Nutrition & Digestion

Digestion

Interpret the different functions of the digestive system organs.

Outline the pathway food follows through the digestive tract.

Identify the role of enzymes in chemical digestion.

Section Objectives:

The main function of the digestive system is to disassemble the food you eat into its component molecules so that it can be used as energy for your body.

Digestion is accomplished through a number of steps.

Functions of the Digestive SystemFunctions of the Digestive System

Digestion

chemical process by which food is broken down into smaller molecules used by the body.

Digestion

Involves 3 activities:

A. Mechanical digestion (chewing)

B. Chemical digestionC. Absorption

Structures of the digestive tract and their functions.

1. Mouth – chewing

1st place digestion begins.

Saliva which contains a digestive enzyme, called amylase starts the process.

Digestion begins

3 Structures of Mouth

A. Tongue - tastes 4 distinct tastes (bitter, salty, sour, sweet)

B. Salivary glands - secrete saliva, start of digestive process.

C. Teeth

Incisors

Gums

Soft palate

Tonsils

Opening of salivary gland duct

Cuspids or canines

Bicuspids or premolars

Molars TongueTeeth

Uvula

Hard palate

Your Mouth

3 Types of teeth

1. Incisors - biting / tearing foods

2. Canines - tear / shred food

3. Molars - grind

For those who like a nice dip look at the above oral cancers of the mouth and tongue!!

2. Pharynx

area in back of the throat that connects the nose and the mouth to the digestive and respiratory tract.

3. Esophagus

tube that carries food to the stomach.

Epiglottis - a small flap of tissue that seals off the trachea during the swallowing of food.

4. Stomach

pouch like structure with thick expandable muscular walls.

•Hydrochloric acid increases the acidity of the stomach contents to pH2.

Ulcer Causing Bacteria

Polyps in the stomach

Heartburn

Stomach

A. Contains HCl, the enzyme pepsin for digestion of proteins. Both are produced by the glands of the stomach for breaking down food.

Stomach

B. Growling of the stomach is the contractions of the stomach as it mixes the food, etc.

When there is less food the noise is louder.

Stomach

C. Mucus - coats the stomach wall for protection and helps to lubricate and ease movement of food.

Ulcers

5. Small intestine A tube about 7 m

long that digests carbohydrates, fats completes digestion of proteins and absorbs digested nutrients. 2.5 cm in diameter.

Polyp in small intestine

3 parts of small intestine

Small Intestines

A. Villi - fingerlike projections in the small intestine that help increase the surface area for absorption.

5. Small Intestines cont.

Folds of the small intestine

B. Bile - a salt containing a detergent that is secreted into the small intestine by the gall bladder.

Bile helps to break up fats.

5. Small Intestines

fingerlike structure found near the junction in the small and large intestine.

Appendicitis - when appendix becomes inflamed. Treatment is the removal of the appendix.

Appendix

Appendix annimation

Appendics

Large Intestines

6. Large Intestine

A large tube in diameter about 1.5 m long that absorbs water from the material remaining in the digestive tract.

Colon Cancer

Large Intestine

A. Peristalsis - wavelike movement that moves materials.

Other places that this movement occurs is in the esophagus and small intestines.

Premalignant polyps colon

Large Intestine

B. Feces - undigested solid waste material emitted.

Large Intestine

C. Bacteria - found in the large intestine, aids in digestion.

Takes 12-24 hours for food to move from mouth to anus.

Sigmoid Colon

Hiatal Colon Reflex

secretes pancreatic fluid into the small intestine.

Helps digest fats, proteins, and carbohydrates. Pancreatic fluid is a mixture of enzymes and sodium bicarbonate.

Insulin controls the uptake of glucose by the cells.

7. Pancreas

8. Liver Largest internal organ,

serves as the body’s primary storage place main chemical factory and detoxification site.

Gets blood from intestines before the blood goes to the rest of the body.

Cross-section of a normal liver. The holes are bile ducts.

2 lobes of the liver

Liver Hepatitis - infection of the liver by a virus. Can be sexually transmitted, by blood products, or feces.

Hepatic Cell Carcinoma

LiverCirrhosis - scarring of

the liver, can be caused from Hepatitis or alcoholism.

Results can be death. Cirrhosis

9. Gall Bladder stores bile made

by the liver. Takes water from solution making bile more concentrated. Bile then is released into small intestine as needed.

stone that stuck into the cystic duct

Gall stones

Gall Bladder cont.

Calcified Stones taken out from surgically removed gallbladder.

AnswerMouth

Salivary Glands

Esophagus

Pharynx

Oral Cavity

Pancreas

Gall BladderStomach

Liver

Large Intestine

RectumAnus

Small Intestine

Eating the American Way

Nutrition

Recognize the contribution of the six classes of nutrients to body nutrition.

Identify the role of the liver in food storage.

Relate caloric intake to weight loss or gain.

Section Objectives:

Six basic kinds of nutrients can be found in foods: carbohydrates, fats, proteins, minerals, vitamins, and water.

You supply your body with these nutrients when you eat foods from the five main food groups.

The Vital Nutrients

Nutrients

Substances needed for:Cell repair/MaintenceCell growthEnergy

Obtained from the food we eat

Diet -Digestive

6 Main Nutrients

A. CarbohydratesB. Fats/LipidsC. ProteinsD. VitaminsE. MineralsF. Water

A. 3 Carbohydrates

1. Sugars1. Sugars

A. Glucose - sugar cells obtain most of their energy from C6H12O6.

B. Glycogen - made up of thousands of glucose units.

(Body stores glycogen in the liver and muscles, if an excess then stored as fat.)

2. Starches

made of many sugars. Aka complex carbs.

Ex: Breads, pasta and potatoes.

3. Cellulose/Fiber

contained in cell walls of plants. Fiber that aids in digestion. May help provide some protection against heart disease and some types of cancer.

B. Fats - Lipids

store other nutrients and are a source of stored energy.

Made of three fatty acids joined by glycerol molecule.

Use lipids to make cell membranes, hormones, oils in hair and skin.

Two types - Saturated and Unsaturated fats.

(Unsaturated fat is considered the healthier of the two, because it is liquid at room temperature.)

C. Proteins

the construction materials for the body parts such as muscle, skin and blood.

1. Amino Acids - make up proteins.

There are 20 Amino Acids

Note: Essential amino acids can not be made by the body, there are eight of these. A proper diet would provide these for the body. Foods such as meats, eggs and dairy products contain them.

Fluorine (F) Calcium (Ca)

Iodine (I)

Iron (Fe)

Sodium (Na)

Magnesium (Mg)

Sulfur (S)

Potassium (K)

Copper (Cu)

Phosphorus (P)

Minerals and vitamins

D. Vitamins

complex organic molecules that are needed by the body in very small amounts.

Two types: 1. Water soluble - dissolve in

water. Cannot be stored in the body, so must have regularly. Ex: B1(Thiamin), B2 (Riboflavin), Niacin, B6, B12, C.

2. Fat Soluble - stored in fat or liver for future use by the body. Ex: Vit. A, D, E, K

This table lists foods that contain fat-soluble and water-soluble vitamins.

VitaminsFat-soluble

Function Source

A Maintain health of epithelial cells; formation of light absorbing pigment; growth of bones and teeth

D Absorption of calcium and phosphorus in digestive tract

E Formation of DNA, RNA, and red blood cells

K Blood clotting

Liver, broccoli, green and yellow vegetables, tomatoes, butter, egg yolk

Egg yolk, shrimp, yeast, liver, fortified milk; produced in the skin upon exposure to ultraviolet rays in sunlightLeafy vegetables, milk, butterGreen vegetables, tomatoes, produced by intestinal bacteria

VitaminsWater-soluble

Function Source

B1Sugar metabolism; synthesis of neurotransmitters

B2 (riboflavin) Sugar and protein metabolism in cells of eyes, skin, intestines, blood

Niacin Energy-releasing reactions; fat metabolism

B6 Fat metabolism

Ham, eggs, green vegetables, chicken, raisins, seafood, soybeans, milk Green vegetables, meats, yeast, eggs

Yeast, meats, liver, fish, whole-grain cereals, nutsSalmon, yeast, tomatoes, corn, spinach, liver, yogurt, wheat bran, whole-grain cereals and bread

Minerals and vitamins

VitaminsWater-soluble

Function Source

B12Red blood cell formation; metabolism of amino acids

Pantothenic acid Aerobic respiration; synthesis of hormones

Folic acid Synthesis of DNA and RNA; production of red and white blood cells

Biotin Aerobic respiration; fat metabolism

Liver, milk, cheese, eggs, meats

Milk, liver, yeast, green vegetables, whole-grain cereals and breadsLiver, leafy green vegetables, nuts, orange juiceYeast, liver, egg yolk

C Protein metabolism; wound healing

Citrus fruits, tomatoes, leafy green vegetables, broccoli, potatoes, peppers

Minerals and vitamins

E. Minerals

inorganic substances that perform vital functions in the body.

Calcium - found in dairy products . Necessary for strong bones and teeth, muscle and nerve activity and blood clotting.

Potassium , Sodium , and Magnesium - Necessary for nerve and muscle activity.

F. Water

necessary for life. Lose 3-5 liter of water a day through sweat , urine, etc.

About 67% of your body mass is water.

90% of the plasma is water.

F. Water

3 Functions: 1. To transport

nutrients and wastes 2. Cool body 3. Necessary for

chemical reactions.

Nutrition

Metabolism

sum of all the chemical processes that take place within an organism.

Energy

ability to do work.

Calorie

amount of heat energy needed to raise the temperature of 1 gram of water by 1oC. Measurement for energy.

The energy content of food is measured in units of heat called Calories, each of which represents a kilocalorie, or 1000 calories.

Some foods, especially those with fats, contain more Calories than others.

Calories and Metabolism

Metabolic Rate

Basal Metabolic Rate (BMR) - rate of metabolism at rest. BMR is equal to the numbers of kilocalories an animal uses in a set amount of time to maintain homeostasis.

Calculate your BMI -

Diseases and Conditions

4 Diseases from poor nutrition

1. Scurvy - caused from a lack of Vit. C

disease sailor once got because of the long voyage and poor diet.

Scurvy - vitamin C deficiency.

The effects of scurvy

4 Diseases from poor nutrition cont.

2. Night Blindness - caused from lack of Vit. A

3. Beriberi - Lack of B1. Most common in Asia where diet is mainly rice.

4. Rickets - caused from lack of Vit. D.

Rickets

2 Eating Disorders 1. Bulimia - consume

lots of food, but then binge. Possible problems, swollen salivary glands, kidney, liver and pancreas problems, tooth decay from stomach acid.

2. Anorexia - over exercise, but does not eat. Starvation occurs.

Digestion and the Human body

Endocrine System

Endocrine glands

series of ductless glands that release chemicals (hormones ) directly into the blood stream.

Hormones

Chemicals released in one part of an organism that affects another part. (Chemical messengers)

Two groups of hormones based on how they act on theirtarget cells.

A. Amino acid hormones - amino acids make proteins.

B. Steroid hormones - made from lipids . Can alter genetic activity of some cells.

Hypothalamus -

portion of the brain that controls the pituitary gland.

Indirectly controls growth, development and activities of the reproductive system.

Negative feedback system -self regulating

system of the endocrine system. As the hormone increases level in the blood production of the hormone at the gland decreases. (equilibrium)

Oxytocin -

for uterus contraction during birth. (stored in the posterior pituitary gland)

Pituitary gland -master endocrine gland -

growth hormone produced here. Indirectly controls growth, development and activities of the reproductive system.

Controls many other glands.

Endocrine System

hGH - human growth hormone -

stimulates division and growth of bone, muscle, and other body cells. Stimulates liver cells to release glucose (for energy) into blood during times of growth.

Robert Pershing Wadlow - Giant

Robert Pershing Wadlow was born on Feb. 22, 1918 in Alton, Illinois. At the time of his death at age 22, he was 8' 11.1" tall & 490 pounds, which made him the tallest person in history according to the Guinness Book of Records.

His parents, Addie and Harold Wadlow, always loved & protected him to the best of their abilities, honoring his desire to be treated as a "normal" person. They even destroyed his personal belongings after his death so that no one could profit from the exploitation of them.Robert promoted the International Shoe Company, which provided his size 37 shoes to him for free. Traveling for the shoe company, he visited over 800 towns and 41 states.

Robert's size was attributed to an overactive pituitary gland, which produced much higher than normal levels of growth hormone. Because of the extremely long legs caused by pituitary giantism, he had little sensation in his feet and did not feel any chafing until blisters formed. While making an appearance in 1940, a fatal infection set in when such a blister formed due to the braces he had to wear to strengthen his overly long legs. On the 15th of July, Robert Wadlow passed away in his sleep from the infection.

TSH - thyroid stimulating hormone -

stimulates development and activity of thyroid gland.

FSH - follicle stimulating hormone -

stimulates gonads to produce egg and sperm. Triggers puberty.

LH - Luteinizing hormone -

stimulates gonads to produce sex hormones. Triggers puberty.

Thyroid Gland -

makes a hormone that speeds up metabolism, growth and development. If thyroid malfunctions, may feel tired . May also gain weight.

Goiter -Growth caused by a

malfunction of the thyroid gland.

Adrenal gland -

located on top of the kidneys. Release hormones that prepare your body for stressful situations.

Epinephrine (ep uh NEF run )

often called adrenaline.

Norepinephrine

These hormones used during the fight or flight response.

Parathyroid gland -

produces Parathyroid hormone - increases the rate of calcium , phosphate, and magnesium absorption in the intestines, etc.

Ovary -

secretes female sex hormones (steroid)

Ovary releasing ovum

Estrogen -

Primary female hormone maintains female reproductive cycle .

Progesterone -

female hormone. Prepares and maintains uterus during pregnancy.

Testis -

secretes male sex hormones (steroid)

Testosterone -

Primary male hormone maintains reproductive cycle.

Pancreas -helps regulate the

sugar levels in body.

Insulin -

hormone that stimulates cells to take up sugar from the blood. (part of digestive and endocrine system)

Glycogen -

produced by alpha cells in the islets of Langerhans. Helps provide body with energy.

Diabetes -

disorder of pancreas. Some symptoms are excess sugar in blood, intense thirst, weakness and excessive urination.