It is the urinary system that is primarily concerned with
the removal of nitrogenous wastes from the body
kidneys maintain the balance of
electrolytes
acid-base ratio
fluids
the major homeostatic organ
kidney
the kidney excretes
toxins, metabolic wastes, & excess ions in the urine
the kidney retains needed substances by
returning them to the blood
the kidney regulates
blood volume, pH, & chemical composition
Urinary System Organs
Kidneys, Urinary bladder, Ureters, Urethra
Blood flows into the kidney through
renal arteries
renal arteries
break up into the segmental arteries which enter the hilum
segmental arteries
interlobar arteries (arcuate arteries)-- cortical radiate arteries, afferent arteries
cortical radiate veins
arcuate veins -interlobar veins - renal vein- into the pelvis region
nephrons form
urine
two distinct capillary beds (two main parts of nephrons)
glomerulus
renal tubule
glomerulus (capillary knot)
a tuft of capillaries
renal tubule
begins as cup-shaped glomerular (Bowman's) capsule surrounding glomerulus
the inner visceral wall creates a porous epithelial which is an important part of the
filtration membrane
From the capsule the portions of the tubule are
-proximal convoluted tubule
-Loop of Henle
-Distal convoluted tubule
Proximal Convoluted tubule
receives filtrate from the glomerular capsule and is the site of tubular reabsorption
distal convoluted duct leads into a
collecting duct (receives urine from many nephrons)
__________ _____ give medullary pyramids their striped appearance
collecting ducts
As collecting ducts approach the renal pelvis, they fuse together and empty the urine into the
minor calyces via the papillae of the pyramids
the two capillary beds:
glomerulus
peritubular capillary bed
Urine formation is the result of three processes:
filtration, reabsorption, and secretion
filtration occurs in the
glomerulus
reabsorption and secretion begin in the
proximal convoluted tubule
Secretion involves materials either moving from the blood of the ___________ ___________ or from the tubular cells into the ________
peritubular capillaries; filtrate
chemical composition of urine
95% water and 5% solutes
Blood composition depends on 3 major factors:
diet, cellular metabolism, and urinary output
pH characteristics of urine
ranges from 4.5 to 8.0 with the average at 6.0
-diet can alter pH of urine
-bacterial infection can alter pH
specific gravity of urine is
slightly more than water, since it contains solutes
1.001 dilute urine results when
one drinks lots of water, uses diuretics, suffers from diabetes insipid us, or chronic renal failure
1.030 on the high end (concentrated) can result from
limited fluid intake, fever, kidney inflammation (pyelonephritis) or diabetes mellitus
abnormal urinary constituents
glucose
albumin
(Abnormal Urinary Constituents)
glucose due to
high carb intake or diabetes mellitus, diabetes insipidus
(Abnormal Urinary Constituents)
albumin indicative of
& due to:
abnormal permeability of the glomerular membrane
-excessive excretion, pregnancy, glomerulonephritis
(Abnormal Urinary Constituents)
-Keytone bodies
occur during starvation, or diets low in carbs
(Abnormal Urinary Constituents)
red blood cells
cystitis, irritation of the urinary tract organs
infection, inflammation
(Abnormal Urinary Constituents)
white blood cells
pus- inflammation of the urinary tract, cystitis, or pyelonephritis
(Abnormal Urinary Constituents)
casts due to
glomerulonephritis, pyelonephritis
kidney acts as a blood ______ then as a blood _________
filter; processor
ureters
drain urine from the kidneys and conduct it by peristalsis to the bladder for temporary storage
urinary bladder
receives urine from ureters and discharges it via the urethra, stores it temporarily
urethra
drains the bladder
-the superficial kidney region, lighter in color
-rich vascular supply
kidney cortex
-deep to the cortex, darker reddish-brown color
-segregated into triangular regions that have a striped appearance
medullary region
-base of each faces toward the cortex
-pointed papilla (apex) points to the innermost kidney
medullary (renal) pyramids
-areas of tissue that are more like the cortex in appearance
-segregate and dip inward between pyramids
renal columns
-extends inward from hilum
-relatively flat, basin like cavity that is continuous with the ureter (exits from hilum region)
renal pelvis
(Abnormal Urinary Constituents)
high specific gravity
diabetes mellitus, pyelonephritis
4 characteristics of urine
color variations
odor
pH
specific gravity