Endocrine System

The Chemistry of Hormones: Chemical substances that are secreted by endocrine cells into the extracellular fluid and regulate the metabolic activity of other cells in the body.

Hormones

The Chemistry of Hormones: The two chemical classifications

Steroids - made from cholesterol
Amino acid-based molecules - made from proteins

The Chemistry of Hormones: Types of Steroidal hormones

Sex & Adrenal hormones

The Chemistry of Hormones: Types of Amino acid-based molecules

All other remaining hormones

Hormone Action: Although the bloodborne hormones circulate to all the organs of the body, a given hormone affects only certain tissue cells or organs, referred to as its...

target cells or target organs

Hormone Action: In order for a target cell to respond, what must be present for it to attach too?

Specific Protein Receptors

Hormone Action: Only when this _______ occurs can the hormone influence the workings of a cell.

binding

Hormone Mechanisms: What are the two mechanisms by which hormones trigger changes in cells?

Direct Gene Activation
Second-Messenger System

Direct Gene Activation: Which two hormones use this mechanism to communicate with their target cells?

Steroidal and Thyroid

Direct Gene Activation: These hormones can enter the target cell and change the cell's...

DNA

Direct Gene Activation: They can enter the cells due to being what kind of hormones?

lipid soluble

Second-Messenger System: Hormones that are unable to enter the target cells because they are...

water-soluble and nonsteroidal

Second-Messenger System: These hormones bind to hormone receptors situated on the target cell's ________ and utilize a second-messenger.

surface

Second-Messenger System: Once bound to the cell receptor on the outside, an __________ is triggered inside the cell which causes a change to occur.

enzyme

Control of Hormone Release: What are the chief means of regulating blood levels of nearly all hormones?

Negative feedback mechanisms

Control of Hormone Release: Some internal or external stimulus triggers hormone secretions; then __________ hormone levels inhibit further hormone release (even while promoting responses in their target cells).

rising

Control of Hormone Release: As a result, blood levels of many hormones vary only within a very...

narrow range

Control of Hormone Release: The Three major categories

Hormonal Stimuli
Humoral Stimuli
Neural Stimuli

Hormonal Stimuli: The most common hormonal stimulus, in which endocrine hormones organs are prodded into by other...

hormones

Hormonal Stimuli: As the hormones produced by the final target glands increase in the blood, they "_________________" to inhibit.

feed back

Humoral Stimuli: Changing __________________ of certain ions and nutrients may also stimulate hormone release.

blood levels

Humoral Stimuli: Hormones released in response to humoral stimuli include __________ by the thyroid gland, and _________ by the pancreas.

Calcitonin, Insulin

Neural Stimuli: In isolated cases, _________________ stimulate hormone release, and the target cells are said to respond to neural stimuli

nerve fibers

The hypothalamic hormones stimulate the anterior pituitary gland to secrete its hormone, and many anterior pituitary hormones stimulate other endocrine organs to release their hormones. What is this example?

Hormonal Stimuli

Decreasing blood calcium levels prompts the release of parathyroid hormone (PTH) by cells of the parathyroid glands. Because PTH acts by several routes to reverse that decline, blood Ca2+ levels soon rise, ending the stimulus for PTH release. What is this example?

Humoral Stimuli

The sympathetic nervous system stimulation of the adrenal glands to release norepinephrine and epinephrine during periods of stress. What is this example?

Neural Stimuli

Endocrine glands: ____________ glands that produce hormones that they release into the blood or lymph.

Ductless

Exocrine glands: Release their products at the body's __________ or into the body cavities through __________.

surface, ducts

List of the Endocrine Organs (Glands)

Pituitary
Thyroid
Parathyroids (4-8)
Adrenals (2)
Pineal
Thymus
Pancreas
Gonads (2)

Pituitary Gland: The size of a...

pea

Pituitary Gland: It hangs by a stalk from the ___________ surface of the __________________ of the brain, where it is snugly surrounded by the Turk's saddle of the sphenoid bone.

inferior, hypothalamus

Pituitary Gland: The two lobes

Anterior pituitary (glandular tissue)
Posterior pituitary (nervous tissue)

Anterior Pituitary: What are the Hormones (FLAT PG)

FSH (Follicle-stimulating hormone)
LH (Luteinizing hormone)
ACTH (Adrenocorticotropic hormone)
TSH (Thyroid-stimulating hormone)

PRL (Prolactin)
GH (Growth Hormone)

Hormones of the Anterior Pituitary: Growth Hormone (GH) -

Stimulates the growth of bones and muscles

Hormones of the Anterior Pituitary: Prolactin (PRL) -

Stimulates milk production

Hormones of the Anterior Pituitary: Follicle-stimulating hormone (FSH) -

Stimulates the production of sex cells

Hormones of the Anterior Pituitary: Luteinizing hormone (LH) -

Stimulates the ovaries & testes

Hormones of the Anterior Pituitary: Thyroid-stimulating hormone (TSH) -

stimulates metabolism & lower Ca2+ in the blood

Hormones of the Anterior Pituitary: Adrenocorticotropic hormone (ACTH) -

Stimulates the adrenal cortex

Hormones of the Posterior Pituitary: Why is the posterior pituitary gland not an endocrine gland?

It does not produce the hormones it releases

Hormones of the Posterior Pituitary: Oxytocin - Stimulates powerful ___________ of the uterine muscle during labor and after birth.

contractions

Hormones of the Posterior Pituitary: Oxytocin - Stimulates the ______________ in nursing women.

let-down reflex

Hormones of the Posterior Pituitary: Antidiuretic Hormone (ADH) - ADH inhibits or prevents...

urine production

Hormones of the Posterior Pituitary: Antidiuretic Hormone (ADH) - It causes the kidneys to reabsorb more water from forming urine; as a result, urine volume

decreases

Hormones of the Posterior Pituitary: Antidiuretic Hormone (ADH) - In large amounts, it...

increase BP

Hormones of the Thyroid Gland: Located at the base of the throat, just inferior to the __________________, where it is easily palpated during a physical examination.

Adam's apple

Hormones of the Thyroid Gland: It has how many lobes?

2

Hormones of the Thyroid Gland: It creates three hormones -

Triiodothyronine (T3)
Thyroxine (T4)
Calcitonin

Hormones of the Thyroid Gland: T3 & T4 - They control the rate at which glucose is "burned," or oxidized, and converted to body heat and chemical energy (_________________)

metabolism

Hormones of the Thyroid Gland: T3 & T4 - What kind of cells are targets of these hormones

Every

Hormones of the Thyroid Gland: Calcitonin - It _______________ blood calcium levels by causing calcium to be deposited in the bones.

decreases

Hormones of the Parathyroid Gland: Tiny masses of glandular tissue found on the __________ surface of the thyroid gland.

posterior

Hormones of the Parathyroid Gland: Typically, how many parathyroid glands are on each thyroid lobe?

2

Hormones of the Parathyroid Gland: Parathyroid Hormone (PTH) - The most important regulator of __________________ ion homeostasis of the blood.

calcium

Hormones of the Parathyroid Gland: Parathyroid Hormone (PTH) - PTH is secreted when Ca2+ is _____. It stimulates bone destruction cells.

low

The Adrenal Glands: Two bean-shaped glands that curve over the...

top of the kidneys

The Adrenal Glands: It is structurally and functionally...

two endocrine organs in one

The Adrenal Glands: The two parts -

Glandular tissue (Cortex)
Neural Tissue (Medulla)

Hormones of the Adrenal Glands: (Cortex) Mineralocorticoids -

Aldosterone promotes sodium reabsorption, and therefore water reabsorption

Hormones of the Adrenal Glands: (Cortex) Glucocorticoids - promote cell metabolism and help the body resist long-term stressors. Other effects include increased blood sugar levels and decreasing the effects of inflammation.

Cortisone & Cortisol

Hormones of the Adrenal Glands: (Cortex) Sex Hormones -

the adrenal glands produce small amounts

Hormones of the Adrenal Glands: (Medulla) - When the medulla is stimulated by sympathetic nervous system neurons, its cells release two similar hormones:

Epinephrine & Norepinephrine

Hormones of the Adrenal Glands: (Medulla) - Epinephrine & Norepinephrine are triggered due to the...

fight or flight response (short-term stressors)

Hormones of the Adrenal Glands: (Medulla) - Epinephrine & Norepinephrine causes...

Increased heart rate
Increased blood pressure
Increased blood glucose levels
Dilates small passageways of the lungs

Hormones of the Pancreas: The pancreas, located close to the stomach in the abdominal cavity, is a mixed gland. It has hidden endocrine glands within known as the ______________________.

Islets of Langerhans

Hormones of the Pancreas: The exocrine part acts as part of the...

digestive system

Hormones of the Pancreas: Two hormones produced -

Insulin
Glucagon

Hormones of the Pancreas: Insulin -

triggered by high glucose levels in the blood

Hormones of the Pancreas: Glucagon -

triggered by low glucose levels in the blood

Hormones of the Pineal Gland: It is a small, cone-shaped gland that hangs from the ____ of the third ventricle of the brain.

roof

Hormones of the Pineal Gland: The endocrine function of this gland is well known. (True or False)

False (It is a mystery)

Hormones of the Pineal Gland: Which hormone appears to be secreted in substantial amounts?

Melatonin

Hormones of the Pineal Gland: The levels of melatonin _____ and _____ during the course of the day and night.

rise, fall

Hormones of the Pineal Gland: Melatonin is believed to be a "______________" that plays an important role in establishing the body's day-night cycle.

sleep trigger

Hormones of the Thymus Gland: The thymus is located in the upper thorax, posterior to the....

sternum

Hormones of the Thymus Gland: Large in infants and children, it ___________ in size throughout adulthood.

decreases

Hormones of the Thymus Gland: The thymus produces a hormone called...

thymosin

Hormones of the Thymus Gland: Thymosin is essential for normal development of...

T lymphocytes and the immune response

Hormones of the Gonads: Estrogen / Progesterone - Produced in the...

ovaries

Hormones of the Gonads: Estrogen / Progesterone - Estrogen is responsible for the development of _________________________ in women and the appearance of secondary sex characteristics.

sex characteristics

Hormones of the Gonads: Estrogen / Progesterone - Together the bring about the...

menstrual cycle

Hormones of the Gonads: Testosterone - Produced in the...

testes

Hormones of the Gonads: Testosterone - It causes the male's secondary...

sex characteristics

Stomach: Gastrin -

Stimulates glands to release hydrochloric acid (HCI)

Kidney: Erythropoietin -

stimulates RBC production

Heart: Atrial Natriuretic Peptide (ANP) -

inhibits the renin-angiotensin-aldosterone system; thereby decreasing blood volume and blood pressure.

Placenta: Human Chorionic Gonadotropin (hCG)

stimulates the production of estrogens and progesterone to maintain pregnancy