Download File

1
Chapter 25
Hormones
HORMONES: AN OVERVIEW
2
• 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.
PowerPoint® Lectures for
Campbell Essential Biology, Fifth Edition, and
Campbell Essential Biology with Physiology,
Fourth Edition
– Eric J. Simon, Jean L. Dickey, and Jane B. Reece
Lectures by Edward J. Zalisko
© 2013 Pearson Education, Inc.
© 2013 Pearson Education, Inc.
HORMONES: AN OVERVIEW
• The endocrine system
– consists of all hormone-secreting cells and
– is the body’s main system for internal chemical
regulation.
3
HORMONES: AN OVERVIEW
• 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.
© 2013 Pearson Education, Inc.
© 2013 Pearson Education, Inc.
4
5
Figure 25.1
6
Endocrine
cell
Membraneenclosed
sacs
Blood
vessel
Hormone
molecules
Target cell
Receptor
protein
Adrenal glands
(type of endocrine
gland), which sit
atop the kidneys
Blast Animation: Signaling: Endocrine
Right click slide / select “Play”
© 2013 Pearson Education, Inc.
Figure 25.1a
7
Endocrine
cell
HORMONES: AN OVERVIEW
• There are two general mechanisms by which
hormones trigger changes in target cells:
Target cell
1. Water-soluble hormones trigger responses
without ever entering their target cells.
Receptor
protein
Membraneenclosed
sacs
Hormone
molecules
Blood
vessel
© 2013 Pearson Education, Inc.
8
9
Figure 25.2-1
10
Watersoluble
hormone
Receptor
protein
1
Target
cell
Plasma
membrane
Nucleus
Animation: Water-Soluble Hormone
Right click slide / select “Play”
© 2013 Pearson Education, Inc.
Figure 25.2-2
11
Watersoluble
hormone
Receptor
protein
1
Target
cell
Relay
molecules
2
Plasma
membrane
Signal
transduction
pathway
Figure 25.2-3
12
Watersoluble
hormone
Receptor
protein
1
Target
cell
2
Plasma
membrane
Signal
transduction
pathway
Relay
molecules
Cytoplasmic
response
or
3
Nucleus
Nucleus
Gene regulation
HORMONES: AN OVERVIEW
13
14
2. Lipid-soluble hormones trigger responses after
entering the target cell.
Blast Animation: Signaling via Steroid Hormones
Right click slide / select “Play”
© 2013 Pearson Education, Inc.
© 2013 Pearson Education, Inc.
15
Figure 25.3-1
16
Lipidsoluble
hormone
1
Target
cell
Nucleus
Animation: Lipid-Soluble Hormone
Right click slide / select “Play”
© 2013 Pearson Education, Inc.
Plasma
membrane
Figure 25.3-2
17
Figure 25.3-3
Lipidsoluble
hormone
18
Lipidsoluble
hormone
1
Target
cell
1
Target
cell
Plasma
membrane
2
Plasma
membrane
2
Receptor
protein
Receptor
protein
Nucleus
Nucleus
Figure 25.3-4
19
Lipidsoluble
hormone
1
Target
cell
3
Hormonereceptor
complex
THE HUMAN ENDOCRINE SYSTEM
• The human endocrine system consists of about a
dozen major glands that may have
Plasma
membrane
– only endocrine functions or
2
Receptor
protein
Nucleus
4
– endocrine and non-endocrine functions.
• The major endocrine glands in humans are spread
about the human body.
3
Hormonereceptor
complex
Gene regulation
© 2013 Pearson Education, Inc.
20
Figure 25.4
21
THE HUMAN ENDOCRINE SYSTEM
22
Hypothalamus
Pituitary gland
• Hormones have a wide range of
Thyroid gland
Parathyroid glands
(embedded within
thyroid)
– target cells and
– effects.
Adrenal glands
(atop kidneys)
Pancreas
Ovaries
(female)
Testes
(male)
© 2013 Pearson Education, Inc.
Table 25.1
23
Table 25.1a
24
Table 25.1b
25
The Pancreas
26
• 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.
© 2013 Pearson Education, Inc.
Figure 25.9
27
Body
cells take
up glucose
Insulin
Pancreas
releases insulin
1
Stimulus:
Rising blood
glucose
2
Blood
glucose
level falls
Liver
stores
glucose as
glycogen
3
• 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
Glucose level
Homeostasis:
Normal blood glucose level
Glucose level
The Pancreas
Stimulus:
Declining
blood glucose
– the target cells do not respond normally to insulin
(type 2, or non-insulin-dependent diabetes).
4
6
Blood
glucose level
rises
Pancreas
releases glucagon
5
Liver
breaks down
glycogen
Glucagon
© 2013 Pearson Education, Inc.
28
The Pancreas
29
Figure 25.10
30
• 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.
© 2013 Pearson Education, Inc.
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
31
The Adrenal Glands
• The adrenal medulla secretes epinephrine and
norepinephrine, hormones that
– enable a rapid, short-term response to stress and
– produce the “fight-or-flight” response.
2. the outer adrenal cortex.
© 2013 Pearson Education, Inc.
© 2013 Pearson Education, Inc.
32
33
The Adrenal Glands
• Stressful stimuli activate nerve cells in the
hypothalamus that send signals to stimulate the
adrenal medulla to secrete
• The adrenal cortex
– is also stimulated by the hypothalamus and
– secretes corticosteroid hormones (including
glucocorticoids) that provide a slower, longerlasting response to stress.
– epinephrine and
– norepinephrine.
© 2013 Pearson Education, Inc.
© 2013 Pearson Education, Inc.
Figure 25.11
35
STRESS
Adrenal
gland
Kidney
34
The Adrenal Glands
Figure 25.11c
36
Adrenal
medulla
Adrenal
cortex
Nerve 1
signals
Hypothalamus
3
Nerve
cell
Releasing hormone
Anterior pituitary
Adrenal
gland
Blood vessel
Spinal cord
(cross section)
Nerve cell
ACTH
Adrenal
medulla
4
Adrenal
medulla
Epinephrine and
norepinephrine
2
ACTH
Adrenal
cortex
5
Corticosteroids
Short-term stress response
Long-term stress response
• Glycogen broken down to glucose; increased blood
glucose
• Proteins and fats broken down and converted
to glucose, leading to increased blood glucose
• Increased blood pressure, breathing rate, heart rate,
and metabolic rate
• Immune system may be suppressed
• Change in blood flow patterns, leading to increased
alertness and decreased digestive activity
Kidney
Adrenal
cortex
Figure 25.11a
37
Figure 25.11b
38
Nerve 1
signals
Hypothalamus
3
Releasing hormone
Nerve
cell
Anterior pituitary
Blood vessel
Spinal cord
(cross section)
ACTH
Nerve cell
4
Adrenal
medulla
Epinephrine and
norepinephrine
Adrenal
cortex
ACTH
5
Corticosteroids
2
Long-term stress response
Short-term stress response
Figure 25.11d
39
The Gonads
Short-term stress response
• The gonads secrete sex hormones that
• Glycogen broken down to glucose; increased blood
glucose
– affect growth and development and
• Increased blood pressure, breathing rate, heart rate,
and metabolic rate
– regulate
• Change in blood flow patterns, leading to increased
alertness and decreased digestive activity
Long-term stress response
– reproductive cycles and
– sexual behavior.
• Proteins and fats broken down and converted
to glucose, leading to increased blood glucose
• Immune system may be suppressed
© 2013 Pearson Education, Inc.
40
The Gonads
41
• Estrogens
• Males and females have the same three types of
sex hormones:
– maintain the female reproductive system and
1. estrogens,
– promote the development of specific female
features, such as breasts and wider hips.
2. progestins, and
• Progestins, such as progesterone, are primarily
involved in preparing the uterus to support a
developing embryo.
3. androgens.
© 2013 Pearson Education, Inc.
The Gonads
• Androgens, mainly testosterone, stimulate the
development and maintenance of the male
reproductive system.
© 2013 Pearson Education, Inc.
The Gonads
© 2013 Pearson Education, Inc.
43
42