| What are the steps of the Digestive Process? | Ingestion
Digestion
- Mechanical Digestion
- Chemical Digestion
Absorption
Elimination/Defecation |
| Describe Ingestion | occurs in the mouth, intake of food. |
| how does dood move through the digestive tract? | Through peristalsis (and propulsion) |
| Define Peristalsis | Peristalsis is the major means of propulsion/movement of food.
Adjacent segments of alimentary tract organs alternately contract and relax, moving food along the tract distally. |
| What action does the image show? | the picture shoes food or bolus being moved through contractions and relaxations
Peristalsis |
| What is Mechanical Digestion? | Mechanical digestion describes chewing (mastication), stomach churning, and segmentation.
Prepares food for chemical digestion |
| Define segmentation | Segmentation is rhythmic local constrictions of intestine. Mixes food with digestive juices.
Nonadjacent segments of alimentary tract organs alternately contract and relax, moving food forward then backward. Food is mixed and slowly propelled. |
| What is Chemical Digestion? | Chemical digestion occurs in the mouth, stomach, and small intestine.
Chemical digestion is where complex molecules are broken down into chemical components.
ex: our saliva helps break down food. |
| Define absorption | Absorption is the transport of digestion nutrients into the blood. |
| Define Defecation | also known as elimination, the elimination of indigestible substances as feces |
| What is found in the Mucosa Layer? | a. Epitheliunmn
b. Lamina Propia
c. Lymphatic vessel
d. Muscularis mucosae |
| What occurs in the epithelium of the Mucosa layer? | - exocrine cells and glands secrete digestive juices (enzymes) and (from goblet cells) mucous
- endocrine cells and glands secrete hormone into blood stream |
| Define Lamina Propia | Lose to dense connective tissue
contains numerous blood and lymphatic capillaries |
| Define Muscularis Mucosae | A thin layer of circular and longitudinal smooth muscle, maintains tone when tube is empty.
Stimulated by the sympathetic nervous system. |
| What is found in the submucosa layer? | Submucosal nerve plexus |
| What is found in the Muscularis Externa Layer? | a. oblique muscle
b. circular smooth muscle
c. longitudinal smooth muscle |
| Responsibility of circular and longitudinal smooth muscle? | responsible for peristalsis |
| What are the muscle layers (oblique muscle) separated by? | myenteric nerve |
| Define the Serosa Layer | The serosa is a connective tissue layer connected to mesenteries (connective tissue sheets) which themselves connect to connective tissue that lines the adominal cavity. |
| Name the layers of the digestive tract | From lumen outward...
Mucosa
Submucosa
Muscularis externa
Serosa |
| l
Label the colored portion | Mucosa layer
- epithelium
- lamina propria
- muscularis mucosae |
| Label the colored portion | Submucosa |
| Label the colored portion | Muscularis externa
- circular smooth muscle
- longitudinal smooth muscle |
| Label the colored portion | Serosa
- areolar connective tissue
- epithelieum |
| Label the colored portions | blue portion: myenteric plexus
green: submucosal plexus |
| Define gastric gland | mostly exocrine glands
located beneath gastric pits within gastric mucosa (mucous membrane one stomach)
contains many cells |
| What cells are found in a gastric gland | - mucous cells - parietal cells - chief cells |
| Define mucous cells | mucous neck cells secret a special mucous |
| Define Parietal cells | Parietal (oxyntic) cells secrete hydrochloric acid and gastric intrinsic factor |
| Define chief cells | Chief (zykogenic) cells secrete pepsinogen |
| Define pepsinogen | Pepsinogen is activated to pepsin when it encounters acid in the gastric glands. |
| What tissue is found in the stomach? | simple columnar epithelium |
