FERTILIZATION Sperm capacitation ( 23-1 ) Fertilizing sperm must complete maturation and capacitation before sperm-egg fusion can take place. Sperm released from the testis and entering the epididymal duct display circular motion . After a 2-week maturation process during epididymal…
Development of the female reproductive tract The reproductive tract develops through the differentiation of wolffian ducts (male reproductive tract anlage) and müllerian ducts (female reproductive tract anlage). The female reproductive system consists of the ovaries , the ducts (oviduct, uterus…
DEVELOPMENT OF THE GONADS ( Primer 21-A ) An important aspect of gonadogenesis is the migration of cell precursors of the male and female gametes from the primary ectoderm into the wall of the yolk sac to become extra-embryonic .…
THE TESTES ( 20-1 and 20-2 ) The testes are paired organs located in the scrotum, outside the abdominal cavity. This location enables maintenance of the testes at a temperature 2 o C to 3 o C below body temperature.…
THYROID GLAND Development of the thyroid gland The thyroid gland (Greek thyreos , shield; eidos , form) develops as a median endodermal downgrowth at the base of the tongue. A transient structure, the thyroglossal duct , connects the developing gland…
HYPOPHYSIS ( 18-1 ) The hypophysis (Greek hypo , under; physis , growth), also known as the pituitary gland , consists of two embryologically distinct tissues: 1. The adenohypophysis , the glandular epithelial portion. 2. The neurohypophysis , the neural…
STRUCTURE OF A SALIVARY GLAND ( 17-1 and 17-2 ) We start the discussion by reviewing the general organization and function of a salivary gland, in particular its branching ducts (see Box 17-A ). An initial discussion concerning the general…
SMALL INTESTINE ( 16-1 to 16-3 ) The 4- to 7-meter-long small intestine is divided into three consecutive segments: 1. Duodenum . 2. Jejunum . 3. Ileum . The duodenum is about 25 cm in length, is mainly retroperitoneal and…
Mouth (oral cavity) The oral cavity is the entrance to the digestive tube. Ingestion, partial digestion and lubrication of the food, or bolus, are the main functions of the mouth and its associated salivary glands. We study the salivary glands…
THE KIDNEYS ( 14-1 ) The urinary system consists of paired kidneys and ureters and a single urinary bladder and urethra. Each kidneys has a cortex (subdivided into outer cortex and juxtamedullary cortex) and a medulla (subdivided into outer medulla…