the endocrine systempchs.psd202.org/documents/dpohlman/1515513237.pdfimmune system long-term stress...
TRANSCRIPT
PowerPoint® Lecture Slide Presentation
by Patty Bostwick-Taylor,
Florence-Darlington Technical College
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
PART B9
The Endocrine
System
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Thyroid Gland
Found at the base of the throat
Consists of two lobes and a connecting isthmus
Produces two hormones
Thyroid hormone
Calcitonin
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Thyroid Gland
Figure 9.7a
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Thyroid Gland
Thyroid hormone
Major metabolic hormone
Composed of two active iodine-containing
hormones
Thyroxine (T4)—secreted by thyroid
follicles
Triiodothyronine (T3)—conversion of T4 at
target tissues
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Thyroid Gland
Figure 9.7b
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Thyroid Gland
Thyroid hormone disorders
Goiters
Thyroid gland enlarges due to lack of
iodine
Salt is iodized to prevent goiters
Cretinism
Caused by hyposecretion of thyroxine
Results in dwarfism during childhood
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Thyroid Gland
Figure 9.8
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Thyroid Gland
Goiter
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Cretinism
True cretinism can only be avoided by an adequate iodine intake through gestation. This simply requires substituting all household salt, and that available to domestic animals, with iodized salt, containing 1.34 μg KI/kg salt.
The misnamed ‘sporadic’ cretins, on the other hand, identified by neonatal screening programs, require prompt postnatal treatment with thyroid hormones to prevent their mental retardation.
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Thyroid Gland
Cretinism
Baby before and after radioactive treatment for sporadic cretinism
Sporadic Cretinism
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Thyroid Gland
Thyroid hormone disorders (continued)
Myxedema
Caused by hypothyroidism in adults
Results in physical and mental slugishness
Graves’ disease
Caused by hyperthyroidism
Results in increased metabolism, heat intolerance, rapid heartbeat, weight loss, and exophthalmos
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Myxedema
Man with myxedema or severe hypothyroidism showing an expressionless face, puffiness around the eyes and pallor
Additional finding include swelling of the arms and legs and significant ascites.
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Thyroid Gland
Figure 9.9
Graves’ disease
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Graves’ disease
Showing eye bulge and goiter
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Thyroid Gland
Calcitonin
Decreases blood calcium levels by causing its
deposition on bone
Antagonistic to parathyroid hormone
Produced by parafollicular cells
Parafollicular cells are found between the
follicles
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Thyroid Gland
Figure 9.7b
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Parathyroid Glands
Tiny masses on the posterior of the thyroid
Secrete parathyroid hormone (PTH)
Stimulate osteoclasts to remove calcium from
bone
Stimulate the kidneys and intestine to absorb
more calcium
Raise calcium levels in the blood
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Parathyroid Glands
Parathyroid hormone disorder
Tetany
If blood calcium levels fall too low,
neurons become extremely irritable
and over active. Impulses to muscles
are so fast that muscles go into
uncontrollable spasms called tetany,
which can be fatal.
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Hormonal Regulation of Calcium in Blood
Figure 9.10
Calcium homeostasis of blood9–11 mg/100 ml
RisingbloodCa2+
levels
Thyroid glandreleasescalcitonin
Osteoclastsdegrade bonematrix and releaseCa2+ into blood
PTH
Calcitonin Calcitoninstimulatescalcium saltdepositin bone
Parathyroidglands releaseparathyroidhormone (PTH)
Thyroidgland
Thyroidgland
Parathyroidglands
FallingbloodCa2+
levels
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Hormonal Regulation of Calcium in Blood
Figure 9.10, step 1
Calcium homeostasis of blood9–11 mg/100 ml
Rising
blood
Ca2+
levels
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Hormonal Regulation of Calcium in Blood
Figure 9.10, step 2
Calcium homeostasis of blood9–11 mg/100 ml
Rising
blood
Ca2+
levels
Thyroid
gland
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Hormonal Regulation of Calcium in Blood
Figure 9.10, step 3
Calcium homeostasis of blood9–11 mg/100 ml
Rising
blood
Ca2+
levels
Thyroid gland
releases
calcitonin
Calcitonin
Thyroid
gland
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Hormonal Regulation of Calcium in Blood
Figure 9.10, step 4
Calcium homeostasis of blood9–11 mg/100 ml
Rising
blood
Ca2+
levels
Thyroid gland
releases
calcitonin
Calcitonin Calcitonin
stimulates
calcium salt
deposit
in bone
Thyroid
gland
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Hormonal Regulation of Calcium in Blood
Figure 9.10, step 5
Calcium homeostasis of blood9–11 mg/100 ml
Rising
blood
Ca2+
levels
Thyroid gland
releases
calcitonin
Calcitonin Calcitonin
stimulates
calcium salt
deposit
in bone
Thyroid
gland
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 9.10, step 6
Calcium homeostasis of blood9–11 mg/100 ml
Falling
blood
Ca2+
levels
Hormonal Regulation of Calcium in Blood
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 9.10, step 7
Calcium homeostasis of blood9–11 mg/100 ml
Thyroid
gland
Parathyroid
glands
Falling
blood
Ca2+
levels
Hormonal Regulation of Calcium in Blood
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 9.10, step 8
Calcium homeostasis of blood9–11 mg/100 ml
PTHParathyroid
glands release
parathyroid
hormone (PTH)
Thyroid
gland
Parathyroid
glands
Falling
blood
Ca2+
levels
Hormonal Regulation of Calcium in Blood
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 9.10, step 9
Calcium homeostasis of blood9–11 mg/100 ml
Osteoclasts
degrade bone
matrix and release
Ca2+ into blood
PTHParathyroid
glands release
parathyroid
hormone (PTH)
Thyroid
gland
Parathyroid
glands
Falling
blood
Ca2+
levels
Hormonal Regulation of Calcium in Blood
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 9.10, step 10
Calcium homeostasis of blood9–11 mg/100 ml
Osteoclasts
degrade bone
matrix and release
Ca2+ into blood
PTHParathyroid
glands release
parathyroid
hormone (PTH)
Thyroid
gland
Parathyroid
glands
Hormonal Regulation of Calcium in Blood
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 9.10, step 11
Calcium homeostasis of blood9–11 mg/100 ml
RisingbloodCa2+
levels
Thyroid glandreleasescalcitonin
Osteoclastsdegrade bonematrix and releaseCa2+ into blood
PTH
Calcitonin Calcitoninstimulatescalcium saltdepositin bone
Parathyroidglands releaseparathyroidhormone (PTH)
Thyroidgland
Thyroidgland
Parathyroidglands
FallingbloodCa2+
levels
Hormonal Regulation of Calcium in Blood
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Adrenal Glands
Sit on top of the kidneys
Two regions
Adrenal cortex—outer glandular region has
three layers
Mineralocorticoids secreting area
Glucocorticoids secreting area
Sex hormones secreting area
Adrenal medulla—inner neural tissue region
Catecholamines secreting area
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Hormones of the Adrenal Cortex
Figure 9.11
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Hormones of the Adrenal Cortex
Mineralocorticoids (mainly aldosterone)
Produced in outer adrenal cortex
Regulate mineral content in blood
Regulate water and electrolyte balance
Target organ is the kidney
Production stimulated by renin (kidney) and
aldosterone
Production inhibited by atrial natriuretic
peptide (ANP) (heart)
Rising blood levels of aldosterone cause
kidney tubules to reabsorb sodium
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Hormones of the Adrenal Cortex
Figure 9.12
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Hormones of the Adrenal Cortex
Glucocorticoids (including cortisone and cortisol)
Produced in the middle layer of the adrenal
cortex
Promote normal cell metabolism
Help resist long-term stressors
Released in response to increased blood
levels of ACTH
Suppress inflammation, decrease edema and
increase blood glucose levels
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Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13
Short term More prolongedStress
Hypothalamus
Nerve impulses
Adrenal
cortex
Releasing hormone
Corticotropic cells ofanterior pituitary
ACTH
Mineralocorticoids Glucocorticoids
1. Retention of sodium
and water by kidneys
2. Increased blood
volume and blood
pressure
1. Proteins and fats
converted to glucose
or broken down for
energy
2. Increased blood
sugar
3. Suppression of
immune system
Long-term stress response
Short-term
stress response
Spinal cord
Adrenal
medulla
Preganglionicsympatheticfibers
Catecholamines(epinephrine andnorepinephrine)
1. Increased heart rate
2. Increased blood pressure
3. Liver converts glycogen to
glucose and releases glucose
to blood
4. Dilation of bronchioles
5. Changes in blood flow
patterns, leading to increased
alertness and decreased
digestive and kidney activity
6. Increased metabolic rate
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Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13, step 1
Short term Stress
Hypothalamus
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Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13, step 2
Short term Stress
Hypothalamus
Nerve impulses
Spinal cord
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Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13, step 3
Short term Stress
Hypothalamus
Nerve impulses
Spinal cord
Adrenal
medulla
Preganglionicsympatheticfibers
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Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13, step 4
Short term Stress
Hypothalamus
Nerve impulses
Short-term
stress response
Spinal cord
Adrenal
medulla
Preganglionicsympatheticfibers
Catecholamines(epinephrine andnorepinephrine)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13, step 5
Short term Stress
Hypothalamus
Nerve impulses
Short-term
stress response
Spinal cord
Adrenal
medulla
Preganglionicsympatheticfibers
Catecholamines(epinephrine andnorepinephrine)
1. Increased heart rate
2. Increased blood pressure
3. Liver converts glycogen to
glucose and releases glucose
to blood
4. Dilation of bronchioles
5. Changes in blood flow
patterns, leading to increased
alertness and decreased
digestive and kidney activity
6. Increased metabolic rate
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Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13, step 6
More prolongedStress
Hypothalamus
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13, step 7
More prolongedStress
Hypothalamus
Releasing hormone
Corticotropic cells ofanterior pituitary
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13, step 8
More prolongedStress
Hypothalamus
Adrenal
cortex
Releasing hormone
Corticotropic cells ofanterior pituitary
ACTH
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13, step 9
More prolongedStress
Hypothalamus
Adrenal
cortex
Releasing hormone
Corticotropic cells ofanterior pituitary
ACTH
Mineralocorticoids
Long-term stress response
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13, step 10
More prolongedStress
Hypothalamus
Adrenal
cortex
Releasing hormone
Corticotropic cells ofanterior pituitary
ACTH
Mineralocorticoids Glucocorticoids
Long-term stress response
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13, step 11
More prolongedStress
Hypothalamus
Adrenal
cortex
Releasing hormone
Corticotropic cells ofanterior pituitary
ACTH
Mineralocorticoids Glucocorticoids
1. Retention of sodium
and water by kidneys
2. Increased blood
volume and blood
pressure
Long-term stress response
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13, step 12
More prolongedStress
Hypothalamus
Adrenal
cortex
Releasing hormone
Corticotropic cells ofanterior pituitary
ACTH
Mineralocorticoids Glucocorticoids
1. Retention of sodium
and water by kidneys
2. Increased blood
volume and blood
pressure
1. Proteins and fats
converted to glucose
or broken down for
energy
2. Increased blood
sugar
3. Suppression of
immune system
Long-term stress response
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Roles of the Hypothalamus and
Adrenal Glands in the Stress Response
Figure 9.13, step 13
Short term More prolongedStress
Hypothalamus
Nerve impulses
Adrenal
cortex
Releasing hormone
Corticotropic cells ofanterior pituitary
ACTH
Mineralocorticoids Glucocorticoids
1. Retention of sodium
and water by kidneys
2. Increased blood
volume and blood
pressure
1. Proteins and fats
converted to glucose
or broken down for
energy
2. Increased blood
sugar
3. Suppression of
immune system
Long-term stress response
Short-term
stress response
Spinal cord
Adrenal
medulla
Preganglionicsympatheticfibers
Catecholamines(epinephrine andnorepinephrine)
1. Increased heart rate
2. Increased blood pressure
3. Liver converts glycogen to
glucose and releases glucose
to blood
4. Dilation of bronchioles
5. Changes in blood flow
patterns, leading to increased
alertness and decreased
digestive and kidney activity
6. Increased metabolic rate
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Hormones of the Adrenal Cortex
Sex hormones
Produced in the inner layer of the adrenal
cortex
Small amounts are made throughout life
Mostly androgens (male sex hormones) are
made but some estrogens (female sex
hormones) are also formed
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Adrenal Glands
Adrenal cortex disorders
Addison’s disease
Results from hyposecretion of ALL
adrenal cortex hormones
Bronze skin tone, muscles are weak,
burnout, susceptibility to infection
Hyperaldosteronism
May result from an ACTH-releasing tumor
Excess water and sodium are retained
leading to high blood pressure and edema
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Adrenal Glands
Addison’s disease
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Adrenal Glands
Adrenal cortex disorders
Cushing’s syndrome
Results from a tumor in the middle cortical area of the adrenal cortex (glucocorticoids)
“Moon face,” “buffalo hump” on the upper back, high blood pressure, hyperglycemia, weakening of bones, depression
Masculinization
Results from hypersecretion of sex hormones
Beard and male distribution of hair growth
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Adrenal Glands
Cushing’s syndrome
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Cushing’s syndrome
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Hormones of the Adrenal Medulla
Produces two similar hormones (catecholamines)
Epinephrine (adrenaline)
Norepinephrine (noradrenaline)
These hormones prepare the body to deal with
short-term stress (“fight or flight”) by
Increasing heart rate, blood pressure, blood
glucose levels
Dilating small passageways of lungs
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Hormones of the Adrenal Cortex
Figure 9.11
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Pancreatic Islets
The pancreas is a mixed gland and has both
endocrine and exocrine functions
The pancreatic islets produce hormones
Insulin—produced from beta cells of islets.
Allows glucose to cross plasma membranes into
cells thus decreasing blood glucose levels.
Glucagon—produced from alpha cells of islets.
Breaks down glycogen in the liver to allow
glucose to enter the blood, thus raising blood
sugar.
These hormones are antagonists that maintain
blood sugar homeostasis
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Pancreatic Islets
Figure 9.14a–b
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Pancreatic Islets
Figure 9.14b–c
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Pancreatic Islets
Insulin hormone disorder
Diabetes mellitus
Blood glucose raises and spills into urine
causing water to follow. Urine smells sweet.
Can cause acidosis when fat has to be used
for energy.
3 signs:
Polyuria- excessive urination
Polydipsia- excessive thirst
Polyphagia- excessive hunger
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Figure 9.15
Insulin-secretingcells of the pancreasactivated; releaseinsulin into theblood
Elevatedblood sugarlevels
Stimulus:rising bloodglucose levels(e.g., aftereating fourjelly doughnuts)
Rising bloodglucose levelsreturn blood sugarto homeostatic setpoint; stimulus forglucagon releasediminishes
Blood glucoselevels declineto set point;stimulus forinsulin releasediminishes
Stimulus:declining bloodglucose levels(e.g., afterskipping a meal)
Low bloodsugar levels
Glucagon-releasingcells of pancreasactivated;release glucagoninto blood; targetis the liver
Uptake of glucosefrom blood is en-hanced in mostbody cells
Liver breaks downglycogen stores andreleases glucose tothe blood
Liver takes upglucose and storesit as glycogen
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
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Figure 9.15, step 1
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Stimulus:
rising blood
glucose levels
(e.g., after
eating four
jelly doughnuts)
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
Figure 9.15, step 2
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Elevated
blood sugar
levels
Stimulus:
rising blood
glucose levels
(e.g., after
eating four
jelly doughnuts)
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
Figure 9.15, step 3
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Insulin-secreting
cells of the pancreas
activated; release
insulin into the
blood
Elevated
blood sugar
levels
Stimulus:
rising blood
glucose levels
(e.g., after
eating four
jelly doughnuts)
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
Figure 9.15, step 4
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Insulin-secreting
cells of the pancreas
activated; release
insulin into the
blood
Elevated
blood sugar
levels
Stimulus:
rising blood
glucose levels
(e.g., after
eating four
jelly doughnuts)
Uptake of glucose
from blood is en-
hanced in most
body cells
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
Figure 9.15, step 5
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Insulin-secreting
cells of the pancreas
activated; release
insulin into the
blood
Elevated
blood sugar
levels
Stimulus:
rising blood
glucose levels
(e.g., after
eating four
jelly doughnuts)
Uptake of glucose
from blood is en-
hanced in most
body cells
Liver takes up
glucose and stores
it as glycogen
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
Figure 9.15, step 6
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 9.15, step 7
Insulin-secreting
cells of the pancreas
activated; release
insulin into the
blood
Elevated
blood sugar
levels
Stimulus:
rising blood
glucose levels
(e.g., after
eating four
jelly doughnuts)
Blood glucose
levels decline
to set point;
stimulus for
insulin release
diminishes
Uptake of glucose
from blood is en-
hanced in most
body cells
Liver takes up
glucose and stores
it as glycogen
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 9.15, step 8
Stimulus:
declining blood
glucose levels
(e.g., after
skipping a meal)
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 9.15, step 9
Stimulus:
declining blood
glucose levels
(e.g., after
skipping a meal)
Low blood
sugar levels
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 9.15, step 10
Stimulus:
declining blood
glucose levels
(e.g., after
skipping a meal)
Low blood
sugar levels
Glucagon-releasing
cells of pancreas
activated;
release glucagon
into blood; target
is the liver
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 9.15, step 11
Stimulus:
declining blood
glucose levels
(e.g., after
skipping a meal)
Low blood
sugar levels
Glucagon-releasing
cells of pancreas
activated;
release glucagon
into blood; target
is the liverLiver breaks down
glycogen stores and
releases glucose to
the blood
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 9.15, step 12
Rising blood
glucose levels
return blood sugar
to homeostatic set
point; stimulus for
glucagon release
diminishes
Stimulus:
declining blood
glucose levels
(e.g., after
skipping a meal)
Low blood
sugar levels
Glucagon-releasing
cells of pancreas
activated;
release glucagon
into blood; target
is the liverLiver breaks down
glycogen stores and
releases glucose to
the blood
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 9.15, step 13
Insulin-secretingcells of the pancreasactivated; releaseinsulin into theblood
Elevatedblood sugarlevels
Stimulus:rising bloodglucose levels(e.g., aftereating fourjelly doughnuts)
Rising bloodglucose levelsreturn blood sugarto homeostatic setpoint; stimulus forglucagon releasediminishes
Blood glucoselevels declineto set point;stimulus forinsulin releasediminishes
Stimulus:declining bloodglucose levels(e.g., afterskipping a meal)
Low bloodsugar levels
Glucagon-releasingcells of pancreasactivated;release glucagoninto blood; targetis the liver
Uptake of glucosefrom blood is en-hanced in mostbody cells
Liver breaks downglycogen stores andreleases glucose tothe blood
Liver takes upglucose and storesit as glycogen
Homeostasis: Normal blood glucose
levels (90 mg/100ml)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Pineal Gland
Found on the third ventricle of the brain
Secretes melatonin
Helps establish the body’s wake and sleep
cycles
Believed to coordinate the hormones of
fertility in humans
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Location of Major Endrocrine Organs
Figure 9.3
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Thymus Gland
Located posterior to the sternum
Largest in infants and children
Produces thymosin
Matures some types of white blood cells
known as T lymphocytes (T-cells)
Important in developing the immune system
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Gonads
Ovaries
Produce eggs
Produce two groups of steroid hormone
Estrogens
Progesterone
Testes
Produce sperm
Produce androgens, such as testosterone
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Location of Major Endrocrine Organs
Figure 9.3
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Hormones of the Ovaries
Estrogens
Stimulate the development of secondary
female characteristics
Mature female reproductive organs
With progesterone, estrogens also
Promote breast development
Regulate menstrual cycle
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Hormones of the Ovaries
Progesterone (produced along with estrogen by
the ruptured egg follicle called the corpus luteum
or “yellow body”)
Acts with estrogen to bring about the
menstrual cycle
Helps in the implantation of an embryo in the
uterus and quiets the muscles of the uterus
Helps prepare breasts for lactation
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Hormones of the Testes
Produce several androgens
Testosterone is the most important androgen
Responsible for adult male secondary sex
characteristics
Promotes growth and maturation of male
reproductive system
Required for sperm cell production
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Other Hormone-Producing Tissues and Organs
Parts of the small intestine
Parts of the stomach
Kidneys
Heart
Many other areas have scattered endocrine cells
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Other Hormone-Producing Tissues and Organs
Table 9.2 (1 of 2)
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Table 9.2 (2 of 2)
Other Hormone-Producing Tissues and Organs
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Endocrine Function of the Placenta
Produces hormones that maintain the pregnancy
Some hormones play a part in the delivery of the
baby
Produces human chorionic gonadotropin (hCG) in
addition to estrogen, progesterone, and other
hormones
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Developmental Aspects of the Endocrine System
Most endocrine organs operate smoothly until old
age
Menopause is brought about by lack of
efficiency of the ovaries
Problems associated with reduced estrogen
are common
Growth hormone production declines with age
Many endocrine glands decrease output with
age