Unit 3-The Endocrine System

What are 2 diseases of the adrenal glands?

1. Addisons Disease -undersecretion of cortisol and aldosterone -likely autoimmune (cells of adrenal cortex perceived as foreign) -Results in bronzing of skin, weight loss, fatigue. electrolyte imbalance, poor appetite and poor resistance to stress -may be due to inadequate secretion of ACTH 2. Cushings Syndrome -characterized by redistribution of body fat and fluid accumulation in face -caused by prolonged exposure to high cortisol levels -may result from a tumour on the adrenal cortex or anterior pituitary or from the use of glucocorticoid hormones to treat asthma, lupus, rheumatoid arthritis

What does the adrenal cortex secrete?

1. Gonadocorticoids -androgens, estrogens -secreted by adrenal cortex in men and women 2. Mineralcorticoids -mineral homeostasis and water balance -Aldosterone acts on kidney cells to increase the absorption of Na into blood and excretion of K into urine 3. Glucocorticoids -affect glucose homeostasis -act on liver to promote conversion of fat and protein into intermediate substances (eventually converted to glucose) -inhibit inflammatory response

What 6 hormones are synthesized and secreted by the anterior pituitary?

1. Growth hormone (GH) 2. Prolactin (PRL) 3. Thyroid stimulating hormone (TSH) 4. Adrenocorticotropic hormone (ACTH) 5. Follicle-Stimulating hormone (FSH) 6. Luteinizing hormone (LH)

What are the 5 major endocrine glands?

1. Pituitary 2. Thyroid 3. Parathyroid 4. Adrenals 5. Pineal

What are the 4 diseases that cause arise from thyroid issues?

1. Simple Goiter -enlarged thyroid gland -can result from diet deficient in iodine (needed for production of TH) -treated through iodine supplements or administration of TH 2. Cretinism -too little TH during fetal development/infancy -dwarfism and delayed mental/sexual development 3. Myxedema -too little TH in adulthood -fluid accumulation in facial tissues -decrease in alertness, body temp and heart rate 4. Graves' Disease -over secretion of TH -autoimmune disorder (antibodies mimic action of TSH) -symptoms: increased metabolic rate + heart rate, sweating, nervousness, weight loss, exophthalmos (protruding eyes due to fluid accumulation)

Amy just gave birth by cesarean section to a beautiful baby girl. All through her pregnancy, her mammary glands enlarged to prepare for milk production. However, in the day or two following parturition, Amy cannot eject a drop of the milk that is so obviously present in her breasts. What hormone is probably missing? A) oxytocin B) estrogen C) prolactin D) progesterone

A

Anton has to take insulin for his type 1 diabetes but his sister Maryam has another health issue and takes a pill. Anton knows that insulin is a protein but wants to know why he can't have a pill instead of all those nasty shots. Can you explain it to him? A) Proteins are digested by the stomach and intestines, so his insulin would be broken down before taking effect. B) Skin cells naturally destroy proteins. C) Steroids are water-soluble and require cAMP. D) Insulin only affects the circulatory system.

A

Eating a lot of shrimp would tend to decrease the incidence of which of the following conditions? A) simple goiter B) Grave's disease C) SAD D) myxedema

A

Govingee, 35 years old, has recently become lethargic and his skin feels very cool but puffy to the touch. When you take his pulse, you note that it seems abnormally low. What condition might Govingee have? A) low thyroid hormone B) excess calcitonin C) accumulating aldosterone D) low growth hormone

A

Lian, at 12 years old, was barely 3 feet tall. What hormone might she take to grow taller? A) growth hormone B) estrogen C) aldosterone D) calcitonin

A

Nadia, who is 25 years old, wants to be taller because she is just 5 feet tall. Of the choices given, which would be the wisest option for Nadia? A) Do nothing. B) Take injections of growth hormone. C) Use GHRH so she will have her own natural growth. D) Take thyroxin daily.

A

Norman ate his birthday cake with lots of sugary frosting so his pancreas secreted ________. A) insulin B) glycogen C) glucagon D) thyroxin

A

When a woman breast-feeds, oxytocin causes the milk to move from the mammary glands toward the nipples. What other organ might also react when a woman breast-feeds right after giving birth? A) uterus B) rectum C) thymus D) perilymph

A

Which of the following hormones may take part in one or more of these functions: influence daily rhythms, decrease jet lag, and influence sleep patterns? A) melatonin B) thymosin C) oxytocin D) growth

A

Which of the following might help in the treatment of impotence (inability to achieve an erection)? A) nitric oxide B) histamine C) prostaglandins D) growth hormone

A

The connection between the hypothalamus and the anterior pituitary is ________. A) circulatory B) neural C) via special ducts D) There is no connection.

A Posterior has neural connection

Tropic hormones secreted by the anterior lobe of the pituitary gland include _____.

A hormone produced by one endocrine gland that influences the activity of another endocrine gland is called a tropic hormone. The anterior pituitary produces 4 tropic hormones: 1. Thyroid Stimulating Hormone (TSH) -acts on the thyroid gland -stimulates synthesis and secretion of thyroid hormones 2. Adrenocorticotropic Hormone (ACTH) -controls synthesis and secretion of glucocorticoid hormones from cortex of adrenal glands 3. Follicle Stimulating Hormone (FSH) -in females, promotes the development of egg cells and secretion of estrogen -in males, promotes sperm production 4. Luteinizing Hormone (LH) -in females, causes ovulation and secretion of progesterone and estrogen -in males, stimulates production and secretion of testosterone

_____ causes the kidneys to remove water from the fluid destined to become urine.

ADH. Antidiuretic hormone (ADH; vasopressin) causes the kidneys to remove water from the fluid that will become urine. A deficiency of ADH results in diabetes insipidus, resulting in excessive urine production and dehydration.

An injection of ACTH would cause an increase in the release of which of the following hormones? A) thyroxin B) aldosterone C) growth hormone D) antidiuretic hormone

B

In the past, oxygen uptake in a patient was measured as a means of determining whether a certain endocrine gland was working properly. Which of the following glands was this method most likely assessing? A) pineal B) thyroid C) testes D) parathyroid

B

Parathyroid hormone causes the blood calcium level to rise, but calcitonin causes those levels to fall. The relationship between the two hormones is described as ________. A) expressive B) antagonistic C) synergistic D) permissive

B

Which is the hormone that stimulates growth by increasing cell size or rate of cell division? A) calcitonin B) growth hormone C) oxytocin D) tropic hormone

B

Which of the following functions in the body's inflammatory response prevents blood clots, regulates body temperature, and opens airways to the lungs? A) carotenoids B) prostaglandins C) leukotrienes D) melatonin

B

Melatonin. What gland secretes? What is the target tissue and what effect does this cause?

Gland: pineal (center of brain) Target: limbic system Effect: emotions/behavior. Pineal gets input from visual pathways, more secreted at night (light inhibits secretion). Promotes sleep, reduces jet lag and may slow ageing. Issues: too much can result in SAD, associated with winter and short days. Treated through repeated exposure to very bright light to inhibit melatonin secretion.

Anti-diuretic hormone (ADH). What gland secretes? What is the target tissue and what effect does this cause?

Gland: posterior pituitary stores + secretes, hypothalamus manufactures Target: distal convoluted tubule (DCT) Effect: reabsorption of water from fluid to become urine. (blood pressure) Disorders: diabetes insipidus, caused by deficiency of ADH. Causes excessive urine production and dehydration. Treated by ADH nasal spray.

Oxytocin (OT). What gland secretes? What is the target tissue and what effect does this cause?

Gland: posterior pituitary stores + secretes, hypothalamus manufactures Target: uterine smooth muscle Effect: -in females, stimulates uterine contraction during labor and milk ejection from mammary glands. -in males, may facilitate sexual behaviour and the transport of sperm

Testosterone. What gland secretes? What is the target tissue and what effect does this cause?

Gland: seminiferous, tubules Target: secondary sex organs Effect: development and maintenance

Thymosin. What gland secretes? What is the target tissue and what effect does this cause?

Gland: thymus Target: t-lymphocytes Effect: maturation

Thyroid Hormone: Triiodothreonine (T3) & Thyroxine (T4). What gland secretes? What is the target tissue and what effect does this cause?

Gland: thyroid produces in follicular cells Target: all cells, has broad effects Effect: regulates metabolic rate, heat production, maintains blood pressure, promotes normal functioning of several organ systems

Calcitonin. What gland secretes? What is the target tissue and what effect does this cause?

Gland: thyroid produces in parafollicular cells Target: kidney tubules and osteoblasts Effect: increases secretion of Ca++ into urine to lower levels of Ca++ in the blood. Stimulates absorption of calcium by bone and inhibits bone breakdown.

Which pancreatic hormone functions to increase blood glucose levels?

Glucagon. Stimulates the liver to break glycogen down into glucose, which is then released into the bloodstream.

Oversecretion of which hormone will result in acromegaly?

Growth hormone. Increased production of growth hormone in adults causes bones to thicken, a condition called acromegaly.

The chemical messengers of the endocrine system are called _____.

Hormones, the chemical messengers of the endocrine system, contact virtually all cells within the body. However, hormones affect only target cells, those cells with receptors that recognize and bind specific hormones.

Inhibiting hormones and releasing hormones are secreted by the _____.

Hypothalamus. Inhibiting and releasing hormones are produced by the hypothalamus and travel through capillaries to the anterior pituitary, where they regulate activity of the anterior lobe.

Red bone marrow cells respond to a hormone called erythropoietin. Why doesn't a liver or kidney cell respond to this hormone?

Kidney and liver cells do not contain the protein receptor that binds erythropoietin. Only target cells, which contain the receptors for a hormone, can respond to that hormone.

What are locally acting chemical messengers?

Local signalling molecules that act quickly on adjacent cells. Examples: -Neurotransmitters -Growth factors (stimulate cells to grow, develop and multiply) -Nitric Oxide/NO (gas, vasodilator, may also aid in peristalsis and act as a neurotransmitter)

What hormone stimulates the release of a future egg cell by the ovaries?

Luteinizing

When the increased blood level of the hormone inhibits its further release, what mechanism is at work?

Negative feedback. A negative feedback mechanism occurs when an increased blood level of the hormone inhibits its further release (ex. when blood glucose levels drop, insulin not secreted), whereas a positive feedback mechanism occurs when the outcome of a process further stimulates the process (ex. oxytocin and uterine contractions during childbirth).

Which endocrine gland might be involved in seasonal affective disorder, which occurs in some people during winter, when the days are shorter?

Pineal. The pineal gland secretes melatonin in response to dark. Melatonin causes lethargy, sleepiness, and depression.

When the response of a tissue to the combination of two hormones is much greater than its response to either individual hormone, the interaction is said to be _____.

Synergistic. Antagonistic hormones oppose each other. In permissive interactions, one hormone must be present for another hormone to exert its effects. In synergistic interactions, the effects of the two hormones are much greater than their additive values.

The thymus gland lies on top of the _____ and plays an important role in _____.

heart; immunity. The thymus gland lies on top of the heart and plays an important role in immunity. Its hormones, Thymopoietin and Thymosin, influence the maturation of white blood cells called T lymphocytes.

Parathyroid hormone stimulates osteoclasts. This would _____ calcium levels in the blood.

increase. Osteoclasts break down bone, releasing calcium into the bloodstream.

The pineal gland produces melatonin, which should have circulating levels that _____ at night compared to daylight hours.

increase. The levels of circulating melatonin should be greater at night than during daylight hours, as it promotes sleep.

Prostaglandins are _____.

one type of local signaling molecule. Prostaglandins are lipid molecules continually released by the plasma membranes of most cells. Prostaglandins have many diverse effects, but they act locally near the site of their release on adjacent target cells. At least 16 different prostaglandins function in the human body. They influence the reproductive system (ex. menstrual cramps), inflammatory response, blood clotting and body temperature.

As you sleep your blood glucose levels should normally decline. However, this hormone will cause your liver to release more of the sugar. A) thyroxin B) adrenaline C) glucagon D) insulin

C

Eric was working very hard in the dry, hot boiler room and sweating a lot. Under these conditions, which of the following might Eric be experiencing? A) He would have decreased hydrocortisone. B) He would have increased oxytocin. C) He would have increased antidiuretic hormone. D) He would have decreased thyroxin.

C

Gian-Carlo is going to have part of his adrenal cortex removed because of a tumor. After the surgery he may need ________. A) melatonin and insulin B) oxytocin C) cortisol D) calcitonin

C

In males, the primary source of estrogens is the ________. A) hypothalamus B) heart C) adrenal cortex D) ovaries

C

Sandhu has type 1 diabetes so he must frequently inject himself with insulin. He has to be careful not to inject himself too often or with too much of the hormone because this vital chemical will virtually disappear from his bloodstream. A) glycogen B) oxycontin C) glucose D) oxygen

C

Sometimes postmenopausal women are given a prescription for which of the following to help them maintain their bone calcium? A) parathyroid hormone B) thyroid hormone C) calcitonin D) insulin

C

This type of hormone characteristically requires a second messenger. A) lipid-soluble B) steroid C) water-soluble D) prostaglandin

C

The adrenal medulla secretes hormones that function to prolong the effects of the _____ nervous system.

sympathetic. The adrenal medulla secretes epinephrine and norepinephrine as hormones, which prolongs the fight-or-flight response of the sympathetic nervous system.

_____ results from too little TH during fetal development or infancy, while too little TH in adulthood results in _____.

Cretinism; myxedema. Graves' disease is an autoimmune disease resulting from oversecretion of TH.

What is an example of a common second messenger?

Cyclic adenosine monophosphate (cAMP). When hormones bind to receptors on target membranes, they convert ATP to cAMP. cAMP then activates enzyme cascade which activates proteins already in the cell.

Cancer cells often fail to respond to certain hormones because they lack these cell membrane features important in binding with that specific hormone. A) DNAs B) dockers C) targets D) receptors

D

Hanna, 18 years old, is over 6 feet tall. She has an x-ray taken that shows that her long bones are continuing to lengthen. Eventually, a thorough examination shows that she has a tumor growing in her ________. A) posterior pituitary B) pineal gland C) adrenal medulla D) anterior pituitary

D

Inflammatory processes can be painful and even dangerous if they continue inappropriately. Which of the following would control those processes? A) thyroid hormone B) growth hormone C) vasopressin D) cortisol

D

Leukocytosis-promoting factor, among other things, acts to encourage the movement of white blood cells to the site of an injury. What hormone opposes this action?A) epinephrine B) insulin C) TH D) cortisol

D

Maria has been in labor for 12 hours and her obstetrician thinks that it is time to artificially induce birth. What hormone will the physician inject? A) estrogen B) vasopressin C) prolactin D) oxytocin

D

Sue has begun to lactate but she has not recently given birth. Which of the following might be causing this abnormality? A) excess estrogen B) progesterone production C) hyperthyroidism D) pituitary tumor

D

Vlad, 28 years old, is a slender, jumpy man with eyes that seem to bulge out of their sockets. His heart rate is unusually fast. Which of the following conditions does Vlad most likely have? A) Addison's disease B) acromegaly C) Cushing's syndrome D) Grave's disease

D

Too little thyroid hormone secretion causes what symptoms?

Decreased body temperature and heart rate. Undersecretion of thyroid hormone decreases metabolic activity of body cells.

Growth hormone stimulates growth, especially in muscles and bones. What specific structure in bones contains many target cells for this hormone?

Epiphyseal plate. The epiphyseal plate is the growth plate in children's long bones. It responds to growth hormones, as well as other hormones.

True or false? Water-soluble hormones pass through the plasma membrane on their own.

False. Only small, fat-soluble (hydrophobic) substances can pass through the phospholipid bilayer of the plasma membrane on their own. Water-soluble hormones are made of amino acids and bind to protein receptors on the plasma membrane. They are considered first messengers and exert their effects through second-messenger systems. They stimulate second messengers within cells which carry out the effect of the hormone.

Growth Hormone (GH). What gland secretes? What is the target tissue and what effect does this cause?

GH is secreted by the anterior pituitary and regulated by the hypothalamus through the secretion of 2 hormones: 1. Growth Hormone Releasing Hormone (GHRH) which stimulates the release of GH 2. Growth Hormone Inhibiting Hormone (GHIH) which inhibits the release of GH Target: bone, muscle, fat, cartilage Effect: growth of tissues via stimulating the rate of cell division and increase in cell size Disorders: gigantism, acromegaly, pituitary dwarfism

Glucagon. What gland secretes? What is the target tissue and what effect does this cause?

Gland: Alpha Islets cells of pancreas Target: liver and skeletal muscle Effect: stimulates breakdown of glycogen to glucose in liver and stimulates formation of glucose from lactic acids and AA's (increase in blood glucose)

Insulin. What gland secretes? What is the target tissue and what effect does this cause?

Gland: Beta Islets cells of pancreas Target: all cells, liver and skeletal muscle Effect: stimulates transport of glucose into muscle cells, white blood cells and connective tissue cells. Inhibits breakdown of glycogen to glucose. Inhibits formation of glucose from FA's and AA's. (decreases blood glucose)

Cortisol. What gland secretes? What is the target tissue and what effect does this cause?

Gland: adrenal cortex Target: all cells Effect: glucose metabolism

Aldosterone. What gland secretes? What is the target tissue and what effect does this cause?

Gland: adrenal cortex (outer region of adrenal glands on top of kidneys) Target: kidney tubules Effect: reabsorption of water and Na (blood pressure)

Epinephrine. What gland secretes? What is the target tissue and what effect does this cause?

Gland: adrenal medulla (inner region of adrenal glands on top of kidneys) Target: cardiac muscle, arteriole and bronchiole smooth muscle Effect: increases heart rate and blood pressure (?)

Norepinephrine. What gland secretes? What is the target tissue and what effect does this cause?

Gland: adrenal medulla (inner region of adrenal glands on top of kidneys) Target: cardiac muscle, arteriole and bronchiole smooth muscle Effect: increases heart rate and blood pressure (?)

Latinizing Hormone (LH). What gland secretes? What is the target tissue and what effect does this cause?

Gland: anterior pituitary Target (males): interstitial cells in testes Target (females): mature ovarian follicle Effect (males): testosterone secretion Effect (females): ovulation

Follicle stimulating hormone (FSH). What gland secretes? What is the target tissue and what effect does this cause?

Gland: anterior pituitary Target (males): semi- iferous tubules of testes Target (females): ovarian follicle Effect (males): sperm production Effect (females): follicle/ovum maturation

Prolactin (PRL). What gland secretes? What is the target tissue and what effect does this cause?

Gland: anterior pituitary Target: -In females, stimulates mammary glands to produce milk. Can cause infertility and lactation when childbirth has not occurred. -In males, involved in the production of mature sperm in testes. Can lead to sterility in excess. Effect: produce milk

Adrenocorticotropic hormone (ACTH). What gland secretes? What is the target tissue and what effect does this cause?

Gland: anterior pituitary Target: adrenal cortex (outer region of adrenal glands on top of kidneys) Effect: Controls the synthesis and secretion of glucocorticoid hormones from the cortex

Thyroid Stimulating Hormone (TSH). What gland secretes? What is the target tissue and what effect does this cause?

Gland: anterior pituitary Target: thyroid Effect: secrete hormones

Progesterone. What gland secretes? What is the target tissue and what effect does this cause?

Gland: corpus luteum Target: uterine endometrium Effect: preparation for implantation (thickens, glandular, vascular)

Estrogen. What gland secretes? What is the target tissue and what effect does this cause?

Gland: ovarian follicle Target: secondary sex organs Effect: development and maintenance

Parathyroid Hormone (PTH). What gland secretes? What is the target tissue and what effect does this cause?

Gland: parathyroids (4 small round masses at back of thyroid gland) Target: kidney tubules and osteoclasts Effect: Stimulates osteoclasts to break down bone. Stimulates kidneys to remove calcium from urine. Alters rate of Ca absorption from GI system. Inhibits osteoblasts. (increases blood Ca++) Issues: -Undersecretion: nervousness and muscle spasms -Oversecretion: pulls too much Ca from bone which weakens it and elevates blood Ca levels too high. Can lead to kidney stones (Ca deposits) and decreased activity of nervous system.

True or false? Exocrine glands secrete their products into ducts, leading to body surfaces or cavities.

True. Exocrine glands secrete their products into ducts, leading to body surfaces, cavities, or spaces within organs, whereas endocrine glands contain secretory cells that release their products, hormones, into extracellular fluid, where they diffuse into the bloodstream.

True or false? Steroid hormones are lipid soluble.

True. Steroid hormones are lipid soluble. Steroids cross through the plasma membrane of target cells and combine with a receptor molecule in the cytoplasm or nucleus, forming a hormone-receptor complex. In the nucleus, the hormone-receptor complex attaches to DNA and activates certain genes to synthesize specific proteins which then alter cellular activity

Which type of diabetes mellitus is becoming increasingly common in American children?

Type 2. Type 2 diabetes mellitus is caused by obesity and inactivity, which are becoming increasingly common in American children.

Which hormone stimulates the mammary glands to produce milk, but in excess can cause infertility and lactation when birth has not occurred?

Prolactin. Secreted by the anterior lobe of the hypothalamus and stimulates milk production. Oxytocin stimulates milk ejection from the mammary glands.