Endocrine System II: Inferior Glands
 Adrenal Gland Hormones
• Cortex Hormones
 Aldosterone (mineralocorticoids)
 Cortisol (glucocorticoids)
 Androgens (gonadocorticoids)
• Medulla Hormones
 Epinephrine and Norepinephrine
(catecholamines)
 Pancreas
• Beta cell hormone: insulin
• Alpha cell hormone: glucagon
 Other Endocrine Tissues
• Thymus
• Gonads (Ovaries and Testes)
Endocrine System II: Inferior Glands
 Adrenal Gland Hormones
• Cortex Hormones
 Aldosterone (mineralocorticoids)
 Cortisol (glucocorticoids)
 Androgens (gonadocorticoids)
• Medulla Hormones
 Epinephrine and Norepinephrine
(catecholamines)
 Pancreas
• Beta cell hormone: insulin
• Alpha cell hormone: glucagon
 Other Endocrine Tissues
• Thymus
• Gonads (Ovaries and Testes)
Adrenal (Suprarenal) Glands
 Two parts that act as if
separate glands
• Cortex – outer
glandular region in
three layers
• Medulla – inner
neural tissue region
 Sits on top of the
kidneys
Ad-renal
both mean “upon or
Epi-nephros
next to the kidney”
&
Three Layers of Cortex and the Medula: Four Sources of Hormones
Capsule
Zona
glomerulosa
• Medulla
• Cortex
Medulla
Kidney
Figure 16.13a
Zona
fasciculata
Produces
glucocorticoids like
cortisone and
cortisol
Zona
reticularis
Produces androgens
like estrogens and
testosterone
(gonadocorticoids)
Cortex
Adrenal gland
Produces
mineralocorticoids
like aldosterone
Adrenal
medulla
Produces
catecholoamines like
epinephrine and
norepineprhine
Adrenal
Cortex
Aldosterone
andAldosterone
the Zona Glomerulosa
Type: Steroid hormones, classified as mineralocorticoids, aldosterone
most important of these, made in the zona glomerulosa of adreal
cortex
Regulation: Decreased blood pressure stimulates kidneys to release
renin, triggers formation of angiotensin II stimulating aldosterone
release. Humoral hyponatremia/ hyperkalemia stimuates release.
ACTH release during stress stimulates release. Aldosterone release
inhibited by atrial natururetic peptide (ANP) from heart.
Target: Tubules of the kidney
Action: Stimulates Na+ reabsorption and water retention by the
kidneys, increasing blood pressure; causes secretion of K+ in the urine.
Hypersecretion: Aldosteronism usually from adrenal tumors;
causes hypertension and edema due to excessive Na+ and
excretion of K+ leading to abnormal function of neurons and
muscle
Hyposecretion: Aldosterone insufficiency causes sodium loss,
hyperkalemia, acidosis
Regulation of Blood Volume and Pressure
Regulation of Blood Volume and Pressure
Regulation of Blood Volume and Pressure
Regulation of Blood Volume and Pressure
Glucocorticoids and the Zona Fasciculata
Type: Steroid hormone, classified as glucocorticoids, cortisol most
important of these, made in the zona fasciculata of adreal cortex
Regulation: Released in response to increased blood levels of ACTH
produced by anterior pituitary; patterns of eating and activity, stress
Target: Nearly all cells.
Action: Keeps blood sugar levels relatively constant. Maintains blood
pressure by increasing the action of vasoconstrictors. Promote normal cell
metabolism by causing fat and protein conversion to glucose
(gluconeogenesis - a kind of “reverse glycolysis”). Promotes rise in blood
glucose (a hyperglycemic hormone), fatty acids, amino acids. Help resist
long-term stressors. Decreases edema and pain-producing
prostaglandins.
Hypersecretion: Cushing’s syndrome: Depression of cartilage and bone
formation, reduction of inflammatory response, depression of immune
system; moon face, “buffalo hump” Also seen with ACTH hypersecretion.
Hyposecretion: Addison’s disease (adrenalcortico insufficiency): coupled
with deficits in aldosterone, Decrease in glucose and Na+ levels, weight
loss, severe dehydration, and hypotension. Skin pigmentation. Also seen
with ACTH hyposecretion.
Androgens and the Zona Reticularis
Type: Steroid hormones, classified as gonadocorticoids; mostly
androgens (male sex hormones, converted to testosterone in tissue) or
estrogen in females, made in the zona reticularis of adreal cortex
Regulation: Stimulated by ACTH from hypothalamus; inhibition
mechanism unknown
Target: Urogenital tissue, hair follicles, muscle and bone tissue
Action: Contributes to the onset of puberty, appearance of secondary
sex characteristics, sex drive
Hypersecretion: Virilization (rapid sex development); in children: pubic
hair, acne, body odor, muscle and skeletal growth, precocious puberty
(before 8-9 yrs old); in adults: cessation of menstruation, excessive hair,
masculination
Hyposecretion: Often associated with Addison’s disease (adrenalcortico
insufficiency) since the whole adrenal cortex makes insufficient
hormones.
Steroid Hormones Come From Cholesterol
Endocrine System II: Inferior Glands
 Adrenal Gland Hormones
• Cortex Hormones
 Aldosterone (mineralocorticoids)
 Cortisol (glucocorticoids)
 Androgens (gonadocorticoids)
• Medulla Hormones
 Epinephrine and Norepinephrine
(catecholamines)
 Pancreas
• Beta cell hormone: insulin
• Alpha cell hormone: glucagon
 Other Endocrine Tissues
• Thymus
• Gonads (Ovaries and Testes)
Hormones of the Adrenal Medulla
Type: Catecholamine hormones: epinephrine (80%) and
norepinephrine (20%)
Regulation: Released in response to sympathetic neural stimulation;
inhibited by lack of stimulus
Target: Adrenergic receptors on many different organs and tissues.
Action: Epinephrine stimulates metabolic activities, bronchial dilation,
and blood flow to skeletal muscles and the heart. Norepinephrine
influences peripheral vasoconstriction and blood pressure
Hypersecretion: Prolonged flight or fight response; hypertension
Hyposecretion: Unimportant effects
Adrenal Response to Stress
Endocrine System II: Inferior Glands
 Adrenal Gland Hormones
• Cortex Hormones
 Aldosterone (mineralocorticoids)
 Cortisol (glucocorticoids)
 Androgens (gonadocorticoids)
• Medulla Hormones
 Epinephrine and Norepinephrine
(catecholamines)
 Pancreas
• Beta cell hormone: insulin
• Alpha cell hormone: glucagon
 Other Endocrine Tissues
• Thymus
• Gonads (Ovaries and Testes)
Pancreas: An Exocrine and Endocrine Organ in One
Islet of Lagerhans
Acinar (exocrine cells) make
enzymes for digestion
Insulin and Glucagon
from Beta and Alpha
Islet Cells
Beta Cells of Pancreatic Islets: Insulin
Type: Protein hormone; antagonist of glucagon
Regulation: Direct humoral stimulation, synthesized in islet beta
cells and released in response to high blood glucose
(hyperglycemia).
Target: All cells but especially liver, adipose tissue, muscles
Action: Lowers blood glucose levels by enhancing membrane
transport of glucose into fat and muscle cells. Participates in
neuronal development and learning and memory. Inhibits
glycogenolysis and gluconeogenesis. Hypoglycemic hormone.
Hypersecretion: Hyperinsulinism: Excessive insulin secretion;
results in hypoglycemia, disorientation, unconsciousness
Hyposecretion: Diabetes mellitus (DM) caused by beta cell
hyposecretion (Type I: juvenile) or insulin resistance (Type II: late
onset or adult) associated with polyuria, polydipsia (thirst),
polyphagia (hunger); acetone breath, hyperpnea (heavy
breathing), ketonuria in urine, blood ketoacidosis
Alpha Cells of Pancreatic Islets: Glucagon
Type: Protein hormone; antagonist of insulin
Regulation: Direct humoral stimulation, synthesized in islet alpha
cells and released in response to low blood glucose
(hypoglycemia).
Target: The major target is the liver.
Action: Glycogenolysis (breakdown of glycogen to glucose),
gluconeogenesis (synthesis of glucose from lactic acid and
noncarbohydrates), release of glucose to the blood. Hyperglycemic
hormone.
Hypersecretion: Overproduction develops when insulin levels too
low; weight loss, wasting, diabetes mellitus, anemia
Hyposecretion: Hypoglycemia
Pancreatic Hormones and Blood Sugar
Endocrine System II: Inferior Glands
 Adrenal Gland Hormones
• Cortex Hormones
 Aldosterone (mineralocorticoids)
 Cortisol (glucocorticoids)
 Androgens (gonadocorticoids)
• Medulla Hormones
 Epinephrine and Norepinephrine
(catecholamines)
 Pancreas
• Beta cell hormone: insulin
• Alpha cell hormone: glucagon
 Other Endocrine Tissues
• Pineal Gland
• Thymus
• Gonads (Ovaries and Testes)
Pineal Gland: Melatonin
 Found on the third
ventricle of the brain
 Secretes melatonin
• Helps establish the
body’s wake and
sleep cycles
• May have other asyetunsubstantiated
functions
Thymus: Thymosin
 Located posterior to the
sternum
 Largest in infants and
children
 Produces thymosin
• Matures some types
of white blood cells
• Important in
developing the
immune system
Hormones of the Ovaries: Estrogen
 Estrogens
• Produced by Graafian
follicles or the placenta
• Stimulates the
development of secondary
female characteristics
• Matures female
reproductive organs
• Helps prepare the uterus to
receive a fertilized egg
• Helps maintain pregnancy
• Prepares the breasts to
produce milk
Hormones of the Ovaries: Progesterone
 Progesterone
• Produced by the corpus luteum
• Acts with estrogen to bring about the
menstrual cycle
• Helps in the implantation of an embryo in
the uterus
Hormones of the Testes: Testosterone
 Interstitial cells of testes are hormoneproducing
 Produce several androgens
 Testosterone is the most important
androgen
• Responsible for adult male
secondary sex characteristics
• Promotes growth and maturation of
male reproductive system
• Required for sperm cell production
Other Hormone-Producing Tissues and Organs
 Gastrointesstinal tract (gastrin, secretin,
cholecystikinin
 Kidneys (erythropoietin, renin)
 Heart (atrial natriuretic peptide
 Skin (cholecalciferol)
 Skeleton: osteoblasts
 Adipose tissue: leptin for appetite control
 Many other areas have scattered endocrine cells
Endocrine Function of the Placenta
 Produces hormones that maintain
the pregnancy
 Some hormones play a part in the
delivery of the baby
 Produces human chorionic
gonadotropin (hCG) in addition to
estrogen, progesterone, and other
hormones
Developmental Aspects of the Endocrine System
 Most endocrine organs operate smoothly until old age
 Menopause is brought about by lack of efficiency of the ovaries
 Problems associated with reduced estrogen are common
 Growth hormone production declines with age
 Many endocrine glands decrease output with age
 Hormone-producing glands arise from all three germ layers
 Exposure to pesticides, industrial chemicals, arsenic, dioxin,
and soil and water pollutants disrupts hormone function
 Sex hormones, thyroid hormone, and glucocorticoids are
vulnerable to the effects of pollutants
 Interference with glucocorticoids may help explain high cancer
rates in certain areas
Endocrine System II: Inferior Glands
 Adrenal Gland Hormones
• Cortex Hormones
 Aldosterone (mineralocorticoids)
 Cortisol (glucocorticoids)
 Androgens (gonadocorticoids)
• Medulla Hormones
 Epinephrine and Norepinephrine
(catecholamines)
 Pancreas
• Beta cell hormone: insulin
• Alpha cell hormone: glucagon
 Other Endocrine Tissues
• Thymus
• Gonads (Ovaries and Testes)