🌸Digestive System Chapter 18 Anatomy🌸

• Mouth to anus, 9m. (29ft) long
• Main organs(inside or surrounding GI tract)

  mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anal canal
• Accessory Organs of the mouth:

  teeth, tongue, salivary glands
• Accessory organs of the pharynx:

  tonsils
• accessory organs of the small intestine:

  liver, gall bladder, pancreas
• Accessory organs of the large intestine:

  vermiform appendix
• The digestive tube has central hollow space called lumen
• The digestive tube is the GI tract muscular tube from mouth to anus
• The digestive tube is formed by four layers
• The four layers of the digestive tube are mucosa, submucosa, muscularis, serosa
• Ingestion is the process of taking food into the mouth, starting it on its journey through the digestive tract
• Digestion is a group of processes that break complex nutrients into simpler ones, thus facilitating their absorption; mechanical digestion physically breaks large chunks into small bits; chemical digestion breaks molecules apart
• Mobility is the movement by the muscular components of the digestive tube, including processes of mechanical digestion; examples include peristalsis and segmentation
• Secretion is the release of digestive juices (containing enzymes, acids, bases, mucus, bile, or other products that facilitate digestion); some digestive organs also secrete endocrine hormones that regulate digestion or metabolism of nutrients
• Absorption is the movement of digested nutrients through the gastrointestinal(GI) mucosa and into the internal environment
• Elimination is the excretion of the residues of the digestive process (feces) from the rectum, through the anus; defecation
• Regulation is the coordination of digestive activity( motility, secretion, other digestive processes)
• The digestive tube is formed by four layers
• The four layers that form the digestive tube are mucosa, submucosa, muscularis, serosa
• Mucosa is involved in mucous secretion.
• Mucosa is a tough stratified squamous epithelium or delicate simple epithelium.
• Submucosa is a connective tissue layer.
• Muscularis is 2-3 layers of smooth muscle.
• Peristalsis and segmentation is part of muscularis.
• Peristalsis is a wave-like motion which pushes food down the GI tract.
• Segmentation breaks apart chunks of food and mixes in digestive juices.
• Serosa is a serous membrane covering outside of abdominal organs.
• Serosa attaches digestive tract to wall abdominopelvic cavity by forming skin-like folds called mesenteries.
• Roof of the mouth is formed by hard palate.
• Hard palate -portions of maxillary and palatine bones.
• Soft palate :arch-shaped muscle separating mouth from pharynx.
• Uvula -projection from soft palate.
• Uvula helps in speech and swallowing.
• Type of teeth are incisors, canines, premolars, molars.
• Saliva is exocrine gland secretion.
• Watery secretion from saliva contains salivary amylase, sodium bicarbonate, mucus
• salivary amylase -enzyme which begins digestion of complex carbs.
• Sodium bicarbonate -NaHCO3, neutralizes bacteria-produced acids.
• Mucus -lubricates food by mixing during chewing [mastication].
• Parotid is the largest salivary gland.