Please enable JavaScript.
Coggle requires JavaScript to display documents.
Cuesta-Baltazar, The Digestive System - Coggle Diagram
Cuesta-Baltazar, The Digestive System
disorders
- Ulcers
- Inflammatory Bowl disease
- constipation Hemorrhoids
- Gastroesophageal reflux disease (GERD)
Anatomy
Gastrointestinal Tract (GI Tract):
- A tube within a tube, open system
- Continuous tube running from mouth to anus for food
GI Tract
Mucosa:
- Mucous Membrane:
Produces mucus for reduction of friction and Protections
-Epithelium
- varies in location
- Nonkeratinized stratified squamous in mouth, esophagus and anus, protection against friction
- Simple columnar in intestine for absorption and secretion
-Lamina Propria:
- Areolar connective tissue
- Contains blood and lymphatic vessels and lymph nodes
-Muscularis mucosa: - 2 thing layers of smooth muscle
Submucosa:
- Areolar connective tissue containing major blood vessels
- many elastic fiber
- submucosal supply
- glands and lymphatic tissue
Muscularis Layer:
- 2 layers of smooth muscles to allow peristalsis and segmentation
- Inner circular:
layer - squeeze, decrease size of lumen; in some areas act as sphincter or valves
-Outer longitudinal layer: -Shortens intestine
- mouth, pharynx, superior esophagus, and anal
-Sphincter- Voluntary muscle
- External anal sphincter is skeletal muscle
-Myenteric plexus - nerves
Serosa:
- Outer covering of the GI tract
- Serous membrane:
Composed of thin layer of areolar connective tissue and simple squamous epithelium
- Produces serous fluid for lubrication
Mouth:
- Opening into Oral cavity
- Oral cavity:
Area enclosed by the teeth and lips
- Contains salivary glands, tonsils, and tonsils
-Mechanical digestion, by teeth bu mastication -
Mixing of food with saliva by the tongue to make bolus
-Chemical digestion by saliva produced by salivary glands, digestion of starch begins
- Mucosa produces mucus to coat bolus for easier transports - Initiates deglutition
-Tongue allows sense of taste -Immune function by palatine tonsils
Pharynx:
-Oropharynx:
located posteriorly to mouth; passage for food, water, and air
- Laryngopharynx:
-Inferior to oropharynx
- Involved in deglutition, forcing bolus from mouth to esophagus
Esophagus:
- collapsible tube runs from the pharynx to stomach pass through diaphragm
-Located posteriorly to the trachea
- food transported by peristalsis
- No digestive function, only a passage for food and water
Stomach:
Food enters at cardioesophagal sphincter
-Food empties into duodenum of small intestine at the pyloric sphincter
-Rugae:
Internal folds of stomach mucosa
- J-shaped, acts as storage tank for food
- food mixes with gastric juice to make chyme
-Mechanical digestion by churning of stomach
- Chemical digestion
- break down of proteins begins
- Regions of stomach :
-Cardiac region- near heart
-Fundus dome shaped, filled with gas
- Body-main portion
-Pylorus-funnels shaped end
-Pyloric sphincter -controls food leaving stomach and entering small intestine
- Only absorption occurs is water, alcohol, some vitamins, and aspirin
Small intestine:
-muscular tube extending from the pyloric sphincter to the ileocecal valve
- Chemical digestion of fat begins
- most chemical digestion takes place of all foods by enzymes produced by accessory organs
- Site of absorption into blood and lymphatic vessels
- Peristalsis and segmental movement mix chyme with digestive enzymes
- Regions of SI:
- Duodenum 1st portion attached to stomach; chemical digestion
-Jejunum - end portion, connected to cecum, some absorption
- Villi of SI- finger like structures that increase surface area of absorption
-Large Intestine:
-site of absorption of water and electrolytes; produces vitamins.
-Eliminates indigestible food from body as feces.
-Doesn't participate in digestion but resident bacteria digest remaining nutrients; causes gas or flatuation (farts).
- Regions of Li:
Cecum 1st out pocketing of the LI, attached to small intestine; site of appendix attachment.
- colon ascending, transverse, descending, and sigmoid colon.
- Rectum stores feces until it's defecated
- Features of LI:
- contains tenia coli
-Haustra-bulges or pockets along LI
-Movement is slow and sluggish in the LI except for 3-4 mass peristaltic movement per day toward rectum
Anus:
- Eliminates feces from rectum to exterior
- Defecation controlled by sphincters;
-Internal sphincter: Made of involuntary smooth muscle
-External Sphincter: voluntary skeletal muscle
- presence of feces in rectum triggers defecation
Digestive accessory organs:
-Aid in digestion but not a pathway for food
-Involved in mechanical and chemical digestion
-found in mouth, stomach, and the intestine; also includes liver, pancreas, and gallbladder
Teeth:
-Hardest substance in body; functions to mechanically break down food into smaller pieces
Anatomy:
-Enamel-hardest outer layer
-Dentin-middle layer of bone-like living tissue under enamel
-pulp-softer inside structure; contains nerves and blood vessel
-Supporting ligament:
connective tissue that attaches teeth to jaw bone
-Gingivi-gums
Regions of teeth:
-Crown- part of tooth above gums
- Root-anchored under gums
Types of teeth:
-Deciduous- baby teeth
-Permanent- adult teeth
-Incisors-most anterior, for cutting
-Cuspids/canines- lateral to incisors; for tearing/shredding
-Premolars/molars- sides and back teeth; grinding
Salivary glands:
- Produces saliva(mix of 99% water and mucus0 to moisten food into bolus
-Contains salivary amylase-digest starch
- 3 pairs of glands: Parotid, submandibular, sublingual
Gastric Glands:
-Goblet cells- produces mucus(provides protective lining against stomach acid)
- Chief cells produce pepsinogen
-Pepsinogen in presence of Hydrochloric acid, converts pepsinogen to pepsin
- Pepsin-protein digesting protein enzyme in stomach
- Parietal cells-produce HCL and Intrinsic factor
-Intrinsic factor
-Needed for absorption of vitamin B12 in stomach
Intestinal Glands:
- Secrete intestinal juice
- Duodenal glands:
-Alkaline mucus to neutralize stomach acid
- Enzymes in duodenum digest all food groups but requires neutral PH to work
Pancreas:
- Produces digestive enzymes:
-Lipase(digest fats)
-Pancreatic amylase(digest carbs)
- Trypsin and chymotrypsin (Digest proteins)
- Releases enzymes into duodenum
- Regulated blood sugar by producing insulin
Liver:
- Largest gland; made of 4 lobes
- Falciform ligament holds lobes to abdominal wall
- Functions for storage for glycogen, fat soluble vitamins and iron
- Produces bile(emulsifies fat)
- Removal of drugs, alcohol, and hormones
Gallbladder:
-Pear-shaped organ; located on the underside liver on the right side of abdominal cavity
- Stores bile and released into duodenum when needed
Functions
Ingestion:
- Taking in food through mouth
-Propulsion and segmentation
- Peristalsis
-Propulsion by contraction and relaxation of smooth muscles lining the alimentary canal
Digestion:
-Process of breaking down larger food molecules into smaller molecules
-Mechanical digestion
- Physical breakdown of food by cutting and grinding
-Chemical Digestion
- requires enzymes
Absorption:
-Transport of digested end produce into blood and lymph through the walls of the GI tract
-
-