Circulatory System Transport systems in animals Overview Functions

Circulatory System Transport systems in animals

Overview Functions of a transport/circulatory system Cellular transport Invertebrate circulation 1. 2. 3. a. b. c. d. Gastrovascular cavity Water vascular system Open circulatory system Closed circulatory system Vertebrate circulation 4. a. b. Fishes Amphibians c. d. e. Reptiles Birds Mammals

Functions of the circulatory system Transports materials Nutrients from digested food Respiratory gases: CO 2 and O 2 Waste materials: toxins and nitrogenous wastes Antibodies Hormones Enzymes Immune functions Maintains homeostasis Blood p. H Heat transport

Transport at the cellular level Cell membrane Passive transport (diffusion, facilitated diffusion, osmosis) Active transport spending energy moving materials from low concentration to high concentration of solutes Transport of large molecules high concentration of solutes to low concentration of solutes no need to expend energy endocytosis vesicles exocytosis Cyclosis (cytoplasmic streaming) occurs in eukaryotes, e. g. Paramecium facilitated by microfilaments requires energy

Transport at the cellular level (con’t) Endoplasmic reticulum Golgi apparatus manufacturing and transport facility proteins produced in rough ER are packaged in vesicles modification and storage facility receiving end and shipping end Vacuole large membrane bound sacs usually stores undigested nutrients

How are materials transported in multicellular organisms? Gastrovascular cavity in simple invertebrates No system is required Single opening: exchange of materials with the environment Central cavity for digestion and distribution of substances throughout the body Body walls are two cell layers thick materials undergo diffusion Cnidarians (e. g. Hydra) and flatworms (e. g. planarians)

How are materials transported in multicellular organisms? Water vascular system in echinoderms multi-purpose: locomotion, food and waste transport, respiration closed system of canals connecting tube feet madreporite ring canal radial and lateral canal tube feet ampullae

How are materials transported in multicellular organisms? Open circulatory system Phylum Arthropoda, Phylum Mollusca (with one exception) hemolymph (colorless) heart(s) sinuses ostia heart(s) diffusion from sinuses to organs insects: well-developed respiratory systems, O 2 not transported through the blood

How are materials transported in multicellular organisms? Closed circulatory system or cardiovascular system cephalopods, annelids, vertebrates presence of blood vessels advantages 1. rapid flow 2. may direct blood to specific tissues 3. blood cells and large molecules remain within vessels 4. can support higher levels of metabolic activity

General plan of the cardiovascular system Heart Blood vessels Atrium Ventricle Arteries Arterioles Capillaries and capillary beds Venules Veins Blood

Different adaptations of the cardiovascular systems in vertebrates: fishes Single-circulation Fish heart 2 chambered hearts atrium and ventricle vessel African lungfish heart 3 -chambered 2 atria left side of atrium receives oxygenated blood (to tissues) right side receives deoxygenated blood (to lung or gills) spiral fold partially divided ventricle

Different adaptations of the cardiovascular systems in vertebrates: amphibians Pulmocutaneous and systemic circulation are partly separated Amphibian heart 1 ventricle pumps blood to lungs, skin, and tissues 2 atria: rt. atrium receives deoxygenated blood lt. atrium receives oxygenated blood advantage: oxygenrich blood reaches the body’s organs faster some mixing of O 2 -rich and poor blood occurs

Different adaptations of the cardiovascular systems in vertebrates: reptiles Reptilian heart 3 -chambers (except for crocodilians with 4) 2 atria 1 ventricle (2 ventricles in crocodiles and alligators) partially divided, decreases mixing may stop sending blood to lungs when not breathing

Different adaptations of the cardiovascular systems in vertebrates: birds and mammals 4 chambered heart: 2 atria 2 ventricles full separation of pulmonary and systemic circuits Advantages 1. no mixing of oxygenated and deoxygenated blood 2. gas exchange is maximized 3. separation allows for pulmonary and systemic circuits to operate at different pressures Importance 1. Endothermic high nutrient and O 2 demands in tissues 2. Numerous vessels great deal of resistance, so requires high pressure

Blood flow in mammals R side of heart: L side of heart: pulmonary circuit systemic circuit one way valves: atrioventricular valves semilunar valves

Blood flow in mammals 1. right atrium receives O 2 -poor blood from superior and inferior venae cavae 2. from right atrium into the right ventricle through the tricuspid valve 3. pumped into the pulmonary artery through the pulmonary semilunar valve to lungs 4. O 2 -rich blood from lungs is returned to the left atrium via the pulmonary veins 5. enters the left ventricle via the mitral or bicuspid valve 6. exits the left ventricle into the aorta via the aortic semilunar valve 7. circulated to body tissues