In this article we will discuss about the structure of adult hookworm. This will also help you to draw the diagram and structure of hookworm.
i. Adult hookworms have slightly stout, more or less cylindrical body with a curved anterior end, dirty rust colour and covered with tough cuticle. The fully grown male worms measure about 8-11 mm long and the female worms measure about 10-13 mm long.
ii. The anterior end is bent dorsally and bears a large buccal capsule. This bend is in the same direction as the general body curvature.
iii. The oral aperture is not terminal but directed towards the dorsal surface.
iv. The large and conspicuous buccal capsule is lined with a hard substance which bears 6 teeth; 4 hook-like on the ventral surface and 2 knob-like on the dorsal surface.
v. There are five glands which are concerned with the digestive system, one of them, called the oesophageal gland, secretes a ferment which prevents the coagulation of blood. Ventrolaterally in the buccal capsule open a pair of amphidial or cephalic glands which extend backward almost to half the length of the worm. In the wall of the oesophagus are embedded a single dorsal and two subventral digestive glands.
vi. The buccal capsule opens into the oesophagus which lined with cuticle has a tri- radiate lumen. The oesophagus continues posteriorly as straight intestine which opens into a short rectum. In female the rectum opens subterminally through the anus. But in case of male the rectum along with the ejaculatory duct opens posteriorly into a cloaca (Fig. 12.1).
vii. A short distance behind the head is an excretory pore through which open a pair of slender cervical glands or excretory glands. The excretory system comprises of a carrying cell, a suspensory cell and a pair of tubules extending from the buccal capsule to almost the posterior end of the worm.
viii. There is a circum-oesophageal nerve ring slightly ahead of the excretory pore. A pair of lateral cervical papillae are present behind the circum-oesophageal nerve ring.
ix. Sexes are separate and are distinguished by a number of features. The male is smaller than female and the posterior end carries a copulatory bursa. The female has a pointed posterior end.