THE URINARY SYSTEM
Function:
1. Filters ___________________ from the blood
2. Maintains the body's ___________________ balance
___________________ - toxic levels of cellular waste
Urine contains many substances including:
Water, ___________________, Creatinine, ___________________, Hippuric Acid, Ketone bodies, NaCl, K, SO4, PO4, NH4, Mg, Ca
May also contain: Albumin, ___________________, Erythrocytes, ___________________, Bilirubin,
Renal Calculi (kidney stones), Microbes
Analysis of abnormal urine may indicate:
___________________, liver disease, kidney or bladder infections, anorexia or starvation
Normal values:
Volume - 1-2 liters
Color - Yellow or amber but varies with ___________________
pH - 4.6 - 8; average 6.0; varies
specific gravity - 1.001-1.035
ANATOMY:
___________________ - 2; located just above the waistline under the muscles of the back and
behind the abdominal cavity. Usually held in place by a cushion of fat.
Renal ___________________ = "kidney drop" caused by a lack of the fat layer in extremely thin persons.
Internal structure -
___________________ - outer part
___________________ - inner part
___________________ - the triangular divisions of the medulla
___________________ - the narrow ends of the pyramids
___________________ - the widened upper end of the ureter
___________________ - a division of the pelvis that drains urine from the papilla to the ureter
Microscopic Structure:
___________________ - the functional unit of the kidney; over a million in each kidney;
Composed of two parts =
1. Renal ___________________
a. Glomerulus - a network of blood capillaries containing blood at high
pressure (the vessel bringing blood into the glomerulus is the afferent
arteriole and the vessel carrying blood out of the glomerulus is the
efferent arteriole).
b. ___________________ capsule - the sack-like capsule that surrounds the glomerulus
2. Renal Tubule
a. ___________________ Convoluted Tubule - the first segment; nearest the capsule
b. Loop of ___________________ - a narrow tube that consists of a descending portion, a
loop, and an ascending portion
c. ___________________ convoluted tubule - the part distal to the Loop of Henle
d. ___________________ tubule - a straight tubule that is formed from the joining of several distal
tubules.
How Kidneys Form Urine:
3 Processes in urine formation -
___________________, ___________________, ___________________
1. Filtration -
The ___________________ arteriole is smaller in diameter than the ___________________
arteriole. This creates pressure in the ___________________ that forces the plasma portion of the
blood into the Bowman's capsule. Filtration occurs at a rate of 125 ml/min. or 180 liters/day.
2. Resorption - the movement of substances from the tubules into the capillaries. ___________________, ___________________, other nutrients, sodium, and other ions are resorbed in the tubules, (approx. ___________________% of the filtrate is resorbed in the proximal tubule).
Resorption of nutrients like glucose takes place by ___________________ transport so that no
glucose is lost in the urine (except in ___________________). Minerals, such as sodium, are only
partially resorbed. The amount depends on intake. This is how sodium balance is maintained.
3. Secretion - the process by which substances move from the capillaries into the distal and
collecting tubules. Hydrogen ions, potassium, & other chemicals and drugs are actively transported
out of blood into urine.
CONTROL OF URINE VOLUME:
ADH (___________________ Hormone) decreases the amount of urine produced by making the
collecting tubules more permeable to ___________________. When no ADH is present the distal
and collecting tubules are almost impermeable to water.
___________________ (from the adrenal cortex) stimulates the tubules to resorb sodium and water.
___________________ - 1/4 inch diameter; 10-12 inches long; lined with mucous membrane;
muscular contractions similar to peristalsis aid in moving urine down to the bladder.
___________________ - the inner surface is wrinkled in folds called ___________________, except
for a smooth triangular area called the ___________________, located between the openings of the
two ureters above and the urethra below.
___________________ - urinary tube carries urine to the external opening, the urinary meatus.
Females - 1.5 inches (carries only urine)
Males - 8 inches (carries urine and ___________________)
MICTURITION = URINATION = VOIDING
Internal urethral sphincter - ___________________
External urethral sphincter - ___________________
Voiding pressure begins at approx 150 ml but voiding usually does not occur until a volume of ___________________ ml occurs.
Pressure stimulates a nerve which causes contraction of the smooth muscles of the bladder and relaxation of the smooth muscle of the internal sphincter.
If the striated muscle of the external sphincter is relaxed voiding will occur.
___________________ - absence of urine
___________________ - scanty urine
___________________ - much urine
Urinary ___________________ - bladder does not empty
Urinary ___________________ - no urine is produced
___________________ - patient voids involuntarily
___________________ - bladder infection