The Digestive System Daniel Condo - PowerPoint Presentation

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The Digestive System

Daniel Condo

11

th

Grade Health

Functions of the Digestive System

Ingestion

Digestion

Movement/PropulsionAbsorptionElimination

Order of Digestion

Mouth

Pharynx

EsophagusStomachSmall IntestineLarge IntenstineRectum and Anus

Mouth

Functions:

Ingestion, Digestion, and Movement

-Ingestion: - Taking in food and chewing-Digestion: - Mechanical breakdown= Teeth (chewing)

- Chemical breakdown= Saliva (Enzymes)-Movement: -

Tongue pushes food to back of mouth - Swallowing Reflex starts in mouth, moving food into the Pharynx

Extra Credit Question

How many teeth are in your mouth?

Answer = 32

Pharynx

Commonly known as the Throat

Functions:

Movement-Movement: - Swallowing Reflex - Tongue blocks food from going back into mouth

- Nasal passage is blocked off - Larynx or Windpipe is blocked off

- Constrictor muscles move food to the esophagus

Esophagus

Function:

Movement

-Movement: - Upper Sphincter* opens allowing food in from the Pharynx, then closes - Peristalsis** moves the food down the Esophagus - Lower Sphincter opens to pass food into the Stomach, then closes *Sphincter = muscular opening

**Peristalsis = Involuntary , wave-like muscular movement

Stomach

Functions:

Digestion, Absorption, Movement-Digestion: - Mechanical breakdown occurs when involuntary muscles of stomach churn food with Gastric Juices (stomach acid) - Chemical breakdown occurs when gastric juices (including enzymes) separate food into smaller molecules

- Lower Sphincter of Esophagus closes when mixing to keep out gastric juices

Stomach cont.

-Absorption:

- Now broken down into smaller molecules some nutrients can be absorb by the stomach wall - Stomach wall (Rugae) unfolds allowing more surface area for absorption

-Movement: -Sphincter opens at base of the stomach to allow food (Chyme) into Small Intestine

- Peristalsis of stomach moves it into SI

Better Understanding of the Stomach

https://www.youtube.com/watch?v=URHBBE3RKEs

Small Intestine

Functions:

Digestion, Absorption, Movement-Digestion: - Chyme is exposed to more enzymes from ducts lining the SI - Majority of digestion is done in the Small Intestine; mainly chemically

- Nutrients are now broken down into easily absorbable compounds

Small Intestine cont.

-Absorption:

- SI is the longest section of the Digestive System to maximize absorption - Also takes the longest for food to travel to again maximize absorption - SI is lined with small finger-like folds called Villi which absorb nutrients while creating more surface area-Movement: - SI is lined with two layers of muscle that pass

chyme into the Large Intestine through peristalsis

Large Intestine

Functions:

Absorption, Movement

-Absorption: - Large Intestine absorbs water and electrolytes from remaining chyme - LI also forms remaining

chyme, which is mainly waste, into feces

- Movement:

- LI utilizing peristalsis to some extent - Main movement is cause by large muscular contractions 2-3 times a day

Rectum

Function:

Elimination

-Elimination: - Main function of the rectum is store feces until an appropriate time for excretion

Anus

Function:

Elimination

-Elimination: - Anus has 2 Sphincters - Internal sphincter opens involuntary and brings on the sensation of having to “go”

- The External sphincter is controlled voluntarily and allows to choose when you “go”

What you need to knowFunctions of Digestive System

Order of Digestion

Main job of each organ