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Circulatory System Ms. Day AP Biology
Circulatory System Ms. Day AP Biology
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What is a Circulatory System?
It is a means of getting stuff around the body Oxygen Nutrients Wastes
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Do All Animals Have a Circulatory System?
NO Some animals rely on only DIFFUSION to move substances throughout their bodies NOT EFFICIENT; very slow LIMITS SIZE – if you’re going to use diffusion to transport substances, then you have to be SMALL.
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So How is a Circulatory System Different from Diffusion?
Involves a “pump” and some type of vessels (“plumbing”) to move materials more quickly and in large amounts throughout the body. Also involves a tissue designed to carry some of these materials (ex: BLOOD)
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Open Circulatory Systems
ARTHROPODS and most MOLLUSKS Multiple cell layers diffusion is not adequate. OPEN circulatory system NO distinction between blood and fluid between cells (called interstitial fluid)
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CLOSED Circulatory system
Annelida, some mollusks (squid/ocutopus) & vertebrates Blood is in blood vessels and never leaves Blood distinct from interstitial fluid 1+ hearts pumps blood into vessels that get smaller and smaller until reach organs. Nutrients diffuse into organs; wastes from organs diffuse into blood vessels
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Open vs. Closed Circulatory System
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Basics of the Vertebrate Heart
Atrium – receiving chamber Receives blood from some location Not very muscular May have 1 or 2 atria Ventricle – pumping chamber Pumps blood to some location VERY muscular May have 1 or 2
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Types of Blood Vessels Arteries (A for AWAY)
carry blood away from heart Veins carries blood back to heart Capillaries tiny blood vessels (arteries) Gas exchange occurs here
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Basics of Vertebrate Blood Vessels Structure
3 main types of blood vessels – Arteries, Veins and Capillaries Arteries Arterioles – smaller branches of the arteries that take blood to capillaries Capillaries Smallest vessels Contained within organs Thin walls Diffusion of nutrients/oxygen into organs and wastes out of organs occurs here Venules – capillaries converge to create venules which carry blood to veins Veins
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Birds and Mammals Why do birds and mammals have the most efficient circulatory system? ENDOTHERMS – maintain body temperature by using heat from metabolism Requires LOTS of energy MORE oxygen per gram of body weight than other animals (ectothermic animals)
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Mammalian Heart 2 ventricles Contains veins and arteries
Size of fist and under sternum in humans Made of cardiac muscle tissue 2 atria with thin walls (A for Away) Receiving chambers – deliver blood to ventricles 2 ventricles Thick walls –pumps blood from heart to entire body (not just lungs) Pumping chambers Contains veins and arteries
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The heart has four chambers
V V This is a vein. It brings blood from the body, except the lungs. These are arteries. They carry blood away from the heart. 2 atria Coronary arteries, the hearts own blood supply 2 ventricles The heart has four chambers
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Heart Valves = prevent backflow of blood
Artery to Lungs Artery to Head and Body Vein from Lungs Vein from Head and Body Right Atrium Left Atrium Valve Valve Right Ventricle Left Ventricle
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CIRCULATORY SYSTEM
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This means it has two parts parts.
Humans (& other mammals) have a circulatory system is a double circulatory system. This means it has two parts parts. Lungs Body cells the right side of the system deals with deoxygenated blood. the left side of the system deals with oxygenated blood. Think: Love Left is oxygenated
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Heart Valves = prevent backflow of blood
Artery to Lungs Artery to Head and Body Vein from Lungs Vein from Head and Body Right Atrium Left Atrium Valve Valve Right Ventricle Left Ventricle
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Chambers of the Heart
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Blood flow through the heart
Into vena cava Into right atrium Down to right ventricle Out pulmonary artery to lungs Gets O2 and dumps CO2 Back to heart through pulmonary vein Into left atrium Down to left ventricle Out aorta to body
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Largest artery Largest vein
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TO BODY TO LUNGS E H FROM LUNGS G D FROM BODY F A C B
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Mammalian Heart When blood is pumped into the elastic- walled arteries, they stretch. Pulse – rhythmic stretching of the arteries caused by pressure of blood driven by ventricles Heart rate – number of times the heart beats per minute
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Mammalian Heart Heart sounds Heard with stethoscope
Caused by closing of valves Lub-dup Lub - created from recoil of blood against closed AV valves Dup – created from recoil of blood against semilunar valves Blood Pressure Pushing of blood against walls of vessels
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Two Main Parts of Circulatory System
Pulmonary Circuit Blood goes from heart to lungs to pick up O2 and release CO2 Systemic Circuit Blood pumped out of heart to the rest of the body (systems) The path of the blood through the body is HEARTLUNGS HEARTBODYHEART
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Only vein that carries OXYGENATED blood Pulmonary Artery:
Pulmonary Vein: Only vein that carries OXYGENATED blood Pulmonary Artery: Only artery that carries DEOXYGENATED blood
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The Circulatory System- The Pathway
Pulmonary artery Lungs Pulmonary vein Head & arms Aorta Main vein Right Left Liver Digestive system Kidneys Legs
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Blood flow through the body uses blood vessels
Arteries take oxygenated blood away from the heart No valves Break into capillaries thicker
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Capillaries Very small vessels
Gases diffuse across very thin wall of small vessels Gas exchanges here !!! O2 and CO2 Carries oxygenated blood Nutrients and oxygen leave the blood and go into the body tissue
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Veins takes deoxygenated blood back to heart Have one-way valves
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Blood Flow Blood flows MUCH faster in aorta 30 cm/sec
Blood flows MUCH slower in capillaries (DECREASES in velocity)
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Blood Flow Seems like blood should actually accelerate in capillaries
Like putting your thumb over the end of a water hose When you NARROW the opening, the velocity of the fluid must get faster to get the same volume through. However, the total NUMBER of capillaries AND their TOTAL WIDTH TOGETHER makes them MUCH wider (when taken all together) than the single aorta. Thus, velocity slows A LOT
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Blood has 4 parts Red blood cell White blood cell Plasma Platelets
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Red Blood Cells (Erthyocytes)
A disc that is round and flat without a nucleus can change shape to an amazing extent, without breaking, as it squeezes single file through the capillaries. contain hemoglobin and iron, a molecule specially designed to hold oxygen and carry it to cells that need it.
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White Blood Cells (Leukocytes)
There are many different types and all contain a big nucleus. The two main ones are the lymphocytes and the macrophages. Macrophages “eat” and digest micro-organisms. Some lymphocytes fight disease by making antibodies to destroy invaders by dissolving them. Other lymphocytes make antitoxins to break down poisons.
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Platelets Platelets are bits of cell broken off larger cells.
Platelets produce tiny fibrinogen fibers to form a net. This net traps other blood cells to form a blood clot.
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Plasma A straw-colored sticky liquid that carries the cells and the platelets which help blood clot; mostly water It also contains useful things like: Carbon dioxide Glucose Amino acids Proteins Minerals Antibodies Vitamins Hormones Waste (urea)
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