Circulatory System Transport systems in animals

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

Transport at the cellular level  Cell membrane  Passive transport (diffusion, facilitated diffusion, osmosis)  high concentration of solutes to low concentration of solutes  no need to expend energy  Active transport  spending energy  moving materials from low concentration to high concentration of solutes  Transport of large molecules  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  manufacturing and transport facility  proteins produced in rough ER are packaged in vesicles  Golgi apparatus  modification and storage facility  receiving end and shipping end  Vacuole  large membrane bound sacs  usually stores undigested nutrients

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  Atrium  Ventricle  Blood vessels  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: oxygen-rich 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:  pulmonary circuit  L side of heart:  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