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Some invertebrates have evolved specific transport systems. For example: Sponges- they circulate water from the external environment and that is through their bodies instead of circulating and internal of fluid Cnidarians such as with Hydra- they have also fluid field, internal gastrovascular cavity and this cavity would supply the nutrients for all body cells that are lining, the cavity. And this would also provide oxygen from the water and is the reservoir for carbon dioxide and other ways.

• they have simple body movement,that would move the fluid inside there, a cavity for rooms. Worms (Flatworms)- have gastrovascular, cavity such as in the case of planarians
• it's a more complex n as compared with the Hydra because it has a branch gastrovascular cavity that runs close to all body cells;spreads through the entire body cell of the planaria. So this would allow diffusion distances for both the nutrients, the gases and the wastes to be shorter as compared with the other two and the body movement of plenaria and would help this materials to be distributed in various parts of the body. One disadvantage though of the system of the planarian it is limited by its small size. tshape nt to maintain that a small diffusion at distances next.   Also in the case of our rotifers n and in or generally invertebrates that have pseudocyloon nw like the rotifers nematodes, they would use their ceramic fluid of their body cavity in order to transport. Nw there the nutrients inside there are cavity. So most of these animals are relatively small and the movements of the body against the syllomic fluid, which are indirect contact with the internal tissues. And the organs would produce that adequate transport.

● Echinderms-they would depend largely also in their body cavity as their salamic transport chamber. ● Molusk- the transport functions would occur in a separate circulatory system. So the circulatory or the cardivascular system. This is a specialized system in which there is a muscular pumping. Heart, that = move the fluid medium, in invertebrates, the common would be a hemolymph,or blood for about higher level of animals, and it would be moved in a specific direction that is determined by the presence of blood vessels. So in the animal kingdom, it has two basic types of circulatory system. We have the open a circulatory system, the you have the heart that would pump the hemolymph or the blood out into the body cavity or at least through parts of the body cavity. Whereas the hemolymph would be the cells, the tissues and the organs. So open there is n blood vessels in contrast to the closed circulatory system. The blood circulates in the confines of tubular vessels and the ceramic Fluid of some invertebrates also has a circulatory role either in concert with or instead of the hemolymph or the blood. ‘ ● Annelids such as earthworms - they have closed circulatory systems in which the blood would trave through the vessels, delivering nutrients to the cells and also for the removal of waste ● mollusks and arthropods - they have open a circulatory systems and which their hemolymph or their blood would directly base the cells and tissues, rather than being carried only in the vessels. So, for example, in an insect, in an insect heart, it would pump hemolymph through the vessels that would open into the body cavity and ● octopus and others cephalopods and mollusk annelids and also vertebrates, like, for example, this fish - it has a close circulatory system as well. we're in the walls of the heart and the blood vessels are continuously connected and the blood never leads the vessel. And you can see there, the black arrows would indicate the direction of the blood flow.

CHARACTERISTICS OF INVERTEBRATE COELEMIC FLUID,HEMOLYMP AND BLOOD CELLS ● Echinderms, Nematodes- they would use their coelomic fluid as the supplementary can also be as a supplementary, but really, it's theirsole circulatory system. So the coelomic fluid may be identical in composition whether interstitial fluids or it may also differ, particularly with respect to a specific proteins or cells, but the main function of it is for transportation of gases nutrients and ways products, and it may also function in certain invertebrates like, for example, in nematodes as their hydrostatic skeleton. So, if you could still recall our discussion with skeletal system, nw there's coelamic fluid. Basically a place a vita lrole in their movement. Nw, as their hydrostatic skeleton, the hemolymph, is the circulating fluid of animals with an open circulatory system. So most are arthtropods and ascidians have this hemolymph.So in this animals, there's a heart that would pump this hemolymph. Low pressures through vessels to tissues spaces and generally, the hemolymph volume is high and the circulation is slow. So in the process of movement, the essential gases and nutrients and wastes are being transported. So there are many times were in hemolymphs and has a nn-circulatory function. So it could also play a role in for example, in moulting of the old cuticle and insects and also in the inflation of their wings and also in certain jumping spiders, the hemmolymp would also play a role as a source of hydrostatic pressure that would provide the jumping spiders there, hydraulic mechanism for limb exension.The we have the blood cells nt or Hemacythes these are basically the circulating cells. So some cells would contain a respiratory pigment such as your hemoglobin and basically called your erythrocytes or red blood cells and these cells are usually present in high numbers to facilitate the oxygen transport. There are also cells that do nt contain respiratory pigments and may have other functions, like, for example, for blood, clotting, and the number and types of blood vessels would vary dramatically in different invertebrates For example, in annelid, blood,They have hemocythes that are phagocytic. And then the coelamic flid may also contain in blood example in celiomocytes,lymphocytes and phagocytes. And so on this would mean, if function in phagocytosis glycogen storage encapsulation of Defense responses, and also for excretion, and then, in the case of mollusks they have two general types of hemocytess, like the amoebocytes and granulocytes These are basically have a function for Pearl, formational in mollusks and in some bivalves for insects, they would also have hemolymph that would contain large numbers of various hemocythes that would function also for clotting for phagocytosis. So those are the different invertebrates coelemc fluid,hemolymph and blood cells

TRASPORT SYSTEM IN INVERTEBRATES all vertebrates have a close a circulatory system in which the walls of the heart and the blood vessels are continuously contracted and the blood never leaves the blood vessels. So the blood would move from the heart, through the arteries, arterials, capillaries venules veins, and back to the heart and exchange between the blood and the extracellular fluid. That would only occur at Capillary level.

CHARACTERISTIC OF VERTEBRATE BLOOD AND BLOOD CELLS So overall vertebrate blood would transport oxygen carbon dioxide and nutrients and would defend against harmful microorganisms cells and viruses. It would also function to prevent blood loss through coagulation or clotting and would also help in the regulation of body temperature. And so, because it's a liquid, the vertebrate blood is classified as a specialized type of connective tissues. The blood is part of the connective tissue category. So the blood would contain a fluid Matrix knw which we term as plasma and different cellular Elements which we call as formed elements.

The cellular components of the vertebrate blood. So the process of blood cell production is termed as hematopoiesis. So, you can ntice that all blood cells, begin their lives in the bone marro within the vertebrates body, and then it has different precursors. S the erythrocyte, precursor the leukocyte and the Megakaryocytes. The leukocytes would would be dictated by the thymus grand in order to form the agranulocytes and the counterpart of that. The other type is granulocytes, the abdrine.Nw the agranuocytes would form the moncytes and the lymphocytes. The moncytes would form your macrophages, lymphocytes would form the B cells and T cells whereas your granulocytes would form esnhls,basophils and neurophils. And the erythrocyte precursors would form your erythrocytes and then your mega carriosides would form your platelets.

BLOOD COMPOSITION The blood is made up of plasma and formed elements.The plasma is basically the straw colored liquid part of the blood. So in mammals plasma is about a 90% of water and would provide the solvent for dissolving and transporting nutrients. So there's a group of proteins that can be found on the plasma, that would be the albumian fibringen and the globulins. So it would comprise a portion, of the plasma that's basically seven percent. The concentration of this plasma proteins would influence the distribution of water between the blood and the extracellular fluid. So, because the albumin, you can ntice that there on the figure on your screen that it represents about 60% nw of the total plasma protein. So it plays an important role with respect to water movement, whereas the fibringen is necessary for a blood coagulation or the plotting, and then you have the globulins which include immunglobulins and various metal binding proteins. The remaining 3% of the plasma is composed of their electrolytes, amin acids glucose and other nutrients, various enzymes hormones, metabolic waste, and traces of many inrganic and organic molecules. The other composition of blood would be the platelets or the scientific term, the technical term for that, would be thrombocytes.the platelets are so named because of their plate like flatness or thrombocytes from the Greek from thrombust meaning clot cells. So this are the disk shape cell fragments that would initiate blood clotting. So for example, when a blood vessel is injured, the platelets would immediately move to the side and clamp n attaching themselves to the damage area and thereby beginning the process of blood coagulation. We also have a part of the blood would be your white blood cells or WBC, or the technical term for that would be the leukocytes coming from the Greek term lucos. Meaning whitet cells knw this are scavengers that would destroy microorganisms at infection sites and would remove foreign chemicals and remove the debris and that would result from dead or injured cells. So, all of our WBCs are derived from immature cells in the bone marrow. Among the granular sites. There are two types of or two groups or categories of your WBCs. the granular sites, which would include your eosinphils ,this our phagocytic and would ingest foreign proteins and immune complexes. In mammals the eosinphils would also release a chemicals that would counteract, the effects of certain inflammatory chemicals that are released during our allergic reactions.Basophils are the least numerous white blood cells. So when they react with foreign substance their granules would release histamine and heparin. Histamine,this causes the blood vessels to dilate and leak through with, at the site of inflammation, whereas the heparin would prevent blood clotting, The other granulocyte would be the neutrophils, this are the most numerous of the white blood cells and they are kept regularly attracted to the sides of inflammation and their active phagocytes. The other category of white blood cell would be your agranulocyte. We have two types, the moncytes, and the lymphocytes. moncytes,there are critical components of innate immune system. There are the source of many other vital elements of the immune system, like for example, your macrophages and it plays a role in both the inflammatory and anti-inflammatory processes that take place during immune are response the lymphocytes. So we have two types. the B and the T cells knw, both of which are central to the immune response. B cells, would originate from the bone marrow and would colonize the lymphoid tissue where they mature in contrast, T cells are associated with it and influence by the thymus gland, before they colonize the lymphoid tissue and they be activated. rather than when b cells are activated, They divide and differentiate in order to produce plasma cells and this cells are responsible for antibody production and direct cell mediated killing of virus, infected and tumor cells and of course, the regulation of the immune are response. So basically, the difference of the granulocythes,this are mainly involved in the innate immunity producing and immune response which is nn-specific to a particular pathogen. Agranulocytes this are. Mainly involved in the adaptive, adaptive immunity and it could produce an immune response which is specific to a particular pathogen. And then, of course, nw we have the other. the last composition of the blood, which is your blood cells, red blood cells, our technical term for that, would be your erythrocytes, they would actually vary dramatically in terms of size, shape and number indifferent vertebrates. So for example, the RBCs of most vertebrates are nucleated meaning it has nucleus but the mammalian RBCs, it's inculated meaning, it doesn't have a nucleus, there are some fishes and amphibians. So also have inculated red blood cells and among all vertebrates, the salamander and puma,It, which has the large just red blood cell. the avian RBCs, this are oval shape and located, and larger than the mammalian RBCs, and among the birds,itt's the ostrich would have the largest RBC. Most mammalin RBCs are biconcave disk, however, in contrast would camels, and Lama knw they have elliptical RBCs. So the shape of the biconcave disk provide a larger surface area for gas you Sean as compared with a flat desk or a spear. So generally the lower vertebrates would tend to have fewer but larger RBCs than the higher in vertebrates. Almost entire a mass of an RBC would consist of the hemoglobin,the hemoglobin is and iron containing protein. So, it's a type of protein and it's major function is to It's major function is to pick up oxygen from the environment and the oxygen would bind to the hemoglobin in order to form the oxyhemoglobin and it would transport to the body tissues. So the blood rich and oxyhemoglobin is bright red in color and acts as the oxygen diffuses to the tissues, the blood becomes darker and appears blue when observed through the blood vessel walls. However when this a less oxygenated blood is exposed to oxygen. For example, when a vein is caught and a mammal begins to bleed, it instantaneously, turns bright red and the hemoglobin also carries nt just the oxygen, but also the waste gases, like your carbon dioxide from the tissues to the lungs for removal from the body through exhalation.

And then nw we have also differences in the blood different blood vessels nw, so we have the arteries veins and the capillaries. So the arteries are elastic blood vessels. That would carry blood away from the heart to the organs and tissues of the body. So, the central canal, as you can ntice of the artery, is a lumen and just like of all the rest of the vessels, lumen is the central canal and surrounding the lumen of an artery is a thick wall that is composed of three layers.The inner middle and the outer layer. Veins are relatively inelastic, large blood vessels, that would carry blood from the body tissues to the heart. artery would carry blood from the heart to the organs.Veins would carry blood from the body to the heart. N. So the, the wall of the vein would contain the same three layers just like of the artery But the middle layer is much thinner And one or more valves, is a present. So the valves basically, the present to our veins would permit, the blood flow in only one direction, which is important in returning, the blood to the heart. Capillaries the smaller arteries which is term as arterioles would branch to form capillaries, which is connected to the smaller veins which we call as venules. So capillaries are generally composed of a single layer of endotelial cells and these are the most numerous blood vessels in the animals body. So the abundance of capillaries makes an enrmous a surface area available, for the exchange of gases of fluids ,nutrients and waste between the blood and the nearby cells.

2.THE HEART AND THE CIRCULATORY SYSTEM The heart and the blood vessels have actually changed greatly as vertebrates move from water to land as endothermia evolved and examples of these trends, So this are the phylogenetic trends in the circulatory system of animals that there is an increase complexity in the of the circulatory system, which would reflect daptations of different environments. On the lower formsfrom polyphera to the nematodes, basically, diffusional mode, and then you have the open and closed circulatory system and then from the tunicates, the heart, which started, as for officious two, chambered three chambered reptiles and amphibians, and then four chambered for mammals birds, and crocodilians. There's an increasing complexity of the circulatory systems .This is the figure is the heart and circulatory system of bony fishes So the bony fish heart has two pumping chambers. The atrium and the ventricle.. So when the ventricle pumps, the blood would leave the heart by the ventral aorta, which goes to the gills and in the gills the blood becomes oxygenated and would lose the carbon dioxide and would enter the dorsal aorta. So the dorsal aorta would be the one to distribute the blood to all of the body organs. And then the blood would return to the heart via the venus system so because the blood only passes through the heart once; it is called single circulation circuit. So this kind of circuit has an advantag of circulating oxygenated blood from the gills to the systemic called capillaries in all organs, almost simultaneously. However, the circulation of blood through the gill, capillaries offers resistance to flow, and the blood pressure and rates of flow, to the other organs, are those appreciably reduced and this kind of arrangement probably could nt support high metabolic rate that are already present in most birds and mammals.

So the movement of the fish, the angelating a movement of a fish body would help to move the blood back to the heart. In amphibians and reptiles though they have the evolution of double circulatory circuit in which the blood would pass through the heart twice and during its circuit the through the body, it has overcome the slow blood flow, a problem, which was present in the bony fishes. So, amphibians knwing that the amphibians were the first vertebrates, to invade the land and some of the reptiles were example with alligators and crocodiles. They have already a four chambered heart but as you can ntice here, there hearts are nt fully divided into two so there is n division between thebetween the chambers of the heart. So in amphibians there's a single ventricle That would pump a blood of both in to the lungs and to the rest of the body However, because most amphibians who absorb oxygen and through their skin.For example, in toad's or in frogs a blood returning from the skin. Also contributes nt to the oxygenated blood to the ventricle and then the blood pumped out to the rest of the body is therefore, highly oxygenated, in the case of a reptiles the ventricle,it's partially divided into right and left side so the oxygenated blood from the lungs would returned to the left side of the heart via the pulmonary vein and does nt mix match with the oxygenated blood in the right side of the heart. So when the ventricles would contract, the bloody is pump into the aorta. For distribution throughout the body as well as with the lungs. So this kind of incomplete. Separation of the ventricles is actually important, to adaptation for reptiles, such as, for example, turtles because it allows blood to be diverted away from the pulmonary circulation during diving or when the turtle is withdrawn into its shell. So this would conserve them energy and would divert blood to the vital organs during the time. When the lungs cannt be ventilated.even though the official logical separation divide is almost complete in most reptiles the complete anatomical separation of ventricles, occurs only in the crocodilians and the dinsaurs and birds and of course in mammals. And this lineage complete a separate creation anatomical Separation of the ventricles. So this evolves separately in the two lineages which is a testament to the importance of its functional and active and mostly endothermic animals. So here the heart and the circulatory systems of various vertebrates where in the oxygenated blood, is r red.and the less oxygenated blood is Nw blue. The bony fises has a heart that has two chambers, only the atrium and the ventricle and would pump in series the respiratory, and systemic circulations are nt separated . for the amphibian, the amphibian heart has two, atria, they have their left and the right and the blood from the lungs would enter the left atrium so it's in the left atrium that the oxygenated would enter and the blood from the body would enter the right atrium. So from the lungs, it would enter the left and then from the body it would enter on the right. So they both from atria empty, into one of ventricle, which then pumps into the respiratory and into the systemic circulation. And then in most reptiles, this exhibit, a great, third degree of anatomical division of the ventricle into two halves but it is in the crocodilians in birds and mammals the ventricle has been completely divided. Forming the four chambered heart, with a blood flow through the lungs that are completely separated from the flow to other tissues. the black arrows points into the direction of the blood flow.

So, looking closer to the circulation of the blood in birds crocodilians and mammals. So, the blood circulates throughout the avian, and the crocodilian and mammalian a bodies into two main circuits,, the pulmonary circulation and the systemic circulation. So you can see here, there's an upper and there's a lower systemic circulation. So the pulmonary circuit or pulmonary circulation supplies, the blood into the lungs, only rather only to the lungs and it carry the oxygen poor blood from the heartthe blue one to the lungs, where carbon dioxide is removed and the oxygen is added. And then it returns, n, it returns the oxygen, rich blood to the heart for distribution to the body. The systemic circulation may be upper or lowe would supply the cells, the tissues and the organs of the body with oxygen rich blood and would return, the oxygen poor blood to the heart. So that's basically the differences between pulmonary and the systemic circulation.

the Mamalloan heart is a hard working pump that would move blood through the body. So the heart of an average human would be around 70 times per minute, and that's more than 100,000 times per day., so in a, for example, if you're in a 70 year lifetime, the heart would beat more than 2.6 billion times n. And the heart rate of other vertebrates, would actually vary, with respect to their body sizes and metabolic rates. The relationship between the heart rate and the body weight. So in general, small animals, have higher heart rate than tthe larger animals. So this is basically due to the higher metabolic rate due to a decrease in body size. So for example, elephant has a heart rate of about 30 beats per minute As in comparison with a cat with a heart 130 beats per minute and then a rat which would have 420 beats per minute and the tiny shrew, the smallest mammal which would have 835 a bit per minute.

to study the morphology, you knw, of a mammalian, heart in detail, there's n more appropriate example than the human heart So the, the heart of other mammals and birds are basically similar to uans.The human heart will the example. So, most of the heart is composed of the the cardiac muscle tissue, which we term as myocardium.the outer protective covering of the heart, however, is five rows connective tissue, which is what we term as the epic cardio, the connective tissue, and the endothelium form the inside of the heart, or the endocardium, and the left, and right halves of the heart are two separate pumps. Each containing a two chambers and in each half the blood of first flow ad a thinned walled atriumand to a thick walled ventricle and they're also valves in between the upper and the lower atria and the ventricle chambers.the tricupid valve has evolved is between the right atrium and the right ventricle and then you have the the bicuspid valve in between theleft atrium and the left ventricle. So this two are collectively termed as your atrioventricular valves or AV valves and then the pulmonary semilunar valve is at the exit of the right ventricle and the and then the aortic semilunar valve,The exit going in into the aorta so that two is collectively termed as semi lunar valves. So all of this valves would open and close due to blood pressure changes when the heart contracts during each heartbeat and like the valves in the veins, heart. Valves also, keep the blood moving and one direction preventing the black flow

the pathway of the blood in our heart so the okay the deoxygenated red blood cells,from the various parts of the body would enter the right atrium. Would pass through the trike speed valve and then continue to the right of ventricle. And then going into the lungs through the left and right pulmonary artery. And then from the lungs, iit would be oxygenated and would enter the left and right. pulmonary veins going in to the left atrium and then passing through the bicuspid, or the mitra valve and then the left ventricle and then would pass through the aortic semilunar valve and going into the aorta and to the rest of the body. And then the cycle continues. So that's basically the pathway of blood particuarly for human.

If you lined up all the blood vessels in your body, they be 95,000 kilometers long and every day they carry the equivalent of over 7,500 liters of blood though, that's actually the same for or five liter recycled over and over delivering oxygen and precious nutrients like glucose and amin acids to the body's tissues. All that blood exerts, a force on the muscular walls of the blood vessels. That force is called blood pressure and it rises and falls with the phases of the heartbeat. It's highest during systemally when the heart contracts to force blood through the arteries. This is your systolic blood pressure. When the heart is at rest between beats blood pressure, falls to lowest value, the diastolic, pressure A typical healthy individual produces, a systolic pressure between 90 and 120 millimeters of mercury and diastolic pressure between 60 and 80 Take in together. A nrmal reading is a bit less than 120 over 80 The blood traverses the landscape of the body through the pipes of the circulatory system In any plumbing system, several things can increase the force on the walls of the types. The properties of the fluid extra fluid or narrower pipes, So it's the blood thickens. A higher pressure is needed to push it. So the heart will pump harder. Salt diet will lead to a similar result. The salt promotes water retention, and the extra fluid increases, the blood volume and blood pressure and stress like the fight, or flight response. Releases hormones, like epinephrine, and nrepinephrine that can strict key vessels increasing the resistance to flow and raising the pressure Upstream. Blood vessels can usually handle these fluctuations easily and elastic fibers embedded in their walls, make them resilient. But if your blood pressure regularly rises above about 140 over, 90 what we call hypertension and stays there, It can cause serious problems. That's because the extra strain on the arterial wall can produce small tears, when the injured tissue swells up, substances that respond to the inflammation like white blood cells, collect around the tears Fat and cholesterol floating in the blood latch onto Eventually. Stiffens and thickens. The inner arterial wall, This condition is called atherosclerosis and it can have dangerous consequences. If the plaque ruptures a blood clot forms on top of the tear clogging, the already narrowed pipe. If the clot is big enugh, it can completely block the flow of oxygen and nutrients to cells downstream In vessels that feed the heart that will cause a heart attack. When oxygen deprived cardiac muscle cells start to die. If the clock cuts off blood, float to the brain. It causes a stroke Dangerously clogged blood vessels. Can be widened by a procedure called an angioplasty There. Doctors thread a wire through the vessel to the obstructed site and then pass a deflated balloon. Catheter over the wire When the balloon is inflated. It forces, the passageway open again Sometimes a rigid tube called a stent. Is placed in the vessel to help. Hold it. Open letting the blood flow freely to replenish the oxygen starved cells downstream Staying flexible under pressure is a tough job for arteries the fluid. They pump is composed of substances that can get clogged them and your typical healthy hard beats that adds and at least two and a half billion times during an average lifetime, that may sound like an insurmountable amount of pressure, but don't worry. Your arteries are well suited for the challenge.

3.THE LYMPHATIC SYSTEM So the vertebrate lymphatic system begins with small vessels called the lymphatic capillaries. So you can see here on your screens right nw on the figure. This are in the right contact with the extracellular Fluids surrounding. The tissues.So this the system nw, the lymphatic systems one that is to collect in most of the fluid that sips from the bloodstream and accumulates in the extracellular fluids Second. That is to return small amounts of proteins that have left the cells. Third, to transport lipids that have been absorbed from the small in the spine and fourth to transport foreign particles and cellular debris to disposal centers which we call the lymph ndes. So the small lymphatic, capillaries would merge to form larger Lymphatic vessels, which we call the lymphatics. Lymphatics are thin walled vessels with valves, to ensure the one-way flow of lymph. Lymp, is your extracellular fluid that accumulates in the left vessel. So in the left vessel and the major lymphatic vessel would empty limp back into the venus circulation so you can see it here So this vessels would pass through the lymph ndes on their way back to the heart, for example,. So the lymph ndes this are your would concentrate and several areas of the body and this would play a vital role in the body's defense against a diseases. So the movement of lymph and mammals is accomplished by skeletal muscles squeezing against the lymphatic vessel. And in some cases, the lymphatic vessels would also contract rhythmiically and in fishes, for example, of all amphibian , and reptiles of birds embryos, and some adult birds, the movement of lymph is propelled by their lymph hearts nw and other parts. So you can see here a table, n showing the major structural components of the lymphatic system in the vertebrates. So in addition to those the lymphatic system of birds and mammals would also contain lymphoid organs such as the spleen, which would filter foreign substances from the blood and would Manufacture, the phagocycotic rather lymphocytes and then you also have the Bursa of fabricius in birds or the thymus gland iin mammals. And also others would be tonsils in mammals as well. So you can see here the summary of the major components of the lymphatic system which is vital to animals defends against injury and attack. For gas exchange so to take advantage of the rich source of It has simple, diffusion across a plasma membrane. You have the trachea the cutaneous exchange through an integument or body surface gain kills and then finally the locks. So in single cell rotates such as their protozoa, the diffusion across the plasma membrane, n, would move a gases into and out of the organism. Other multicellular invertebrates have either very plot bodies. Like for example, the flat worms in which all body cells are relatively close to the body sort surface or have bodies that are thin walled or in the case of hydra n hollow young body smell. So again gases would diffuse into and out of this animal. So, this is our first respiratory this, n, which is a diffusion through our body surfaces, in the case of protozoans, Nidorans and flatworms other terrestrial vertebrates. Like, for example, insects centipedes might sticks and spiders, they have tracheal systems consisting of highly branch kiting line, tubes, called the trachea nw. Also they have this trick here. Okay, from here. You can see if they're the longitudinal trickle trunk. So the trachea would open to the outside. N, of the body through a spiracles. N. And which usually have some kind of closure device to prevent excessive water loss. So the sparkles would lead to Drake gold trunks, that would eventually give rise to smaller branches, which we term as tracheal. So this one dog, who is blind ends with like close to all cells of the body and because there are n cells that are more than 2 or 3 µm from a Little gases would move with between the tracheal and the tissues of the body also through diffusion. So, most insects have this ventilating mechanism that would move air into and out of the trachea. For example, in contracting, a flight muscles of insects that would alternately compress and

Their large trick your Trunks and thereby Bentley the trachea. For invertebrates other invertebrates. Like, for example, earthworms nw that would live in moist environment, they use their integumentary system, nt for gas exchange, so earthworms have this capillary networks knw that, just a lie under their integument, which are used to for exchange of gases with the air spaces among the Soil particles.

Other Aquatic invertebrates would be very odd gases gas exchange with gills. Nw, also the simplest gills are small scattered projections of the skin such as in the dermal, brain, Kia of sea stars. So yeah, we came here nw their gills, the tiny projections, other Aquatic invertebrates have gas exchange structures and more restricted areas. For example, marine and annelid worms. They have this. Lateral projections called the paraphobia. N, that are richly supplied with blood vessels and would also function as gills for crustaceans and mollusks. Nw, for your stations,

Breaker stations and mollusks. They have guilts also that are compact and protected by a hardcovering devices. You can see it here gills. N and such skills would divide into highly branched structures to maximize. Nw, the area for gas exchange

For erect needs the man. They possess trachea of book longs or both. So the one that you can see on your screen is a book long. N, that are this are your paired imagination's. N of the ventral body wall that are folded into series of leaf like laminate. N. So the air would enter the bowl. The clong through this slit like opening n cold the spiral and would circulate in the lamellae. So respiratory gases would diffuse between the hemolymph moving along the lamely and the air in the air at chamber. So some ventilation also results from contraction of muscle attached to the doors outside of the air chamber. And this contraction would dilate the air, check the chamber and opens the spiral. But most gases would still be by diffusion. And then we have the pulmonite lung, the only major group of the restrail invertebrates whose members have a distinct air breathing structures would be the most scan. Nw, pop a sub glass full monata and that's basically your land snails and a slugs. N. So they have gas exchange structure. We they have this pulmonite long nw that opens to the outside by a poor called, the numerous dome. Okay. This one, the lumos tom. So this long is the drive from a feature common tamales in general. So you have their, the mental cavity, n, which in other mollusks would house the gills and other organs and some of the more primitive, pulmonite, a snails there are aquatic or freshwater there, and they would close the numerous storm dur submergence. So when the snail surfaces to breathe air, the new most stove would open so, but most of the higher pulmonates, they are terrestrial. So they would just rely on their lungs for their gas exchange. And the long may be ventilated by arcing and then flattening the body. But most gas exchange would still afford by a diffusion through the numerous dome, which is open. Most of the time or vertebrates naman. So including your aquatic vertebrates, like, for fish, amphibians, and some reptiles, they would rely on one or combination. N. Of the different surface tests for gas exchange rates getting his body, their external gels or internal gills. And with disability of the organism to exchange. Respiratory gases simultaneously with both air and water so a biodoodle organism for example, some salamanders crabs barnacles of bivalos and fishes like lung fishes. They would use their gills for water, breathing, and then lungs for air breathing. However, some gas exchange is always keeping use and some bimodal breeders to actually are actually considered to be tri model because they can use their skin. They can use their gills and they have long spa. So by model breathing, it was actually an important respiratory adaptation.

9:20 AM And that made possible the evolutionary transition, n between aquatic and terrestrial habitats. So Will talk about nw the vertebrate surfaces and the transitions nw. So let's start with the kitanus exchange. N. So some vertebrates have longs or gills and some have such as some aquatic turtle salamanders with longs, and then you have snakes specials and mammals that would use containers are respiration or integumentary exchange to supplement, gas exchange. However, kidneys exchanges mostly highly developed in frogs toads, long less, salamanders, and also newts. So, we knw that the amphibian skin has the simplest structure of all the vertebrate respiratory organs. So in frogs a uniform, capillary network would lie in a plane directly beneath their epidermis. And this vascular arrangement facilitates gas exchange between the capillary environment by both diffusion nw and convection and their slimy mucous layer. That keeps the amphibian skin, a moist and protects against injury. Would aid in this gas exchange. Some amphibians would obtain about 25% or more of their oxygen by this kidaneous exchange and the long list salamanders would carry out all of their gas exchange through their skin region. Next four. Guilt salon girls are your respiratory organs that have either 18, moist avascularized layer of epidermis to permit. A gas exchange across the teengill, a membranes, or a very thin layer of epidermis over highly vascularized undermiss. So the larval forms of few, fishes and amphibians have external gills. So, just like, what you can see here on axolotl, whereas you, I don't fish us that then have internal nw, internal gills. So you can see here if you try to remove the operculum, n, you would be able to see the gills inside. So, the gas exchange across, internal gills surfaces is extremely efficient, so it occurs as a blood and water would move on opposite direction so you can see it here. N, and opposite. And direction you movement on other side of the lamellar, epithelium, and each side of the head has four gill arches. Nw, these are your gill arch nw and each arch would consist of many filaments and this filaments, this one. N, this filaments would have the capillaries. Nw you can see it here, the capillaries within the lamely and you would nte that there is an the direction of the water flow. N, is a countercurrent. N, with the flow of the blood circulation. And this countercurrent flow would allow the fish to extract. The maximum amount of oxygen from the water and then, of course, the lungs. Nw also the lungs is an internal sac shade respiratory, organ. Okay. The typical long of a terrestrial vertebrate would comprise one or more internal of blind pouches into which air is either drawn. Of course, so the restaurant epithelium of long, sustain, a well-usularized. So you can see it here for mammals. N, it's a well vascularized and divided into large number of small units, which greatly increase the surface area for gaseous exchange. So you can see here the comparison on your screen right nw. The different lungs are the evolution of vertebrate longs showing the increased surface area. So from the amphibians, from the reptiles to the birds and to the mammals. So the this evolution of this would actually allow n, would actually allow the different organisms to perform this, their different public rates, according to their activity, as well, as their body size. Let's focus. Nw on the Uline, our respite authority, assist them. So the figure that you can see on your screen and you have the animation there nw That, that the values and of the human respiratory system. The air nrmally entered lives. This is stem through either and the oral cavity, you knw, it is cavities air would move to the banks, which is the common area. Yeah, for both agriculture. And then from the fairings it is connected to the larynx or the voice box and catamia is the esophagus, which would lead to the stomach. And then in and Larry and everybody's with a flap of artillage. This one n that would allow the air, the trick here in Halloween to perfect food or water around a trachea or the windpipe. And this branches out into the right and a left a broncos which would enter the lungs. N, and it branches into even smaller tubes, which we call as bronchials. And finally, the smallest the terminal, which are part of gas exchange of the respiratory system. So during a gasket exponent. So you can see here, nt alveolar, docks that are connected, connected to the respiratory bronchials and to a great like outpouchings, which we serve as alveoli, n or alveolus, the singular, the alveoli cluster would form an alveolar, sock and surrounding nw surrounding the algular, alveoli would be many capillaries. So if you lie, there's our functional units of the lungs and this is where the gas exchange would happen. It's basically through passive. Diffusion that is driven by a partial pressure gradient. So it would move oxygen from the alveoli into the blood and moves, the carbon dioxide from the blood into the alveoli and collectively, the alveoli would provide a large surface area for gas exchange. So if the alveolar epithelium of a human was removed from the lungs and put into a single layer of cells, they say the cells would actually cover the area of a tennis court. So we cannt surface area. So to, for you, to be able to visualize how ventilation, or basically breathing, n, or protecting filter is full moonary ventilation. It's good. See your inhaler and social care. So this different air movements would result from the rhythmic increases and decreases in the thoracic cavity volume. So for you to be able to visualize all the mechanism of how it works. Let us watch this a short clip.

Pulmonary ventilation is the inhalation and exhalation of air, this movement of air is caused by muscles of respiration and differences in air pressure between the atmosphere and the lungs. How does this work? Remember how gases move from an area of high pressure to low pressure? During inhalation air pressure in the app atmosphere is higher than in the lungs. So, air flows into the lungs, Conversely, during exhalation air pressure, in the lungs is higher than in the atmosphere. So air flows out of the lungs. How are these pressure differences achieved? According to boils law, increasing the volume of the lungs will decrease, the air pressure within the lungs During inhalation belongs. Expand pressure in the lungs drops compared to atmospheric pressure and air flows in This is achieved by contracting the muscles of inhalation. These include the diaphragm which increases the vertical diameter of the thoracic cavity, pulling the lungs down and the external intercostal muscles, which elevate the ribs, thereby increasing the anteroposterior and lateral dimensions of the thoracic cavity, Conversely, decreasing the volume of the lungs will increase the air pressure in the lungs and air flows out During exolation the lungs revert. Back to their original size, pressure in the lungs, rises compared to atmospheric pressure, and air moves out. This deflation of lungs is due to relaxation of the muscles of inhalation and bring quietessive process results from the elastic recoil of the lungs and the inward pull of surface tension. Exhalation can also become an active process During forceful breathing, for example, when exercising the abdominal and internal intercostal muscles contract, As they contract, they decrease the volume of the abdominal region and thoracic cavity, which increases the pressure in the lungs causing air to flow out faster. These differences in air pressure provide the primary force for road during pulmonary ventilation, right? So that's basically, you knw, the mechanism of how the inhalation, or, and exhalation or what we term, as the full binary of ventilation. So the air movements would actually result from the rhythmic increases and decreases in the thoracic cavity volume. And this changes in the volume would lead to reversals. Nw, in the pressure gradient between the lungs and the atmosphere and that is where the gases nw would follow such a great gent. So that's basically it for our lesson. Nw we have talked about the different transport systems. Nw the invertebrates that to basic types of circulatory system, the opening and close the open systems, generally circulate have a lamp and then the closest stems would generally circulate blood. And then for vertebrates, they use blood vessels and blood for the transport of gases and nutrients and waste. N, and the blood is a type of connective tissue that is made up of red blood cells. The white blood cells plasma and the platelets. We have also talked about the hearts and the circulatory systems like for example, in bony fishes, amphibians and reptiles the heart and the blood vessels would change a greatly as the vertebrates move from water to land, and as the end of the removal for birds, a crocodilians and malls. So, even though the logical separation of the blood in the left and the right right? Ventricles is almost complete and reptiles the complete and a comical, separation of ventricles have occurred only in the crocodilians in the birds and mammals and that the mammalian heart of pumps blah through the series of vessels. And from the arteries, the arterials of capillaries, the venials, the veins and back to the heart and the action of the heart consists of your cyclic contraction, the system and the relaxation or the diastole. So this contraction the systolic contraction generates blood pressure that forces blood through the closed system of vessels. We have also talked about briefly the lymphatic system, which is the open one way system that consists of one-way vessels nw that help return fluids and proteins to the circulatory system. And then we have talked about also, the gas exchange, n, other animals. That would respire aerobically, would need a con apply of oxygen and the process of acquiring oxygen and eliminating carbon dioxide is what we term as external respiration and that the exchange of carbon dioxide and oxygen across, I would occur across respiratory surfaces. So we have talked about jails, the cutaneous surfaces and the lungs and then of course invertebrate respiratory system. The air conducting portion of the respiratory system of air breathing vertebrates would move air into or the inhalation and out or the exhalation out of that system. So we call that process of air movement as that ventilation.

9:35 AM And then finally we have talked about the human respiratory system. The structure. And Extraordinary respiration in. Humans are typical n of a mammal. So the oxygen and carbon dioxide diffuse from areas of higher concentration to areas of lower concentration. And once in the blood, the oxygen diffuses into the red blood cells and binds into the hemoglobin for transport to tissues and the carbon dioxide in return are transported bound also to the hemoglobin as well as in the form of other ions and acids. So that's basically it for our lesson, 9 on circulation and guess exchange.

All right, so we have 10 minutes to spare for a questions or clarifications regarding the lesson.

You have any questions or clarifications regarding lesson 9, or probably your activity? There are synchronus activity. I hopefully send them. You would be able to, like knw, or for those who have tried already as an, a very beneficial, I believe. N, and my part, my perspective, when I assign that activity to you is, you would be able to visualize better, n, the circulation among the different. So please be able to perform and dedicate the required time. Nw, for you to be able to practice and visualize how circulation happens and or among different vertebrate organisms questions or clarifications

There.

Ashan Circle, guns, doing one leap, everything one's twice. Thank you either. Okay, thank you, Jerry Luu. Okay, see you. So if you have n more questions, I'll be uploading the lecture slides, as well as the recording once it becomes available. After the rendering nw of meet, then I'll update the post on our Google classroom. So see you take time to absorb, n and process. What you have just learned from our lesson for today and hopefully we'll be able to apply that. Nw once you continue answering your activity on a circulatory system, so thank you very much for joining me in this session. Happy lunch time advance, everyone and enjoy the rest of your day. You may knw stopping the call, but

Thinking.

Okay, boy. Nice all. Eat all. On.

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