Review for Lecture Exam 1 Endocrine

List the four types of cells that release pancreatic hormones, along with the hormones that each cell type releases. Describe the effects of each hormone released.

1. Alpha cells hormone- glucagon target- liver, adipose tissue hormonal effect- mobilizes lipid reserves;promotes glucose synthesis and glycogen breakdown in liver; elevates blood glucose concentration regulation control: stimulated by low blood glue concentrations inhibited by GH-IH delta cells 2. Beta Cells hormone-insulin target-most cells hormonal effect- facilitates uptake of glucose by target cells; stimulates formation and storage of lipids and glycogen regulatory control: stimulated by high blood glucose concentrations 3. Delta Cells hormone- GH-IH(somatostatin) target- other islet cells. digestive epithelium hormonal effect- inhibits insulin and glucagon secretion; slows rate of nutrition absorption and enzyme secretion along digestive tract regulation control- stimulated by protein-rich meal; mechanism unclear 4. f- cells hormone- pancreatic polypeptide target- digestive organs effect- inhibits gallbladder contraction stimulated by protein rich meals and by parasympathetic stimulation

List the three different categories of hormones, along with examples of each. For each of these categories, describe whether the hormones can freely diffuse across plasma membranes, whether they bind intracellular receptors or receptors at the plasma membrane, and whether they generate second messengers.

1. Amino Acid Derivative -small molecules structurally related to amino acids - synthesized from the amino acid tyrosine and tryptophan - example include thyroid hormone, epinephrine, norepinephrine, and dopamine. - the primary hormone made from tryptophan is melatonin produced by the pineal gland. 2. Peptide Hormones - chains of amino acids. Most peptide hormone are synthesized as pro hormones(inactive molecules are converted to active hormone before or after they are secreted) - Peptide hormones are chains of amino acids. They are synthesized as prohormones—inactive molecules that are converted to active hormones either before or after they are secreted. • Peptide hormones are divided into two groups: 1. Group 1: Glycoproteins - more than 200 amino acids long, with carbohydrate side chains. Glycoproteins include: thyroid-stimulating hormone (TSH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) from the anterior lobe of the pituitary gland, as well as several hormones produced in other organs. 2. Group 2: large and diverse, including hormones from short polypeptide chains, such as antidiuretic hormone (ADH) and oxytocin, to small proteins such as growth hormone (GH) and prolactin (PRL). This group includes all the hormones secreted by the hypothalamus, heart, thymus, digestive tract, pancreas, and posterior lobe of the pituitary gland, as well as most of the hormones secreted by the anterior lobe of the pituitary gland. 3. Lipid Derivatives There are two classes of lipid derivatives: 1. Eicosanoids: derived from arachidonic acid 2. Steroid hormones: derived from cholesterol • Eicosanoids are small molecules with a five-carbon ring at one end. These compounds are important paracrine factors that coordinate cellular activities and affect enzymatic processes in extracellular fluids. • Leukotrienes are eicosanoids released by activated white blood cells, or leukocytes. Leukotrienes are important in coordinating tissue responses to injury or disease. • Prostaglandins, a second group of eicosanoids, are produced in most tissues of the body. Prostaglandins are involved primarily in coordinating local cellular activities. In some tissues, prostaglandins are converted to thromboxanes and prostacyclins, which also have strong paracrine effects. • Steroid hormones are lipids structurally similar to cholesterol. They are released by male and female reproductive organs (androgens by the testes, estrogens and progestins by the ovaries), the adrenal glands (corticosteroids), and the kidneys (calcitriol). • In the blood, steroid hormones are bound to specific transport proteins in the plasma. They remain in circulation longer than do secreted peptide hormones. The liver gradually absorbs these steroids and converts them to a soluble form that can be excreted in the bile or urine.

List the four different types of intercellular communication. For each type, describe the structures through which it communicates, which chemicals it uses for communication, and how widespread its effects are.

1. Direct Communication - through gap junction - ions, small solutes, lip-soluble materials - usually limited to adjacent cells of the same type that are interconnected by connexons 2. Paracrine Communication - though extracellular fluid -paracrine factors -primarily limited to a local area, where paracrine factor concentration are relatively high target cells must have appropriate receptors 3. Endocrine Communication - through the blood stream -hormone - target cells are primarily in other tissues and organs and must have appropriate receptors 4. Synaptic Communication -across synapse -neurotransmitters - limited to very specific are; target cells must have appropriate receptors

List the different organs with secondary endocrine functions, along with the hormones each organ produces.

1. Intestines(digestive tract)- release and absurd nutrients. 2. the kidneys(urniary system)- release steroid hormone calcitroil, the peptide hormone erythropoietin, and the enzyme rennin. 3. the heart(cardiovascular system)- the endocrine cells in the heart are cardiac muscle cells in the walls of the atria and the ventricles. they secrete natriuretic peptides. Promotes the loss of Na and water by kidneys. 4.the thymus( lymphatic system)- hormones are important in developing and maintaining immune defenses. Thymosin is the na,e originally given to an extract from the thymus. 5. the gonads( testes and ovaries reproductive system)- interstitial cells of the testes produce the male hormone known as androgens. Testosterone is the most important androgen. Estrogen are produced in ovaries under FSH and LH. Progesterone.

Hormones can change the functions of a target cell in a number of different ways

A. It can cause the target cell to make a new protein that it wasn't making before. B. It can cause the target cell to make more or less of a protein. C. It can cause the target cell to change the shape of an existing protein, which turns it "on" or turns it "off".

Describe the hormone signaling pathway for calcitonin, step-by-step. Your description should include the stimulus for hormone release, all structures involved, all hormones released, the targets of each hormone and the effects of each hormone.

C cells produce the hormone calcitonin which help regulate Ca2 concentration in body fluids. the net effect is a drop in Ca2 concentration in body fluids. Coalition inhibits osteoclast and stimulates exertion by the kidneys Calcitonin (produced by parafollicular or "C" cells) is a peptide hormone that can lower blood calcium by inhibiting osteoclast activity and stimulating Ca2+ uptake and incorporation into the bone matrix ( at pharmacological doses, otherwise it has no physiological effect in humans).

Identify the parathyroid glands on images and describe their location in the body.

Four parathyroid glands are embedded in the posterior surface of the thyroid gland. The chief cells produce parathyroid hormone (PTH) in response to lower- than normal concentrations of Ca2+.

Describe the hormone signaling pathway for glucocorticoids, step-by-step. Your description should include all structures involved, all hormones released, the targets of each hormone and the effects of each hormone.

Glucocorticoid secretion is regulated by negative feedback: the glucocorticoids released have an inhibitory effect on the production of corticotropin-releasing hormone (CRH) in the hypothalamus, and of ACTH in the anterior lobe. Figure 18-8a • Glucocorticoids accelerate the rate of glucose synthesis and glycogen formation, especially in the liver. Adipose tissue responds by releasing fatty acids into the blood, and other tissues begin to break down fatty acids and proteins instead of glucose. • Glucocorticoids show anti-inflammatory effects: they inhibit the activities of white blood cells and other components of the immune system.

List the hormones involved in growth

Growth Hormone (GH): effects are most apparent in children where GH supports muscular and skeletal development. In adults GH assists in the maintenance of normal blood glucose concentrations and in the mobilization of lipid reserves. • Thyroid hormones: if these hormones are absent during fetal development or for the first year after birth, the nervous system will fail to develop normally and mental retardation will result. If T4 concentrations decline before puberty, normal skeletal development will not continue. • Insulin: without insulin the passage of glucose and amino acids across cell membranes will be drastically reduced or eliminated. • Parathyroid Hormone (PTH) and Calcitriol: promote the absorption of calcium salts for subsequent deposition in bone. Without adequate levels of both hormones, bones will be weak and flexible. • Reproductive Hormones: the sex hormones (androgens in males, estrogens in females) stimulate cell growth and differentiation in their target tissues. Differential growth induced by each hormone accounts for gender-related differences in skeletal proportions and secondary sex characteristics.

List organs with secondary endocrine functions, along with the hormones they produce.

Heart- atrial natriuretic peptide(ANP), Brain natriuretic Peptide (BNP Thymus(undergoes atrophy during adulthood) thymosins Adipose Tissue- Leptin Digestive Tract- Decretnes numerous hormone involved in the coordination of system function, glucose, metabolism, and appetite) Kidneys- erythropoietin(EPO), calcitriol Gonads- Testes(androgens, testosterone, inhibin), Ovaries(estrogens, progesterone, inhibin)

Identify the macroscopic and microscopic structures of the adrenal glands on images and describe their locations in the body.

One adrenal (suprarenal) gland lies along the superior border of each kidney. The gland is subdivided into the superficial adrenal cortex and the inner adrenal medulla.

Describe the effects of aging on the endocrine system.

The endocrine system undergoes few functional changes with advanced age. The major changes include a decline in the concentration of growth hormone and reproductive hormones. • Some endocrine tissues become less responsive to stimulation even though circulating hormone levels remain within normal limits. • Changes in peripheral tissues may make them less responsive to some hormones.

Describe the three different ways that the hypothalamus controls hormone release. List specific hormones whose release is controlled by each of the three ways.

The hypothalamus regulates the activities of the nervous and endocrine system, by: 1. secreting regulatory hormones which control the actives of endocrine cels in the anterior love of the pituitary gland 2. acting as an endocrine organ by releasing hormone in the bloodstream at the posterior lobe of the pituitary gland 3. exerting direct neural control over the endocrine cells of the adrenal medullae The hypothalamus is crucial in regulating hormone action. Everything basically begins with the hypothalamus, because the hypothalamus controls the pituitary, which controls most other glands in the endocrine system. So when the hypothalamus receives a signal from the central nervous system, it either releases hormones to the pituitary or stimulates the pituitary to make the hormones that get released into the bloodstream and affect other glands in the endocrine system. This causes the other glands to release hormones as well, and it has a top-down effect until the target body system / organ / cell is regulated.

Describe how the endocrine and nervous systems are different from one another. List the characteristics that these two systems have in common.

The nervous system performs short term crisis management where as the endocrine system regulars lonergerterm metabolic process. - both systems rely on the release of chemicals that bind to specific receptors on their target cells - the two systems share many chemical messengers. for example norepinephrine and epinephrine are called hormones when release in blood stream but neurotransmitters when released across synapse. - both systems are regulated mainly by negative feedback control mechanism - the two systems share a summon goal: to preserve homeostasis by coordinating and regulating the activities of other cells, tissues and organs, systems

Overall purpose of the endocrine system

The purpose of the endocrine system is to sense changes in the body's conditions (particularly internal conditions) and to coordinate a response.

Identify the macroscopic and microscopic structures of the thyroid gland on images and describe their locations in the body.

The thyroid gland lies anterior to the thyroid cartilage of the larynx and consists of two lobes connected by a narrow isthmus.

Describe the causes of, effects of, and treatments for Type I and Type II diabetes. Explain how Type I and Type II diabetes are similar and how they are different.

Type 1: is characterized by inadequate insulin production by the pancreatic beta cells. Person with type 1 diabetes require insulin to live and usually multiple injections daily or continuous infusion through insulin pump or other devices. tis form of diabetes accounts for approximately 5% of cases it usually develops in children and young adults type II: is the most common for of diabetes mellitus. Most people with this form of diabetes produce normal amounts of insulin, at least initially, but their tissues do not respond properly, a condition known as insulin resistance. Type 2 disbedties is associated with obesity and weight loss through diet and excrete can be an effective treatment especially when coupled with oral medicines.

Describe how negative feedback regulates hypothalamus hormone release, giving specific examples.

When blood glucose levels climb, the pancreas increases in secretion of insulin, a hormone that stimulates glucose uptake and utilization. As insulin levels rise, glucose levels decline, reducing the stimulation of these insulin securing cells. As glucose levels return to normal, the rate of insulin secretion returns to resting levels. This is an example of negative feedback. When you ingest a huge amount of sugar, there is excess glucose in the bloodstream. The pancreas releases insulin, which binds with receptors in the cell membrane and causes glucose to be taken into the cells where it can be used or stored. Once the glucose levels decrease in the bloodstream, insulin is no longer released by the pancreas. So in summary: glucose increases in blood stream à pancreas detects the increase and releases insulin à insulin increases in blood stream à glucose decreases in blood stream. This is a negative feedback.

For each region or zone of the adrenal gland list which hormones are released, the stimuli that cause hormone release, the targets of the hormones, and the effects of the hormones.

Zona Glomerulosa hormone: mineralocorticoids primary aldosterone targets: kindeys hormonal effect: increases renal reabsoirabtion of NA and water especially sin the resent of ADH and accelerate urninary loss of potassium Zona Fasciculta: Hormone: glucocorticoids, cortisol, hydrocortisone, corticosterone target: most cells hormonal effect: increases rate of glucose and glycogen formation by the liver; released of minion acids from skeletal muscles and lips from adipose tissues; proimies peripheral utilization in tissues; antiiflamatory regulatory control; stimulated by ACTH from anterior love of the pituitary gland Zona recticlaris: hormone: androgens target: most cells: hormonal effect: adrenal androgens stimulate the development of public hair in boys and girls before puberty Adrenal Medulla: epinephrine and norepinephrine, most cells, increases cardiac activity, stimulated by the sypathetic preganglionic fibers.

Hormones can have one effect at a low concentration and another effect at

a high concentration.

antagonistic

antagonistic (opposing) effects PTH and calcitonin or insulin and glucagon.

A cell can respond to multiple different hormones at the same time

as long as it has the receptors for those hormones.

Hormones are typically released near __________for efficient entry into the bloodstream.

capillaries

Target cells can reduce their number of receptors (called ____________, which decreases their sensitivity to a specific hormone. Target cells can also increase their number of receptors (called __________), which increases their sensitivity to a specific hormone.

down-regulation up-regulation

Adipose tissue secretes

leptin (a feedback control for appetite) and resistin (which reduces insulin sensitivity). Leptin must be present for there to be normal levels of GnRH and gonadotropin synthesis.

List the diseases caused by hyposecretion or hypersecretion of each hormone listed in Table 18-8. Describe the symptoms of each disease.

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permissive

permissive effects, in which one hormone is necessary for another to produce its effect epinephrine does not change energy consumption unless thyroid hormones are also present in normal concentration

Identify the structures of the pituitary gland on images and describe their locations in the body.

this is the pituitary gland or hypothesis.. This small oval gland lies nestled with the sella turicica, a depression in the sphenoid mine. it is connected by the infundibulum. it released the nine important peptide hormones. Seven come front the anterior lobe and two from the posterior lobe.

Identify the pineal gland on images and describe its location in the body.

• The pineal gland lies in the posterior portion of the roof of the third ventricle. It contains pinealocytes, which synthesize the hormone melatonin.

synergistic

synergistic (additive) effects glucose sparing action of GH and glucocortoids

Describe the hormone signaling pathway for parathyroid hormone, step-by-step. Your description should include the stimulus for hormone release, all structures involved, all hormones released, the targets of each hormone and the effects of each hormone.

the four parathyroid gland embedded in the posterior surface of the thyroid gland secrete parathyroid hormone to elevate blood calcium. It stimulates osteoclasts, accelerating mineral turnover and the release of Ca2+ from bone. 2. It inhibits osteoblasts, reducing the rate of calcium deposition in bone. 3. It enhances the reabsorption of Ca2+ at the kidneys, reducing urinary losses. 4. It stimulates the formation and secretion of calcitriol at the kidneys. The effects of calcitriol complement or enhance those of PTH, but one major effect of calcitriol is the enhancement of Ca2+ and PO43- absorption by the digestive tract.

Hormones are inactivated when:

they diffuse out of the bloodstream and bind to receptors on their targets. B. they are absorbed and broken down by the liver or the kidney. C. they are broken down by the enzymes of the blood or interstitial fluids.

Describe the hormone signaling pathway for thyroid hormone, step-by-step. Your description should include the stimulus for hormone release, all structures involved, all hormones released, the targets of each hormone and the effects of each hormone.

1. Iodide ions are absorbed from the diet at the digestive tract and are delivered to the thyroid gland by the bloodstream. 2. The iodide ions diffuse to the apical surface of each follicle cell, where they are converted to an activated form of iodide (I+) by the enzyme thyroid peroxidase. 3. Tyrosine molecules to which iodide ions have been attached become linked by covalent bonds, forming molecules of thyroid hormones that remain incorporated into thyroglobulin. The hormone thyroxine (T4) contains four iodide ions. Triiodothyronine (T3) contains three iodide ions. Eventually each molecule of thyroglobulin contains four to eight molecules of T3 or T4 hormones or both. • The major factor controlling the rate of thyroid hormone release is the concentration of TSH in the circulating blood. • Under the influence of TSH, the following steps occur: Figure 18-11a 1. Follicle cells remove thyroglobulin from the follicles by endocytosis. 2. Lysosomal enzymes break the thyroglobulin down, and the amino acids and thyroid hormones enter the cytoplasm. The amino acids are then recycled and used to synthesize more thyroglobulin. 3. The released molecules of T3 and T4 diffuse across the basement membrane and enter the bloodstream. 4. Most T3 and T4 molecules entering the bloodstream become attached to transport proteins called thyroid-binding globulins (TBGs). Most of the rest of the T3 and T4 in the circulation is attached to transthyretin (thyroid-binding prealbumin - TBPA) or to albumin, one of the plasma proteins. Only the small quantities of thyroid hormones that remain unbound are free to diffuse into peripheral tissues.

List the hormones released by anterior pituitary and by the posterior pituitary. For each of these hormones, describe the stimulus that causes hormone release, along with the targets and effects of each hormone.

Anterior Pituitary Lobe: 1. thyroid-stimulating hormone(TSH) -release from thyroid hormone -promotes the pituitary secretion of TSH 2. Adrenocorticotropic Hormone(ACTH) - stimulates the release of glucocorticoids by the adrenal cortex. -Corticotropin releasing hormone from the hypothalamus causes the pituitary to secret acth 3. Follicle Stimulating Hormone(FSH) - stimulate follicle development and estrogen secretion in female and sperm production. 4. Luteinizing Hormone(LH) - causes ovulation and progesterone production in female androgen production in males. -Gonadotropin-releasing hormone GnRH from the hypothalamus promotes the pituitary secretion of both FSH and LH 5. Prolactin(PRL) - from the pituitary, togeth with other hormones, stimulates both the development of the mammary glands and milk production. 6. Growth Hormone(GH or somatotropin) - from the pituitary stimulates cell growth and replication through release of somatomedin to IGFs from liver cells. 7. Melanocyte-stimulating hormone(MSH) - may be secreted by the pars intermedia of the pituitary during fetal development, early childhood, pregnancy, or certain diseases. Stimulates melanocytes to produce melanin. Posterior Pituitary Lobe: both have non hypothalamic regulation hormone because the they are transported along axons 1. Antidiuretic Hormone(Adh) - also known as vasopressin is released in response to variety of stimuli, most notable a rise in solute concentration win the blood or fall in blood volume or blood pressure. - a rise in the solute concentration stimulates special neurons in the hypothalamus. -primary function is to act on the kidneys to retain water and decrease urniation. 2. Oxytocin(OXT) - stimulates smooth muscle concentration in the wall of the uterus, promoting labor and delivery. After delivery oxytocin promotes the ejection of milk. - targets uterus, mammary gand, ductus defers and prostate gland.

Hormones in responses to stress.

Any condition that threatens homeostasis is a stress. • Our bodies respond to a variety of stress-causing factors through the general adaptation syndrome (GAS), or stress response. • The GAS can be divided into three phases: 1. the alarm phase 2. the resistance phase 3. the exhaustion phase

List the organs of the endocrine system, as well as the hormones that each organ produces.

Hypothalamus- ADH, OXT, and regulatory hormones Pituitary gland- anterior lobe: ACTCH, TSH, GH, PRL, FSH, LH, MSH, posterior lobe: oxytocin and antidiuretic hormone Thyroid Gland: Thyroxine(T4), Triiodothyronine(T3), Calcitonin(CT) Adrenal Gland- Medulla(epinephrine and norepinephrine), Cortex( Cortisol, corticosterone, aldosterone, androgens) Pancreatic Islets- insulin, glucagon Pineal Gland- melatonin Parathyroid Gland- Parathyroid Hormone

List the hormone released by the pineal gland, as well as the cells that release this hormone and the stimulus for hormone release. Describe the effects of hormone release by the pineal gland.

Pinealocytes(Cell) secrets melatonin. -play a role in human sexual maturation - very effective antioxidant - influence circadian rhythms

Describe the three phases of the general adaptive syndrome, including hormones released, the responses attempted in each phase, and how one phase leads to the next phase.

The Alarm Phase, p. 626 • During the alarm phase, an immediate response to the stress occurs, directed by the autonomic nervous system. • In the alarm phase: 1. energy reserves are mobilized, mainly in the form of glucose 2. the body prepares to deal with the stress by "fight or flight" responses • Epinephrine is the dominant hormone in the alarm phase. • Characteristics of the alarm phase include: 1. increased mental alertness 2. increased energy consumption 3. mobilization of energy reserves (glycogen and lipids) 4. changes in circulation: increased blood flow to skeletal muscles, decreased blood flow to the skin, kidneys, and digestive organs 5. drastic reduction in digestion and urine production 6. increased sweat gland secretion 7. increases in blood pressure, heart rate, and respiratory rate The Resistance Phase, p. 626 • If a stress lasts longer than a few hours, the individual enters the resistance phase of the GAS. • Glucocorticoids are the dominant hormones of the resistance phase. • Energy demands remain higher than normal in the resistance phase. Glycogen reserves are nearly exhausted after several hours of stress. • The secretions of the resistance phase are coordinated to achieve four integrated results: 1. mobilization of remaining lipid and protein reserves 2. conservation of glucose for neural tissues 3. elevation and stabilization of blood glucose concentrations 4. conservation of salts and water, and the loss of K+ and H+. • The body's lipid reserves are sufficient to maintain the resistance phase for weeks or even months. If starvation is the primary stress, the resistance phase ends when lipid reserves are exhausted and structural proteins become the primary energy source. If another stress is the cause, the resistance phase ends due to complications by hormonal side effects: 1. glucocorticoids have anti-inflammatory actions that slow wound healing and increase the body's susceptibility to infection 2. ADH and aldosterone conserve fluids that over time produce elevated blood volumes and higher-than-normal blood pressures 3. the adrenal cortex may become unable to produce glucocorticoids, eliminating the ability to maintain acceptable blood glucose concentrations • Poor nutrition, emotional or physical trauma, chronic illness, and damage to key organs can hasten the end of the resistance phase. The Exhaustion Phase, p. 628 • The exhaustion phase begins when homeostatic regulation breaks down . • Unless corrective actions are taken almost immediately, the failure of one or more organ systems will prove fatal. • Mineral imbalances contribute to the existing problems with major systems. • The inability to sustain the endocrine and metabolic adjustments of the resistance phase will cause death.

List the steps of the formation of thyroid hormones, in order.

Thyroid hormones enter target cells by means of an energy dependent transport system, and they affect almost every cell in the body. • Thyroid hormones bound to cytoplasmic receptors are held in storage until intracellular levels of thyroid hormone decline. Thyroid hormones bound to mitochondria increase ATP production. Thyroid hormones bound to receptors in the nucleus activate genes that control energy utilization. • The calorigenic effect: the cell consumes more energy resulting in increased heat generation. • In growing children, thyroid hormones are essential to normal development of the skeletal, muscular, and nervous systems. • The thyroid gland is primarily responsible for a strong, immediate, and short-lived increase in the rate of cellular metabolism.

Overview of the structures and processes that function from stimulus to response in endocrine system

To accomplish this function, endocrine signaling always begins with a stimulus. Examples of stimuli can include changing levels of calcium in the blood or changes in blood volume. Special regions of an endocrine organ will then sense these stimuli and respond by releasing hormones into the blood. For example, when the levels of calcium in the blood get too low, the parathyroid gland will sense this drop and will release parathyroid hormone into the blood.

Identify the structures of the hypophyseal portal system on images and describe their locations.

ensures that these regulatory factors reach the intended target cells in the pituitary before they enter the general circulation

Describe the hormone signaling pathway for insulin, step-by-step. Your description should include the stimulus for hormone release, all structures involved, all hormones released, the targets of each hormone and the effects of each hormone.

insulin is a peptide hormone released by beta cells when blood glucose concentration exceeds normal levels. The hormone affects cellular metabolism in a series of steps that begin when insulin sends to receptor proteins on plasma membrane of a target cell. insulin: -accelerates glucose uptake -accelerates glue utilization -stiulates glycogen formation -stimulates amino acid absorption and protein synthesis Insulin is secreted when glucose is abundant; the hormone stimulates glucose utilization to support growth and the establishment of carbohydrate (glycogen) and lipid (triglyceride) reserves. The accelerated use of glucose soon brings circulating glucose to normal limits.

integrative

integrative effects, in which hormones produce different, but complementary, results calcitriol and parathyroid hormone on tissue

Some hormones are released in

pulses, and target cells vary their responses based on the frequency of the pulses.

A single hormone can alter the function of multiple different target organs at the same time, because it is

raveling throughout the body in the bloodstream.

Hormones can bind to

special transport proteins in the blood, which prevents the breakdown of these hormones and can prolong their effects.

Describe the hormone signaling pathway for glucagon, step-by-step. Your description should include the stimulus for hormone release, all structures involved, all hormones released, the targets of each hormone and the effects of each hormone.

stimulates the breakdown of glycogen in skeletal muscle and liver cells 2. stimulates the breakdown of triglycerides in adipose tissue 3. stimulates the production of glucose in the liver when glucose concentration decrease below normal, alpha cells release gluten to mobilize energy reserves. When glucagon binds to a receptor in the target cells' plasma membrane the hormone activates adenylate class. As we have seen, cAMP acts a second messenger that activates cytoplasmic enzymes. - stimulates the breakdown of glycogen in skeletal muscles and liver cells -stimulating the breakdown of triglycerides in adipose tissue -stimulating the production and release of glucose by the liver.