DO NOW Describe the journey of a drop of blood starting in the heart using the 4 chambers of the heart and the 2 dif ferent types of circulation. Use these words: Systemic Circulation, Pulmonary Circulation, Left Atrium, Right Atrium, Left Ventricle, Right Ventricle Identify the molecules being exchanged at the lungs during circulation. Identify the molecule being synthesized as a waste product in the body tissues.
Objective: Howdo the threetypes of bloodvessels helpthe circulatorysystemmaintainhomeostasis?
REGENTS REVIEW Which two systems are most directly involved in providing molecules needed for the synthesis of fats in human cells?1. digestive and circulatory2. excretory and digestive3. immune and muscular4. reproductive and circulatory
HEARTBEAT To be ef ficient, the heart must beat in a coordinated way Two places that set the pace for the heart beat: One in the atria – SINOATRIAL NODE One in the ventricles – ATRIOVENTRICULAR NODE These are the PACEMAKERS because they set the pace for heartbeat
HEARTBEATAs the pacemaker’s signal spreads, the whole heart contracts…Important: Heart rate depends on the body’s need for oxygen The more you exercise, the higher your heart rate gets – why?
REGENTS REVIEW Humans breathe more rapidly during exercise than before it because during exercise the blood contains1. an increased level of oxygen2. a decreased number of red blood cells3. an increased level of carbon dioxide4. a decreased amount of hemoglobin
AFTER THE BLOOD LEAVES THE HEART… The blood moves through three dif ferent types of blood vessels BLOOD VESSELS – tissues that carry blood; examples are below After the blood leaves the VENTRICLES travels in this order: 1. ARTERIES 2. CAPILLARIES 3. VEINS
CRITICAL THINKING If the blood travels in the following order – arteries, capillaries, and veins – which blood vessel will have the highest pressure? Why?
1. ARTERIESStructure: Thick, elastic walls to withstand the high pressure First blood vessel after the heartFunction: Large vessels carry blood AWAY from the heart to tissues Arteries coming from the right ventricle does not have oxygen. Arteries coming from the left ventricle does have oxygen.
2. CAPILLARIESStructure: Smallest blood vessels – like the “side streets” Very thin – blood cells pass through them single fileFunction: Thin walls – sites of nutrient and gas exchange Allow oxygen, nutrients, CO2 to diffuse into and out of tissues very easily! Why can’t the walls of capillaries be thick like arteries?
3. VEINSStructure: Walls thicker than capillaries; not as thick as arteries Many times blood will travel against gravity in veins Valves close and open to ensure blood travels one directionFunction: After passing through capillaries, blood returns to the heart using veins Where do you think you would need valves the most? Why?
REGENTS REVIEW Which statement best describes arteries?1. They have thick walls and transport blood away from the heart.2. They have thick walls and transport blood toward the heart.3. They have thin walls and transport blood away from the heart.4. They have thin walls and transport blood toward the heart.
REGENTS REVIEW Blood normally flows from the capillaries directly into1. small arteries2. small veins3. lymph vessels4. heart atria
BLOOD PRESSURE Pressure created in your vessels by the heart’s contraction Body regulates blood pressure by: Muscle contraction in the walls of the arteries Kidney water balance by kidneys Measure blood pressure by arteries in arm with a SPYGMOMANOMETER (Blood pressure cuf f) Pulse – measured heartbeat represented by blood pressure Increases in arteries
REGENTS REVIEW A pulse can be detected most easily in1. an artery2. a vein3. a capillary4. a lacteal