Blood Cells & Regulation in the Circulatory System AP Biology 2006-2007 Blood & blood cells Blood is a tissue of cells in a fluid plasma = fluid (55% of volume) ions (electrolytes), plasma proteins, nutrients, waste products, gases, hormones cells (45% of volume) RBC = erythrocytes transport O2 WBC = leukocytes defense platelets blood clotting AP Biology Components of Blood tissue AP Biology Plasma proteins Synthesized in liver & lymph system fibrinogen clotting factor blood plasma with clotting factors removed = serum albumins buffer against pH changes, help maintain osmotic balance & blood’s viscosity globulins immunoglobins = antibodies immune response to combat foreign invaders AP Biology Blood cell production Stem cells pluripotent cells in bone marrow produce all types of blood cells cells differentiate in bone marrow & lymph tissue AP Biology Red blood cells Function O2 transport Structure small biconcave disks 5 liters of blood in body large surface area = 25 trillion lack nuclei & mitochondria RBC more space for hemoglobin iron-containing protein that transports O2 generate ATP by anaerobic respiration only last 3-4 months (120 days) ingested by phagocytic cells in liver & spleen ~3 million RBC destroyed each second AP Biology produce ~3 million RBC every second to replace Hemoglobin Protein with 4° structure O2 carrier molecule 250,000 molecules hemoglobin/RBC each Hb molecule carries 4 O2 each RBC carries 1 million O2 AP Biology Control of heart Evolution of system to control heart beat timely delivery of O2 to cells is critical cells of cardiac muscle are “self-excitatory” contract without any signal from nervous system each cell has its own contraction rhythm, so have to coordinate them cells synchronized by sinoatrial (SA) node “pacemaker” cells in wall of right atrium sets rate & timing of cardiac cell contraction AP Biology SA node & Electrical signals Pacemaker generates electrical impulses across heart signal also transmitted to skin = EKG or ECG stimulates ventricles allows atria to empty to contract from completely before bottom to top, driving ventricles contract blood into arteries AP Biology Regulation of heart rate Physiological cues affect heart rate nervous system speed up pacemaker slow down pacemaker heart rate is compromise regulated by opposing actions of these 2 sets of nerves hormones epinephrine from adrenal glands increases heart rate body temperature activity exercise, etc. AP Biology Regulation of blood volume / pressure Hormone regulation ADH (antidiuretic hormone) from pituitary BP causes kidneys to reabsorb more water aldosterone from adrenal gland BP causes kidneys to reabsorb Na+ & water atrial natriuretic hormone from heart (right atrium) promotes excretion of Na+ in urine BP nitric oxide from blood vessel cells dilates blood vessels BP nitroglycerin & Viagra release nitric oxide AP Biology Cascade reaction Blood clotting chemical platelets fibrin protein fibers emergency seal the hole build clot signals Powerful evolutionary adaptation emergency repair prevents excessive blood loss Prothrombin Thrombin Ooooooh! AP Biology Fibrinogen Fibrin Zymogen! Cardiovascular disease Leading cause of death in U.S. plaques develop in inner wall of arteries narrowing channel stroke, heart attack, atherosclerosis, arteriosclerosis, hypertension (high blood pressure) tendency inherited, but other risk factors: smoking, lack of exercise, obesity, diet rich in fat AP Biology Cardiovascular health (U.S. 2001) Heart Disease 696,947 Cancer 557,271 Stroke 162,672 Chronic lower respiratory diseases 124,816 Accidents (unintentional injuries) 106,742 Diabetes 73,249 Influenza/Pneumonia 65,681 Alzheimer's disease 58,866 Nephritis, nephrotic syndrome & 40,974 nephrosis Septicemia 33,865 AP Biology Heart Disease Heart disease death rates 1996-2002 Adults ages 35 and older AP Biology Women & Heart Disease Death rates for heart disease per 100,000 women, 2002 Risk factors Smoking Lack of exercise High fat diet Overweight Heart disease is 3rd leading cause of death among women aged 25–44 years & 2nd leading cause of death among women aged 45–64 years. AP Biology Thermoregulation Vasodilation & vasoconstriction adjusts blood flow evaporative cooling Vasoconstriction AP Biology Vasodilation Temperature management blood from arteries warms blood in veins 5˚C environmental 36˚C core temperature body temperature Counter-current Warm blood exchange system! Veins Artery Veins Cold blood Capillary bed AP Biology My feet are cold standing around waiting… Ask some questions, already! AP Biology 2006-2007 Ooooooh! Zymogen! Blood Osmolarity ADH pituitary increased increase water thirst reabsorption high nephron blood osmolarity blood pressure JuxtaGlomerular low Apparatus (JGA) increased adrenal water & salt nephron gland reabsorption renin aldosterone angiotensinogen AP Biology angiotensin Ooooooh! Zymogen! Stomach Functions food storage can stretch to fit ~2L food disinfect food HCl = pH 2 kills bacteria breaks apart cells chemical digestion pepsin enzyme breaks down proteins secreted as pepsinogen activated by HCl AP Biology Ooooooh! Zymogen! Pancreas Digestive enzymes What stops pancreas peptidases from digesting trypsin itself trypsinogen chymotrypsin chimotrypsinogen carboxypeptidase small intestines procarboxypeptidase Explain how this is a molecular example of structure-function theme. AP Biology Cascade reaction Blood clotting chemical platelets fibrin protein fibers emergency seal the hole build clot signals Powerful evolutionary adaptation emergency repair prevents excessive blood loss Prothrombin Thrombin Ooooooh! AP Biology Fibrinogen Fibrin Zymogen!