1. Endocrine system
Unit 9

2. Activator: 2.9.2016 What are the 8 glands of the endocrine system?
Think back a few chapters, what is translation and transcription?
Activator:

3. Role of endocrine system
Regulates reproduction, growth and development, defenses, balance of nutrients in the blood, metabolism, and energy use
0.5 pounds of endocrine tissue
Role of endocrine system

4. What are hormones? Chemical messengers
Hormone means “to arouse” by altering cellular activity
What are hormones?

5. Mechanisms of hormones action
Start by circulating in the blood
Hormones bind to certain cells or organs
Mechanisms of hormones action

6. Target Cell/Organ- The cell or organ a hormone attaches to
In order for the target to respond to the hormone, a protein receptor must be present on the plasma membrane or in the cell
Hormone attachment

7. Activation means the hormone causes a change in the target cell
2 types of hormone activation:
Steroids (cholesterol and sex hormones) are lipid soluble
Amino-acid based (proteins, peptides, and amines) are non-lipid soluble
Hormone activation

9. 1. Steroidal hormone activation
Lipid-soluble, so they can move through the plasma membrane
1. Steroidal hormone activation

10. Hormone diffuses through plasma membrane
Step 1

11. Step 2 Hormone binds to specific receptor protein
Becomes a hormone-receptor complex (HRC)
HRC enters the nucleus
Hormone (H) + Receptor Complex (RC) = HRC
Step 2

12. The HRC binds to DNA
Step 3

13. Step 4 Certain genes in the DNA are altered, new mRNA is transcribed
Think back to translation and transcription
Step 4

14. Step 5 mRNA is translated, new protein is created
This protein will cause the desired effect to the cell
Step 5

16. Amino-acid hormone activation:
Non lipid soluble, so the hormones must attach to the plasma membrane directly
Amino-acid hormone activation:

17. Hormone binds to membrane receptor attached to membrane
Step 1

18. Binding sets off a series of reactions that activates enzymes w/in the cell
Step 2

19. The enzyme then catalyzes (speeds up) a reaction that produces a messenger molecule
Step 3

20. Messenger molecule creates the change desired within the cell
Step 4

22. STEROIDAL Diffuse thru PM H + R = HRC, enters nucleus Bind to DNA
Alter genes of DNA & makes new mRNA
Make a new protein
STEROIDAL

23. NON- STERIODAL Attach to receptor in PM Enzymes are released
Speed up the production of a messenger molecule
Messenger molecule creates the desired effect on cell
NON- STERIODAL

24. How do glands know when to release hormones?

25. How do glands know when to release hormones?
Use negative feedback mechanisms to maintain hormone levels in the blood
How do glands know when to release hormones?

26. What are negative feedback mechanisms?
Too much of a hormone, the glands stop producing
Too little, and the glands produce more
What are negative feedback mechanisms?

27. What kinds of stimuli activate endocrine glands?
3 main categories of stimuli:
Hormonal
Humoral
Neural
What kinds of stimuli activate endocrine glands?

28. Endocrine organs are prodded by other hormones to create their own hormones
rhythmic/always working
Hormonal stimuli

29. Example of hormonal stimuli
Step 1: Hypothalamus secretes hormones that activate pituitary gland to release hormones.
Example of hormonal stimuli

30. Step 2: Pituitary gland releases hormones that activates adrenal glands AS WELL AS cut off the hormones of the hypothalamus

31. Step 3: New hormones are released by the adrenal glands into the body AS WELL AS cutting off the hormone production in the pituitary glands
This allows the hypothalamus to start producing hormones again

32. Initiated by low levels of ions or nutrients monitored by endocrine organs
Works in short bursts/ Used only when needed
Humoral stimuli

33. Neural stimuli Hormones respond to neural activity
Ex) responding to stress
Sympathetic nervous system produces norepinephrine which when stressed, which causes increased heart rate, blood pressure, etc.
Neural stimuli

34. Endocrine organs

35. Pituitary Gland “Master gland” Hangs by a stalk under the hypothalamus
2 parts:
Anterior
Posterior
Very small size of grape
Pituitary Gland

36. Anterior pituitary 6 total hormones produced here.
2 work on non-endocrine targets
4 work on other endocrine glands, these are called trophic hormones
Anterior pituitary

37. 2 Non-endocrine targets
Growth hormone (GH)- division of cells, growth of bones and muscle
Prolactin (PRL) - Milk production of the breasts
2 Non-endocrine targets

38. 4 endocrine gland targets
The 4 tropic hormones stimulate:
Follicle-stimulating (FSH)- Helps regulates menstrual cycle and egg production in women, sperm production in men
Luteinizing (LH)-
Thyroid-stimulating (TSH)- stimulates the thyroid to release its hormones
Adrenocorticotrophic (ACTH)- stimulates the adrenal glands to release their hormones
4 endocrine gland targets

39. Works directly with the hypothalamus to secrete the hormones produced by the hypothalamus
Posterior pituitary

40. 2 hormones from posterior pituitary
1. Oxytocin (OT) :common in women, stimulates contractions during labor, sex, and also causes milk ejection
2. Antidiuretic hormone (ADH) Kidneys reduce water excretion (inhibits urine production)
2 hormones from posterior pituitary

41. Large gland made up of two bulbs on each side of the trachea
Thyroid hormone
Calcitonin
Thyroid gland

42. Major metabolic hormone- Controls the rate at which glucose is converted into energy and heat
Also controls normal tissue growth and development
Thyroid Hormone

43. Decreases calcium levels in the blood by depositing calcium in the bones
Only secreted when calcium levels are high
Calcitonin

44. Tiny masses of tissue found on the posterior surface of the thyroid gland
Parathyroid glands (4)

45. Releases osteoclasts
Opposite role of calcitonin
Effect of PTH

46. Adrenal glands Curve over the top of the kidneys Adrenal cortex
Adrenal medulla
Adrenal glands

47. Hormones of the adrenal cortex
3 types:
Mineralocorticoids
Glucocorticoids
Sex hormones
Hormones of the adrenal cortex

48. Regulate mineral (or salt) & water balance in the blood
Mineralocorticoids

49. Glucocorticoids Increase blood glucose levels
Inhibit some pain-causing molecules (anti-inflammatory)
Glucocorticoids

50. Both produced in small amounts throughout life regardless of gender
Androgens (male sex hormone)
Estrogens (female sex hormone)
Testosterone is an androgen
Sex hormones

51. Hormones of the adrenal medulla
Epinephrine
Norepinephrine
Produced by stimulating SNS
Hormones of the adrenal medulla

52. Epinephrine and norepinephrine
AKA adrenaline and noradrenaline
Increase blood glucose and rate of metabolism
Spark the “fight or flight” response
Epinephrine and norepinephrine

53. The pancreas houses tiny little endocrine glands called the pancreatic islets
Insulin
Glucagon
Pancreas

54. Roles of insulin and glucagon
Both regulate the amount of sugar in the blood, but in opposite ways
Roles of insulin and glucagon

56. Small gland located in the brain
Pineal gland

57. Melatonin Effects how tired we are
Levels rise and fall throughout the day:
High levels = drowsy
Levels are lowest around noon
Melatonin

58. Thymus gland Located in the upper thorax, posterior to the sternum
Produces thymosin
Thymus gland

59. Thymosin Highly useful in immunity and defenses of the body
Stimulates the production of disease fighting T-cells
Only active until you hit puberty – slowly shrinks and is replaced by fat
Thymosin

60. Gonads Grouped by male and female organs Female gland: ovaries
Male gland: testes
Gonads

61. Ovaries Produce sex cells (ova, or eggs) Also produce 2 hormones:
Estrogen
Progesterone
Ovaries

62. Hormones of the ovaries
Estrogen stimulates development of the female reproductive organs
Progesterone acts with estrogen to bring about and regulate the menstrual cycle
Hormones of the ovaries

63. Testes Produce sex cells (sperm)
Also produce androgens (testosterone is the most common)
Testes

64. Hormones of the testes Androgens stimulate:
Development of the male reproductive organs
Secondary sex characteristics
Increases sex drive
Hormones of the testes

65. developmental gland: the placenta
The placenta is a temporary organ formed during pregnancy, found in the uterus
developmental gland: the placenta

66. What does the placenta do?
Helps to increase levels of estrogen and progesterone in the mother
This improves the lining of the uterus, further development of breasts, and lactation
What does the placenta do?