Endocrine System

Hormones and their actions

Endocrine vs. Exocrine Glands

• Endocrine glands secrete their products (hormones) into the blood stream where they are carried to the target cells.

Exocrine glands

• Exocrine glands secrete their products into a body cavity or to the outside.

Negative feedback• How the body maintains

homeostasis

Low Blood Sugar

Eat Food

High Blood Sugar

Pancreas secretesInsulin

Steroid Hormones (lipid soluble)

Steroid cell response

Non-steroid cell response

Non-steroid hormones• Peptides are short chains of

amino acids; most hormones are peptides. They are secreted by the pituitary, parathyroid, heart, stomach, liver, and kidneys.

Prostaglandins

• Hormone-like chemicals that affect local tissues only.

Hypothalamus

The hypothalamus produces two hormones:

* ADH* Oxytocin

* Controls pituitary gland

ADH: The single most important effect of antidiuretic hormone is to conserve body water by reducing the loss of water in urine.

Diabetes Insipidus: a hyposecretion

• With less ADH, the kidneys conserve less water

• Frequent urination (around 2.5 liters/day) and excessive thirst result

• May be caused by surgery, infection, head injury, tumor, or a genetic disorder.

Diabetes Insipidus: a hyposecretion of ADH

Oxytocin

• Stimulation of milk ejection (milk letdown

• Stimulation of uterine smooth muscle contraction at birth

• Establishment of maternal behavior

Pineal Gland

Melatonin

Pituitary Gland

Posterior Pituitary

• Stores ADH and Oxytocin

Anterior Pituitary Gland

• GH = Growth Hormone

– Stimulates cells to grow and divide– Enhances movement of amino acids

across the cell membrane– Tells cells to use more carbohydrates

Dwarfism: a hyposecretion of GH

Gigantism: a hypersecretion of GH

• Anna Swan• 7 feet 5 inches

Leonid Stadnyk: Tallest living man at 8 feet, 5.5 inches

Acromegaly: a hypersecretion of GH in Adults

• In acromegaly, an individual's hands and feet begin to grow, becoming thick and doughy. The jaw line, nose, and forehead also grow, and facial features are described as coarse. The tongue grows larger, and because the jaw is larger, the teeth become more widely spaced. Due to swelling within the structures of the throat and sinuses, the voice becomes deeper and sounds hollower, and patients may develop loud snoring.

TSH: Thyroid Stimulating Hormone

• Tells the thyroid gland to release its hormones (which control metabolism)

Cretinism: a hyposecretion of TSH in children

• Symptoms: – dwarfism– mental deficiency– puffy facial features– dry skin– large tongue– muscular incoordination

Myxedema: a hyposecretion of TSH in adults

• Myxedema:– most severe form of hyposecretion– swelling of feet, hands, face, and eye

tissues– disease leads to coma and death

Graves Disease: a hypersecretion of TSH

Graves Disease: Too much TSH

• Hyperthyroidism can be caused by the secretion of too much TSH.

• Graves Disease is an autoimmune disease. The thyroid gland doesn’t respond to negative feedback.

• Goiter results because an increase in TSH caused the thyroid to work harder

Graves disease• Tissues around eyes begin to swell,

causing the eyes to bulge out.• Eyes will be dry and irritated• Blindness may result• This disorder effects women more than

men by 8 to 1.• People tend to get this disorder in their

30’s to 40’s • Tends to run in families.

ACTH: Adrenocorticotropic Hormone

• Tells the adrenal cortex to secrete its hormones

Addison’s Disease: a hyposecretion of ACTH

Cushing’s Disease: A hypersecretion of ACTH

Cortisol

Known as the stress hormone

It increases blood pressure, blood sugar, suppresses the immune system

FSH: Follicle Stimulating Hormone

• High levels causes:– Premature menopause– Testicular failure

– Low levels cause:• Low sperm count• Lack of menstrual cycle

LH: Lutenizing Hormone

•

Prolactin

Thyroid Gland

Thyroxine and triiodothyronine

• Thyroxine = T4 because it has four iodine atoms.

• Triiodothyronine = T3 because it has three iodine atoms.

• These hormones help regulate the metabolism of carbs, lipids, and proteins.

Hyperthyroidism

Hypothyroidism

• Symptoms: Fatigue, weakness, weight gain, dry hair, depression, memory loss.

• 10% of women have some degree of this disorder.

• Easily fixed by taking more thyroxine through medication.

Goiters and iodine deficiency

X-ray of goiter. Goiter is pushing the trachea and esophagus to the side

Calcitonin

• Keeps calcium in your bones– Lowers blood calcium

Parathyroid Gland• PTH: Parathyroid Hormone

– Increases blood calcium levels

Thymus Gland• Thymopoiet

in and thymosin

Adrenal Glands

• Cortex and medulla

Cortex hormones:

• Glucocorticoids: Cortisone

• Mineralocorticoids: Aldosterone

• Gonadocorticoids: Androgens

Medulla hormones

• Epinephrine and Norepinephrine

Pancreas

• Alpha Cells: Glucagon

• Beta Cells: Insulin

Testes and Ovaries

• Ovaries: Estrogen and Progesterone

• Testes: Testosterone

Placenta

• HCG: human chorionic gonadotropin.