study guide chapters 18-20

Endocrine glands

-Secrete chemical substances called, hormones.

-Ductless glands; secrete hormones directly into the blood & not into ducts.

Hormones

-Chemical messenger that influences/controls the activities of other tissues or organs

islets contain

secreting cells

Gonads produce

gametes (oocytes and sperm respectively)

gonads are

ovaries and testes

ovaries produce

• two estrogens (estradiol and estrone), progesterone, relaxin, and inhibin

Testes produce

• testosterone

Melatonin helps to

• regulate the body's biological clock

The thymus is located

behind the sternum between the lungs

thumus produces

thymosin, thymic humoral factor (THF), thymic factor (TF), and thymopoietin

• These hormones promote maturation of the immune system's T cells

function of hormones

Help regulate metabolic processes involving carbohydrates, proteins, & fats

-Help in growth & reproduction

-Help regulate water & electrolyte balance

-Help your body meet the demands of infection, trauma, & stress

Exocrine glands secrete their products into what

ducts

The posterior pituitary gland does not synthesize any
hormones

it stores and releases from axon terminals

what 2 hormones are produced by the neurosecretory cells of the hypothalamus:

Oxytocin (OT)
Antidiuretic hormone (ADH)

Axons from the neurosecretory cells form

the hypothalamohypophyseal tract

The amount of antidiuretic hormone (ADH) secreted
varies

with blood osmotic pressure

An increase in blood volume

causes a decrease in ADH secretion

A decrease in blood volume

causes an increase in ADH secretion

ADH decreases

urine output

osmoreceptors in the hypothalamus monitor

blood osmotic pressure

The thyroid gland is a butterfly- shaped gland

located inferior to the larynx and anterior to the trachea

It has right and left lateral lobes

connected by an isthmus

Some glands also have a pyramidal lobe projecting from

the isthmus

exocrine glands do not include any

hormones

Thyroid hormones:

• Increase basal metabolic rate (BMR)

• Help maintain normal body temperature

• Stimulate protein synthesis

• Increase the use of glucose and fatty acids for ATP
  production

• Upregulate beta (β) receptors that attach to
  catecholamines

• Work with hGH and insulin to accelerate body growth

Parathyroid glands contain 2
types of cells:

chief cells and oxyphil cells

• Chief cells (principal cells

produce parathyroidhormone (PTH, parathormone)

Oxyphil cells

secrete excess PTH in cases of parathyroid cancer

suprarenal glands are covered by

a connective tissue capsule

The glands are divided into two regions:

The outer cortex

The inner medulla

Testosterone Inhibits secretion

of FSH from anterior pituitary.

ovarian hormones inhibit

secretion of FSH from anterior pituitary.

The pancreas is located

in the curve of the duodenum

the pancreas is both

an endocrine and exocrine gland

Exocrine glands include

sudoriferous glands, sebaceous glands, mucous glands, digestive glands and several others throughout the body

what glands secrete hormones

endocrine gland

how do endocrine gland secrete their hormones

directly into the interstitial fluid that surrounds them

how do hormones diffuse into the blood

by the capillaries which then carry the hormone to target cell throughout the body

Secretion of glucocorticoids help control:

• Protein breakdown

• Glucose formation

• Lipolysis

• Resistance to stress

• Inflammation

• Immune responses

Almost all of the exocrine cells of the pancreas

are arranged in clusters called acini

Acini produce

• digestive enzymes that are delivered to the gastrointestinal tract through duct

where are islets found

Scattered among the acini

The major androgen secreted by the suprarenal cortex is

dehydroepiandrosterone (DHEA)

In males, after puberty

the hormone testosterone is secreted in much larger quantities so DHEA has virtually no effect

In females, DHEA and other adrenal androgens play a major role in

promoting libido and are converted to estrogens

In menopausal women, all female estrogens come from

adrenal androgens

The adrenal medulla is stimulated by

sympathetic preganglionic neurons of the autonomic nervous system (ANS)

Chromaffin cells secrete

epinephrine (adrenaline) and norepinephrine (noradrenaline)

Endocrine glands include

pituitary, thyroid, parathyroid, adrenal and pineal glands

Certain organs and tissues that are not part of the
endocrine system also secrete hormones because

they contain secreting cells

Secreting cells can be found in

hypothalamus, thymus, pancreas, ovaries, testes, kidneys, stomach, liver, small intestine, skin, heart, adipose tissue and
placenta

• Receptors may be down-regulated

in the presence of high concentrations of hormone

• Receptors may be up-regulated

in the presence of low concentrations of hormone

Hormones that don’t circulate

are local hormones called paracrines

Those that act on the same cell that secretes them

are autocrines.

lipid soluble hormones

steroid hormones, thyroid hormones, nitric oxide

water- soluble hormones

amine hormones, peptide and protein hormones, eicosanoid hormones

Water-soluble hormones circulate

freely in the plasma

Lipid-soluble hormones circulate

by binding to transport proteins

Steroid hormones include

Aldosterone, cortisol, androgens, Calcitriol, Testosterone, Estrogens, progesterone

Calcitriol is the

active form of vitamin D

Aldosterone, cortisol, and androgens is secreted by

Suprarenal cortex.

Calcitriol secreted by

Kidneys

Testosterone is secreted by

Testes

Estrogens, progesterone is secreted by

Ovaries

Thyroid hormones include

T_{3 ,}T₄

T₃ and T₄ are secreted by

thyroid glands

what cells in thryoid gland secrete T₃ T₄

thyrocytes or t cells

Gas hormones include

Nitric oxide (NO), Prostaglandins, leukotrienes.

NO is secreted by

Endothelial cells lining blood vessels.

Prostaglandins, leukotrienes are secreted by

All cells except red blood cells.

Amines hormones include

Epinephrine, norepinephrine (catecholamines), Melatonin, Histamine, Serotonin

Epinephrine, norepinephrine (catecholamines) is secreted by

Suprarenal medulla

Melatonin is secreted by

Pineal gland

Histamine is secreted by

Mast cells in connective tissues

Serotonin is secreted by

Platelets in blood

peptides and proteins include

All hypothalamic releasing and inhibiting hormones, oxytocin, antidiuretic hormone, growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, luteinizing hormone, prolactin, melanocyte-stimulating hormone, insulin, glucagon, somatostatin, pancreatic polypeptide, Parathyroid hormone, calcitonin, gastrin, secretin, cholecystokinin, GIP (glucose- dependent insulinotropic peptide), Erythropoietin, Leptin.

All hypothalamic releasing and inhibiting hormones secreted by

Hypothalamus

Oxytocin, antidiuretic hormone secreted by

Posterior pituitary

Growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, luteinizing hormone, prolactin, melanocyte stimulating hormone secreted

Anterior pituitary

Insulin, glucagon, somatostatin, pancreatic polypeptide secreted by

pancreas

parathyroid hormone is secreted by

parathyroid glands

Calcitonin is secreted by

thyroid gland

what cells secrete calcitonin

thyrocytes specifically C cells

Gastrin, secretin, cholecystokinin, GIP (glucose-dependent insulinotropic peptide) is secreted by

Stomach and Small intestine specifically enteroendocrine cells

Erythropoietin is secreted by

kidneys

Leptin is secreted by

Adipose tissue

what is the basic sex hormone

aldosterone

what happens when a molecule can’t sneak past the membrane

it needs a messenger system to relay the info to the hormone

Responses to the same hormone may vary depending on
the hormone itself and the target cell.

The response may be

• Synthesis of new molecules
• Changing permeability of the cell membrane - in or out of the memb.
• Stimulating transport of a substance into or out of
the cell
• Altering the rate of metabolic actions - how quick or slow you use it
• Causing contraction of smooth or cardiac muscle

target cell responds to a hormone is based on

• The hormone’s concentration in the blood

• The number of hormone receptors on the target cell

• influences exerted by other hormones

• Some hormones work more effectively when a
  second hormone is present to assist them

• Some hormones oppose the action of others

hormones are secreted in

short bursts when needed

hormones are secreted regularly by

signals from NS, chemical changes in blood, other hormones

what is most of the feedback that occurs

negative feedback

what are the positive feedback

childbirth, lactation, and blood clots

withdraw additional hormone when

blood concentration is back to normal

what 2 glands work together to control other endocrine glands

hypothalamus and pituitary glands

adenohypophysis makes up

75% of the pituitary glands weight

how many hormones do adenohypophysis secrete

7

what are the 7 hormones secreted by the adenohypophysis

• Human growth hormone (hGH) - all tissue
• Thyroid-stimulating hormone (TSH) - thyroid gland
• Follicle-stimulating hormone (FSH) - reproductive tissue
• Luteinizing hormone (LH) - reproductive tissue
• Prolactin (PRL) - specific
• Adrenocorticotropic hormone (ACTH) - suprarenal/ adrenal glands
• Melanocyte-stimulating hormone (MSH) - production of melanin