Summary Course BBS2041
Pluis, CMH
,Case 1
Pluis, CMH
,Digestive or Gastro-Intestinal (GI) tract
• The digestive tract or GI-tract is the tract in which food is digested, absorbed and secreted (can be seen
long tube passing through the body)
• The function of the GI-tract is to move nutrients, water and electrolytes from the external milieu into th
internal milieu. It makes use of several processes to achieve this
• Ingestion is the intake of food into the digestive tract, usually via the mouth
• Propulsion includes swallowing (voluntary) and peristalsis (involuntary)
• Peristalsis include alternating waves of contraction and relaxation of muscles in the organ wal
rhythmic contractions)
• Segmentation mixes food with digestive enzymes
• Mechanical breakdown via teeth to increase the surface area and thereby preparing the food for
digestion (chewing and mixing with salvia)
• Digestion is the breakdown of food molecules into their building blocks with use of enzymes (chem
breakdown)
, Digestive or Gastro-Intestinal (GI) tract
• Absorption is the uptake of the building blocks, vitamins, water and minerals from the lu
of the GI-tract via either active or passive transport into the blood or lymphatic system
• Defecation is the elimination of indigestible substances via the anus in the form of feces
• Motility is the movement of material in the GI-tract as a result of muscle contraction
• Secretion is the release of substances secreted by GI epithelial cells into the lumen or EC
movement of water and ions from the ECF to the digestive tract lumen (opposite of
absorption)
Pluis, CMH
,Case 1
Pluis, CMH
,Digestive or Gastro-Intestinal (GI) tract
• The digestive tract or GI-tract is the tract in which food is digested, absorbed and secreted (can be seen
long tube passing through the body)
• The function of the GI-tract is to move nutrients, water and electrolytes from the external milieu into th
internal milieu. It makes use of several processes to achieve this
• Ingestion is the intake of food into the digestive tract, usually via the mouth
• Propulsion includes swallowing (voluntary) and peristalsis (involuntary)
• Peristalsis include alternating waves of contraction and relaxation of muscles in the organ wal
rhythmic contractions)
• Segmentation mixes food with digestive enzymes
• Mechanical breakdown via teeth to increase the surface area and thereby preparing the food for
digestion (chewing and mixing with salvia)
• Digestion is the breakdown of food molecules into their building blocks with use of enzymes (chem
breakdown)
, Digestive or Gastro-Intestinal (GI) tract
• Absorption is the uptake of the building blocks, vitamins, water and minerals from the lu
of the GI-tract via either active or passive transport into the blood or lymphatic system
• Defecation is the elimination of indigestible substances via the anus in the form of feces
• Motility is the movement of material in the GI-tract as a result of muscle contraction
• Secretion is the release of substances secreted by GI epithelial cells into the lumen or EC
movement of water and ions from the ECF to the digestive tract lumen (opposite of
absorption)
