1. Inquiry into Life Twelfth Edition
Lecture PowerPoint to accompany
Inquiry into Life Twelfth Edition
Sylvia S. Mader
Chapter 20
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. 20.1 Endocrine Glands and Hormones
The endocrine system consists of glands and tissues that secrete hormones
Hormones are chemicals that affect other glands or tissues, many times far away from the site of hormone production

3. 20.1 Endocrine Glands and Hormones
Hormones Influence:
Metabolism of cells
Growth and development of body parts
Homeostasis
Endocrine Glands
Are ductless
Secrete hormones into tissues, the hormones then diffuse into the bloodstream

4. 20.1 Endocrine Glands and Hormones
Hormones and Homeostasis
Homeostasis requires cooperation between the endocrine and nervous systems.
Endocrine System
Nervous System
Secretes hormones into the blood
Transmits nerve impulses
Slower response
Faster response
More prolonged response
Less prolonged response

5. The Endocrine System

6. 20.1 Endocrine Glands and Hormones
Control of the Production of Hormones
Negative Feedback
Action of other hormones

7. 20.1 Endocrine Glands and Hormones
Control of the Production of Hormones
Action of other hormones
Example: The anterior pituitary gland produces thyroid-stimulating hormone
The thyroid then produces hormones
Example: Antagonistic hormones
Insulin and glucagon

8. 20.1 Endocrine Glands and Hormones
The Action of Hormones
Two Classes of Hormones
Peptide Hormones
Steroid Hormones

9. Peptide Hormone Action

10. Steroid Hormone Action

11. 20.2 Hypothalamus and Pituitary Gland
Two Ways the Hypothalamus Regulates the Internal Environment
Through the Autonomic Nervous System
Heartbeat, blood pressure, appetite, body temperature, water balance
By Controlling the Pituitary Gland
Posterior Pituitary
Anterior Pituitary

12. 20.2 Hypothalamus and Pituitary Gland
Posterior Pituitary
Physically connected to the hypothalamus by a stalk
Hormones travel down axons and stored in axon terminals in posterior pituitary
Neurosecretory cells produce ADH and Oxytocin

13. 20.2 Hypothalamus and Pituitary Gland
Posterior Pituitary
ADH- Antidiuretic Hormone
Released from posterior pituitary in response to increased concentration of blood (not enough water)
ADH causes increased reabsorption of water in the kidneys
As water reabsorption occurs, the blood concentration becomes normal and ADH is shut off

14. 20.2 Hypothalamus and Pituitary Gland
Posterior Pituitary
Oxytocin
Causes uterine contractions and milk letdown in lactation
Neurological impulses from pressure and irritation of uterus causes oxytocin release
Oxytocin causes contractions which causes more pressure and irritation more oxytocin more contractions
An example of positive feedback
Neurological stimulus of suckling causes oxytocin release

15. 20.2 Hypothalamus and Pituitary Gland
Anterior Pituitary
Functionally connected to the hypothalamus by the bloodstream
Hypothalamus controls the anterior pituitary by producing:
Hypothalamic-releasing hormones
Hypothalamic-inhibiting hormones

16. 20.2 Hypothalamus and Pituitary Gland
Anterior Pituitary
Three anterior pituitary hormones have target effect on other glands
Thyroid stimulating hormone (TSH) stimulates thyroid gland to produce thyroid hormone
Adrenocorticotropic hormone (ACTH) stimulates the adrenal cortex to produce glucocorticoids
Gonadotrophic hormones (FSH & LH) stimulate the gonads to produce estrogen and testosterone

17. 20.2 Hypothalamus and Pituitary Gland
Anterior Pituitary
Three anterior pituitary hormones do not affect other glands
Prolactin (PRL) stimulates the mammary glands to synthesize milk
Melanocyte stimulating hormone (MSH) stimulates the pigment producing melanocytes of the skin
Growth hormone (GH) stimulates bone and muscle growth, increases protein synthesis and fat metabolism

18. Hypothalamus and the Pituitary

19. 20.3 Thyroid and Parathyroid Glands
Produces:
Triiodothyronine (T3) (four iodine atoms)
Thyroxin (T4) (three iodine atoms)
Thyroid requires iodine to produce these hormones
Iodine deficiency causes simple goiter
T3 and T4 increase metabolic rate
Stimulate most body cells to metabolize glucose

20. 20.3 Thyroid and Parathyroid Glands
Also Produces Calcitonin
Calcium-regulating hormone
Produced in response to increased blood calcium levels
Causes uptake of calcium by bone
Calcium is important in muscle contraction, nerve conduction, and blood clotting

21. Regulation of Blood Calcium Level

22. 20.3 Thyroid and Parathyroid Glands
Produce Parathyroid hormone (PTH)
Causes an increase in blood calcium and a decrease in blood phosphate
Increases osteoclast activity and the reabsorption of calcium by the kidneys
Also stimulates activation of vitamin D needed for calcium absorption in the digestive tract
When blood calcium levels increase, PTH is shut off

23. 20.4 Adrenal Glands The Adrenal Glands sit atop of the kidneys.
The two parts of the adrenal gland function independently
Adrenal Medulla (outer portion)
Under the control of the nervous system
Adrenal Cortex (inner portion)
Under the control of adrenocorticotropic hormone (ACTH)
An anterior pituitary hormone

24. 20.4 Adrenal Glands Adrenal Medulla
Receives nerve impulses from the hypothalamus
The adrenal medulla secretes two hormones:
Epinephrine (adrenaline)
Norepinephrine (NE)
Epinephrine and norepinephrine bring about a short-term response to stress (fight or flight response)

25. 20.4 Adrenal Glands Adrenal Cortex Under the control of ACTH
Two types of hormones
Glucocorticoids
Regulate carbohydrate, protein, and fat metabolism leading to an increase in blood glucose level
Mineralocorticoids
Regulate salt and water balance leading to an increases in blood volume and blood pressure

26. 20.4 Adrenal Glands Adrenal Cortex Glucocorticoids
Cortisol is the principal glucocorticoid hormone
Actions
Promotes breakdown of muscle proteins to amino acids
Liver uses amino acids to make glucose
Promotes metabolism of fatty acids, spares glucose
Overall: Promotes a rise in blood glucose
Beneficial under stress
Cortisol is also anti-inflammatory
Can also suppress the immune system

27. 20.4 Adrenal Glands Adrenal Cortex Mineralocorticoids
Aldosterone is the principal mineralocorticoid hormone that targets the kidney
Increases absorption of sodium, excretion of potassium
Increases blood volume and pressure
Controlled through the release of renin from the kidney

28. 20.4 Adrenal Glands Adrenal Cortex Mineralocorticoids continued
Renin is released when blood sodium levels and blood pressure is low
Activates angiotensinogen (a plasma protein) to angiotensin I
Angiotensin I is converted to angiotensin II by enzyme in lung capillaries
Angiotensin II stimulates the adrenal cortex to release aldosterone
Effect: Angiotensin II constricts arterioles
Aldosterone causes the kidneys to reabsorb sodium
Blood pressure rises

29. Regulation of Blood Pressure and Volume

30. 20.4 Adrenal Glands Adrenal Cortex Mineralocorticoids continued
Atrial Natriuretic Hormone (ANH)
Produced by the right atrium (heart) as a result of stretch
Represents an increase in blood volume
Inhibits the release of aldosterone
Results in natriuresis: excretion of sodium in the urine
Water follows passively so blood volume and therefore pressure decreases

31. Pancreas Pancreas is composed of two types of tissue
Exocrine portion releases digestive enzymes
Pancreatic islets are the endocrine portion of the gland. The islets produce and secrete:
Insulin
Glucagon

32. Pancreas Insulin Glucagon Released after eating
Stimulates uptake of glucose by cells
Especially muscle, liver, and adipose cells
Decreases blood glucose
Glucagon
Released before eating when glucose is low
Targets liver and adipose tissue
Increases blood glucose

33. Regulation of Blood Glucose Level

34. 20.6 Other Endocrine Glands
Testes
Under the influence of the gonadotropic hormones
Produce androgens (e.g., testosterone)
Responsible for male secondary sex characteristics
Growth of penis and testes, beard growth, enlargement of vocal folds and larynx
Stimulates oil production by oil glands
Involved in pattern baldness
Increased muscle development

35. The Side Effects of Anabolic Steroid Use

36. 20.6 Other Endocrine Glands
Ovaries
Under the influence of the gonadotropic hormones
Estrogen
Stimulates growth of uterus and vagina
Egg maturation
Female secondary sex characteristics
Breast development along with progesterone
Fat deposition
Progesterone
Regulation of uterine cycle along with estrogen

37. 20.6 Other Endocrine Glands
Thymus Gland
Secretes hormones involved with the maturation of T-lymphocytes hormones
Pineal Gland
Produces melatonin
Involved with sleep/wake cycles and circadian rhythms
Likely has a role in sexual development

38. 20.6 Other Endocrine Glands
Hormones from Other Tissues
Leptin
Produced by adipose tissue
Stimulates satiety center in hypothalamus
Prostaglandins
Produced from arachidonic acid
Act locally
Many different prostaglandins-many effects
Muscle contraction in uterus
Mediate effects of pyrogens
Reduce gastric secretions
Inhibit platelet aggregation

39. 20.6 Other Endocrine Glands
Hormones from Other Tissues
Growth factors
Stimulate mitosis in tissues
Some released in blood, others act locally
Granulocyte and Macrophage Colony-Stimulating Factor
Produced by many different tissues
Causes bone marrow stem cells to produce granulocytes and macrophages
Platelet-Derived Growth Factor
Wound healing
Epidermal Growth Factor and Nerve Growth Factor
Tumor Angiogenesis Factor
Formation of capillary networks to tumor cells

40. 20.7 Pheromones
Pheromones are chemical signals that act between individuals
Effects are better known in animals other than humans
Female moths release an attractant that acts on male moths
In humans:
Possible role in mate attraction
Axillary secretions can affect the menstrual cycle

41. 20.8 Disorders of the Endocrine System
Disorders of the Pituitary Gland
Diabetes insipidus (DI)
Posterior pituitary secretes too little ADH (antidiuretic hormone)
Large amounts of urine are produced resulting in dehydration
Pituitary Dwarfism
Too little growth hormone is secreted by the anterior pituitary
Characterized by small stature but normal proportions

42. 20.8 Disorders of the Endocrine System
Disorders of the Pituitary Gland
Gigantism
Excess growth hormone is produced during childhood
Gigantism also promotes the development of diabetes mellitus

43. 20.8 Disorders of the Endocrine System
Disorders of the Pituitary Gland
Acromegaly
Excess growth hormone in adulthood
Long bones cannot grow, so the effect is noticeable in the hands, feet, and facial bones

44. 20.8 Disorders of the Endocrine System
Disorders of the Pituitary Gland
Cushing Syndrome
Excess production of ACTH (usually due to a tumor)
Adrenal cortex then produces excess cortisol
Protein is metabolized, fat is deposited in the midsection

45. 20.8 Disorders of the Endocrine System
Disorders of the Thyroid
Hypothyroidism
Not enough thyroid hormone is produced
In children, cretinism results if left untreated
Individuals are short and stocky, mental retardation results if treatment does not begin within the first two months of life
Myxedema can occur in adults
Symptoms include lethargy, weight gain, hair loss, slow heart rate, and puffy skin
Treatment for both conditions in the administration of thyroid hormones

46. 20.8 Disorders of the Endocrine System
Disorders of the Thyroid
Goiter
Caused by an enlarged thyroid gland
The thyroid gland is being constantly stimulated by TSH
A lack of dietary iodine makes the thyroid unable to produce sufficient T3 and T4

47. 20.8 Disorders of the Endocrine System
Disorders of the Thyroid
Hyperthyroidism
Oversecretion of thyroid hormones
Symptoms include protruding eyes, nervousness, hyperactivity, and abnormal heart rhythms
Treatment may include destruction of the thyroid

48. 20.8 Disorders of the Endocrine System
Disorders of the Parathyroid
Insufficient parathyroid production results in a drop in blood calcium levels.
The body shakes from continuous muscle contraction (tetany)

49. 20.8 Disorders of the Endocrine System
Disorders of the Adrenal Glands
Addison Disease
Destruction of the adrenal cortex by the immune system
Symptoms include weakness, weight loss, abdominal pain, and a bronzing of the skin.
The decreased production of mineral corticoids can affect sodium and potassium levels, which can adversely affect the heart.

50. 20.8 Disorders of the Endocrine System
Diabetes Mellitus
Cells cannot take up glucose
As blood glucose rises, glucose and water are lost in the urine
Causes increased thirst, increased hunger
A glucose tolerance test is used many times for diagnosis

51. Glucose Tolerance Test

52. 20.8 Disorders of the Endocrine System
Diabetes Mellitus
Two types of Diabetes Mellitus
Type 1- Insulin Dependent
Lack of insulin- may be due to exposure to environmental agent such as a virus
May also be an autoimmune condition
As cells break down fats for energy, ketones build up in blood
Ketoacidosiscoma, death
Insulin overdose- causes hypoglycemia, unconsciousness
Immediate ingestion of glucose to counteract

53. 20.8 Disorders of the Endocrine System
Diabetes Mellitus
Two types of Diabetes Mellitus
Type 2 Diabetes Mellitus
Insulin-resistant
Obesity- adipose tissue produces a substance that impairs insulin receptor function
Insulin levels are often low, and cells may not have sufficient insulin receptors
Controlled by diet, exercise, medications
Long term complications of diabetes mellitus
Blindness, kidney disease, cardiovascular disorders