Lesson 3: Endocrine Glands Flashcards
How does the endocrine system differ from the nervous system in communication?
The endocrine system uses chemical signals (hormones) via the bloodstream, while the nervous system uses electrical impulses for rapid communication.
What are the two feedback mechanisms that regulate hormone levels?
Negative feedback (inhibits further secretion) and positive feedback (enhances secretion).
What is an example of positive feedback in the endocrine system?
Oxytocin release during childbirth to enhance uterine contractions.
What is an example of negative feedback in the endocrine system?
Regulation of blood glucose by insulin and glucagon.
What are amine hormones derived from?
Amino acids such as tyrosine (e.g., epinephrine, T3, T4).
What are peptide hormones composed of?
Chains of amino acids (e.g., insulin, glucagon).
What are the precursors of steroid hormones?
Cholesterol.
How do lipid-soluble hormones (e.g., steroid hormones) affect target cells?
They cross the plasma membrane and bind to intracellular receptors to regulate gene expression.
How do water-soluble hormones affect target cells?
By binding to surface receptors and initiating second messenger pathways.
What are enteroendocrine cells?
Cells in the GI tract that release hormones like gastrin and secretin.
What hormone secreted by the stomach stimulates gastric acid production?
Gastrin.
What hormone secreted by the duodenum stimulates the pancreas to release bicarbonate?
Secretin.
What is the role of cholecystokinin (CCK)?
It stimulates secretion of pancreatic enzymes and the release of bile from the gallbladder and pancreatic enzymes.
What is the function of ghrelin?
To stimulate hunger.
What regulates the anterior pituitary?
Releasing and inhibiting hormones from the hypothalamus.
What is the target of thyroid-stimulating hormone (TSH)?
The thyroid gland.
What is the function of adrenocorticotropic hormone (ACTH)?
To stimulate the adrenal cortex to release cortisol.
What does prolactin regulate?
Milk production in mammary glands.
What hormones are transported along the hypothalamic-hypophyseal tract to the posterior pituitary?
Oxytocin and antidiuretic hormone (ADH).
Oxytocin and antidiuretic hormone (ADH).
To conserve water by reducing urine output.
What is the primary effect of growth hormone (GH)?
Stimulates growth and metabolism in tissues, particularly bone and muscle.
What condition results from excess growth hormone after puberty?
Acromegaly.
What is diabetes insipidus?
A condition caused by insufficient ADH, leading to excessive urine production.
What is the role of iodide in thyroid hormone synthesis?
It is essential for the production of T3 and T4.