Urinary system ppt – anatomy power point
In females, the urinary bladder is in contact with the uterus posterosuperiorly and with the vagina posteroinferiorly.
In males, it is in contact with the rectum posterosuperiorly and is immediately superior to the prostate gland.
The urinary bladder is a retroperitoneal organ.
When empty, the urinary bladder exhibits an upside-down pyramidal shape.
Filling with urine distends it superiorly until it assumes an oval shapeUrinary Tract – Urinary Bladder
A posteroinferior triangular area of the urinary bladder wall, called the trigone is formed by imaginary lines connecting the two posterior ureteral openings and the anterior urethral opening.
The trigone remains immovable as the urinary bladder fills and evacuates.
It functions as a funnel to direct urine into the urethra as the bladder wall contracts to evacuate the stored urine.
The four tunics that form the wall of the bladder are the mucosa, submucosa, muscularis, and adventitia.
The expulsion of urine from the bladder.
Initiated by a complex sequence of events called the micturition reflex.
The bladder is supplied by both parasympathetic and sympathetic nerve fibers of the autonomic nervous system.
Fibromuscular tube that exits the urinary bladder through the
urethral opening from its anteroinferior surface and conducts urine to the exterior of the body.
The luminal lining of the urethra is a protective mucous membrane that houses clusters of mucin-producing cells called urethral glands.
Bundles of primarily smooth muscle fibers surround the mucosa and help propel urine to the outside of the body.
Two urethral sphincters restrict the release of urine until thepressure within the urinary bladder is high enough and voluntary activities needed to release the urine are activated.
The internal urethral sphincter is the involuntary, superior sphincter surrounding the neck of the bladder, where the urethra originates.
a circular thickening of the detrusor muscle and is controlled by the autonomic nervous system
The external urethral sphincter is inferior to the internal urethral sphincter and is formed by skeletal muscle fibers of the urogenital diaphragm.
a voluntary sphincter controlled by the somatic nervous system
this is the muscle children learn to control when they become “toilet-trained”
Has a single function:
to transport urine from the urinary bladder to the vestibule, an external space immediately internal to the labia minora
3 to 5 centimeters long, and opens to the outside of the body at the external urethral orifice located in the female perineum.
Urinary and reproductive functions:
passageway for both urine and semen
Approximately 18 to 20 centimeters long.
Partitioned into three segments:
prostatic urethra is approximately 3 to 4 centimeters long and is the most dilatable portion of the urethra extends through the prostate gland, immediately inferior to the male bladder, where multiple small prostatic ducts enter it
membranous urethra is the shortest and least dilatable portion extends from the inferior surface of the prostate gland through the urogenital diaphragm
spongy urethra is the longest part (15 centimeters) encased within a cylinder of erectile tissue in the penis called the corpus spongiosum extends to the external urethral orifice
Aging and the Urinary System
Changes in the size and functioning of the kidneys begin at 30.
Gradual reduction in kidney size.
Reduced blood flow to the kidneys.
Decrease in the number of functional nephrons.
Reabsorption and secretion are reduced.
Diminished ability to filter and cleanse the blood.
Less aldosterone or antidiuretic hormone.
Ability to control blood volume and blood pressure is reduced.
Bladder decreases in size.
More frequent urination.
Control of the urethral sphincters—and micturation may be lost