Iiii Flashcards
What do exocrine glands secrete?
Substances through ducts or tubes onto a body surface or into a cavity.
Give examples of exocrine glands.
- Salivary glands
- Prostate gland
- Milk glands
What are endocrine hormones?
Chemicals secreted by endocrine glands directly into the blood.
How are endocrine hormones classified?
According to their activation site.
What are non-target hormones?
Hormones that affect many cells throughout the body; e.g., insulin, epinephrine, GH, somatotropin.
What are target hormones?
Hormones that affect specific cells or target tissues; e.g., parathyroid hormone, gastrin.
True or False: Endocrine hormones affect all cells in the body.
False.
What was the first method used to study the role of hormones?
Removing an organ and observing the effect on the animal.
What significant observation was made in 1889 regarding the pancreas?
Ants were gathering in the cages of dogs with removed pancreases, indicating a hormone was regulating blood sugar.
What are the two main types of hormones?
- Steroid hormones
- Protein hormones
What are steroid hormones made from?
Cholesterol - complex rings of C, H, O.
Are steroid hormones soluble in water?
No, they are not soluble in water but are soluble in fat.
How do steroid hormones interact with target cells?
Diffuse from capillaries to target cell and combine with receptors in the cytoplasm.
What do protein hormones contain?
Chains of amino acids.
Are protein hormones soluble in water?
Yes, they are soluble in water.
How do protein hormones activate their function?
Combine with receptors on the cell membrane and activate production of adenylyl cyclase.
What is the role of the pituitary gland?
It is the ‘master’ gland that exercises control over endocrine glands.
What are the two lobes of the pituitary gland?
- Posterior Lobe
- Anterior Lobe
What hormones does the posterior lobe of the pituitary gland store and release?
- ADH
- Oxytocin
What does the anterior lobe of the pituitary gland produce?
Its own hormones, regulated by hypothalamus nerves.
What is the function of glucagon?
Stimulates the liver to release glucose stores to the blood.
What triggers the release of insulin?
High blood glucose levels.
What is the effect of insulin on blood glucose?
Increases the rate cells take up glucose, thus lowering blood glucose.
What is somatostatin?
A hormone that inhibits the effects of glucagon and insulin.
