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UNIT 3 – PART 1. CIRCULATORY & EXCRETORY SYSTEMS. The Circulatory System. Functions. To transport O 2 to the cells of the body so that cells may do cellular respiration To Transport nutrients to the cells of the body To transport CO 2 and cellular wastes away from the cells. Parts. Heart
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UNIT 3 – PART 1 CIRCULATORY & EXCRETORY SYSTEMS
Functions • To transport O2 to the cells of the body so that cells may do cellular respiration • To Transport nutrients to the cells of the body • To transport CO2 and cellular wastes away from the cells
Parts • Heart • Blood Vessels • Blood
Components of Blood • Red blood cells • White blood cells • Platelets • Plasma
What are Red Blood Cells? • Also called erythrocytes • Transport oxygen • Shaped like disks • Produced in the red bone marrow • Contain Hemoglobin • An iron containing protein that binds to oxygen • Gives blood a red color
What are White Blood Cells? • Also called leukocytes • Produced in the red bone marrow • Can live for days, months or even years • Guard against infection, fight parasites, and attack bacteria • Can leave the circulatory system and go into the immune system fighting infection
What are two kinds of White Blood Cells? • Phagocytes (eating cells) • Engulf and digest disease causing bacteria • Lymphocytes • Produce antibodies that are proteins to help destroy pathogens
What are platelets? • Cell fragments needed for clotting • Made in bone marrow • Clotting process • Platelet comes in contact with edges of broken blood vessel and becomes sticky • A cluster of platelets gathers around the wound forming a clot (scab)
What is plasma? • Fluid part of blood (mostly made of water) • Straw colored • Transport fatty acids, hormones and vitamins • Regulate osmotic pressure and blood volume • Fight viral and bacterial infections • Aid in blood clotting
TYPES OF BLOOD VESSELS • Arteries • Large and thick-walled • Carry blood from the heart to the rest of the body
TYPES OF BLOOD VESSELS • Veins • Smaller than arteries and not as thick-walled • Carry blood from the rest of the body back to the heart
TYPES OF BLOOD VESSELS • Capillaries • Tiny blood vessels with walls that are only one cell thick • Oxygen and nutrient absorption take place in the capillaries • Also move CO2 and waste products into the blood from cells
Blood Flow Through the Heart • Oxygen poor- 1.) Superior and inferior vena cava 2.) Right Atrium 3.) Right Ventricle 4.) Lungs • Oxygen rich- 5.) Left Atrium 6.) Left Ventricle 7.) Aorta 8.) Body
Blood Flow Through the Body • Pulmonary circulation • Right side of the heart pumps blood from the heart to the lungs • Systemic circulation • Left side of the heart receives blood from the lungs and pumps it to the rest of the body
Closed vs. Open Circulation • Closed circulation – blood is contained in a system of vessels and forced through them by a heart or heart-like organ • Open circulation – blood is partially contained in a system of vessels; a heart or heart-like pump pushes the blood though spongy tissues
Function of the Excretory System • Maintains homeostasis in the body by removing waste products from the cells and expelling them from the body • Single-celled organisms can use active transport or diffusion • Multicellular organisms must have a complete system
Parts of the Excretory System • Kidneys : • remove waste products from the blood • maintain blood pH • regulates total blood volume by controlling water content in blood • Ureters • Urinary Bladder • Urethra • Skin – releases excess salts and water through pores • Lungs – remove excess carbon dioxide from the blood
Kidney Structure • 2 regions of kidney • Renal cortex-outer region • Renal medulla-inner region • Nephrons • Functional units • (~1 million each kidney)
Step 1: Filtration Materials filtered from the blood by the nephron are called filtrate • Water • Salts • Glucose • Amino acids • Urea (the waste product of amino acid breakdown)
Step 2: Re-absorption • Amino acids, fat, glucose and most water - returned to the blood. • Urine - urea, excess salts and water; stays in the nephron
Step 3: excretion Flow of Urine: Nephron Ureters Urinary bladder Urethra • Average bladder capacity is 500 ml (16 oz) • ~48 gallons of filtrate are processed each day; 1% is excreted as urine (~ .5 gallon)
Homeostasis by machine • Dialysis - blood is passed through a filtration system other than the kidneys and returned to the body Hemodialysis - machine Peritoneal dialysis