The Digestive System

THE DIGESTIVE SYSTEMChapter 38

DIGESTIVE SYSTEM Breaks food down into a form usable by

cells (small enough to diffuse into cells).

NUTRIENTS Water Carbohydrates Fats Proteins Vitamins Minerals

THE DIGESTIVE ENZYMES

Site Mouth

Stomach

Small intestine(from pancreas)

Small intestine

Enzyme Role in Digestion

Section 38-2

Salivary amylase

Pepsin

Amylase

Trypsin

Lipase

Maltase, sucrase, lactase

Peptidase

Breaks down starches into disaccharidesBreaks down proteins into large peptidesContinues the breakdown of starch

Continues the breakdown of proteinBreaks down fat

Breaks down remaining disaccharides into monosaccharidesBreaks down dipeptides into amino acids.

PATHWAY Mouth Esophagus Stomach Small intestine Large intestine Rectum Anus

Mouth

Salivary glands

StomachPancreas (behind stomach)Large intestine

Small intestine

Rectum

Gallbladder (behind liver)

Liver

Esophagus

Pharynx

THE DIGESTIVE SYSTEMSection 38-2

ACCESSORY GLANDS Salivary glands Liver Pancreas

Liver

Gallbladder

Duodenum

Bile duct

Pancreas

Pancreatic duct

To rest of small intestine

THE LIVER AND THE PANCREASSection 38-2

ABSORPTION Small intestine nutrients Large intestine water

Small Intestine Villus

Circular folds

Villi

Epithelial cells

Capillaries

Lacteal

VeinArtery

THE SMALL INTESTINESection 38-2

DIGESTIVE DISORDERS Heartburn Ulcers Diarrhea Constipation

THE EXCRETORY SYSTEMChapter 38

FUNCTIONS Helps maintain homeostasis. Rids the body of the wastes of

metabolism. Excess salts Carbon dioxide Urea Excess water

Maintains blood volume and pH.

ORGANS OF EXCRETION Liver Lungs Kidneys Skin

LIVER Blood from the intestines flows through

the liver to be detoxified before traveling to the rest of the body.

Breaks down excess proteins into the waste product urea.

LUNGS Excrete carbon dioxide, water and heat.

KIDNEYS

Remove waste products from the blood. Excess water, excess salts and urea which

make up urine. Maintain blood pH. Regulate water content of blood

(volume).

Kidney (Cross Section)

Cortex

Medulla

Vein Artery

Kidney

Ureter

Urinary bladder

Urethra

THE URINARY SYSTEMSection 38-3

KIDNEY FUNCTION Filtration – everything but cells are

filtered out of the blood (passive). Reabsorption – water and nutrients

are absorbed back into the blood (active). What remains behind is urine. Excess water Salts Urea

Kidney Nephron

Cortex

Medulla Renal artery

Renal vein

Ureter

To the bladder

Bowman’s capsule

Glomerulus

Capillaries

Collecting duct

To the ureterLoop of Henle

Artery

Vein

STRUCTURE OF THE KIDNEYSSection 38-3

KIDNEY FAILURE

Having two kidneys provides a backup. If both fail, a transplant or dialysis is

needed.

Vein

Artery

Shunt

Air detector Dialysis machine

Blood pump

Blood in tubing flows through dialysis fluid

Used dialysis fluid

Compressed air

Fresh dialysis

fluid

KIDNEY DIALYSISSection 38-3

SKIN Excretes sweat: water, salt and urea. Excretes heat – helps maintain

homeostasis.