1. 1 Circulation 11/11/2007

2. 2 Circulation  The circulatory system I.General plan II.Blood III.Heart 3

3. 3 Circulation  Movement of blood results from:  Force imparted from contractions of the heart  Elastic recoil of the arteries following filling by cardiac contraction  Squeezing of blood vessels during body movements  Peristaltic contractions of the smooth muscle surrounding the blood vessels 4

4. 4 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings A chamber pump ( with valves) : - Has a contractile wall,or - Compressed by around muscle this vessel has valves for unidirectional flow Heart types

5. 5 In human muscle to move blood against gravity

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7. 7 2- Peristaltic pump - Without valves - Ex, Insect

8. 8 Circulation I.General plan  Two main types of circulatory systems 1.Open circulatory system  Present in many invertebrates  Blood pumped by heart empties into a hemocoel  Hemolymph bathes tissues directly  Large volume (20-40% of body volume)  Low pressure (4.5-9.7 mm Hg)  Limited ability to alter velocity and distribution of blood flow 5

9. 9 Open Circulatory System Artery Veins There is no distinction between blood and interstitial fluid, collectively called hemolymph. Fig 42.2

10. 10 In insects, other arthropods, and most mollusks, blood bathes organs directly in an open circulatory system. One or more hearts pump the hemolymph into interconnected sinuses surrounding the organs, allowing exchange between hemolymph and body cells.

11. 11 In insects and other arthropods, the heart is an elongated dorsal tube. –When the heart contracts, it pumps hemolymph through vessels out into sinuses. –When the heart relaxes, it draws hemolymph into the circulatory through pores called ostia. –Body movements that squeeze the sinuses help circulate the hemolymph.

12. 12 Circulation 2.Closed circulatory system Vertebrates and some invertebrates (e.g. cephalopods) Blood flows in a continuous circuit Small volume (5-10% of body volume) High pressure (can attain pressures of > 100 mm Hg) Permits high O 2 uptake Allows for ultrafiltration at the kidneys 7

13. 13 Closed Circulatory System Interstitial Fluid: fluid directly bathing cells of the body – distinct from blood. Artery Veins Capillaries Blood Fig 42.2

14. 14 Circulation  Basic components of a closed circulatory system  A main propulsive organ (heart)- forces blood through the body  An arterial system- distributes blood and serves as a pressure reservoir  Capillaries- transfer of materials between blood and tissues  Venous system- returns blood to the heart and serves as a storage reservoir 8

15. 15 In a closed circulatory system, as found in earthworms, squid, octopuses, and vertebrates, blood is confined to vessels and is distinct from the interstitial fluid. –One or more hearts pump blood into large vessels that branch into smaller ones cursing through organs. –Materials are exchanged by diffusion between the blood and the interstitial fluid bathing the cells.

16. 16 Closed Circulatory System In a closed circulatory system –Blood is confined to vessels and is distinct from the interstitial fluid Figure 42.3b Interstitial fluid Heart Small branch vessels in each organ Dorsal vessel (main heart) Ventral vessels Auxiliary hearts (b) A closed circulatory system Closed systems are more efficient at transporting circulatory fluids to tissues and cells. Earthworm an annelid is the first time we see a closed circulatory system!

17. 17 Blood capacity The higher oxygen capacity of blood, the less volume needs to be pumped. See figure 3.25- p(122). Invertebrate 30% B.W Vertebrate 5-10% B.W Control by : PUMPING FREQUENCY STROK VOLUME

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19. 19 The body plan of a hydra and other cnidarians makes a circulatory system unnecessary. –A body wall only two cells thick encloses a central gastrovascular cavity that serves for both digestion and for diffusion of substances throughout the body. The fluid inside the cavity is continuous with the water outside through a single opening, the mouth. Thus, both the inner and outer tissue layers are bathed in fluid. Many invertebrates have a gastrovascular cavity (or) / a circulatory system for internal transport

20. 20 Phylum Cnidaria gastrovascular cavity is fluid filled and ciliated may branch into tentacles

21. 21 In cnidarians like Aurelia, the mouth leads to an elaborate gastrovascular cavity that has branches radiating to and from the circular canal. –The products of digestion in the gastrovascular cavity are directly available to the cells of the inner layer, and it is only a short distance to diffuse to the cells of the outer layer.

22. 22 Planarians and most other flatworms also have gastrovascular cavities that exchange materials with the environment through a single opening. –The flat shape of the body and the branching of the gastrovascular cavity throughout the animal ensure that are cells are bathed by a suitable medium and diffusion distances are short.

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24. 24 Annelid plan: Closed circulation Respiratory pigments ( HB, Chlorocurin,hemocyanin ) Earth worm : Highly vascularized surface. Two main blood vessel : Dorsal propel blood forward Ventral propel reverse

25. 25 Several blood vesel have dilations ( contractile) These connection blood vessels act as accessory heart

26. 26 - Annelids Figure 17.19 Mouth Brain Accessory hearts Main heart Coelom Nerve cord Digestive tract Blood vessels Segment walls Excretory organ Anus

27. 27 Giant earth worm Dorsal B.V contract ( peristaltic) 6-8/min BP= 20 mm.Hg Five pairs lateral hearts contract after dorsal to give 75mm.Hg Largest animal without respiratory system 120cm length, 2-3cm dim 500g wight its Hb po 2 50%= 7mm.Hg

28. 28 Echinoderms Star fish, sea urchins, sea cucumber … Has three fluid system : a- Coelomic, b- Hemal (blood), c- Water Coelomic between skin and digestive system For transport nutrients

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30. 30 water Vascular system In sea star From outside to madreporite to stone canal to ring canal to radial canal to ampulla to tube foot.

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36. 36 Have a water vascular system that facilitates gas exchange and waste disposal

37. 37 Sea cucumber have hb and high oxygen affinity PO50% = 5-10 mm.Hg( depend-T) Boher effect not exist between 7.5-6.6 Ph -,Not sensitive at this stage Because it’s mud is low O 2.

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39. 39 Mollusca Except: squid, and octopus - All mollusca have an open circulatory system -With hemocyanin or hemoglobin

40. 40 OPEN CIRCULATORY SYSTEM Mollusca Have well developed hearts, heart rat according to its need for oxygen. - Acetylcholine from nervous system to inhibit heart. - Serotonin excitatory

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42. 42 Movement: wavelike muscular contractions of the foot move gastropods smoothly over surfaces

43. 43 Blood act as hydraulic fluid of clams and snails By large blood sinus in foot Two-chambered heart of a mollusk Helix(snail) an open system

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45. 45 -Closed circulatory ( arteries and veins) -It might be related to respiratory gills and to Form a renal pressure 75mm.Hg. -Blood 6% separated about interstitial fluids15%. -Other mollusks ( open 50%) because mixed of both blood and fluid -Blood distributes according to O 2 consuming what about closed mollusks, cephalopods (octopus and squid)

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47. 47 Insects Blood vessel along dorsal side Posterior parts as heart and with valves opening Anterior part called aorta Contractile to propels blood forward Peristaltic wave

48. 48 Pulsating organ : accessory hearts in antenna, legs and wings Longitudinal membrane to diffusion of blood

49. 49 After aorta blood paths to other parts not by vessel. Low B.P no respiratory function. - Aliform muscle around the dorsal heart contract dorsal heart wider by suction will be filled

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51. 51 These are from groups of arthropods Arachnids, such as spiders, scorpions, ticks, and mites Arachnids Figure 17.22

52. 52 In many invertebrates ( open) Heart pumps blood into hemocoel – open fluid space- either called blastocoel The fluid in hemocoel called hemolymph or blood and reach tissue by bathing not by vessels

53. 53 Spider and scorpion -similar to insect but have respiratory role Hemocyanin in scorpion With respiratory organs ( lung books) Blood pressure --- hydraulic for foot expansion In jumping spider has BP=400mm.Hg

54. 54 Insect - scorpion

55. 55 Crustaceans, such as crabs, lobsters, crayfish, shrimps, and barnacles Figure 17.23 Crustaceans

56. 56 Open, and partially open circulatory system. The smallest one without developed circulation Lobster, crabs, Cray fish ------(decapods) Good circulation + respiratory pigment ( hemocyanin) Has gills Dorsal heart in pericardial sinus with ostia

57. 57 Crustacean circulation

58. 58 From heart : -Anterior aorta forward -Posterior aorta backside -To branches for tissues.

59. 59 Partially open system - Lobster Gill circuit is enclosed, Feeds hemolymph back to heart Heart pushes hemolymph out through anterior and posterior arteries Hemolymph flows into sinuses

60. 60 Heart O 2 blood to tissues Gills oxygenation While in fish heart receive deoxygenated blood and pumps it to gills then to tissues and reverse to heart.