Endocrine System

This is Unit Thirteen of Medical Terminology: the endocrine system. Twenty-six entries, and the book calls it the most regular unit in the course. Units One through Four supply the machine — combining forms, the joining rules, the universal suffixes and prefixes, and the orientation vocabulary. Unit Twelve supplies one root this unit leans on: thalam slash o, from the brain block, because the pituitary is defined by sitting below the hypothalamus. The system is glands and the chemicals they release, and the vocabulary splits the same way. Fourteen combining forms open the unit: eight naming glands, six naming what those glands regulate. Only two suffixes are new. Crine names secreting, and tropin names a hormone that stimulates another gland. Everything else is borrowed — emia and ism from Unit Two, hyper and hypo from Unit Three, and one suffix carried across from the cardiovascular unit. Then the pathology, which arrives as three pairs. Sugar above range against sugar below it. A thyroid overactive against one underactive. And two conditions that share the word diabetes and share nothing else. By the end you will be able to do five things. One: tell an endocrine gland from an exocrine one. Two: name the gland roots and say where each gland sits. Three: tell glyc from gluc, and name the four substance forms. Four: say what a hormone is and what homeostasis names. Five: build and reverse a term, and separate the two diabetes conditions.

Eight combining forms open the unit, and the first two are a contrast rather than a list. Endocrine glands release inward, into the blood. Exocrine glands release outward, through a duct. After that the roots name particular glands, and four of them are placed in the body by a prefix already taught rather than by anything new: endo, para, supra, and hypo.

The system, and its form.

MedTerm 0851 endocrin/o: Endocrine

The combining form endocrin slash o names the endocrine system, whose glands release hormones directly into the bloodstream. Endocrinology is the study of these glands. The Unit Three prefix endo, meaning within, carries the whole definition: endocrine glands release into the blood, and other glands release through ducts.

The other kind of gland.

MedTerm 0852 exocrin/o: Exocrine

The combining form exocrin slash o names glands releasing their secretions through ducts to a surface. Sweat glands are exocrine glands. Endo releases inward to the blood; exo releases outward through a duct. The two terms differ by prefix alone, and that prefix is the entire distinction.

The general form for a gland.

MedTerm 0853 aden/o: Gland

The combining form aden slash o names a gland. An adenoma is a tumour of glandular tissue. Aden slash o names a gland in general, while lymphaden slash o, carried forward from the lymphatic unit, names a lymph node specifically. The added element narrows which structure is meant.

The gland in the neck.

MedTerm 0854 thyr/o: Thyroid

The combining forms thyr slash o and thyroid slash o name the thyroid gland in the neck. Thyroidectomy is surgical removal of the thyroid gland, on the suffix ectomy from Unit Two. The gland's name comes from its shield-like shape, not from anything it does.

The glands beside it.

MedTerm 0855 parathyroid/o: Parathyroid

The combining form parathyroid slash o names the parathyroid glands, lying beside the thyroid. There are usually four of them. The prefix para, from Unit Three, places these beside the thyroid — and they are separate glands with separate functions, not a part of the gland they sit against.

The glands above the kidneys.

MedTerm 0856 adren/o: Adrenal Gland

The combining forms adren slash o and adrenal slash o name the adrenal glands, sitting above the kidneys. They are also named the suprarenal glands, on the Unit Three prefix supra. Adren and suprarenal name one pair of glands, one from Greek habit and one from Latin.

The pituitary, and a misleading prefix.

MedTerm 0857 hypophys/o: Pituitary

The combining form hypophys slash o names the pituitary gland, lying below the hypothalamus — thalam slash o being the Unit Twelve root carried forward here. The pituitary is also named the hypophysis. The prefix hypo in this term names position below, not a deficiency.

The glands belonging to two systems.

MedTerm 0858 gonad/o: Gonads

The combining form gonad slash o names the gonads, the reproductive glands producing sex hormones. The ovaries and testes are gonads. Because they serve both the reproductive and the endocrine systems, their terms appear in two units — orchi slash o and ovari slash o were taught in Unit Eleven.

Six more combining forms, and these name substances rather than structures. Two of them make the closest pair in the unit — glyc and gluc, sugar in general and glucose in particular — and both are in current use, so neither can be treated as a misspelling of the other. A third breaks the unit's only small irregularity, taking an i where every other form here takes an o.

Sugar, in general.

MedTerm 0859 glyc/o: Sugar

The combining form glyc slash o names sugar. Hypoglycemia is a condition of low blood sugar. The g of glyc is hard, so the term opens with a g sound — a pronunciation the book states outright, because the spelling invites the softer one and the softer one is wrong.

Glucose, in particular.

MedTerm 0860 gluc/o: Glucose

The combining form gluc slash o names glucose, the specific sugar circulating in the blood. Glucosuria is the presence of glucose in the urine, on the suffix uria from the urinary unit. Glyc names sugar generally; gluc names glucose. Both appear in current terms.

The hormone regulating it.

MedTerm 0861 insulin/o: Insulin

The combining form insulin slash o names insulin, the hormone regulating blood glucose. Hyperinsulinism is a condition of excessive insulin. Insulin is a hormone, and the pancreas is the gland producing it — pancreat slash o, from the digestive unit, names that gland.

Calcium.

MedTerm 0862 calc/o: Calcium

The combining form calc slash o names calcium. Hypercalcemia is an excess of calcium in the blood, on the suffix emia from Unit Two. The parathyroid glands govern calcium, which is why the gland root from the previous topic and this substance root appear together.

Potassium, and one irregularity.

MedTerm 0863 kal/i: Potassium

The combining form kal slash i names potassium. Hypokalemia is a deficiency of potassium in the blood, again on emia. This form takes an i rather than the usual o as its combining vowel, and that is the one place an otherwise regular unit departs from its own habit.

Sodium.

MedTerm 0864 natr/o: Sodium

The combining form natr slash o names sodium. Hyponatremia is a deficiency of sodium in the blood. Kal is potassium and natr is sodium, taken from the Latin names of both elements — which is why neither root resembles the English word for the element it names.

Two suffixes, and they are the only new ones the unit contributes. One has already been used twice without being named — crine is what endocrine and exocrine are built on. The other, tropin, names a hormone whose work is to start another gland working, so a tropin always names a step in a sequence rather than an end of one.

The suffix already in use.

MedTerm 0865 -crine: To Secrete

The suffix crine names secretion, the release of a substance from a gland. Endocrine and exocrine both take this suffix with opposite prefixes. Crine names the act of releasing, not the substance released — whatever is released carries its own name, and the suffix does not supply it.

A hormone that acts on a gland.

MedTerm 0866 -tropin: Stimulating Hormone

The suffix tropin names a hormone that stimulates the gland its root identifies. Thyrotropin is the hormone stimulating the thyroid gland. A tropin acts on a gland, and the gland it acts on then releases its own hormone, so the term names one link in a chain.

Two entries define the system rather than any part of it. The first says what a hormone is, and the definition turns on distance: a gland releases it in one place and it acts in another. The second names what all that releasing is for, and it is built on a suffix from the cardiovascular unit rather than from the universal block.

What a hormone is.

MedTerm 0867 A Hormone

A hormone is a chemical messenger released by a gland and carried in the blood to act on a distant target. Insulin is a hormone released by the pancreas. A hormone acts at a distance, and acting at a distance is what separates endocrine action from local action.

What the system holds.

MedTerm 0868 Homeostasis

Homeostasis is the maintenance of a stable internal state despite changes outside the body. The root homeo names sameness, and the suffix stasis names holding steady — stasis carried forward from the cardiovascular unit, where it names the stopping of bleeding. Homeostasis names the maintaining, not any one measurement being maintained.

Four pathology terms arriving as two pairs, and within each pair only the prefix changes. Hyper and hypo were taught in Unit Three as an abstract opposition. Here they arrive attached to terms met in one sitting, which is what makes the pattern visible at all. The book flags this run as the strongest argument in the course for teaching word parts inside a system rather than ahead of one.

Sugar above range.

MedTerm 0869 Hyperglycemia

Hyperglycemia is a condition of blood glucose above the normal range. The prefix hyper, the root glyc and the suffix emia build the term directly, with nothing irregular in the join. The entry names a term and stops: ranges, readings, and what follows from them belong to clinical training.

The same term, reversed.

MedTerm 0870 Hypoglycemia

Hypoglycemia is a condition of blood glucose below the normal range. Only the prefix changes between this term and its opposite. Hyper and hypo reverse the finding while the root and the suffix stay identical, which is the mechanism the whole unit exists to demonstrate.

The gland, overactive.

MedTerm 0871 Hyperthyroidism

Hyperthyroidism is a condition of excessive thyroid gland activity. The prefix hyper, the root thyroid and the suffix ism build the term. The suffix ism names the condition of the gland's activity, not the gland itself, so the term describes a state rather than a structure.

The gland, underactive.

MedTerm 0872 Hypothyroidism

Hypothyroidism is a condition of deficient thyroid gland activity. Only the prefix changes between this term and its opposite. The hyper and hypo pattern runs through the whole endocrine unit, and once it is recognised in one pair it does not have to be learned again in the next.

Two entries, numbered adjacently, each pointing at the other. They share the word diabetes and have nothing else in common. What separates them is a Latin word describing urine — honeyed in one case, tasteless in the other — a naming habit older than any measurement, and still the thing that carries the distinction.

The one about glucose.

MedTerm 0873 Diabetes Mellitus

Diabetes mellitus is a condition in which the body cannot regulate blood glucose normally. Mellitus comes from the Latin for honeyed, describing sugar in the urine. A second condition shares the name diabetes and has nothing to do with glucose, so the first word alone never settles which is meant.

The one that is not.

MedTerm 0874 Diabetes Insipidus

Diabetes insipidus is a condition of excessive urine production caused by a hormone imbalance, unrelated to blood glucose. Insipidus comes from the Latin for tasteless, in contrast with mellitus. Two conditions share the word diabetes, and the second word carries the whole distinction.

Two entries close the unit and neither introduces a new word part. The first states outright the rule the preceding twenty-four entries have been demonstrating, then applies it four times. The second decodes twelve terms suffix first, using the three-step method from Unit One and word parts drawn from Units Two through Thirteen.

The rule, stated in the open.

MedTerm 0875 Building Endocrine Terms

Endocrine terms are built more regularly than most: a prefix of direction, a root naming a substance or a gland, and a condition suffix combine without exception. The entry applies that four times — hyperglycemia, hypocalcemia, hyperkalemia, hypothyroidism. Change the prefix and the finding reverses. Change the root and the substance changes. Change the suffix and the kind of term changes. The regularity is the point of the unit: learn one pattern and the terms build themselves.

The capstone. Twelve terms, decoded.

MedTerm 0876 Capstone: Twelve Endocrine Terms Decoded

Twelve terms decoded suffix first. Endocrinology and adenopathy on logy and pathy, adenoma on oma, thyroidectomy on ectomy. Then the run the unit exists for: hyperthyroidism and hypothyroidism on ism; hyperglycemia, hypoglycemia, hypercalcemia, hypokalemia and hyponatremia on emia; and glucosuria on uria. Eight of the twelve are built from one prefix pair and one suffix, which is what makes this the most regular unit in the course. Every suffix used here was taught in Unit Two, and the roots are this unit's own.

Five things to carry out of Unit Thirteen. Endocrine glands release inward, into the blood. Exocrine glands release outward, through a duct to a surface. Both words are built on the suffix crine, which names the act of releasing and not the substance released. Aden slash o names a gland in general, and lymphaden slash o narrows it to a node. The gland roots are thyr and thyroid for the thyroid, parathyroid for the four glands beside it, adren for the adrenals above the kidneys, hypophys for the pituitary below the hypothalamus, and gonad for the ovaries and testes. Four of those are placed by a prefix from Unit Three, and in hypophys that prefix names a position rather than a deficiency. Glyc names sugar in general and gluc names glucose in particular. Both are current and neither is a variant of the other. Insulin slash o names the hormone and pancreat slash o names the gland producing it. Calc, kal and natr name calcium, potassium and sodium, and kal takes an i where the others take an o. A hormone is a chemical messenger released by a gland and carried in the blood to act on a distant target, and acting at a distance is what separates endocrine action from local action. A tropin stimulates the gland its root identifies. Homeostasis names the maintaining of a stable internal state, not any one measurement being maintained. Hyper and hypo reverse the finding and leave the root and the suffix alone: hyperglycemia against hypoglycemia, hyperthyroidism against hypothyroidism. Eight of the capstone's twelve terms are built from that one prefix pair and one suffix. And diabetes on its own settles nothing — mellitus concerns glucose and insipidus does not. Unit Fourteen turns to oncology, radiology and pharmacology, three fields sharing one unit because each contributes vocabulary used across every body system.