Histo Review Endocrine

8/14/2019 Histo Review Endocrine

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ENDOCRINE SYSTEM

REVIEW


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Ei guys sorry gumawa nlng akongreview kasi mejo pressed for time Itried to make it as self-study-able as

possible and merong mga questionsin between (yung answer nasa nextslide) if you have questions text menlng or ask on tues morning (or askBea). Pero it would be best if youreferred to a book. Hope this helpsanyway and I hope hope we get

higher grades this time


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Pituitary (neurohypophysis, adenohypophysis) Pars distalis, pars intermedialis; pars nervosa

Chromophobes, acidophils, basophils; Herring body,pituicytes

Rathkes pouch, infundibulum

Adrenal Gland Cortex, medulla

Zona glomerulosa, zona fasciculata, zona reticularis

Thyroid Gland

Thyroid follicles, C cells (parafollicular cells), colloid Parathyroid Gland

Adipose, oxyphil cell, chief cell

Endocrine Pancreas Islets of Langerhans, Beta cell (insulin), Alpha

cell(glucagon) Pineal Gland


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Hypophysis pituitary gland

Located in the diencephalon Comprised of adenohypophysis

(anterior pituitary) and

neurohypophysis Infundibulum: connects pituitary to

hypothalamus


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Pituitary

Adenohypophysis comprised of pars distalisand pars intermedia Pars distalis: secretes growth hormone (GH),

thyroid stimulating hormone (TSH),adenocorticotropic hormone (ACTH), follicle-stimulating hormone (FSH), Luteinizinghormone (LH) and prolactin

Pars intermedia: secretes melanocytestimulating hormone (MSH)

Pars tuberalis: thin extension in contact with

infundibulum Neurohypophysis comprised of pars nervosa,

infundibular stalk and median eminence Pars nervosa (posterior pituitary) : stores ADH

and oxytocin

ADH and oxytocin not synthesized in parsnervosa; secreted by hypothalamus


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Hypophysis pituitary gland

Adenohypophysis (ant.Pituitary)

Pars distalis darker staining

Pars intermedia

in between parsdistalis andpars nervosa

Narrow band ofdarker stainingcells alongright handmargin of slit

Slit remnant of Rathkespouch

Neurohypophysis (post.

Pituitary) Pars nervosa


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Parsnervosa

Pars

intermedia

Parsdistalis


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a rsdistalisa r si n t e r m e dia

a r sn e r v o s a


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Adenohypophysis parsdistalis

Pars distalis Secretory Cells of

pars distalis Chromophils (A):

darker staining,dark cytoplasm Basophils: v. dark

stainingnucleus (darkstaining

cytoplasm) Acidophils: dark

stainingcytoplasm

Chromophobes(B):

hardly stain (onlyfound in anterior

ecretor y cells are arr anged i nlumps s ep arate d by a f ine(eticula r fiber CT thi n blackines w here t he ca i ll aries lie


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Chromophobes


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Chromophils and theirsecretions

chromophilsA cid o p h ils S o m a to tro p h ic

( )ce ll G H

M a m m o tro p h ic( )ce ll Pro la ctin

:pnemonics" (GPA g rowth hormone andp rolactin are secreted by

the a )cidophilsBasophils

Gonadotrophic( , )cell FSH LH

Thyrotropic cell( )TSH

Cotricotrophiccell

( )ACTH- "B FLAT b asophils secrete F ,SH


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Pars distalis


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acidophil b a so p h il

chromophobe


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Question: In this picture of the pars distalis,what type of secretory epithelial cell are

denoted by arrow?


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Red: Basophil(other cells are acidophils yellow;

chromophobes orange)


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Question: In this picture of the pars distalis,what type of secretory epithelial cell is

labeled 'a'?


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Chromophobe (no stain) -other chromophobesyellow arrow

(other cells are b- basophil; c- acidophil)


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Question: What hormones do these cellssecrete?


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Prolactin and Growth hormone (mammotropic &somatotropic)

(other cells: blue chromophobe, yellow:basophil)


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Capillary

NOTE:endocrineglands are

highlyvascularized (sincesecretions

go to blood) Encircled:

nucleus ofendothelial

cell


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Question: Identify (ID) cell. IDgland


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Chromophobepars distalis hypothalamus

other structures (basophil purple stain and acidophil pink stain)encircled blood vessel with RBC


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a r sn e r v o s a


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Pars intermedia

May be cystic Parsintermediafused

with/withinpars distalis(purple arrow)

Lumen of

rathkes pouchdisappear Split in right

(green)

fixationartifact


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Question: Identify glandIdentify space at tip of arrow


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Pituitary glandcystic pars intermedia

other structures (notice lighter pars nervosa with pituicytes; parsdistalis with dark staining basophils and acidophils and light staining

chromophobes)

arsnervosaarsdistalis


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a r sn e r v o s a


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Posterior pituitary functions

Stores and releases 2 hormones thatare produced in the hypothalamus:

Antidiuretic hormone(ADH/vasopressin):

Promotes the retention of H2

0 by the

kidneys.

Less H20 is excreted in the

urine.

Oxytocin:

Stimulates contractions of the uterusduring parturition.

Stimulates contractions of themammary gland alveoli.

Milk-ejection reflex.


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Neurohypophysis parsnervosa

Cells of pars nervosa Pituicytes

(C):neuroglial-like;

Herring bodies:

cellular projectionswhich storeneurotransmitters

accumulation ofsecretion within theaxon of neuronswhose cell bodies liein the hypothalamusof the brain

no nuclei

Nuclei of endothelial


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Pars nervosa

pituicytes


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Question : ID gland. IDstructures


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ID gland. ID structuresPost. Pituitary pars nervosaHerring bodypituicyte nucleusNucleus of endothelial cell of fenestrated capillary


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Question : ID gland. IDpointed structure


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Post. Pituitary; Herring body


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Question: ID gland. ID pointedstructure


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Pituicyte (round/oval nuclei)


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Thyroid Gland

Largest of the pure endocrine glands

Composed of many spherical hollow sacs(thyroid follicles) surrounded by cells(follicular cells/principal cells)

Follicles are filled with a colloid Follicular cells use the thyroglobulin and

iodide stored in the colloid to produceprimary thyroid hormones (ex. T3 and T4)

In between follicles are parafollicular cellswhich secrete calcitonin

Only gland which stores its hormonalsecretion extracellularly before releasinginto bloodstream


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Thyroid Gland


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Thyroid follicles


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Functions of T3

Stimulates protein synthesis.

Promotes maturation of nervous system.

Stimulates rate of cellular respiration by:

Production of uncoupling proteins. Increase active transport by Na+/K+ pumps.

Lower cellular [ATP].

Increases metabolic heat.

Increases metabolic rate. Stimulates increased consumption of

glucose, fatty acids and other molecules.


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Thyroid Gland

Thyroid follicleFollicular/ principal

cells: simple cuboidalcells (activelysynthesizing), simple

squamous cells(inactive stage)

-line the follicle -lesser

cytoplasm compared

to parafollicular cellsColloid : pink, contains

thyroglobulin andiodine (hormoneprecursors)


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Parafollicular cells

Parafollicularcells

-C cells -cells

outside offollicle

-producecalcitonin


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Q ti Wh t i thi


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Question: What is thishomogenous substance?

Colloid filled with thyroglobulin glycoprotein precursor of thyroid


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Colloid filled with thyroglobulin glycoprotein precursor of thyroidhormone

other structures (follicle cells -green, parafollicular -purple(calcitonin), black capillary)


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Parathyroid Gland


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Parathyroid Glands

Parathyroid (A)embedded inthyroid (B)

Notice thyroid

follicles filled withcolloid (lower half)

Notice the absenceof follicles in

parathyroid tissue(upper half)

Parathyroid cellsusually darkerstaining (due to


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Some functionsof PTH:

Single mostimportant

hormone in thecontrol of blood[Ca2+ ].

inc renal tubularabsorption ofCa

inc intestinal Ca

absorp


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Notice thattheparathyroid glandcontains

bloodvesselsandadipocytes

Notice that

Chief cellsappear asbands/ribbons orcords

(yellowscribble in


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Question: ID gland and cell


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(xy phil cells b igger)ytoplasm

Adipocytes

hi ef c ells


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Adrenal Gland

Encapsulated

Comprised of a cortex and medulla

Cortex originates from mesoderm and

medulla from the neural crest Cortex further subdivided into zona

glomerulosa, zona fasciculata andzona reticularis

Cortex does not receive neuralstimulation (must be hormonallystimulated via ACTH)

General parts of Adrenal


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General parts of AdrenalGland

Capsule (A):

Cortex (B): dividedinto three zones

withinareolar/reticularCT framework

Medulla (C):


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Adrenal Gland

Adrenal Gland: Cortical


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Adrenal Gland: CorticalDivision


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d re n a l m e d u lla


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Z o n u la g lo m e ru lo sa


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Zona glomerulosa Beneath capsule

Cells are composedof columnar cellsarranged insmall clusters

Cells have heavilystained nucleiand basophiliccytoplasm

Fairly dark and

quite narrow involved in

electrolyteregulation viasecretion of

aldosterone and

Z. Glomerulosa arranged in


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gclusters (red)

encircled in yellow: ang walang kamatayang endothelial cellnucleus

Question: ID gland. Id


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glayer

W h a t d o e s itsecrete?


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Adrenal glandzona glomerulosa

secretes mineralcorticoids

(aldosterone)


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Zona Fasciculata Zona fasciculata

Center ofadrenal cortex

Widest, palestlayer

Identified by

arrangementof vacuolatedcells inverticalcolumns orstrips

Cells appear paleand foamylookingbecause ofdissolved lipidof their

secretions

Zona fasciculata


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Zona fasciculataencircled in yellow: endothelial cells of

capillary

Notecolumnar

arrangement ofcells(vertical,

parallelto eachotherwith

capillarie


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Zona Reticularis

Innermostcortical layer

cells are

somewhatunorganized(anastomosingcords)

involved in sexhormones (sexsteroids)

Question: ID


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Question: IDgland. ID layers


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Adrenal gland

Zona reticularisand medullary

layer

d l d ll


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Adrenal Medulla

Lighter thancortex

Site of

epinephrine andnorepinephrine

production Cells:

ganglioncells (in

blue arrow)

Chromaffin cell (secrete


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Chromaffin cell (secretecatecholamines)

Functions of adrenal


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Functions of adrenalmedulla

Innervated by preganglionicsympathetic axons (SNS)

Increase respiratory rate.

Increase HR and cardiac output. Vasoconstrict blood vessels, thus

increasing venous return.

Stimulate glycogenolysis. Stimulate lipolysis.

Question: Why does the venous bloodd i i th t t th d ll h


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draining the cortex to the medulla have a

high concentration of glucocorticoids?


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Glucocorticoids are needed for the synthesis ofphenyl ethanolamine N methylene a keyenzyme in the synthesis of nor epinephrine

P


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Pancreas

Accessory gland for digestion

Endocrine function: insulin andglucagon


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Islets of Langerhans (A):endocrine portion ofpancreas Lighter staining

compared to exocrineacinar ducts (producecells for the digestivesystem)

Appear in patches

throughout pancreas types of cells

alpha cells secreteglucagon (outer)

beta cells secrete

insulin (inner)


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types of cells alpha

cellssecreteglucagon

( usually stainredandfoundinperiph

eryouter)

beta cellssecreteinsulin(usuallystain

blue


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Pi l Gl d


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Pineal Gland

Projection of the roof ofthe diencephalon with asmall recess of the thirdventricle extending to its

stalk Covered by pia mater

Hormone produced ismelatonin

Hormone production :greatest in the dark

Comprised of Pinealocytes & glial cells

Pineal sand : increases

Pi l Gl d


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Pineal Gland

Pinealocyte (region oforange arrow)

Major cell type

Nuclei round with

prominent nucleoli

Secrete melatonin

Glial /interstitial cell

Nuclei stain moredeeply

Brain sand

Aggregations of Ca+

B i d


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Brain sand


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Histo Review Endocrine