Seph Rodriguez & Austin Stowell Circulatory system Seph Rodriguez & Austin Stowell

Basic overview Circulatory system includes Heart Blood cells Blood vessels/veins/arteries

Basic overview cont’d Basic functions include Internal distribution of materials i.e. Delivery of O2 Nutrients Hormones Removal of carbon dioxide Ammonia and other metabolic wastes

Blood vessels structure and fucnctions Contain central Lumen lined with endothelium (single layer of flattened epithelial cells) Smooth surface of endothelium minimizes resistance to the flow of blood Surrounding endothelium are layers of tissue that differ among capillaries, arteries, and veins, reflecting their specialized functions

Blood vessels structure and fucnctions Cont’d Capillaries Smallest blood vessels (diameter only slightly greater than red blood cell) Have very thin walls consisting only of endothelium and its basal lamina Facilitates exchange of substances between blood, capillaries, and interstitial fluids

Blood vessels structure and fucnctions Cont’d Veins and Arteries More complex organization than those of capillaries Have 2 layers of tissue surrounding endothelium: outer layer of connective tissue containing elastic fibers, allows vessels to stretch and recoil middle layer contains smooth muscle and more elastic fibers

Differences in arteries and veins Have wall 3x thicker than vein Strong walls accommodate high pressure blood pump by the heart Elastic recoil maintains blood pressure when heart relaxes between heart contractions Thinner walls bring blood back to heart at lower speeds and pressure Valves maintain unidirectional flow of blood in these vessels

Capillaries, Veins and arteries

Capillary functions 5-10% of bodies capillaries have blood flow However each tissues has many capillaries so every part of the body has constant blood flow Capillaries in brain, heart, liver, and kidneys are filled to capacity But other sites’ blood supply varies over time as blood moves from one destination to another

Capillary functions Cont’d Examples include Blood flow to the skin regulates body temperature Blood supply to digestive tract increases after a meal

Blood composition and function Blood is a connective tissue whose cells are suspended in a liquid matrix called plasma Plasma contains dissolved ions referred to as blood electrolytes Is also 90% water dissolve salts are essential to the blood Concentration of ions effects the composition of plasma

Cellular elements Two types of cells suspended in blood plasma Red blood cells (erythrocytes)-transport oxygen White blood cells (leukocytes)-function in defense Blood contains platelets that are involved in the clotting process

Chambers of the heart The heart has 4 chambers Two atria (atrium) Two ventricles Left and right atria Right--recieves oxygen-poor blood and pumps it to the right ventricle Left—receives oxygen-rich blood from the lungs and pumps it to the left ventricle

Chambers of the heart cont’d Left and Right ventricles Right—receives oxygen-poor blood from the right atrium and pumps it to the lungs Left—receives oxygen-rich blood from the lungs and pumps it to the rest of the body

BP can change from minute to minute with changes in: Blood Pressure Blood pressure rises with each heartbeat and lowers whenever the heart relaxes BP can change from minute to minute with changes in: Stress, exercise, stress, or sleep Norm. blood pressure for an adult 20yrs+ should be less than 120/80 mm Hg Less than 120 systolic and less than 80 diastolic

Questionnaire What are the main components of the circulatory system? What are the 3 types of blood vessels? What 2 blood vessels differ in structure/function? List at least 2 differences. The capillaries of which organs are always filled to capacity? What are all of the chambers of the heart and their functions?

Work cited AP BIO Textbook chapter 42 http://www.webmd.com/heart/chambers-of-the- heart http://www.google.com/?safe=active&ssui=on#q=av erage+blood+pressure+in+adults&safe=strict&ssui=on