Chapter Questions The Endocrine System
For each of the following statements indicate whether it applies more to the endocrine system or the nervous system.
•discrete responses =
•controls growth and development =
•long-lasting responses =
•rapid = nervous system
•discrete responses = nervous system
•controls growth and development = endocrine system
•long-lasting responses = endocrine system
What two endocrine glands are found in the neck?
The thyroid and parathyroid are both found in the neck.
What is the difference between a hormone and a paracrine?
Hormones are long-distance chemical signals that travel in blood or lymph throughout the body. Paracrine are short-distance chemical signals.
Name the two major chemical classes of hormones. Which class consists entirely of lipid-soluble hormones? Name the only hormone in the other chemical class that is lipid soluble.
The two major chemical classes of hormones are amino acid based and steroids. Steroids consist entirely of lipid-soluble hormones. Thyroid hormones are the only amino acid based hormones that are lipid-soluble.
Consider the signaling mechanisms of water-soluble and lipid-soluble hormones, in each case where are the receptors found and what is the final outcome?
Water-soluble hormones act on receptors in the plasma membrane. These receptors are usually coupled via regulatory molecules called G proteins to one or more intracellular second messengers which mediate the target cell response.
Lipid-soluble hormones act on receptors inside the cell, which directly activates genes and stimulating synthesis of specific proteins
What are the three types of stimuli that control hormone release?
Hormone release can be triggered by humoral, neural, or hormonal stimuli.
What is the key difference between the way the hypothalamus communicates with the anterior pituitary and the way it communicates with the posterior pituitary?
The hypothalamus communicates with the anterior pituitary via hormones released into a special portal system of blood vessels. In contrast, it communicates with the posterior pituitary via action potentials traveling down axons that connect the hypothalamus to the posterior pituitary.
Anita drank too much alcohol one night and suffered from a headache and nausea the next morning. What caused these “hangover” effects?
Drinking alcoholic beverages inhibits ADH secretion and causes copious urine output. The dry mouth and intense thirst of a hangover reflects this dehydrating effect.
List the four anterior pituitary hormones that are tropic hormones and name their target glands.
• Thyroid stimulating hormone (TSH)– stimulates thyroid gland to release thyroid hormone.
• Adrenocorticotropic hormone (ACTH) – promotes the release of glucocorticoids and androgens (mineralocorticoids to a lesser extent) target Adrenal cortex
• Follicle-stimulating hormone (FSH) – In females stimulates ovarian follicle maturation and estrogen production, in males stimulates sperm production. Targets ovaries and testes.
• Lueinizing hormone (LH) - in females triggers ovulation and stimulates ovarian production of estrogen and progesterone, in males promotes testosterone production. Targets ovaries and testes.
What is the major effect of thyroid hormone? Parathyroid hormone? Calcitonin?
• Thyroid hormone increases basal metabolic rate in the body.
• Parathyroid hormone increases blood calcium levels in a variety of ways.
• Calcitonin at high levels has a calcium lowering, bone sparing effect
Name the cells that release each of the three hormones listed above.
• Thyroid follicle cells release thyroid hormone.
• Parathyroid cells release parathyroid hormone.
• Parafollicular cells (C cells) in the thyroid gland release calcitonin.
List the three classes of hormones released from the adrenal cortex and for each briefly state its major effects
• mineralcorticoid – aldosterone, steroid hormone that regulates the excretion of salt, potassium, and water.
• Glucocorticoid – cortisol, steroid hormone that affects fat, carbohydrate, and protein levels in the blood as well as regulating the immune response.
• Gonadocorticoid – androgens, steroid that converts to testosterone of estrogen after release. Contributes to female libido, produces pubic and axillary hair, also a source of estrogen after menopause.
Synthetic melatonin supplements are available, although their safety and efficacy have not been proved. What do you think they might be used for?
You've just attended a football game with your friend, Sharon, who is diabetic. While Sharon drank only one beer during the game, she is having trouble walking straight, her speech is slurred, and she is not making sense.
What does it mean when we say Sharon is diabetic?
What is the most likely explanation for Sharon's current behavior?
How could you help her?
When we say Sharon is diabetic, this means that she has insufficient insulin action in her body.
The most likely explantion for Sharon's behavior is that she has taken too much insulin and is experiencing hypoglycemia.
You could help her by making sure she immediately ingest a sugary snack or drink.
Diabetes mellitus and diabetes insipidus are both due to lack of a hormone. Which hormone causes which? What symptom do they have in common? What would you find in the urine of a patient with one but not the other?
Diabetes mellitus is due to a lack of insulin production or action, whereas diabetes insipidus is due to a lack of insulin production or action, whereas, diabetes insipidus is due to a lack of ADH. Both conditions are characterized by production of copious amounts of urine. You would find glucose in the urine of a patient with diabetes mellitus, but not in the urine of a patient with diabetes insipidus.
Which of the two chemical classes of hormones introduced at the beginning of this chapter do the gonadal hormones belong to? Which major endocrine gland secretes hormone of this same chemical class?
The gonadal hormones are steroid hormones. A major endocrine gland that also secretes steroid hormones is the adrenal cortex.
Which hormone does the heart produce and what is its function?
The heart produces atrial natriuretc peptide (ANP). ANP decreases blood volume and blood pressure by increasing the kidneys' production of salty urine.
What is the function of the hormone produced by the skin?
Vitamin D3, produced in inactive form by the skin, increases intestinal absorption of calcium.
In the elderly, the decline in levels of which hormone is associated with muscle atrophy? With osteoporosis in women?
The decline in growth hormone with age contributes to muscle atrophy.
The decline in estrogen contributes to osteoporosis in women.