THE HUMAN DIGESTIVE SYSTEM The Human Digestive System

THE HUMAN DIGESTIVE SYSTEM

The Human Digestive System We will divide the Human Digestive System into two main topics: 1. Nutrition and what our body needs 2. How the human body breaks down food and makes it available for use by ALL CELLS.

How do living things get energy? 1. 2. 3. 4. 5. They get their energy from food or photosynthesis After food is broken down in the body, it can be used in respiration to produce energy The slow burning of food in your body is called oxidation Some energy is given off as heat. The waste products are carbon dioxide and water.

Calories The amount of energy required to raise one gram of water by one degree Celsius. You don’t have to copy this down but, 1000 (Scientific) Calories equals 1 Food Calorie.

Different foods give off different amounts of energy. Fat Protein Carbohydrate s Ø Ø Ø 9 calories of energy/gram 4 calories of energy/gram • Boys your age need about 2800 calories/day • Girls your age need about 2400 calories/day

Nutrition Require Nutrients which are foundfood in Nutrients are needed energy, growth, and all for other life processes There are 6 kinds of nutrients: q q q Carbohydrates Fats Proteins Vitamins Minerals Water

Carbohydrates are your main source of energy There are three kinds of carbohydrates: � Simple (Sugars) � Complex (Starches) � Fiber

Types of Carbohydrates Sugar (Simple) Sugar like candy Used quickly by your body Gives your body short, quick bursts of energy Starch (Complex) Starches like bread and pasta Gives your body energy over long periods of time. Fiber Helps move food through your digestive system (and prevent

Fats are found in: � Steak, Ice Cream, Peanuts, Bacon, Oil, Lard, etc… These are energy storage nutrients. The stored energy in fats is used if energy from carbohydrates is used up. Fats are used for insulation: to keep you warm Fats are used to protect/cushion your organs. 2 Types: � Saturated Fats

Protein Proteins are the building blocks of living material. You get protein from: � Milk, fish, cheese, peanuts, eggs, and meat. Proteins are used for: 1. 2. 3. 4. Energy Growth and Repair (building tissues and muscles) Making Enzymes: substances that regulate/control chemical activity. Hormones: the chemical messengers of the

Protein continued… The building blocks of proteins are Amino Acids. � Proteins are formed when smaller amino acid molecules join together. There about twenty (20) amino acids. � Twelve (12) are made in the body. � Eight (8) must be taken into the body

Minerals are inorganic nutrients that help regulate chemical reactions and are needed by the body to develop properly Each Mineral has a different job: Iron Forms red blood cells, which carry oxygen throughout the Calcium body Build strong teeth and bones Zinc Aids in protein formation Iodine Controls body growth and oxidation of food

What happens when you don’t get enough Iodine?

A condition called Goiter!

Vitamins Nutrients that are needed in small amounts (micronutrients) for growth , regulation of body functions, and prevention of diseases You get most of the vitamins you need from food. Exception: Vitamins D and K are made in your body If you don’t get vitamins you from get a Vitamin B 2 enough Helps release energy deficiency nutrientsand repair of body tissue. Growth Vitamin Lack of Vit. C leads to scurvy C Enhances night vision, and Vitamin maintains skin and bones. A

Water All the chemical reactions in the body take place in water. Water carries nutrients to and from the organs It helps your body maintain its temperature You get water from the foods you eat and the fluids you drink. Your body is about 50%-60% water.

The Ever Evolving Food Pyramid

How do we break down food? Mechanical Digestion Chemical Digestion Breakdown food physically, using pressure to break apart larger chunks. Example: Breaking down food using water, enzymes, acids, etc… Example: You body uses mechanical digestion to increase the surface area of food, which speeds up chemical digestion.

How do we move food? Using muscles we can control �Chewing and Swallowing Using muscles out of our control �Stomach Churning �Peristalsis: A wavelike muscle contraction to squeeze food through a tube. http: //www. westga. edu/~lkral/peristalsis/index. html http: //www. innerbody. com/anim/mouth. html

The Digestive Pathway Mouth (Food) Throat / Pharynx (Bolus ) Mechanical Dig Teeth Chemical Dig Salivary Glands Saliva with Ptyalin A tube to transport food water and air

The Digestive Pathway Mouth (Food) Throat / Pharynx (Bolus )

The Digestive Pathway Epiglottis (Bolus ) Directs: Lungs �Air to (Respiratory ______ System) Stomach (Digestive System) �Water to ______ Stomach (Digestive System) �Food to ______

The Digestive Pathway Epiglottis (Bolus ) Source – centerforsoundsleep Source – mycotopia

The Digestive Pathway Esophogu s (Bolus ) Moves the bolus using Peristalsis Source – centerforsoundsleep Source – mycotopia

The Digestive Pathway The Stomach (Bolus) Mechanical Dig Churning Chemical Dig HCl to digest Carbs. (Hydrochloric Acid) Pepsin to digest Proteins (Enzyme)

The Digestive Pathway Small Intestines (Chyme) First section: The duodenum Moves food using Peristalsis Increases surface area with villi Digestion of Fats begin here Chemically breaks down food using secretions from the: Pancreas Liver

The Digestive Pathway Small Intestines & The Accessory Organs The Pancreas and Liver Pancrea s Secretes Pancreatic juices to breakdown nutrients Liver Creates Bile: • Breaks down Fats • Stored in Gall Bladder

The Digestive Pathway Small Intestines Second Section Now that your food is FULLY BROKEN DOWN (digested) Nutrients are absorbed by the villi What increases the rate/amount of absorption? � The villi’s shape increase the surface area � The intestines are looonng. (Chyme) The chyme is pushed through by peristalsis.

The Digestive Pathway Large Intestines Now that your food is FULLY ABSORBED Reabsorbes: � Water � Vitamin (Feces) B&K

The Digestive Pathway Rectum Feces is stored here Anus Feces is expelled here

Tongue Salivary Gland Esophag Epiglottis us Liver Gall Bladder Stomach Pancreas Bile Duodenu Duct m Small Intestines Villi Large Rectum. Intestines Appendix Anus

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