CHAPTER 13: ENDOCRINE SYSTEM OBJECTIVES

0.      Name the organs and functions of the endocrine system.

Organs:  Endocrine Glands

Functions

1 hypothalamus

1 maintain homeostasis

2 pituitary

2 fluid and electrolyte balance

3 pineal

3 fight-or-flight

4 thymus

 

5 thyroid

 

6 parathyroids

 

7 kidneys

 

8 adrenals

 

9 pancreas

 

10 ovaries

 

11 testes

 

 

1.         Explain why the endocrine system is so closely related to the nervous system.

 

The general function of the endocrine system is to integrate body systems (i.e. maintain homeostasis), in conjunction with the nervous system.  Recall that glands are effectors or responsive body parts that are stimulated by motor impulses from the autonomic nervous system.  Some of these glands, endocrine glands compose the endocrine system.

 

2.         Distinguish between an endocrine gland and an exocrine gland.

 

A.        ENDOCRINE GLAND = a gland that secretes hormones directly into the bloodstream a ductless gland.

 

B.        Exocrine gland = a gland that secretes substances into ducts which then leave the body (i.e. sweat/sebaceous glands) or into an internal space or lumen (i.e. digestive glands).  Exocrine glands are not part of the endocrine system!

 

3.         Define the term hormone and explain its general characteristics.

 

HORMONE = a very powerful substance secreted by an endocrine gland into the bloodstream, that affects the function of another cell or "target cell".

A.        General Characteristics:

 

1.         needed in very small amounts (potent)

2.         produce long-lasting effects in the cells they target

3.         regulate metabolic processes (maintain homeostasis)

4.         are regulated by negative-feedback mechanisms

             

4.         Distinguish between a steroidal and non-steroidal hormone, in terms of composition and action.

.          

            B.        Chemistry of Hormones

 

May be steroid (produced from cholesterol = fat-soluble) or non-steroid (water-soluble), which are usually amino acid based 

                                    1.         A steroid hormone passes easily through the target cell membrane

                                    2.         A non-steroid hormone requires a receptor on the target cell membrane to allow the hormone to enter the target cell.

 

5.         Locate the following endocrine glands (organs) on the diagram below:  hypothalamus, pituitary, pineal gland, thyroid, parathyroid, thymus, adrenals, pancreas, ovaries, and testes.

 


 

 


6.         Name the three endocrine glands (see above) that are actually divided into two endocrine glands with different functions.  Pituitary, adrenal, thyroid, pancreas

 

7.         For each of the glands listed in #5 & #6 above, name the hormone(s) they secrete, identify the target organ of each hormone, and the effect of each hormone. 

ENDOCRINE GLAND

HORMONE

TARGET(S)

RESPONSE/

EFFECT

HYPOTHALAMUS

RELEASING HORMONES

ANTERIOR PITUITARY GLAND

SECRETION OF HORMONES

HYPOTHALMIC AXONS EXTENDING INTO POSTERIOR PITUITARY

1. ADH

 

 

2. OXYTOCIN

1. KIDNEY TUBULES

 

2. UTERINE SMOOTH MUSCLE

1.  Reabsorption of water; increase in blood volume; increase in blood pressure

2.  contractions = labor and delivery

 

ANTERIOR PITUITARY GLAND

1. hGH

 

2. Prl

 

3. TSH

 

4. ACTH

 

5. FSH

 

 

6. LH

1.  BONE, MUSCLE, ADIPOSE

2.  MAMMARY GLANDS

3. THYROID GLAND

4. ADRENAL CORTEX

5a. OVARIAN FOLLICLE

5b.  MALE TESTES

6a. MATURE OVARIAN FOLLICLE

6b. TESTES

1.  growth

 

2.  mammary gland development

3.  secretion of hormones

 

4.  secretion of steroid hormones

5a.  ovarian follicle maturation

5b. sperm production

6a.  ovulation

 

 

6b.  testosterone production

 

THYROID GLAND

1. T3

2. T4

1 and 2.  ALL CELLS

1 and 2.  regulation of metabolic rate

 

ADRENAL CORTEX

1. CORTISOL

 

2. ALDOSTERONE

 

3. SUPPLEMENTAL SEX HORMONES

1.  ALL CELLS

 

2.  KIDNEY TUBULES

 

3. 2o SEX ORGANS

1.  regulation of metabolic rate

2. Reabsorption of sodium and water; increase in blood volume; increase in blood pressure

3.  female hair growth and maintenance of traits post-puberty

 

 

OVARIES

1. ESTROGEN

 

 

 

 

2. PROGESTERONE

 

1.  2o SEX ORGANS:  breasts, genitalia, adipose in hips, buttocks, thighs

 

2.  ENDOMENTRIUM OF UTERUS

1.  development at puberty and maintenance through life until menopause

 

 

2.  preparation of endometrium for implantation

TESTES

1. TESTOSTERONE

1.  2o SEX ORGANS:  genitalia, hair follicles in facial, axillary, inguinal regions, apocrine sweat glands, vocal cords, bone, muscle

1.  development at puberty and maintenance through life

 

 

 

 

PINEAL GLAND

1. MELATONIN

1.  LIMBIC SYSTEM

1. moods, emotions, circadian rhythm

THYROID GLAND

3. CALCITONIN

3a  OSTEOCLASTS

3b.  OSTEOBLASTS

3c  KIDNEY TUBULES

3a. inhibit activity

 

3b.  activated to use excess Ca to build bone

3c. secrete excess Ca in urine

Overall response = decrease in blood calcium

PARATHYROID GLANDS

1. PTH

1a.  OSTEOCLASTS

1b.  KIDNEY TUBULES

1c.  SMALL INTESTINE

1a.  activated to resorb bone

1b. increase reabsorption of calcium

1c. increase absorption of dietary calcium

Overall response =  increase in blood calcium

PANCREAS – ISLETS OF LANGERHANS

1.   BETA–CELLS

INSULIN

 

 

 

 

2.   ALPHA –CELLS GLUCAGON

1a.  MOST CELLS

 

1b.  LIVER

 

1c. SKELETAL MUSCLE

 

2a.  GLYOGEN IN LIVER

 

2b.  GLYCOGEN IN MUSCLE

Overall response =  decrease in blood glucose

 

 

 

 

 

Overall response = increase in blood glucose

 

8.         Name the "master" of the anterior pituitary gland.  HYPOTHALAMUS

 

9.         Define the term gonadotropin, name the two gonadotropins secreted by the anterior pituitary gland, and distinguish between them according to their actions.

 

            A gonadotropin, targets primary sex organs (ovary & testis).

            Follicle Stimulating Hormone (FSH)

a.         response depends upon sex:

o        In females, FSH stimulates maturation of an ovarian follicle and ovum

o        In males, FSH stimulates the maturation of sperm in the testes

b.         A gonadotropin, which targets primary sex organs (ovary & testis).

            Luteinizing Hormone (LH)

a.         response depends upon sex:

o        In females, LH causes ovulation

o        In males, LH causes secretion of testosterone.

b.         A gonadotropin, which targets ovaries & testes.

 

10.       Explain how the posterior pituitary gland does not produce hormones, but does secrete them.

POSTERIOR PITUITARY GLAND        

is continuous with axonal nerve fibers of the hypothalamus;

does not actually produce hormones (they are produced by the hypothalamus), but stores them until it is stimulated to release them

 

11.       Name the gland that requires iodine to produce most of its hormones.  THYROID

 

12.       Describe how calcium levels are maintained in the blood (recreate the negative feedback loop studied in BIO 137).

 

                        See blood calcium negative feedback loop in chapter 7.

 

13.       Name the two hormones that work together to regulate water and electrolyte levels in the blood and therefore regulate blood pressure.

           

ALDOSTERONE AND ADH

 

14.       Describe how glucose levels are maintained in the blood (create a negative feedback loop).

 

            See blood glucose negative feedback look created in class.

 

15.       Explain why the thymus gland decreases in size as we age.  MOST IMMUNITY IS PRODUCES IN INFANCY AND CHILDHOOD (i.e. no longer does much).

 

16.       Name the gland (hormone) whose production is stimulated by sunlight. PINEAL - MELATONIN

 

17.       Define the term gonad, list the primary gonads in both sexes, and name the hormones that target those gonads.

 

Gonads are defined as PRIMARY SEX ORGANS

 

The female gonads are called OVARIES, and gonadotropins that target them are FSH and LH.

The male gonads are called TESTES, , and gonadotropins that target them are FSH and LH.

 

18.       Explain what is meant by "secondary sexual characteristics", name the hormone that causes their development in both sexes, and list target organs.

Secondary (2o) sexual characteristics develop at puberty are then maintained throughout life.

In females, the hormone ESTROGEN causes development of Secondary (2o) sexual characteristics.  Female  Secondary (2o) sex organs include the BREASTS, EXTERNAL GENITALIA, and adipose tissue in the HIPS, BUTTOCKS, THIGHS.

In males, the hormone TESTOSTERONE causes development of Secondary (2o) sexual characteristics.  Male  Secondary (2o) sex organs include the EXTERNAL GENITALIA, hair follicles in the FACIAL, AXILLARY, INGUINAL regions, vocal cords, bones, and muscles.

 

19.  Name the hormones secreted by the ovary, distinguish which particular portion of the ovary secretes each, and name target organs and actions of those hormones.

OVARIES

1. ESTROGEN

 

 

 

 

2. PROGESTERONE

 

 

 

1.  2o SEX ORGANS:  breasts, genitalia, adipose in hips, buttocks, thighs

2.  ENDOMENTRIUM OF UTERUS

1.  development at puberty and maintenance through life until menopause

 

2.  preparation for implantation

 

20.       Outline the manner in which the hypothalamus functions to maintain homeostasis through the endocrine system.  Your flowchart should include the complete overview of glands, hormones secreted by those glands, target organ or site of those hormones, and effects (actions) of those hormones on the target organ or site.

 

            See flowchart created in class several times.

 

21.  Distinguish between dwarfism, giantism, and acromegaly.

 

            Growth Hormone Imbalances:

            1.         Pituitary Dwarfism = hyposecretion of GH during growth years.

a.         slow bone growth & closing of epiphyseal plates before normal height is reached

b.         Treatment = oral GH therapy.

                                    2.          Pituitary giantism = hypersecretion of GH during growth years.

a.         abnormal increase in the length of long bones.

                                    3.          Acromegaly = hypersecretion of GH during adulthood.

a.         Bones of hands, feet, cheeks, and jaw thicken

b.         Soft tissues also grow.

 

22.       Explain why so few cases of cretinism are seen today. NEONATAL BLOOD PANEL screens for T3 and T4 levels.

 

23.              Compare and contrast cretinism, myxedema, Grave's Disease, and goiter.

1.      Cretinism = hyposecretion of T3/T4 during fetal life and infancy.

a.         dwarfism & mental retardation

b.         prevention = newborn testing

c.         treatment = oral thyroid therapy.

                        2.         Myxedema = hyposecretion during adulthood.

a.         edema, slow heart rate, low body temp, dry hair & skin, muscular weakness, lethargy, weight gain

b.         Oral thyroid hormones reduce symptoms.

                        3.         Grave's Disease = an autoimmune disorder that causes growth of thyroid and   hypersecretion of thyroid hormones, with no negative feedback. a.  enlarged thyroid (2-3x larger)

b.         peculiar edema of the eyes (bulging)

c.         increased metabolic rate, heat intolerance, increased sweating, weight loss, insomnia, tremor, and nervousness.

d.         treatment = surgical removal, use of radioisotopes to destroy some of the thyroid. and anti-thyroid drugs to block

                        4.         Goiter = low thyroid hormones due to iodine deficiency.

                                    a.         No thyroid hormones inhibit pituitary release of TSH

                                    b.         Thyroid is overstimulated and enlarges, but still functions below normal levels.

                                               

24.              Distinguish between Addison's Disease and Cushing's Syndrome.

1.         Addison's Disease = hyposecretion of AC hormones due to autoimmunity or disease (TB).

Symptoms:      mental lethargy, anorexia, nausea, vomiting, weight loss, hypoglycemia, muscle weakness, ­K+, ¯Na+, ¯BP, dehydration, arrhythmias, cardiac arrest, ­skin pigmentation. 

2.         Cushing's Syndrome = hypersecretion of AC hormones due to pituitary tumor or steroid administration.

Symptoms:      redistribution of fat, thin limbs due to wasting of muscles (i.e. protein catabolism), "moon face", "buffalo hump", "beer belly", stretch marks, bruises, poor wound healing, hyperglycemia, osteoporosis, weakness, hypertension,  ­susceptibility to infection, ¯resistance to stress, mood swings.

Usual cause:    administration of steroids (i.e. prednisone) for transplant patients, asthma, and chronic inflammatory disorders.

 

25.              Compare and contrast the two types of the disease Diabetes Mellitus.

A.                Diabetes Mellitus.

1.                  Symptoms (3 poly's):  polyuria, polydypsia, polyphagia.  Two types:

a.         Type 1 /IDDM (10%):

o        absolute insulin deficiency, with insulin administration.

o        Patients < 20 years

o        autoimmune disorder where β-cells are destroyed

o        Hyperglycemia results.

o        Cells can't use glucose so fat is broken down, releasing ketone bodies, causing ketoacidosis, lowering blood pH, and causing death.

o        Complications include Atherosclerosis, CV disease, IHD, PVD, gangrene, blindness due to cataracts (lens) and retinal vascular disease renal failure.

o        Treatments:

1.         artificial pancreas that detects fall in glucose levels and automatically releases insulin

2.                  transplant of pancreas or Beta cells.

b.         Type 2/NIDDM (90%)

o        patients > 40 years,

o        overweight,

o        hypertension,

o        Problem is usually with receptors on target cells

o        Controlled by diet, exercise, and weight loss 

o        Drug Diabeta (glyburide) may help stimulate insulin secretion of β-cells (if low levels of insulin is the cause).

 

26.       Describe seasonal affective disorder (SAD) in terms of cause, symptoms, and treatment.  Melatonin defeciency.