Digestive and Circulatory Systems

9. a. Students know how the complementary activity of major body systems provides cells with oxygen and nutrients and removes toxic waste products such as carbon dioxide.

&9. f.* Students know the individual functions and sites of

secretion of digestive enzymes (amylases, proteases, nucleases, lipases), stomach acid, and bile salts.

Oxygen molecules move from the air to the alveoli of the lungs and then to the circulatory system

Circulatory System From the circulatory

system glucose and oxygen molecules move from the capillaries into the cells of the body where cellular respiration occurs.

The Heart The heart is made up

mostly of cardiac muscle tissue, which contracts to pump blood.

O2 and CO2 in the Blood The gas exchange

process is reversed for the removal of carbon dioxide from its higher concentration in the cells to the circulatory system and, finally, to its elimination by exhalation from the lungs.

The Digestive System The digestive system

delivers nutrients (e.g., glucose) to the circulatory system.

Source of Energy All of our energy

comes from the macromolecules in the food we eat. Carbohydrates Lipids Proteins Nucleic Acids

Digestive Enzymes Food proceeds from

the mouth through the stomach and through the small intestines).

Salivary glands secrete amylase enzymes that change starch into sugar.

Digestive System in the Human Body

Stomach acid and gastric enzymes begin the breakdown of protein

Pancreas Secretes amylase

enzymes that change starch into sugar.

Secretes lipase enzymes to break down fat molecules (which contain 3 fatty acids) to free fatty acids plus diglycerides (which contain 2 fatty acids) and monoglycerides (which contain 1 fatty acid).

Liver Bile secreted by the liver

furthers the process of digestion, emulsifying fats and facilitating digestion of lipids.

The liver removes toxic materials from the blood, stores them, and excretes them into the bile. The liver also regulates blood glucose.

The concentration of sugar in the blood is monitored, and sugar can be stored or pulled from reserves (glycogen) in the liver and muscles

Cross Section of the Small Intestine

Villi in the Small Intestine

•Digest carbohydrates, fats, proteins and nutrients

Large Intestine Absorbs water and

ions

Carbohydrate

DigestionProtein

DigestionNucleic Acid

DigestionFat

Digestion

Mo

ut

h Salivary Amylase(starches into sugars)

Stom

ach

Pepsin

(proteins into small

polypeptides)

Sm

all

Intestin

e

Pancreatic Amylase

(starches into sugars)

Pancreatic Pancreatic nucleases

Bile Salts

Pancreatic Lipase

Larg

e

Intestin

e

Draw a concept map of the enzymes involved in digestion

In case……… Amino acids contained in proteins can also

serve as an energy source, but first the amino acids must be deaminated, or chemically converted, in the liver, producing ammonia (a toxic product), which is converted to water-soluble urea and excreted by the kidneys.

Kidneys The water, urea, and

salts that remain in the nephron are eliminated as urine.

Kidneys Microscopic nephrons within the kidney filter out

body wastes, regulate water, and stabilize electrolyte levels in blood.

The End