1. The Endocrine System

2. Learning Objectives
Distinguish between endocrine and exocrine glands and define the terms hormone and prostaglandins
Identify and locate the primary endocrine glands and list the major hormones produced by each gland
Describe the mechanisms of steroid and nonsteroid hormone action

3. Learning Objectives
Distinguish between endocrine and exocrine glands and define the terms hormone and prostaglandins
Identify and locate the primary endocrine glands and list the major hormones produced by each gland
Describe the mechanisms of steroid and nonsteroid hormone action

4. What is the system?
Made up of glands that produce and secrete hormones (chemical messengers)
Regulation of growth, metabolism, sexual development
Responses to stress and injury
Internal balance of body systems (homeostasis)

5. BIG IDEA
HORMONES are chemical MESSENGERS that act on target cells (or organs)
Endocrine – secretions inside the body
Exocrine – secretions outside the body (sweat)
What are endocrine glands? (ductless glands that secrete hormones into intracellular spaces.)
What is a target-organ cell? (a cell that has receptors for a specific hormone)
Performs the same general functions as the nervous system
Communication
Control
Provides slower, longer-lasting control by hormones secreted into and circulated by the blood

6. TWO MAJOR CLASSES Non steroidal
What are the two major classes of hormones? (nonsteroid and steroid hormones)
How do nonsteroid and steroid hormones differ? (Nonsteroid hormones are whole proteins, chains of amino acids, or simply versions of single amino acids. These hormones provide communication between endocrine glands and target organs. Steroids hormones are lipid soluble and pass directly through the plasma membrane of the target cell.)
What is a second messenger mechanism? (chemical that provides communication within a hormone’s target cell)

7. Mechanism of Steroid Hormone Action
What are steroid hormones? (hormones that can pass through the target cell’s membrane to the nucleus, where they bind with a receptor to form a hormone-receptor complex)
Give an example of a steroid hormone. (Estrogen)

8. Major Structures

9. REGULATION OF HORMONE
Hormone secretion is controlled by homeostatic feedback
Negative feedback: Mechanisms that reverse the direction of a change in a physiologic system
Positive feedback: (Uncommon) mechanisms that amplify physiologic changes
Give an example of positive feedback. (During labor, muscle contractions become stronger by means of a positive feedback mechanism that regulates the secretion of oxytocin.)
Give an example of negative feedback. (As blood sugar normalizes, insulin secretion decreases.)

11. Hormone Action Steroids - water soluble Non steroid hormones
Prostoglandins - act locally, on nearby organs
Prostaglandins (or tissue hormones) are powerful substances found in a wide variety of body tissues
A prostaglandin is often produced in a tissue and diffuses only a short distance to act on cells in that tissue
Influence respiration, blood pressure, gastrointestinal secretions and reproduction

12. Hormone Control The pituitary is often called the “master gland”
Its actions are controlled by the hypothalamus in the brain. )
Why is the anterior gland sometimes called the master gland? (It controls the thyroid gland, the adrenal cortex, the ovarian follicles, and the corpus luteum.)
What do the major hormones do? (ACTH stimulates the adrenal cortex, causing it to increase in size and secrete larger amounts of its hormones.)

13. Pituitary Gland Functions of major hormones TSH
22 = Thalamus
24 = Hypothalamus
Functions of major hormones
TSH
Stimulates growth of the thyroid gland
Stimulates it to secrete thyroid hormone
ACTH
Stimulates growth of the adrenal cortex
Stimulates thyroid to secrete glucocorticoids and mineralocorticoids

14. Control of Hormones Negative feedback system
When the hormone levels rise, the organ that secretes the hormone is switched off

15. Anterior pituitary gland (adenohypophysis)
Major hormones
Thyroid-stimulating hormone (TSH)
Adrenocorticotropic hormone (ACTH)
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
Growth hormone (GH)
Prolactin hormone (PH

16. Anterior Pituitary Hormones
Prolactin or PRL - PRL stimulates milk production from a woman's breasts after childbirth and can affect sex hormone levels from the ovaries in women and the testes in men.

17. Growth hormone or GH - GH stimulates growth in childhood and is important for maintaining a healthy body composition. In adults it is also important for maintaining muscle mass and bone mass. It can affect fat distribution in the body.

18. Problems with the pituitary gland can result in Dwarfism

19. Sites http://www.youtube.com/watch?v=4TKSjaWQWSs

22. Or a person can grow too much
Or a person can grow too much. These are pictures of the man known as “The Alton Giant”, Robert Wadlow.

23. Adrenocorticotropin or ACTH - ACTH stimulates production of cortisol by the adrenal glands. Cortisol, a so-called "stress hormone," is vital to survival. It helps maintain blood pressure and blood glucose levels.
Many diet aids claim that they block cortisol levels. Cortisol from stress may lead to fat deposits in the belly.

24. Thyroid-stimulating hormone or TSH - TSH stimulates the thyroid gland to make thyroid hormones, which, in turn, control (regulate) the body's metabolism, energy, growth and development, and nervous system activity.

25. Luteinizing hormone or LH - LH regulates testosterone in men and estrogen in women. (gonadotropin)
Follicle-stimulating hormone or FSH - FSH promotes sperm production in men and stimulates the ovaries to release eggs (ovulate) in women. LH and FSH work together to allow normal function of the ovaries or testes. (gonadotropin)

27. Posterior Pituitary Hormones
Oxytocin - Oxytocin causes milk letdown in nursing mothers and contractions during childbirth.

28. Posterior Pituitary Hormones
Antidiuretic hormone or ADH - ADH, also called vasopressin, is stored in the back part of the pituitary gland and regulates water balance. If this hormone is not secreted properly, this can lead to problems of sodium (salt) and water balance, and could also affect the kidneys so that they do not work as well.

29. Diuretics – increase urine production
Many common foods and drinks contain chemicals that are diuretics (alcohol)
Midol relieves symptoms of bloating because it contains a diuretic that will make you urinate more
Active Ingredients: (in each caplet): Acetaminophen (500 mg) (Pain Reliever), Caffeine (60mg) (Diuretic, Stimulant), Pyrilamine Maleate (15 mg) (Diuretic) Inactive Ingredients: Carnauba Wax, Croscarmellose Sodium, FD&C Blue 2, Hypromellose, Magnesium Stearate, Microcrystalline Cellulose, Pregelatinized Starch, Propylene Glycol, Shellac, Titanium Dioxide, Triacetin

30. Hypothalamus
Actual production of ADH and oxytocin occurs in the hypothalamus
After production in the hypothalamus, hormones pass along axons into the pituitary gland
The secretion and release of posterior pituitary hormones are controlled by nervous stimulation
In addition to oxytocin and ADH, what substances does the hypothalamus produce? (releasing and inhibiting hormones that travel to the anterior pituitary gland)
The hypothalamus regulates many body functions related to homeostasis. Give some examples. (body temperature, appetite, and thirst)

32. THYROID GLAND
The thyroid hormones control your metabolism, which is the body's ability to break down food and store it as energy and release of energy

33. THYROID HORMONES
Thyroxin (T4) & Tri-iodothyronine (T3) - both increase the rate at which cells release energy from carbohydrates
Calcitonin – regulates the blood concentration of calcium
• BMR – basal metabolic rate : how many calories the body must consume to maintain life

34. Problems with the Thyroid
Thyroid hormone is partly made of iodine. Iodine is essential for the formation of thyroxin. If a person doesn’t eat enough iodine, they can’t make thyroid hormone.
so it the size of the follicle grows • gland grows • GOITER.
Iodine is only found in seafood, so if salt wasn’t iodized, a lot of people wouldn’t get enough iodine, and there would be a lot of goiters.

35. Goiter

36. Hypothyroidism Before and After Treatment

37. Hypothyroidism

38. Cretinism (hypothyroidism in infants)

40. Hyperthyroidism (Grave’s Disease)

41. Parathyroid Glands
Located behind the thyroid, four tiny glands Parathyroid Hormone (PTH) - takes calcium from the bones to make it available in the blood

42. Signs of low calcium

43. Adrenal Glands Located at the top of the kidneys
Adrenal Cortex - outer area
Adrenal Medulla  - inner area
Adrenal Glands = Adrenaline

44. Adrenal Medulla
Epinephrine & Norepinephrine – increased heart rate, breathing rate, elevated blood pressure (fight or flight, response to stress)
People with severe life threatening allergies often carry injectors

45. Adrenal Cortex
Aldosterone – a mineralcorticoid, helps kidneys conserve sodium and excrete potassium, maintaining blood pressure
Cortisol – glucocortoid, keeps blood glucose levels stable
Adrenal Sex Hormones - androgens (male) and estrogens (female)
Where is the adrenal gland? (It curves over the top of each kidney.)
What are hormones secreted by the adrenal cortex called? (corticoids)
What are the adrenal cortex and the adrenal medulla? (The adrenal cortex is the outer part of an adrenal gland, the medulla is its inner part.)

46. Female Sex Glands The ovaries contain two structures that
secrete hormones
The ovarian follicles
Little pockets in which egg cells, or ova, develop
Secrete estrogen, the “feminizing hormone”
The corpus luteum
All egg cells in females are present at birth. They develop at puberty.

47. Female Sex Glands (cont’d)
Effects of estrogen
Development and maturation of breasts and external genitals
Development of adult female body contours
Initiation of menstrual cycle
Menarche: name give to first menstrual cycle.
Menopause: name given to the cessation of estrogen production

48. Male Sex Glands
The interstitial cells of the testes secrete the male hormone testosterone
Effects of testosterone
Maturation of external genitals
Beard growth
Voice changes at puberty
Development of musculature and body contours typical of the male
The cells of the testes produce what? (Sperm production is ongoing after puberty.)
The interstitial cells in the testes secrete what male sex hormone directly into the blood? (testosterone)

49. Adrenal Gland Disorders
Cushing’s syndrome
hypersecretion of cortisol
Round “moon” face and “buffalo hump”

50. Addison’s disease Hyposecretion of cortisol Low blood pressure results
Increased pigmentation

51. Pancreas
The pancreas is a large gland behind your stomach that helps the body to maintain healthy blood sugar (glucose) levels. Contains islands of cells called the Islets of Langerhans which secrete glucagon and insulin

52. Glucagon – stimulates the liver to break down glycogen, raises blood sugar concentration
Insulin – decreases blood sugar concentrations, affects the uptake of glucose by cells
*Both hormones work together to maintain a balance in the blood sugar

53. Diabetes
Diabetes Mellitus – results from an insulin deficiency, blood sugar rises (hypoglycemia) and excess is excreted in the urine.
Type I - insulin dependent diabetes mellitus or juvenile onset diabetes, often caused by inherited immune disorder that destroys pancreatic cells

54. Diabetic neuropathies are a family of nerve disorders caused by diabetes. People with diabetes can develop nerve damage throughout the body. Symptoms include pain, tingling, or numbness-loss of feeling-in the hands, arms, feet, and legs.  This can result in wounds that are slow to heal.

55. Type II – mature onset diabetes (usually after the age of 40), often individuals are overweight, can be controlled with diet and exercise
Blood sugar test, device pricks the finger and measures the amount of sugar in the blood

56. Injection of insulin will lower the blood sugar levels
Hypoglycemia can occur if levels become too low, can be cured with direct injection of glucose or with eating something high in sugar. This is why diabetics often have candy.

57. Diabetes Insipidus
Symptoms Excessive thirst  ---May be intense or uncontrollable May involve a craving for ice water Excessive urine volume
Diabetes insipidus (DI) is an uncommon condition that occurs when the kidneys are unable to conserve water as they perform their function of filtering blood. 
The amount of water conserved is controlled by antidiuretic hormone (ADH), also called vasopressin.
ADH is a hormone produced in a region of the brain called the hypothalamus.

58. Other Endocrine Glands
Pineal Gland – located between the cerebral hemispheres, secretes melatonin, important for maintaining Circadian rhythms (light and dark activity)
Thymus Gland – large in young children, gradually shrinks with age, secretes thymosins, important to immune function
The pineal gland is a small gland near the roof of the third ventricle of the brain
Glandular tissue predominates in children and young adults
Tissue becomes fibrous and calcified with age
Called third eye because its influence on secretory activity is related to the amount of light entering the eyes
Pineal Gland
Secretes melatonin, which
Inhibits ovarian activity
Regulates the body’s internal clock

59. Other Endocrine Structures
Other organs (stomach, intestines, and kidneys) produce endocrine hormones
Atrial natriuretic hormone (ANH)
Secreted by atrial wall of the heart
Stimulates sodium loss from the kidneys
Nearly every organ and system has an endocrine function.

60. Steroids
Anabolic steroids are artificially produced hormones that are the same as, or similar to, androgens, the male-type sex hormones in the body. There are more than 100 variations of anabolic steroids. The most powerful androgen is testosterone.