Objective 1 List the functions of the urinary system and explain how they contribute to homeostasis. Unit 1 - Objective 1

Functions of the Urinary System Filtration of the blood – Occurs in the glomerulus of the kidney nephron – Contributes to homeostasis by removing toxins or waste Unit 1 - Objective 1

Functions of the Urinary System Reabsorption of vital nutrients, ions and water – Occurs in most parts of the kidney nephron – Contributes to homeostasis by conserving important materials Unit 1 - Objective 1

Functions of the Urinary System Secretion of excess materials – Assists filtration in removing material from the blood – Contributes to homeostasis by preventing a build-up of certain materials in the body such as drugs, waste,etc. Unit 1 - Objective 1

Functions of the Urinary System Activation of Vitamin D –Vitamin D made in the skin is converted to Vitamin D3 by the kidney –Active Vitamin D (D3) assists homeostasis by increasing calcium absorption from the digestive tract Unit 1 - Objective 1

Functions of the Urinary System Release of Renin by the kidney –Renin stimulates the formation of a powerful vasoconstrictor called Angiotensin II –Angiotensin II assists homeostasis by causing vasoconstriction which increases blood pressure Unit 1 - Objective 1

Functions of the Urinary System Secretion of H (+1) and reabsorption of HCO3 (-1) – Eliminates excess hydrogen ions and conserves buffer material such as bicarbonate –Contributes to homeostasis by controlling acid/base conditions in body fluids Unit 1 - Objective 1

Objective 2 Given a diagram of the Urinary System, you will recognize and label the following parts: kidney, ureters, bladder, urethra, internal and external sphincters. Unit 1 - Objective 2

Figure 18.1

Urinary System Internal urethral sphincter External Urethral Sphincter Male Sphincters Female Sphincters

Objective 3 Given a diagram of the kidney you will label and give the functions of the following structures: renal vein, renal artery, capsule, cortex, medulla, pyramids, renal papilla, calyx, pelvis, ureter, renal column and nephron Unit 1 - Objective 3

Kidney Diagram

Functions of Kidney Structures Examine the kidney structures in the following slides and note the particular functions. Unit 1 - Objective 3

Functions of Kidney Structures The Renal Artery – Transports oxygenated blood from the heart and aorta to the kidney for filtration Unit 1 - Objective 3

Functions of Kidney Structures Renal Vein – Transports filtered and deoxygenated blood from the kidney to the posterior vena cava and then the heart Unit 1 - Objective 3

Functions of Kidney Structures Renal Column –A passageway located between the renal pyramids found in the medulla and used as a space for blood vessels Unit 1 - Objective 3

Functions of Kidney Structures Nephron –The physiological unit of the kidney used for filtration of blood and reabsorption and secretion of materials Unit 1 - Objective 3

Functions of Kidney Structures Capsule –The outer membrane that encloses, supports and protects the kidney Unit 1 - Objective 3

Functions of Kidney Structures Cortex –The outer layer of the kidney that contains most of the nephron; main site for filtration, reabsorption and secretion Unit 1 - Objective 3

Functions of Kidney Structures Medulla – inner core of the kidney that contains the pyramids, columns, papillae, calyces, pelvis and parts of the nephron not located in the cortex; used for salt, water and urea absorption Unit 1 - Objective 3

Functions of Kidney Structures Renal Pyramids –Triangular shaped units in the medulla that house the loops of Henle and collecting ducts of the nephron; site for the counter- current system that concentrates salt and conserves water and urea Unit 1 - Objective 3

Functions of Kidney Structures Renal Papilla –The tip of the renal pyramid that releases urine into a calyx Unit 1 - Objective 3

Functions of Kidney Structures Calyx – A collecting sac surrounding the renal papilla that transports urine from the papilla to the renal pelvis Unit 1 - Objective 3

Functions of Kidney Structures Renal Pelvis – Collects urine from all of the calyces in the kidney Unit 1 - Objective 3

Functions of Kidney Structures Ureter – Transports urine from the renal pelvis to the bladder Unit 1 - Objective 3

Objective 4 Given a diagram of a Nephron you will label and give the functions of the structures : afferent arteriole, efferent arteriole, glomerulus, Bowman’s capsule, proximal convoluted tubule, decending limb and ascending limbs of the loop of Henle, vasa recta, distal convoluted tubule, peritubular capillaries and the collecting duct. Unit 1 - Objective 4

Nephron

Functions of Nephron Structures AfferentArteriole – Transports arterial blood to the glomerulus for filtration Unit 1 - Objective 4

Functions of Nephron Structures Efferent Arteriole – Transports filtered blood from the glomerulus, through the peritubular capillaries and the vasa recta, and to the kidney venous system Unit 1 - Objective 4

Functions of Nephron Structures Glomerulus –The site for blood filtration –operates as a nonspecific filter; in that, it will remove both useful and non-useful material –the product of the glomerulus is called filtrate Unit 1 - Objective 4

Functions of Nephron Structures Bowman’s Capsule –A sac that encloses Bowman’s Capsule and transfers filtrate from the glomerulus to the Proximal Convoluted Tubule (PCT ) Unit 1 - Objective 4

Functions of Nephron Structures Proximal Convoluted Tubule (PCT) –A thick, constantly actively segment of the nephron that reabsorbs most of the useful substances of the filtrate : sodium (65%), water (65%), bicarbonate (90%), chloride (50%), glucose (nearly 100%!), etc. – The primary site for secretion (elimination) of drugs, waste and hydrogen ions Unit 1 - Objective 4

Functions of Nephron Structures Decending Limb of the Loop of Henle –A part of the counter current multiplier –freely permeable to water and relatively impermeable to solutes (salt particles) –receives filtrate from the PCT, allows water to be absorbed and sends “salty”filtrate on the the next segment. “Saves water and passes the salt” Unit 1 - Objective 4

Functions of Nephron Structures Ascending Limb of the Loop of Henle –a part of the counter current multiplier – impermeable to water and actively transports (reabsorbs) salt (NaCl) to the interstitial fluid of the pyramids in the medulla. “ Saves salt and passes the water.” –the passing filtrate becomes dilute and the interstitium becomes hyperosmotic Unit 1 - Objective 4

Functions of Nephron Structures Distal Convoluted Tubule (DCT) –receives dilute fluid from the ascending limb of the Loop of Henle – Variably active portion of the nephron –When aldosterone hormone is present, sodium is reabsorbed and potassium is secreted. Water and chloride follow the sodium. Unit 1 - Objective 4

Functions of Nephron Structures Collecting Duct –receives fluid from the DCT – variably active portion of the Nephron –when antidiuretic hormone ( ADH ) is present, this duct will become porous to water. Water from the collecting duct fluid then moves by osmosis into the “salty” (hyperosmotic) interstitium of the medulla. –The last segment to save water for the body Unit 1 - Objective 4

Functions of Nephron Structures Peritubular Capillaries –transport reabsorbed materials from the PCT and DCT into kidney veins and eventually back into the general circulation –help complete the conservation process (reabsorption) that takes place in the kidney Unit 1 - Objective 4

Objective 5 Describe the formation of urine and its composition.

 Urine formation is simple:  glomerular filtration - urine formation begins, plasma is filtered  tubular reabsorption - returns most of the fluid to the body - PROXIMAL TUBULE  tubular secretion - removes what is not needed; produces urine - DISTAL TUBULE Urine Composition 95 % Water Contains urea and uric acid (characteristic smell) Can contain trace amino acids Urine may also contain other chemicals that can be detected. Hormones present in a pregnant woman are detectable in urine

Table 18.2

Table 18.3

Objective 10 Give the cause and describe the disease process for the following: renal calculi (kidney stones); cystitis; gout; Glomerulonephritis (Bright’s Disease); incontinence. Unit 1 - Objective 10

Disorders of the Urinary System Renal Calculi (kidney stones) –caused by the crystallization of calcium, magnesium or uric acid salts that precipitate in the renal pelvis. –If the calculi become large and travel down the ureter, they can cause excruciating pain which radiate from the flank to the anterior abdominal wall on the same side. Unit 1 - Objective 10

Disorders of the Urinary System Cystitis –typically caused by bacteria from the anal region, but, can also be caused by sexually transmitted diseases and various chemical agents –can lead to inflammation, fever, increased urgency and frequency of urination and pain Unit 1 - Objective 10

Disorders of the Urinary System Glomerulonephritis ( Bright’s Disease) –caused by inflammation of the glomeruli due to an abnormal immune response (autoimmune, streptococcal antibody complexes). –Inflammation of the glomeruli leads to faulty filtration (passage of blood cells and proteins) and possible kidney failure. Unit 1 - Objective 10

Disorders of the Urinary System Incontinence –caused by loss of the ability to control voluntary micturition (releasing urine from the bladder) due to age, emotional disorders pregnancy, damage to the nervous system, stress, excessive laughing and coughing –leads to wetting of clothing, discomfort and embarassment Unit 1 - Objective 10

Objective 11 Describe the process involved in dialysis therapy. Unit 1 - Objective 11

Dialysis Therapy Dialysis is a process that artificially removes metabolic wastes from the blood in order to compensate for kidney (renal) failure. Kidney failure results in the rapid accumulation of nitrogen waste (urea, etc.) which leads to azotemia. Uremia and ion disturbances can also occur. This condition can cause acidosis, labored breathing, convulsions, coma and death. Unit 1 - Objective 11

Dialysis Therapy The most common form of dialysis is hemodialysis which uses a machine to transfer patient’s blood through a semipermeable tube that is permeable only to selected substances. The dialysis machine contains an appropriate dialysis fluid that produces a diffusion gradient. This gradient allows abnormal substances to diffuse from the patient’s blood and produce a “cleaning” effect. Unit 1 - Objective 11

Dialysis Therapy Some key aspects of hemodialysis are: - blood is typically transferred from an arm artery - after dialysis, blood is typically returned to an arm vein - to prevent clotting, blood is typically heparinized - dialysis sessions occur about three times a week - each dialysis session can last four to eight hours! - long term dialysis can lead to thrombosis (fixed blood clots), infection and death of tissue around a shunt (the blood access site in the arm) Unit 1 - Objective 11