Hormones

Chapter 11.1

Insulin

What stimulates insulin release, where does insulin go, and what does it do?

• Stimulus: Increased blood glucose, nutrients, and parasympathetic activity

• Target: Liver, skeletal muscle, and adipose tissue

• Function: Lowers blood glucose by increasing glucose uptake and storage

Glucagon

What stimulates glucagon release, where does it go, and what does it do?

• Stimulus: Low blood glucose, fasting, and sympathetic activity

• Target: Mainly the liver

• Function: Raises blood glucose by promoting glucose release and production

ADH

What stimulates ADH release, where does it go, and what does it do?

• Made by: Hypothalamus

• Released by: Posterior pituitary

• Stimulus: Increased blood osmolarity or decreased blood volume/pressure

• Target: Kidneys and blood vessels

• Function: Increases water reabsorption and can increase blood pressure

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Oxytocin

What stimulates oxytocin release, where does it go, and what does it do?

• Made by: Hypothalamus

• Released by: Posterior pituitary

• Stimulus: Cervical stretching during labor and nipple stimulation

• Target: Uterus and mammary glands

• Function: Stimulates uterine contractions and milk ejection

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TSH

What stimulates TSH release, where does it go, and what does it do?

• Source: Anterior pituitary

• Stimulus: TRH from the hypothalamus

• Target: Thyroid gland

• Function: Stimulates thyroid hormone production, iodine uptake, and thyroid growth

Thyroid hormones: T3 and T4

What stimulates T3 and T4 release, where do they go, and what do they do?

• Source: Thyroid follicular cells

• Stimulus: TSH

• Target: Most body tissues

• Function: Increase metabolic rate, heat production, growth, and development

• Important: T4 is converted to the more potent T3 in target tissues

PTH

What stimulates PTH release, where does it go, and what does it do?

• Source: Parathyroid glands

• Stimulus: Low blood calcium

• Target: Bone, kidneys, and indirectly the intestines

• Function: Raises blood calcium and stimulates activation of vitamin

Calcitonin

What stimulates calcitonin release, where does it go, and what does it do?

• Source: Thyroid gland

• Stimulus: High blood calcium

• Target: Bone and kidneys

• Function: Helps lower blood calcium

Epinephrine

What stimulates epinephrine release, where does it go, and what does it do?

• Source: Adrenal medulla

• Stimulus: Sympathetic preganglionic neurons during stress or danger

• Target: Heart, blood vessels, lungs, liver, and skeletal muscle

• Function: Produces the fight-or-flight response

Aldosterone

What stimulates aldosterone release, where does it go, and what does it do?

• Source: Adrenal cortex

• Stimulus: Angiotensin II and high blood potassium

• Target: Kidneys

• Function: Increases sodium reabsorption and potassium secretion; helps increase blood volume and pressure

Cortisol

What stimulates cortisol release, where does it go, and what does it do?

• Source: Adrenal cortex

• Stimulus: ACTH, especially during stress

• Target: Many tissues throughout the body

• Function: Regulates metabolism, supports stress responses, and affects immune activity

GH

What stimulates growth hormone release, where does it go, and what does it do?

• Source: Anterior pituitary

• Stimulus: GHRH, sleep, exercise, and low blood glucose

• Target: Liver, bone, muscle, and other tissues

• Function: Promotes growth and stimulates the liver to produce IGF-1

IGF-1

What stimulates IGF-1 release, where does it go, and what does it do?

• Source: Mainly the liver

• Stimulus: Growth hormone

• Target: Bones and other tissues

• Function: Promotes growth, especially of bones and other tissues

ACTH

What stimulates ACTH release, where does it go, and what does it do?

• Source: Anterior pituitary

• Stimulus: CRH from the hypothalamus and stress

• Target: Adrenal cortex

• Function: Stimulates cortisol and adrenal androgen secretion

FSH

What stimulates FSH release, where does it go, and what does it do?

Back:

• Source: Anterior pituitary

• Stimulus: GnRH from the hypothalamus

• Target: Ovaries or testes

• Function: Promotes ovarian follicle development and sperm production

LH

What stimulates LH release, where does it go, and what does it do?

Back:

• Source: Anterior pituitary

• Stimulus: GnRH from the hypothalamus

• Target: Ovaries or testes

• Function: Triggers ovulation and stimulates estrogen, progesterone, and testosterone production

Prolactin

What stimulates prolactin release, where does it go, and what does it do?

• Source: Anterior pituitary

• Stimulus: Nipple stimulation and decreased dopamine inhibition

• Target: Mammary glands

• Function: Stimulates milk production

Melatonin

What stimulates melatonin release, where does it go, and what does it do?

• Source: Pineal gland

• Stimulus: Darkness

• Target: Brain and other tissues

• Function: Helps regulate circadian rhythms and the sleep-wake cycle

Estrogen

What stimulates estrogen release, where does it go, and what does it do?

• Source: Ovaries

• Stimulus: FSH and LH

• Target: Reproductive organs, bones, breasts, and brain

• Function: Regulates female reproductive development and menstrual cycles

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Progesterone

What stimulates progesterone release, where does it go, and what does it do?

• Source: Ovaries, especially the corpus luteum

• Stimulus: LH and changes during the menstrual cycle

• Target: Uterus and mammary glands

• Function: Prepares and maintains the uterus for pregnancy

Testosterone

What stimulates testosterone release, where does it go, and what does it do?

• Source: Testes

• Stimulus: LH

• Target: Reproductive organs, muscle, bone, and brain

• Function: Supports sperm production, male reproductive development, and secondary sex characteristics

Erythropoietin

What stimulates erythropoietin release, where does it go, and what does it do?

• Source: Kidneys

• Stimulus: Low oxygen levels in the blood

• Target: Bone marrow

• Function: Stimulates red blood cell production

Active vitamin D

What stimulates active vitamin D production, where does it go, and what does it do?

• Source: Kidneys

• Stimulus: PTH, low blood calcium, and low phosphate

• Target: Intestines, bones, and kidneys

• Function: Increases calcium absorption and helps regulate blood calcium

ANP

What stimulates ANP release, where does it go, and what does it do?

• Source: Heart atrial cells

• Stimulus: Stretch caused by increased blood volume

• Target: Kidneys, blood vessels, and adrenal glands

• Function: Promotes sodium and water loss and lowers blood volume and pressure

Leptin

What stimulates leptin release, where does it go, and what does it do?

• Source: Adipose tissue

• Stimulus: Increased fat stores

• Target: Hypothalamus

• Function: Decreases appetite and helps regulate energy balance

Gastrin

What stimulates gastrin release, where does it go, and what does it do?

• Source: Stomach

• Stimulus: Food, stomach stretching, and peptides

• Target: Stomach glands

• Function: Increases stomach acid secretion and stomach activity

Secretin

What stimulates secretin release, where does it go, and what does it do?

• Source: Small intestine

• Stimulus: Acidic chyme entering the small intestine

• Target: Pancreas and liver

• Function: Stimulates bicarbonate release and helps neutralize stomach acid

CCK

What stimulates CCK release, where does it go, and what does it do?

• Source: Small intestine

• Stimulus: Fatty acids and amino acids

• Target: Pancreas, gallbladder, and stomach

• Function: Stimulates pancreatic digestive enzymes, gallbladder contraction, and slows stomach emptying

GLP-1

What stimulates GLP-1 release, where does it go, and what does it do?

• Source: Small intestine

• Stimulus: Nutrients entering the intestine

• Target: Pancreas, stomach, and brain

• Function: Increases insulin release, decreases glucagon release, slows stomach emptying, and helps reduce appetite