semest 1 chap 13a

8/13/2019 Semest 1 Chap 13a

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By the end of the lesson, the studentsshould be able to- describe the endocrine system (glands)inthe human body- describe types of hormones- describe the characteristics of hormone

- describe the mechanism of hormoneaction

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213.1 Human HormonesEndocrine System

Consists of ductless glandscalled endocrine glands

which release hormones

directly into thebloodstream to betransported to the target

organs, cells or tissuesrich supply of blood


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13.1 Human HormonesEndocrine System


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413.1 Human HormonesHormones

Organic compound secreted by cells inone part of the bodyand transported via the bloodstream

to the target organs on the other partsof the body

where they induce a change in the

body i.e. to regulate metabolic processes,growth and reproductive


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513.1 Human HormonesHormones


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613.1 Human HormonesTypes of Hormones

Based on chemical compound thereare three types:

1. Proteinsi. Proteinsii. Peptidesiii. Glycoproteins

2. Amines3. Steroids


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1. Proteins proteinse.g. GH, PRL, insulin, glucagon

short polypeptide chains peptidese.g. oxytocin, ADH, calcitonin, PTH

some linked to small carbohydratemolecules glycoproteinse.g. FSH, LH, TSH


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1. Proteinscannot pass through cell membranesrelatively larger molecules

bind to specific receptors on the cellsurface


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2. Aminesderived from protein and amino acidmetabolism

thyroxine, melatonin, epinephrine,norepinephrine


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3. Steroidscommon molecular structure consistsof four rings of carbon atom

lipid solublecan pass through cell membranes

e.g. sex hormones, glucocorticoids,

mineralocorticoids


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1113.1 Human HormonesProperties of Hormones

1. Soluble :- small organic molecules- easy to enter the bloodstream


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2. Specific :- a type of hormone induces a changeon a particular target organs- i.e. fits into a precise target molecule


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3. Small amount :- hormones can cause desired effects(sometimes substantial effects) in lowconcentration - higher concentration can lead toinhibition of their action (negativefeedback)- deficient or excessive amount cangive bad effects in growth anddeveloment


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4. Slow effects :- hormones do not cause immediateeffects (i.e. slow), but- the effects can be permanent


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5. Travels in blood :- hormones are secreted directly intothe blood stream to be transported tothe target organs- i.e. not via specific ducts


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6. Can be denatured :- by temperature, why?


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1713.1 Human HormonesEndocrine Glands

What you should know

The Gland i.e. the major glands only

The Hormone(s) Secreted The Roles/Functions

The Effects of Deficiency

The Effects of Excessive Secretion

the name ofdisease/symptomonly


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1813.1 Human HormonesEndocrine Glands

Major Endocrine Glandshypothalamus and pituitary glandsthyroid and parathyroid glands

pancreasadrenal glandsgonads


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1913.1 Human HormonesHypothalamus

integrates nervous and endocrinefunctionsits neurosecretory cells producehormonesand secrete them to the posterior

pituitary to be releasede.g. oxytocin,

ADH,hormone releasing factors(e.g. GnRH, TRH, CRH)


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213.1 Human HormonesHypothalamus


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2113.1 Human HormonesHypothalamic Hormones: GnRH, TRH

GnRH (gonadotropin - releasinghormone) brings about secretionof FSH and LH, which are classifiedas gonadotropins.

TRH (thyrotropin-releasinghormone) stimulates the secretion of

TSH


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2213.1 Human HormonesPituitary Glands @ Hypophysis

master glands controls hormone secretion of manyother endocrine glandsi.e. other endocrine glands are itstarget organsconsists of two lobes

anterior posterior


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2313.1 Human HormonesPituitary Glands


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2413.1 Human HormonesPosterior Pituitary: ADH

Effects of deficiencyDiabetes insipidus

ADH undersecreted

excessive large amount of waterexcreted in the urine ( polyuria )increased thirst ( polydipsia )some cases: bed-wetting


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2513.1 Human HormonesPosterior Pituitary @ Neurohypophysis

the hormones are neurosecretions fromhypothalamic nerve cellsreleases the hormones to the targetorganse.g. ADH, oxytocin


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antidiuretic hormones @ vasopressina peptide (9 amino acids)target organ:

kidneys representative role:helps regulate body fluid balance

promotes water retention by kidneys

regulated by: water/salt balance


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Effects of excessive secretionedema

water accumulated in the tissuespacesgeneral puffiness


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2813.1 Human HormonesPosterior Pituitary: Oxytocin

Gr. sharp childbirtha peptide (9 amino acids)target organs:

uterus, mammary gland representative role:- stimulate uterine contraction- stimulate milk ejection after childbirthregulated by:nervous system


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2913.1 Human HormonesPosterior Pituitary: Oxytocin

Effects of excessive secretion

miscarriage


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313.1 Human Hormones Anterior Pituitary @ Adenohypophysis

adeno - = glandular i.e. contains many glandular epithelialarger than posterior lobe (75% total

weight)


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3113.1 Human Hormones Anterior Pituitary: Hormones


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3313.1 Human Hormones Anterior Pituitary: FSH

follicle stimulating hormones a glycoproteintarget organs:

ovaries, testes representative role:stimulate growth of follicles andseminiferus tubules

stimulate production of ova and spermsregulated by:GnRH


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3413.1 Human Hormones Anterior Pituitary: FSH

Effects of deficiencyhypogonadism

reduced or absent of secretion ofhormones from sex glandssexual characteristics is not well-developed


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3613.1 Human Hormones Anterior Pituitary: LH

luteinising hormones named after the corpus luteum , atemporary endocrine tissue in the ovaries

a glycoproteintarget organs:- ovaries- testes (@ ICSH: interstitial cell-

stimulating hormone)

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representative roles:stimulate ovulation (i.e. the monthlyrelease of a mature egg from an ovary) andstimulate secretion of estrogen and

progesterone by corpus luteum stimulate secretion of testosterone*

regulated by:GnRH

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Effects of deficiencyhypogonadism

Effects of excessive secretionhypergonadism

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3913.1 Human Hormones Anterior Pituitary: ACTH

adreno cortico tropic hormones a peptidetarget organs:

- cortex of adrenal gland (outer part) representative roles:stimulate adrenal cortex to secreteglucocorticoid

regulated by:CRH, glucocorticoid in blood

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413.1 Human Hormones Anterior Pituitary: ACTH

Effects of deficiency Addison s disease

Effects of excessive secretionexcessive adrenal hormones

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4113.1 Human Hormones Anterior Pituitary: TSH

thyroid stimulating hormones a glycoproteintarget organs:

- thyroid glandrepresentative roles:stimulate secretion of thyroid hormonese.g. thyroxine (T 4), triiodothyronine (T 3)

regulated by: TRH, thyroxine in blood

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Effects of deficiencyhypothyroidism

goiter enlarged thyroid gland

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Effects of excessive secretionhyperthyroidismGraves disease

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4413.1 Human Hormones Anterior Pituitary: MSH*

melanocyte stimulating hormones target organs:- skin

representative roles:fat metabolismstimulate skin darkening

regulated by:MRH, MIH

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4513.1 Human Hormones Anterior Pituitary: GH

growth hormones @ somatotropin a proteintargets:

- most cells, bonesrepresentative roles:

stimulate growth (especially bones) andmetabolic functions

regulated by:hypothalamic hormones

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Effects of deficiency pituitary dwarfs do not grow any tallerthan a normal 6-year-oldchildnormal intelligence andbody proportionsbecome prematurelysenilemost die before 50

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Effects of excessivesecretiongiantism/gigantism

over secretionduring skeletaldevelopmentgrow more than2.5 m and 180 kgdeath occursbefore 30

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Effects of excessive secretionacromegaly over secretion after skeletal systemis fully developeddoes not lengthen bones butthickens them, esp. jaws, hands,feet and eyebrow ridgesosteoporosis, joints painincreased blood pressure

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4913.1 Human Hormones Anterior Pituitary: Prolactin, PRL

lactogenic hormonestargets:- mammary glands

representative roles:stimulates production and secretionregulated by:hypothalamic hormones

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513.1 Human Hormones Anterior Pituitary: Prolactin, PRL

Effects of deficiencylack of milk secretion

Effects of excessive secretionexcessive milk production

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5113.1 Human Hormones Thyroid Gland

located in the neck, anterior to thetracheahas a well developed circulatory systemits follicular cells secrete thyroxine andtriiodothyronine its parafollicular @ C cells secretecalcitonin

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5213.1 Human Hormones Thyroid Gland: Thyroid Hor mones

Thyroxinean amine containing four atoms ofiodine hence, T 4 tetra iodothyronine90% of thyroid secretion

Triiodothyroninean amine containing three atoms ofiodine hence, T

4 tri iodothyronine

highly concentratedseveral times more potent

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common roles:stimulate and maintain metabolic

processescooperate with GH to regulate overallgrowth and maturation, including thedevelopment of the nervous system

regulated by: TSH

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Effects of deficiency goitersevere hypothyroidism

cretinism in children myxedema in adults

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Effects of excessive secretionhyperthyroidismGraves disease

exophthalmos bulging eyesdue toincreased fluid

behind eyes



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5713.1 Human Hormones Thyroid Gland: Calcitonin

a peptidetarget cells

bone breaker cells - osteoclasts

representative roles:lowers calcium and phosphate level inblood

regulated by:

calcium in blood



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5813.1 Human HormonesParathyroid Glands

tiny glands embedded in the posterior of the thyroidsecrete parathormone , PTHa peptide

target cellsosteoclasts (stimulated)

representative roles:

raises calcium and phosphate level inbloodregulated by:calcium in blood

5913.1 Human Hormones


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5913.1 Human HormonesParathyroid Gland: PTH

Effects of deficiencyhypoparathyroidism

hypocalcemiaCa , Palter impulse transmissionosteoporosisimpaired bone growth

muscle tetany (paralysis)



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613.1 Human HormonesParathyroid Gland: PTH

Effects of excessive secretionhyperparathyroidism

hypercalcemia

Ca , Posteoporosis weight losskidney and heart failure



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6113.1 Human HormonesRegulation of Blood Calcium Level



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6213.1 Human HormonesPancreas

Gr. all flesh posterior to stomach

head tucked into the curve ofduodenum



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6313.1 Human HormonesPancreas

functions asexocrine gland(with ducts) indigestive system

endocrine gland(without ducts) which secreteshormones fromclusters of cells,islets ofLangerhans



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Pancreas : Glucagon

a proteinfrom alpha cells of pancreatic isletstarget organs

liver

representative roles:raises blood glucose leveli.e. by glycogenolysis, gluconeogenesis

regulated by:glucose in blood


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Pancreas : Insulin

a proteinfrom beta cells of pancreatic isletstarget organs

liver

representative roles:lowers blood glucose level

regulated by:glucose in blood



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Pancreas : Insulin

Effects of deficiency Diabetes mellitus

Effects of excessive secretionhypoglycemiacan lead to comatose as brain isdeprived of sufficient glucose



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Pancr eas : Glucagon and Insulin



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Adrenal Glands

ad renal (Gr. upon the kidneys ) triangular shaped organsmade up of two separate glands

cortex outer portionmedulla

inner portion



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Adrenal Cortex

produces and secretes:- glucocorticoids- mineralocorticoids

- gonadocorticoids* (small amount)



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Adrenal Cortex: Glucocorticoids

steroids:cortisol , corticosterone, cortisone

target cells:

most cells, esp. liver cells representative roles:

raise blood glucose level - gluconeogenesisregulated by:

ACTH



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Adrenal Cortex: Glucocorticoids

Effects of deficiency Addison s disease

Effects of excessive secretionCushing s disease redistribution of fats to the face,chest, abdomen

tendency toward diabetes mellitusloss of protein muscles weaken


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Adrenal Cor tex : Gonadocorticoids

adrenal sex hormonessteroids: androgens - , estrogens - target organ:

most cellsrepresentative roles:stimulate secondary sex characteristics

regulated by: ACTH



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Adrenal Cor tex : Gonadocorticoids

Effects of deficiency childish character

Effects of excessive secretionadrenogenital syndrome

excessive androgenaccelerate sex development in male

childrenmale characteristics appear in female



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Adrenal Medulla

produces and secretes:- epinephrine/adrenaline- norepinephrine/noradrenaline



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Adrenal Medulla: Epinephrine

steroidstarget organ:

liver, muscle, adipose tissue

representative roles: produces body to react quickly andstrongly to emergenciesregulate carbohydrate and fat metabolism

regulated by:nervous system



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Adrenal Medulla: Norepinephrine

steroidstarget organ:

smooth muscle of blood vessels

representative roles: promotes constriction of blood vesselregulated by:nervous system



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Gonads: Testes

androgens (steroids)testosterone (mostly), inhibintarget organ:

generalrepresentative roles:regulates male secondary sexcharacteristics

spermatogenesis (with LS and FSH)regulated by:FSH and LH



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Gonads: Ovaries steroidsthree types:

estrogensestrin, estrone, estradiol

progesterone @ progestin

relaxin



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Gonads: Ovaries target organ:

various: uterus, mammary glands, general*representative roles:

help regulate menstrual cycle and developmammary glands (e & p)stimulates growth of uterine lining (e & p)stimulates development of female secondarysex characteristics (e)aids in formation of placenta (p)eases childbirth (r)

regulated by:FSH and LH


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Mechanisms of Action Two mechanisms

Gene Activation:Steroid based hormones

Cyclic AMP Activation:Protein, peptide and amine basedhormones

213.1 Mechanisms of Action


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Gene Activation

1. a steroid hormonemolecule passes throughthe cell membrane

2. and binds to a receptor protein in the cytoplasm(or in the nucleus )hormone-receptor complex



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Gene Activation 3. the complex enters the

nucleus and the hormoneexerts an effect upon thechromosome stimulatingtranscription

4. the mRNA enters thecytoplasm and translated into new proteins, e.g.enzyme



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Gene Activation


A i i f AMP @ 2 nd M


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Activation of cAMP @ 2 nd Messenger 1. at the target cell, a peptide hormone molecule

cannot pass through the membrane, why?2. instead, it binds to a receptor present on the

cell surface hormone-receptor

complex


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A i i f AMP


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Activation of cAMP 5. cAMP activates a

series of reactionse.g. it activates protein kinase A inthe conversion of

glycogenglucose


A i i f AMP


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Activation of cAMP


M h i f A ti


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Mechanisms of Action


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1 Appendix

Addi di


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Addison s diseaseSymptoms

muscle weaknessloss of appetitenausea, vomiting, diarrhea

anemia and low blood pressure whenstanding dizziness, faintinghyperpigmentation of skin (bronzed,dark tanning)depressioncraving for salty food

2 Appendix

Addi di


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Addison s disease

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4 Appendix

A g l


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Acromegaly

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5 Appendix

Cretinism


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CretinismSymptoms

mental and skeletalretardationjaundiced and dry

skin puffy eyelidsshoulders sagabdomen protrudesslowness ofmovement andspeech

back

6 Appendix

Myxedema


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MyxedemaSymptoms

swollen facialfeaturesdry swelling skin

slowed speech andmental awarenessintolerance to cold,fatigue and

weakness

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7 Appendix

Islets of Langerhans in Pancreas


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Islets of Langerhans in Pancreas

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8 Appendix

Further references


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Further references

http://www.udel.edu/Biology/Wags/histopage/colorpage/cen/cenacm1.GIF

http://omega.dawsonscollege.qc.ca/ray/endocrine/
http://www.udel.edu/Biology/Wags/histopage/colorpage/cen/cenacm1.GIFhttp://www.udel.edu/Biology/Wags/histopage/colorpage/cen/cenacm1.GIFhttp://omega.dawsonscollege.qc.ca/ray/endocrine/http://omega.dawsonscollege.qc.ca/ray/endocrine/http://omega.dawsonscollege.qc.ca/ray/endocrine/http://omega.dawsonscollege.qc.ca/ray/endocrine/http://www.udel.edu/Biology/Wags/histopage/colorpage/cen/cenacm1.GIFhttp://www.udel.edu/Biology/Wags/histopage/colorpage/cen/cenacm1.GIF

semest 1 chap 13a

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