Questions and Answers
Which type of hormone is lipid soluble?
Which molecules determine the tissue specificity of hormones?
Receptors
Lipid-insoluble hormones affect their target cells by binding to receptors inside the cell.
False
Which of the following statements about lipid-soluble hormones is true?
Signup and view all the answers
Which of the following is a structure that allows hormone-receptor complexes to bind to specific DNA sequences?
Signup and view all the answers
What is the role of cAMP in the signal transduction pathway activated by epinephrine?
Signup and view all the answers
For a signal transduction pathway to be activated, hormones must be present in the bloodstream at very high concentrations.
Signup and view all the answers
Receptors for nonsteroid hormones are located in _____
Signup and view all the answers
Which of these is a nonsteroid hormone?
Signup and view all the answers
How do nonsteroid hormones differ from steroid hormones?
Signup and view all the answers
Which of these extracellular signal molecules could diffuse through a plasma membrane and bind to an intracellular receptor?
Signup and view all the answers
The primary reason steroid hormones usually act slowly is that _____
Signup and view all the answers
Steroid hormone-receptor complexes act in _____
Signup and view all the answers
The hormone epinephrine causes opposite effects in two populations of target cells because _____
Signup and view all the answers
Among insects, the metamorphic transition from pupal form to adult form is associated with _____
Signup and view all the answers
In their mechanism of action, a difference between lipid-soluble and water-soluble hormones is that _____
Signup and view all the answers
Oxytocin secretion and milk release from the mammary glands of lactating female mammals are initiated by _____
Signup and view all the answers
The counter-regulatory functions of the pancreas refer to the fact that it _____
Signup and view all the answers
This disorder typically arises prior to puberty and is generally treated by injections of the hormone missing from the affected individual's bloodstream.
Signup and view all the answers
What is the function of endocrine glands?
Signup and view all the answers
The homeostatic system for blood calcium concentration is maintained by the hormones calcitonin and parathyroid hormone.
Signup and view all the answers
Which of the following statements about the pituitary gland is false? Neurosecretory cells produce hormones that are stored in the anterior pituitary.
Signup and view all the answers
The pancreas is responsible for producing hormones that maintain the homeostatic levels of glucose in the blood.
Signup and view all the answers
How is the production of hormones such as thyroxine and estrogen regulated?
Signup and view all the answers
What is true about endocrine glands and the hormones they produce?
Signup and view all the answers
Gigantism, a condition characterized by exceptionally rapid growth, is sometimes caused by a tumor that induces the gland in which it develops to overproduce a certain hormone. Where would such a tumor be expected to grow?
Signup and view all the answers
Which of these glands secretes releasing hormones?
Signup and view all the answers
Which of these hormones are responsible for the 'fight or flight' response to danger?
Signup and view all the answers
Adrenocorticotropic hormone (ACTH) triggers the release of _____ in response to stress.
Signup and view all the answers
_____ are the main male hormones.
Signup and view all the answers
What hormone promotes water retention by the kidneys?
Signup and view all the answers
Which hormone opposes the action of parathyroid hormone?
Signup and view all the answers
Which hormone stimulates hormone production by the ovaries and testes?
Signup and view all the answers
Which hormone stimulates milk production?
Signup and view all the answers
Steroid and peptide hormones typically have in common?
Signup and view all the answers
Shortly after ingesting a big plate of carbohydrate-rich pasta, what results would you expect in blood hormone levels?
Signup and view all the answers
Study Notes
Hormones and Their Characteristics
- Steroids are lipid-soluble hormones that can easily cross cell membranes.
- Tissue specificity of hormones is determined by receptors found in target tissues.
- Lipid-insoluble hormones bind to receptors on the cell surface and utilize signal transduction pathways, while lipid-soluble hormones influence gene transcription directly.
- Zinc fingers are DNA-binding domains on some hormone receptors, allowing hormone-receptor complexes to bind to specific DNA sequences.
Mechanisms of Action
- Cyclic AMP (cAMP) activates protein kinase A, which phosphorylates enzymes in the signal transduction pathway, playing a crucial role in hormonal responses.
- Hormones can activate pathways effectively at low concentrations, amplifying their effects through second messengers.
- Nonsteroid hormones act via signal transduction mechanisms, whereas steroid hormones directly affect transcription in the nucleus.
- Estrogen can diffuse through a plasma membrane to bind with an intracellular receptor, unlike most nonsteroid hormones.
Physiological Effects of Hormones
- Steroid hormones take longer to exert effects due to changes in gene expression requiring time to manifest.
- Oxytocin release during breastfeeding is triggered by the baby's sucking, demonstrating a neuroendocrine pathway.
- The pancreas releases insulin and glucagon to maintain glucose levels, exhibiting counter-regulatory functions.
Endocrine System and Homeostasis
- Endocrine glands release hormones into circulation, influencing processes like glucose regulation and calcium homeostasis (calcitonin and parathyroid hormone).
- The pituitary gland, particularly its anterior portion, produces various hormones; neurosecretory cells work in the posterior pituitary.
- Hormone production, such as that of thyroxine and estrogen, is regulated by the hypothalamus through the anterior pituitary gland.
- The adrenal cortex releases glucocorticoids in response to ACTH during stress.
Hormonal Disorders and Regulation
- Type I diabetes mellitus results from inadequate insulin secretion due to pancreatic dysfunction, often treated with insulin injections.
- Gigantism is linked to tumors in the pituitary gland causing excessive growth hormone production.
- Releasing hormones are secreted by the hypothalamus, playing a vital role in regulating the endocrine system.
Key Hormones and Their Functions
- Antidiuretic hormone (ADH) promotes kidney water retention.
- Calcitonin opposes parathyroid hormone, lowering blood calcium levels.
- Luteinizing hormone (LH) stimulates hormone production in the ovaries and testes.
- Prolactin encourages milk production in lactating mammals.
Hormonal Responses and Effects
- Following carbohydrate-rich meals, insulin levels increase while glucagon levels decrease, facilitating glucose uptake.
- Epinephrine and norepinephrine are critical for activating the "fight or flight" response, eliciting various physiological changes.
- Hormonal responses vary in target cells based on specific receptor-transduction mechanisms, exemplified by the differing effects of epinephrine on vasodilation and vasoconstriction.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge of hormones and their mechanisms with these flashcards from Biology Chapter 45. Explore lipid-soluble and lipid-insoluble hormones, as well as the role of receptors in hormone action. Perfect for quick revisions or study sessions!
