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Topic 17: Endocrine Integration
� What is endocrine integration?
� What glands are included?
� What is the hypothalamo-hypophyseal axis?
� Development, Morphology & Function
� How does the hypothalamo-hypophyseal axis regulate
other endocrine organs?
� What is the pineal gland and what does it do?
� What are the adrenal glands and what do they do?
� How is metabolism regulated?
� Thyroid glands
� Pancreatic islets, insulin and diabetes
What is Endocrine Integration?
� Endocrine glands secrete hormones
� Hormones signal cells all over the body
� Allows longer term response to stimuli
� Multiple targets respond to same signal
© Web-books.com
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What is Endocrine
Integration?
Liem et al. Fig. 15-1
Nervous Endocrine
Effect Time
Effect Area
Activa-tion
Signal
Signal Conduit
Target
What glands are included?
� Endocrine glands are distributed throughout the body
� Many developmental origins
� All secrete ______________
Liem et al. Fig. 15-2
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How do hormones work?
� How hormones work� Lock & key mechanism
� Bind to receptor
� Signalling cascade -________________
� Gene transcription -________________
� _________________1. Water soluble, can’t
cross plasma membrane
2. Bind membrane receptor
3. Initiate signaling cascade
4. Activate enzymes
Liem et al. Fig. 15-3
1 & 2
3
4
Glands & Hormones
_________________1. Lipid soluble hormones
(steroids)
2. Need carrier in blood
3. Enter cell
4. Bind to receptor
5. Hormone-receptor complex enters nucleus
6. H-r binds to acceptor on chromosome
7. Initiates gene transcription
8. Protein synthesis
Liem et al. Fig. 15-3
Gene
Transcription
8
7
6
543
1 & 2
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What is the
Hypothalamo-Hypophyseal Axis?
Liem et al. Fig. 15-2, 15-4
� _________________ for endocrine system
� ___________ of the brain
� Neural ectoderm
� ___________ of the brain
� Neurohypophysis
� Neural ectoderm
� Adenohypophysis
� Epidermal ectoderm
What is the
Hypothalamo-Hypophyseal Axis?
� ________________ (posterior pituitary)
� Infundibular stalk
� Pars nervosa
� ________________ (anterior pituitary)
� Pars tuberalis
� Pars intermedia
� Pars distalis
Liem et al. Fig. 15-4; © education.vetmed.vt.edu
What does the
Hypothalamo-Hypophyseal Axis do?
Liem et al. Fig. 15-4NeurohypophysisAdenohypophysisHypothalamus
• TRH – Thyrotropin RH
• GnRH – Gonadotropin RH
• Prolactin RH
• Corticotropin RH
• Melanotropin RH
• Growth Hormone RIH
• Prolactin RIH
• Melanotropin RIH
• Somatocrinin
• Releasing Hormones (RH)
• Release Inhibiting
Hormones (RIH)
• VP – Vasopressin
• OXY - Oxytocin
• GH – Growth Hormone
• PRL – Prolactin
• MSH - Melanotropin
• TSH – Thyrotropin
• FSH – Follicle stimul. H
• LH – Luteinizing Hormone
• ACTH – Corticotropin
Stimulation & Inhibition of Adenohypophysis
Somatic Endocrine
Target Tissues
Somatic Non-Endocrine
Target Tissues
What does the
Hypothalamo-Hypophyseal Axis do?
Liem et al. Fig. 15-4, Table 15-1
Hypothalamus
Somatic Endocrine
Target Tissues
Hypothalamus Hypophysis Target Tissue Target Action
Thyrotropin RH Thyrotropin Thyroid Thyroid H Secretion
Somatocrinin Growth Hormone
BodyProtein Synthesis,
GrowthGrowth Hor. RIH
Prolactin RHProlactin
Body, Reproductive
Tissues
Milk Synthesis, Growth, Reprod, Water BalanceProlactin RIH
Melanotropin RHMelanotropin Skin
Melanin synthesis & DispersalMelanotropin RIH
Gonadotropin RHFollicle SH & Luteninizing H
GonadsOvar. Follicle &
Seminiferous Tub. Development
Corticotropin RH Corticotropin Adrenal Glands Adrenal H Release
Vasopressin Kidney Urine Production
Oxytocin♀ Reprod.
Tissues
Uterine MuscleContraction
Adenophyophysis
Somatic Non-Endocrine
Target Tissues
Neurohypophysis
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What is the Pineal Gland and what does it do?
� What has this gland evolved from?
� Circadian rhythms, regulation of sleep
� Secretion of _________________ from
pinealocytes� Response to photocycle
� Inhibition by light, sensed by eyes
� ________________� From eye
� Suprachiasmatic nucleus of hypothalamus acts as biological clock
� Neurons to pineal gland
Liem et al. Fig. 15-6
How have Adrenal
Glands evolved?
� Associated with kidneys
Evolution:
1. ____________ tissue
2. ____________ tissue
3. Cortical tissue islets
4. ____________ glands
5. Multiple adrenal glands
6. One pair of adrenal
glands
7. Distinct medulla & cortex
Liem et al. Fig. 15-9
Lamprey
Bowfin
Shark
Teleost
Lungfish
Salamander
Lizard
Bird
Mammal7
6
5
4
3
2
1
What are the Adrenal Glands?
� __________________� Chromaffin cells
� Neural stimulation to release norepinephrin & epinephrin
� Act on Sympathetic NS
� Released during times of stress
� _________________� Periferal
� Corticotropin stimulates release of glucocorticoids
� Cortisol
� Corticosterone
� Inhibit blood glucose use, diverting glucose to CNS
© web-books.com; education.vetmed/vt/edu
Adrenal Feedback
� Control through negative feedback
� Response to ______________
� __________: uptake of amino
acids, conversion to glucose
� __________: prevent glucose uptake, mobilization of amino acids
� Mobilization of fat stores
Liem et al. Fig. 15-4; web-books.com; exercisemenu.com; zdsolution.it; musclehelp.com
Liver Muscles Adipose
STRESSCorticotropin RH
Corticotropin
Glucocorticoids-
+
+
How is Metabolism regulated?
� _______________
� Highly vascularized
� Follicles secrete colloid
� Secretes thyroglobulin
� Thyroglobulin & iodine
used to produce:
� Triiodothionine (T3)
� Thyroxin (T4)
© education.vetmed.vt.edu; gopetsamerica.com
� ________________
� Exocrine (digestion)
� Endocrine – Islets of
Langerhans
� Production of
� Insulin
� Glucagon
How does the thyroid
regulate metabolism?
� Stimulation of Thyrotropin RH:
� _______________
� _______________________
� T3 & T4 increase metabolic rate in:
� heart
� liver
� muscle
� kidney
Liem et al. Fig. 15-4; web-books.com;
zdsolution.it; musclehelp.com; ynhh.org; ADAM
Liver MusclesHeart
Thyroid
Kidney
Thyrotropin RH
Triiodothrionine
Thyroxine
Thyrotropin
- +
-
+
+
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Thyroid Disorders
� ___________________
� Iodine deficiency
compensation
� Thyroid hypertrophy
� Weight gain or difficult to lose weight
� ________________
� developmental hypothyroidism
� Mental retardation
� __________________
� More rare
� Weight loss
� Restlessness
� Difficulty concentrating
© learningradiology.com; wordpress.com
How does the pancreas
regulate metabolism?
� Pancreas
� ______________________
� Secrete hormones of opposing effects
� ___________
� Decreases blood glucose
� ___________
� Increases blood glucose
© Getty Images, tutorvista.com
Liver Muscles Kidney
All
Tissues
Insulin+
Low Blood
Glucose
High Blood
Glucose
Glucagon+
+
© tutorvista.com; web-books.com; zdsolution.it; musclehelp.com
How does the pancreas
regulate metabolism?
� Insulin: Decreases blood glucose
� Increased glycogen synthesis
� Glucose absorption by kidneys
� Suppression of glycogen breakdown
� Glucagon: Increases blood glucose
� Breakdown of glycogen in liver
Diabetes
� High blood glucose
� Glucose not being used by tissues
� Excreted in urine instead
� Protein & fat used for energy
� ____________ Diabetes
� Failure to produce insulin
� Insulin injections to control blood
glucose
� ____________ Diabetes
� Insulin receptors are insulin-resistant
� Includes adult onset diabetes
� ____________ Diabetes
� Mother diabetic during pregnancy
� Can develop into Type II later in life
� Must control diet during pregnancy
