Excretory system

Cliffs page 203-206

Textbook diagrams

Study guide questions

What is the function of the excretory system?

Maintains homeostasis by disposing metabolic wastes and control body fluid composition

Describe 2 specific examples of osmoregulation in fish.

Osmoregulation: the general process by which animals control solute concentrations and balance water gain and loss

Salt water fishes: Gain water and salt ion through drinking seawater or from food, Excretion of salt ions from gills, Osmotic water loss through gills and other parts of body surface, Excretion of salt ions and small amounts of water in scanty urine from kidneys

Fresh water fishes: Uptake of water and some ions in food, Uptake of salt ions by gills, Osmotic water gain through gills and other parts of body surface, Excretion of large amounts of water in dilute urine from kidneys

There is diversity in the excretory mechanisms of living thing. Describe each and include an example.

Contractile vacuoles:

Flame cells

Nephridia

Malpighian tubules

Mammalian kidney

Describe the functional unit of the human kidney

Nephron is the basic structural and functional unit of the kidney. Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine. A nephron eliminates wastes from the body, regulates blood volume and pressure, controls levels of electrolytes and metabolites, and regulates blood pH. Its functions are vital to life and are regulated by the endocrine system by hormones such as antidiuretic hormone, aldosterone, and parathyroid hormone. Each nephron is composed of an initial filtering component (the "renal corpuscle") and a tubule specialized for reabsorption and secretion (the "renal tubule"). The renal corpuscle