ANAPHY - CHAPTER 10 ENDOCRINE SYSTEM

ENDOCRINE SYSTEM

is composed of endocrine glands and specialized endocrine cells located throughout the body

HORMONES

very small amounts of chemical messengers secreted by the endocrine glands and cells into the extracellular fluid

EXOCRINE SYSTEM

have ducts that carry their secretions to the outside of the body, or into a hollow organ, such as the stomach or intestines

ENDOCRINOLOGY

study of endocrine system

CHEMICAL MESSENGERS

allow cells to communicate with each other to regulate body activities

GLAND

is an organ consisting of epithelial cells that specialize in secretion, which is the controlled release of chemicals from a cell

AUTOCRINE CHEMICAL MESSENGERS

stimulates the cell that originally secreted it

PARACRINE CHEMICAL MESSENGERS

act locally on neighboring cells secreted by one cell type into the extracellular fluid and affect surrounding cells

NEUROTRANSMITTERS

secreted by neuron that activate an adjacent cell, whether it is another neuron, a muscle cell, or a glandular cell secreted into a synaptic cleft, rather than into the bloodstream

ENDOCRINE CHEMICAL MESSENGERS

secreted into the bloodstream by certain glands and cells, which together constitute the endocrine system travel through the blood to their target cells

LIPID-SOLUBLE HORMONES

nonpolar, and include steroid hormones, thyroid hormones, and fatty acid derivative hormones such as certain eicosanoids

BINDING PROTEINS

lipid-soluble hormones bind to these to travel in the bloodstream

WATER-SOLUBLE HORMONES

polar molecules; they include protein hormones, peptide hormones, and most amino acid derivative hormones

HUMORAL STIMULI

Molecules and ions in the bloodstream can directly stimulate the release of some hormones.

HUMORAL

refers to body fluids, including blood

NEURAL STIMULI

Following action potentials, neurons release a neurotransmitter into the synapse with the cells that produce the hormone In some cases, the neurotransmitter stimulates the cells to increases hormone secretion

NEUROPEPTIDES

Some neuron secrete chemical messengers directly into the blood when they are stimulated making these chemical messengers hormones

RELEASING HORMONES

a term usually reserved for hormones from the hypothalamus

HORMONAL STIMULI

it occurs when a hormone is secreted, in turn, stimulates the secretion of other hormones

TROPIC HORMONES

hormones from the anterior pituitary gland stimulate the secretion from the hypothalamus and pituitary, which is regulated by hormonal stimuli

INHIBITING HORMONES

hormones from the hypothalamus that prevent the secretion of tropic hormones from the anterior pituitary gland

THYROID HORMONES

can control their own blood vessels by inhibiting their anterior pituitary tropic hormone

NEGATIVE FEEDBACK

the hormone's secretion is inhibited by the hormone itself once blood levels have reached a certain point and there is adequate hormone to activate the target cell

POSITIVE FEEDBACK

some hormones, when stimulated by a tropic hormone, promote the synthesis and secretion of the tropic hormone in addition to stimulating their target cell

RECEPTORS

hormones exert their actions by binding to target cell proteins

RECEPTOR SITE

the portion of each receptor molecule where a hormone binds and the shape and chemical characteristics of each receptor site allow only a specific type of hormone to bind to it

SPECIFICITY

the tendency for each type of hormone to bind to one type of receptor, and not to others

LIPID-SOLUBLE HORMONES

are relatively small and are all non polar; they bind to nuclear receptors which are most often found in the cell nucleus (can also be located in the cytoplasm, but then move to the nucleus when activated)

WATER-SOLUBLE HORMONES

polar molecules and cannot pass through the cell membrane

MEMBRANE-BOUND RECEPTORS

proteins that extend across the cell-membrane, with their hormone-binding sites exposed on the cell membrane's other surface

SECOND MESSENGERS

is produced inside a cell once a hormone or another chemical messenger bind to certain membrane-bound receptors

CYCLIC ADENOSINE MONOPHOSPHATE (cAMP)

is a common second messenger produced when a ligand binds to its receptor.

G PROTEINS

consist of three subunits: alpha (α) beta (β) gamma (γ) are so named because one of the subunits binds to guanine nucleotides

ADENYLATE CYCLASE

an enzyme that converts ATP to cAMP

PROTEIN KINASES

enzymes that regulate the activity of other enzymes can either stimulate or inhibit the activity of other enzyme

PHOSPHODIESTERASE

an enzyme in the cytoplasm that breaks down cAMP to AMP

AMPLIFICATION

a single hormone activates many second messengers, each of which activates enzymes that produce an enormous amount of final product

PITUITARY GLAND

it is a small gland about the size of a pea it is housed in a depression of the sphenoid bone inferior to the hypothalamus of the brain

HYPOTHALAMUS

serves as a control center for the autonomic nervous system as well as the endocrine system

ANTERIOR PITUITARY

is made up of epithelial cells derived from the embryonic oral cavity

POSTERIOR PITUITARY

is an extension of the brain and is composed of neurons

PITUITARY GLAND

body's master gland

HYPOTHALAMIC-PITUITARY PORTAL SYSTEM

the capillary beds and veins that transport the releasing and inhibiting hormones

ANTERIOR PITUITARY

synthesizes hormones, whose secretion is under the control of the hypothalamus

POSTERIOR PITUITARY

is a storage location for two hormones synthesized by special neurons in the hypothalamus

GROWTH HORMONE

stimulates the growth of bones, muscles, and other organs by increasing gene expression

GROWTH HORMONE

also slows protein breakdown during periods of food deprivation and favors lipid breakdown

PITUITARY DWARF

a young person suffering from a deficiency of growth hormone remains small, although normal proportioned

GIANTISM

the person becomes abnormally tall

ACROMEGALY

the facial features and hands become abnormally large

INSULIN-LIKE GROWTH FACTORS (IGFs)

group of protein hormones or somatomedins

THYROID-STIMULATING HORMONE (TSH)

bind to membrane-bound receptors on cells of the thyroid gland and stimulate the secretion of thyroid hormone

ADRENOCORTICOTROPIC HORMONE (ACTH)

binds to membrane-bound receptors on cells of the adrenal cortex

ADRENOCORTICOTROPIC HORMONE (ACTH)

increases the secretion of a hormone from the adrenal cortex called cortisol (also called hydrocortisone)

ADRENOCORTICOTROPIC HORMONE (ACTH)

is required to keep the adrenal cortex from degenerating also bind to melanocytes in the skin and increase skin pigmentation

GONADOTROPINS

bind to membrane-bound receptors on the cells of the gonads (ovaries and testes) regulate growth, development, and functions of the gonads

LUTEINIZING HORMONE (LH)

In females stimulates ovulation promotes secretion of the reproductive hormones, estrogen and progesterone

LUTEINIZING HORMONE (LH)

In males stimulates interstitial cells of the testes to secrete the reproductive hormone testosterone

FOLLICLE-STIMULATING HORMONE (FSH)

stimulates the development of follicles in the ovaries and sperm cells in the testes

PROLACTIN

binds to membrane-bound receptors in cells of the breast, where it helps promote development of the breast during pregnancy and stimulates the production of milk following pregnancy

DOPAMINE

formerly called prolactin-inhibiting hormone

MELANOCYTE-STIMULATING HORMONE (MSH)

binds to membrane-bound receptors on melanocytes and causes them to synthesize melanin

ANTIDIURETIC HORMONE (ADH)

binds to membrane-bound receptors and increases water reabsorption by kidney tubules (this result in less water lost as urine)

ANTIDIURETIC HORMONE (ADH)

also called vasopressin

DIABETES INSIPIDUS

the production of a large amount of dilute urine (lack of ADH secretion)

OXYTOCIN

binds to membrane-bound receptors and causes contraction of the smooth muscle cells of the uterus as well as milk letdown from the breasts in lactating women

PITOCIN

commercial preparations of oxytocin are given under certain conditions to assist in childbirth and to constrict uterine blood vessels following childbirth

THYROID GLAND

synthesizes and secretes three hormones: Triiodothyronine (T3) Thyroxine (tetraiodothyronine; T4) Calcitonin

THYROID GLAND

it is made up of two lobes connected by a narrow band called the isthmus (a constriction)

THYROID GLAND

one of the largest endocrine glands

THYROID FOLLICLES

(thyroid gland) small spheres with walls composed of simple cuboidal epithelium

THYROGLOBULIN

to which thyroid hormones are attached

PARAFOLLICULAR CELLS

between the follicles is a network of loose connective tissue that contains capillaries and scattered C cells, which secrete the hormone calcitonin

THYROXINE

tetraiodothyronine contains four iodine atoms and is abbreviated T4

TRIIODOTHYRONINE

contains three iodine atoms and is abbreviated T3

GOITER

a loss of negative feedback will result in excess TSH thyroid gland to enlarge

HYPOTHYROIDISM

a lack of thyroid hormones

CRETINISM

is characterized by development delay, short stature, and abnormally formed skeletal structure (in infants)

HYPERTHYROIDISM

elevated rate of thyroid hormone secretion

GRAVES DISEASE

is an autoimmune disease that cause hyperthyroidism occurs when the immune system produces abnormal proteins that are similar in structure and function of TSH, which overstimulates the thyroid gland

EXOPHTHALMIA

bulging of the eyes

CALCITONIN

lowers blood Ca2+ levels to return to their normal range

PARATHYROID GLANDS

four tiny glands that are embedded in the posterior wall of the thyroid gland secrete a hormone called parathyroid hormone (PTH)

PARATHYROID HORMONE (PTH)

essential for the regulation of blood calcium levels

HYPERPARATHYROIDISM

an abnormally high rate of PTH secretion

HYPOPARATHYROIDISM

an abnormally low rate of PTH secretion

ADRENAL GLANDS

two small glands located superior to each kidney

ADRENAL MEDULLA

inner part of the adrenal glands that secretes epinephrine and norepinephrine

ALDOSTERONE

is produced in the greatest amounts, although other, closely related mineralocorticoids are also secreted

ADRENAL CORTEX

the outer portion of the adrenal glands

MINERALACORTICOIDS

regulate ion balance in the blood major secretory products of the zona glomerulosa (outer zone)

GLUCOCORTICOIDS

help to provide energy for cells by stimulating the increased use of lipids and proteins secreted in zona fasciculata (middle zone)

ADRENAL ANDROGENS

secreted by zona reticularis stimulate the development of male secondary sex characteristics

PANCREAS ISLETS

which are dispersed throughout the exocrine portion of the pancreas

ACIDOSIS

when blood glucose levels are very low, the breakdown of lipids can cause the release of enough fatty acids and ketones to reduce the pH of the body fluids below normal

INSULIN

elevated blood glucose levels stimulate beta cells to secrete this

SATIETY CENTER

the area of the hypothalamus that controls appetite

DIABETES MELLITUS

is the body's inability to regulate blood glucose levels within the normal range

TYPE 1 DIABETES MELLITUS

occurs when too little insulin is secreted from the pancreas

TYPE 2 DIABETES MELLITUS

caused by either too few insulin receptors on target cells or defective receptors on target cells