digestive system #1

This section of the small intestine is ~8 feet long, is where most digestion occurs, and GALT (peyer's patches) are predominant distally

Jejunum

These glands lie between villi, with continuous epithelium. They are found in the small and large intestine, produce sucrase, maltase, and peptidase. They also have a high rate of mitosis b/c of stem cell reservoir.

Lieburkuhn glands (crypts)

What breaks down triglycerides into free fatty acids and monoglycerides, that enter the villi for absorption?

Pancreatic lipase

The cells found at the base of crypts (lieburkuhn glands) that release lysozymes, defensins, and phospholipase A2 when exposed to bacteria are?

Paneth cells

This section of the small intestine has a submucosa that contains clusters of mucous glands (brunners's), produces alkaline mucous to neutralize stomach acidity, and prepares food for pancreatic enzyme

duedenum-iron absorption occurs here

In the digestion of fat, what refers to the process when bile salts hold triglycerides in the watery surroundings?

emulsification

What are the functions of the stomach?

exocrine/endocrine chamber, blends food into chyme, digests CHO and Ptn, produces acid, produces gastric lipase, and absorption (water, alcohol, drugs)

The autonomic innervation of the small intestine where sympathetic and parasympathetic NS modulate its counterpart is known as

extrinsic (counterpart is intrinsic)

What is the function of the lamina propria in the mucosa?

first line of defense, and the production of IgA by B-lymphocytes

A protrusion of a part of the stomach into the thorax through the diaphragm, which is mostly asymptomatic other than resistant heart burn is called a

hiatus hernia

Enteroendocrine D-cells (inhibit/stimulate) gastrin as a result of HCl--negative feed back.

inhibit

The autonomic innervation of the small intestine where the Myenteric plexus (auerbach's; Mechanoreceptors) which gives off the submucosal plexus (messiness'; chemoreceptors) is known as

intrisic

In the body/fundus, this layer has mucus cells, oxyntic (parietal) cells, plus some stem cells.

isthmus

In the stomach, you find stem cells in the __, in the small intestine you find them in the __.

isthmus, crypts

Lymphoid tissue in the large intestine exists within what layer?

lamina propria

The villi of the small intestine (.5-1.5mm protrusions into the lumen) have a core of __ __ in each villus

lamina propria

The main function of this part of the digestive tract is to get water back (also formation of fecal mass, and mucus production).

large intestine

ICCs produce the __ __ __ in between meals that prevents upstream of colonic bacteria, and causes the rumbling sounds associated with hunger.

migrating myoelectrical complex (MMEC)

The innermost, lubricated lining, that consists of an epithelium (cellular lining of the tube), Lamina propria (loose CT), and Muscularis mucosa (mucosal lining) is called what?

mucosa (mucous membrane)

What are the four layers of the intestine?

mucosa, submucosa, muscularis, and serosa

The layer involved in peristalsis, with spirally oriented smooth muscle cells (inner circular outer longitudinal) is called the

musclaris

What kind of cells line the esophageal walls

non-keratinized stratified squamous epithelium

What muscles of the esophagus are contracted voluntarily upon swallowing (resembles peristalsis)

oropharyngeal muscles

What breaks down carbohydrates into oligosaccharides?

pancreatic amylase (brush border enzymes break oligo to mono that can be absorbed)

Chief (zymogenic) cells produce what?

pepsinogen-->pepsin in the acidic lumen; lipase

In this section of the stomach, glands have longer pits and shorter secretory sections, secrete mucus and lysozymes, and has a thickened middle layer (circular muscle) that forms the sphincter.

pylorus (pyloric sphincter)

From the GE junction, epithelial tissue will remain simple columnar until the __ __

rectoanal junction

There are no mucosal folds in the large intestine except where?

rectum

What are the functions of the epithelium of the mucosa?

selective permeability to molecules and electrolytes, digestion, absorption, hormone secretion, and the production of mucus for lubrication

The thin layer of loose connective tissue covered with simple squamous epithelium (mesothelium), that is continuous with mesenteries and peritoneum is the

serosa (adventitia)

The enteroendocrine cells of the small intestine produce:

serotonin, somatostatin, secretin, gastrin, motilin, VIP, choecystochynin

What are the 5 ways reflux is prevented by GEJ mechanisms?

1-lower esophageal sphincter pressure, 2-acute angle at the junction (flap valve), 3- diaphram contraction, 4- abdominal pressure is greater than gastric pressure, 5- unidirectional peristalsis of esophagus

What are the three parts of the small intestine?

Duodenum, Jujenum, Ileum

This cell type is at the neck and base of gastric glands, secretes serotonin, and are known to develop into carcinoid tumors.

Eneteroendicrine cells

These cells are absorptive, present in villi, can be found in glands, are columnar cells, with basal nuclei and apical brush (striated borders)-->microvilli

Enterocytes

The lamina propria and submucosa in the large intestine are rich in what?

GALT

Chronic reflux due to less pressure at the LES is known as

GERD

Rather than the lumen, the site of absorption in the small intestine occurs in the __ that covers the brush border.

Glycocalyx-->dipeptidases, disaccharidases

Oxyntic (parietal) cells produce what?

H+ and Cl-

Oxyntic (parietal) cells are stimulated by what to release the contents of their vesicles (HCl)

Histamine, ACh, or gastrin

What are the parts of the large intestine?

Ileocecal valve, acending, transverse, decending, sigmoid colon, rectum, anus

This section of the small intestine contains the last 11 feet before the iliocecal valve, absorbs B12, recycles bile salts, and is involved in the final stages of protein and CHO digestion, with the most peyers patches.

Ileum

The origin of gastrointestinal stromal tumors is:

Interstitial cells of Cajal (ICC)

The pacemakers of the gut movements from the stomach down, located between the nerve ending and the smooth muscle cells are called:

Interstitial cells of Cajal (ICC)

The jejunum is responsible for most of the absorption of nutrients except:

Iron-duodenum; B12-terminal ileum; Na, Fructose, H20, and lipids--throughout the GIT

What are the parts of the stomach?

cardia, body/fundus, pylorus

What do all four parts of the stomach produce?

cardia-mucus, body/fundus-acid+enzymes+mucus, pylorus-mucus+gastrin

What glands are located in the lamina propria near the stomach?

cardiac

How long and how much surface area does the small intestine have?

20 feet long, one acre surface area

Metaplasia of the lower esophageal mucosa (simple columnar instead of simple stratified squamous) is known as?

Barrett's esophagus (premalignant-->cancer esophagus)

In the body/fundus, this layer has oxyntic (parietal) and chief cells

Base

This part of the stomach is where most of the digestion takes place, with three layers that make glands (isthmus, neck, base).

Body/fundus--has more extensive branding (3-7 per pit)

What section of the stomach has a circular band (2cm wide), with simple columnar epithelium folded into tubular protrusions into the lamina propria, forms pits on the surface, and produces lots of mucus?

Cardia

In the body/fundus, this layer has mucus neck cells dispersed between oxyntic (parietal) cells

Neck

Enteroendocrine G-cells (inhibit/stimulate) parietal cells directly and indirectly through ECL--histamine production.

Stimulate

The disorder that is a result of relaxation failure at the lower esophageal sphincter (when food doesn't travel the entire length of the esophagus, gets trapped) is called

achalasia

__ transport of NaCl outside the basal border is followed by __ absorption of water from the lumen

active, passive

Exopeptidases of the pancreas are __ and _, which split one amino acid at a time from the carboxy or amino ends of the peptide chain.

carboxypeptidase and aminopeptidase

Glands in the stomach empty into gastric pits, which have what type of cell within?

simple columnar epithelia (of the mucosa, producing alkaline mucus, forms hydrophobic gel)

What type of epithelium forms mucosal glands?

simple columnar epithelium, which are highly rich in goblet cells

2 cm from the anus, the mucosa becomes __ __, with abundance of veins in submucosa.

stratified squamous

In the GE junction, there is an abrupt change from protective __ __ epithelium to __ __ __ epithelium.

stratified squamous, secretory simple columnar

What is the distribution of muscle types in the musculosa of the esophagus?

striated-->upper part, mixed--> middle part, smooth-->lower part (forms sphincter)

The layer of the intestine that consists of dense connective tissue for support is called what?

submucosa

Where are the mucous secreting cells in the esophagus?

submucosa

What is the function of the muscular is mucosa in the mucosa?

this layer consists of 2 thing smooth muscle layers between the mucosa and submucosa (inner circular outer longitudinal) that function in mucosal gliding against the tough submucosa. Moves and mixes the lumen content

Enteropeptidases of the stomach and pancreas are __ and __, which cleave proteins into smaller peptides.

trypsin and chymotrypsin

What are esophageal glands' role?

unique to the esophagus, these glands aid in lubricating so swallowing happens fast

Metaplasia

when 1 type of cell becomes another (both types normal, but it dangerous and considered to be pre-cancerous)