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Adrenal Glands

Two glands that sit on top of kidneys

Divided into two areas:

Cortex – outer glandular region in three layers

Medulla – inner neural tissue region

Cortex produces three major groups of steroid hormones collectively called corticosteroids

Produce over 50 different hormones themselves

Mineralocorticoids (mainly aldosterone)

Produced in outer adrenal cortex

Regulate mineral content in blood, water, and electrolyte balance (target organ is kidney)

Production stimulated by renin (produced in kidneys) and aldosterone

Production inhibited by atrial natriuretic peptide (produced by heart)

Glucocorticoids (including cortisone and cortisol)

Produced in middle layer of adrenal cortex

Promote normal cell metabolism

Help resist long-term stressors (work, family, health stress)

Released in response to increased blood levels of ACTH

Sex hormones

Produced in inner layer of adrenal cortex

Androgens (male) and some estrogen (female)​​​​​​​​​​​​​​

Two hormones produced by medulla called catecholamines which are triggered by sympathetic nervous system

Epinephrine (adrenaline)

Norepinephrine (noradrenaline)

prepare the body to deal with short-term stress as in fight-or-flight scenarios

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Pancreas (Pancreatic Islets)

the pancreas is a mixed gland

Islets of Langerhans in pancreas produce hormones

Insulin (from beta cells) – allows glucose to cross plasma membranes into cells

Blood glucose now delivered to cells for energy

Glucagon (from alpha cells) – allows glucose to enter blood

Converts stored glucose (glycogen) back into glucose

these hormones are antagonists that maintain blood sugar homeostasis

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Also produce progesterone

Produced by corpus luteum

Acts with estrogen to bring about menstrual cycle

Helps in implantation of an embryo in uterus

Pineal Gland

Found on third ventricle of brain

Secretes melatonin

Helps establish body’s wake/sleep cycles

May have other as-yet-unsubstantiated functions

Thymus

Located posterior to sternum

Largest in infants and children

Produces thymosin that

Matures & activates lymphocytes (WBC) in infants & children (other organs produce WBC during adulthood) in immune system

Ovaries

Produce estrogens

Produced by Graafian follicles in ovaries or placenta

Stimulates development of secondary female characteristics

Matures female reproductive organs

Helps prepare uterus to receive a fertilized egg

Helps maintain pregnancy

Prepares breasts to produce milk

Also produce progesterone

Produced by corpus luteum

Acts with estrogen to bring about menstrual cycle

Helps in implantation of an embryo in uterus

Testes

​​​​​​​Interstitial cells of testes are hormone-producing

Produce several androgens

Testosterone is the most important androgen

Placenta

Produces hormones that maintain pregnancy

Some hormones play a part in baby delivery

Produces human chorionic gonadotropin (hCG) in addition to estrogen, progesterone, and other hormones

Home pregnancy tests check for presence of hCG

Duodenum (first part) of small intestine

Gastrin – delivered to stomach to inhibit HCl

Secretin – stimulates pancreas to release high pH juice; stimulates release of bile from liver

Cholecystokinin (CCK) – stimulates pancreas to release enzymes; gallbladder to release stored bile

Stomach

Gastrin – stimulates stomach glands to release HCl

Adipose tissue

Leptin​​​​​​​ – stimulates brain to suppress appetite & increase energy usage​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​