Excretory System

Essential question: What is the process of excretion? Excretion-process of ridding the body of metabolic wastes. Types of Waste Products:  Breathing  Carbon dioxide and Water  Dehydration Synthesis  Water  Metabolic Activities  Mineral Salts  Protein Metabolism  Nitrogenous Wastes

Essential question: What are nitrogenous wastes? Nitrogenous Wastes: a. Result from breakdown of amino acids (contain nitrogen). b. Includes ammonia(NH3). b. Includes ammonia(NH3). NH3-->Urea (soluble in water) NH3-->Urea (soluble in water) Urea + water-->Urine Urea + water-->Urine NH3 is toxic to cells NH3 is toxic to cells

Grasshopper and Uric Acid

Essential Questions: What are the structures involved in excretion? Structures Involved in Excretion:  Lungs  Liver  Skin  Kidneys/Ureters  Urinary Bladder/ Urethra Urethra

Lungs-excrete CO2 and H2O vapor by diffusion.

Liver: Removes worn out RBC and excess A.A. Turns nitrogenous wastes into urea that then it adds to the blood. Detoxification-removal of poisons. Ex. Alcohol Stores glucose as glycogen. Helps to maintain the water balance between blood and intracellular fluid.

Essential question: What are the parts of the skin and how do they work together to maintain homeostasis? Skin: Functions: 1. Protects underlying tissue. 2. Helps to regulate body temperature. 3. Organ of excretion (urea, water, salt).

Parts of the Skin: Two Separate layers-1. Epidermis 2. Dermis Epidermis: Outer layer Thin layer Prevents bacteria and harmful chemicals from entering the body. prevents water from the leaving the body. Beneath this layer are cells that produce pigments.

Dermis: Inner layer. Inner layer. Contains sensory nerve endings that detect temperature and touch. Contains sensory nerve endings that detect temperature and touch. Contains hairs and capillaries to regulate body temperature. Contains hairs and capillaries to regulate body temperature. Muscles attached at bottom ends of hair-response to fear (goose bumps). Muscles attached at bottom ends of hair-response to fear (goose bumps). Contains sebaceous glands- release oil. Contains sebaceous glands- release oil. Contain sweat glands-urea. Contain sweat glands-urea. Contain fat tissue-insulation Contain fat tissue-insulation

Essential Questions: What is function of the kidneys? What structures makes up the kidneys? Functions of the kidneys: Maintain water balance. Removal of metabolic wastes. Regulating pH balance. The kidneys do all of these functions by filtration and absorption.

Kidneys: Bean shaped. Bean shaped. Located in rear of abdominal cavity.Located in rear of abdominal cavity. Compose of three different layers:Compose of three different layers: cortex-outer layer cortex-outer layer medulla-inner layer pelvis- sac like chamber medulla-inner layer pelvis- sac like chamber Contains one million nephrons (in each kidney)Contains one million nephrons (in each kidney) Nephron-basic unit of function in the kidney.. Nephron-basic unit of function in the kidney..

Essential question: What role do the nephrons play in the process of excretion?

Essential Question: What is the process of excretion? Process of Excretion: Process of Excretion: Urine collects in the kidneys’ pelvis. Drips down the ureters. Stored in the urinary bladder. Excreted through the urethra.

Diseases Associated with the Excretory System: Nephritis: Inflammation of kidneys. Inflammation of kidneys. Occurs most often in children and adolescents. Occurs most often in children and adolescents. Caused by bacterial infection. Caused by bacterial infection. Can lead to kidney failure. Can lead to kidney failure.

Essential Questions: What are kidney stones? What is the treatment for kidney stones? Kidney Stones: Build up of Ca in Kidneys. Cause is unknown. Surgery or shock waves to break up stones.

Gout: Occurs primarily in men. High levels of uric acid (nitrogenous waste). Forms sharp crystals. Produces severe pain in the joints. Ex. Big toe Need to drink lots of water, eat a special diet and take medication.

Cirrhosis Scarring and eventual death of liver cells. Cause by products of alcohol break down. 9th leading cause of death in US.

Essential Question: What regulates the excretory system? Regulation of Excretory System: The excretory system is regulated by the nervous and endocrine system. The excretory system is regulated by the nervous and endocrine system. 1. Sweating after exercise reduces the volume of water in blood. Stimulates the hypothalamus (in the brain) to send messages to the pituitary gland to secrete Antidiuretic Hormone (ADH). ADH causes the kidneys to increase their re-absorption of water from urine. Thus the blood volume returns to normal. Urine becomes darker and shows that the body is automatically readjusting itself by not releasing much water. 1. Sweating after exercise reduces the volume of water in blood. Stimulates the hypothalamus (in the brain) to send messages to the pituitary gland to secrete Antidiuretic Hormone (ADH). ADH causes the kidneys to increase their re-absorption of water from urine. Thus the blood volume returns to normal. Urine becomes darker and shows that the body is automatically readjusting itself by not releasing much water. 2. When Na level rise in the body, the adrenal glands (top of the kidneys) secrete less aldosterone (hormone) causes the nephrons to reabsorb salt (NaCl). If the body allowed all the salt to be reabsorbed it could lead to kidney failure. 2. When Na level rise in the body, the adrenal glands (top of the kidneys) secrete less aldosterone (hormone) causes the nephrons to reabsorb salt (NaCl). If the body allowed all the salt to be reabsorbed it could lead to kidney failure.