulatory systems) Branching tube system that runs throughout entire body Highly efficient in high O2 environments and with small body size Muscle contractions can pump air through trachaea (similar to breathing) C entrances to the tracheal system in - insects open circulatory  Respiratory Surfaces Con’t terrestrial vertebrates ③ Lungs:mainly some vertebrates (mostly - requires circulatory reptiles/birds, mammals; sometimes system used in conjunction with other respiratory surfaces) Specialized organ requiring circulatory system to distribute respiratory gases throughout body Convergent evolution! Spiders have book lungs (gills that act in air  on exam - - Overview of Human Respiratory System Bronchi-roads for gases ① a projects disp netwarming warm one ② 3 - not a balloon ; of holes connections lots to max SA to lower parts I place of only exchange Lamazing - sites of gas exchange control + structure ; make different sounds air cannot down epig mucosal elevator push - last diech effort to get pathogens deposit into esophag. before reaching lungs  ? breathe virties do Hour Breathinde a o birds ' Ventilation (Breathing) ↑ max. to option #1 Positive pressure breathing: pushing air - “swallowing air” (amphibians) into system option #2 Two-cycle breathing: air sacs allow one-way airflow (birds)  down breathe in > - diagphragm Ventilation Con’t breathe out > - diagphragm relax do ? humans what ~ Negative pressure breathing: pulling air into lungs by creating lower pressure via muscle contractions (diaphragm + intercostals) (mammals) NOTE: this means exhaling is normally passive  Breathing Issues Sac lungs are not very efficient exhale/innale Tidal volume (volume of air > - inhaled/exhaled normally) is far potential max of air below maximal lung capacity (vital > - capacity) and you cannot exhale all air (residual volume) ( Surfactant helps prevent surface tension in alveoli, preventing collapse likely less to its attach to self prevents lungs for collapsing premies don't have surfactant production > - collapse every breath H20 has surface tension => can potentially collapse lungs How to deal Pneumothorax...?  - normal breathing tidal volume - keeps lungs slightly inflated (in spiration reserved volume Breathing Issues Con’t Humans don't do countercurrent flow extract max. amount of @ ↳ use mult. alveoli to possible Oxygen extraction is inefficient (no countercurrent flow); hemoglobin has affinity for oxygen, but not as high as some respiratory pigments (ex: myoglobin, fetal hemoglobin) < high] [low] ↓ ↑ [high] [low] & tissue must have high affinity (myoglobin) o to take for 02 away from RBCs myoglobin > hemoglobin aft Final Thoughts first not hollow lungs Blood doesn’t have to be red, and lungs aren’t balloons I - - nemerythrin un