dr. b ch 19_lecture_presentation

© 2012 Pearson Education, Inc.

19The Endocrine System

PowerPoint® Lecture Presentations prepared bySteven BassettSoutheast Community College Lincoln, Nebraska


Introduction

• The nervous system and the endocrinesystem work together to monitor thebody’s activities

• The nervous system: produces short-term, very specific responses

• The endocrine system: many times it produces long-term, general responses


Introduction

• The endocrine system releases chemicalscalled hormones

• Hormones leave a gland or gland-like structure• The hormone enters into the bloodstream• Hormones are organized into four groups

based on chemical structure: • Amino acid derivatives • Peptide hormones• Steroid hormones• Eicosanoids


An Overview of the Endocrine System

• The main endocrine organs are:• Pituitary gland• Hypothalamus • Thyroid gland• Thymus gland• Suprarenal glands• Pineal gland• Parathyroid glands• Pancreas• Reproductive glands


Endocrine activity Endocrine activity is controlled by endocrine reflexes that are triggered by:

Humoral stimuli Hormonal stimuli Neural stimuli


Figure 19.1 The Endocrine System

KEY TO PITUITARY HORMONES

ACTHTSHGHPRLFSHLHMSHADH

Adrenocorticotropic hormoneThyroid-stimulating hormoneGrowth hormoneProlactinFollicle-stimulating hormoneLuteinizing hormoneMelanocyte-stimulating hormoneAntidiuretic hormone

Each suprarenal gland issubdivided into:Medulla: Epinephrine (E) Norepinephrine (NE)Cortex: Cortisol, corticosterone, aldosterone, androgens

Thymosins

Testis

Thyroxine (T4)Triiodothyronine (T3)Calcitonin (CT)

Pars distalis (anterior lobe): ACTH, TSH, GH, PRL, FSH, LH, and MSHNeurohypophysis(posterior lobe): Release of oxytocin and ADH

Suprarenal Glands

Thymus(Undergoes atrophyduring adulthood)

Thyroid Gland

Pituitary Gland

HypothalamusProduction of ADH,oxytocin, and regulatoryhormones

Pineal GlandMelatonin

Parathyroid Glands(on posterior surface ofthyroid gland)

Parathyroid hormone (PTH)

HeartNatriuretic peptides: Atrial natriuretic peptide (ANP) Brain natriuretic peptide (BNP)

Erythropoietin (EPO)Calcitriol(Chapters 19 and 26)

Kidney

Adipose Tissue

Digestive Tract

Pancreatic Islets

Gonads

LeptinResistin

Numerous hormones(detailed in Chapter 25)

Insulin, glucagon

Testes (male): Androgens (especially testosterone), inhibinOvaries (female): Estrogens, progestins, inhibinOvary


An Overview of the Endocrine System

• The Hypothalamus and Endocrine Regulation

• Hypothalamus functions via three mechanisms• Secretes regulatory hormones

• Secretes releasing hormones (RH)• Secretes inhibiting hormones (IH)

• Acts as an endocrine organ• Releases antidiuretic hormone and oxytocin to

the pituitary gland• Contains autonomic nervous system centers

• Exerts control over the suprarenal medulla


Figure 19.2 Hypothalamic Control over Endocrine Organs

HYPOTHALAMUS

Secretion ofregulatory hormonesto control activity ofpars distalis (anteriorlobe) of pituitary gland

Productionof ADH andoxytocin

Control of sympatheticoutput to suprarenalmedullae

Pars distalis(anterior lobe)

of pituitary gland

Neurohypophysis(posterior lobe)of pituitary gland

Medulla

Hormones secretedby pars distalis ofpituitary glandcontrol otherendocrine organs

Release ofADH andoxytocin

Secretion ofepinephrine andnorepinephrine

Suprarenal gland

Preganglionicmotor fibers


The Pituitary Gland

The pituitary gland, or hypophysis Neurohypophysis (posterior lobe)

ADH: is secreted in response to low blood volume or high electrolyte concentration in blood. It will raise the blood pressure and lower the electrolyte concentration.

Lack of ADH secretion will cause diabetes insipidus. Oxytocin

Adenohypophysis (anterior lobe) ACTH — adrenocorticotropic hormone TSH — thyroid-stimulating hormone GH — growth hormone PRL — prolactin FSH — follicle-stimulating hormone: stimulates egg development

and estrogen production in female. LH — luteinizing hormone


Figure 19.3a Gross Anatomy and Histological Organization of the Pituitary Gland and Its Subdivisions

Relationship of the pituitarygland to the hypothalamus

Medianeminence

Thirdventricle

Mamillarybody

HYPOTHALAMUS

Optic chiasm

Infundibulum

Diaphragmasellae

Parstuberalis

Parsdistalis

Parsintermedia

Neurohypophysis(posterior lobe)

Sphenoid(sella turcica)

Adenohypophysis(anterior lobe)


Figure 19.5 The Pituitary Gland and the Hypophyseal Portal System

ADENOHYPOPHYSISOF PITUITARY GLAND

NEUROHYPOPHYSISOF PITUITARY GLAND

MEDIAN

EMINENCE

HYPOTHALAMUS

Hypophyseal veins

Endocrine cells

Inferior hypophyseal artery

Infundibulum

Superior hypophyseal artery

Portal veins

Mamillarybody

Paraventricularnuclei

Supraopticnuclei

Opticchiasm

CapillaryBeds


Table 19.1 The Pituitary Hormones


Figure 19.4 Pituitary Hormones and Their Targets

HypothalamusDirect Release

of HormonesIndirect Control Through Release

of Regulatory HormonesDirect Controlby NervousSystem Sensory

stimulationOsmoreceptor

stimulationRegulatory hormones are released intothe hypophyseal portal system for delivery

to the anterior lobe of the pituitary

Posterior lobeof pituitary gland

Adenohypophysis ofpituitary glandMedulla

Cortex

Suprarenalgland

Thyroidgland

Epinephrine andnorepinephrine

Liver

Glucocorticoids(cortisol,

corticosterone)

Thyroidhormones (T3, T4)

Bone, muscle,other tissues Mammary

glands

Testesof male

Ovariesof female

TestosteroneInhibin Estrogen Progesterone Inhibin

Melanocytes (uncertainsignificance in healthyadults)

Females: Uterinesmooth muscle andmammary glands

Males: Smoothmuscle in ductusdeferens andprostate gland

Kidneys


ACTHTSH

GH

PRL

FSHLH

MSH

ADH

Adrenocorticotropic hormone

Thyroid-stimulating hormone

Growth hormone

Prolactin

Follicle-stimulating hormone

Luteinizing hormone

Melanocyte-stimulating hormone

Antidiuretic hormone

ADH

Oxytocin

MSH

LHFSHPRL

GHTSH

ACTH

Somatomedins


The Thyroid Gland

Sits on thyroid cartilage of larynx Butterfly-like appearance Consists of two main lobes connected by the isthmusThe only endocrine gland that stores its hormone extracellularly. Controls metabolism

Thyroxine (T4) Triiodothyronine (T3)

Involved in calcium homeostasis Calcitonin: decreases the concentration of

calcium in blood.


Figure 19.6a Anatomy and Histological Organization of the Thyroid Gland

Location and anatomy of the thyroid gland

Isthmus ofthyroid gland

Left lobe ofthyroid gland

Internaljugular vein

Cricoid cartilageof larynx

Inferiorthyroid artery

Inferiorthyroidveins

Superiorthyroid artery

Hyoid bone

Middle thyroid vein

Thyrocervical trunk

Trachea

Outline of clavicle

Outline of sternum

Thyroid cartilageof larynx

Superiorthyroid vein

Commoncarotid artery

Right lobe ofthyroid gland


Table 19.2 Hormones of the Thyroid Gland, Parathyroid Glands, and Thymus (Part 1 of 2)


Figure 19.7 The Regulation of Thyroid Secretion

Hypothalamusreleases TRH

Pituitarygland

Anteriorlobe

Anteriorlobe

TRH

TSH

Thyroidgland

Adenohypophysisreleases TSH

Thyroid folliclesrelease T3 and T4

Normal T3 and T4

concentrations,normal bodytemperature

Decreased T3 and T4 concentrations

in blood or lowbody temperature

Increased T3 and T4 concentrationsin blood

HomeostasisDisturbed

HomeostasisRestored

HOMEOSTASIS


The Parathyroid Glands

Located on the back of the thyroid glandTwo types of cells:

Parathyroid cells, or principal cells (Chief Cells)— glandular cells that produce the hormone PTH, which raises the blood calcium

Oxyphil cells and transitional cells— likely immature or inactive principal cells

Regulates calcium homeostasis PTH— parathyroid hormone


Figure 19.8 Anatomy and Histological Organization of the Parathyroid Glands

The location and size of the parathyroidglands on the posterior surface of thethyroid lobes

The histology of the parathyroidand thyroid glands

A histological section showing parathyroid cellsand oxyphil cells of the parathyroid gland

LM 600Parathyroid gland

Oxyphilcells

Parathyroid(chief) cells

LM 100Parathyroid and thyroid gland

Connectivetissue capsuleof parathyroid

gland

Thyroidfollicles

Blood vessel

Left lobe ofthyroid gland

Parathyroidglands


Table 19.2 Hormones of the Thyroid Gland, Parathyroid Glands, and Thymus (Part 1 of 2)


The Thymus Gland

Located on top of the heart Secretes many chemicals that help T

cells of the immune system develop Thymosins

Atrophies as one ages







Thymosins

Testis



Suprarenal Glands


Thyroid Gland

Pituitary Gland







Kidney

Adipose Tissue

Digestive Tract

Pancreatic Islets

Gonads

LeptinResistin


Insulin, glucagon



The Suprarenal Glands

Located on top of kidneys Manages stress levels Can be divided into two regions:

Suprarenal cortex. Yellow in color due to presence of steroid lipids. The Zona Glomerulosa produces

mineralocorticoids. The Zona Fasciculata produces glucocorticoids. The Zona Reticularis produces androgens.

Suprarenal medulla Chromaffin cells produce epinephrine (adrenaline)

and norephinephrine (noradrenaline).


Figure 19. 9ab Anatomy and Histological Organization of the Suprarenal Gland

A suprarenal glandcut to show both the cortex and themedulla. Note theorientation of thesection for part (c).

Medulla

Cortex

Sectional planefor part (b)Left suprarenal(adrenal) gland

Left middlesuprarenal arteryLeft inferiorsuprarenal arteries

Left suprarenal vein

Superior mesentericartery

Left renal vein

Left renal artery

Right and left inferiorphrenic arteries

Inferiorvena cava

Abdominalaorta

Anterior view of the kidney and suprarenalgland. Note the sectional plane for part (b).

Right superiorsuprarenal arteries

Celiac trunk

Right suprarenal(adrenal) gland

Right middlesuprarenal artery

Right inferiorsuprarenal artery

Right renalartery

Right renalvein


Figure 19. 9bc Anatomy and Histological Organization of the Suprarenal Gland

A suprarenal glandcut to show both the cortex and themedulla. Note theorientation of thesection for part (c).

Medulla

Cortex

Histology of the suprarenal gland showingidentification of the major regions

Capsule

Zonaglomerulosa

Zonafasciculata

Zonareticularis

Cortex

Medulla

Suprarenal gland LM 140


Table19.3 The Suprarenal Hormones


Endocrine Functions of the Kidneys and Heart

The kidneys Renin, an enzyme that regulates the blood pressure

and blood volume. Erythropoietin, a peptide hormone that stimulates the

RBC production in red bone marrow. Calcitriol, a steroid hormone

The heart Atrial natriuretic peptide (ANP) Brain natriuretic peptide (BNP)

Both produce hormones involved with the regulation of blood pressure and blood volume


The Pancreas and Other Endocrine Tissues

The Pancreas — located under stomach Alpha cells — glucagon Beta cells — insulin Delta cells — somatostatin (growth-hormone

inhibiting hormone) F cells — pancreatic polypeptide (PP)

Other digestive hormones discussed in digestive chapter







Thymosins

Testis



Suprarenal Glands


Thyroid Gland

Pituitary Gland







Kidney

Adipose Tissue

Digestive Tract

Pancreatic Islets

Gonads

LeptinResistin


Insulin, glucagon



Figure 19.10a Anatomy and Histological Organization of the Pancreas

The gross anatomy of the pancreas

Pancreaticduct

Body ofpancreas

Lobule Tail

Accessorypancreatic

duct

Head ofpancreas

Smallintestine

(duodenum)

Commonbile duct


Table 19.4 Hormones of the Pancreas


Endocrine Tissues of the Reproductive System

Testes Interstitial cells produce androgens (testosterone)

Promotes production of functional sperms, maintains secretory glands, influences secondary sexual characteristics, and stimultes muscle growth

Nurse cells (or sustentabular cells) secrete inhibin

Ovaries Follicular cells produce estrogens and secrete inhibin Corpus luteum releases progestins and relaxin


Table 19.6 Hormones of the Reproductive System


The Pineal Gland

Part of the epithalamus Contains neurons, glial cells, and special

secretary cells called pinealocytes Pinealocytes synthesizes the hormone,

melatonin Melatonin

Slows the maturation of sperm, oocytes, and reproductive organs

Production rate rises at night and declines during the day


Hormones and Aging

Exhibits relatively few changes with advancing ageOne can expect

The changes in reproduction hormone levels at puberty

The decline in the concentration of reproductive hormones at menopause in women

dr. b ch 19_lecture_presentation

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oxytocin tothe pituitary

bloodstream hormones

endocrine systemkey

hormoneantidiuretic

releasing hormones rh

main endocrine organs

lh luteinizing hormone