By Derek, Eric, and Zack

Evolution of the Circulatory System and gas exchange: early organisms No circulatory system Gas exchange through direct diffusion of gases with the environment Gastro Vascular Cavity increase surface area Phylum: Protists Porifera Cnidarians Ctenophores Platyhelminthes

Open circulatory system Phylum: Arthropods Mollusks (except Cephalopods) Organs bathed in intercellular fluid rather than surrounded by vessels. Heart used to create a current Gas exchange through gills or air sacs

Echinoderms Specialized circulatory system Water vascular system (opened or closed) Aids in the transport of food, gases, and waste Papulli : gills aiding in gas exchange

Closed circulatory System Blood inside vessels A chambered heart pumps blood throughout the body Usually well developed organs for circulation and gas exchange Phylum: Annelids Mollusks (Cephalopods) Chordates Fish (2 chambered) Reptiles(3 chambered) Mammals and birds(4 chambers)

Humans Circulatory system and gas Exchange Overview Four chambered heart Double circulation Blood vessels Blood pressure Blood Lymphatic system Lungs (alveoli, diaphragm, trachea) Interdependence of circulatory system and gas exchange Homeostasis Diseases

Human Heart 4 chambers (2 atria and 2 ventricles) Cardiac muscle tissue Function: To pump blood around the body in vessels Important parts: Sinoatrial node (pacemaker) Atrioventricular node Atruim (blood entering) Ventricle (blood exiting) Apex Septum

Double Circulation Definition: Blood passes through the heart twice before completing a cycle around the body Advantages: Maintain velocity of blood Increased blood pressure to organs One heart makes coordination easy

Blood vessels Transport blood around the body and contain it in a permeable wall (endothelium) Types: Veins Arteries Capillaries Veins and arteries also have smooth muscles and connective tissues surrounding the vessel (main purpose is to maintain blood pressure)

Blood Pressure Fluids flow from high to low pressures and by contracting, the heart becomes the high forcing the blood away from the heart Aids in the support of the human body Aids in the delivery and return of blood back to the heart Blood pressure also caused by the contraction of smooth muscles and other nearby muscles

Blood Plasma (55%): water mixed with ions, proteins, hormones, waste products, and cells Cell types (45%): Erythrocytes (RBC) Leukocyte (WBC) Platelets Hemoglobin bind O2 and transports it to cells. It also transfers CO2

Lymphatic system Due to high pressures in the vessels, blood leaks constantly from capillaries. Most of the blood is reabsorbed through osmotic pressure. The rest is collected by the lymphatic system The lymphatic system then directs the absorbed fluid, now lymph, to the heart where it reenters the circulatory system

Lungs and the respiratory system Function: bring gas from the outside and aid in the exchange of gases from the environment with the ones produced by the body Parts: Alveoli – increases surface area for gas exchange Diaphragm – muscle used for pulling in air Trachea – tube that leads air to and from the lungs Other functions: Alter pH of blood through altering levels of CO 2 in blood Filter out small clots and air bubbles in blood vessels

Interdependence of circulatory system and respiratory system With out the circulation system, none of the cells inside the organism will get any oxygen and will die. By supplying them with and taking away gases, other cells can go about their functions that will overall help the body, either it be muscle cells for capturing and eating food, neurons used in thinking about science, or any of the other many tissue types in the human body, each with a specialized task.

Homeostasis The main purpose of the circulatory and respiratory system in to bring high levels of oxygen and other nutrients to cells that can not get it on their own while taking away waste products and gases that would be harmful if the concentrations increased By constantly moving blood through the body, cells can live happily and specialized with their needs being met and their garbage taken away. Analogy: the circulatory system is like servants who bring food and take away the leftovers for their lazy overlords

Diseases Rheumatic Fever Caused by a fever, a damaged heart valve at birth can become damaged further Heart attack/Stroke the blockage of a vein or artery from something, usually plaque or platelets, in the heart or the brain respectively Anemia Deficiency of hemoglobin in Red Blood Cells (RBC) or the deficiency of RBC Tuberculosis Infection of Mycobacterium tuberculosis that leads to increase mucus creation in trachea