25 Lecture Presentation PC.ppt -...

© 2013 Pearson Education, Inc.Lectures by Edward J. Zalisko

PowerPoint® Lectures forCampbell Essential Biology, Fifth Edition, and

Campbell Essential Biology with Physiology,

Fourth Edition– Eric J. Simon, Jean L. Dickey, and Jane B. Reece

Chapter 25Chapter 25Hormones

1 HORMONES: AN OVERVIEW

• Hormones are produced by most plants and

animals.

• Animal hormones

– are made and secreted mainly by endocrine glands,

– are usually carried by the circulatory system, and

– communicate regulatory messages to specific sites in the body.

© 2013 Pearson Education, Inc.

2

• The endocrine system

– consists of all hormone-secreting cells and

– is the body’s main system for internal chemical regulation.

HORMONES: AN OVERVIEW


3

• Endocrine cells secrete into the bloodstream

hormones that

– can affect many cells in many different body organs but

– only affect target cells, cells that have receptors for that specific hormone.



4


Blast Animation: Signaling: EndocrineRight click slide / select “Play”

5 Figure 25.1

Endocrine

cell

Blood

vessel

Membrane-enclosedsacs

Hormone

molecules

Receptor

protein

Target cell

Adrenal glands(type of endocrine

gland), which sitatop the kidneys

6

Figure 25.1a

Endocrinecell

Bloodvessel

Membrane-enclosedsacs

Hormonemolecules

Receptorprotein

Target cell

7

• There are two general mechanisms by which

hormones trigger changes in target cells:

1. Water-soluble hormones trigger responses without ever entering their target cells.



8


Animation: Water-Soluble HormoneRight click slide / select “Play”

9 Figure 25.2-1

Water-solublehormone Receptor

protein

Target cell Plasma

membrane

Nucleus

1

10

Figure 25.2-2


protein

Target cell Plasma

membrane

Relaymolecules

Signaltransduction

pathway

Nucleus

1

2

11 Figure 25.2-3


protein

Target cell Plasma

membrane

Relaymolecules

Signaltransduction

pathway

Cytoplasmicresponse

or

Gene regulationNucleus

1

2

3

12

2. Lipid-soluble hormones trigger responses after entering the target cell.



13


Blast Animation: Signaling via Steroid HormonesRight click slide / select “Play”

14


Animation: Lipid-Soluble HormoneRight click slide / select “Play”

15 Figure 25.3-1

Lipid-solublehormone

Target cell

Plasmamembrane

1

Nucleus

16

Figure 25.3-2


Receptorprotein

Target cell

Plasmamembrane

2

1

Nucleus

17 Figure 25.3-3


Receptorprotein

Target cell

Plasmamembrane

Hormone-receptorcomplex

Nucleus

2

1

3

18

Figure 25.3-4


Receptorprotein

Target cell

Plasmamembrane

Hormone-receptorcomplex

Gene regulation

Nucleus

2

1

3

4

19 THE HUMAN ENDOCRINE SYSTEM

• The human endocrine system consists of about a

dozen major glands that may have

– only endocrine functions or

– endocrine and non-endocrine functions.

• The major endocrine glands in humans are spread

about the human body.


20

Figure 25.4

Thyroid gland

Pituitary gland

Hypothalamus

Parathyroid glands(embedded within thyroid)

Adrenal glands(atop kidneys)

Testes(male)

Pancreas

Ovaries(female)

21

• Hormones have a wide range of

– target cells and

– effects.

THE HUMAN ENDOCRINE SYSTEM


22

Table 25.1 23 Table 25.1a 24

Table 25.1b 25 The Pancreas

• The pancreas produces two antagonistic

hormones that play important roles in managing

the body’s energy supplies:

1. insulin, which reduces blood sugar levels and

2. glucagon, which increases blood sugar levels.


26

Figure 25.9

Pancreas releases insulin

Stimulus:Rising blood glucose Glucose level

Homeostasis: Normal blood glucose level

Insulin

3

2

1

6

5

4

Bodycells takeup glucose

Liver storesglucose asglycogen

Blood glucoselevel falls

Stimulus:Decliningblood glucose

Glucose level

Glucagon

Pancreasreleases glucagon

Liverbreaks downglycogen

Bloodglucose levelrises

27

• Diabetes mellitus is a serious hormonal disease

in which body cells are unable to absorb glucose

from the blood because either

– there is not enough insulin produced (type 1, or insulin-dependent diabetes) or

– the target cells do not respond normally to insulin (type 2, or non-insulin-dependent diabetes).

The Pancreas


28

• Diabetes affects about 8% of all Americans.

• More than 90% of those affected have type 2

diabetes, which is associated with being

– overweight and

– underactive.

• People with diabetes use glucose meters to

measure the amount of glucose in the blood.

The Pancreas


29 Figure 25.10 30

The Adrenal Glands

• The adrenal glands are paired structures resting

atop each kidney.

• Each adrenal gland consists of two glands:

1. the central adrenal medulla and

2. the outer adrenal cortex.


31

• The adrenal medulla secretes epinephrine and

norepinephrine, hormones that

– enable a rapid, short-term response to stress and

– produce the “fight-or-flight” response.

The Adrenal Glands


32

• Stressful stimuli activate nerve cells in the

hypothalamus that send signals to stimulate the

adrenal medulla to secrete

– epinephrine and

– norepinephrine.

The Adrenal Glands


33

• The adrenal cortex

– is also stimulated by the hypothalamus and

– secretes corticosteroid hormones (including glucocorticoids) that provide a slower, longer-lasting response to stress.

The Adrenal Glands


34

Figure 25.11

Adrenalgland

Adrenalmedulla

AdrenalcortexKidney

Adrenal cortex

Nervesignals

Nervecell

Nerve cell

Spinal cord(cross section)

Adrenal medulla

Epinephrine andnorepinephrine

Corticosteroids

ACTH

Anterior pituitary

Releasing hormone

Blood vessel

Hypothalamus

STRESS

Long-term stress responseShort-term stress response

ACTH

• Proteins and fats broken down and convertedto glucose, leading to increased blood glucose

• Immune system may be suppressed

• Glycogen broken down to glucose; increased bloodglucose

• Increased blood pressure, breathing rate, heart rate,and metabolic rate

• Change in blood flow patterns, leading to increasedalertness and decreased digestive activity

3

1

2

4

5

35 Figure 25.11c

Adrenalmedulla

Adrenalcortex

Adrenalgland

Kidney

36

Figure 25.11a

1

2

Nervesignals

Nervecell

Nerve cell

Spinal cord(cross section)

Adrenal medulla

Epinephrine andnorepinephrine

Short-term stress response

37 Figure 25.11b

3

4

5

Adrenal cortex

Corticosteroids

ACTH

Anterior pituitary

Releasing hormone

Blood vessel

Hypothalamus

Long-term stress response

ACTH

38

Figure 25.11d

Long-term stress response

Short-term stress response

• Proteins and fats broken down and convertedto glucose, leading to increased blood glucose

• Immune system may be suppressed

• Glycogen broken down to glucose; increased bloodglucose

• Increased blood pressure, breathing rate, heart rate,and metabolic rate

• Change in blood flow patterns, leading to increasedalertness and decreased digestive activity

39 The Gonads

• The gonads secrete sex hormones that

– affect growth and development and

– regulate

– reproductive cycles and

– sexual behavior.


40

• Males and females have the same three types of

sex hormones:

1. estrogens,

2. progestins, and

3. androgens.

The Gonads


41

• Estrogens

– maintain the female reproductive system and

– promote the development of specific female features, such as breasts and wider hips.

• Progestins, such as progesterone, are primarily

involved in preparing the uterus to support a

developing embryo.

The Gonads


42

• Androgens, mainly testosterone, stimulate the

development and maintenance of the male

reproductive system.

The Gonads


43

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