11/7/2014 Circulatory System 1 11/7/2014 Diffusion is insufficient for transporting substances over long distances It takes 1 second for glucose to diffuse from 100 micro meters It will take 3 hours to diffuse 1 mm! Circulatory systems solves this problem by ensuring that no substances has to diffuse very far toenter or leave the cell! And it connects the cells to the organs that exchange molecules. Transport in small invertebrates Sponges Cnidarians Flatworms 2 11/7/2014 Transport in invertebrates Roundworms Fluid contained within the body cavity of pseudocoelome functions to transport nutrients and wastes but these animals do not have a heart or blood vessels. Open Circulatory System blood is pumped from the heart through blood vessels but then it leaves the blood vessels and enters body cavities, where the organs are bathed in blood. Mollusks and arthropods: (except cephalopods) have an open circulatory system. 3 11/7/2014 Open Circulatory System Arthopods The coelom carries blood (hemolymph). It is called a hemocoel The blood of insects is colorless because it lacks respiratory pigments; it functions to carry nutrients, not gases. Crustaceans and some arachnids have hemocyanin a protein with copper, not within a cell Animals with open circulatory systems generally have limited activity due to limitations in the oxygen delivery capability Insects are able to be active because gas exchange is via a tracheal system. Closed Circulatory System Blood is contained within blood vessels. Valves prevent the backflow of blood within the blood vessels. This type of circulatory system is found in vertebrates and several invertebrates including annelids, squids and octopuses 4 11/7/2014 Closed Circulatory System Earthworms have a dorsal and ventral blood vessel that runs the length of the animal. Branches from these vessels are found in each segment. There are five vessels that pump blood from the dorsal vessel to the ventral vessel. Earthworms have red blood (due to the pigment hemoglobin) but they have no cells. Hemoglobin binds with oxygen to carry it to the tissues. Parts of the circulatory system and their functions PUMP: Atria: __________________ Ventricles: ______________ PLUMBING: Arteries: __________________ Veins: ______________ Capillaries: _____________ Function of pulmonary and systemic circuit? 5 11/7/2014 Capillaries are the sites for diffusion Types of closed circulatory systems in fish The gills with many capillaries blood pressure is low after going through the gills. Low- pressure blood from the gills then goes directly to the body, which also has a large number of capillaries. The activity level of fish is limited due to the low rate of blood flow to the body. 6 11/7/2014 Types of closed circulatory systems in amphibian Blood from the lungs goes to the left atrium. Blood from the body (systemic flow) goes to the right atrium. Both atria empty into the ventricle where some mixing occurs. The advantage is________________________________________________________________ Types of closed circulatory systems in mammals and birds Birds and mammals (also crocodilians) h have a four-chambered heart which acts as two separate pumps. he high rate of oxygen-rich blood flow through the body enables birds and mammals to maintain high activity levels. 7 11/7/2014 Form reflects function Arteries have _______layer of muscle Atrium: (thin walled) Veins have _______layer of muscle Ventricle: (thick walled) pulse! Capillaries have _______layer of cells Why is the left ventricle thicker? How is backflow prevented? One million persons die each year of a heart attack Damage to walls of arteries due to smoking and inactivity PLUS diet high in trans fats/ sat fats and low in unsat fats Causes: Atherosclerosis (buildup of plaque in arteries, reducing flow) Which can happen in coronary arteries ( supply blood to the heart muscle) Leading to a heart attack (failure of the heart to function properly) 8 .