Ch.23: Digestive System Part 1 Flashcards
The Two main groups of the digestive system
- alimentary canal (mouth, pharynx, esphagus, stomach, small intestine, and large intestine)
- accessory digestive organs (teeth, tongue, gallbladder, salivary glands, liver, and pancreas)
______________, also called gastrointestinal tract or gut, the continuous muscular tube that winds through the body from the mouth to the anus. It digest food and absorbs
Alimentary canal
__________ help produce a variety of secretions that help breakdown foodstuffs
accessory digestive organs
The proccessing of food by the digestive system involves six essential activities:
Ingestion Propulsion (swallowing/peristalsis) Mechanical breakdown (segmentation) Digestion Absorption (blood/lymph) Defecation
Layers of the peritoneum on the abdominopelvic cavity
- visceral peritoneum(external surface of digestive organs)
- parietal peritoneum(lines the body wall)
- peritoneum cavity (lubrication)
- Mesentery (double layer of peritoneum, provides routes for blood vessels, lymphatics and nerves, holds organs in place and store fat)
Layers of the GI Tract
- Mucosa
- SubMucosa
- Muscularis externa
- Serosa (Visceral Peritoneum)
Three Major Functions of the Mucosa
- secretes mucus, digestive enzymes and hormones
- absorbs the end products of digestion
- protect against infectious disease
Three sublayers of Mucosa are:
- Lining epithelium (simple columnar epithelium, goblet cells)
- Lamina propria (nourish and absorb MALT)
- Muscularis mucosae (smooth muscle, movements)
Function of Submucusa and what it contains:
- areolar connective tissue, rich supply of blood and lymphatic vessels
- enable the stomach to regain its normal shape after a large meal
Function of The Muscularis Externa and what it contains:
- responsible for segmentation and persistalsis
- circular muscles and longitudinal muscles
Function of Serosa:
- also called visceral peritoneum
- a single layer of squamous epithelium
Intrinsic control:_______ _______ form ganglia and plexuses that communicate with each other to regulate digestive activity.
Enteric Neurons
Extrinsic control:
- regulated by the autonomic nervous system
- linked to the CNS Sym& paraSym
- sym. decreases Gi tract motlity, secretionand hunger
- Parasym. vagus nerve, Increase
_______, occupies the floor of the mouth, is composed of interlacing bundles of skeletal muscle fibers. During chewing it grips the food and constantly repositions it between the teeth. Mixes the food with saliva forming it in to a bolus.
Tongue
_______ ______ roughen the tongue surface, lick semisolids food, such as ice creams, provide friction for manipulating foods
filliform papillae
Function of the Saliva
- cleanse the mouth
- dissolves food chemicals so they can be tasted
- moistens food and helps compact it into a bolus
- contains enzymes that begin the chemical breakdown of starchy food
Three types of salivary glands:
- parotid gland
- submandibular gland
- sublingual gland
Two types of secretory cells:
- Serous cells ( produce watery secretion containing enzymes, ions, and solution)
- Mucous cells (produce mucus)
Composition of Saliva:
- 99.5% water and .5% Solutes
- slightly acidid pH (6.5 to 7.00)
- salivary amylase (polysacchrides) and lingual lipase (triglycerides)
- lysozyme (prevent tooth decay)
- IgA and defensins
________ ________, also called milky, or baby teeth. 20 milk teeth have emerged
Deciduous teeth
Permanent teeth have _____ in a full set
32`
The __________ prevents the food from entering into the wrong tube
Epiglottis
Characteristics of the Esophagus:
- muscular tube, 10 inches
- pierces the diaphragm at the esophageal hatius
- no chemical digestion
- fibrous adeventitia
_________, first symptom of gastroesophageal reflux disease, is the burning radiating substernal pain that occurs when stomach acid regurgitates into the esphagus
heartburn
Digestive Process: Mouth to Esophagus:
Mouth
- ingest,
- begins mechanical breakdown by chewing,
- initiates propulsion by swallowing,
- starts chemical breakdown (polysacchrides)
As food enters the mouth, its mechanical breakdown begins with __________, or chewing. It’s partly voluntary and partly reflexive.
Mastication
_____________, or swallowing is a complicated process that involves coordinated activity of over 22 seperate muscle groups. Two major phases: the buccal and the pharyngeal-esophageal.
Deglutination
