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Chapter 13 Endocrine System

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Presentation on theme: "Chapter 13 Endocrine System"— Presentation transcript:

1 Chapter 13 Endocrine System
Endocrine glands are ductless Exocrine glands have ducts

2 Endocrine Glands Paracrine secretions Endocrine glands act locally
release hormones hormones travel through blood to target cells Paracrine secretions act locally affect only neighboring cells Autocrine secretions affect only the secreting cell

3 Comparison of Nervous System and Endocrine System
Neurons release neurotransmitters into a synapse, affecting postsynaptic cells Glands release hormones into the bloodstream Only target cells of hormone responds

4 Comparison of Nervous System and Endocrine System

5 Major Endocrine Glands

6 Chemistry of Hormones Nonsteroid Hormones
amines proteins peptides glycoproteins most hormones Steroid or Steroid-Like Hormones sex hormones adrenal cortex hormones

7 Types of Hormones

8 Structural Formulas of Hormones

9 Actions of Steroid Hormones
hormone crosses membranes hormone combines with receptor in nucleus synthesis of mRNA activated mRNA enters cytoplasm to direct synthesis of protein

10 Actions of Steroid Hormones

11 Actions of Nonsteroid Hormones
hormone binds to receptor on cell membrane adenylate cyclase activated ATP converted to cAMP cAMP promotes a series of reactions leading to cellular changes

12 Actions of Nonsteroid Hormones

13 Prostaglandins paracrine substances act locally
very potent in small amounts regulate cellular responses to hormones can activate or inhibit adenylate cyclase controls cAMP production alters cell’s response to hormones wide variety of functions

14 Control of Hormonal Secretions
primarily controlled by negative feedback mechanism

15 Negative Feedback

16 Major Endocrine Glands

17 Pituitary Gland Two distinct portions
anterior pituitary (adenohypophysis) posterior pituitary (neurohypophysis)

18 Pituitary Gland Control
Hypothalamic releasing hormones stimulate cells of anterior pituitary to release hormones Nerve impulses from hypothalamus stimulate nerve endings in the posterior pituitary gland to release hormones

19 Hypothalamic Hormones

20 Hormones of the Pituitary Gland

21 Thyroid Gland

22 Thyroid Gland Hormones

23 Disorders of the Thyroid Gland

24 Disorders of the Thyroid Gland
Graves Disease Hyperthyroidism Cretinism Infantile hypothyroidism

25 Parathyroid Glands

26 Parathyroid Hormone

27 Parathyroid Hormone Mechanism by which PTH promotes calcium absorption in the intestine

28 Disorders of the Parathyroid Glands

29 Adrenal Glands

30 Hormones of the Adrenal Medulla

31 Hormones of the Adrenal Cortex

32 Hormones of the Adrenal Cortex

33 Hormones of the Adrenal Cortex

34 Pancreas

35 Hormones of the Pancreatic Islets

36 Insulin and Glucagon Insulin and glucagon function together to stabilize blood glucose concentrations

37 Other Endocrine Glands
Pineal Gland secretes melatonin regulates circadian rhythms Thymus Gland secretes thymosins promotes development of certain lymphocytes important in role of immunity

38 Other Endocrine Glands
Reproductive ovaries produce estrogens and progesterone testes produce testosterone placenta produces estrogens, progesterone, and gonadotropins

39 Stress Types of Stress physical stress psychological stress

40 Responses to Stress

41 Life-Span Changes endocrine glands decrease in size
muscular strength decreases as GH levels decrease ADH levels increase due to slower break down in liver and kidneys calcitonin levels decrease; increase risk of osteoporosis PTH level changes contribute to risk of osteoporosis insulin resistance may develop changes in melatonin secretion affect the body clock thymosin production declines increasing risk of infections

42 Clinical Application Growth Hormone Ups and Downs
Gigantism - hypersecretion of GH in children Acromegaly – hypersecretion of GH in adults Dwarfism – hyposecretion of GH in children Figure shows oversecretion of GH in adulthood as changes occur in the same person at ages (a) nine, (b) sixteen, (c) thirty-three, and (4) fifty-two

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