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Figure 18-7 The Hypophyseal Portal System and the Blood Supply to the Pituitary Gland

Supraopticnuclei

Paraventricularnuclei

Neurosecretoryneurons

HYPOTHALAMUS

MEDIAN

EMINENCE

Opticchiasm

Capillarybeds

ANTERIOR LOBEOF PITUITARY GLAND

Mamillary body

Superior hypophyseal artery

Infundibulum

Portal vessels

Inferior hypophyseal artery

POSTERIOR LOBEOF PITUITARY GLAND

Endocrine cells

Hypophyseal veins

Hyp

otha

lam

us: t

he m

aste

r gl

and

p. 605

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Figure 18-8a Feedback Control of Endocrine Secretion

Endocrinetargetorgan

Hormone 2(from targetorgan)

TRH

CRH

GnRH

TSH

ACTH

FSH

LH

Thyroidgland

Adrenalcortex

Ovaries

Testes

Thyroidhormones

Gluco-corticoids

Inhibin

InhibinEstrogens

ProgestinsEstrogens

Androgens

Releasinghormone(RH)

Hormone 1(frompituitary)

Ovaries

Testes

Negative feedback

Hypothalamus

RH

Pituitarygland

Anteriorlobe

Hormone 1

Endocrineorgan

Hormone 2

Target cells

KEY

Stimulation

Inhibition

p. 606

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Figure 18-8b Feedback Control of Endocrine Secretion

Stimulatesmammary

glands

Liver

Epithelia,adipose tissue,liver

Stimulates growth of skeletal muscle,cartilage, and many other tissues

Stimulation

Inhibition

Stimulation

Inhibition

Anteriorlobe

Anteriorlobe

Somatomedins

GH–IH

GH–RH

GHPRL

PRF

PIH

p. 606

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Figure 18-9 Pituitary Hormones and Their Targets

InhibinProgesteroneEstrogenTestosteroneInhibin

Thyroidhormones (T3, T4)

Glucocorticoids(cortisol,

corticosterone)

Epinephrine andnorepinephrine

Adrenalgland

Adrenalmedulla

Adrenalcortex

Thyroidgland

Bone, muscle,other tissues Mammary

glands

Testesof male

Ovariesof female

Melanocytes (uncertainsignificance in healthyadults)

Somatomedins

Liver MSHLHFSHPRL

GHTSH

ACTH

Anterior lobe ofpituitary gland

ACTHTSHGH

PRLFSHLH

MSH

OXTADH

Adrenocorticotropic hormoneThyroid-stimulating hormoneGrowth hormoneProlactinFollicle-stimulating hormone

Luteinizing hormoneMelanoctye-stimulating hormoneAntidiuretic hormone

Oxytocin

KEY TO PITUITARY HORMONES:

Regulatory hormones are releasedinto the hypophyseal portal systemfor delivery to the anterior lobe ofthe pituitary gland

Indirect Control through Releaseof Regulatory Hormones

Direct Controlby NervousSystem

Hypothalamus

p. 609

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Figure 18-9 Pituitary Hormones and Their Targets

Females: Uterinesmooth muscle andmammary glands

Males: Smoothmuscle in ductusdeferens andprostate gland

Kidneys

ADH

OXT

Posterior lobeof pituitary gland

ACTHTSHGH

PRLFSHLH

MSH

OXTADH

Adrenocorticotropic hormoneThyroid-stimulating hormoneGrowth hormoneProlactinFollicle-stimulating hormoneLuteinizing hormoneMelanoctye-stimulating hormoneAntidiuretic hormoneOxytocin

KEY TO PITUITARY HORMONES:

Direct Releaseof Hormones

Sensorystimulation

Osmoreceptorstimulation

p. 609

Hypothalamus: the master gland

p. 619Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

© 2012 Pearson Education, Inc.

© 2012 Pearson Education, Inc.

Figure 18-10a The Thyroid Gland

Hyoid bone

Superiorthyroid artery

Thyroid cartilageof larynx

Superiorthyroid vein

Commoncarotid artery

Right lobe ofthyroid gland

Middle thyroid vein

Thyrocervical trunk

Trachea

Internaljugular vein

Cricoid cartilageof larynx

Left lobe ofthyroid gland

Isthmus ofthyroid gland

Inferiorthyroid artery

Inferiorthyroidveins

Outline of clavicle

Outline of sternum

Location and anatomy of the thyroid gland

p. 611

© 2012 Pearson Education, Inc.

Figure 18-10c The Thyroid Gland

LM 260Follicles of the thyroid gland

Thyroidfollicle

Capillary

Thyroidfollicle

Capsule

Folliclecavities

C cell

C cell

Cuboidalepithelium

of follicle

Thyroglobulinstored in colloid

of follicle

Histological details of the thyroid gland showing thyroid follicles and both of the celltypes in the follicular epithelium ATLAS: Plate 18c

p. 611

© 2012 Pearson Education, Inc.

Figure 18-11a The Thyroid Follicles

Folliclecavity

Thyroglobulin(contains T3 and T4)

FOLLICLE CAVITY

Endocytosis

Lysosomaldigestion

Thyroglobulin

Other amino acids

Tyrosine

Diffusion

DiffusionTSH-sensitiveion pump FOLLICLE CELL

CAPILLARY

Iodide (I–)

T4 & T3

TBG, transthryretin,or albumin

The synthesis, storage, and secretion of thyroid hormones.

Iodide(I+)

T4T3

p. 612

© 2012 Pearson Education, Inc.

Figure 18-11b The Thyroid Follicles

The regulation of thyroid secretion

HomeostasisDisturbed

HOMEOSTASIS

HomeostasisRestored

Thyroid folliclesrelease T3 and T4

Thyroidgland

TSH

Anteriorlobe

Pituitarygland

Hypothalamusreleases TRH

TRH

Anteriorlobe

Decreased T3 and T4 concentrationsin blood or lowbody temperature

Normal T3 and T4 concentrations,

normal bodytemperature

Increased T3 and T4 concentrationsin blood

p. 612

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p. 601

The Thyroid Gland

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings © 2012 Pearson Education, Inc.

p. 613

© 2012 Pearson Education, Inc.

Figure 18-10c The Thyroid Gland

LM 260Follicles of the thyroid gland

Thyroidfollicle

Capillary

Thyroidfollicle

Capsule

Folliclecavities

C cell

C cell

Cuboidalepithelium

of follicle

Thyroglobulinstored in colloid

of follicle

Histological details of the thyroid gland showing thyroid follicles and both of the celltypes in the follicular epithelium ATLAS: Plate 18c

p. 611

© 2012 Pearson Education, Inc.

Figure 18-12a The Parathyroid Glands

Left lobe ofthyroid gland

Parathyroidglands

Posterior view of the thyroid gland showing the parathyroid glands. p. 614

© 2012 Pearson Education, Inc.

Figure 18-12c The Parathyroid Glands

Parathyroid gland cells

Parathyroid cells and oxyphil cells

Oxyphilcells

Parathyroid(chief) cells

LM 600

p. 614

© 2012 Pearson Education, Inc.

Figure 18-13 The Homeostatic Regulation of Calcium Ion Concentrations

Increasedexcretionof calciumby kidneys

Calciumdeposition

in bone

HOMEOSTASISRESTORED

Blood calciumlevels decline

Thyroid glandproducescalcitonin

Ris

ing

lev

els

of

blo

od

cal

ciu

m

HOMEOSTASISDISTURBED

Rising calciumlevels in blood

HOMEOSTASIS

Normal bloodcalcium levels(8.5–11 mg/dL) p. 615

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Figure 18-13 The Homeostatic Regulation of Calcium Ion Concentrations

HOMEOSTASIS

Normal bloodcalcium levels(8.5–11 mg/dL)

HOMEOSTASISRESTORED

Blood calciumlevels increase

HOMEOSTASISDISTURBED

Falling calciumlevels in blood

Fal

ling

leve

ls o

f b

loo

d c

alci

um

Parathyroidglands secreteparathyroidhormone (PTH)

Increasedreabsorption ofcalcium bykidneys

Calcium releasefrom bone

Increased calcitriolproduction causesCa2+ absorptionby digestivesystem

p. 615

© 2012 Pearson Education, Inc.

Figure 18-15 The Pineal Gland

Pineal gland LM 450

Pinealocytes

p. 619

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings © 2012 Pearson Education, Inc.