Med Surg 2, chapter 38, endocrine

Your patient's labs came back showing a decrease in hormones T3 and T4. The doctor seems to think it is due to her diet. What element is she most likely lacking in her diet?

Iodine! The thyroid needs iodine to make T3 and T4. Iodine is NOT made in the body and so we must eat adequate amounts of it on our diet. Some foods that have iodine are salt, tuna, eggs, seaweed, dairy, cod, shrimp

What does the term *catecholamines* refer to?

it is a term used to describe a group of hormones that act on the sympathetic nervous system, specifically epinephrine and norepinephrine

The body has several different glands that produces hormones: the ovaries, the testes, thyroid, parathyroid, thymus, pituitary, and the adrenal glands. Where are the adrenal glands located? They are composed of an outer and an inner part. Both parts secrete different hormones. What is the name for the outer part of the adrenal glands? What hormones do they secrete? What is the inner part called ? What hormones are secreted from there?

located superior to the the kidneys outer part of the adrenal gland is called the *ADRENAL CORTEX*. They secrete *aldosterone (a type of mineralocorticoid), cortisol (a type of glucocorticoid), and sex hormones (also called gonadocorticoids) Inner part of the adrenal glands is called the *ADRENAL MEDULLA*. It secretes *epinephrine and norepinephrine (these are also referred to as catecholamines)*

Most people have 4 parathyroid glands. Where are they located? What is the hormone that the parathyroid gland secretes? What does this hormone do?

they are embedded in the posterior side of the thyroid PTH (parathyroid hormone) increases the reabsorption of calcium and phosphate from the bone to the blood (*in simpler words, PTH increases the amount of calcium in the blood*) . It also increases absorption of the calcium in the small intestines and activates vit d.

Calcitonin is released from which gland? When does the body release calcitonin? Where does the hormone called PTH secrete from? Why would the body release PTH?

thyroid when blood calcium levels are too high PTH is the parathyroid hormone which means PTH is secreted from the parathyroid ! When blood calcium levels are too high.

The pituitary gland hangs from a stalk that is attached to the hypothalamus. What is another name for the hypothalamus? Sometimes (most likely due to cancer) , the hypothalamus might be removed. What is the medical term for the removal of the hypothalamus?

hypophysis hypophysectomy

For the hormone cortisol to be released, what is the "domino effect" that must happen first?

1.) the secretion of *CRH* (corticotropin releasing hormone) occurs first 2.) which initiates the secretion of *ACTH* (adrenocorticotropic hormone) 3.) which then causes the release of *cortisol*!! *CRH -----> ACTH-----> cortisol*

For the hormones T3 and T4 to be released , what is the "domino effect" that must happen first?

1.) the secretion of *TRH* (thyrotropin releasing hormone) happens first 2. Which initiates the secretion of *TSH* (thyroid-releasing hormone) 3.) the TSH then initiates the secretion of *T3 and T4* !! *TRH -----> TSH -----> T3 and T4*

The ANTERIOR pituitary gland produces several different hormones including ACTH. Explain what ACTH does. In order for ACTH to be secreted, it depends on ANOTHER hormone to start it. What is the name of this particular hormone?

ACTH (adrenocorticotropic hormone): stimulates secretion of cortisol and other hormones from the adrenal cortex. Cortisol is needed in times of stress (such as during pregnancy, injury, illness, etc) when the body needs more glucose in order to fight those stresses. Cortisol stimulates release of glucose from liver, breakdown of fat, and proteins CRH (corticotropin-releasing hormone). Without this, ACTH cannot be released

The pituitary gland is often known as the "master gland" because it secretes hormones to control other hormones and bodily functions. There are two lobes in the pituitary: anterior and posterior Name the glands that are produced in the posterior pituitary. (Know what each one does!)

ADH (aka, vasopressin): this is a vasoconstrictor. Not only does it increase BP by constricting blood vessels but it also increases water retention which also causes BP to go up Oxytocin: stimulates contractions during labor and also aids in the release of milk from the mammary glands (this is the only positive feedback hormone, all other hormones are negative feedback acting)

Cortisol is secreted by which part of the adrenal gland: cortex or the medulla? It is usually released when? ANOTHER hormone must be secreted in order to START the secretion of cortisol. What is the name of that hormone?

ADRENAL cortex when the body undergoes physiological stress (such as during exercise, trauma, illness, hypoglycemia, etc) because the brain requires an increased demand of glucose. Cortisol saves extra glucose for the brain and forces the body to use fats and excess amino acids for energy ACTH (adrenocorticotropic hormone) is needed to START cortisol **remember that for ACTH to work, the secretion of CRH (corticotropin-releasing hormone) must also be secreted.**

The pancreas are one of the many glands in the body that secretes hormones. The pancreas are composed of mainly 3 different cells that secrete a different hormone Name each cell and what hormone they secrete.

Alpha cells: secretes glucagon which convers glycogen into glucose and uses excess amino acids and fats for energy (used when blood sugar is low) Beta cells: secretes insulin to force glucose into the cells (used when blood sugar is high) Delta cells: secretes somatostatin (used to inhibit either glucagon or insulin when there are too much)

True or false: Urine tests cannot be used in determining the function of the endocrine system.

FALSE. Urine tests CAN be used. Urine specimens can be used to determine how much hormones or hormone by-products that are excreted in the urine especially with cortisol and vanillylmandelic acid (which are end-products of catacholamines) Specific gravity of urine can also be helpful. A SG of 1.001 can indicate diabetes insipidus.

The ANTERIOR pituitary gland produces several different hormones including FSH. Explain what FSH does. In order for FSH to work, it depends on ANOTHER hormone to start it. What is the name of that hormone? What is the name of the hormone that STOPS the secretion of FSH

FSH (follicle-stimulating hormone): it is found in both men and women. In women: As the name suggests, it STIMULATES the FOLLICLES to "grow" the egg. It also increases secretion of estrogen by the follicles in men: It helps in the maturation/production of sperm to start: GnRH (gonadotropin releasing hormone) to stop: inhibin

You are looking after a patient who is abnormally short in stature. She looks to be about just 4 feet tall. Which hormone is she mostly likely lacking?

GH (growth hormone)

The pituitary gland is often known as the "master gland" because it secretes hormones to control other hormones and bodily functions. There are two lobes in the pituitary: anterior and posterior Name the glands that are produced in the anterior pituitary.

GH (growth hormone) TSH (thyroid stimulating hormone) ACTH (adrenocorticotropic hormone) Prolactin FSH (follicle-stimulating hormone) LH (Luteinizing hormone)

The ANTERIOR pituitary gland produces several different hormones including GH. Explain what GH does. There are hormones that are released to either START the secretion of growth hormone or STOP growth hormone. What is the name of the 2 hormones that start and stop GH?

GH (growth hormone): increases cell division in tissues that are capable of mitosis, helps the body to "grow" as the name suggests. It also helps in energy production by increasing the absorption of amino acids for protein synthesis and release of fats from adipose tissue to start it: GHRH (growth hormone-releasing hormone) to stop it: GHIH (growth hormone-inhibiting hormone)

There are several tests that can be used to determine the functioning of the thyroid gland. One of them is called a *thyroid scan*. Explain what this entails. Another test to test the thyroid gland is called a *radioactive iodine uptake test*

It is used to detect the presence of tumors or nodules. A radioactive substance is either injected orally or injected. The material is taken up by the thyroid. After a specific time , a scan is done which will show either hot spots or cold spots. Hot spots means there are BENIGN nodules. Cold spots indicates malignancy. **a small amount of radioactive material is given for this and the risk to the pt is minimal* It is similar to the thyroid scan. Several scans are done within a 24 hour period after administration of radioactive iodine. The amount of iodine taken up by the thyroid can determine how active it is. This is helpful in determining hyperthyroidism!

The ANTERIOR pituitary gland produces several different hormones including prolactin. Explain what prolactin does.

It stimulates milk production in the mammary glands

The ANTERIOR pituitary gland produces several different hormones including LH. Explain what LH does. In order for LH to work, it depends on ANOTHER hormone to start it. What is the name of that hormone?

LH (luteinizing hormone): It is found in both men and women in women: it causes ovulation (releasing of the egg). Once the egg "drops", FSH also causes that follicle to become *corpus luteum* (Remember that corpus luteum is the group of cells that form on the ovary to produce estrogen and progesterone to prepare the endometrium for pregnancy) in men: It increases secretion of testosterone by the testes. To start it: GnRH (gonadotropin releasing hormone)

Where is the pituitary gland located? There are two primary lobes on it. Name them and explain the difference between each.

Located in the brain, suspended by a stalk which hangs from the hypothalamus Anterior pituitary: it produces its own hormones and responds to the hormones released by the hypothalamus Posterior pituitary: stores and releases hormones

The body has several different glands that produces hormones: the ovaries, the testes, thyroid, parathyroid, thymus, pituitary, and the adrenal glands. What are the 3 different hormones that are secreted by the thyroid? Explain what each one does.

T3 and T4: increases the energy production from all food types and increases protein synthesis (in simpler words, T3 and T4 is responsible for increasing the metabolic rate to produce energy and body heat) Calcitonin: decreases the reabsorption of calcium and phosphate from the bones to the blood (in simpler words, calcitonin DECREASES the levels of calcium in the blood.)

True or false: Normal aging usually does NOT lead to serious hormone deficiencies or illness.

TRUE. Unless there are pathological problems, the endocrine system in older adults should continue to function adequately despite of age

The ANTERIOR pituitary gland produces several different hormones including TSH. Explain what TSH does. For TSH to secrete, ANOTHER hormone must also exist in order to start TSH. What is the name of that hormone?

TSH (thyroid stimulating hormone): stimulates the thyroid to secrete T3 and T4 which increases metabolic rate by increasing cellular respiration of glucose and fatty acids (in simpler terms, T3 and T4 help produce energy and heat) TRH (thyrotropin releasing hormone). Without this, TSH will NOT be able to secrete

There are several different tests that can be ordered to test for abnormalities of the endocrine system. What are some examples of blood tests that can be ordered? A *stimulation test* may also help determine endocrine gland function. What does a stimulation test entail? A *suppression* test also help determine endocrine gland function. Explain what a suppression test is.

TSH, T3, T4, calcitonin, parathyroid hormone, calcium, phosphorus, GH, etc. *(refer to page 884-885 for more examples of tests and their normal ranges)* A substance is injected to stimulate a gland. The hormone that is secreted by that gland is measured to determine how well it responded to the stimulation. For example, in a TRH stimulation, TRH is injected. If the pituitary gland responds appropriately, TSH should secrete. If the thyroid gland responds appropriately to the TSH, then T3 and T4 levels should rise. Failure for TRH to stimulate TSH and TH Indicates a problem with the pituitary or the thyroid. It is the OPPOSITE of the stimulation test. A substance is injected that is expected to SUPPRESS the release of a hormone. If the expected hormone does NOT get suppressed then an issue is indicated.

The ADRENAL MEDULLA secretes epinephrine and norepinephrine to help us during times of "fight or flight". What hormones does the ADRENAL CORTEX secrete? What do those hormones do?

aldosterone and cortisol aldosterone: increases reabsorption of sodium by the kidneys to the blood (in simpler terms, Aldosterone is used to retain sodium so that water can also be retained. This causes BP to go up) It also excretes potassium thru the urine (remember that potassium and sodium have an inverse relationship: when one goes up, the other goes down) Cortisol: increases use of fats and excess amino acids for energy so that the supply of glucose is saved for the brain to use (this happens mainly during times of stress when the brain needs an increased amount of glucose for energy) and it acts as an anti-inflammatory by blocking the effects of histamine

Which hormone can act as an anti-inflammatory?

cortisol

Even though the endocrine system should function adequately regardless of age, decrease in hormone secretions do happen as our bodies get older. Explain what happens to the endocrine system as we age.

decrease in GH (growth hormone) which leads to decrease in muscle mass and increase in fat storage. Decrease in TSH and thyroid hormone causes decreased basal metabolic rate which leads to decreased energy decrease in insulin secretion leads to glucose intolerance

The hormones ______________ and ____________ are secreted from the adrenal medulla which assists in the "fight or flight" component. How do these hormones help us when dealing with stressful events such as running from a bear?

epinephrine and norepinephrine Epinephrine: increases HR and force of contractions, dilates the bronchioles, decreases peristalsis, increases conversion of glycogen into glucose, causes vasodilation in skeletal muscles , increases use of fats for energy, and increases cell respiration norepinephrine: causes vasoconstriction in skin, viscera, and skeletal muscles (it mobilizes the body and brain for action)

During a physical assessment, *palpation* can be an important part in assessing the endocrine system. What is the ONLY gland that we can palpate? When should palpation be AVOIDED with this particular gland? When performing a focused assessment of the endocrine system. What kind of data should we collecting and observing for?

thyroid gland thyroid gland should NOT be palpated with pt who has uncontrolled hyperthyroidism which can stimulate excretion of additional TH the pt's mood and affect and LOC (hypothyroidism can cause depression, hyperthyroidism can cause nervousness, hypoglycemia can cause agitation), inspect and palpate the thyroid for enlargement, look at eyes for *exophthalmos*, posture (too much glucocorticosteroids can cause buffalo hump), is the pt overweight or underweight (thyroid problems can affect wt)?, presence of tremors (hyperthyroidism and hypoglycemia can cause tremors), assess skin for any dryness or moisture (hypoglycemia can cause cold clammy skin, hypothyroidism can cause dry skin), hair, observe the skin for discoloration (DM can cause poor circulation and cause discoloration in the lower extremities. Addison's Disease can cause a bronzy skin tone) , assess peripheral pulses (hyperthyroidism can increase HR), skin turgor (dehydration can be caused by Addison's Disease, DM, or diabetes insipidus) any changes in pulse or temp or BP ? (hyperthyroidism causes temp and pulse to elevate. Increased catecholamines can cause BP to increase) *for more, refer to pg 883-884*