In the ampulla, the epithelium modifications abruptly to low columnar without stereocilia, and the mucosa is in tall irregular folds. The fibrous lamina propria is very skinny and is surrounded by a wide layer of circularly arranged smooth muscle fibers and a much thinner layer of longitudinal fibers (Figure 13-49). The serosa is thin except on the point of the mesotubarium attachment, the place the fibrous tissue supports the vessels and nerves that accompany the duct within the spermatic cord. The nostrils, vestibules, and channels to the oral cavity are lined by stratified squamous epithelium.
The navicular and lateral cuneiform bones also articulate with the medial facet of the cuboid bone. The patella is largest sesamoid bone of the physique (seeFigure eight.16). A sesamoid bone is a bone that is included into the tendon of a muscle where that tendon crosses a joint. The sesamoid bone articulates with the underlying bones to forestall damage to the muscle tendon as a result of rubbing towards the bones during movements of the joint. The patella is discovered within the tendon of the quadriceps femoris muscle, the large muscle of the anterior thigh that passes throughout the anterior knee to attach to the tibia.
The ducts have a folded mucosa giving the lumen a wavy define. The gland tubules are surrounded by a delicate layer of smooth muscle fibers, and the mass of tubules is contained inside a firm will earn economic profits whenever: a connective tissue sheath which attaches it to the vesicular gland. The secretion is a homogeneous faintly acidophilic substance showing cracked in stained sections.
Trauma to the occiput can cause a fracture of the bottom of the cranium, referred to as a basilar cranium fracture. The basion-dens line as seen on a radiograph is the distance between the basion and the top of the dens, used in the diagnosis of dissociation accidents. The nuchal plane of the squamous half is ossified from two facilities, which appear concerning the seventh week of fetal life and shortly unite to form a single piece.
The urethra enters the penis on the posterior border of the pelvic girdle, the place a bulbous diverticulum extends laterally and posteriorly. From this point the penis extends anteriorly alongside the ventral wall inside the subcutaneous tissue to terminate on the ventrally elevated genital papilla. The exterior orifice of the urethra is on the tip of the glans, the club-shaped terminal end of the penis, which is roofed by a reflected fold of skin, the prepuce or foreskin. A small bone, the os penis, tasks slightly past the orifice. The testis is an oval physique, consisting of coiled tubules held together by connective tissue and lined by a troublesome membrane, the tunica albuginea. In a mature male, the testis weighs about eighty five mg, and measures 8.5 x 5 x 5 mm.
The lamina propria merges with the dense fibrous perichondrium of the pharyngeal, tracheal, and bronchial cartilages. The cartilages are hyalin aside from those of the epiglottis and arytenoids in which there are elastic and reticular fibers. The cartilages of the larynx are linked with each other and to adjacent buildings by strands of fibrous connective tissue and bundles of striated muscle. The open ends of the tracheal rings are joined by the graceful muscle tissue attached to the dorsal surface of the perichondrium.
Lymph flows from lymph capillaries into successively bigger vessels, thence into ducts that empty into veins within the neck. In the rat, lymph vessels unite to type two primary ducts one on both sides of the vertebral column . The small right duct opens into the proper superior vena cava on the junction or proper jugular and subclavian veins. The thoracic duct is the bigger duct on the left that opens into the junction of left subclavian and jugular veins. A pouchlike dilatation, the cisterna chyli, on the dorsal abdominal wall barely anterior to the kidneys, identifies the beginning of the thoracic duct. In the mouse solely certain subsidiary pathways such as that from the tail have been traced (Engeset and Tjötta, 1960).
Infrequently, the vas deferens and vesicular-gland duct be part of on one or both sides earlier than getting into the urethra. The body of the penis is made up of three lots of erectile tissue within heavy connective tissue membranes that additionally serve to connect the penis to the pelvic girdle. The skinny cavernosum urethrae, which is ventral to the urethra, expands proximally over the urethral diverticulum or bulb and extends distally a short distance between the heavier corpora cavernosa penis. The corpora cavernosa penis extend laterally and dorsally and virtually encircle the urethra.