New Unit-HUMAN PHYSIOLOGY  We’ll be covering the life functions of -  Nutrition  Circulation (Transport)  Respiration  Excretion  Coordination ( Nervous and Endocrine systems)  Locomotion (Skeletal/ Muscular systems)

HOMEOSTASIS  Is necessary for all life  Homeostasis is more easily maintained by multicellular organisms with “division of labor” in their organ systems.

First Life Function:NUTRITION  Six basic kinds of nutrients can be found in food-  Carbohydrates, fats, proteins, minerals, vitamins, and water  These are essential to proper body function.

We’ll begin with CARBOHYDRATES  Found in bread, fruits, vegetables, pasta, rice, cereal. Fiber, such as bran and pears, essential for good digestion.  Used for energy  Made of monosaccharides (glucose)

DIGESTION of carbohydrates  Begins in mouth-teeth make smaller particles for more surface area.  Salivary amylase begins chemical digestion.  Digestion is finished in small intestine, where products are absorbed

ENZYMES for carbohydrate digestion  Salivary amylase from salivary glands in mouth.  Maltase, Sucrase, Lactase from small intestine.  Pancreatic amylase from pancreas

LIPIDS (Fats, Oils)  Found in meats, nuts, dairy products, cooking oils, butter.  Used for energy and building materials (cell membrane)  Made of glycerol and fatty acids

DIGESTION of lipids  Begins and ends in Small intestine  Small intestine contains structures called villi to increase the surface area for absorption

ENZYME for digestion of lipids  Pancreatic lipase from pancreas

PROTEINS  Found in meats, fish, eggs, dairy, beans, whole grains  Used for enzymes, antibodies, hormones, muscles, plasma membrane  Made of amino acids

DIGESTION of proteins  Begins in stomach  Finished in small intestine

ENZYMES for digestion of proteins  Pepsin in stomach  Peptidase in small intestine

“Accessory” organs (not in the alimentary canal)  Salivary glands and pancreas produce enzymes to help digestion of food  Liver produces bile that “emulsifies” fat, making it into smaller bubbles for more surface area.  Galls bladder stores bile

Other important organs  Large intestine absorbs water and stores wastes before egestion. Some “friendly” bacteria help make some vitamins

AND  The mouth breaks food into smaller particles for more surface area. This is mechanical digestion, not a chemical change  The esophagus pushes food into the digestive tract, beginning peristalsis, rhythmic contractions that churn the food and move it on.

Chemical Reaction  The chemical reaction that is used in digestion is called HYDROLYSIS  This is a reaction where water splits the molecule into smaller parts: Ex-Protein into polypeptides into dipeptides into amino acids

ENZYMES  What are they?  A protein (coded for by DNA) that changes the rate of a reaction.  Some of these reactions would be so slow that it would seem that they wouldn’t occur at all.  What affects enzyme action?  Temperature  pH  Amounts of “substrate”(the chemical it works on) and the amount of enzyme

ENZYME ACTION  There is an “optimum” temperature, and an optimum (or “best) pH for each enzyme action, depending on where it is working.  Example-Enzymes that work in the mouth would no longer work in the stomach. The pH changes dramatically. The enzyme is denatured, losing its shape.

ENZYME ACTION  The amount of substrate, the substance the enzyme works on, affects the rate of the reaction.  The amount of enzyme affects the reaction.  BUT, an enzyme can only work so fast, so the rate will level out.

Enzyme Action- What might the optimum pH be for each enzyme?

Enzymes are specific  An enzyme only works in a reaction with one molecule- lactase hydrolyzes lactose or assembles lactose.

Take your vitamins!  Vitamins are organic molecules that are required in small amounts to maintain growth and metabolism.  They are called co- enzymes because they help enzymes function.

Minerals aren’t just for miners !  Minerals are inorganic substances that serve as building blocks – bones- or take part in chemical reactions.

DISORDERS of digestive system  Diarrhea can be caused by infection or poor diet  Constipation is caused by lack of fiber and/or water in your diet  These can both be relieved by diet and/or medication