Endocrine system Chapter 11

Which of the following is both an endocrine and exocrine gland? 1)Liver 2)Thyroid Gland 3)Adrenal Glands 4)Parathyroid Glands

#1 -Endocrine glands are ductless glands whose hormones end up in the blood stream. -Exocrine glands secrete products into ducts. -The LIVER secretes bile into a duct that eventually travels to the duodenum to emulsify fats. It also carries out the ductless secretion of hormones, chief among them insulin-like growth factor, into the bloodstream.

All of the following are true of posterior pituitary hormones EXCEPT: They include direct and tropic hormones They are released from the posterior pituitary A nerve signal from the hypothalamus stimulates their release They include antidiuretic hormone and oxytocin

#1 These hormones do NOT include the direct and tropic FLAT PEG hormones, which are synthesized by the anterior pituitary.

Unlike polypeptide hormones, steroid hormones: Demonstrate rapid onset of effect Are more likely to have an associated receptor in the cytosol or nucleus More commonly function via specific second messengers Are more rapidly degraded and therefore demonstrate more temporary effects

#2 Because steroid hormones are lipophilic, they are able to cross the lipid membrane and function in the cytosol or nucleus.

Biosynthesis of steroids begins with: Methylation of a sesquiterpene Binding of pyrophosphate to a terpene Generation of a sterol Binding of two terpene groups

#2 The biosynthesis of steroids begins with adding a pyrophosphate to a terpene.

Each hormone's organ specificity is determined by: Whether it is a corticosteroid or a gonadotropic hormone Its ability to interact with a specific receptor The signaling cascade it initiates Whether it is lipophilic or lipophobic

#2 The hormone's ability to interact with a specific receptor on a particular cell type determines its effect on that cell or organ system.

Antibodies directed against pancreatic cells result in these cells' destruction. What laboratory abnormality might be seen in this scenario? Depressed serum calcium Elevated serum glucose Depressed serum sodium Elevated serum calcium

#2 Therefore in this condition, glucose metabolism is affected. In Type I diabetes, SERUM GLUCOSE is elevated.

Hormones secreted by the hypothalamus would be classified as: Intracrine Autocrine Paracrine Endocrine

#3 -Paracrine signaling, in contrast, means that the hormone acts on a nearby, but different, organ. Remember that the hypothalamic hormones primarily act on the pituitary. Therefore this should be classified as paracrine signaling.

After consuming a banana split, which hormones would be expected to increase? 1)Parathyroid Hormone 2)Glucagon 3)Insulin 4)Prolactin

#3 -When eating food, our digestive system breaks down the food into macromolecules such as proteins, lipids, and carbohydrates. -Hormones that help our body take up these biological molecules would be released after a meal. -Insulin lowers blood glucose concentration by increasing cell permeability to glucose and amino acids.

The role of adenylate cyclase is: To degrade steroid hormones, terminating their function To activate G protein-coupled receptors via phosphorylation To aid in signal amplification via conversion of GTP to GDP To cyclize ATP in order to generate second messengers

#4 Adenylate cyclase aids in conversion of ATP to cAMP, which acts as a second messenger.

Steroid hormones include which of the following: Thyroid hormones and adrenal cortical hormones Pancreatic and thyroid hormones Sex hormones and adrenal medullary hormones Sex hormones and adrenal cortical hormones

#4 Adrenal corticosteroids are mineralocorticoids, a type of steroid hormone.

The concentration of hormones in the bloodstream is regulated by: Production of receptor antagonists Indirect growth-promoting effects Nutritional signals to the endocrine gland Positive and negative feedback loops

#4 Direct feedback loops let various glands know when to stop producing hormones. For example, sufficient thyroid hormone in the bloodstream will alert the pituitary gland to cease producing thyroid-stimulating hormone.

Which of the following is a physiological function that is mediated by a hormone released by the posterior pituitary? Maturation of the egg and sperm Increase in thyroid hormone level Water retention Decrease in calcium levels

-Antidiuretic Hormone (ADH) causes the collecting duct of the kidney to become more permeable to water and therefore assists in WATER RETENTION making it the correct choice. -The posterior pituitary releases two hormones: ADH and Oxytocin. -Oxytocin regulates uterine contractions during pregnancy and breast-feeding.

The primary role of the parathyroid gland is: To maintain metabolic homeostasis To regulate serum calcium levels To send hormonal signals to other endocrine organs To receive hormonal signals from the hypothalamus

Rather than metabolic homeostasis, the parathyroid is involved in calcium homeostasis. -The pituitary, not the parathyroid, receives hormonal signals from the hypothalamus. -The parathyroid gland does not send signals directly to other endocrine organs.

Which of the following hormones would bind to receptors located on the inside of a cell? Prolactin Follicle-Stimulating Hormone Growth Hormone Testosterone

Testosterone is a steroid hormone, therefore it will diffuse through the membrane and bind to cytoplasmic or nuclear receptors that will allow it to act as a transcription factor and ultimately alter gene expression of the cell. -Hormones that are derived from amino acids are hydrophilic whereas hormones derived from cholesterol are hydrophobic -Steroid hormones that are derived from cholesterol are hydrophobic and diffuse through the membrane into the cell.

Which hormone increases basal metabolic rate in the body?

Thyroid hormone -increases the basal metabolic rate, affects protein synthesis, and helps regulate long bone growth. Just remember that thyroid hormones help regulate metabolism throughout the body.

Hormones travel through the blood stream and bind to receptors located on target cells. Which of the following would NOT bind to transmembrane proteins on the target cells? Antidiuretic Hormone Estrogen Insulin Prolactin

-Estrogen is a hydrophobic steroid hormone and readily diffuses across the cell membrane and binds to receptors located inside the cell. It does not bind to transmembrane proteins located on the surface of the cell and is the correct answer. -Peptide hormones, with the exception of tyrosine, are generally hydrophilic. -Hydrophilic molecules do not have favorable interactions with the hydrophobic fatty acid tails within the phospholipid bilayer and therefore do not readily diffuse across the membrane.

Which of the following hormones would be expected to increase if you were studying all day for a test and skipped breakfast and lunch? Insulin Glucagon Calcitonin Growth Hormone

-Glucagon converts stored glycogen into glucose that is then released into the bloodstream when your blood sugar levels are low. Insulin has the opposite effect and lowers blood glucose concentration in the blood by allowing tissues to absorb glucose. -After skipping meals, you would be low on biological molecules needed for metabolic processes e.g. carbohydrates. -Therefore, your body would have to make up for this lack of carbohydrates from its stored glycogen in the liver.

Growth factors and histamine are chemical agents released in small amounts that act locally on neighboring cells. Which of the following best describes the function of growth factors and histamine? Endocrine function Autocrine function Paracrine function None of the above

-Growth factors and histamine have a paracrine function. Locally suggests that these growth factors and histamines act on neighboring cells that are close by. Endocrine hormones get around the body by being released into the bloodstream and binding to receptors on target cells that may be far away from where the signal was released. Autocrine hormones act on the cells that release them.

Which of the following accurately describes thyroid hormone? Binds to receptors on the outside of the cell Binds to receptors on the inside of the cell Released from the anterior pituitary Derived from cholesterol

-Thyroid hormone is an exception. Even though it is derived from the amino acid tyrosine, it is lipid soluble and diffuses across the cell membrane and will bind to receptors inside the cell. Thyroid hormone acts like a steroid. -In general, steroid hormones readily diffuse across the cell membrane and peptide/amine hormones are hydrophilic and bind to cell receptors on the surface. -Thyroid hormone is derived from the amino acid tyrosine.