Human Physiology - Digestive System

Study Notes

Stomach Control

Neural stimulation triggers stomach endocrine cells to release gastrin.
Gastrin stimulates the secretion of gastric juices (HCl, mucus, water, pepsin).
Positive feedback loops prepare the stomach for food intake.

Chyme Entry and Hormonal Responses (Duodenum)

Chyme entering the duodenum triggers the release of CCK from duodenal endocrine cells.
CCK stimulates the gallbladder to release bile for lipid emulsification.
CCK levels are directly proportional to chyme levels in the duodenum.
Secretin is released from duodenal endocrine cells in response to chyme entry.
Secretin stimulates pancreatic secretion, including enzyme formation and bicarbonate production.
Secretin levels are proportional to chyme levels in the duodenum.
Bile production and secretion by the liver are not hormonally controlled.

Blood Glucose Homeostasis

Normal blood glucose levels in adults are approximately 3-4.5 mmol/dL.
Elevated levels (hyperglycemia) and decreased levels (hypoglycemia) are abnormal.
Hyperglycemia can cause tissue damage, glaucoma, swelling, or neurological issues.
Hypoglycemia can lead to problems with temperature regulation, hypotension, and bradycardia.

Post-Meal Blood Glucose

Blood glucose rises a few hours after a meal.
A blood glucose level of 5.0 mmol/dL is a trigger point.

Between-Meal Blood Glucose

Between meals, blood glucose levels drop, triggering the 3.5 mmol/dL level threshold.

Description

Explore the intricacies of the human digestive system in this quiz focusing on stomach control, chyme entry, and hormonal responses in the duodenum. Test your knowledge on how hormones like gastrin, CCK, and secretin regulate digestive processes and maintain blood glucose homeostasis.