Digestion Unit Flashcards

5 steps of digestion

Ingestion, Movement of Food, Digestion, Absorption, Defecation

Ingestion

Taking food into the body (eating)

Movement of Food

Passage of food along the gastrointestinal tract (GI tract)

Digestion

The breakdown of food by chemical and mechanical processes

2 types of Digestion

Chemical Digestion, Mechanical Digestion

Chemical Digestion

Involves chemical reactions that break food down into smaller and smaller molecules that are usable by body cells

Mechanical Digestion

Movement of the food within and through the digestive tract that help break the food apart physically.

Absorption

Passage of food molecules from the GI tract into the bloodstream to be delivered to cells

Defecation

Removing non-digested food from the body.

A continues tube running through the body cavity and extending from the mouth to the anus.

Gastrointestinal Tract (GI tract)

Organs that food does not physically pass through, but that play a important role in digestion.

Accessory Organs

The largest serous membrane in the body. This tissue lines certain internal cavities, forming a smooth, transparent, two-layered membrane lubricated by a fluid derived from serum.

Peritoneum

3 types of peritoneum thingies

Parietal peritoneum, Visceral peritoneum, Peritoneal cavity

Serous membranes in the body

Peritoneum, Pericardium, and Pleura

Parietal Peritoneum

lines the wall of the body cavity

Visceral Peritoneum

Membrane that covers and binds organs

Peritoneal Cavity

The space between the membranes that contains fluid (peritoneal fluid)

Mouth

Formed by the cheeks, hard and soft palates, lips, and tongue

Tongue

Composed of skeletal muscle tissue covered with a mucous membrane. Aids in swallowing and speech. The tongue is covered in small projections called papillae.

Papillae function

Many papillae contain the taste buds, and the rough surface of the tongue helps with movement of food.

How can we taste?

Food must be dissolved in saliva for us to taste.

Salivary Glands

Major portion of saliva is produced by these glands (Which are located behind the mouth) and is poured into ducts that open into the mouth.

Buccal Glands

Some saliva comes from here. These are located in the membranes of the mouth and keep the mouth moist.

Three pairs of salivary glands

Parotid, Submandibular, and sublingual

What is mumps?

Mumps is an infection of the parotid gland

What is saliva (in humans) made of?

99.5% water, plus electrolytes, mucus, white blood cells, enzymes, and antimicrobial agnets.

What does saliva do?

It is responsible for lubricating and dissolving food. Contains first digestive enzymes which begins the chemical breakdown of food.

Salivary Amylaze

Begins the breakdown of carbohydrates into simpler sugars

What food is called after the teeth, tongue, and saliva work on it.

Bolus

A collapsible, muscular tube lined with mucus that lies behind the trachea

Esophagus

Wavelike, muscular contractions along the GI tract

Peristalsis

What does the upper esophageal sphincter and the lower esophageal sphincter do?

The upper prevents air from entering the esophagus during breathing. The lower opens up and allows food into the stomach, preventing heartburn.

What is heartburn?

Heartburn is when the lower esophageal sphincter does not close properly, and allows stomach contents to enter the esophagus.

What does the epiglottis do?

When swallowing, it covers the trachea to prevent food/liquid from going into the trachea.

Uvula?

Flips up and covers the nasal passage (nasopharynx) to prevent food/liquid going up the nose.

What process does the stomach use to break down food?

Both chemical and mechanical (physical) processes.

What chemical helps digestion in the stomach?

Pepsin, which is activated by hydrochloric acid.

Why doesn’t the stomach self destruct?

Because of a mucus lining on the stomach which prevents acids and enzymes from harming it.

What is an ulcer?

An open sore in the lining of the stomach.

Under what circumstances can absorption occur in the stomach?

Usually, never. But if your severly deydrated, or if you’ve drunk certain drugs or alcohol, it can get absorbed into your bloodstream through the stomach lining.

After the bolus has went through the stomach, what is it now called?

Chyme

What organ creates insulin

The pancreas. And insulin is an endocrine gland which aids in regulating blood sugar.

What enzymes are in pancreatic juices, and what do they act upon?

Bicarbonate- Neutralizes hydrochloric acid

Pancreatic Amylase- Helps break down carbohydrates

Trypsin- Breaks down proteins

Lipase- Breaks down lipids (fats)

Where does pancreatic juice enter the GI tract?

It enters through two ducts that enter the duodenum.

About how many functions does the liver have, and what is the main one?

The liver has over 500 functions. The function we talk about the most in relation to digestion is that it makes bile. (although its main function is to filter blood coming from the digestive tract)

What organ stores bile?

The gallblader

Bile

Enzyme that comes from broken down red blood cells. It helps break apart fats through a mechanical process.

What are the three areas of the small intestine?

Duodenum, jejunum, ileum

Small intestine

Makes some of its own enzymes and gets some from the pancreas. Most all digestion of nutrients and their absorption into the blood stream occurs here. Final digestion takes place here.

Why are villi on the small intestine important?

Villi increase the small intestines surface area, and absorption occurs through the villi.

What is the junction between the small and large intestines?

The cecum/appendix

What are the 5 steps of the large intestine?

Ascending colon, Tranverse colon, Descending colon, Sigmoid Colon, Rectum

What is the main function of the large intestine?

The large intestine reabsorbs water back into the bloodstream and stores waste until ready to be removed.

What do E. coli bacteria do?

E. coli bacteria feed off undigested food remains and give vitamins that the body absorbs. The smell of poop comes from E. coli bacteria

18 steps of digestion

Mouth, pharynx, epiglottis, upper esophageal sphincter, esophagus, lower esophageal sphincter, stomach, pyloric sphincter, duodenum, jujenum, ileum, cecum/appendix, ascending colon, tranverse colon, descending colon, sigmoid colon, rectum anus.

Jaundice

Yellow coloration of the eyes, skin and mucous membranes; occur due to the buildup of bilirubin. Can be caused by a variety of liver dysfunctions

Hepatitis

Inflimmation of the liver. infectious agents include certain drugs and toxic agents

Appendicitis

Inflimmation of the appendix

Gallstone

Caused by the crystallization of cholesterol in the bile.

Cirrhosis

A scarred liver that results from long term infection. Can be caused by hepatitis, toxic chemicals or alcoholism