Week 2: The Endocrine System Flashcards
What are the factors that affect the responsiveness of a target cell to a hormone?
The hormones concentration, abundance of target cell receptors and influences exerted by other hormones.
How is hormone secretion regulated?
By the nervous system signals, chemical changes in the blood and other hormones.
What is the difference between the pituitary gland and the hypothalamus?
The hypothalamus is the major link between the nervous and endocrine system.
The pituitary gland secretes several hormones that control other endocrine glands.
What is the roll of neurosecretory cells in regulating the release of hormones from the anterior pituitary gland?
Release and inhibit hormones in their cell bodies and package the hormones inside vesicles, which reach the axon terminals by axonal transport. They then undergo exocytosis. This prevents the hormones from being diluted or destroyed.
What is the function of OXYTOXIN?
A positive feedback system. Enhances smooth muscle contractions in the uterine wall to facilitate labor and delivery, and stimulates milk ejection from mammary glands after delivery.
What is the function of ADH? (Antidiuretic hormone)
Causes the kidneys to return more water to the blood while decreasing urine volume. Blood osmotic pressure and blood volume affect secretion of ADH.
What is the importance of iodide in terms of the thyroid hormones?
The hormones are synthesised from both iodide and tyrosine.
What are the functions of calcitonin?
Lowers the blood levels of calcium ions.
What are the functions of parathyroid hormones?
Regulates blood levels of calcium, magnesium and phosphate ions.
What is meant by permissive hormones?
When it needs exposure to a second hormone to exert its full effect.
What is meant by synergistic hormone?
When more than one hormone produce the same affect and when combined the effects are imperative.
What is meant by antagonistic hormones?
When the action of one hormone opposes the action of a second hormone.
