BIOL 1108 1nd Edition Lecture 16Outline of Last Lecture I. Learning Objectives II. In The NewsIII. OsmoregulationIV. ExcretionV. Evolutionary Structural Variations Outline of Current Lecture I. Learning Objectives II. Excretory System Function Overview III. FunctionsIV. Blood Filtrate to Urine V. Regulation Current LectureI. Learning Objectives 1. Be able to:- Describe the structures and process of blood filtration to urine formation in kidney nephrons- Describe a kidney regulation processII. Excretory System Function Overviewa. Filtration- Hydrostatic pressure (blood pressure) pushes bodily fluids (blood, hemolymph, coelomic) in contact with a selectively permeable membrane (transport epithelium) - Diffusion depends on the concentration of solutes b. Re-absorptionThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Recovering useful molecules and water from the filtrate (water and solutes) and then returning it to the bodily fluids.c. Secretion - The discharge of wastes from the bodily fluids to the filtrated. Excretion- Filtrate with nitrogenous wastes and is released from the body as urineIII. Functions1. Excretion of waste (unwanted products of metabolism)a. Filtration starts at the Bowman’s Capsule, where there is a lot of pressure2. Salt and water balance: osmoregulationIV. Blood Filtrate to Urine a. Filtration of blood flows to the Bowman’s Capsule as active transport (lots of energy)b. In the proximal tubule, the filtrate goes through reabsorption before heading down the Loop of Henlei. The longer the loop the more the organism can conserve waterc. The descending part of the Loop of Henle contains many aquaporins in order for water to reabsorb back into the kidneys (more hyperosmotic).d. As the loop ascends, salt/ solutes are being pulled out of the filtrate through passive transport. i. This part of the Loop of Henle is impermeable to water and contains no aquaporins ii. The higher the filtrate travels the more diluted it gets.e. At the distal tubule, the diluted filtrate controls body pH through reabsorption (active transport)f. Lastly, while the filtrate travels down the collecting duct there is more water reabsorption and active removal of salt - Osmolarity gradient in each kidney increases in intestinal fluid - 300 mOsm/L= blood- 1200 mOsm/L= urine- 1000 mOsm/L= ocean waterV. Regulationa. Pituitary gland- produces endocrine hormones to signal out kidneysi. Releases Antidiuretic hormone to reduce urination if water in blood is lowb. Hypothalamus- regulates water content in
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