The Urinary System PDF

The Urinary System Learning Outcomes: 1. Summarize the functions of the urinary system 2. Identify the organs of the urinary system and state their function Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of...

The Urinary System Learning Outcomes: 1. Summarize the functions of the urinary system 2. Identify the organs of the urinary system and state their function Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 1  Functions of the Urinary System Functions of the urinary system – Excretes metabolic wastes from the body Most are nitrogenous, such as urea and uric acid Urea – a waste product of breaking down amino acids Uric acid – from breaking down nucleotides Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 2 3  Functions of the Urinary System, continued Functions of the urinary system, cont. – Maintenance of water-salt balance of the blood – Maintenance of acid-base balance of the blood – Secretion of hormones Erythropoietin (EPO) – stimulates the production of red blood cells Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 4  Organs of the Urinary System The urinary system consists of the kidneys, ureters, urinary bladder, and urethra Kidneys – A renal artery enters and a renal vein and ureter exit The renal artery transports blood to the kidneys; the renal vein carries filtered (cleansed) blood away from the kidneys Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 5 6  Organs of the Urinary System Ureters – Conduct urine from the kidneys to the bladder Urinary bladder – Stores urine – Has three openings: two for the ureters, and one for the urethra, which drains the bladder Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 7  Organs of the Urinary System There are two sphincters where the urethra exits the bladder – The internal sphincter is composed of smooth muscle and is involuntarily controlled – The external sphincter is composed of skeletal muscle that can be voluntarily controlled Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 8  Urination Urination – When the urinary bladder fills with urine, stretch receptors are activated – These receptors send nerve signals to the spinal cord Subsequently, nerve impulses cause the urinary bladder to contract and the sphincters to relax, so that urination is possible The brain has control over urination, too, by controlling the external urethral sphincter Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 9 10  Urethra Urethra – Extends from the urinary bladder to an external opening Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 11  Check Your Progress 1. List and briefly describe the functions of the organs of the urinary system 2. Summarize the processes the kidneys perform to maintain homeostasis 3. Predict what could occur to overall homeostasis if the kidneys could not excrete metabolic waste products from the body Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 12  Kidney Structure Learning Outcomes: 1.Identify the structures of a human kidney 2.Identify the structures of a nephron and state the function of each Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 13  Kidney Structure, continued The three regions of a kidney: 1. Renal cortex – outer layer 2. Renal medulla – consists of cone- shaped renal pyramids 3. Renal pelvis – a central space that is continuous with the ureter Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 14 15  Kidney Structure, cont. Kidneys are composed of over 1 million nephrons – The nephrons filter the blood and produce urine – Several nephrons empty urine into one collecting duct – The collecting ducts empty into the renal pelvis Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 16  The Nephron Blood supply of the nephron – From the renal artery, an afferent arteriole transports blood to the glomerulus, a knot of capillaries inside the glomerular capsule – The efferent arteriole carries blood away from the glomerulus Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 17 18  The Nephron, continued Blood supply of the nephron, cont. – The efferent arteriole empties into the peritubular capillary network, which surrounds the rest of the nephron – Then the blood goes into a venule that carries blood into the renal vein Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 19  Anatomy of a Nephron Parts of a nephron – Glomerular capsule Podocytes cover the glomerulus, leaving pores that allow molecules from the blood inside the glomerulus out into the glomerular capsule – Proximal convoluted tubule Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 20  Anatomy of a Nephron, continued Parts of a nephron, cont. – Loop of the nephron – Distal convoluted tubule – Collecting duct carries urine to the renal pelvis Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 21  Check Your Progress 1. Name the three major areas of a kidney 2. Describe the paths of blood and fluids in the nephron Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 22  Urine Formation Learning Outcomes: 1. Summarize the three processes involved in the formation of urine 2. List the components of the glomerular filtrate 3. Describe how tubular reabsorption processes nutrient and salt molecules 4. Explain the substances that are removed from the blood by tubular secretion Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 23  Urine Formation, continued The formation of urine involves three stages: 1. Glomerular filtration 2. Tubular reabsorption 3. Tubular secretion Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 24  Glomerular Filtration Glomerular filtration – Occurs when blood enters the glomerulus via the afferent arteriole – Increased blood pressure forces more fluid and molecules to leave the glomerulus than in typical capillaries Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 25  Glomerular Filtration, continued Glomerular filtration, cont. – This fluid, called glomerular filtrate, enters the glomerular capsule – This process is called filtration because large molecules and formed elements are unable to pass through the capillary wall, but small ones easily fit Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 26 27  Glomerular Filtration, cont. Components of filtrate: – Water, nitrogenous wastes, nutrients, salts (ions) What is held back (stays in the blood): – Formed elements (blood cells and platelets), plasma proteins Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 28  Tubular Reabsorption Tubular reabsorption – Molecules are reabsorbed from the nephron into the blood of the peritubular capillaries – Nutrients such as glucose and amino acids are reabsorbed Glucose is normally reabsorbed completely Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 29  Diabetes Mellitus Diabetes mellitus – Blood glucose is above normal and glucose appears in the urine The glucose transporters are overwhelmed; they can’t reabsorb all of the glucose in the filtrate Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 30  Tubular Secretion Tubular secretion – The second way by which substances move from blood to the filtrate (the first is filtration) – Drugs such as penicillin are secreted – In the end, urine contains: *** Substances that have been filtered, but not reabsorbed plus what has been secreted *** Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 31  Biology Today: Health Urinalysis – Characteristics of normal urine: color is usually pale yellow However, may vary from colorless (dilute) to dark yellow (concentrated) – Abnormal findings in urine: glucose, blood, white blood cells Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 32  Check Your Progress 11.3 1. List the three major processes in urine formation, and state the location in the nephron where each occurs 2. Summarize the functions of glomerular filtration, tubular reabsorption, and tubular secretion 3. List the components of the blood that are reabsorbed, and those that are excreted during urine formation Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 33  Kidneys and Homeostasis Learning Outcomes: 1. Summarize how the kidney maintains the water-salt balance of the body 2. State the purpose of ADH and aldosterone in homeostasis Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 34  Reabsorption of Salt and Water from Cortical Portions of the Nephron Hormones regulate the reabsorption of sodium and water – Aldosterone is a hormone secreted by the adrenal glands that increases the reabsorption of sodium Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 35  Antidiuretic Hormone Antidiuretic hormone (ADH) is produced by the hypothalamus and secreted by the posterior pituitary in response to an increase in blood concentration (dehydration) – Water is then reabsorbed, decreasing urine volume Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 36  Diuretics Diuretics – increase the production of urine – E.g., alcohol increases urine production by inhibiting secretion of ADH – E.g., caffeine increases the rate of glomerular filtration – E.g., diuretic drugs for high blood pressure Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 37  Check Your Progress 1. Detail the differences between dilute and concentrated urine 2. Describe the action of the hormones used to influence urine production Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 38  Urinary System Disorders Learning Outcomes: 1. List the major diseases of the urinary system and summarize their causes 2. Describe how hemodialysis can help restore homeostasis of the blood in the event of kidney failure Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 39  Urinary System Disorders, cont. Urinary tract infections or an intake of too much calcium can lead to kidney stones – Form in the renal pelvis and usually pass unnoticed in the urine flow – If large, can block the renal pelvis or ureter Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 40  Hemodialysis Hemodialysis – An artificial kidney machine – The diffusion of dissolved molecules through a membrane that allows only small molecules to pass through – The patient’s blood is passed through a membranous tube that is in contact with a dialysis solution Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 41  Hemodialysis, continued Hemodialysis, cont. – Substances more concentrated in the blood diffuse into the dialysis fluid, and substances more concentrated in the dialysis fluid diffuse into the blood Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 42  Replacing a Kidney Patients with renal failure sometimes undergo a kidney transplant operation As with all organ transplants, there is the possibility of organ rejection Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 43  Check Your Progress 1. Provide examples of diseases associated with the urinary tract and kidneys 2. Explain why hemodialysis would need to be done frequently in a patient with renal failure Copyright © 2018 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of 44