module 7: endocrine system

hormones

chemical signals that travel through the blood stream

Signal transduction

the process by which cells receive and respond to hormones and other signaling molecules from distant organs

signal amplification

the process of increasing the intensity of a signal from a hormone through intracellular reactions

structure of amino acid

• Single amino acid with modification

• Peptide

• Protein

Endocrine/signaling/secretory cell

release horomones

target cell

a specific cell that has receptors for a particular hormone, allowing it to respond to that hormone when it binds to the receptor

Water-soluble horomones

released by exocytosis

exocytosis

a cellular process where a cell releases substances from its interior by fusing vesicles containing those substances with the cell membrane

Lipid-soluble hormones

released by diffusion

signal transduction

When the signaling molecule binds the receptor it changes the receptor protein in some way.

cAMP

key component of intracellular signaling pathways; a molecule that helps regulate many cellular processes, including metabolism, gene regulation, and immune function.

cAMP typically activates

protein kinases cascade

what is a protein kinases cascade

a signaling pathway where a signal is transmitted from one protein to another through a series of sequential phosphorylations, where one protein kinase activates another by adding phosphate groups

Endocrine signaling

a form of cell communication where hormone-producing cells release hormones into the bloodstream to reach distant target cells, triggering a response

thyroid gland

secrete thyroid hormone (t3 and t4) stimulates and maintains metabolic processes; lowers blood calcium levels

parathyroid glands

produce parathyroid hormones (PTH) raises blood calcium levels

adrenal gland: adrenal medulla

epinephrine and norepinephrine; raise blood glucose level, increase metabolic activity, constrict or dilate blood vessels

adrenal glands: adrenal cortex

glucocorticoids; raise blood glucose level, control inflammation

mineralocorticoids: promote reabsorption of Na+ and excretion of K+ in kidneys

ovaries (females)

estrogen, stimulates uterine lining growth, promote development and maintenance of female secondary sex characteristics

progesterone, promotes uterine lining growth

testes (males)

androgens: support sperm formation, promote development and maintenance of male secondary sex characteristics

pineal gland

melatonin: participates in regulation of biological rhythms

hypothalamus

secretes hormones that stimulate or suppress the release of hormones in the pituitary gland, in addition to controlling water balance, sleep, temperature, appetite, and blood pressure

pituitary gland controls the ___

posterior pituitary gland and anterior pituitary gland

posterior pituitary gland

oxytocin: stimulates contraction of uterus and mammary gland cells, modulates behavior,

Vasopressin, also called antidiuretic hormone, promotes retention of water by kidneys, modulates behavior

anterior pitutary

produces and releases hormones regulating growth, metabolism, reproduction, and stress responses

follicle-stimulating hormone (FSH) and luteinizing hormone (LH)

stimulate gonads (ovaries or testes)

thyroid- stimulating hormone (TSH)

stimulates thyroid gland

adrenocorticotropic hormone (ACTH)

stimulates adrenal cortex

prolactin

stimulates mammary gland growth and milk synthesis in mammals

growth hormone (GH)

stimulates growth and metabolic functions

melanocyte-stimulating hormone (MSH)

affects color of melanocytes, a type of skin cell

pancreas

insulin: lowers blood glucose level

glucagon: raises blood glucose level

positive feedback loop

hormone release creates more hormone (ex. oxytocin during childbirth)

negative feedback loop

hormone release returns system to set point (homeostasis)

the hypothalamus is anatomically and functionally related to the

pituitary gland, a bean- sized organ suspended from a stem called the

infundibulum

what kind of tissue is the posterior pituitary made of?

neural tissue

what kind of tissue is the anterior pituitary made of?

glandular tissue

the posterior pituitary does not

produce any hormones; it stores and secretes

hormones produced by the hypothalamus

oxytocin structure

peptide

what gland is oxytocin released from?

released from the posterior pituitary gland

when is oxytocin released?

during childbirth to stimulate contraction of smooth muscle cells in the uterus

Antidiuretic hormone structure

peptide

what gland is Antidiuretic hormone released from?

released from posterior pituitary gland

when is Antidiuretic hormone released?

in response to high blood osmolarity (high solute concentration)

• Increase permeability to water to increase water reabsorption in kidney

• Constrict blood vessels to increase blood pressure

what inhibits antidiuretic hormones?

alcohol, which leads to dehydration

the anterior pituitary gland secretes ____

tropic hormones

tropic hormones

hormones that have other endocrine glands as their target

Thyrotropin-stimulating hormone structure

peptide

what gland is Thyrotropin-stimulating hormone released from?

anterior pituitary

what is Thyrotropin-stimulating hormone stimulated by?

TRH

what does the Thyrotropin-stimulating hormone do?

stimulates release of thyroid hormones by thyroid gland

thyroid hormones (T3 and T4) structure

dipeptide (lipid soluble); contain iodine

thyroid hormones (T3 and T4) function

Increase metabolic rate, cellular respiration, protein synthesis, growth and development, increase

sensitivity to epinephrine

Hypothyroidism

Low metabolism, lethargy

• May have goiter

▪ Enlarged thyroid with non- functional hormones due to lack of iodine

hyperthyroidism

Grave’s disease

• Antibodies mimic TSH

• Increase T3 and T4

• Increased metabolism, sweating, weight loss

calcitonin structure

peptide

what gland is calcitonin released from?

released from the thyroid gland

what is calcitonin related in response to?

rise in blood calcium

• Inhibits osteoclasts (eat bone)

• Stimulates osteoblasts (build bone)

• Decrease calcium absorption in intestines

• Increase calcium loss in urine

Parathyroid hormone structure

peptide

what gland releases Parathyroid hormone?

parathyroid

when is the Parathyroid hormone released?

Released in response to low blood Ca2+

• Stimulates osteoclasts

• Inhibits osteoblasts

• Reabsorption of calcium in kidneys

• Initiates production of calcitriol

(vitamin D3)

▪ Absorption of calcium by intestines

Hyperparathyroidism

• Excess bone resorption

▪ Osteoporosis

• Increased blood calcium

▪ Kidney stones

Hypoparathyroidism

Hypocalcemia (low blood Ca2+)

▪ Muscle twitching, cramps, paralysis

what is the structure of the growth hormone?

peptide

what gland releases the growth hormone?

anterior pituitary gland

what regulates the growth hormone?

GHRH and GHIH (released by hypothalamus)

what does the growth hormone target?

bone, skeletal muscle, adipose tissue, and liver

giantism

a dysfunction of the growth hormone, causes excessive growth and height due to an overproduction of growth hormone (GH) during childhood

acromegaly

a dysfunction of the growth hormone, characterized by the excessive production of growth hormone (GH) after the growth plates have closed in face, hands, or feet

dwarfism

dysfunction of the growth hormone, where there is deficient GH or T3 and T4 and causes short stature that results from a genetic or medical condition.

Achondroplasia

a genetic disorder that affects bone growth, resulting in short stature and disproportionate short limbs; there is an increase in a protein that inhibits bone development

Adrenocorticotropic hormones (ACTH) structure

peptide

what gland releases the Adrenocorticotropic hormones (ACTH)

anterior pituitary; stimulates adrenal glands

adrenal glands

one of the highest rates of blood flow in the body

have structures called outer cortex and inner medulla

Mineralocorticoids

released by adrenal cortex, regulate salt balance and

blood pressure (aldosterone)

Glucocorticoids, including cortisol

released by adrenal cortex, breakdown stored energy molecules; released when fasting

sex steroids

released by adrenal cortex precursors of testosterone and estrogen

Epinephrine (adrenaline) and norepinephrine are released by what gland?

adrenal medulla

what is the structure of Epinephrine (adrenaline) and norepinephrine

peptide

what is the function of Epinephrine (adrenaline) and norepinephrine

play a vital role in the body's "fight-or-flight" response, preparing the body for stress or danger by increasing heart rate, blood pressure, and glucose levels, and dilating airways and pupils

Gonadotropins

hormones produced by the anterior pituitary gland that stimulate the gonads

Gonadotropin-releasing hormone (GnRH) is released from what gland?

the hypothalamus; initiates puberty by triggering release of follicle-

stimulating hormone (FSH) and luteinizing hormone (LH) which

target gonads (ovaries and testes)

FSH structure

peptide

what gland is FSH released from?

anterior pituitary

what is the function of FSH?

Stimulates production and maturation of gametes (egg and sperm)

LH structure

peptide

what gland is LH released from?

anterior pituitary

what is the function of LH?

• Triggers ovulation

• Produces estrogen, progesterone, and testosterone

prolactin structure

peptide

what gland is prolactin released from?

anterior pituitary

what is the function of prolactin?

• Contributes to development of mammary glands and stimulates milk production

• Works with other hormones: estrogen, progesterone, and oxytocin

Pituitary tumors can cause _____

milk production (bc of overproduction of prolactin), infertility, impotence, and gynecomastia (development of breast

tissue)

Melanocyte-stimulating hormone structure

peptide

what gland releases Melanocyte-stimulating hormone?

pituitary (cells on the border between anterior and posterior, pars intermedia)

what is the function of Melanocyte-stimulating hormone?

• Stimulates melanin production in melanocytes

• Increased activity during pregnancy

• Causes darkening of areolas and labia