i 3 2 
MAMMALIAN ANATOMY 
3. Male Genital Organs. —Note location of the testes in the 
scrotal sacs and the muscular and peritoneal elements which 
enter into the walls of the latter and enclose the testes themselves. 
The removal of the visceral peritoneal layer discloses the testis 
in its capsule, and its associated structure, the epididymis, the 
tubules of which form the connection between the testis and 
the ductus deferens through which its secretion is discharged. 
Note the course of the ductus deferens through the inguinal canal 
as one component of the spermatic cord. Demonstrate the rela¬ 
tion of the ductus deferentia, seminal vesicles, and prostate and 
bulbourethral glands to each other and to the urethra. The penis 
is characterized by the development of three columns of erectile 
tissue ( i.e ., tissue containing large blood sinuses, which, when 
distended with blood, produce the erect condition necessary to 
copulation) as follows: The median corpus cavernosum urethrae 
in the posterior region, ending in the enlargement known as the 
glans, and the two lateral corpora cavernosa penis, all withdrawn 
distally within the prepuce, when the penis is not in a state of 
erection. Note also certain muscular elements which arise from 
the ischium and are inserted into the penis. 
B. STRUCTURE. 
1. The Kidney. 
Macroscopic Study. —Examine externally a simple kidney such 
as that of a rabbit or guinea pig, carefully removing the loose 
packing of fat and areolar tissue in which it is imbedded. Note 
the tough capsule covering it, and the depression or hilus through 
which the ureter and the renal blood vessels pass. Cut the kidney 
by a longitudinal section passing through the hilus and identify 
the following regions and parts: The granular cortex; the medulla, 
with striated appearance converging from the cortex to the apex 
of a large papilla; the cavity or pelvis into which the papilla 
projects embraced by the expanded funnel-shaped calyx from 
which the ureter leads; and the veins and arteries outside of the 
calyx and ureter, within the sinus of the kidney. Since the ureter, 
calyx, and blood vessels are held together within the sinus by a 
packing of fatty areolar tissue, this must be removed in order to 
