Anatomy and Physiology of the Digestive System Chapter 13: The Digestive System and Nutrition Lesson 13.2 Anatomy and Physiology of the Digestive System

Activities of Digestion (1) ingestion getting food into the body (2) propulsion - Peristalsis moving food along GI tract (3) mechanical breakdown breaks food into smaller pieces- chew your food! increases surface area of food-increases efficiency

Activities of Digestion (4) chemical breakdown also known as digestion – this is the definition of digestion enzymes –make digestion faster (amylase, pepsinogen, protease, lipase, etc…) (5) absorption digested food particles moved into blood (6) defecation -poop

Activities of Digestion

Layers of the Alimentary Canal mucosa innermost layer adjacent to lumen- epithelial tissue- absorption Submucosa –lots of blood vessels below mucosa

Layers of the Alimentary Canal muscularis externa – causes peristalsis circular muscle longitudinal muscle serosa – connective tissue- keeps shape & protects outermost layer peritoneum visceral parietal LUMEN submucosa mucosa

Layers of the Alimentary Canal

Review and Assessment True or False? 1. Mechanical breakdown decreases the surface area of food. 2. The mucosa is adjacent to the lumen. 3. Peritoneum is serosa. 4. In absorption, digested food moves into the blood.

Digestive Organs and Their Functions

The Oral Cavity Lips- keep food in Tongue – moves food to teeth Cheeks-keep food in palate Hard-separate nasal from oral cavities Soft-moves to accommodate swallowing

The Nasal Cavity passageway for air uvula hangs from soft palate keeps food out of nasal cavity when swallowing

Teeth and Gums Gum- protect tooth roots and steady teeth in jaw bones – teeth constantly move gingiva teeth Deciduous- baby teeth (lose them) permanent Incisor-slicing Canine-tearing Molar-grinding

Anatomy of the Tooth

Salivary Glands parotid submandibular Sublingual saliva Together provide saliva based on need. saliva water enzymes –break down food (amylase)

Pharynx Nasopharynx-air Oropharynx-directs food to esophagus Laryngopharynx-splits resp. & dig. systems glottis Epiglottis-Heimlich maneuver

Esophagus connects pharynx to stomach peristalsis muscle contraction changes size of tube food is moved through GI tract

Stomach regions three layers of muscle cardia fundus body pyloric region three layers of muscle -all of this helps the stomach churn

Lining of the Stomach gastric gland mucus-secreting cells parietal cells-secrete HCl chief cells-secrete pepsinogen (& renin) enteroendocrine cells-secrete peptide hormones (full feeling)

Chemical Reactions in the Stomach protein-digesting enzymes (pepsinogen) chyme formation- bolus- allows smoother travel through intestines stomach contractions

Review and Assessment Match these words with 1–4 below: canine, fundus, parotid, esophagus. 1. region of stomach 2. connects pharynx to stomach 3. a type of tooth 4. a type of salivary gland

Small Intestine segments lining Duodenum- connection to stomach. Place of bile and pancreatic juice introduction Jejunum – absorption Ileum- connection to the colon via cecum lining Villi – finger-like (also known as microvilli) increase surface area intestinal crypts- produce mucus and secretions to move chyme along the alimentary canal

Small Intestine chemical breakdown absorption into the blood emulsification by bile break down by enzymes absorption into the blood from capillaries to the blood lacteal to lymph vitamin B12

The Liver functions of the liver- bile production maintains nutrients in blood converts one nutrient to another stores nutrients inactivates toxins hepatic portal vein- cleansed blood back to the circ. system parts of the liver Lobules- divisions Hepatocytes-cells blood vessels bile canaliculi- direct bile to ducts bile salts

Liver and Gallbladder

The Gallbladder functions of the gallbladder stores bile produced by liver releases bile when fat-containing chyme is in duodenum http://theawkwardyeti.com/comic/gall-bladders-day/

Pancreas pancreatic juices- exocrine glucose regulation- endocrine contain digestive enzymes glucose regulation- endocrine beta cells–insulin alpha cells–glucagon

Large Intestine regions Cecum- “garbage dump” first place to receive spent chyme colon Ascending transverse descending sigmoid All used to reabsorb water

Rectum, Anal Canal, and Anus sphincters internal external Fecal material storage For control

Review and Assessment Match these words with 1–4 below: jejunum, sigmoid, beta cells, gallbladder. 1. a region of the colon 2. a region of the small intestine 3. stores bile 4. produce insulin