1. The Endocrine System: control with chemicals
Produces chemical signals (hormones) that integrate with nervous system to maintain homeostasis

2. Sensory flow of Hormones
Low on water, stomach full, or low blood sugar, for example…
stimulus
received
Retain water, release digestive enzymes, release glucose, etc.
stimulus converted to
molecular signal
Hormone travels through blood stream to target cells (kidney, stomach, liver, for example)
Cells
respond
Response may be determined by multiple hormones

3. Hormones control many major processes
Reproduction
Growth and development
Mobilization of body defenses
Maintenance of much of homeostasis
Regulation of metabolism

4. Hormones can be classified chemically
Most are 2 major types
Amino acid–based (amines, peptides, and proteins)
Steroids—made from cholesterol

5. Mechanisms of Hormone Action
Hormones affect only certain tissues = target cells or target organs
Target cells have specific protein receptors
Hormone-binding to receptors alters cellular activity

6. Participating…
The endocrine system makes chemical message molecules known as ____________ . Which of the following are at least partially under hormonal control?
hormones
A. Reproduction
B. Growth and development
C. Mobilization of body defenses
D. Maintenance of much of homeostasis
E. Regulation of metabolism

7. Effects Caused by Hormones
Change membrane permeability
Synthesize proteins (enzymes)
Activate or inactivate enzymes
Stimulate mitosis
Promote secretion
Calcium homeostasis of blood 9–11 mg/100 ml
Rising blood Ca2+
levels
Thyroid gland releases calcitonin
Osteoclasts degrade bone matrix and release Ca2+ into blood
PTH
Calcitonin
Calcitonin stimulates calcium salt deposit in bone
Parathyroid glands release parathyroid hormone (PTH)
Thyroid gland
Parathyroid glands
Falling blood Ca2+ levels
Imbalance
Why do they do all this again?

8. … to help control these…
Reproduction
Growth and development
Mobilization of body defenses
Maintenance of much of homeostasis
Regulation of metabolism

9. Two basic chemical mechanisms. (i. e
Two basic chemical mechanisms (i.e. how hormones interact with molecules)
Direct gene activation
steroid hormones mainly, also thyroid hormone
Second-messenger system

10. Direct Gene Activation (Steroid Hormone Action)
Cytoplasm
Nucleus
Steroid hormone
1. Steroid diffuses through plasma membrane of target cells
Plasma membrane of target cell

11. Direct Gene Activation (Steroid Hormone Action)
Cytoplasm
Nucleus
1. Lipid-like hormone diffuses through plasma membrane of target cells
2. Then it diffuses through nuclear membrane
Why? What’s in there?
Plasma membrane of target cell
DNA!!
Figure 9.1a, step 2

12. Direct Gene Activation (Steroid Hormone Action)
Cytoplasm
Nucleus
1. Lipid-like hormone diffuses through plasma membrane of target cells
2. Diffuses through nuclear membrane
3. Binds to protein receptor in nucleus
Receptor
protein
Hormone-receptor complex
Plasma membrane of target cell
Figure 9.1a, step 3

13. Direct Gene Activation (Steroid Hormone Action)
Cytoplasm
Nucleus
1. Lipid-like hormone diffuses through plasma membrane of target cells
2. Diffuses through nuclear membrane
3. Binds to specific protein within nucleus
4. Hormone-receptor complex turns gene ‘on’
Receptor
protein
Hormone-receptor complex
DNA
Plasma membrane of target cell
Figure 9.1a, step 4

14. Direct Gene Activation (Steroid Hormone Action)
1. Lipid-like hormone diffuses through plasma membrane of target cells
2. Diffuses through nuclear membrane
3. Binds to specific protein within nucleus
4. Binds to specific sites on the cell’s DNA
5. Genes activated = synthesis of new proteins, direct response
Steroid hormone
Cytoplasm
Nucleus
Receptor
protein
Hormone-receptor complex
DNA
mRNA
Plasma membrane of target cell
Figure 9.1a, step 5

15. Direct Gene Activation (Steroid Hormone Action)
Nucleus
Cytoplasm
Steroid hormone
Receptor
protein
Hormone-receptor complex
DNA
mRNA
New protein
Plasma membrane of target cell
Remember the term to describe changing mRNA to proteins?
Translation?!?
Figure 9.1a, step 6

16. Second-Messenger System (Nonsteroid Hormone Action)
1. Hormone binds to a membrane receptor
Nonsteroid hormone (first messenger)
Cytoplasm
Receptor protein
Plasma membrane of target cell

17. Second-Messenger System (Nonsteroid Hormone Action)
Nonsteroid hormone (first messenger)
Cytoplasm
1. Hormone binds to a membrane receptor
BUT, hormone does not enter the cell
Enzyme
Receptor protein
Plasma membrane of target cell
Figure 9.1b, step 2

18. Second-Messenger System (Nonsteroid Hormone Action)
Nonsteroid hormone (first messenger)
Cytoplasm
1. Hormone binds to a membrane receptor, but does not enter the cell
2. Sets off series of reactions/activates enzymes
Enzyme
ATP
Second messenger
cAMP
Receptor protein
Plasma membrane of target cell
Figure 9.1b, step 3

19. Second-Messenger System (Nonsteroid Hormone Action)
Cytoplasm
Nonsteroid hormone (first messenger)
Enzyme
Receptor protein
Second messenger
Effect on cellular function, such as glycogen breakdown
Plasma membrane of target cell
ATP
cAMP
1. Hormone binds to a membrane receptor, but doesn’t enter cell
2. Sets off series of reactions that activate enzymes
3. Second-messenger molecules made by activated enzymes, stimulate a response (i.e. change or make proteins) second hand
Figure 9.1b, step 4

20. …all to regulate… amazing!
Reproduction
Growth and development
Mobilization of body defenses
Maintenance of much of homeostasis
Regulation of metabolism

21. Participating…
Steroid hormones dissolve through the cell membrane because they are made of ________ molecules. They initiate the production of proteins via ___________ gene activation which essentially ‘turns on’ genes. __________ - messenger, nonsteroid hormones, activate enzymes that affect cell activity, but never enter the cell.
lipid (fat)
direct
Second

22. Control of Hormone Release
Hormone levels usu. maintained by negative feedback
Stimulus triggers release of hormone
Hormone release stops once appropriate level is reached
3 types of hormone stimuli: hormonal, humoral, and neural…
Calcium homeostasis of blood 9–11 mg/100 ml
Rising blood Ca2+
levels
Thyroid gland releases calcitonin
Osteoclasts degrade bone matrix and release Ca2+ into blood
PTH
Calcitonin
Calcitonin stimulates calcium salt deposit in bone
Parathyroid glands release parathyroid hormone (PTH)
Thyroid gland
Parathyroid glands
Falling blood Ca2+ levels
Imbalance

23. Hormonal Stimuli of Endocrine Glands
Most common stimuli
Endocrine glands activated by other hormones
Example:
Anterior pituitary hormones

24. Humoral Stimuli of Endocrine Glands
Changing levels of ions/nutrients stimulate hormone release
Humoral = body fluids like blood and bile
Examples:
Parathyroid hormone
Calcitonin
Insulin

25. Neural Stimuli of Endocrine Glands
Nerve impulses stimulate hormone release
Most = sympathetic nervous system
Examples include release of norepinephrine and epinephrine by adrenal medulla

26. Participating…
The most common stimuli for hormone release is the presence or absence of other ___________ . When ion or nutrient concentrations in the blood stimulate hormone release, the stimulus is referred to as ___________ . ________ stimuli of endocrine glands occur when nerve impulses stimulate hormone release directly.
hormones
humoral
Neural

27. Endocrine System Homework
Download assignment from website. Fill in table (hormones, targets and functions) and label glands on the diagram – as usual…
Due Wed 4/23.

28. Major Endocrine Glands and Hormones
Table 9.1 (2 of 4)

29. Pituitary Gland Size of a pea Hangs from hypothalamus
Two functional lobes
Anterior pituitary—glandular tissue
Posterior pituitary—nervous tissue
The “master endocrine gland”
Figure 9.3

30. Prepare for Quiz You may use your homework if you have it.
Put everything else away except writing implement.

31. Endocrine System Quiz ID the region/gland indicated by A.
ID the glands indicated by B.
Name 2 hormones produced by the posterior pituitary.
What is the target of PTH?
Steroid hormones act via __________ ______ activation. B

32. Pituitary–Hypothalamus Relationship
Pituitary hormone release is regulated by hypothalamus hormones (or nerve impulses from hypothalmus)

33. Anterior Pituitary Hormones
All proteins (or peptides)
Act via second-messenger systems
Regulated by hormonal stimuli from hypothalmus

34. Growth hormone disorders…
Pituitary dwarfism - hyposecretion of GH during childhood
Gigantism - hypersecretion of GH during childhood
Acromegaly - hypersecretion of GH during adulthood
age 16
age 33
age 9
age 52

35. Posterior Pituitary stores 2 hormones made by hypothalamus
Release stimulated by nerve impulses from hypothalamus

36. Participating…
The ________ ________ gland makes and releases 6 different hormones. Release of these hormones is controlled by other hormones of the _____________ region of the brain. The 2 hormones of the posterior pituitary are controlled by
Neural stimulation
hypothalamus
Other hormones
Nothing in particular
Estrogen
anterior pituitary
hypothalamus

37. Thyroid Gland Base of the throat 2 lobes connected by isthmus
2 hormones = Thyroid hormone (TH) and Calcitonin

38. Thyroid hormone requires iodine - made and stored in thyroid follicles
Calcitonin made in parafollicular cells
Lack of iodine = no TH production
No TH production = build-up of TSH from pituitary
Build-up of TSH = goiter

39. Other thyroid disorders…
Myxedema – adult hypothyroidism
physical and mental sluggishness
Graves’ disease – hyperthoyroidism
Increased metabolism, rapid heartbeat, weight loss, and exophthalmos
Cretinism – hyposecretion during childhood
Dwarfism, mental disability if untreated

40. Parathyroid Glands – tiny nodes behind thyroid
Secrete parathyroid hormone (PTH)
Osteoclasts remove calcium from bone
Kidneys and intestine absorb more calcium
Raise calcium levels in the blood

41. Hormonal Regulation of Calcium in Blood
Calcium homeostasis of blood 9–11 mg/100 ml
Falling blood
Ca2+ levels
Imbalance
Figure 9.10, step 6

42. Hormonal Regulation of Calcium in Blood
Calcium homeostasis of blood 9–11 mg/100 ml
Thyroid gland
Parathyroid glands
Falling blood
Ca2+ levels
Imbalance
Figure 9.10, step 7

43. Hormonal Regulation of Calcium in Blood
Calcium homeostasis of blood 9–11 mg/100 ml
PTH
Parathyroid glands release parathyroid hormone (PTH)
Thyroid gland
Parathyroid glands
Falling blood
Ca2+ levels
Imbalance
Figure 9.10, step 8

44. Hormonal Regulation of Calcium in Blood
Calcium homeostasis of blood 9–11 mg/100 ml
Osteoclasts
degrade bone matrix and release Ca2+ into blood
PTH
Parathyroid glands release parathyroid hormone (PTH)
Thyroid gland
Parathyroid glands
Falling blood
Ca2+ levels
Imbalance
Figure 9.10, step 9

45. Hormonal Regulation of Calcium in Blood
Calcium homeostasis of blood 9–11 mg/100 ml
Osteoclasts
degrade bone matrix and release Ca2+ into blood
PTH
Parathyroid glands release parathyroid hormone (PTH)
Thyroid gland
Parathyroid glands
Figure 9.10, step 10

46. Hormonal Regulation of Calcium in Blood
Calcium homeostasis of blood 9–11 mg/100 ml
Rising blood Ca2+
levels
Thyroid gland releases calcitonin
Osteoclasts degrade bone matrix and release Ca2+ into blood
PTH
Calcitonin
Calcitonin stimulates calcium salt deposit in bone
Parathyroid glands release parathyroid hormone (PTH)
Thyroid gland
Parathyroid glands
Falling blood Ca2+ levels
Imbalance
Figure 9.10, step 11

47. Participating…
Lack of iodine prevents the __________ gland from making __________ hormone. As a result, TSH from the _____________ continues to accumulate in the thyroid causing a condition known as __________ .
thyroid
thyroid
pituitary gland
goiter

48. Adrenal Glands Sit on top of the kidneys: 2 regions
Adrenal cortex—outer glandular region has three layers
Mineralocorticoids area
Glucocorticoids area
Sex hormones area – released in low levels throughout life
Adrenal medulla—inner neural tissue region

49. Mineralocorticoids (mainly aldosterone) targets kidneys
Regulate water and electrolyte (mineral) concentrations
Long term stress or low blood volume

50. Glucocorticoids (cortisone, cortisol)
Boosts blood sugar, resists long-term stress
Short term
More prolonged
Stress
Hypothalamus
Nerve impulses
Adrenal cortex
Releasing hormone
Corticotropic cells of anterior pituitary
ACTH
Mineralocorticoids
Glucocorticoids
Retention of sodium and water by kidneys
Increased blood volume and blood pressure
1. Proteins and fats converted to glucose or broken down for energy
2. Increased blood sugar
3. Suppression of immune system
Long-term stress response
Short-term stress response
Spinal cord
Adrenal medulla
Preganglionic sympathetic fibers
Catecholamines (epinephrine and norepinephrine)
1. Increased heart rate
2. Increased blood pressure
3. Liver converts glycogen to glucose and releases glucose to blood
4. Dilation of bronchioles
5. Changes in blood flow patterns, leading to increased alertness and decreased digestive and kidney activity
6. Increased metabolic rate

51. Hormones of Adrenal Medulla = epiniphrine, norepinephrine
Hormones of Adrenal Medulla = epiniphrine, norepinephrine - sympathetic control, i.e. ‘fight or flight’
Short term
Stress
Hypothalamus
Figure 9.13, step 1

52. Hormones of Adrenal Medulla = epiniphrine, norepinephrine
Hormones of Adrenal Medulla = epiniphrine, norepinephrine - sympathetic control, i.e. ‘fight or flight’
Short term
Stress
Hypothalamus
Nerve impulses
Spinal cord
Figure 9.13, step 2

53. Hormones of Adrenal Medulla = epiniphrine, norepinephrine
Hormones of Adrenal Medulla = epiniphrine, norepinephrine - sympathetic control, i.e. ‘fight or flight’
Short term
Stress
Hypothalamus
Nerve impulses
Spinal cord
Adrenal medulla
Preganglionic sympathetic fibers
Figure 9.13, step 3

54. Hormones of Adrenal Medulla = epiniphrine, norepinephrine
Hormones of Adrenal Medulla = epiniphrine, norepinephrine - sympathetic control, i.e. ‘fight or flight’
Short term
Stress
Hypothalamus
Nerve impulses
Short-term stress response
Spinal cord
Adrenal medulla
Preganglionic sympathetic fibers
Catecholamines (epinephrine and norepinephrine)
Under neural control
Figure 9.13, step 4

55. Hormones of Adrenal Medulla = epiniphrine, norepinephrine
Hormones of Adrenal Medulla = epiniphrine, norepinephrine - sympathetic control, i.e. ‘fight or flight’
Short term
Stress
Hypothalamus
Nerve impulses
Short-term stress response
Spinal cord
Adrenal medulla
Preganglionic sympathetic fibers
Catecholamines (epinephrine and norepinephrine)
1. Increased heart rate
2. Increased blood pressure
3. Liver converts glycogen to glucose and releases glucose to blood
4. Dilation of bronchioles
5. Changes in blood flow patterns, leading to increased alertness and decreased digestive and kidney activity
6. Increased metabolic rate
Short term response to stress: increased heart rate, blood pressure, alertness, metabolic rate
Figure 9.13, step 5

56. Adrenal Gland disorders
Addison’s disease – hyposectretion of cortex hormones
Bronze skin tone, weak muscles, burnout from stress, susceptibility to infection
Hyperaldosteronism - excess water and sodium are retained = high blood pressure and edema
Masculinization – hypersecretion of sex hormones
Beard and male distribution of hair growth

57. Pancreatic Islets – endocrine part of pancreas
2 hormones – insulin and glucagon maintain blood sugar

58. Homeostasis: Normal blood glucose levels (90 mg/100ml)
Insulin Action
Diabetes mellitus: functional insulin not produced or receptors don’t function (capillary damage, impaired immune system among many others)
Insulin-secreting cells of the pancreas activated; release insulin into the blood
Uptake of glucose from blood is en- hanced in most body cells
Blood glucose levels decline to set point; stimulus for insulin release diminishes
Elevated blood sugar levels
Liver takes up glucose and stores it as glycogen
Stimulus: rising blood glucose levels (e.g., after eating four jelly doughnuts)
Homeostasis: Normal blood glucose levels (90 mg/100ml)
Figure 9.15, step 7

59. Homeostasis: Normal blood glucose levels (90 mg/100ml)
Glucagon Action
Stimulus: declining blood glucose levels (e.g., after skipping a meal)
Homeostasis: Normal blood glucose levels (90 mg/100ml)
Low blood sugar levels
Rising blood glucose levels return blood sugar to homeostatic set point; stimulus for glucagon release diminishes
Glucagon-releasing cells of pancreas activated; release glucagon into blood; target is the liver
Liver breaks down glycogen stores and releases glucose to the blood
Figure 9.15, step 12

60. Pineal Gland – tiny gland of the brain
Secretes melatonin
Coordinates wake and sleep cycles
Believed to coordinate fertility hormones
Depression in the dark: linked to melatonin over-production

61. Thymus Gland Posterior to the sternum
Largest children, declines with age
Produces thymosin
Helps develop immune system

62. Gonads Ovaries – produce eggs 2 groups of steroid hormone Estrogens
Progesterone
Testes – produce sperm
Produce androgens (testosterone)

63. Participation
Match the following glands with their hormones or functions.
Estrogen, progesterone: female reproductive cycles
melatonin: sleep cycles
Testosterone: male reproductive features
Norepinephrine, epinephrine: fight or flight
insulin, glucagon: blood sugar control
Pineal Gland
Pancreatic Islets
Testes
Ovaries
Adrenal Medulla

64. Other Hormone-Producing Tissues and Organs
Parts of small intestine, stomach, kidneys, heart
Nearly all cells release hormones if damaged
Placenta – hormones produced (like hCG) to maintain pregnancy and manage delivery
Reduced O2 levels in blood
Erythropoietin stimulates
Kidney releases erythropoietin
Enhanced erythropoiesis
Red bone marrow
More RBCs
Normal blood oxygen levels

65. Other Hormone-Producing Tissues and Organs
Table 9.2 (1 of 2)

66. Other Hormone-Producing Tissues and Organs
Table 9.2 (2 of 2)