Chapter 21: Digestion単語カード | Quizlet

What are four processes of digestion?

Digestion

Motility

Secretion

Absorption

What is digestion?

chemical and mechanical breakdown of food into absorbable units

What is secretion?

movement of material from cells into lumen or ECF

What is absorption?

movement of material from GI lumen to ECF

What is motility?

movement of material through the GI tract as a result of muscle contraction

What are the components of the digestive system?

Oral cavity

Salivary glands

Esophagus

Liver

Stomach

Pancreas

SI

LI

Rectum

What are two ways food is moved throughout the body?

Peristalsis

Segmentation

What is peristalsis

wave-like muscle contractions

When is peristalsis used?

To move move your food down the GI tract

Segmentation

Random contractions along the GI tract

When is segmentation used

To mix your food in the GI tract

What is total input and output of the lumen?

9 L/day

What are the two ways we input fluid into the lumen?

Ingestion (food and drink) - 2 L/Day

Secretions (from cells to lumen) - 7 L/Day

What are the two ways we remove fluid from the lumen?

Absorption

Excretion

What cells line the stomach?

Parietal Cells

What do parietal cells secrete?

HCl

What the transporters on the apical and basolateral side of the parietal cell?

basolateral side - Chloride and bicarb (antiporter)

Apical - K+ H+ ATPase, Chlorine transporter

What are the two functions of the pancreas?

endocrine and exocrine

What are the exocrine functions of the pancreas?

secretes pancreatic juice and digestive enzymes

What are the endocrine functions of the pancreas?

To secrete hormones like glucagon and insulin

What do duct cells in the pancreas secrete?

sodium bicarbonate

What is the CFTR channel?

Controls the movement of water in cells which produce mucus, sweat, saliva, tears, and digestive enzymes.

Where is the CFTR gene located?

pancreas

What happens when the CFTR channel is mutated?

Cystic Fibrosis

What is the function of the liver

Make bile

What is the function of the gallbladder

Stores bile

What are the two vessels of transport for the liver?

The hepatic portal vein and the hepatic duct

Where does the Hepatic duct go?

Away from the liver

Where does the Hepatic portal vein go?

To the liver

Sphincter of Oddi

Where the ducts of the pancreas and the gallbladder meet up and enter the duodenum

Pyloric Valve

controls the release of stomach contents into the intestine. So it's closed when food is in the stomach being digested

What are the two regulators of the digestive system?

The cephalic brain

Enteric nervous system

Sugars begin as ____________________ and are broken down into ______________________ and then into _________________ by __________________ .

polysaccharide

dissaccharide

Monosaccharide

amylase

The from of sugars which are able to cross the epithelium, which means they can be digested, are ______________________.

Monosaccharides

Once carbs or proteins become monosaccharides or amino acids, they travel to the liver via.......

The hepatic portal vein

Proteins begins as ____________________ and are broken down into ______________________ and then into _________________ by __________________ or _______________

Polypeptides

Dipeptides

Amino acids

Endopeptidases

Exopeptidases

If they are not broken down into AA polypeptides can cross the epithelium via ______________________

Transcytosis

What does an endopeptidase do?

cut peptide bonds in the middle of the polypeptide

What does an exopeptidase do?

cuts the peptide bond at the end of polypeptide

How are fats digested?

Large fat droplets + bile

Micelles via colipase + liapses

Cholesterol into SI cells

Monoglycerides into SI cells - smooth ER makes triglycerides

Cholesterol + protein + Triglycerides to make chylomicrons

Chylomicrons into Golgi - vesicle - exocytosis

into Lacteal to Vena Cava

Digestion of Triglycerides

Monoglycerides + Free Fatty Acids

Bile salts are _________________ which allow emulsficcation

amphipathic

What are micelles made up of?

Bile Salts, phospholipids, mono- and di-glycerides, free fatty acids, cholesterol

In addition to nutrients, the intestines absorb......

Water

Ions

Vitamins

Minerals

What are the three phases of digestion?

cephalic, gastric, intestinal phase

What is the cephalic phase of digestion?

earliest phase of digestion in which the brain prepares the body in anticipation of food (via the thought, smell, or food in the mouth)

During the cephalic phase, the anticipation of food causes GI ___________ and GI _____________.

motility

secretions

During the Cephalic phase the mouth begins digestion ___________________ and _________________.

Mechanically

Chemically

How does the mouth exhibit mechanical and chemical digestion?

Mechanical: Grind, mix & liquefy

Chemical: water, lingual amylase, mucus, and lysozyme

What organ is involved in the gastric phase?

The Stomach

The Stomach has three elements which are involved in the gastric phase?

Storage

Digestion

Protect Walls

Describe the role of storage in the gastric phase?

It has to do with when food was not available so our body holds on to food all the time so you can tap into the nutrients later

Describe the role of digestion in the gastric phase?

Parietal cells - secrete HCl

Chief cells - secrete lipase and pepsin

Describe the role of protecting walls in the gastric phase?

Mucus protects the stomach from digesting itself.

What factors are in place to ensure that your stomach doesn't digest itself?

Gastric Mucus cells secrete mucus, which develops a mucus layer.

The bicarbonate is released by the gastric mucus cells which gets trapped in the mucus, creating a gradient of the buffer which neutralizes the acidic pH of the stomach

What is the intestinal phase?

Where the bolus enters the duodenum

The cephalic input to the CNS leads to the activation of the _______________ ______________ system

Enteric Nervous

When the bolus enters the small intestine, it triggers the activation of the __________ ___________ system, which reduces GI __________ , slows gastric ____________, and causes the release of a mix of stuff from the sphincter ___________.

enteric nervous

motility

emptying - limited chyme entrance rate

Oddi

What is being released from the sphincter Oddi?

Sodium Bicarbonate (neutralizes HCl) - (pancreas)

Bile (gallbadder)

Enzymes (pancreas)

What happens to enzymes when they are released into the lumen of the small intestine?

The enzymes are anchored to the lumen, so that the chyme is broken down passes the enzymes.

Why are enzymes anchored to the small intestine?

Because if the body had to make new enzymes all the time, that would be a lot of wasted energy.

During the intestinal phase, what is the role of the liver?

Make bile to be secreted in the gallbladder and stored

Recycle bile salts (they aren't excreted)

Hepatic system (portal and vein)

What is the role of the Hepatic system?

Breaking down anything harmful before it enters the blood and can reach the lungs

What is the role of the Hepatic portal system?

Direct absorbed nutrients (carbs, protein)

Blood from the left side of the heart is split between which 2 arteries?

Hepatic arteries

Digestive tract arteries

The blood from the liver all goes to the _____________

Right side of the heart.

How much water does the large intestine reabsorb, and how much water does the small intestine reabsorb?

SI - 7.5 L/day

LI - 1.5 L/day

The large intestine stores __________ and the ___________ within the LI make sure that they don't leave at an inappropriate time

feces

sphincter

What is the defecation reflex?

removes undigested feces from the body

defecation reflex is triggered by

It is triggered by the movement of fecal material into the normally empty rectum

Describe the overall process of the defecation reflex?

internal anal sphincter (involuntary) relaxes and peristalsis contractions in the rectum push material toward her anus.

The external anal sphincter (voluntary) - is consciously relaxed if the situation is appropriate

Describe H2O absorption in the Large instestine? (regulation)

Water is regulated in the collecting ducts by managing the number of aquaporins via vasopressin

Describe digestive health related to protection?

M cells

Peyer's patches

Lymphocytes (GALT)

Describe digestive health related problems?

Irritable bowl syndrome

Diarrhea

Vomiting

Ulcers

Heartburn

What is the state of having diarrhea?

The intestinal secretion of fluid is not balance by absorption. So you get watery stools

What are the two ways in which you get diarrhea?

The bacterial toxins cause either

1. disruption to water absorption

2. osmotically active solutes that "hold" water in the lumen

How do you treat diarrhea?

Salt solution via IV so that it draws the water into the cells and out of the lumen

What can prolonged vomiting lead to?

alkalosis - which activates the principle P cells

How are ulcers caused?

H. Pylori

What is the affect of an ulcer?

removing of mucus from protecting the stomach

Describe heartburn as it related to digestive health?

Acid Reflux disease

(the lower esophageal sphincter is too weak to keep acid in the stomach)