Digestive system worksheet
The digestive system is a long tube running from mouth to anus, consists of the following parts: mouth, ______, ______, ______, ______, rectum, anus. In addition two accessory organs add secretions to the digestive tract: the ______and the ______. There are exchanges between blood and the digestive system contents, in two directions: ______of the “tools” for digestion (primarily ______which break down food into its simplest components), and ______of nutrients in the form of amino acids, simple sugars, nucleic acids and fats. Blood leaving the digestive system does not return immediately to the heart, but first passes through the ______vein which takes it to the ______.
Food remains for approximately ______hours in the stomach, and reaches the small intestine after ______hours and the large intestine after ______hours. Total transit time (mouth to anus) varies from ______to ______hours. The contents are propelled along the digestive tract by a wave of rhythmic contractions (relaxation ahead of a food bolus, contraction behind it); this is termed ______.
In the mouth the ______glands produce saliva, which begins the process of digestion because it contains an enzyme which is called salivary ______; this name is derived from the fact that it breaks down ______to form the disaccharide ______. There are _____ deciduous teeth (milk teeth, baby teeth) and ______adult teeth. The stomach secretes two substances, which are particularly important in breaking down food; these are ______and the enzyme ______, which is secreted as the inactive precursor ______. In addition it secretes mucus whose main function is ______.
The pancreas has two divisions, endocrine (secreting into the blood) and ______(secreting into the small intestine). It has two important functions in digestion: it secretes ______, which neutralises stomach acid, and enzymes. These substances are secreted from the ______(endocrine/exocrine) division. The liver is divided into hexagonal lobules, through which blood travels from the ______vein to the ______vein.
The small intestine is about ______long in total and is made up of three sections, the ______, the ______and the ______; of these, most of the absorption takes place in the ______and ______. The large intestine absorbs water from its contents and the contents are then known as ______. The contents are propelled along the large intestine by waves of contraction known as ______.
Although our fluid intake may be low, large movements of water nevertheless take place across the wall of the digestive tract. On a typical day we secrete ______of water into the digestive tract and absorb ______, leaving about ______of water in the faeces.