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Transcript
Chapter 25,26,27
Digestion and Nutrition
15 - 1
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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
15 - 2
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Peristalsis
15 - 3
CopyrightThe 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 - 4
teeth
15 - 5
Salivary Glands
• Salivary secretions
– Serous cells
– Amylase - digests carbohydrates
– mucous
• Major salivary glands
– Parotid
– Submandibular
– Sublingual
15 - 6
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Salivary glands
15 - 7
CopyrightThe 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 - 8
Esophagus
• Collapsible passageway leading to stomach
• Mucous glands
• Esophageal sphincter
15 - 9
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
The stomach
15 - 10
CopyrightThe 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 - 11
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 - 12
• Pancreatic juice
– Digest organic compounds
– Amylase, lipase, chymotrypsin (trypsin),
carboxypeptidase, nucleases
• Regulation of pancreatic secretions
– Secretin - stimulates release of pancreatic fluid
– cholecystokinin
15 - 13
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
The Pancreas
15 - 14
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
15 - 15
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 - 16
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
15 - 17
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
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
15 - 19
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 - 20
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
15 - 21
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Nutrition and Nutrients
A. 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.
15 - 22
Carbohydrates
• Sources
• Utilization
• requirements
15 - 23
Lipids
• Sources
• Utilization
• Requirements
15 - 24
proteins
• Sources
• requirements
15 - 25
vitamins
• Fat soluble
• Water soluble
15 - 26
minerals
• Characteristics
• Major minerals
• Trace elements
15 - 27