Download Chapter 13

PowerPoint Lecture Outlines
to accompany
Hole’s Human
Anatomy and Physiology
Eleventh Edition
Shier w Butler w Lewis
Chapter
13
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
1
Chapter 13
Endocrine System
• Endocrine glands
are ductless
• Exocrine glands
have ducts
2
Endocrine Glands
Paracrine secretions
Endocrine glands
• act locally
• release hormones
• affect only neighboring cells
• hormones travel
through blood to target
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
Steroid or Steroid-Like
Hormones
• sex hormones
• adrenal cortex
hormones
Nonsteroid Hormones
• amines
• proteins
• peptides
• glycoproteins
• most 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
43