Unit 10Chapter 35The 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)

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