Unit 10 Chapter 35 The Digestive Endocrine Systems and
The Digestive System Functions: Ingestion Mechanical & chemical digestion Absorption Elimination of solid wastes
The Digestive System Mouth: Teeth Adapted for tearing & grinding food Tongue Adapted for tasting, & swallowing food, speech Salivary glands Secretes enzymes for digestion of starch
The Digestive System Esophagus Muscular passageway that connects the throat to the stomach Peristalsis Wavelike contractions for moving food through the digestive tract
The Digestive System Stomach Muscular, pouch-like enlargement of the digestive tract Mechanical digestion, muscular churning Chemical digestion, gastric fluids begin the digestion of protein
The Digestive System Small intestine Muscular tube connecting the stomach and large intestine Completion of digestion by chemicals added from pancreas & liver Absorption of food by villi Fingerlike projections that increase the surface area
Cross-section of Small Intestine showing villi
The Digestive System Liver (I) Gall bladder (H) Pancreas (D) Large organ that produces bile, which breaks down fats Gall bladder (H) Small organ storing bile from liver Pancreas (D) Soft gland that secretes both digestive enzymes & hormones
The Digestive System Large intestine Muscular tube leading from the small intestine to the rectum Absorption of water & minerals Synthesis of vitamins by symbiotic bacteria Elimination of indigestible wastes
Nutrition Carbohydrates (sugars & starches) The body’s main source for energy Lipids (fats, oils & waxes) Stores energy for the body and used as building materials for cell membrane Proteins Provides cell structure & function, i.e. enzymes, hormones, antibodies, etc
Nutrition Minerals & vitamins For normal growth and chemical reactions Minerals are inorganic, such as iron, iodine, & sodium Vitamins are organic, such as riboflavin, niacin, & ascorbic acid Water Facilitates chemical reactions, universal solvent, maintains body temperature
Calories measure energy content of food in units of heat
The Endocrine System Ductless glands that secrete hormones into the bloodstream Hormones Chemical messengers relaying information to other, target, organs
The Endocrine System Negative feedback Increasing one hormone inhibits another to reduce the production of the second hormone Ex: insulin decreases sugar while glucagon increases sugar, together maintaining blood sugar levels
The Endocrine System Hypothalamus Portion of the brain that connects the nervous and endocrine system (pituitary g.) Pituitary gland Secretes 9 hormones that directly regulate the actions of several other endocrine glands Ex: Growth hormone is essential for normal growth & development
The Endocrine System Thyroid gland Has a major role in regulating the body’s metabolism Ex: Calcitonin regulates calcium levels in the blood
The Endocrine System Adrenal gland Plays a major role in preparing the body for stressful situations Ex: Epinephrine (adrenalin) is associated with the body’s fight or flight reactions