Mcat Bio terms chp 9

alimentary canal

Mouth to anus and is sectioned off by sphincters

ghrelin

secreted by the stomach and pancreas and it stimulates the feeling of hunger

Leptin and cholecystokinin

stimulate the feelings of satiety

mastication

= chewing

helps to increase the surface area-to-volume ratio of the food, creating more surface area for enzymatic digestion as it passes through the gut tube

Ptyalin and Lipase

=salivary amylase

different areas of Pharynx

nasopharynx (behind the nasal cavity), the oropharynx (at the back of the mouth), and the laryngopharynx (above the vocal cords)

emesis

-vomiting

stomach fundus and body

= contain gastric glands

stomach antrum and pylorus

=contain pyloric glands

rugae

the lining of the stomach thrown into folds

mucous cells

produce the bicarbonate-rich mucus that protects the muscular wall from harsh acidic and proteolytic environment of the stomach

zymogen

form of pepsin, a proteolytic enzyme.

chief cells

secrete pepsinogen

parietal cells

secrete hydrogen ions in the stomach in the form of hydrochloric acid

Intrinsic factors

Secreted by parietal cells. This is a glycoprotein involved in the proper absorption of vitamin B12.

G-cells and Gastrin

pyloric glands contain G-cells which secrete gastrin

Gastrin induces the parietal cells in the stomach to secrete more HCL and signals the stomach to contract, mixing its contents.

Brush-border enzymes

These are like disaccharidases (maltase, iso-maltase, lactase and sucrase)

-break dimers and trimers of biomolecules into absorbable monomers.

Aminopeptidase

peptidase secreted by glands in the duodenum that removes the N-terminal amino acid from a peptide.

Dipeptidases

cleave the peptide bonds of dipeptides to release free amino acids.

Enteropeptidase (formerly called enterokinase)

enzyme critical for the activation of trypsinogen, a pancreatic protease, to trypsin.

• It also activates procarboxypeptidases A and B to their active forms.

Trypsin

initiates an activation cascade

Secretin

• peptide hormone

• Regulates the pH of the digestive tract by reducing HCl secretion from parietal cells and increasing bicarbonate secretion from the pancreas.

• Secretin is also an enterogastrone, a hormone that slows motility through the digestive tract.

cholecystokinin (CCK)

This peptide hormone stimulates the release of both bile and pancreatic juices and also acts in the brain, where it promotes satiety.

acinar cells

bulk of the pancreas

• these are exocrine cells

albumin

a protein that maintains plasma oncotic pressure and also serves as a carrier for many drugs and hormones, and clotting factors used during blood coagulation.

chylomicrons

triglycerides and esterified cholesterol molecules are packaged into these

ileocecal valve

the site of attachment of the appendix