digestive Flashcards
The digestive tract is also called the
alimentary canal
the order of the structures that food passes through (including the parts of each structure)
Oral cavity -> Oropharynx -> Laryngopharynx -> Esophagus -> Stomach -> Duodenum -> Jejunum -> Ilium -> Cecum -> Ascending colon -> Transverse colon -> Descending colon -> Sigmoid colon -> Rectum
the functions of the digestive system (samedip)
secretion
absorption
mechanical digestion
excretion
digestion
ingestion
protection
Taking food in (eating)
Ingestion
Physical breakdown of food into smaller pieces
Mechanical Digestion
Breaking large food molecules into small, absorbable nutrient molecules (breaking chemical bonds via hydrolysis reactions
chemical digestion
Releasing substances into the alimentary canal to help in digestion
Secretion
Releasing wastes into the alimentary canal for the purpose of removal from the body (putting wastes in the bile) or releasing wastes from the body (defecation of feces)
excretion
Moving nutrients, water, vitamins, etc from the alimentary canal into the body (into circulation)
Absorption
Vomiting & diarrhea reflexes protect the body from pathogens or toxins that may be ingested
Protection
Mechanical processing in the oral cavity is called what?
Mastication
Name the three pairs of salivary glands:
Parotid, Sublingual, submandibular
What 2 enzymes are in saliva? What do they digest? Where do they work?
- Salivary Amylase digests carbs in the mouth
- Lingual lipase digests lipids mostly in stomach
Esophageal glands produce what type of secretions? Why?
Mucous to lubrication/decrease friction
How is food moved down the esophagus?
Peristalsis
What is the function of the lower esophageal sphincter?
To prevents acid chime from entering the esophagus from the stomach
The semiliquid substance produced in the stomach is called
Chyme
the cells present in the gastric glands, what they produce, and the function of the product
- G-Cells: Gastrin: Stimulates gastric secretions, relaxation of pyloric and ileocecal sphincters, stimulates intestinal motility
- Parietal Cells: Intrinsic factor (needed vit B12 absorption in SI), HCl
- Chief Cells: Pepsinogen (proenzyme that becomes pepsin which digests protein), gastric lipase which digests lipids
- Mucous Cells: mucous
G-Cells:
Gastrin: Stimulates gastric secretions, relaxation of pyloric and ileocecal sphincters, stimulates intestinal motility
Parietal Cells:
Intrinsic factor (needed vit B12 absorption in SI), HCl
Chief Cells:
Pepsinogen (proenzyme that becomes pepsin which digests protein), gastric lipase which digests lipids
Mucous Cells:
mucous
how HCl and pepsin enter the lumen of the stomach (how do we ensure they don’t damage the cells responsible for making them or the gastric glands):
HCl is secreted as H+ and Cl_ ions, Pepsin is secreted as the inactive pepsinogen (activated in lumen due to acidity
Overall, what nutrients get digested in the stomach?
proteins and lipids
The “mixing bowl” that receives chyme from the stomach and secretions from the liver and pancreas is the…
Duodenum
Most chemical digestion and nutrient absorption occur in what part of the digestive tract? (be specific)
Jejunum
Villi are …. Their function is to…
Finger-like projections of the mucosa in the small intestine… Increase surface area of SI
Microvilli are …. Their function is to
Tiny projections of plasma membrane of cells in the SI…. Increase Surface area of SI
A lacteal is a ____ It is important in the absorption of____
Lymphatic capillary
lipids/fat soluble vitamins (ADEK)
Brunner glands are ___________ glands in the _________. What is the major purpose of their secretion?
mucous glands
duodenum
Secrete an alkaline mucous to protect duodenum from acidity of chyme
What are brush border enzymes? Where are they? What do they do (typically and after shed)?
integral membrane proteins in the small intestine. They initially digest materials in contact with the brush border. They digest materials in the lumen after they are shed.
When food enters the duodenum ____and_____ stimulate secretions from the pancreas and gallbladder. They also inhibit gastrin and cause pyloric sphincter contraction.
CCK & Secretin
stimulates gallbladder contraction and relaxation of the hepatopancreatic sphincter so that bile is released into the duodenum.
CCK
stimulates secretions form the pancreas
Secretin
Which class of enzymes get secreted as inactive proenzymes?
Proteolytic
Lacteals are important in the absorption of what type of nutrient?
Lipids and fat soluble vitamins (ADEK)
Pancreatic juice is made by what cells?
Acinar Cells
Know the type of food that each of the pancreatic enzymes breaks down…
lipase- lipids, amlase-sharch/carbs, protease/proteolytic enzymes-proteins, ribonuclease-RNA, deoxyribonuclease- DNA)
lipase
lipids
amylase
starch/carbs
protease/proteolytic enzymes
proteins
ribonuclease
RNA
deoxyribonuclease
Dna
Pancreatic juice has ____ to neutralize____
carbonates
acid chyme
What digestive organ produces bile:
liver
What is the function of the gallbladder?
Store and concentrate bile then secrete into duodenum
How do bile salts aid in digestion?
Break lipid drops into smaller droplets (emulsification). Provides greater SA for digestive enzymes.
Most monosaccharides (glucose) and amino acids are absorbed from the GI tract by ____
sodium transporters
___and___ are absorbed from the GI tract by sodium transporters
monosaccharides (glucose) and amino acids
Fatty acids diffuse through the cell membrane of absorptive cells and are eventually packaged into
chylomicrons (along with fat soluble vitamins, steroids, and other lipids)
Water is absorbed ____along its____
passively
osmotic gradient
Describe the wall of the large intestine
no villi, dominated by mucous glands, NO enzymes produced, longitudinal muscle reduced to the band called the taeniae coli
What breaks down food in the large intestine?
bacteria
What vitamins are produced in the large intestine?
Vit K, B5, biotin
Water reabsorption form the GI tract occurs where?
Large intestine (Cecum to the transverse colon)
What would the result be if stool was moved more quickly from the cecum to the transverse colon?
Watery stool because of decreased water reabsorption
“segmentation” movement that mixes material in the GI tract
Haustral churning
Powerful peristaltic contractions that move fecal material from transverse colon towards rectum
Mass movements
