Excretory System Adam Amy Karlene and Yifan S

Excretory System Adam, Amy, Karlene, and Yifan S

Introduction S http: //www. youtube. com/watch? v=gu. Oqyi 5 l. UQQ (1: 46 -4: 36) S Regulates bodily fluids, excreting and recycling waste S Main organs: kidneys, ureters, bladder and urethra S Disorders of the excretory system

Excretion S After metabolic activities (energy release, maintenance, repair) results in waste S Separating the needed and the unneeded or no longer needed S Skin, respiratory system, digestive system, excretory system

Overall Major Functions Excretion of waste Secretion of hormones Major functions of excretory system p. H control Maintenanc e of water and salt

Functions: Excretion of Metabolic Waste S The average person urinates 3000 a year S Bladder can hold 16 -24 ounces of urine S Nitrogenous waste S Urea makes up the majority of this waste

Functions: Maintenance of Water-Salt Balance S Maintain balance with water and salt in blood S Regulating blood pressure S Balance between potassium, bicarbonate and calcium S Cells need to stay in an isotonic solution

Functions: Maintenance of Acid-Base Balance S Buffer for blood S Blood p. H: 7. 4 S Urine is usually a p. H of 6 S Maintenance of alkaline reserve

Functions: Secretion of Hormones S Aids endocrine system in hormonal secretion S Calcitriol: Promotes calcium absorption S Erythropoiten: Production of red blood cells S Renin

Major Organs Urinary bladder Urethra Kidney (Nephrons)

Organs S Kidneys: Lower back, filters waste from blood, functions named above S Ureter: Muscular tubes that carry urine S Urinary Bladder: Urine is stored S Urethra: Tube that urine is secreted from

Kidney: Introduction

Kidney: Pathway Nephron

Kidney: Pathway S Filter S Tubule S Duct

Kidney: Filter S Renal artery enters Bowman’s capsule; glomerulus S Walls of glomerulus are impermeable to large molecules S pressurized blood aids filtration S Small molecules are permeable S The result is known as filtrate

Kidney: Tubule S Bowman’s capsule is connected to a looped tubule S Divided into three parts S Proximal convoluted tubule S Loop of Henle S Distal convoluted tubule S Used by each nephron for reabsorption

Kidney: Tubule S Proximal convoluted tubule S Uses ATP for active transport S Drives sodium ions, glucose, and other solutes back into the blood S Water follows these substances into the blood by osmosis

Kidney: Tubule S Loop of Henle

Kidney: Tubule S Loop of Henle S Descending limb extends from within the renal cortex into the renal medulla; extremely salty S Permeable to water; water flows back into blood S Ascending limb is impermeable to water and slightly permeable to solutes S Na+ diffuses out of the tubule and into nearby blood vessels

Kidney: Tubule S In the thick-walled section, more Na+ is removed by active transport (uses ATP) S Replenishes medulla’s salt S Makes the filtrate less concentrated than surrounding cortex tissue

Kidney: Tubule 1. Medulla is salty 4. Increases osmolarity for future filtrate 2. Reabsorption of water causes salt concentration to decrease 3. ATP is used to actively reabsorb sodium ions

Kidney: Tubule S Loop of Henle

Kidney: Tubule S Distal convoluted tubule S Active reabsorption depends on the needs of the body (sodium ions) S Passive reabsorption of negative ions occurs by electrical attraction (chloride) S Potassium ions and hydrogen ions are actively secreted by the body

Kidney: Duct S Tubule empties into a large pipe-like channel called a collecting duct S Lowers back into the medulla; reabsorbs water S The size of the pores depends on signals from the brain S The result can now be called urine S Reabsorbed substances are returned to the body

The roles of ADH and aldosterone in regulating water balance S

Water Balance: Pituitary Gland S The pituitary gland is a gland at the base of the brain that sends signals to other glands and organs such as the thyroid gland, adrenal glands, ovaries, and testes S Directs them to produce certain hormones S Produces LD, ADH, FSH, and growth hormones

Water Balance: The Brain

Water Balance: Aldosterone S Aldosterone is a hormone that is produced by the adrenal glands S It works primarily on kidney (renal) cells to help maintain the balance of fluids and electrolytes in our bodies S It mainly works to control reabsorption of sodium and chloride and secretion of potassium and hydrogen

Water Balance: Aldosterone S Pathway: S The role of aldosterone in sodium and water balance is to regulate fluid and electrolyte balance S When sodium and plasma volume is decreased, it triggers the synthesis and secretion of aldosterone S When sodium and plasma volume return to normal levels, aldosterone secretion is reduced

Water Balance: Adrenal Gland

Water Balance: ADH S A hormone produced in the hypothalamus and secreted by the posterior pituitary gland S ADH stimulates reabsorption of water through the distal tubules and collecting ducts of the kidney, resulting in less water being excreted in the urine, thus conserving water

Water Balance: ADH S Pathway: S Part of the brain, the hypothalamus, detects that there is not enough water in the blood. The hypothalamus sends a message to the pituitary gland, which releases ADH travels from brain to the kidney and causes the kidneys to absorb more water and concentrate the urine. A lack of ADH results in increased urine volume and increased urination, a condition called diabetes insipidis.

Water Balance: ADH S ADH: antidiuretic hormone S Pathway: S Part of the brain, the hypothalamus, detects that there is not enough water in the blood S The hypothalamus sends a message to the pituitary gland, which releases ADH S ADH travels from brain to the kidney and causes the kidneys to absorb more water and concentrate the urine S A lack of ADH results in increased urine volume and increased urination, a condition called diabetes insipidis.

Water Balance: Deficit

Water Balance: Surplus

Water Balance: End of Cycle

Regulation of Blood p. H Maintaining Blood p. H in the Excretory System S

Blood p. H: Introduction S The normal p. H of blood is around 7. 4 S Allows our enzymes to function optimally S Failing to maintain homeostasis causes our blood p. H to either increase or decrease S This increase/decrease can result in serious medical condition

Blood p. H: Introduction S One way our blood p. H can change in based on the foods/liquids we consume S Blood p. H can also changed from metabolic processes S Three main homeostatic mechanisms used to maintain blood p. H S Acid-Base Buffer System S Respiratory Centre S Kidney Function

Blood p. H: Acid-Base Buffer S Buffers blood; prevents changes in p. H S Takes up extra H+ ions of extra OH- ions that enter the blood S One of the most important buffer system involves the use of carbonic acid and bicarbonate ions

Blood p. H: Acid-Base Buffer S The system reacts differently depending on the presence of extra hydrogen ions of extra hydroxide ions S If H+ is added, the reaction that occurs is: S H+ + HCO 3 - H 2 C 03 S When OH- ions are added to blood: S OH- + H 2 CO 3 HCO 3 - + H 2 O

Blood p. H: Acid-Base Buffer S In the first reaction, the bicarbonate ion takes up excess hydrogen ion, in order to form carbonic acid S In the second reaction, water is produced S Water will help maintain the blood p. H, since water is neutral S These reactions temporarily prevent major changes in p. H

Blood p. H: Respiratory Centre S The hydrogen ion concentration is raised, the respiratory centre (in the medulla oblongata) increases breathing rate S It does this through specific signals that ensure our breathing muscles contract and relax regularly S Doing this causes the body to get rid of hydrogen ions S H+ + HCO 3 - H 2 CO 3 H 2 O + CO 2

Blood p. H: Respiratory Centre S When the reaction moves from carbon dioxide to hydrogen, the blood p. H decreases and increases the other way S Increasing breathing causes carbon dioxide to be generated more quickly, decreasing the number of hydrogen ions S It is vital to have the correct proportion of carbonic acid to bicarbonate ions in blood S Breathing causes a readjustment so the proportion is + -

Blood p. H: Kidneys S The first two mechanisms are aided by powerful actions of the kidneys S Only the kidneys are able to rid the body of a vast range of acidic and basic substances S Kidneys are slower acting, but have a more powerful effect S It is possible to urinate the excess acidic H+ ions or basic HCO 3 - ions in order to raise or lower blood p. H

Blood p. H: Kidneys S Imagine the kidneys as releasing H+ and reabsorbing HCO 3 - in order to maintain homeostasis S If blood is too acidic, H+ is released and HCO 3 - is absorbed S However, if blood is basic, neither is used S Another way of buffering is by using ammonia S Removes hydrogen ions and adds in bicarbonate ions S NH 3 + H+ NH 4+

Blood p. H: Kidneys S Ammonia is produced in the tubule cells through the breakdown of amino acids S Ammonia works to produce ammonium ions S For every ammonium ion that is produced, a new HCO 3− is made

Blood p. H: Summary S There are three mechanisms used to maintain homeostasis, in terms of blood p. H S Acid-Base Buffer System S Respiratory Centre S Kidney Function S Each one has a unique way of doing so S All three have advantages and disadvantages that go along with them

Dialysis: Introduction S What is dialysis? S Procedure that removes wastes and excess fluid from the blood when kidney function is lost due to renal failure S Why is dialysis needed? S Hyperkalemia S High potassium S Hyperphosphatemia S High phosphate S Uremia S Edema

Dialysis: Two Types

Conclusion S The human excretory system is responsible for removing liquid waste from the body S The excretory system also regulates the acid-base balance and water-salt balance of the blood and secretes some hormones like ADH S The kidneys are composed of millions of functional units called nephrons that filter the waste from the blood and produce urine. S Dialysis is the procedure that removes wastes and excess fluid from the blood when kidney function is loss due to renal failure

Question #1 S What is urine?

Answer S Filtrate of the nephron upon leaving the collecting duct; exits the body through the urethra

Question #2 S What is a function in the excretory system that is involved in regulating blood pressure and the appropriate potassium, bicarbonate, and calcium levels in blood?

Answer Maintenance of Water-Salt Balance

Question #3 S What is the role of ADH?

Answer S Stimulates reabsorption of water through the distal tubules and collecting ducts of the kidney S Results in less water being excreted in urine

Question #4 S What is the pituitary gland?

Answer S Gland at the base of the brain S Send signals to other glands and organs to produce certain hormones

Question #5 S What is this picture showing?

Answer S Respiratory Centre Equation

Question #6 S What is this picture showing?

Answer S The process of how the kidneys maintain the p. H of blood

Question #7 S Name the 2 types of dialysis. What are their differences?

Answer S Hemodialysis S Removing wastes and excess fluids from the blood by an external devices connected to an artery and a vein in a person’s arm. S For acute renal failure S Peritoneal Dialysis S Removing wastes and excess fluids from the blood by inserting a catheter into the abdominal cavity. S For Chronic renal Failure

Question #8 S What type of dialysis is this picture showing?

Answer S Hemodialysis

References S http: //www. nhlbi. nih. gov/health//dci/Diseases/hlw_con trols. html S http: //h 2 g 2. com/approved_entry/A 8819652 S https: //www. inkling. com/read/textbook-of-medical- physiology-guyton-hall-12 th/chapter-30/combination-ofexcess-h-with S Grade 12 Biology Textbook

S Carter-Edwards, T. , Gerards, S. , Gibbons, K. , Mc. Callum, S. , Noble, R. , Parrington, J. , . . . Whyte-Smith, A. (2011). Biology 12. Canada, Mc. Graw-Hill Ryerson, pp. 444 -462. S De. Bruyne, L. K. , Pinna, K. , & Whitney, E. (2012). Nutrition & Diet Therapy (8 thed. ). United States, Wadsworth, Cengage Learning, pp 595 -607.

S http: //www. youtube. com/watch? v=cc 8 s. Uv 2 Sua. Y S http: //www. youtube. com/watch? v=Wtr. Yotj. Yvt. U S http: //www. webmd. com/a-to-z-guides/function-kidneys S http: //science. howstuffworks. com/life/human- biology/kidney 1. htm