BIOL 1108 1st EditionExam # 4 Study GuideLearning Objectives:XVI: Transport & Circulatory System1. Compare and contrast open and closed circulatory systems: Open circulatory system – circulatory fluid (hemolymph) bathes all organs/tissues in the body. Has less surface area to bypass to transfer waste/nutrients. Hemolymph travels through sinusus (open spaces around the organs) and it is also interstitial fluid. Slower blood flow due to less blood pressure and is moved by animals’ moving muscles. There is chemical exchange directly with the body cells. Closed circulatory system: Chemical exchange happens between the blood and interstitial fluid and also between the interstitial fluid and the body cells. Blood is enclosed in vessels at all timesand has a higher blood pressure due to the contraction of the chambers of the heart pushing the blood. Valves prevent backflow [tricuspid and mitral valve are atrioventricular valves that connect the atrium and ventricles and have a chord that pulls at the opposite end of the valve and causes the valve to constrict if there is blood flowing the opposite direction. Found in most vertebrates and some animals contain hemolymph as well as blood. 2. Label the blood vessels of a closed circulatory systems:There are three main types of blood vessels: Arteries carry blood away from the heart, Capillaries are throughout tissues where gas exchange happens due to the thinner walls of the vessels, and Veins carry the blood back to the heart. There are two or more chambers in vertebrate hearts: The Atrium is where blood enters the heart and the Ventricle is where blood exits with pumped out. Blood flow  From body: capillaries of head and forelimbs contain oxygen-poor blood that flows to the ANTERIOR VENA CAVA (right side, “superior vena cava”), capillaries of abdominal organs and hind limbs contain oxygen-poor blood that flows to the POSTERIOR VENA CAVA (alsoright side, “inferior vena cava”)  anterior vena cava and posterior vena cava join and pump oxygen-poor blood into the RIGHT ATRIUM  blood is pumped from the right atrium to the RIGHT VENTRICLE and then exits the heart through the PULMONARY ARTERY  blood travels through the PULMONARY CIRCUIT and returns to the heart through the PULMONARY VEIN as oxygen-rich blood  it enters the LEFT ATRIUM and is then pumped to the LEFT VENTRICLE  exits the heart as oxygen-rich blood through the AORTA  oxygen-rich blood flows through the body – losing oxygen while traveling through the CAPILLARIES and then returns to the ANTERIOR and POSTERIOR VENAE CAVAE as oxygen-poor blood. Carotid artery: delivers oxygen-rich blood to the head/brain. Auxiliary artery: delivers to the arms. Aorta: delivers blood to the legs and torso.Circulation between the heart and lungs  pulmonary circulation / Circulation between the heart and tissues  systemic circulation. 3. Describe the evolution of the 4-chambered heart from a 2-chambered heart and explain the advantages/disadvantages of the amphibian and reptile heart.  2-chambered heart: Found in bony fish, rays, and sharks. Contains only systemic circulation (SINGLE CIRCULATION), where oxygen-poor blood flows from atrium to ventricle, leaves throughartery, goes to gills and becomes oxygenated, flows to systemic capillaries and loses oxygen, then returns to the atrium through a vein. Advantages/disadvantages: Fish are exothermic and therefore do not need an efficient circulatory system. For single circulation, blood passes through 2 capillary beds before returning to the heart. In each capillary bed, blood pressure drops substantially. Therefore, after the blood flows through the gills, the rate at which it flows through the body is limited. However, the contraction and relaxation of the fish’s muscles as it swims helps to speed up the process.  3-chambered heart: Found in amphibians. Contains two circuits of blood flow: PULMOCUTANEOUS and SYSTEMIC. Pulmocutaneous is when the capillaries flow both to the lungs and the skin. Blood flow: Oxygen-poor blood from body  right atrium  single ventricle where ~ 90% of oxygen-poor blood from the right atrium is sent to the pulmocutaneous circuit and then returns to the left atrium as oxygen-rich blood  flows to single ventricle again where most of the oxygen rich blood is pumped to the systemic circuit  returns to right atrium as oxygen-poor. Adavantages/disadvantages: Adv. – Amphibians can adjust their circulation when under water, where they mostly shut off blood flow to their temporarily ineffective lungs. The blood continues flowing to the skin, which acts as the sole site of gas exchange while underwater. Disadv. – oxygen-poor and rich blood gets mixed some in ventricle before being sent to its respective places, which is inefficient.  Reptiles (except birds): They have an IMCOMPLETE SEPTUM that partially divides the single ventricle into left and right chambers. From the left ventricle chamber, there are two aorta (left systemic and right systemic). Left systemic remain mostly oxygen-rich blood, while the right systemic aorta mixes slightly with the oxygen-poor blood from the right ventricle chamber. Advantages/disadvantages: Adv. – allows some control of the relative amount of blood flowing to the lungs and the body. Disadv.- some oxygen-poor blood is being pumped throughout the body, which is wasting energy.  4-chambered heart: Evolution of 4-chambered heart in birds and mammals in convergent. However, it is necessary to have a very efficient circulatory system to be endothermic. So the fact that birds and mammals are both endothermic is related to having a powerful circulatory system. Advantages/Disadvantages: Adv.- Because mammals & birds are endotherms, theyrequire 10X the amount of fuel and oxygen delivered to tissues, and to remove 10X the amount of waste. The separate pulmonary and systemic circuits make this possible because the blood is re-pressurized in the heart after passing through the pulmonary circuit. The blood pressure is actually higher in the systemic circuit than the pulmonary circuit. This contrasts greatly with the single circulation system, which significantly loses blood pressure after gas exchange. Disadv.- It requires more energy and it might cause complications due to the fact that both sides have to work in synchronization. 4. Draw and describe the structural components of your cardiac muscle and their location relative to each other.