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Regents Living Environment Mr. Skolnick

Regents Living Environment Mr. Skolnick. Gas Exchange: Chapter 11 Excretion: Chapter 12. Gas Exchange. Gas Exchange: the general back-and-forth movement of carbon dioxide and oxygen between organisms and their environment.

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Regents Living Environment Mr. Skolnick

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  1. Regents Living EnvironmentMr. Skolnick Gas Exchange: Chapter 11 Excretion: Chapter 12

  2. Gas Exchange • Gas Exchange:the general back-and-forth movement of carbon dioxide and oxygen between organisms and their environment. • In order for a gas to pass into or out of a cell, it must be dissolved in a liquid. • Simple organisms live in water, in damp areas on land, or within the moist environment of a host. • To accommodate gas exchange among more complex forms of life, certain body areas specialized in gas exchange have evolved. • Body tissues in gas exchange areas are moist, have large surface areas, and have very thin membranes so gases can easily cross over. • Because these tissues are so delicate, the bodies of most large, complex animals have evolved structures that shield the gas exchange areas from possible injury. • Respiration: in complex animals, the intake of oxygen and the discharge of carbon dioxide.

  3. Respiratory System in Humans: Lungs Nasal chamber Epiglottis Trachea Bronchi Bronchioles Alveoli

  4. Breathing: movement of air (inhale, exhale). About 12-16X/minute. An increase in CO2 concentration stimulates a increase in the breathing rate. How do you breathe? Movement of the ribcage and diaphragm. Air pressure decrease: air rushes in. Air pressure increase: air rushes out. Control of Breathing

  5. Carbon monoxide CO is produced from burning fossil fuels. CO is picked up by RBCs faster than O2→ suffocation. A body is found at a fire scene but investigators are not sure whether the victim was alive when the fire began. How can measuring the level of carbon monoxide in the victim’s blood help determine this? The presence of high levels of carbon monoxide in the blood would prove that the victim breathed the combustion products of the fire and was therefore alive when the fire began. Low levels of carbon monoxide would suggest that the victim was dead before the fire started. Problems of the Respiratory System

  6. Problems of the Respiratory System • Pneumonia • Infection of the lungs → alveoli fill with fluid, and gas exchange is prevented.

  7. Problems of the Respiratory System • Emphysema • Walls of the alveoli become damaged due to smoking, and don’t function properly. • Lung Cancer • Uncontrolled cell growth in the lung tissue → tumors.

  8. Problems of the Respiratory System • Asthma • An allergic reaction → breathing difficulties. • Asthma attack → bronchioles go into spasms, squeezing the air passages. • Bronchitis • Linings of the bronchiole tubes become irritated and swollen. Passageways to alveoli may swell & clog with mucus.

  9. As an organism carries out its life processes, waste products build up in the body fluids. These metabolic wastes must be removed, or the organism may die. Excretion: the process by which these wastes are removed from an organism. In humans and other complex animals, the excretory organs are the lungs, kidneys, liver, and skin. Metabolic wastes: CO2, water, certain nitrogen compounds, and mineral salts. CO2 and water are formed during cellular respiration. Nitrogen compounds: ammonia, urea, and uric acid are produced during the breakdown of amino acids (deamination). Mineral salts build up during metabolism. Elimination (or defecation) is not excretion: removal of unabsorbed or undigested food from the digestive tract. Excretion

  10. The Human Excretory System • The liver, kidneys, lungs, and skin

  11. The liver removes harmful substances, such as bacteria, certain drugs, and hormones, from the blood. The liver detoxifies the blood: these substances are changed into less poisonous forms, which are returned to the bloodstream and excreted from the body by the kidneys. Cirrhosis:liver damage due to overloading with harmful materials over time. causes the death of over 13,000 Americans per year. The Role of the Liver in Excretion

  12. Excretion of bile: When bile is not excreted properly, its metabolic wastes are reabsorbed into the blood, resulting in jaundice. Formation of urea: Excess amino acids are broken down in the liver: each amino group (NH2) is changed into ammonia (NH3). Ammonia is changed into the less toxic urea, which is returned to the bloodstream. The kidneys filter urea from the blood. The Role of the Liver in Excretion

  13. Consists of the: kidneys, ureters, bladder, and the urethra. Kidneys: main excretory organs. 2 fist-sized, bean-shaped structures. Nephrons: filter unit of the kidney (1 million per kidney). Renal artery: directs blood into a kidney. Renal vein: returns purified blood to general circulation. Urine: waste filtered by the kidney – urea, salts, and water. Ureter: tube carrying urine from the kidney to the bladder. Urinary bladder: stores urine. Urethra: passes urine out of the body. The Urinary System

  14. Nephron: Bowman’s capsule: cup-shaped structure of the nephron. Glomerulus: mass of capillaries in the center of each capsule. Two Processes: 1. Filtration: Water, urea, glucose, amino acids, and various salts pass from the Glomerulus into the Bowman’s capsule (blood cells and blood proteins are too large to pass through). About 1-1.5 liters of urine are formed from this filtrate per day. 2. Reabsorption: Various important substances are returned to the blood (99% of the water, all of the glucose and amino acids, and many of the salts). What remains is urine, which is sent to the collecting ducts, then to the ureters, then to the bladder. The Kidneys

  15. The lungs excrete carbon dioxide and water. The Lungs

  16. Skin, hair, and nails. Skin is the largest organ in the body! Skin color is due to melanin, which absorbs UV radiation from the sun. Epidermis: outer layers die and fall off in sheets. Keratin is a waterproofing protein. Dermis: thicker layer – has blood vessels, nerves, oil and sweat glands, and hair follicles. Layer of fat underneath. Purposes: Keep moisture in the body, and foreign particles, pathogens out. Sense of touch. Regulate body temp – sweat is water (99%), urea, salts. Removal of excess body heat – increased blood flow. The Integumentary System

  17. Gout: crystals of uric acid in joints – arthritis. Kidney Stones: crystallized substances in kidney or urinary tract – must pass with urine, or be shattered with sound waves. Kidney Failure: dialysis machine. Cirrhosis & Jaundice: Excretory System Problems

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