15 - 1 chapter 25,26,27 digestion and nutrition. 15 - 2 general characteristics of the alimentary...
TRANSCRIPT
15 - 1
Chapter 25,26,27Digestion and Nutrition
15 - 2
General Characteristics of the Alimentary Canal
• Approximately 27 feet• Structure of the wall – 4
layers– Mucosa - protects– Submucosa- nourishes– Muscular – propel food – Serosa - secretes serous
fluid – lubrication• Movements of the tube
(peristalsis) – Mixing– Propelling
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
15 - 3
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Peristalsis
15 - 4
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Mouth - oral cavity• Cheeks and lips• Tongue – held down by frenulum• Palate
– Hard palate– Soft palate
• Teeth– Primary– Secondary– Incisors, cuspids, bucuspids, molars
15 - 5
teeth
15 - 6
Salivary Glands• Salivary secretions
– Serous cells– Amylase - digests carbohydrates– mucous
• Major salivary glands– Parotid– Submandibular– Sublingual
15 - 7
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Salivary glands
15 - 8
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
pharynx• Structure
– Nasopharynx– Oropharynx– Laryngopharynx
• Swallowing mechanism– Food mixed and forced into pharynx– Sensory receptors trigger swallowing reflex– peristalsis
15 - 9
Esophagus• Collapsible passageway leading to stomach
• Mucous glands
• Esophageal sphincter
15 - 10
The stomachCopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
15 - 11
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Stomach• Parts of the stomach
– Cardiac, fundic, body, pyloric– Pyloric sphincter
• Gastric secretions - mucus, pepsin, hydrochloric acids, intrinsic factor
• Regulation of gastric secretions– Parasympathetic impulses, gastrin (increases
secretions of gastric glands
• Gastric absorption• Mixing and emptying actions (chyme)
15 - 12
pancreas• Produces pancreatic juices which aid in
digestion
• Located in association with the small intestine
• Structure of the pancreas– Acinar cells – produce pancreatic juices.– Travel through Pancreatic duct– Controlled by Hepatopancreatic sphincter
15 - 13
• Pancreatic juice– Digest organic compounds– Amylase, lipase, chymotrypsin (trypsin),
carboxypeptidase, nucleases
• Regulation of pancreatic secretions– Secretin - stimulates release of pancreatic fluid– cholecystokinin
15 - 14
The PancreasCopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
15 - 15
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
15 - 16
The liver• Location
• Structure– Hepatic lobules, sinusoids– Hepatic portal vein– Kupfer cells
• Function - metabolism of glucose from noncarbohydrates, storage of vitamin D, filter blood, digestion
15 - 17
Bile• Functions of bile salts-emulsify fat• Made in liver• Gallbladder - stores bile • Composition of bile- water, bile salts, bile
pigments, cholesterol, electrolytes• Regulation of bile release -
cholecystokinin, hepatopancreatic sphincter
Small Intestine• Function
– Receives pancreas and liver secretion, completes digestion of nutrients, absorbs products of digestion, transports residues to large intestine.
• Parts of the small intestine– Duodenum, jejunum, ileum– Duodenum – shortest, fixed portion– Suspended by mesentery
• Small intestinal wall– Lined with villi – connective tissue and capillaries– 4 layers
• Secretions– Goblet cells – secrete mucous– Intestinal gland – watery fluid– Digestive enzymes
• Regulation of secretion – mechanical and chemical stimulation – release of mucous• Absorption of nutrients
– Monosacharides – facilitated diffusion– Amino acids – active transport– Fatty acids – encapsulated then absorbed
• Movement - peristalsis
15 - 19
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
15 - 20
Large intestine• Parts – ascending colon, transverse colon,
descending colon• Structure of wall
– 4 layers– No villi
• Functions - reabsorption of water from chyme• Movements accomplished by peristalsis• Feces – waste products
– Contain undigested material, mucous, water, bacteria– Color – bile salts– Smell – bacterial action
15 - 21
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
15 - 22
Nutrition and NutrientsA. Nutrition is the process by which the body
takes in and uses nutrients.
B. Essential nutrients are those that cannot be synthesized by human cells.
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
15 - 23
Carbohydrates• Sources
• Utilization
• requirements
15 - 24
Lipids
• Sources
• Utilization
• Requirements
15 - 25
proteins• Sources
• requirements
15 - 26
vitamins• Fat soluble
• Water soluble
15 - 27
minerals• Characteristics
• Major minerals
• Trace elements