Ch. 13-Prep for Exam

For each description, indicate the correct pancreatic hormone.

Insulin- Promotes the formation of glycogen from glucose Glucagon- Stimulates liver to breakdown glycogen Glucagon- Stimulates the breakdown of fats Insulin- Decreases blood glucose levels Glucagon- Raises blood glucose levels Insulin- Secreted by beta cells Glucagon- Secreted by alpha cells Insulin- Enhances synthesis of proteins

The pancreatic hormones function together to stabilize blood glucose concentration through a negative feedback mechanism. The pancreatic hormone __________ lowers blood glucose levels, while __________ raises blood glucose levels

Insulin; glucagon

A patient has hypertension, osteoporosis, hyperglycemia, immunosuppression, and an unusual accumulation of fat on the trunk and upper back. The diagnosis in the patient's chart says "Cushing's disease." The hormonal profile that you would most likely see in this patient is ____ levels of CRH, ____ levels of ACTH, and ____ levels of cortisol.

Low; low; high

Complete the table to compare the nervous system and endocrine system, the two control systems of the body.

NERVOUS SYSTEM Cells: Neurons Chemical Signal: Neurotransmitters Specificity of Action: Receptors on postsynaptic cell Speed of Onset: Seconds Duration of Action: Very brief unless neuronal activity continues ENDOCRINE SYSTEM Cells: Epithelial and others Chemical Signal: Hormones Specificity of Action: Receptors on target cell Speed of Onset: Seconds to hours Duration of Onset: May be brief or may last for days even if secretion ceases

Complete the sentences describing the hormonal control of thyroid hormone release.

Negative feedback occurs when the output of a pathway inhibits input to the pathway. Feedback loops are used extensively to regulate secretion of hormones in the hypothalamic-pituitary axis. An important example of a negative feedback loop is seen in the control of thyroid hormone secretion. The thyroid hormones thyroxine and triiodothyronine (T4 and T3) are synthesized and secreted by thyroid glands and affect metabolism throughout the body. Neurons in the hypothalamus secrete thyroid-releasing hormone (TRH), which stimulates cells in the anterior pituitary to secrete thyroid-stimulating hormone (TSH). TSH binds to receptors in the thyroid gland, stimulating synthesis and secretion of thyroid hormones. When blood concentrations of thyroid hormones increase above a certain threshold, TRH-secreting neurons in the hypothalamus are inhibited and stop secreting TRH. Inhibition of TRH secretion leads to shut-off of TSH secretion, which leads to shut-off of thyroid hormone secretion. As thyroid hormone levels decay below the threshold, negative feedback is relieved. TRH secretion starts again, leading to TSH secretion.

Which of the following describes an example of how hormones are regulated?

One hormone stimulates the release of another hormone.

Which type of secretion enters the interstitial fluid and affects neighboring cells in the same tissue?

Paracrine

A woman has a recent history of broken bones, ulcers, and kidney stones. Her physician finds that she has unusually high blood levels of calcium and immediately suspects that she is suffering from an excess of __________.

Parathyroid hormone

The hypothalamus uses nervous stimulation to control the secretion of hormones from which gland?

Posterior pituitary gland

Which gland secretes the antidiuretic hormone (ADH)?

Posterior pituitary gland

What group of compounds is produced from a specific type of fatty acid and has powerful effects on cells and tissues?

Prostaglandins

What must be present for any type of hormone to be able to act on a target cell?

Protein receptors

In comparison to the nervous system, the endocrine system responds __________ and its actions are __________.

Slowly; long-lasting

Complete the following sentences describing hormonal control of blood pressure.

Specific cells in the kidneys are able to respond to changes in blood pressure. If the blood pressure drops, these cells release the enzyme renin. The enzyme converts a blood protein called angiotensinogen to the peptide angiotensin I. An enzyme in the lungs converts the previous peptide into angiotensin II. One function of this last peptide is to stimulate the adrenal cortex to release the hormone aldosterone. This hormone acts to conserve sodium ions and, indirectly, water. This process will increase blood volume and blood pressure.

Which of the following is true about steroid hormones?

Steroid hormones can diffuse through the lipid bilayer.

Which of the following chemical classification of hormones is derived from cholesterol?

Steroids

What makes a cell a target cell for a hormone?

Target cells have specific receptors for the hormone.

An increase in the body's metabolic rate is the primary effect of what hormone?

Thyroid hormone

Which of the following hormones are produced by the anterior pituitary?

(1) prolactin (PRL), (2) growth hormone (GH), (3) adrenocorticotropic hormone (ACTH), (4) luteinizing hormone (LH), (5) follicle-stimulating hormone (FSH), and (6) thyroid-stimulating hormone (TSH)

1. Both steroid and protein hormones have their cell receptors in the same area of the cell. 2. Steroid hormones bind directly to the DNA. 3. What codes for the synthesis of proteins?

1. FALSE 2. FALSE 3. mRNA

1. Hormonal release is constant and is not effected by sensory input. 2. Antidiuretic hormone is a posterior pituitary hormone. 3. How is ADH transported to the target cells? 4. Why are both the kidneys and blood vessels able to respond to ADH?

1. FALSE 2. TRUE 3. Through the blood 4. Both have target cells with ADH receptors.

A 24-year-old female presents with fatigue, nausea, dehydration, increased urination, and abdominal pain. Two days prior, the patient was complaining of feeling light-headed and had a racing pulse. The results of blood tests determine that the patient has a high blood glucose level. She is diagnosed with type 1 diabetes. 1. What hormone controls the level of glucose in the blood? 2. What endocrine gland secretes this hormone? 3. High-blood glucose level, and type I diabetes, is a result of __________ secretion of the hormone.

1. Insulin 2. Pancreas 3. Over-secretion

1. In cases of higher-than-average insulin signaling, which of the following is likely to happen in target cells over time? 2. Exercising muscles upregulates glucose transporters independently of insulin signaling. Therefore, why is exercise a useful therapy for an individual with type II diabetes?

1. Insulin receptor downregulation 2. Exercise lowers blood glucose levels and therefore lowers insulin levels.

1. Prolactin has a permissive effect on oxytocin in breast tissue. If prolactin levels were high, but oxytocin receptors had been blocked by a drug, what would be the result? 2. Glucagon and insulin have antagonistic effects. Glucagon signaling results in an increase in blood glucose concentration. What do you expect is the result of insulin signaling? 3. When is hormone receptor downregulation likely to occur?

1. Oxytocin would have less of an effect on the target cells. 2. A decrease in blood glucose concentration 3. If a hormone is secreted at higher-than-usual levels

1. Which of these glands are found in the brain? 2. What hormone released from the endocrine gland would result in stimulation of growth of bone tissue? 3. Would this patient's symptoms be due to an increase or decrease in hormone secretion?

1. Pituitary gland 2. Growth hormone 3. Increase in hormone secretion

A 47-year-old male presents with weakness, dizziness upon standing, unexplained weight loss, and a loss of appetite, but with a craving for salty food. The doctor performs an ACTH stimulation test to determine if the patient has Addison disease. Addison disease is a hyposecretion of cortisol and aldosterone due to low production of the hormones. During the ACTH stimulation test, the doctor injects the patient with a synthetic form of ACTH and then measures blood levels of cortisol over the next hour. 1. What gland releases ACTH? 2. What is the action of ACTH? 3. If the ACTH stimulation test is positive for Addison disease, what is expected to happen to blood levels of cortisol one hour after the ACTH injection?

1. Pituitary gland 2. Stimulate the release of hormones from the adrenal cortex 3. The cortisol levels will be unchanged.

1. Epinephrine is a hormone that can't cross the plasma membrane. What classification of hormone is it? 2. Since the hormone can't enter the cell, what chemical serves as the second messenger for the hormone?

1. Protein or amine 2. cAMP

Hormones can be classified based on the chemical composition. Answer the following questions comparing steroid hormones and nonsteroid hormones. 1. Hormone enters the cell directly. 2. Receptor is inside the cell. 3. Stimulates transcription of DNA. 4. Receptor is on the cell membrane. 5. Causes metabolic changes in the cell.

1. Steroid 2. Steroid 3. Steroid 4. Non-steroid 5. Both

1. A steroid hormone enters a cell directly. 2. What is the purpose of the hormone-receptor complex moving into the nucleus? 3. What is the final effect of the steroid hormone activation of the cell?

1. TRUE 2. It will cause transcription of the DNA. 3. Production of proteins

1. Beta adrenergic receptor-blocking drugs are often called beta-blockers. These drugs prevent the hormone epinephrine from binding to its G-protein-coupled receptor. In the pathway activated by epinephrine, the activated G-protein would normally activate adenylate cyclase. When the drug is in use, which step(s) is/are prevented? 2. Mastoparan is a toxin derived from wasp venom. The effect of mastoparan is to prevent the G-protein from releasing GDP. When mastoparan is in a cell, which step(s) is/are prevented?

1. The activation of adenylate cyclase, the activation of the G-protein, and the activation of protein kinase A 2. The activation of adenylate cyclase

1. Why is there a higher level of thyroid hormone secreted in cases of pituitary tumors? 2. Would insulin, a hormone that is secreted in response to humoral stimulus, be affected by a pituitary tumor?

1. Thyroid hormone is secreted in response to hormonal stimulus from the anterior pituitary. 2. No, hormones controlled by humoral stimuli would not be affected directly by the pituitary tumor.

1. Drag the images into the correct order so that the steps in G-protein coupled receptor activation are represented correctly. 2. Which of the following describes an action of an activated G-protein?

2. Activation of adenylate cyclase or formation of phospholipase C

Drag each label to the appropriate gland to indicate whether the following hormones are released from the hypothalamus, the anterior lobe of the pituitary gland, or the posterior lobe of the pituitary gland.

HYPOTHALAMUS -TRH -GnRH -CRH ANTERIOR PITUITARY GLAND -GH -LH -ACTH -FSH -TSH -PRL POSTERIOR PITUITARY GLAND -OT -ADH

What are tropic hormones?

Hormones that stimulate other endocrine glands

What organ controls the response to stress, called the general adaptation syndrome?

Hypothalamus

Indicate whether each effect or symptom is associated with immediate "alarm" stage or long-term "resistance" stage of the stress response.

IMMEDIATE "ALARM" STAGE -Increased epinephrine secretion -Increased heart rate -"Fight or flight" response -Increased breathing -Redistribution of blood to working muscle -Water retention -ADH effects LONG-TERM "RESISTANCE" STAGE -Increased cortisol secretion -Immune system suppression

Where is the thymus gland located?

In the mediastinum

Which of the following is a physiological stressor?

Extreme heat

1. Which of these hormones would be able to cross the plasma membrane by simple diffusion? 2. Which of these hormones would require a carrier protein to travel within the blood?

1. Testosterone- a steroid hormone 2. Estrogen- a steroid hormone

A secretion of a "local hormone" which affects only the cell secreting it, is what type of secretion?

Autocrine

Decreasing levels of which hormone are associated with the declining strength that occurs with aging in the skeletal and muscular systems?

Growth hormone

Which of the following are the functions of the endocrine system?

Regulates water and electrolyte balance Regulates metabolism Controls reproduction and development Regulates growth

Which of the following is a mechanism or action of growth hormone and insulin-like growth factors?

-GH also enhances amino acid transport into cells; and to ensure that protein synthesis outpaces breakdown, it suppresses protein catabolism. -To provide energy for growing tissues, GH stimulates adipocytes to catabolize fat and release fatty acids and glycerol into the blood. -GH promotes Na+, K+, and Cl- retention by the kidneys, enhances Ca2+ absorption, and makes these electrolytes available to the growing tissues.

Identify the ways in which the anterior pituitary differs from the posterior pituitary.

-The anterior pituitary is also known as the adenohypophysis. -The anterior pituitary is stimulated by the hypothalamus via hormones that travel through the hypophyseal portal system. -Oxytocin is secreted by the anterior pituitary.

Indicate whether each effect or symptom is associated with short-term "alarm" or long-term "resistance" stage associated with stress.

ALARM STAGE -Epinephrine effects -Aldosterone levels rise -Angiotensin levels rise -ADH effects RESISTANCE STAGE -Cortisol effects -CRH and ACTH dominance

The hypothalamus regulates the activities of the __________ pituitary gland by __________.

Anterior; secreting hormones that inhibit or stimulate production of hormones

Keeping in mind the hormonal control of cortisol secretion as well as the functions of cortisol in stress, classify the statements on the left as being characteristic of either hyposecretion or hypersecretion of cortisol, by dragging them into the appropriate box at right.

CORTISOL HYPOSECRETION -Adrenal insufficiency is another name for this condition. -Autoimmune attack of the adrenal gland is one cause, which leads to elevated plasma CRH and ACTH levels. -Addison's disease is another name for a primary cause of this condition. -Symptoms may include hypotension and low blood sugar, weakness, fatigue, and loss of appetite. -Pituitary disease resulting in ACTH deficiency is a secondary cause of this condition. CORTISOL HYPERSECRETION -Cushing's syndrome is another name. -Symptoms may include osteoporosis, weak muscles, and bruised skin. -Causes some of the same symptoms as a person with diabetes, including hyperglycemia. -Symptoms may include hypertension and a redistribution of fat to the trunk, face, and back of neck.

What is the correct order hormones release during a stress response (general adaptation syndrome)?

CRH → ACTH → cortisol

Chemically, hormones synthesized from __________ are classified as steroid hormones and hormones synthesized from __________ are classified as amines, peptides, or proteins.

Cholesterol; amino acids

Which of the following would stimulate the secretion of melatonin from the pineal gland?

Darkness

Glands classified as __________ glands secrete substances (like sweat) outside the internal environment. Glands classified as __________ glands release their secretions (like hormones) into the bloodstream.

Exocrine; endocrine