Chapter 16 1 The Bodys Transport System Warm

Chapter 16 -1 The Body’s Transport System Warm up: What is the function of the cardiovascular system? www. brainpop. com circulatory system

A. The Cardiovascular System § The cardiovascular System: (circulatory system) consists of the heart, blood vessels and blood. § Carries needed substances to cells and carries waste products away from cells. § Blood contains cells that fight disease.

1. Delivering Needed Materials § Carries oxygen from lungs to other parts of body § Also transfers the glucose your cells use

3. Removing Waste Products § Picks up wastes from cells § Example, carrying CO 2 back to lungs to be expelled

3. Fighting Disease § Transports cells that attack disease causing microorganisms § Helps you from getting sick and if you get sick, it fights the microorganisms

B. The Heart § The heart is hollow, muscular ORGAN that pumps blood throughout the body. § Each heart beat it pushes blood through blood vessels § Size of your fist! § Center of chest § Behind sternum, inside rib cage § Cardiac muscle doesn’t tire § www. brainpop. com heart

1. The Heart’s Structure § Right Side Vs Left Side § Sides separated by septum § Each side has 2 chambers upper chamber and lower chamber § Upper Chambers Atrium or Atria (plural) § Receives blood that comes INTO heart § Right Atrium a group of cells called the pacemaker sends signals to make heart beat § Lower Chambers Ventricle § Pumps blood OUT of the heart § Atria are separated from ventricles by valves a flap of tissue that prevents blood from flowing backward

2. How the Heart Works § Two main phases: 1. Heart muscles relaxes and heart fills with blood 2. Heart muscles contract and pumps blood forward § Your heartbeat, lub-dup, can be heard during the pumping phase § Heart muscles relax blood flows in to chamber atria contract squeezes blood out of atria through valves into ventricles contract valves close (lub) squeezes blood into vessels valves in ventricles shut (dup) blood exerted into arteries

C. Two Loops § After leaving the heart your blood travels through blood vessels § Arteries: blood vessels that carry blood away from the heart. § From arteries blood flows to capillaries. Capillaries are narrow vessels where substances are exchanged between the blood and body cells. § From Capillaries blood flows to veins. Veins are blood vessels that carry blood back to the heart.

1. Pattern of Blood Flow § 1 st loop blood travels from heart to lungs and back to heart § 2 nd loop from heart to body to heart § Blood travels in 1 direction § Make the entire figure 8 loop in 1 minute

2. Loop One: To the Lungs and Back § Blood from body flows into right atrium it has little oxygen but a lot of CO 2 § Oxygen poor blood dark red § Right atrium right ventricle lungs air in lungs flows into oxygen poor blood in capillaries rich in Oxygen now bright red flows to left side of heart

3. Loop Two: To the Body and Back § Starts in left atrium with oxygen rich blood from the lungs § Moves to left ventricle pumped to aorta (the largest artery in the body) passes through branching arteries capillaries in different body parts oxygen leaves blood into cells CO 2 from cells enters blood low in oxygen blood returns to right atrium

D. Arteries § Coronary arteries carry to the heart itself

1. Artery Structure § Very thick 3 cell layers § Innermost layer is smooth epithelial cells § Smooth surface allows blood to flow freely § Middle layer muscle tissue § Outer layer flexible connective tissue § Arteries able to withstand lots of pressure

2. Pulse § Pulse is caused by the alternating expansion and relaxation of the artery wall § Take your pulse rate to determine how fast your heart is beating

3. Regulating Blood Flow § Muscles contract to restrict blood flow and relax to increase blood flow § After you eat and your stomach and intestines need a larger blood supply, the arteries leading to that area relax to allow more blood flow § When you are exercising, the arteries to those area constrict to reduce blood flow… why? ? ?

E. Capillaries § Capillary walls are only one cell thick § So materials can pass through them easily § Exchanges of substances happen here § Diffusion: the process by which molecules move from an area of higher concentration to an area of lower concentration

F. Veins § Carries blood back to heart § 3 layers with a muscle layer in the middle § Walls thinner than arteries § Skeletal muscle helps move blood through veins (1) § Larger veins have valves (2)…. Why? § To prevent blood from flowing backwards § Breathing pressure, when you breath, helps push blood along (3)

G. Blood Pressure 1. What Causes Blood Pressure? § Similar to water in a hose § Blood exerts a force against the walls of blood vessels blood pressure § Caused by the force of the ventricles when they contract § Blood moves away from heart blood pressure decreases § Highest pressure at arteries

2. Measuring Blood Pressure § Sphygmomanometer § Millimeters of mercury… why? § 1 st number when ventricles contract § 2 nd number which is lower is when the ventricles relax § Contraction/relaxation § www. brainpop. com blood pressure