Human Biology
Sylvia S. Mader
Michael Windelspecht
Chapter 15
Endocrine
System
Lecture Outline
Part 3
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15.4 Adrenal Glands
6. Adrenal glands
• Glands that sit on top of the ________
• 2 parts of each gland
– Adrenal medulla: controlled by the nervous
system
– Adrenal cortex: portions are controlled by
ACTH from the anterior pituitary
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15.4 Adrenal Glands
The adrenal glands
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adrenal gland
kidney
adrenal cortex
connective
tissue capsule
zona
glomerulosa
adrenal medulla
adrenal cortex
(a)
zona
fasciculata
zona
reticularis
adrenal medulla
(b)
Figure 15.12 The adrenal glands.
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15.4 Adrenal Glands
Adrenal medulla
• Inner portion of the adrenal glands
• Hypothalamus initiates stimulation of hormone
secretion in the adrenal medulla
• Produces hormones that allow a short-term
response to stress (“fight or flight” response)
– Epinephrine (adrenaline)
– Norepinephrine
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15.4 Adrenal Glands
Adrenal cortex
• Outer portion of the adrenal glands
• Produces hormones that provide a long-term
response to ______
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15.4 Adrenal Glands
Adrenal cortex
• 2 major types of hormones
– Glucocorticoids
• regulate carbohydrate, protein, and fat
metabolism.
• suppress the body’s inflammatory response.
• e.g., cortisol and cortisone
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15.4 Adrenal Glands
Adrenal cortex
– Mineralocorticoids
• regulate salt and water balance.
• e.g., aldosterone (targets the kidney)
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15.4 Adrenal Glands
Summary of the adrenal glands
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
stress
hypothalamus
Neurosecretory
cells produce
hypothalamicreleasing
hormone.
path of nerve
impulses
Stress Response:
Long Term
Glucocorticoids
Protein and fat metabolism
instead of glucose
breakdown.
neuron
cell body
Anterior
pituitary
secretes
ACTH.
sympathetic fibers
spinal cord
(cross section)
ACTH
epinephrine
Reduction of inflammation;
immune cells are
suppressed.
Mineralocorticoids
Sodium ions and water
are reabsorbed by kidney.
norepinephrine
Blood volume and
pressure increase.
Stress Response:
Short Term
Heartbeat and blood
pressure increase.
Blood glucose level rises.
glucocorticoids
Muscles become
energized.
adrenal medulla
adrenal cortex
Figure 15.13 Response of the adrenal medulla and the adrenal cortex to stress.
mineralocorticoids
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15.4 Adrenal Glands
Adrenal glands can malfunction
•
_______________ – hyposecretion of glucocorticoids by
the adrenal cortex, characterized by bronzing of the skin
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a.
Figure 15.15 Addison disease.
b.
a: © Custom Medical Stock Photo; b: © NMSB/Custom Medical Stock Photo
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15.4 Adrenal Glands
Adrenal glands can malfunction
•
________________ – hypersecretion of glucocorticoids
by the adrenal cortex, characterized by weight gain in
the trunk of the body but not the arms and legs
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(both): Courtesy Shannon Halverson
Figure 15.16
Cushing syndrome.
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15.5 Pancreas
7. Pancreas
•
Fish-shaped organ behind the stomach
•
Composed of 2 tissues
– ______________: produces and secretes
digestive juices
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15.5 Pancreas
7. Pancreas
– ____________ (islets of Langerhans):
produces and secretes hormones
1. Insulin – secreted when blood glucose is high;
stimulates the uptake of glucose by cells
(muscle and liver)
2. Glucagon – secreted when blood glucose is
low; stimulates the breakdown of glycogen in
the liver
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15.5 Pancreas
Regulation of blood glucose
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
inslin
Liver stores
glucose from
blood as
glycogen.
80x
B cells in
pancreatic islet
Muscle cells
store glycogen
and build protein.
After eating,
pancreas
secretes insulin
into blood.
Adipose tissue
uses glucose
from blood to
form fat.
Glucose level
drops.
Homeostasis (normal blood glucose)
Glucose level
rises.
Between eating,
pancreas secretes
glucagon into
blood.
Liver breaks
down glycogen
to glucose.
Glucose enters
blood.
A cells in 80x
Pancreatic islet
Figure 15.18 Blood glucose
homeostasis.
Adipose tissue
breaks down fat.
glucagon
(both): © Victor P. Eroschenko
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