Chapter 7 the endocrine system PDF

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The endocrine system- endocrinology The endocrine system can be broken down into signal senders, the signals they send, and the signals’ outcomes. The main signal senders are the endocrine glands, which include the hypothalamus, pituitary, thyroid, parathyroid, adrenal, pancreas, and gonads (ovaries and testicles). Endocrine glands specifically send chemical signals to different parts of the body. These chemical signals, which are hormones, generally cause slower, subtler changes than the nervous system, which uses electric signals. The signals travel through the rest of the body via the bloodstream, but only the intended cells in the body respond to these hormonal signals. These cells are keyed with receptors that fit with the hormone—just like two matching puzzle pieces. The hormone then signals the cell to perform a desired job, such as releasing another hormone, releasing or taking in nutrients, or changing the speed at which the body makes certain proteins. The end result is that the endocrine system can adjust the levels of nutrients in the blood, excrete excess nutrients, help the body respond to its environment, and direct growth and development. For example, the pancreas secretes hormones that help the body control the level of sugar in the blood. The adrenal glands, thyroid gland, and parathyroid gland keep critical minerals like calcium and sodium in balance. The adrenal glands also make hormones for the fight-or-flight response to danger. The name adrenal describes where the gland is located in the body. Growth hormone helps the body grow to adult height and affects metabolism. The gonads make hormones that help drive sexual development. The endocrine system even stimulates milk production in new mothers.

7.1 Word parts of the endocrine system

Word roots for endocrine glands As you recall, the signal makers and senders of the endocrine system are called glands. They are located throughout your body, including in your brain, in the area above your kidneys, in your genitals, and in the front part of your neck. The glands are linked to the nervous system via the hypothalamus. It gets its name from its location in the brain, resting just below the thalamus. While part of the brain, the hypothalamus also acts as a gland in that it makes and releases hormones that direct the other glands. The main role of the hypothalamus is to direct the activity of the pituitary gland. It can cause the pituitary to make and release its chemical signals via chemicals called releasing hormones (example: gonadotropin-releasing hormone). The pituitary gland is made of two parts: the anterior (front) and posterior (back) pituitary. The anterior pituitary gland is the origin for many very important hormones. These hormones travel by blood and stimulate many other endocrine glands, including your thyroid gland, adrenal glands, and gonads. Located in the front part of your neck resting just below the Adam’s apple is your thyroid gland and just behind it, the parathyroid glands. The thyroid gland makes hormones (T3 and T4) that affect the body’s metabolism, as well as a hormone that helps control the level of calcium in the blood. The parathyroid glands also make a hormone that works along with the thyroid hormone to control the blood’s calcium level. The glands used for excessive exocrine responses are pancreas, salivary, and sweat The pancreas, an interesting gland that sits just under your stomach, is both an endocrine gland and a gastrointestinal organ. As an endocrine gland, it sends hormones directly into the bloodstream that help keep the blood sugar level in balance. As a gastrointestinal organ, it secretes enzymes by ducts (exocrine) directly into your intestines to help with digestion. The adrenal gland gets its name from its location in your body, as it lies on top of your kidneys. The adrenal gland has an inner layer that makes the fight-or-flight hormone, adrenaline. Its outer layer, or cortex, makes two general types of hormones. One type keeps mineral levels in balance and also maintains the proper volume of water and salt in the blood. The other helps keep blood sugar levels in balance and affects your body’s response to inflammation. The gonads help with reproduction and with expression of male and female characteristics. The male gonads are the testes. They produce the male hormone testosterone. Ovaries, the female gonads, secrete estrogens, which help the body develop female attributes and help prepare the body for pregnancy.

Term

root

examples

Gland

aden/o

Adenoma, adenopathy

Adrenal gland

adren/o, adrenal/o

Adrenarche, adrenalitis “On the kidney” Ad / renal On or to / kidney

Outer surface

cortic/o

Corticotropic Latin word bark or husk

Gonads (sex organs)

gonad/o

Gonadopathy, gonadogenesis Gon or gen in genesis is greek for “to create”

Pancreas

pancreat/o

Pancreatitis, pancreatolith Greek words pan (all) and kreas (flesh)

Pituitary gland

pituitar/o, hypophys/o

Latin word for “mucus” Hypo / physis (hypophyso) Under / growth

Thymus

thym/o

Thymoma, thymectomy

Thyroid

thyr/o, thyroid/o

Thyrotoxin, thyroidectomy Thyro / oid Shield / resembling Gland resembling a shield

Sugar

gluc/o, glucos/o, glyc/o

Glucocorticoid, glucosuria, hypoglycemia

To secrete

crin/o

Endocrine, exocrine Endo- “To secrete internally” Exo- “To secrete externally”

Word roots for secretions, chemicals, and blood work Once the signals (hormones) are made in the endocrine organs, they wait to be secreted (crino) to their target body part. Endocrine signals travel via the bloodstream. The pituitary gland makes many hormones that encourage other endocrine glands in the body to work. Adrenocorticotropic hormone (ACTH) stimulates the outer part of the adrenal gland. Thyroid-stimulating hormone (TSH) stimulates the thyroid gland. Luteinizing (LH) and follicle-stimulating hormone (FSH)stimulate the gonads. The pituitary gland also makes growth hormone and prolactin. The thyroid makes three very important hormones: T4, T3, and calcitonin. T4 and T3 affect the body’s metabolism. An overactive thyroid (hyperthyroidism) leads to a higher-than-normal metabolism—everything speeds up. As a result, a person suffering from hyperthyroidism experiences weight loss, increased hunger, diarrhea, and nervousness. On the opposite end, for

people with hypothyroidism,everything slows down. They typically experience weight gain, decreased energy and appetite, and constipation. Calcitonin is a hormone that encourages the uptake of calcium in the blood into bone. This keeps the level of calcium in the blood from getting too high. The parathyroid glands make parathyroid hormone.This hormone has the opposite effect of calcitonin. It helps keep the level of calcium in the blood from getting too low. As you recall, the pancreas is both a digestive organ and an endocrine organ. The endocrine part of the pancreas makes two hormones that work together to keep the level of sugar in the blood in balance. Insulindecreases the level of sugar in the blood. It encourages cells to open up to the blood sugar (glucose) and take it in. Glucagon works against insulin. It tells the liver to make more sugar and thus increases the level of sugar in the blood. The adrenal gland creates hormones in two parts—the inner part or the outer part. The inner part of the adrenal gland makes epinephrine, which was once known as adrenaline. Many people know adrenaline as the chemical that surges in danger and helps mothers lift cars off their babies. While it doesn’t truly gift people with superpowers, it does play an important role in the fight-or-flight response by increasing your heart rate and opening your airways to get more oxygen. Norepinephrine, also made in the adrenal gland, causes very similar changes. The outer part of the adrenal gland (cortex) also makes very important hormones. ACTH stimulates the cortex to release corticosteroids, which are steroid hormones made in the cortex. The two types of corticosteroids are hormones dealing with mineral balance (mineralocorticoids) and hormones dealing with sugar balance (glucocorticoids). ACTH and Corticotropin stimulate the cortex of the adrenal gland. Adrenal is the term used for the location of a gland Last, the adrenal glands are an extra location for secretion of the sex hormones, testosterone and estrogen. The two types of corticosteriods used in the adrenal glands are glucocorticoids and mineralocorticoids. The main source of these hormones, however, is the gonads. The gonads of men and women make different hormones. In men, the testes make testosterone. The testes trigger the production of sperm and the development of masculine body characteristics, like increased muscle and facial hair. Ovaries, the female gonads, secrete estrogens, which cause the development and release of eggs as well as the development of feminine attributes, like breasts and wide hips. Measuring the level of certain hormones and how they affect the patient’s blood is one way of checking the function of the endocrine system. The most common example is checking the glucose level in the blood (glycemia). These levels may be high (hyperglycemia), low (hypoglycemia), or normal (euglycemia). Another body fluid that is often measured is a patient’s urine. Substances like sugar (glucosuria) or ketones (ketonuria) may be found in the urine.

Term

root

example

Hormone

hormon/o

Hormonopoesis Greek for “to rush” or “push”

Ketone body (substance that increases in the blood… toxic chemicals)

ket/o

Ketosis, ketogenetics Increases in the blood from a faulty carbohydrate metabolism

Term

suffix

Examples

Stimulating hormone

-tropin

Thyrotropin Greek word “to turn”

Blood condition

-emia

Glycemia, calcemia

Urine condition

-uria

Polyuria

7.2 Patient history, problems, complaints The symptoms a patient experiences from an endocrine problem all depend on which organ is affected. Patients with pituitary problems may present to a health care provider with growth disturbances. This can be on either extreme, from the abnormally large (pituitary gigantism) or small (pituitary dwarfism). If the extra growth is disproportionate in the face and long bones of the body, it is known as acromegaly. Patients with an overactive thyroid (hyperthyroidism) have a higher-than-normal metabolism— everything speeds up. As a result, a person suffering from hyperthyroidism experiences weight loss, increased hunger, diarrhea, and nervousness. Some also have bulging eyes (exophthalmos). On the opposite end, for someone with hypothyroidism, everything slows down. Patients with this disease typically experience weight gain, decreased energy, hair loss, decreased appetite, and constipation. They may also experience swelling and puffiness in the hands and face. This grouping of symptoms is called myxedema. Both hyperthyroidism and hypothyroidism can present with an enlarged thyroid (goiter). Decreased pancreatic endocrine activity leads to diabetes. Patients with diabetes may complain of excessive thirst (polydipsia), excessive urination (polyuria), and constant hunger (polyphagia), with an unexpected weight loss. Premature sexual traits may represent a problem with the adrenal gland or the gonads. Males may experience premature puberty from an overactive adrenal gland (adrenal virilism). Females with the same problem may report facial hair (hirsutism). When a female has a hyperactive gonad (hypergonadism) she may present with periods (menarche) or breast development (thelarche) at a premature age. Females with underfunctioning gonads may complain of lack of

menstruation (amenorrhea). Males may experience breast development (gynecomastia). This is very common in puberty.

Term

Definition

Word analysis

Adenalgia

Pain in a gland

aden/ algia gland/ pain

Adrenal virilism

Development of male secondary sexual characteristics caused by excessive secretion of the adrenal gland

Adrenal viril / ism Adrenal man/ condition

adrenarche

Beginning of adrenal secretion (at puberty)

adren/ arche adrenal/ beginning

menarche

Beginning of menstruation

Hirsutism

Excessive growth of facial and body hair in women

From latin, for “shaggy”

Term

Definition

Word analysis

Amenorrhea

Lack of menstrual flow

A / meno/ rrhea no/ menstrual/ flow

Gynecomastia

Development of breast tissue in males

gyneco/ mast/ ia woman/ breast/ condition

Hypergonadism

Condition in which there is excessive secretion of the sex glands

hyper/ gonad/ ism over/ gonad/ condition

Hypogonadism

Condition in which there is undersecretion of the sex glands

hypo/ gonad/ ism under/ gonad/ condition

menarche

Beginning or first menstruation

men/ arche menstrual/ beginning

thelarche

Beginning of breast development

thel/ arche breast/ beginning

Gonad

Pancreas ( Pancreat is root for pancreatectomy )

Term

Definition

Word analysis

Hypoglycemic

Pertaining to low blood sugar

hypo/ glyc/ em/ ic under/ sugar/ blood/ pertaining to

Pancreatalgia

Pain in the pancreas

pancreat/ algia pancreas/ pain

Polydipsia

Excessive thirst

poly/ dips/ ia excessive/ thirst/ condition

Polyphagia

Excessive eating

poly/ phag/ ia excessive/ eat/ condition

Polyuria

Excessive urination

poly/ uria Excessive/ urine condition

Term

Definition

Word analysis

acromegaly

Abnormal enlargement of the extremities

acro/ megaly Extremities / abnormal enlargement

Galactorrhea

Discharge of milk

galacto/ rrhea milk/ discharge

Pituitary dwarfism

Abnormally short height caused by undersecretion of growth hormone from the pituitary gland.

Pituitary

Pituitary gigantism

Abnormal secretion of growth hormone from the pituitary

Abnormally tall height caused by oversecretion of growth hormone from the pituitary

Thyroid Term

Definition

Word analysis

Exophthalmos

Protrusion of the eyes out of the eye socket

ex/ ophthalmos out/ eye

Goiter (common cause: iodine deficiency)

Swollen thyroid gland

From Latin for “gutter” (meaning throat)

Thyrocele

Another name for goiter

thyro/ cele thyroid/ tumor

Thyromegaly

Enlargement of the thyroid

thyro/ megaly thyroid/ enlargement

Thyroptosis

Downward displacement (drooping) of the thyroid

thyro/ ptosis thyroid/ drooping condition

7.3 Observation and discovery When a patient is examined for endocrine problems, many of the findings are the same things that the patient noticed and reported. The examiner may notice that the patient is much taller or shorter than average, or that he or she is overweight or underweight. Patients may have incorrect sexual traits, like a male with breast development. Patients may have swelling or fat that is more pronounced in certain parts of their bodies. Endocrinology testing- effect of hormones in blood, levels of hormone in blood Much of what is left for data collection relates to laboratory testing. There are numerous tests in endocrinology. The tests check either the level of hormones in the blood or their effect. Many of the hormones take on similar names to the gland that made them. For example, one of the hormones that the parathyroid glands makes is parathyroid hormone. Adrenal glands make adrenaline (also known as epinephrine). They may take on the name from the part of the gland in which they are made. Cortisol is made in the cortex of the adrenal gland. Other hormones are named for the organ they “turn on.” These types of hormones are known as -tropins. For example, adrenocorticotropic (corticotropin) hormone stimulates the cortex of the adrenal gland. Other -tropins include gonadotropins (LHand FSH) and thyrotopin (TSH). There are two general fluids that can be checked to see the results of hormones: blood and urine. Any lab level that represents a substance in the blood ends in -emia. For instance, magnesemia is the level of magnesium in the blood. If the level is higher than normal it has the prefix hyper-, and if it is lower than normal it has the prefix hypo-. For instance, if a patient has a lower-than-expected level of magnesium in his or her blood, the patient has hypomagnesemia. Any lab level for a substance in the urine ends with -uria. If a patient has calcium in his or her urine, the patient has calciuria. One specific nutrient the endocrine system manages is the sugar level in the blood. It controls how fast sugar is being made (gluconeogenesis) and how fast it is broken down (glycolysis). If someone has low blood sugar (hypoglycemia) then the body releases a hormone to increase the production of sugar and slow the breakdown of sugar. Ketones are a byproduct of this.

Blood and urine conditions

Term

Definition

Word analysis

Acidemia

Abnormal acidity of the blood

acid/ emia acid/ blood condition

Alkalemia

Abnormal alkalinity of the blood

alkal/ emia alkali/ blood condition

Calciuria

Calcium in the urine

calci/ uria calcium/ urine condition

Chloremia

Increased chloride in the blood

chlor/ emia chloride/ blood condition

Euglycemia

Good blood sugar

eu/ glyc/ emia good/ sugar/ blood condition

Glucosuria

Sugar in the urine

glucos/ uria sugar/ urine condition

Hypercalcemia

Excessive calcium in the blood

hyper/ calc/ emia over/ calcium/ blood condition

Hypercholesterolemia

Excessive cholesterol in the blood

hyper/ cholesterol/ emia excessive/ cholesterol/ blood condition

Hyperglycemia

High blood sugar

hyper/ glyc/ emia excessive/ sugar/ blood condition

Hyperkalemia

Excessive potassium in the blood

hyper/ kal/ emia over/ potassium/ blood condition

Hyperlipidemia

Excessive fat in the blood

hyper/ lipid/ emia Excessive / fat/ blood condition

Hypernatremia

Excessive sodium in the blood

hyper/ natr/ emia excessive/ sodium/ blood condition

Hyperphosphatemia

Excessive phosphate in the blood

hyper/ phosphat/ emia excessive/ phosphate/ blood condition

Hypoglycemia

Low blood surgar

hypo/ glyc/ emia under/ sugar/ blood condition

ketonuria

Ketone bodies in the urine

keton/ uria

ketone/ urine condition Polyuria

Excessive urination

poly/ uria exce...