BIOL 2302 EXAM

Which of the following adrenergic receptors increase cAMP levels?

B receptors (beta) Yes, these receptors are coupled to adenylate cyclase by Gs receptors that increase cAMP.

What is a megakaryocyte? What does its name mean?

A megakaryocyte is a cell that produces platelets. Its name means "big nucleus cell."

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 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.

Down-regulation involves the loss of receptors and prevents the target cells from overreacting to persistently high hormone levels.

true

Growth factor hormones, such as insulin, bind to which type of receptor?

tyrosine kinase receptors Yes, insulin binds to tyrosine kinase receptors and works without a second messenger.

What type of hormones bind to receptors located on the cell membrane?

water-soluble hormones, such as insulin and epinephrine Yes, peptides and catecholamines are water-soluble hormones that cannot diffuse through the plasma membrane.

Any given hormone will influence the activity of __________.

its target cells

What are the three types of stimuli that control hormone release?

Hormone release can be triggered by humoral, neural, or hormonal stimuli.

A liver cell responds to insulin by

Taking in glucose and converting it to glycogen.

Which of the following is NOT a purely endocrine organ?

kidney

In which of the following mechanisms of hormone action do intracellular calcium ions act as a final mediator?

PIP2-calcium signaling mechanism

Identify cells a-e below. Match each cell to a statement. (Cells may be used more than once.)

(1) Neutrophils (e) are and monocytes (c) become important phagocytes. (2) Eosinophils (b), basophils (d), and neutrophils (e) are granulocytes. (3) Lymphocytes (a) are abundant in lymph nodes and in the spleen. (4) The granule contents of basophils (d) are similar to those of mast cells.

List the four anterior pituitary hormones that are tropic hormones and name their target glands.

LH and FSH are tropic hormones that act on the gonads, TSH is a tropic hormone that acts on the thyroid, and ACTH is a tropic hormone that acts on the adrenal cortex. (If you said growth hormone, that's also a good answer, as GH causing the liver to release IGFs might also be considered a tropic effect.)

Which type of hormone generally stays in the blood longer following its secretion, lipid soluble or water soluble?

Lipid-soluble hormones have longer half-lives, meaning that they stay in the blood longer. (They are not as readily excreted by the kidneys because they are bound to plasma proteins, and most need to be metabolized by the liver before they can be excreted.)

Body cells that respond to insulin include

Liver cells, as well as most other cells of the body.

Synthetic melatonin supplements are available, although their efficacy and long-term safety have not been proved. What do you think they might be used for?

Melatonin is used by some individuals as a sleep aid, particularly to counter jet lag.

Because of the blood brain barrier, brain tissue is somewhat less accessible to circulating macrophages. Because of this, one type of CNS cell, can become phagocytic. Which type of cell is this?

Microglial cells can become phagocytes in the brain.

What is the difference between T3 and T4? Which one of these is referred to as thyroxine?

T4 has four bound iodine atoms, and T3 has three. T4 is the major hormone secreted, but T3 is more potent. T4 is referred to as thyroxine.

Nigel is told he has type A blood. Which ABO antibodies does he have in his plasma? Which agglutinogens are on his RBCs? Could he donate blood to an AB recipient? Could he receive blood from an AB donor? Explain.

Nigel has anti-B antibodies in his blood and type A agglutinogens (antigens) on his RBCs. He can donate blood to an AB recipient, but he should not receive blood from an AB donor because his anti-B antibodies will cause a transfusion reaction.

What is the major effect of thyroid hormone? Parathyroid hormone? Calcitonin?

Thyroid hormone increases basal metabolic rate (and heat production) in the body. Parathyroid hormone increases blood Ca2+ levels in a variety of ways. Calcitonin at high (pharmacological) levels has a Ca2+-lowering, bone-sparing effect. (At normal blood levels its effects in humans are negligible.)

Why does TH require plasma proteins in order to move through blood? Where are the receptors for TSH located?

Thyroid hormone must be carried through blood by plasma proteins because it is lipid soluble and so does not readily dissolve in blood, which is mostly water. The receptors for TSH (thyroid-stimulating hormone) are located on the plasma membrane of the thyroid follicular cells (on the sides facing away from the colloid). (Recall that TSH is a water-soluble hormone from the anterior pituitary.)

Athletes can use industry-produced EPO as a performance-enhancing drug to increase the effects of their naturally-produced EPO. These athletes will experience ______.

decreased production of EPO by their kidneys EPO (erythropoietin) is a powerful hormone secreted by the kidney. Its synthesis is activated by renal tissue hypoxia and inhibited by normal tissue oxygenation.

The anterior pituitary is known as the "master endocrine gland" because it controls the hypothalamus.

false

Which of the following hormones stimulates gamete (sperm or egg) production?

follicle-stimulating hormone

Which of the following stimulate(s) most body cells to increase in size and divide?

growth hormone

Endocrinology involves the study of the endocrine organs and ______________.

hormones

Which of the following conditions, if left untreated, progresses to respiratory paralysis and death?

hypoparathyroidism Hypoparathyroidism, or PTH deficiency, most often follows parathyroid gland trauma or removal during thyroid surgery. However, an extended deficiency of dietary magnesium (required for PTH secretion) can cause functional hypoparathyroidism. The resulting hypocalcemia increases the excitability of neurons and accounts for the classical symptoms of tetany, such as loss of sensation, muscle twitches, and convulsions. Untreated, the symptoms progress to respiratory paralysis and death.

One can predict that a person with uncontrolled diabetes mellitus would probably have ______.

increased secretion of ANP (atrial natiuretic peptide) increased secretion of ADH (anti-diuretic hormone) excessive thirst *All of the listed responses are correct* Using your textbook, review the cardinal signs of diabetes mellitus and the ways in which the body attempts to compensate for insulin deficit.

Adrenocortical androgens are normally converted in females into estrogens. However, in adrenogenital syndrome, females develop a beard and a masculine pattern of body hair distribution; this occurs due to ______.

insufficient level of enzymes that convert androgens into estrogens During the end steps of sex hormone, synthesis androstendione is converted into either testosterone or estrogen. If the body lacks the enzyme to convert androstendione to estrogen, the remaining pathway to testosterone will predominate.

What cells in the body respond to glucagon by breaking down glycogen and releasing glucose?

liver cells

In a cancer patient undergoing chemotherapy, the decision to utilize a CSF capable of specifically stimulating the production of only the granular leukocytes would require that the CSF acts exclusively on ______.

myeloblasts Myeloblasts are the precursor cells that ultimately form basophils, eosinophils, and neutrophils.

As blood levels of __________ rise, the expulsive contractions of labor gain momentum and finally end in birth.

oxytocin

The cells found within the parathyroid glands that secrete parathyroid hormone are called __________.

parathyroid cells

Which of the following is NOT one of the three major types of stimuli to trigger endocrine glands to manufacture and release their hormones?

permissive stimuli

Which intracellular substance degrades cAMP, thus inactivating the response to a hormone?

phosphodiesterase Yes, phosphodiesterase is an intracellular enzyme that degrades cAMP.

Which of the following homeostatic imbalances results from hyposecretion of growth hormone?

pituitary dwarfism

Which of the following occurs within a negative feedback system?

target organs effects inhibit further hormone release

Which hormone's receptor is always bound to DNA, even when the receptor is empty?

thyroid hormone Yes, thyroid hormones are lipid soluble and their receptors are bound to the response elements of the DNA.

The body's tendency to maintain relatively constant internal conditions is called

homeostasis

When blood glucose levels are low

The pancreas releases glucagon, which eventually causes blood glucose levels to increase.

When blood glucose levels are high

The pancreas releases insulin. The pancreas responds to high blood glucose levels by releasing insulin.

What are the three steps of hemostasis?

The three steps of hemostasis are vascular spasm, platelet plug formation, and coagulation.

Autocrines are long-distance chemical signals that travel in blood throughout the body.

false

What keeps intracellular receptors from binding to DNA before a hormone binds to the receptor?

chaperone proteins (chaperonins) Yes, each receptor has two binding sites. The chaperone protein blocks the DNA binding site until a hormone binds at the hormone binding site.

Steroid hormones are synthesized from __________.

cholesterol

Which of the following hormones has intracellular receptors?

cortisol Yes, cortisol is one of the lipid-soluble steroid hormones. Thyroid hormones are also lipid soluble.

Which of the following homeostatic imbalances usually results from deficits in both glucocorticoids and mineralocorticoids?

Addison's disease

Amos has leukemia. Even though his WBC count is abnormally high, Amos is prone to severe infections, bleeding, and anemia. Explain.

Amos's red bone marrow is spewing out many abnormal white blood cells, which are crowding out the production of normal bone marrow elements. The lack of normal white blood cells allows the infections, the low number of platelets fails to stop bleeding, and the lack of erythrocytes is anemia.

List two protective functions of blood.

Blood can prevent blood loss by forming clots when a blood vessel is damaged. Blood can prevent infection because it contains antimicrobial proteins and white blood cells.

Where in the cell are steroid hormones synthesized? Where are peptide hormones synthesized? Which of these two types of hormone could be stored in vesicles and released by exocytosis?

Steroid hormones are synthesized on the membrane of the smooth endoplasmic reticulum. Peptide hormones are synthesized on rough endoplasmic reticulum. Peptide hormones can be stored in vesicles and released by exocytosis.

Which class of hormones consists entirely of lipid-soluble hormones? Name the only hormone in the other chemical class that is lipid soluble.

Steroids are all lipid soluble. Thyroid hormones are the only amino acid-based hormones that are lipid soluble.

Zoe 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 from the posterior pituitary and causes copious urine output and dehydration. The dehydration causes the hangover effects.

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.

How many molecules of oxygen can each hemoglobin molecule transport? What part of the hemoglobin binds the oxygen?

Each hemoglobin molecule can transport four O2. The heme portion of the hemoglobin binds the O2.

Which gland below is an endocrine gland and which is an exocrine gland? How can you tell?

Gland (a) is an exocrine gland and gland (b) is an endocrine gland. In gland (a), you can see the duct that is characteristic of exocrine glands. The duct conveys glandular secretions either out of the body onto the skin or into a hollow organ. Endocrine glands, on the other hand, do not have ducts and instead secrete hormones into the blood. Notice the prominent blood vessels around gland (b).

List the three classes of hormones released from the adrenal cortex and briefly state the major effect(s) of each.

Glucocorticoids are stress hormones that, among many effects, increase blood glucose. Mineralocorticoids increase blood Na+ (and blood pressure) and decrease blood K+. Gonadocorticoids are male and female sex hormones that are thought to have a variety of effects (for example, contribute to onset of puberty, sex drive in women, pubic and axillary hair development in women).

Which of the following is NOT one of the areas in which thyroid hormone (TH) plays an important role?

Helping the body avoid dehydration and water overload

What is the difference between a hormone and a paracrine?

Hormones are released into the blood and transported throughout the body, whereas paracrines act locally, generally within the same tissue.

Which second messenger causes the release of calcium from the endoplasmic reticulum?

IP3 Yes, inositol trisphosphate releases calcium from intracellular storage sites.

Emily Wong, 17, is brought to the ER with a fever, headache, and stiff neck. You suspect bacterial meningitis. Would you expect to see an elevated neutrophil count in a differential WBC count? Explain.

If Emily has a bacterial meningitis, a differential WBC count would likely reveal an increase in neutrophils because neutrophils are a major body defense against bacteria.

Suppose you are caring for a patient in liver failure due to chronic alcoholism. What problems would you expect the reduced synthesis of plasma proteins to cause in this patient?

Plasma proteins perform many key functions in the blood (see Table 17.1). One key function is to maintain the correct osmotic pressure in the blood. Without the osmotic pressure of plasma proteins "pulling" water molecules into the bloodstream, more water enters the tissues. Your patient may have tissue swelling (called edema) due to water leaking out of the blood. In addition, some of the plasma proteins synthesized by the liver (e.g., fibrinogen) are clotting proteins, so your patient may bleed more readily in response to only minor injuries. While you might expect to see problems due to the loss of the carrier function of many plasma proteins, this doesn't generally lead to easily observable signs and symptoms.

Name the enzyme that catalyzes each of the steps in the final common pathway shown in (a) and (b) below. What is the key difference between prothrombin and thrombin? Between fibrinogen and fibrin? Between most factors before and after they are activated?

Prothrombin activator catalyzes the conversion of prothrombin to thrombin. Thrombin catalyzes the conversion of fibrinogen to fibrin. Prothrombin is an inactive precursor, whereas thrombin acts as an enzyme. Fibrinogen is water soluble, whereas fibrin is not. Most factors are inactive in blood before activation and become enzymes upon activation. (There are exceptions, such as fibrinogen and calcium.)

Which part of the gland(s) below releases steroid hormones? Amino acid-based hormones? Name the hormone released from (c) that acts on (a). Histologically, what do (b) and (d) have in common that differentiates them from other glands?

The adrenal cortex (a) releases steroid hormones. The adrenal medulla (b) and anterior pituitary (c) and posterior pituitary (d) all release amino acid-based hormones. ACTH from the anterior pituitary acts to cause release of steroid hormones from the adrenal cortex. Both the adrenal medulla (b) and posterior pituitary (d) are composed of nervous tissue rather than the glandular tissue (a type of epithelial tissue) that other glands are made of.

For each of the following statements, indicate whether it applies more to the endocrine system or the nervous system: rapid; discrete responses; controls growth and development; long-lasting responses.

The endocrine system is more closely associated with growth and development, and its responses tend to be long-lasting, whereas nervous system responses tend to be rapid and discrete.

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 hormones 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 natriuretic peptide (ANP). ANP decreases blood volume and blood pressure by increasing the kidneys' production of salty urine.

What is the hematocrit? What is its normal value?

The hematocrit is the percentage of blood that is occupied by erythrocytes. It is normally about 45%.

Patients with advanced kidney disease often have anemia. Explain the connection.

The kidneys' synthesis of erythropoietin is compromised in advanced kidney disease, so RBC production decreases, causing anemia.

What is the main function of the hormone produced by the skin?

The major function of vitamin D3, produced in inactive form by the skin, is to increase intestinal absorption of calcium.

Which two endocrine glands are found in the neck?

The thyroid and parathyroid glands are found in the neck.

What are the two major stimuli for aldosterone release? What is the major stimulus for cortisol release?

The two major stimuli for aldosterone release are (1) a decrease in blood volume or blood pressure, which triggers the renin-angiotensin-aldosterone mechanism, and (2) an increase in plasma K+ levels. The major stimulus for cortisol secretion is ACTH from the anterior pituitary. ACTH release, in turn, is controlled by CRH from the hypothalamus. CRH release follows a diurnal (day-night) rhythm and is increased in response to various stressors, as well as by hypoglycemia and fever.

Which bleeding disorder results from not having enough platelets? From absence of clotting factor VIII?

Thrombocytopenia (platelet deficiency) results in failure to plug the countless small tears in blood vessels, and so manifests as small purple spots (petechiae). Hemophilia A results from the absence of clotting factor VIII.

Name the cells that release each of the three hormones listed above.

Thyroid follicular cells release thyroid hormone, parathyroid cells in the parathyroid gland release parathyroid hormone, and parafollicular (C) cells in the thyroid gland release calcitonin.

Which is the correct order of events for hormones activating Gs proteins?

activation of G protein, binding of GTP, activation of adenylate cyclase, conversion of ATP to cAMP Yes, Gs proteins are stimulatory proteins that activate cAMP.

What is the mechanism of action of lipid-soluble hormones?

activation of genes, which increases protein synthesis in the cell Yes, lipid-soluble hormones diffuse into the nucleus or they diffuse into the cytoplasm and then move into the nucleus, where they affect transcription and translation.

After a lipid-soluble hormone is bound to its intracellular receptor, what does the hormone complex do?

acts as a transcription factor and binds to DNA, activating a gene Yes, then mRNA is synthesized.

When one hormone opposes the action of another hormone, the interaction is called __________.

antagonism

During erythroblastosis fetalis, a Rh− mother's anti-Rh antibodies that have crossed the placenta will cause agglutination of the fetus's Rh+ RBCs. However, the reverse problem never happens when a Rh+ mother is pregnant with a Rh− fetus; that is, antibodies produced by the fetus cannot cause agglutination of the mother's Rh+ RBCs. This is true because ______.

antibodies that can cause this agglutination are not produced by a fetus The (+) in Rh+ indicates that the red blood cells of the fetus have this agglutinin (antigen) on their surface. Therefore, they don't produce antibodies to that surface protein. If the fetus made these antibodies, agglutination would occur in their own (fetal) blood.