ch. 14 (digestive system)

What is the study of the digestive system called?

Gastroenterology (gastro=stomach, entero= intestines, and ology=the study of)

The digestive system (alimentary system) is composed of

Several organs and processes that breakdown, metabolize, and supply nutrients to the body

Gastroenterology consists of

The nature in which food proceeds through the body via peristalsis, or the wavelike muscle contractions that move food to different processing stations in the digestive tract

Stomat/o

Mouth

Dent/o, odont/o

Teeth

Glass/o, lingu/o

Tongue

Cheli/o

Lips

Gingiv/o

Gums

Esophag/o

Esophagus

Pharyng/o

Pharynx

Gastr/o

Stomach

Enter/o

Intestine

Duoden/o

Duodenum

Jejun/o

Jejunum

Ile/o

Ileum

Colon/o

Colon

Sigmoid/o

Sigmoid colon

Rect/o

Rectum

Proct/o

Anus and rectum

Hepat/o

Liver

Cholecyst/o

Gallbladder

Chole

Gall

Cyst/o

Bladder

Pancreat/o

Pancreas

Saliv/o

Salivary glands

What is digestion?

the process of breaking down foods into nutrients that can be absorbed by cells

What is absorption?

The passing of digested nutrients into the bloodstream cycle primarily occurs in small intestines

What is elimination?

The conversion of any residual material from a liquid to a solid and removal of material from the alimentary Canal via defecation

What does the digestive system consist of?

The alimentary canal (digestive tract or gastrointestinal tract) and several accessory organs

How does food travel through the digestive tract

Through the mouth, passes through the pharynx an esophagus and into the stomach, then into the small intestine and large intestine or bowels, and then into the anal canal

What does the alimentary canal extend from

The mouth to the anus

What is the four layers of the alimentary canal aid in

Peristalsis, the movement of chyme

Function of digestive enzymes

Convert complex proteins into amino acids, compounds that can be absorbed by the body

What are complex sugar is produced to

Glucose and other simple sugars

What are fat molecules reduced to?

Fatty acids and other substances through the actions of digestive enzymes

On average, how long does food digestion take?

20 to 48 hours

Where does digestion begin

In the mouth, pharynx, and esophagus

What does the mouth do?

With the help of the tongue, teeth, and lips, it breaks down food into smaller particles, while mixing it with saliva, which is secreted from the salivary glands→ this process is called mastication

Function of lips

Since the food that is about to enter the mouth

What happens when food is taken into the oral cavity/mouth?

It is chewed with the help of the muscle muscles of the cheeks (the walls of the oral cavity) and the tongue (which moves food during mastication/ chewing)

What is the last mechanical process that takes place in the mouth?

Deglutition (swallowing)

What does the tongue contain?

Papilla, small raised area areas that contain taste buds ) cells that provide the sensation of taste)

What is the frenulum

The mucous membrane that connects the tongue to the floor of the mouth

What is at the back of the tongue?

Lingual tonsils; two rounded mounds of lymphatic tissue that play an important role in the immune system

What is the hard pallet?

Formed the roof of the mouth; the heart interior part of the pallet with irregular ridges of mucous membranes called rugae

What is the soft palette?

Formed through the mouth; the soft poster your part of the pallet

What is the uvula?

Located on either side of the back of the mouth; rounded masses of lymphatic tissue

What is Palatine tonsils?

The fleshy sockets that hold teeth

What is salivary glands

Three sets that surround the oral cavity that secretes saliva, a fluid containing enzymes such as amylase (an enzyme that begins the digestion of carbohydrates) that aid in breaking down food

Where does food travel after the mouth?

Through the throat or pharynx (both food and air share this passage away)

What is the epiglottis

When we eat and swallow food, this flap of tissue cover covers the trachea until the food is moved down into the esophagus

what happens as the food swallowed his advanced towards his stomach by the paristaltic wave

The cardiac sphincter will open briefly, once food is in the stomach it will close→ this prevents reflux (backflow) and regurgitation or emeis (vommiting)

What happens every time more food comes through the esophagus into the stomach

The muscles relax and allow food to pass

How much content can the human stomach hold?

1 liters

What happens once the food leaves mouth and passes through the esophagus

It reaches the stomach

Function of the stomach

The further breakdown, food particles; initiate protein digestion; and mix it with needed enzymes before moving onto the small intestine

What is any disease of the stomach?

Gastropathy

What is the enzyme pepsin

In gastric juice that begins protein digestion

What is gastric juice produced by?

Gastric glands, which are stimulated to produce pepsin continuously, but in varying amounts depend, depending on the amount of food being absorbed

What are the four regions of the stomach?

Cardiac region, fundus, body, and pylorus

What is the cardiac region?

The region closest to the heart, is where the cardiac sphincter allows food to enter the stomach and prevents regurgitation. If the cardiac sphincter does not close completely or fails to remain closed, stomach juices will splash into the esophagus where there is no protective lining (heartburn!

What is the pylorus

The upper, rounded portion of the stomach

What is the body of the stomach

The middle portion

What is the pylorus?

The narrowed bottom part of the stomach, has a powerful circular muscle at its base, the pyloric sphincter (controls the emptying of the stomach’s contents into the small intestine)

Characteristic of stomach juices

Extremely aesthetic allow, allowing than intended just food

What is the lining of the stomach intestine served to protect?

The cells from being affected by the digestive juices in the stomach; the lining is relatively thick with many folds of mucous tissue called rutae

What happens as the stomach fills up?

The wall distends and the folds disappear

What is chyme

After eating, the muscular movements of the stomach, and the mixing of food with gastric juice is form a semi fluid mass called chyme

How long is the entire alimentary canal

8 m or 27 feet

What is the small intestine?

A tube like organ that extends from the pylorus to the beginning of the large intestine/colon; is the longest tube in the body and takes up the majority of the abdominal cavity

This is where the majority of the nutrient absorption in the body occurs

What are the three sections of the small intestine?

Duodenum, jejunum, ileum

What is the large intestine/colon

Larger in diameter than the small intestine in extends to the rectum

Function of the colon

To reabsorb the water, salt, water, soluble, nutrients, and electrolytes from digested and undigested food particles (the remaining solid waste or feces is the excreted in the body)

What are the three main sections of the colon

Ascending, transverse, and descending

Beginning of a colon is the cecum, the insect of a colon is the sigmoid colon

What is the duodenum

About 10 inches long. In it chime mixes with bile to aid in fat digestion; with pancreatic juice to aid in the digestion of starch, proteins, and fat, and with intestinal juices to aid in the digestion of sugar/glucose.

What do glands in the duodenum do

Excrete intestinal juices (the juices also help change starch or glycogen into glucose

What is the entire small intestine lubricated by?

Secretion from mucous membranes

What is the small intestine lined with?

Villi (s. Villus), tiny, one self thick finger like projections with capillaries through which digestive nutrients are absorbed into the bloodstream and lymphatic system.

What is the jejunum

An 8 foot long section of the small intestine in which that digestive process continues

What is the ileum

Connect the small intestine to the large intestine

What is at the bottom of the ileum

The ileocecal sphincter muscles that relax to allow undigested and un absorbed food material into the large intestine in fairly regular waves

What do other muscular contraction do

Segment the ileum and prevents waste of material in the large intestine from backing up into the small intestine

Where does the smallest lie

Within the abdominopelvic cavity

What is the small intestines held in place by?

The mesentery, a membrane tissue that attaches both small and large intestine to the wall at the dorsal part of the abdomen

Where does absorption or passage of materials through the wall to the bloodstream) begin

The small intestine

How long does chyme take to travel through the small intestine before enters the large intestine

1 to 6 hours

How large is the large intestine?

5 feet long

What is the cecum?

About attached to the bottom of the ileum of the small intestine

What is the three openings of the cecum?

One from the ileum into the cecum, one from the cecum into the colon, and another from the cecum to a wormlike pouch on the side (appendix or the vermiform appendix)

What is the appendix filled with?

Lymphatic tissue, but is considered an appendage, an accessory part of the body that has no central function because it no longer has a role in the digestive process

What can happen to the appendix?

It can become inflamed and may require surgical removal

What happens within the cecum

The process of turning material into my side, waste/species begin, as water in certain necessary substances are absorbed back into the bloodstream (as water is removed, the semi solid mass is formed and moves into the colon)

What are the divisions of the colon

The ascending colon (extends upward from the cecum to a place under the liver, where it makes a right angle bend known as hepatic flexure)

Transverse colon (continues across the abdomen from the left to right, where it makes a right angle bend, the splenic flexure, toward the spleen)

Descending colon: extends down to the rim of the pelvis, where it connects to the sigmoid colon

What is the sigmoid colon?

NS shaped body that goes across the pelvis to the middle of the sacrum , we are connected to the rectum

What is the rectum?

Attaches to the anal canal

What happens in the rectum?

Feces/stool, then passes from the anal canal to the anus (the anus and anal canal open during the release of feces from the body called defecation)

How long does un digestible waste products from digestion usually remain in the large intestine

12 to 24 hours

What is the liver?

The largest abdominal organ in the body thats most important digestive function is bile secretion

Lies in the upper right abdominal cavity just below the diaphragm

What is the gallbladder?

A small pair shaped sack that lies protected against the inside surface of the liver; acts as a storage for bile until it is needed for digestion

What is the pancreas?

Closely attached to the small intestine and responsible for secretion of pancreatic juice; pancreatic juice, compose of enzymes, metabolize, fats, carbohydrates, and proteins