Invertebrate circulation
1. No circulatory system: simple diffusionarcher, eubacteria, protista, fungi, invertebrates Porifera, cnidaria, Platyhelminthes, Nematoda, Rotifera2. Open circulatory systemmollusks, arthropoda, echinodermata insects: have several tubular hearts that pump *hemolymph through single dorsal vessel.from there, moved into sinuses: small, open-ended chambers sinuses dump hemolymph to hemocoel: large cavity tricky to return to heart, muscular contractions and locomotion allow movement of hemolymph which can re-enter relaxed heart through Ostia: openings *can't be differentiated from blood (bc it has nutrients) + interstitial fluid (lies b/w cells) insects also have spiracles: tiny holes all over body, allows air to pass into tracheal system (responsible for gas exchange)means life is heavily influenced by [O2] in atmosphere than those w closed3. Closed circulatory systemannelidaexchange gases b/w cells + env via fluid medium (blood)extremely efficient in moving fluid: have pumping heart that pushes blood through closed blood vessels annelids: (segmented worms) have aortic arches: multiple hearts which pump blood in a circuitblood moved toward front of worm via dorsal vessel blood moved to back of worm via ventral vessel
vertebrate circulation: 2 chambered
closed! primary/ true heart chambers: atria and ventricles, responsible for receiving and pumping blood ventricles are stronger than atria bc they pump to hole body vs pumping to ventricle 2 chambered hearts: 2 primary chambers: 1 atrium 1 ventricle only pumps deoxygenated blood (oxygenated blood does not enter heart) single circulation hearts: blood passes thru heart 1 time before sent out to organs works well for chordates w closed that live in water: fish!fish (simple heart) have secondary heart chambers: help primary receive and pump blood,
vertebrate circulation: 3 + 4 chambered
3 primary chambers: 2 atrium + 1 ventricle ex: amphibians + reptiles (poikilothermic)mix deoxygenated + oxygenated blood in ventricle double circulation hearts: blood passes through them twice before sent to organs4 primary chambers: 2 atrium 2 ventricle ex: birds + humans (homeothermic) double circulation heartsBUT NO MIXING of deox + ox
Pulmonary circulation + Human heart: right
PULMONARY CIRCULATION: deox blood to lungs so it can be oxygenated 1. right atrium accepts deoxygenated blood from the body via superior and inferior vena cava (largest veins in human body)2. blood pumps through tricuspid (atrioventricular) valve into right ventricle 3. right ventricle pumps deoxygenated blood thru pulmonary semilunar valve into pulmonary arteries4. pulmonary arteries take deoxy blood away from heart to lungs for gas exchange 5. pulmonary veins carry oxygenated blood from lungs toward heart to left atrium Atrium: superior VC: returns deoxygenated blood from body parts above heartinferior VC: from below the heart AV valve: prevents back flow of blood from ventricles to atria attached to papillary muscles via chord tendineae (stringy tendons) papillary muscles contact: closes AV valve: preventing valve inversion during ventricular contraction ventricle: semilunar valve: 3 cusps, ensures one way blood flow of deoxygenated blood pulmonary arteries: right one takes blood to right lung and vice versa RA: also includes sinoatrial node and coronary sinusSUMMARY: Vena Cava - RA - tricuspid valve - RV - pulmonary semilunar valve - pulmonary arteries - lung - pulmonary veins - LA
Systemic circulation + Human heart: left
SYSTEMIC CIRCULATION oxygenated blood to tissues for use of oxygen + nutrients in blood, becoming deoxygenated at the tissues * has a higher resistance to blood flow even though blood volume is the same bc there are more vessels to perfuse in 1. left atrium accepts oxygenated blood from pulmonary veins 2. LA pumps through bicuspid 2 cusps / mitral (AV) valve into left ventricle3. LV forcefully ejects blood through aortic semilunar valve 3 cusps and into aorta 4. aorta circulates ox. blood to tissues, blood becomes deoxygenated 5. vena cava returns deoxygenated blood to right atriumleft ventricle: most muscular chamber of heartaorta: largest artery in the body, highest blood pressure of any vessel in heartbc it is directly connected to source of blood pumping pressure (LV) + receives full blood volume of ventricular contraction SUMMARY: LA - bicuspid/mitral valve - LV - aortic semilunar valve - aorta - tissues - vena cava - RA
Coronary circulation
1. coronary arteries branch off the aorta and provide oxygenated blood to heart's myocardium 2. cardiac veins drain deoxygenated blood from myocardium to right atrium via coronary sinusmyocardium: muscle layer of the heart which contains cardiomyocytes endocardium: layer beneath myocardium, formed from endothelial cells lining the inside of the heart's 4 chambers pericardium: sack of fluid surrounding heart, multi-layered, protects heart serous pericardium: the fluid in the sack, made of proteins which acts as lubricant for the heart + allows movement as heart beats, reducing friction coronary sinus: small opening in right atrium
Signal transduction + action potentials
action potentials are propagated among cardiomyocytes of myocardium for smooth, well-timed contractions intercalated discs: contact points b/w adjacent cardiomyocytes that connect them. contains: a) desmosomes: small protein that stitch/adhere cells togetherb) gap junctions: protein tunnels that connect cytoplasms of adjacent cells, allowing ions and molecules to pass directly (+ propagate action potential) syncytium: connection of many heart cells together, crucial to coordination of heart function: unification of heartcardiomyocytes have automaticity: action potentials are generated without external nerves needing to initiate the action potentialsinoatrial node (IN RA): has greatest automaticity, most likely to reach threshold to stimulate action potentials to other heart cells: pace maker of the heart, fires first and sets rhythm heart can function independently but is influenced by nervous systemsympathetic nervous system: cause heart to beat fasterparasympathetic: cause heart to beat slower
human cardiac cycle
SA node wants to beat fast but is innervated by parasympathetic vagus nerve (which extends from medulla oblongata) this exerts default signal to slow down the SA node to 60-90 BPM1. SA node reaches threshold + sends wave of depolarization thru both atria 2. causes them to contact and send their blood to ventricles 3. eave reaches the bottom of RA + contacts atrioventricular node (AV) which adds brief delay 4. AV Node sends electrical signal to bundle of His 5. bundle of HIS carries signal to base of heart by right and left bundle branches6. bundle branches pass the signal through purkinje fibersAV node: adds the brief delay b/w atria + ventricle contraction, loss of function would cause A + V to contract at same time, ventricles would not fill completely: not effective bundle of his: located in inter ventricular septum: separated the ventricles Purkinje fibers: located in walls of ventricles, ensure coordinated contraction of both ventricles
Diastole/Systole and Heart sounds
phases of cardiac cycle determined by ventricular contractionsystole: ventricles eject blood into arteries, bp is highest in arteries, between lub + dubdiastole: right after end of ventricular contraction, myocardium is completely relaxed, BP is lowest in arteries, between dub + next lub lub: due to ventricular contraction, LA + RA are relaxed, LV + RV are contracting semilunar valves open + atrioventricular valves snap shutdub: due to atricular contractionLA + RA are contracting, atrioventricular valves open + blood fills LV + RV which are relaxed. semilunar valves are closed.
measuring cardiac cycle
Electrocardiogram: sensors at specific regions of heart that can "listen" to depolarizations/electrical signals of the heartinforms underlying heart conditions: dysrhythmias (bad rhythm), A + V hypertrophy, myocardial infarction (tissue death), improper conduct. of Action PotP wave: both atria depolarizingQ wave: depol thru inter ventricular septum: initiates ventricular depol R wave: tallest, depol through both ventriclesS wave: completion of ventricular depolQRS complex: broader view of ventricular depolT wave: ventricular repolarization atrial repolarization is hidden by QRS complex
Heart function measurements
1. HR: > 100 bpm= tachycardic < 60 bpm= bradycardic2. stroke volume: volume of blood pumped from the heart w each beat (generally LV)SV=ESV-EDVEnd-systolic volume: amount of blood that remains in ventricle following contraction End-diastolic volume: amount of blood in ventricle before contraction 3. Cardiac Output: volume of blood pumped by heart in 1 min CO=SV x HR4. total peripheral resistance: amount of resistance blood faces when flowing through vasculaturevasoconstriction: constricting blood vessels, increases TPR + BPvasodilation: widening of blood vessels, decreases TPR + bp 5. Blood pressure: systolic: highest bp in arteries when ventricles contact, numeratordiastolic: bp of arteries b/w beats, denominator auscultation: measuring these using a stethoscope + sphygmomanometer 6. mean arterial pressure: average during one complete cardiac cycle, better indicator of bp MAP= CO X TPRMAP = (HR X SV) X TPR
Blood vessels intro
transport blood to + from heart in closed systemhollow tubes with three layers surround lumen (central pore)tunica intima: surrounds lumen of blood vessel, contains endothelial cells that reduce friction of blood flowing thru lumentunica media: above intimate, contains smooth muscle cells that can control diameter of vessel to manipulate blood flowtunica extrema: above media, contains collagen proteins that protect vessel + nerve fibers + elastin proteins
Blood vessels: The As
oxygenated away from heart except pulmonary + umbilical: deox. away from heart most elastic but hold less bloodelastic bc of thick tunica media which can change diameter in response to hormones (or thermoregulatory needs) + high amounts of elastin proteins which allow walls of vessel to flexconstriction: maintain body temp when its cold, prevents blood from flowing close to skin so temp of blood doesn't changedilation: cools body down, blood flows closer to skin + releases heatarteries: BP is highest, elasticity allows them to absorb and even out (moderate) bp arterioles: branch off arteries, smaller diameter. resistance vessels: high resistance to blood that flows thru them, bp drops the most
Blood vessels: capillaries
capillaries: brings nutrients (sugars + aa) to tissues + removed waste (CO2 + urea)smallest diameter vessels branching off arterioles and connecting to venulesb/w arteries + beins one endothelial cell thick: only tunica intimate covered by thin basement membrane: provides extra support have fenestra: pores that increase what can diffuse in/out of cap arterial end: forces plasma out of vessel bc of high hydrostatic pressure: how nutrients go to tissuesvenous end: wastes are pulled back in bc of high oncotic (type of osmotic) pressure ([protein] is high so water + waste flows back in) waste is sent to venules: vessels that connect capilaries to veins
Blood vessels: veins
take blood back to heart, wider than arteries (hold most of body's blood) have much less smooth muscles, under less pressure veins: high capacity: capacitance vesselscontains valves: ensures blood flows toward the heart bp is lowest here so pumps are used to move blood. skeletal muscle pump: skeletal muscles contract + relax, squeezing veins forcing blood to move forward (bc of valves) towards heartrespiratory (abdominothoracic) pump: during inspiration, abdominal pressure increases: squeezes veins, moving blood forward + thoracic pressure decreases: creates negative pressure in vena cava + right atria: causes them to explain + pull blood inside
Portal systems (VENOUS)
cap bed is connected to another cap bed through a portal vein (includes venules + veins in b/w)allows quick diffusion (shunting) of concentrated blood from different tissues hepatic portal vein: shunts blood from digestive tract (++) to the liver, allowing immediate filtration of things we consume after absorption hypophyseal portal system: hormones from hypothalamus to enter anterior pituitary w/o going thru heart, quicker + prevents dilution of hormones via systemic circulation
Blood clotting cascade
Positive feedback mechanism. 1. tissue is damaged, tearing blood vessel walls + exposing collagen within the wall2. exposed collage in circulating blood causes platelet activation (recruits more), causing platelets to adhere and aggregate where rip has occurred: forms platelet plug3. activated platelet release thromboplastin (tissue factor) which converts inactive prothrombin to thrombin 4. thrombin converts precursor fibrinogen to fibrin which polymerize with each other + attach to platelets to from hemostatic plug (blood clot)'* vitamin K: important in manufacturing of blood clotting factors like prothrombin, made and modified by symbiotic bacteria in large intestines
Components of blood
connective tissue: cells surrounded by matrix 1. plasma: water proteins, nutrients + hormones 3. leukocytes: immune cells 3. platelets (thrombocytes): cell fragments w no nucleus (enucleate) megakaryocytes (large bone marrow cells) are precursor to platelets, important for clotting4. Erythrocytes (RBC): enucleate, flexible (can squeeze thru small caps + deliver O2)contains very little within cytoplasm maximizing space, contain millions of hemoglobin molecules: quaternary protein w 4 subunits, each one tightly associated with non-protein heme groupeach heme group contains an iron ion + can bind to 1 molecule of O2. each Hb can hold 4 O2
Blood types
Blood also has antigens (little sugars + proteins) that mark blood cells as a type 1. TYPE A - A antigen, B antibodies2. TYPE B - B antigen, A antibodies3. TYPE AB- A + B antigen, no antibodies4. TYPE O - neither antigen, A + B antibodies Rh factor: blood surface protein RH+: RH antigen, no antibodies RH-: N/A, RH antibodiesO-: universal donor AB+: universal acceptormixing of different blood types results in: erythrocytes agglutinating (clumping together)
Fetal circulation
1. umbilical vein carries oxygenated blood from the placenta through umbilical cord to fetus 2. blood from this vein enters the fetus + branches to liver but most of it enters3. ductus venous (another branch) shunts blood from placenta + allows oxygenated blood from umbilical vein to flow into inferior vena cava: this mixes with deoxygenated blood so the blood in IVC is slightly oxygenated 4. the slightly ox. blood travels directly from RA to LA through the foramen ovale, (hole) *bypasses pulmonary circuit5. LA contracts and sends slightly ox blood through mitral/bicuspid AV valve to LV 6. LV contracts, blood passes thru aortic semilunar valve + into the ascending aorta 7. some of this blood will flow into smaller arteries branching off the aortic arch to provide O2 to developing braindeox blood from SVC only partially mixes w slightly ox blood from IVC w/in RA. 1. unmixed deox from SVC exits from RA + into RV2. ductus arteriosus allows deox blood to exit pulmonary artery to descending aorta*skips arteries supplying blood to brain, preventing deox blood from going thereblood here is now very slightly ox bc it mixed w slightly ox blood that was unable to make it to arteries from aortic arch 3. this blood goes to rest of developing body tissues then thru umbilical arteries (lower pressure than pulmonary) to go to placenta (since arterioles + capillaries here have low resistance to blood flow) for gas exchange How does it bypass the lungs? Foramen ovale + ductus arteriosus. why? fetal lungs are filled with fluid: not much O2arterioles + capillaries of lungs very constricted: high resistance in the lungs + high pressure in pulmonary arteryplacenta: highly vascularized organ in uterus its arterial blood supply provides O2 + nutrients to fetus thru umbilical cord + removes waste allows for gas exchange to occur b/w maternal + fetal blood
Erythroblastosis fetalis
usually blood from mom + child doesn't mix across the placenta due to embryonic chorion * only occurs if mom is RH- and fetus is RH +1. RH + from fetus mixes with RH - from mom due to tear in embryonic chorion + placenta during labor 2. mother's B cells then produces anti-RH antibodies (if 1st pregnancy both will survive)3. if 2nd baby is RH +, anti-RH antibodies are small enough to cross embryonic chorion of placenta and will destroy fetal RBC: hemolysis causing the baby to be severe anemic (deficient in blood cells) the baby will have a difficult time transporting O2 to its tissues and may be swollen + pale
Lymphatic system
lymph: circulating fluid in lymphatic system: interstitial fluid, bacteria, fats + proteins lacteals (type of lymph. cap) absorb dietary fats from vili (small finger like projections that increase SA or absorption) in the small intestine lymph nodes: contains many lymphocytes + verifies if there is any harmful bacteria in the lymphlymphatic system has no central pump= low pressure system (similar to veins)skeletal muscle pumps + contractions of smooth muscle cells in vessel walls push lymph forward solute concentration in blood vessels heavily influences lymph volumecomposition changes bc of constant exchanges of substances b/w blood + IS fluid. increase of protein in blood vessels: water is drawn in to bloodstream, decreasing lymph volumedecrease of protein in blood vessels: water isn't pulled in as much, more water remains as IS, increasing lymph volume
lymphatic circulation
not all fluid at venous end of capillary is reabsorbed remaining fluid: interstitial fluid (b/w cells) is taken up by lymphatic capillaries as lymph* very leaky so osmotic pressure at venule end is enough to force fluid into them lymph capillaries merge together to from larger vessels that travel to by lymph nodes + go towards the heart lymphatic veins dump lymph into circulatory veins that connect to the heart (NO DIRECT CONNECTION TO HEART)Lymph from right upper torso: right lymphatic duct into the subclavian and jugular veins everywhere else: drains into thoracic duct and then the subclavian and jugular veins