Question | Answer |
Where is the locations of the digestive tract? | Includes series of hollow organs extending from mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum and anus which form the gastrointestinal (GI) tract. |
What is the function of the digestive tract? | Getting nutrients into the body. |
What are the features of the digestive tract? | Includes four accessory organs: the salivary glands, liver, gallbladder and pancreas. |
Name the four layers of the GI tract. | Mucosa, submucosa, muscularis, serosa. |
What is the function and location of mucosa? | Innermost tissue layer (the mucous membrane in contact with the lumen) All nutrients must cross the mucosa to enter the blood. |
What is the function and location of submucosa? | Layer of connective tissue containing blood vessels, lymph vessels, and nerves. Components of food that are absorbed across the mucosa enter the blood and lymph vessels. |
What is the function and location of muscularis? | The third layer. Responsible for motility or movement. Consists of two or three sublayers of smooth muscle. |
What is the function and location of serosa? | Connective tissue that surrounds and protects the other three layers and attaches the digestive system to the walls of the body cavities. |
What are thee five basic processes of the digestive tract? | Mechanical processing and movement, secretion, digestion, absorption, elimination. |
What is mechanical processing and movement? | Chewing breaks food into smaller pieces and two types of movement (motility) mix the contents of the lumen and propel it forward. |
Define secretion. | Fluid, digestive enzymes, acid, alkali, bile and mucus are all secreted in the GI tract at various places. Several hormones that regulate digestion are secreted into the bloodstream. |
Define digestion. | The contents of the lumen are broken down both mechanically and chemically into smaller and smaller particles, culmination in nutrient molecules. |
Define absorption. | Nutrient molecules pass across the mucosal layer of the GI tract and into the blood or lymph. |
Define elimination. | Undigested material is eliminated from the blood to the anus. |
What are two types of motility that aid the digestive processes? | Peristalsis and segmentation. |
What does peristalsis do to aid the digestive process? | Propels food forward. |
What does segmentation do to aid the digestive process? | Mixes food. |
How and where nutrients are absorbed? | Nutrients are absorbed by the small intestine. The folds, villi and microvilli enlarge the surface area of the small intestine by more than 500 times increasing the ability to absorb nutrients. |
What is mechanical digestion. | Involves physically breaking the food into smaller pieces. It begins in the mouth as the food is chewed. |
What is chemical digestion? | Involves breaking down the food into simpler nutrients that can be used by the cells. Begins in the mouth when food mixes with saliva. |
What is the pancreas's role in digestion? | Produces and secretes several products directly into ducts leading to the digestive tract and secretes hormones into the bloodstream. |
What is the liver's role in digestion? | To facilitate the digestion and absorption of lipids by producing bile. |
What is the gallbladder's role in digestion? | It concentrates the bile produced by the liver by removing most of the water from the bile and then stores the concentrated bile until it's needed. |
How does the endocrine and nervous systems role in regulation of the digestive system? | They regulate digestion according to both volume and content of food. |
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