Chapter 9: Urinary System

Dietetics

The science of how food and nutrition affect our health

Dieticians

Providers that specialize in food and nutrition. Their goal is to prevent and improve health through nutrition and patient education

Registered Dietician (RD)

Asses nutritional needs, diet restrictions and current health, develops and implements dietary care plans, and educates patients

Dietetic Technician, Registered (DRT)

Conducts screens, gathers data, and preforms tasks to assist the Registers Dietician to provide medical nutrition therapy

Urinary System

Responsible for maintaining a stable internal environment for the body. Removes waste products, adjusts water and electrolyte levels, and maintains the correct pH; These waste materials result in the production and excretion of urine from the body

• kidneys

• urethra

• ureters

• urinary bladder

The primary structures / organs that compromise the urinary system:

Genitourinary System (GU)

Main function is to filter and remove waste products from the blood; Organs of the urinary system and female or male sexual organs; Another name for the urinary system

Filtration

The genitourinary system (GU) is similar to a ____ plant.

Metabolic

All the body’s ______ processes result in the production of waste products.

Toxic

Waste products are a natural part of life but quickly become _____ if they are allowed to build up in the blood.

Uremia

Excess of urea and other nitrogenous waste in blood

Tubules

Waste products in the body are removed through a very complicated system of blood vessels and kidney ________.

Nephrons

Functional or working unit that kidney that filters blood and produces urine; More than 1 million in adult kidney; Each consists of renal corpuscle and renal tubules; Makes up each kidney

Ureters

Organs (2) in urinary system that transport urine drained from the kidney to the urinary bladder; Narrow tubes (measuring less than ¼-inch wide and 10–12 inches long that extend from the renal pelvis to the urinary bladder) that leave the kidneys at the hilum and lead to the bladder; narrow tubes; Mucous membrane lined

Urinary Bladder

Organ in urinary system that stores urine; An elastic muscular sac that lies in the base of the pelvis just behind the pubic symphysis; Receives urine directly from ureters, stores it, and excretes it by urination through the urethra

Quart

The body is constantly producing urine, and the bladder can collect up to one ______ of this liquid during the night. Generally, an adult bladder signals the urge to void when it contains 300–400 mL of urine.

Urethra

Tubular canal that carries the flow of urine from urinary bladder to outside of body; Mucous membrane lined (One of the reasons that bladder infections may spread up the urinary tract); In male it is also used by reproductive system to release semen

Two (2)

The body has _____ kidneys located in the lumbar region of the back above the waist, with one on either side of the vertebral column. They are not inside the peritoneal sac, a location referred to as retroperitoneal.

Retroperitoneal

Pertaining to behind peritoneum; Describes position of kidneys, which is outside of peritoneal sac alongside spine

Concave

Each kidney has a _____ or indented area on the edge toward the center that gives the kidney its bean shape. The center of this concave area is called the hilum.

Hilum

Controlled entry/exit point of an organ such as kidney or lung; Where the renal artery enters the renal vein leaves the kidney

Renal Artery

Artery that originates from abdominal aorta and carries blood to nephrons of kidney; Delivers blood that is full of waste to the kidney

Renal Vein

Carries cleansed blood away from kidneys for general circulation

Cortex

Outer layer of organ; Within endocrine system, refers to outer layer of adrenal glands; Within urinary system, refers to outer layer of kidney

Medulla

Middle area of an organ; In endocrine system refers to adrenal medulla; In urinary system, refers to inner portion of kidney; Contains a dozen or so triangular-shaped areas called the renal pyramids

Renal Pyramids

Triangular-shaped region of renal medulla. The tip of each _____ points inward toward the hilum

Calyx (plural is Calyces)

Duct that connects renal papilla to renal pelvis; Urine flows from collecting tubule through calyx and into renal pelvis

Renal Papilla

Tip of renal pyramid; Each pyramid opens into a calyx

Renal Pelvis

Large collecting site for urine within kidney; Collects urine from each calyx; Urine leaves renal pelvis via ureter

Formed

The calyces and ultimately the renal pelvis collect urine as it is ______.

Arises

The ureter for each kidney _____ from the renal pelvis.

Fist

Each kidney weighs four to six ounces, is two to three inches wide and approximately one inch thick, and is about the size of your ______.

Working

In most people, the left kidney is slightly higher and larger than the right kidney. Functioning kidneys are necessary for life, but it is possible to live with only one ______ kidney.

Renal Corpuscle

Part of a nephron; Bowman capsule and contains the glomerulus; Afferent arteriole carries blood to glomerulus and efferent arteriole carries blood away from glomerulus; Filtration stage of urine production occurs in _______ as wastes are filtered from blood in glomerulus and enter Bowman capsule

Renal Tubule

Network of tubes found in a nephron; Where reabsorption and secretion stages of urine production occur; As glomerular filtrate passes through, most of water and some of dissolved substances, such as amino acids and electrolytes, are reabsorbed; At same time, substances that are too large to filter into Bowman capsule, such as urea, are secreted directly from bloodstream into _______; Filtrate that reaches collecting tubule becomes urine

Glomerular Capsule

Part of renal corpuscle; Double-walled cuplike structure that encircles glomerulus; Within filtration stage of urine production, waste products filtered from blood enter _______ as glomerular filtrate; Also called Bowman capsule

Glomerulus

Ball of capillaries encased by glomerular capsule; Within filtration stage of urine production, wastes filtered from blood leave glomerulus capillaries and enter Bowman capsule

Afferent Arteriole

Arteriole that carries blood into glomerulus

Efferent Arteriole

Arteriole that carries blood away from glomerulus

Afferent

Term: Moving Toward

Efferent

Term: Moving Away From

• Proximal Convoluted Tubule

• Nephron Loop (Loop of Henle)

• Distal Convoluted Tubule

• Collecting Tubule

The four (4) divided sections of the renal tubule:

Smooth

The urinary bladder is composed of three layers of ______ muscle tissue lined with mucous membrane containing rugae that allow it to stretch.

Rugae

Prominent folds in mucosa of stomach; Smooth out and almost disappear allowing stomach to expand when full of food; Also found in urinary bladder

Urination

Release of urine from urinary bladder; Also called micturition or voiding

Internal Sphincter

Ring of involuntary muscle that keeps urine within bladder; Prevents the bladder from emptying at the wrong time

Involuntary

______ muscle action causes the bladder to contract and the internal sphincter to relax.

Voluntary

______ muscle action controls the external sphincter, which opens on demand to allow the intentional emptying of the bladder.

External Sphincter

Ring of voluntary muscle that controls emptying of urine from bladder; The act of controlling the emptying of urine is developed sometime after a child is two years of age

Urinary Meatus

External opening of urethra through which urine passes out of the body

• 1-2 inches long

• Functions only as an outlet for urine

• Located in the front of the vagina

Urethra in Women:

• 8 inches long

• An outlet for urine

• Passageway for semen to leave the body

Urethra in Men:

Homeostasis

Steady state or state of balance within body; Kidneys responsible for maintaining; Continually adjust the chemical conditions in the body, allowing humans to survive

Balance

Because of its interaction with the bloodstream and its ability to excrete substances from the body, the urinary system maintains the body’s proper _____ of water (H₂O) and chemicals.

Excrete

If the body is low on water, the kidneys conserve it or, in the opposite case, if there is excess water in the body, the kidneys _____ the excess.

Regulate

In addition to water, the kidneys _____ the level of electrolytes—small biologically important molecules such as sodium (Na+), potassium (K+), chloride (cl−), and bicarbonate (HCO3−).

pH

Kidneys play an important role in maintaining the correct _____ range within the body, making sure it does not become too acidic or too alkaline. The kidneys accomplish these important tasks through the production of urine.

Desirable

As wastes and unnecessary substances are removed from the bloodstream by the nephrons, many _____ molecules are also removed initially.

Waste products are eliminated from the body, but other substances such as water, electrolytes, and nutrients must be _____ to the bloodstream.

Returned

Urine, in its final form ready for ______ from the body, is the ultimate product of the urine production process.

Elimination

• Filtration

• Reabsorption

• Secretion

Three (3) stages of urine production:

Filtration

First stage of urine production during which waste particles (occurs in the renal corpuscle) are filtered from blood; Pressure of blood flowing through the glomerulus forces material out of the bloodstream, through the wall of the glomerular capsule, and into the renal tubules. This fluid in the tubules is called the glomerular filtrate

Glomerular Filtrate

Product of filtration stage of urine production; water, electrolytes, nutrients, wastes, and toxins that are filtered from blood passing through Glomerulus; Filtrate enters Bowman capsule

Reabsorption

Second phase of urine production; Substances needed by body are reabsorbed as filtrate passes through kidney tubules; Passes through the four sections of the tubule; Most of the water and much of the electrolytes and nutrients are reabsorbed into the peritubular capillaries; They can then reenter the circulating blood

Peritubular Capillaries

Capillary bed surrounding renal tubules

Secretion

Third phase of urine production; Additional waste products are added to filtrate as it passes through kidney tubules; Occurs when the special cells of the renal tubules secrete ammonia, uric acid, and other waste substances directly into the renal tubule; Urine formation is now finished; It passes into the collecting tubules, renal papilla, calyx, renal pelvis, and ultimately into the ureter

Dilute

Normal urine color may vary from almost clear, pale yellow, to deep gold, depending on how _____ it is.

As urine is being produced and collecting in the bladder, it is ______. However, as it passes through the urethra to the outside, it may become contaminated by bacteria.

Sterile

Although urine is ____ water, it also contains many dissolved substances, such as electrolytes, toxins, and nitrogenous wastes, the by-products of protein metabolism.

95%

Nitrogenous Wastes

Waste products that contain nitrogen; Products, such as ammonia and urea, are produced during protein metabolism

Urea

Waste product of protein metabolism; Diffuses through tissues in lymph and is returned to circulatory system for transport to kidneys

Approximately 95% of the nitrogenous waste is in the ____ of urea.

Form

By producing urea, the body prevents the waste nitrogen from becoming _____, which is highly toxic to cells. At times the urine also contains substances that should not be there, such as glucose, blood, or albumin, a protein that should remain in the blood.

Ammonia

Albumin

Protein normally found circulating in bloodstream; It is abnormal for albumin to be in urine

Urinalysis (U/A, UA)

Laboratory test consisting of physical, chemical, and microscopic examination of urine; Gives medical personnel important information regarding disease processes occurring in a patient.

Normally, during a 24-hour period the output of urine will be 1,000–2,000 mL, depending on the amount of fluid consumed and the general ____ of the person

Health

Normal urine is ____ because this is one way the body disposes of excess acids.

Acidic

Specific Gravity (SG, sg. gr.)

Characteristic of urine that indicates amount of dissolved substances in urine; Urine varies from 1.001 to 1.030; Highly concentrated urine has a higher _____, while the ____ of very dilute urine is close to that of water