Water Balance Osmoregulation What is it Osmosis Osmosis

Water Balance

Osmoregulation • What is it?

Osmosis

Osmosis • Osmotic pressure: • Hyperosmotic: • Hypoosmotic:

Osmotic pressure • What is the desirable condition in terms of osmotic pressure? • Isoosmotic: • Why?

Osmotic pressure

The Excretory System

Purpose 1. 2.

Kidneys • Major organ of excretory system • Roles: 1. 2. 3. 4. 5.

Kidney Blood flow Blood enters the kidney through the _____ which stems from the _____. Filtered blood exits the kidney through the _____ which emptied into the _____.

Kidney Structure Blood is filtered by specialized tubules called _______. About a million make up the kidney. Collect ______ and ______ to be excreted. Collection occurs over a long tube pathway, allowing for maximum control of water and solute concentrations.

Nephron Structure

Nephron processes • Filtering • Reabsorption • Secretion

Nephron filtering • Blood is brought to the nephron by the ________ • At nephron, blood flows through a mass of capillaries called the ______ where filtering occurs • Filtered blood leaves through _______ and moves towards rest of nephron for next stages

Nephron filtering • Bowman’s capsule water Na+ H+ Clglucose amino acids vitamins minerals urea uric acid

Nephron reabsorption and secretion • Proximal tubule HCO 3 -, K+ Na+, Cl. H 2 O amino acids glucose vitamins H+ NH 3

Nephron reabsorption and secretion • Loop of Henle – descending branch H 2 O

Nephron reabsorption and secretion • Loop of Henle – ascending branch Na. Cl

Nephron reabsorption and secretion • Distal tubule HCO 3 Na+, Cl. H 2 O H+ NH 3 K+

Nephron reabsorption and secretion • Collecting duct Na. Cl urea water

Nephron Review