Principles of Human Anatomy and Physiology, 11e1 Chapter 26 The Urinary System Lecture Outline

Principles of Human Anatomy and Physiology, 11e2 INTRODUCTION Study of the structure, function, and diseases of the kidneys is nephrology. The branch of surgery related to the urinary system is called urology. The urinary system helps maintain homeostasis by: –Altering blood composition, pH, volume, and pressure –Maintaining blood osmolarity –Excreting wastes –Producing hormones –Regulates ions in our blood, like Na+, K+, Ca2+, and Cl-

Components The urinary system consists of 2 kidneys, 2 ureters, 1 bladder, and 1 urethra. The main function of the kidneys is to filter the blood and produce urine. Urine is made up of water and solutes removed from our blood. Principles of Human Anatomy and Physiology, 11e3

4 External Anatomy of Kidney Paired kidney-bean-shaped organ 4-5 in long, 2-3 in wide, 1 in thick Found just above the waist between the peritoneum & posterior wall of abdomen

Internal Anatomy of the Kidney The outside of a kidney is called the renal cortex and is reddish brown in color. The inside of a kidney is called the renal medulla. Principles of Human Anatomy and Physiology, 11e5

Nephrons The functional unit of a kidney is a nephron There are millions of nephrons found in each of your kidneys. Principles of Human Anatomy and Physiology, 11e6

Nephron Anatomy Blood enters the kidney through the glomerulus which is a ball of capillaries. It is surrounded by a protective capsule called the Bowman’s capsule. Blood is filtered here and then moves on to the rest of the nephron. Principles of Human Anatomy and Physiology, 11e7

Nephron Anatomy Blood then goes through the proximal tubule, down the descending Loop of Henle, up the ascending Loop of Henle, and through the distal tubule. At each step, the nephron is removing useful things from blood, like water, nutrients, minerals, and salts that were absorbed by the digestive system. Principles of Human Anatomy and Physiology, 11e8

Nephron Anatomy After going through the nephron, all that’s left is waste. The waste is collected in the collecting duct and sent to the ureter to travel to the bladder for storage. Principles of Human Anatomy and Physiology, 11e9

Urine You produce 1 to 2 liters of urine every 24 hours. Urine should be clear to pale yellow in color. Urine should be transparent (clear) It is mildly aromatic and smells like ammonia when left standing pH of urine ranges from 4.6 to 8.0, with an average of % of urine is water, the remaining 5% is electrolytes, salts, and drugs. There should never be protein in your urine Principles of Human Anatomy and Physiology, 11e10

The Bladder The bladder is a hollow, stretchable muscular organ located in the pelvic cavity. Urinary bladder capacity ranges from mL, slightly less in females because of the uterus Principles of Human Anatomy and Physiology, 11e11

Urethra The urethra is a small tube leading from the bladder to the exterior of the body. In men, it also carries sperm. Principles of Human Anatomy and Physiology, 11e12

Development of the Urinary system By week 3 of pregnancy, kidneys begin to form Fetuses go through 3 pairs of kidneys before birth, only the last one remains at the time of birth By month 3, fetuses begin producing urine, which remains in the amniotic fluid Principles of Human Anatomy and Physiology, 11e13

Principles of Human Anatomy and Physiology, 11e14 Aging and the Urinary System After age 40, the effectiveness of kidney function begins to decrease. Kidneys shrink Filters less effectively, you are more thirsty Diseases and infections are more common Cancer of prostate is common in elderly men

Diseases and Disorders Nephroptosis or floating kidney, is an inferior displacement or dropping of the kidney. Common in thin people who don’t have enough fat to hold the kidney in place. It’s dangerous because it may block urine flow. Principles of Human Anatomy and Physiology, 11e15

Diseases and Disorders Glucosuria is when you have too much glucose in your blood for the kidney to filter (common in diabetics) Some glucose then remains in the urine causing increased urinary output, decreased blood volume, and dehydration. Principles of Human Anatomy and Physiology, 11e16

Diseases and Disorders Diuretics are substances that slow renal reabsorption of water and cause elevated urine flow. These include coffee, tea, soda, and alcohol. These all inhibit the secretion of ADH and cause you to pee more. Principles of Human Anatomy and Physiology, 11e17

Diseases and Disorders During cytoscopy a small camera is inserted through the urethra into the bladder and/or prostate. The bladder can be visually inspected and tissue samples can be collected Principles of Human Anatomy and Physiology, 11e18

Diseases and Disorders In urinary incontinence you no longer have control over your bladder muscles and pee leaks out. This is common in small children and older adults. It can also be caused by physical stress on the bladder (lifting heavy things, sneezing, laughing, being pregnant) Principles of Human Anatomy and Physiology, 11e19

Diseases and Disorders Kidney stones are insoluble salt crystals that lodge in the ureter. Causes include poor diet, not enough water, or too much calcium They can be dissolved through sending high energy shock waves through the body Principles of Human Anatomy and Physiology, 11e20

Diseases and Disorders A UTI is a urinary tract infection. They are caused by bacteria getting into the urethra and are more common in females because they have shorter urethras. Symptoms include painful or burning urination and low back pain Cured by antibiotics Principles of Human Anatomy and Physiology, 11e21

Diseases and Disorders Renal failure is when the nephrons in your kidneys either decrease in function or stop working. Can be caused by illness or injury, drugs, or low blood pressure. Dialysis and kidney transplant are possible treatments. Principles of Human Anatomy and Physiology, 11e22

Draw a Kidney Use page 996 as a reference Include a picture and labels of important structures. Must be colored Due at the end of the period Principles of Human Anatomy and Physiology, 11e23