SOLUTIONS TO EXERCISES, LESSON 8
The human urogenital systems are made up of the urinary organs, which produce
the fluid called urine, and the genital, or reproductive, organs of male and female
humans, which together can produce a new human. (para 8-1)
The urinary system is specialized to remove certain nitrogenous waste products
from the circulating blood. These result from the body's use of proteins.
The major parts of the human urinary system are two kidneys, two ureters, one
On the concave, medial side of each kidney there is a notch called the hilus.
Through this notch pass the ureter and the NAVL which service the kidney.
If we compare the structure of the kidney with that of a cantaloupe, the structure
corresponding to the hard rind would be the renal cortex. The structure
corresponding to the edible flesh of the melon would be the renal medulla.
Corresponding to the hollow center (after removal of the seeds) would be the renal
sinus. The pyramids of the renal medulla form peaks called papillae, which empty
The functional unit of the human kidney is the nephron. Its main subdivisions are
The renal corpuscle is composed of the glomerulus and the renal capsule. Blood
enters by way of the afferent arteriole, passes through the tangled mass of
capillaries called the glomerulus, and leaves by way of the efferent arteriole.
Leaving the blood, fluid is first collected in the double-walled sac called the renal
The first coiled portion of the renal tubule is known as the proximal convoluted
tubule. The hairpin-shaped portion of the renal tubule is known as the renal loop
(of Henle). The second coiled portion is known as the distal convoluted tubule.
The distal convoluted tubules of several nephrons empty into a collecting tubule.
The urine is then passed from the collecting tubule at the papilla of the medullary
pyramid. Several collecting tubules are present in each pyramid. There is a
hollow sac within the sinus of the kidney called the renal pelvis. The ureter then
Ureters are tubes which connect the kidneys to the urinary bladder. The
mechanism used by ureters to move urine is peristalsis. (para 8-4)