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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