Stomach & SI 2016.notebook

1

May 11, 2016

May 6­2:26 PM

Joe's Stomach

May 6­2:26 PM

Stomach­ flexible bag that holds food & breaks it down to liquid form

­ GASTRIC JUICES

­ HCl ­ released by the parietal cells; aids in activation of pepsinogen to pepsin, kills any harmful substances

­ Mucous ­ protection from itself

­ Pepsinogen ­ an inactive enzyme, which digests proteins. It is released by the chief cells and it is converted to pepsin upon mixing with HCl.

­ peristalsis of the stomach grinds, squeezes & churns food

This mixes with the secretions of the stomach to form CHYME

Stomach & SI 2016.notebook

2

May 11, 2016

May 6­7:55 PM

Chyme leaves the stomach through the pyloric sphincter. It enters the 1st part of the small intestine (duodenum) and is mixed with

1. enzymes from the pancreas, ex. lipase, trypsin, lactase

2. bile from the gall bladder (made in the liver) to emulsify fat

3. bicarbonate to neutralize stomach acid

mechanical

chemical

May 6­2:26 PM

The small intestine is divided into 3 sections;

duodenum

jejunum

ileum

Food is moved by peristaltic contractions.

The surface area of absorption must be

large, therefore, the intestines are long

and have projections on the wall. These projections

are called villi and they are also covered with tiny, bumps called microvilli.

Stomach & SI 2016.notebook

3

May 11, 2016

May 8­8:35 AM

AbsorptionNutrients move from the digestive tract into the blood stream as chyme passes through the _______________. The surface area is immensely large due to:

• length of SI

• villi

• microvilli

Stomach & SI 2016.notebook

4

May 11, 2016

May 6­2:26 PM

Homework

The Digestive System Handout

Joe's Intestine

Absorption of Materials Handout.