PNB 2265-Digestive System

benefit of having a one-way digestive system

allows for additional consumption before the complete digestion of a previously consumed item

accessory organs of the digestive system

salivary glands, liver, pancreas, gallbladder

peritoneum

double-layered membrane surrounding the abdominal organs; specialized serous membrane that folds in on itself and creates subcompartments

greater omentum

a peritoneal fold that stores a lot of adipose tissue; holds a lot of visceral body fat

Which of the following is the correct order of the tissue layers of the digestive system from the outside (abdominal wall) into the lumen?

a. serosa, muscularis, mucosa, submucosa

b. serosa, muscularis, submucosa, mucosa

c. mucosa, muscularis, submucosa, serosa

d. muscosa, submucosa, muscularis, serosa

serosa, muscularis, submucosa, mucosa

Which tissue layer of the digestive tract acts is the outermost layer and acts as a connective tissue wrapper for the GI tract?

a. mucosa

b. submucosa

c. muscularis externa

d. serosa

serosa

Which tissue layer of the digestive tract is itself made up of an outermost longitudinal layer and an innermost circular layer?

a. mucosa

b. submucosa

c. muscularis externa

d. serosa

muscularis externa

Which tissue layer of the digestive tract contains the myenteric plexus, the major site of sensory and motor information in the GI tract?

a. mucosa

b. submucosa

c. muscularis externa

d. serosa

muscularis externa

True or False: The myenteric plexus is the only sensory-motor regulator of the gut

False, the digestive system is regulated by the parasympathetic nervous system as well

Which digestive system layer is made up of three sublayers: the muscularis mucosae, lamina propria, and epithelium?

a. mucosa

b. submucosa

c. muscularis externa

d. serosa

mucosa

Which mucosal layer is a small layer of smooth muscle that creates the villi of the small intestine when it contracts?

a. muscularis mucosae

b. lamina propria

c. epithelium

muscularis mucosae

Which mucosal layer is associated with white blood cells that prevent pathogens from entering the body via the digestive system (galt)?

a. muscularis mucosae

b. lamina propria

c. epithelium

lamina propria

Which mucosal layer contains most of the secretory and absorptive cells of the digestive system?

a. muscularis mucosae

b. lamina propria

c. epithelium

epithelium (cells that make up the lumen)

peristalsis

efficient forward movement of the bolus through the GI tract caused by pressure gradients created by contracted smooth muscle behind the bolus and relaxed smooth muscle in front of the bolus

segmentation

produces a back-and-forth movement of food particles that is efficient for mixing food contents with digestive secretions; primarily takes place in the small intestine

True or False: Although smooth muscle lacks striations/sarcomeres, it still contains actin and myosin

true

Smooth muscle filaments slide ____________ when contracting.

a. toward

b. away

away

tonic contractions

long contractions; sphincter muscles undergo these contractions

phasic contractions

quick contractions; peristalsis and segmentation

Secretion and absorption take place in the ___________ layer of the GI tract

a. serosal

b. muscularis external

c. submucosal

d. mucosal

mucosal

___________ refers to the movement of molecules into the lumen whereas ____________ refers to movement of molecules into the interstitial fluid and the blood

a. secretion; absorption

b. absorption; secretion

secretion; absorption

function of the brush border

to maximize the membrane surface area to allow for more efficient nutrient transport

Carbohydrate digestion begins in the:

a. mouth

b. stomach

c. small intestine

d. large intestine

mouth

the 3 disaccharides

sucrose, lactose, maltose

True or False: glucose and fructose are not only isocaloric, but also isometabolic

False, they are not metabolized the same way

Enzymes that break down proteins are called __________

a. amylases

b. peptidases

c. lipases

d. chylomicrons

peptidases

_______________ catabolize proteins by breaking down the ends of polypeptide chains, whereas ______________ break down proteins by cutting polypeptide chains in the center.

a. endopeptidases; exopeptidases

b. exopeptidases; endopeptidases

exopeptidases; endopeptidases

Proteins can be absorbed without being broken down at all via ______________

a. phagocytosis

b. endocytosis/exocytosis

endocytosis/exocytosis

To emulsify fat droplets and become amphipathic/water soluble, the droplets get coated with __________

a. bile

b. interstitial fluid

c. plasma

bile

micelle

a re-formed particle of free fatty acids and monoglycerides that can cross the plasma membrane via diffusion

chylomicrons

the class of lipoproteins that transport lipids from the intestinal cells to the rest of the body in order to absorb fats

lacteals

specialized lymph vessels in the small intestine that absorb fat into the bloodstream because chylomicrons are too big to be absorbed into the capillaries

True or False: Carbohydrates and proteins are able to be directly absorbed into the bloodstream whereas lipids must pass through the lymphatic system before entering the circulation

true

hepatic portal vein

A vein connecting the capillary bed of the intestines with the capillary bed of the liver. Allows absorbed nutrients from the intestines to be delivered first to the liver before being transported throughout the circulatory system.

alcohol flush syndrome

condition that causes an individual to feel sick after consuming alcohol because of a lack of the enzyme alcohol dehydrogenase

The _____________ peritoneum lines the abdominal wall

a. visceral

b. parietal

parietal

The _____________ peritoneum covers the surface of the organs

a. visceral

b. parietal

visceral

All three simple sugars, glucose, fructose, and galactose, are transported out of the intestinal epithelial cell and into the bloodstream through what transporter?

a. SGLT1

b. GLUT5

c. GLUT2

GLUT2

Through what transporter on the apical membrane of an intestinal epithelial cell does fructose enter the cell?

a. SGLT1

b. GLUT5

c. GLUT2

GLUT5

Through what transporter on the apical membrane of an intestinal epithelial cell does glucose, galactose, and sodium enter the cell?

a. SGLT1

b. GLUT5

c. GLUT2

SGLT1