Download to read offline
More Related Content
Similar to Invertebrate and Vertebrate Excretory System.pptx
Invertebrate and Vertebrate Excretory System.pptx
- 1.
- 34. The nephron consistsof a cup-shaped capsule containing capillaries and the glomerulus, and a long renal tube. Blood flows into the kidney through the renal artery, which branches into capillaries associated with the glomerulus. Arterial pressure causes water and solutes from the blood to filter into the capsule. Fluid flows through the proximal tubule, which include the loop of Henle, and then into the distal tubule. The distal tubule empties into a collecting duct.
- 35. The nephron hasthree functions: Glomerular filtration of water and solutes from the blood. Tubular reabsorption of water and conserved molecules back into the blood. Tubular secretion of ions and other waste products from surrounding capillaries into the distal tubule. Nephrons filter 125 ml of body fluid per minute; filtering the entire body fluid component 16 times each day. In a 24 hour period nephrons produce 180 liters of filtrate, of which 178.5 liters are reabsorbed. The remaining 1.5 liters forms urine.
- 37. Urine Production: Filtration inthe glomerulus and nephron capsule. Reabsorption in the proximal tubule. Tubular secretion in the Loop of Henle.
- 38. Components of TheNephron: Glomerulus: mechanically filters blood Bowman's Capsule: mechanically filters blood Proximal Convoluted Tubule: Reabsorbs 75% of the water, salts, glucose, and amino acids Loop of Henle: Countercurrent exchange, which maintains the concentration gradient Distal Convoluted Tubule: Tubular secretion of H ions, potassium, and certain drugs.
- 39. Kidney Stones: In somecases, excess wastes crystallize as kidney stones. They grow and can become a painful irritant that may require surgery or ultrasound treatments.
- 40. Kidneys perform anumber of homeostatic functions: Maintain volume of extracellular fluid Maintain ionic balance in extracellular fluid Maintain pH and osmotic concentration of the extracellular fluid. Excrete toxic metabolic by-products such as urea, ammonia, and uric acid.
- 41. Hormone Control ofWater and Salt Water reabsorption is controlled by the antidiuretic hormone (ADH) in negative feedback. ADH is released from the pituitary gland in the brain. Dropping levels of fluid in the blood signal the hypothalamus to cause the pituitary to release ADH into the blood. ADH acts to increase water absorption in the kidneys. This puts more water back in the blood, increasing the concentration of the urine. When too much fluid is present in the blood, sensors in the heart signal the hypothalamus to cause a reduction of the amounts of ADH in the blood.
- 42. Aldosterone, a hormonesecreted by the kidneys, regulates the transfer of sodium from the nephron to the blood. When sodium levels in the blood fall, aldosterone is released into the blood, causing more sodium to pass from the nephron to the blood. This causes water to flow into the blood by osmosis. Renin is released into the blood to control aldosterone.
- 44. Disruption of KidneyFunction Infection, environmental toxins such as mercury, and genetic disease can have devastating results by causing disruption of kidney function. Many kidney problems can be treated by dialysis, where a machine acts as a kidney. Kidney transplants are an alternative to dialysis.
- 61.