Gastrointestinal Flashcards
What is the role of the palate?
Separates the mouth from the nasal passages, allowing breathing and chewing simultaneously
What is the role of the uvula during eating?
Seals of the nasal passages during swallowing
What are the functions of the tongue?
Guides food
Speech
Swallowing
Taste buds
Describe the pharynx
Common passageway for respiratory and digestive systems
Tonsils on side walls - lymphoid tissue
Where are the salivary glands located?
Parotid - below ear, over the masseter
Submandibular - under lower edge of mandible
Sublingual - floor of mouth under tongue
What are the functions of saliva?
Lubrication
Solvent (taste)
Antibacterial
Digestion of complex carbohydrate (amylase)
Neutralization of acid (bicarbonate)
Facilitates suckling of infant (fluid seal)
Which peptide hormones are secreted by the duodenum?
Gastrin - G cells
Cholecystokinin - I cells
Secretin - S cells
Motilin - M cells
Glucose-dependent insulinotropic peptide (GIP), incretin - K cells
Glucagon-like peptide-1 (GLP-1), incretin - L cells
Which peptide hormones are secreted by the jejunum?
Cholecystokinin - I cells
Motilin - M cells
Glucose-dependent insulinotropic peptide (GIP), incretin - K cells
Glucagon-like peptide-1 (GLP-1), incretin - L cells
What type of receptors do the peptide hormones secreted by the small intestine act on?
G-protein coupled receptors
What are the control mechanisms for secretion of succus entericus?
Increase secretion
Distension/irritation
gastrin
CCK
secretin
parasympathetic
Decrease secretion
sympathetic
What does the succus entericus contain?
Mucus (from goblet cells)
Aqueous salt (crypts)
no digestive enzymes
What membrane proteins does secretion of the succus entericus involve?
Na+/K+ ATPase
Na+/K+/2Cl- co-transporter
Chloride channel
What is the BER and what triggers it?
Basic Electrical Rhythm
Interstitial cells of Cajal - pacemaker cells
How is the chyme mixed in the small intestine?
Segmentation - chopping movements back and forth created by contraction of circular muscle
What triggers segmentation in the empty ileum?
Gastroileal reflex - gastrin released from stomach
What is the Migrating Motor Complex?
Perilstalsis occuring between meals every 90-120 minutes
Strong peristaltic contraction from stomach to ileocaecal valve
which clears the small intestine of undigested debris, mucus and sloughed epithelial cells
What triggers the Migrating Motor Complex?
Motilin
What suppresses the Migration Motor Complex?
Gastrin
CCK
Why might macrolide antibiotics such as erythromycin cause GI disturbance?
They mimic the action of motilin
What are the contents of pancreatic juice?
Digestive enzymes
aqueous NaHCO3-
Which pancreatic cells secrete digestive enzymes?
Acinar cells
Which pancreatic cells secrete bicarbonate solution?
Duct cells
How are enzymes stored in the acinar cells of the pancreas?
Zymogen granules
Which proteases are secreted in proform by the pancreas?
trypsin(ogen)
chymotrypsin(ogen)
(pro)carboxypeptidase
