Circulation in Organisms How do organisms transport nutrients, waste, and gases?

Unicellular Organisms: Bacteria, Protists and Porifera Diffusion Resources move across membrane Active transport Endo and exocytosis Pumps and ion channels Cytoplasmic streaming Porifera also use the beating of flagella in the gastric cavity

Multicellular Direct exchange via membrane not efficient Solution? Evolution Complex systems specialized for transport/exchange  Circulatory System  Respiratory System

Cnidarians and Platyhelminthes Use the gastrovascular cavity as a surface for diffusion The gastrovascular cavity branches throughout the organism Does not require a true circulatory system Body wall only two cells thick. Inner layer cells have direct access to nutrients

Basic Components of The Circulatory System of Multicellular Organisms Circulatory fluid (Blood) A set of tubes (Blood Vessels) Where the blood moves throughout the body A muscular pump (Heart or analogous structure) Where the heart powers the system by elevating the hydrostatic pressure of the blood

Open Circulatory System Includes Insects, Arthropods, and most Mollusks Blood bathes internal organs No distinction between blood and interstitial fluid Hemolymph Heart pumps hemolymph into sinuses Spaces around organs Location where chemicals are exchanged Body movements help circulation

Open Circulatory System Advantages Lower hydrostatic pressure Less energy needed Require less energy to build and maintain Other purposes Example Molluscs and Aquatic Arthropods use the open circulatory system as a hydrostatic skeleton for support

Closed Circulatory System Includes Earthworms, Squids, Octopuses, and all Vertebrates Enclosed in vessels Segregation of interstitial fluid and circulation fluid Exchanged through diffusion between the blood and interstitial fluid

Closed Circulatory System Advantages Higher pressure More effective in transporting circulatory fluids Example – Of invertebrates only the large and active squids and octopuses have this system High demand for oxygen

The Cardiovascular System. Heart One or two atria – receives blood going into heart One or two ventricules – pump blood out Blood Vessels Arteries – carries blood away from heart Arterioles Capillaries – microscopic vessels Capillary beds Veins - carries blood into heart Venules Higher metabolic rate = More complex, more powerful hearts

The Blood: Made in the bone marrow (red blood cells) Transports nutrients, wastes, gasses, hormones. 55% Plasma 90% Water, with dissolved nutrients  Salts, Electrolytes (Na, K, Ca, Mg, Cl)  Glucose  Proteins (albumin, fibrinogen)  Immunoglobulins

The Blood: 45% Cellular – RBC, WBC, Platelets. RBC (erythrocytes) – contain no nucleus, just hemoglobin (iron attracts oxygen.) Erythropoietin regulates # of RBC WBC (leukocytes) – immune system (T-cells, B-cells, etc.) Platelets – blood clotting (fragments of large cells called megakaryocytes.)

Blood Clotting (Coagulation): Damaged blood vessel Platelets arrive Plug forms Prothrombin Thrombin (inactive) (active form) Fibrinogen Fibrin (blood protein) (scab produced) Howstuffworks "Blood Clotting Process "

Fish Circulation Heart – 2 chambers 1 atrium 1 ventricle Single Circuit Blood pressure is quite slow! Must travel through two capillary beds through each circuit Blood movement aided by swimming

Ventricle Atrium Gill Capillaries Systemic Capillaries

Amphibian Circulation Three-chambered heart Two Atria One Ventricle – pumps blood into forked artery Blood travel Pulmocutaneous Circulation – to lungs and skin Back to Heart Systemic Circuit Two circuit Some mixing of blood via the single ventricle

Atrium Ventricle Atrium

Reptiles (Except Birds) Circulation Three-chambered heart + septum Two Atria One Ventricle Blood travel Pulmonary Circulation Back to Heart Systemic Circuit Two circuit Some mixing of blood via the single ventricle is reduced

Four-chambered heart Two Atria Two Ventricle Blood travel Pulmonary Circulation Back to Heart Systemic Circuit Two circuit No mixing of oxygen-poor and oxygen-rich blood except for exceptions Mammals and Birds Circulation

To better understand the heart of mammals… Human Heart Atria Storage (Collection) chambers for blood returning to heart Relatively thin walls  Contraction involves filling the ventricles

Human Heart Ventricles Release chambers for pumping blood out of heart Relatively thicker walls Much, much stronger than the atria Example - the left ventricle must pump blood throughout the systemic circuit

Nodes Pacemaker – Sinoatrial (SA) node– sets timing of beats, found in wall of right atrium Sends electrical signals to Arterioventricular (AV) node Trigger ventricles to contract Pacemaker effected by: Nervous system Adrenaline Body temperature

Blood Pressure Low in veins, high in arteries Normal resting adult – 120/80 Systolic number (120) is a measurement of the pressure when the ventricles contract Diastolic number (80) is a measure of the pressure when the heart relaxes

Pathway of Blood Enter via Vena Cava Right atrium Right atrioventricular valve (Tricuspid valve) Right ventricle Pulmonary semilunar valve Pulmonary artery Lungs Pulmonary vein Left atrium Bicuspid valve Left ventricle Aortic semilunar valve Aorta Blood to the body

The Heart Beneath sternum Beats 70 beats per min. on average Pumps 5 quarts of blood per minute All your blood Made of cardiac muscle cells – will contract even when the heart is removed EKG (electrocardiogram) – detect electrical signals sent out by specialized parts of the heart

Varicose Veins YouTube - What Causes Varicose Veins? YouTube - What Causes Varicose Veins?

Spider Veins Spider veins are abnormal skin veins that are enlarged. They typically are red or blue-red.

Video Clip The Heart cfm?guidAssetId=800CA676-82D A- DC F&blnFromSearch=1&produ ctcode=US cfm?guidAssetId=800CA676-82D A- DC F&blnFromSearch=1&produ ctcode=US

Animations Anatomy of the Heart Animation Sample Heart Contraction and Blood Flow (SA and AV node also) Heart Contraction and Blood Flow 16a.swf Shows blood flow through the heart. 16a.swf

The FOUR chambered Heart: Right Atrium: deoxygenated blood enters heart from superior and inferior vena cava (large veins). Right Ventricle: Blood is pumped into this chamber through the tricuspid valve. Blood is pumped to the lungs through semilunar valve and through the pulmonary arteries. Blood is oxygenated. Left Atrium: Blood flows back into heart from lungs through the pulmonary veins, and is pumped out through the bicuspid valve. Left Ventricle: oxygen rich blood is pumped through the aortic valve into the aorta, which transports it to the body.