ENDOCRINOLOGYThe scientific study of the endocrine

glands and their hormones

THINGS NEED TO KNOW

• General Features of the Endocrine System and Important definitions

• Evolution of the Endocrine System

• Classes of Hormones

• Actions of Hormones

General Features of the Endocrine System

1. Endocrine glands are ductless

2. Endocrine glands have a rich supply of blood.

3. Hormones, produced by the endocrine glands are secreted into the bloodstream.

4. Hormones travel in the blood to target cells close by or far away from point of secretion.

5. Hormones receptors are specific binding sites on the target cell.

Important Definitions

• What are hormones?Hormones are organic chemical messengers produced and

secreted by endocrine cells into the bloodstream. Hormones regulate, integrate and control a wide range of physiologic functions.

Important Definitions Cont.

• What are endocrine glands?Endocrine glands are ductless glands comprised

of endocrine cells. This means that these glands do not have ducts that lead to the outside of the body. For example, sweat glands are NOT endocrine glands (they are instead exocrine glands) because sweat glands have ducts that lead to the outside surface of your skin (that’s how the sweat gets out). The fact that endocrine glands are ductless means that these glands secrete hormones directly into the blood stream (instead of to the outside of your body).

Important Definitions Cont.• What are target cells?Target cells refer to cells that contain specific receptors

(binding sites) for a particular hormone. Once a hormone binds to receptors on a target cell, a series of cellular events unfold that eventually impact gene expression and protein synthesis.

Important Definitions Cont.

• What are hormone receptors?Hormone receptors are binding sites on the target cell

(either on the surface or in the cytoplasm or nucleus of the target cell) that are activated only when specific hormones bind to them. If a hormone does not/cannot bind to it’s receptor, then no physiologic effect results.

See next slide for a picture of a hormone bound to its receptor

Growth hormone regulates cell growth by binding to growth hormone receptors on target cells.

THINGS NEED TO KNOW

• General Features of the Endocrine System and Important definitions

• Evolution of the Endocrine System

• Classes of Hormones

• Actions of Hormones

Evolution of the Endocrine System

• It is likely that the vertebrate endocrine system evolved from bacterial signaling systems that allowed bacteria to both perceive extra- and intracellular signals.

• Primitive endocrine signaling likely arose from cells releasing chemical signals to communicate with neighboring cells (paracrine signaling).

Classes of Hormones

• Steroids vs. Peptide Hormones

Hormones fall into 2 general classes based on their molecular structure and synthesis.

• All steroid hormones are made initially from the precursor (precursor = first step in biosynthetic pathway) cholesterol.

See next slide for a diagram of the biosynthetic pathway of steroid hormonesfrom cholesterol.

Steroid Hormones

• Steroid hormones are produced by the gonads and adrenal cortex.

• Thyroid hormones are not steroids, but will be categorized with steroids for simplicity.

• Steroid hormones are made from cholesterol in the smooth endoplasmic reticulum and mitochondria of endocrine cells.

Steroid Hormones

• Steroid hormones cannot be stored in vesicles in the endocrine cells that produce them. As soon as steroid hormones are produced, they diffuse out of the endocrine cell and enter the bloodstream.

• Steroid hormones are lipid soluble and their receptors are located inside their target cell.

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Steroid hormones:Steroid hormones:

Penetrate the cell and bind to a receptor protein Penetrate the cell and bind to a receptor protein inside the targetinside the target cell. This cell. This also will trigger also will trigger signal transduction pathwaysignal transduction pathway (for triggering mRNA (for triggering mRNA transcription for synthesizing a specific protein).transcription for synthesizing a specific protein).

• Estrogen, progesterone, vitamin D and NO.Estrogen, progesterone, vitamin D and NO.– Usually, the intracellular receptor activated by a hormone is a Usually, the intracellular receptor activated by a hormone is a

transcription factor.transcription factor.

Peptide Hormones

• Peptide hormones are comprised of chains on amino acids.

• Like most proteins, peptide hormones are synthesized on ribosomes of the (rough) endoplasmic reticulum of endocrine cells.

• Peptide hormones can be stored in vesicles in endocrine cells until they are needed at some later point.

Peptide Hormones

• Peptide hormones do not readily pass through cell membranes (lipid bilayers) and they are referred to as water soluble.

• Receptors for peptide hormones are found on the cell surface of their target cells.

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Most chemical signals bind to plasma-membrane proteins, Most chemical signals bind to plasma-membrane proteins, initiating signal-transduction pathways.initiating signal-transduction pathways.

Mechanism of chemical signaling:Mechanism of chemical signaling:The chemical signals secreted by a cell either:The chemical signals secreted by a cell either:

Protein hormonesProtein hormones::

Bind to a receptor protein on the surface of the target cell whichBind to a receptor protein on the surface of the target cell which will trigger will trigger signal transduction pathwaysignal transduction pathway..

Actions of Hormones

• Fetal development and differentiation• Cell growth and cancer• Metabolism• Cardiovascular function• Renal function• Skeletal function• Reproductive function• Immune function• Central nervous system function

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• Nervous and endocrine systems are the main internal Nervous and endocrine systems are the main internal communication and regulation systems.communication and regulation systems.

• The animal hormone-secreting cells constitute the endocrine The animal hormone-secreting cells constitute the endocrine system.system.

• Hormone secreting organs are called Hormone secreting organs are called Endocrine GlandsEndocrine Glands (ductless (ductless glandsglands الصماء الصماء الغدد .(.( الغدد

• Hormone is a chemical signal secreted into blood stream and Hormone is a chemical signal secreted into blood stream and regulates communicating messages within the body.regulates communicating messages within the body.

• Target cell is the site that reached by the hormone to which it Target cell is the site that reached by the hormone to which it responds.responds.

• Complete changes in the body is regulated by hormones (e.g. Complete changes in the body is regulated by hormones (e.g. metamorphosis in insects).metamorphosis in insects).

• Types of hormones are [Types of hormones are [Polypeptide H., Amino acid derivatives H Polypeptide H., Amino acid derivatives H or Steroid H.or Steroid H.]. ].

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• Tropic hormones:Tropic hormones: )الهرمونات المحفزة )المنبهة target other endocrine glands and are important to understanding chemical coordination.

• Many endocrine organs contain specialized nerve cells called Many endocrine organs contain specialized nerve cells called neurosecretory cellsneurosecretory cells that secret hormones. that secret hormones.

• The hormone epinephrine has two functions:The hormone epinephrine has two functions:– As a hormone of the endocrine system.As a hormone of the endocrine system.– As a signal in the nervous system. As a signal in the nervous system.

• Feedback is common in regulation the activity of both endocrine Feedback is common in regulation the activity of both endocrine and nervous systems (homeostasis) (and nervous systems (homeostasis) (Fig. 45.1, page 956):):– Calcitonin and parathyroid hormones play an important role in Calcitonin and parathyroid hormones play an important role in

maintaining the concentration of the blood calcium constant.maintaining the concentration of the blood calcium constant.– They are secreted from thyroid and parathyroid glands respictively.They are secreted from thyroid and parathyroid glands respictively.

• Hormones regulate the development of Hormones regulate the development of invertebrates (e.g. insects) invertebrates (e.g. insects)

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Tropic hormonesTropic hormones((الهرمون المنبه للغددالهرمون المنبه للغدد))

TTarget other arget other endocrineendocrineglandsglands and are and areimportant to important to understandingunderstandingchemical coordination.chemical coordination.

• Human has Human has 9 9

endocrine glandsendocrine glands..

The Vertebrate Endocrine SystemThe Vertebrate Endocrine System

Fig. 45.5, Page 960

الصنوبالنخاميرية

ةالدرقية

الكظرية

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• The The hypothalamushypothalamus integrates endocrine and integrates endocrine and nervous function.nervous function.

– Neurosecretory cells of the hypothalamus produce Neurosecretory cells of the hypothalamus produce hormones.hormones.

a)a) Releasing hormones stimulate the anterior pituitary Releasing hormones stimulate the anterior pituitary ((adenohypophysisadenohypophysis) to secrete hormones.) to secrete hormones.

b)b) Inhibiting hormones prevent the anterior pituitary from Inhibiting hormones prevent the anterior pituitary from secreting hormones.secreting hormones.

The hypothalamus and pituitary integrate many The hypothalamus and pituitary integrate many functions of the vertebrate endocrine systemfunctions of the vertebrate endocrine system

1)- Pituitary gland:1)- Pituitary gland: secrets 9 hormonessecrets 9 hormones ( 7 hormones by the the anterior part and 2 hormones by the posterior part).anterior part and 2 hormones by the posterior part).

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A)- Anterior pituitary hormones.A)- Anterior pituitary hormones.1)1) Growth hormone (GH):Growth hormone (GH): a a protein. protein.

• Stimulates growth and metabolism.Stimulates growth and metabolism.• Secretion regulated by hypothalamic hormones.Secretion regulated by hypothalamic hormones.• Acts directly on tissues or acts Acts directly on tissues or acts viavia growth factorsgrowth factors..• Gigantism:Gigantism: العملقةالعملقة excessive GH during excessive GH during developmentdevelopment..

• AcromegalyAcromegaly: excessive GH production during : excessive GH production during adulthoodadulthood..• Hypopituitary dwarfism Hypopituitary dwarfism القزميةالقزمية: childhood GH deficiency.: childhood GH deficiency.

2)2) Prolactin (PRL):Prolactin (PRL): a a proteinprotein..• Stimulates milk production and secretion from Stimulates milk production and secretion from mammary mammary

glandgland الغدد اللبنيةالغدد اللبنية. This secretion regulated by hypothalamic . This secretion regulated by hypothalamic hormones.hormones.

3)3) Gonadotropins (Gonadotropins (Gonotropic Gonotropic محفز للمناسلمحفز للمناسل): ): glyocoproteinsglyocoproteins..

• Follicle-stimulating hormone (FSH).Follicle-stimulating hormone (FSH).– Stimulates production of Stimulates production of spermssperms and and ovaova..– Secretion regulated by hypothalamic hormones.Secretion regulated by hypothalamic hormones.

• Luteinizing hormone (LH) Luteinizing hormone (LH) الم&حفز لتكوين الجسم األصفرالم&حفز لتكوين الجسم األصفر..– Stimulates ovaries and testes. Stimulates ovaries and testes. – Secretion regulated by hypothalamic hormones.Secretion regulated by hypothalamic hormones.

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4)4) Thyroid-stimulating hormone (TSH):Thyroid-stimulating hormone (TSH): a a glycoproteinglycoprotein..• Stimulates thyroid gland.Stimulates thyroid gland.

• Secretion regulated by thyroxine in blood.Secretion regulated by thyroxine in blood.

• Secretion regulated by hypothalamic hormones.Secretion regulated by hypothalamic hormones.

5)5) Adrenocorticotropic hormone (ACTH):Adrenocorticotropic hormone (ACTH): a a peptidepeptide• Stimulates adrenal cortex secretion of glucocorticoidsStimulates adrenal cortex secretion of glucocorticoids

• Secretion regulated by glucocorticoids and hypothalamic Secretion regulated by glucocorticoids and hypothalamic hormones.hormones.

6)6) Melanocyte-stimulating hormone (MSH):Melanocyte-stimulating hormone (MSH): a a peptidepeptide..• May play a role in fat metabolism.May play a role in fat metabolism.

7)7) EndorphinsEndorphins: : peptidespeptides..• Inhibit pain perception.Inhibit pain perception.

• Effects mimicked by heroin and other opiate drugs.Effects mimicked by heroin and other opiate drugs.

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Fig. 45.6b, Page 963

The anterior pituitary gland hormonesThe anterior pituitary gland hormones

Also called gonadotropine Also called gonadotropine hormones hormones المناسل المناسل هرمونات هرمونات

Adrenocorticotropic

Melanocyte-stimulating H.

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B)- Posterior pituitary hormones.B)- Posterior pituitary hormones.– OxytocinOxytocin: a peptide.: a peptide.

• Stimulates contraction of the uterus and Stimulates contraction of the uterus and mammary glandsmammary glands..

• Secretion regulated by the nervous system.Secretion regulated by the nervous system.

– Antidiuretic hormone (ADH):Antidiuretic hormone (ADH): م%ضاد إلدرار البولم%ضاد إلدرار البول a peptide.a peptide.• Promotes retention of water by the Promotes retention of water by the kidneyskidneys (in Kidney tubules). (in Kidney tubules).

• High level decreases urination and High level decreases urination and vicevice versaversa..

• Secretion regulated by water/salt balance.Secretion regulated by water/salt balance.

2- Pineal gland:2- Pineal gland: الغدة الصنوبريةالغدة الصنوبرية is a small mass of tissue near the center of the is a small mass of tissue near the center of the mammalian brain and mammalian brain and involved in involved in biorhythmsbiorhythms..

– The pineal gland secretes the hormone, The pineal gland secretes the hormone, melatoninmelatonin, an , an amineamine..• Involved in biological rhythms associated with reproduction.Involved in biological rhythms associated with reproduction.

• Secretion regulated by light/dark cycles.Secretion regulated by light/dark cycles.

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Posterior pituitaryPosterior pituitary

(neurohypophysis)

stores and secretes

hormones produced

by the hypothalamus.

Antidiuretic HAntidiuretic H

32See Fig. 45.7, Page 965See Fig. 45.7, Page 965

Thyroid Thyroid releasing H. releasing H.

Thyroid Thyroid stimulating H. stimulating H.

• The The thyroid glandthyroid gland of mammals consists of mammals consists of of two lobestwo lobes located on the ventral located on the ventral surface of the trachea. It contains 4 surface of the trachea. It contains 4 small small Parathyroid glandsParathyroid glands. It plays role in . It plays role in maintaining normal blood pressure, maintaining normal blood pressure, heart rate digestion ..etc.heart rate digestion ..etc.

• Thyroid glands secretes 3 Thyroid glands secretes 3 hormones:hormones:

I.I. Tri-iodothyronineTri-iodothyronine [[(T(T33), 3 ), 3 II atomsatoms]: ]: amino acid derivative.amino acid derivative.

II.II. ThyroxineThyroxine [ [(T(T44), 4 ), 4 II atoms atoms]:]: amino acid derivativeamino acid derivative..

– Stimulates and maintain metabolic Stimulates and maintain metabolic processes.processes.

– Secretion regulated by Secretion regulated by TSHTSH hormones. hormones.

3. Thyroid gland: 3. Thyroid gland: secretssecrets hormones function in development,hormones function in development, bioenergetics, and homeostasis bioenergetics, and homeostasis البيئة ثبات

الداخلية چالفسيولو ـية

Fig. 45.8, Page 965

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a)a) Hyperthyroidism:Hyperthyroidism: the the excessiveexcessive secretion of thyroid secretion of thyroid hormones causes:hormones causes:

• high body temperature high body temperature

• sweating sweating

• weight loss weight loss

• IrritabilityIrritability

• high blood pressure.high blood pressure.

b)b) Hypothyroidism:Hypothyroidism: an an insufficientinsufficient قليلقليل amount of thyroid amount of thyroid

hormones hormones because deficiency of because deficiency of II in human diet in human diet (causes (causes Goiter).Goiter).

Infants: cretinism.Infants: cretinism. Adults: weight gain, lethargy, cold intolerance.Adults: weight gain, lethargy, cold intolerance. Goiter Goiter تضخم الغدةتضخم الغدة: often associated with iodine deficiency : often associated with iodine deficiency نقصنقص..

III.III. Calcitonin:Calcitonin: aa peptidepeptide.. Lowers blood Lowers blood CaCa2+ 2+ levels.levels. Its secretion regulated by calcium in blood.Its secretion regulated by calcium in blood.

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• PTH is secreted byPTH is secreted by The four The four parathyroid glandsparathyroid glands which embedded which embedded

in the surface of the thyroid glandin the surface of the thyroid gland. . It functions as:It functions as:– Raises blood Raises blood CaCa2+ 2+ levels.levels.

– Secretion regulated by calcium in the blood.Secretion regulated by calcium in the blood.

– Causes Causes osteoclastsosteoclasts فقد الكالسيومفقد الكالسيوم to break down bone, releasing to break down bone, releasing CaCa2+2+ into the blood.into the blood.

– Stimulates the kidneys to reabsorb Stimulates the kidneys to reabsorb تعيد إمتصاصتعيد إمتصاص CaCa2+2+..

– Stimulates kidneys to convert vitamin D to its active form, which Stimulates kidneys to convert vitamin D to its active form, which stimulate intestine to absorb stimulate intestine to absorb CaCa2+2+..

– PTH and calcitoninPTH and calcitonin are antagonistic are antagonistic متضادينمتضادين hormones. Thushormones. Thus PTH PTH and calcitonin regulate blood calcium level (important role in and calcitonin regulate blood calcium level (important role in homeostasis).homeostasis).

• HypoparathyoidismHypoparathyoidism (tetany):(tetany): it is a it is a lack of PTH which causes: lack of PTH which causes:

– CaCa2+2+ levels in the blood drop.levels in the blood drop.

– Convulsive contractions of the skeletal muscles.Convulsive contractions of the skeletal muscles.

Parathyroid gland: Parathyroid gland: Parathyroid hormoneParathyroid hormone (PTH): (PTH): a peptidea peptide

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Read Read carefully carefully the caption the caption of Figure of Figure 45.9, Page 45.9, Page 967967

Hormonal control of Hormonal control of CaCa2+2+ homeostasis in mammals bloodhomeostasis in mammals blood

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• The pancreas has both endocrine and exocrine functions.The pancreas has both endocrine and exocrine functions.– Exocrine function: secretion of bicarbonate ions and digestive Exocrine function: secretion of bicarbonate ions and digestive

enzymes.enzymes.

– Endocrine function: Endocrine function: insulininsulin and and glucagonglucagon secreted by secreted by betabeta and and alphaalpha cells of cells of islets of Langerhans islets of Langerhans جيوب النجرانزجيوب النجرانز..

1.1. Insulin:Insulin: a protein secreted by a protein secreted by beta cellsbeta cells..• Lowers blood glucose levels.Lowers blood glucose levels.

– Stimulates all body cells (except brain cells) to take up glucose.Stimulates all body cells (except brain cells) to take up glucose.

– Slows glycogenolysis Slows glycogenolysis يبطىء تحلل الجليكوجينيبطىء تحلل الجليكوجين (a source of (a source of glucose).glucose).

– Inhibits gluconeogenesis Inhibits gluconeogenesis يوقف تكوين الجلوكوزيوقف تكوين الجلوكوز..

• Secretion regulated by glucose in blood (Secretion regulated by glucose in blood (negative feedbacknegative feedback).).

– Hypoinsulinism:Hypoinsulinism: diabetes mellitus diabetes mellitus نقص اإلنسوليننقص اإلنسولين..1.1. Hereditary factors Hereditary factors عامل وراثىعامل وراثى and play a role in its development.and play a role in its development.

2.2. High blood sugar levels High blood sugar levels –– sugar excreted in the urine. sugar excreted in the urine.

3.3. Symptoms: excessive urination Symptoms: excessive urination كثرة التبولكثرة التبول and excessive thirst and excessive thirst العطشالعطش..

5.5. PancreasPancreas: : Endocrine tissues of the pancreas secrete insulin andEndocrine tissues of the pancreas secrete insulin and glucagon, antagonistic hormones that regulate blood glucose glucagon, antagonistic hormones that regulate blood glucose

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a)a) Type Type II diabetes mellitusdiabetes mellitus ( (insulin-dependent diabetesinsulin-dependent diabetes).).• Autoimmune disorder.Autoimmune disorder.

• Usually appears in childhood Usually appears in childhood الطفولةالطفولة..• Treatment: insulin injections.Treatment: insulin injections.

b)b) Type Type IIII diabetes mellitusdiabetes mellitus ( (non-insulin-dependent diabetesnon-insulin-dependent diabetes).).• Usually due to Usually due to target cellstarget cells having a decreased having a decreased responsivenessresponsiveness to to

insulin insulin قلة اإلستجابة لإلنسولينقلة اإلستجابة لإلنسولين. .

• Usually occurs after age 40 Usually occurs after age 40 –– risk increases with age. risk increases with age.

• Accounts for over 90% of diabetes cases.Accounts for over 90% of diabetes cases.

2.2. Glucagon:Glucagon: a protein secreted by a protein secreted by alpha cellsalpha cells..

• Raises blood glucose levels. Raises blood glucose levels. a)a) Stimulates glycogenolysis Stimulates glycogenolysis تحلل الجليكوجينتحلل الجليكوجين in the liver and in the liver and

skeletal muscle to produce glucose. skeletal muscle to produce glucose.

b)b) Secretion regulated by glucose in blood (negative feedback).Secretion regulated by glucose in blood (negative feedback).

38Fig. 45.10

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• The adrenal glands are located adjacent to the kidneys.The adrenal glands are located adjacent to the kidneys.– The The adrenal cortexadrenal cortex القشرةالقشرة is the outer portion.is the outer portion.

– The The adrenal medullaadrenal medulla is the inner portion. is the inner portion.

I- Adrenal medullaI- Adrenal medulla المركزالمركز.. – Developmentally and functionally related to the nervous system.Developmentally and functionally related to the nervous system.

– It producesIt produces the following hormones (the following hormones (in response to stressin response to stress):):

a)a) EpinephrineEpinephrine (adrenaline هرمون القلبهرمون القلب).

b)b) NorepinephrineNorepinephrine (noradrenaline).

They are amino acid derivatives (synthesized from tyrosine) They are amino acid derivatives (synthesized from tyrosine) and function as:and function as:

• Raises blood glucose level and blood fatty acid level.Raises blood glucose level and blood fatty acid level.

• Increases heart rate and stroke volume and dilates bronchioles.Increases heart rate and stroke volume and dilates bronchioles.

• Shunts blood away from skin, digestive organs, and kidneys, Shunts blood away from skin, digestive organs, and kidneys, and increases blood flow to heart, brain, and skeletal muscle. and increases blood flow to heart, brain, and skeletal muscle.

6. 6. The adrenal gland:The adrenal gland: adrenal medulla and adrenal cortex helpadrenal medulla and adrenal cortex help the body manage stress the body manage stress

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II- Adrenal cortex:II- Adrenal cortex: reacts to stress. reacts to stress.• Secretion of Secretion of corticosteroidscorticosteroids (a family of steroid hormones) is (a family of steroid hormones) is

regulated by the nervous system in response to stress for example:regulated by the nervous system in response to stress for example:

a)a) Glucocorticoids.Glucocorticoids.• Raises blood glucose level.Raises blood glucose level.• Secretion regulated by ACTH (Secretion regulated by ACTH (Adrenocorticotropic hormoneAdrenocorticotropic hormone).).• Abnormally high doses are administered as medication to Abnormally high doses are administered as medication to

suppress the inflammation response.suppress the inflammation response.

b)b) MineralocorticoidsMineralocorticoids ( (example: example: aldosteronealdosterone, which affects salt and , which affects salt and

water balancewater balance).).• Promotes re-absorption of NaPromotes re-absorption of Na++ and excretion of K and excretion of K++ in kidneys. in kidneys.

• Their secretion regulated by KTheir secretion regulated by K++ in blood. in blood.

– A third group of corticosteriods are A third group of corticosteriods are Sex hormonesSex hormones..• Androgens secreted by the adrenal cortex may account for the female Androgens secreted by the adrenal cortex may account for the female

sex drive.sex drive.• The adrenal cortex also secretes small amounts of The adrenal cortex also secretes small amounts of estrogensestrogens and and

progesteroneprogesterone..

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Fig. 45.14

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a)a) TestesTestes hormones: hormones:– TestosteroneTestosterone): steroids.): steroids.

• Supports sperm formation.Supports sperm formation.

• Promote development and maintenance of male sex characteristics.Promote development and maintenance of male sex characteristics.

• Secretion regulated by FSH and LH.Secretion regulated by FSH and LH.

b)b) OvariesOvaries hormones: hormones:

1)1) EstrogensEstrogens: steroids.: steroids.• Stimulate uterine lining growth.Stimulate uterine lining growth.

• Promote development and maintenance of female sex Promote development and maintenance of female sex characteristics.characteristics.

• Secretion regulated by FSH and LH.Secretion regulated by FSH and LH.

2)2) ProgesteroneProgesterone: steroids.: steroids.• Promotes uterine lining growth.Promotes uterine lining growth.

• Secretion regulated by FSH and LH.Secretion regulated by FSH and LH.

7. 7. Tests and ovaries:Tests and ovaries: Gonadal steroids regulate growth, Gonadal steroids regulate growth, development, reproductive cycles, and sexual behaviordevelopment, reproductive cycles, and sexual behavior

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8- Thymus gland:

Secretes Thymosin: a peptide.It stimulates T lymphocytesIt stimulates T lymphocytes.

Protein hormones affect target cells Protein hormones affect target cells viavia receptors on the membrane protein receptors on the membrane protein

Steroid hormones inter the target cells Steroid hormones inter the target cells and trigger protein synthesis and trigger protein synthesis viavia receptors in the nucleus.receptors in the nucleus.

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Page 961Page 961

45

Table 45.1 (continued)

• Many of the body's most basic functions are regulated by the endocrine system— eight different glands located

www.youtube.com/watch?v=kIPYVV4aThM

PLZ OPEN THE VIDEO

• PLZ OPEN THE VIDEO

www.youtube.com/watch?v=YiK8gHPYe6oGrowth hormone (GH)

• Q1: Write whether each of the following statements is True (T) or False (F) :• 

•1-The adrenal gland is epinephrine source.• 2-Epinephrine and norepinephrine hormones are responsible for the "fight or flight"

response to danger• 3-Luteinizing hormone (LH) stimulates hormone production by the ovaries and testes• 4-Posterior pituitary is endocrine organ that does not actually manufacture hormones

but, rather, stores hormones produced elsewhere. • 5-The hypothalamus produces a releasing hormone that stimulates the pituitary to

secrete GH.

• 6-FSH (follicle-stimulating hormone) and LH (luteinizing hormone) are trophic

hormones that are also known as gonadotropins.

.

• The mammary glands of a pregnant female will begin to produce milk in response to changes in the level of prolactin 

• High levels of T3 and T4 inhibit the secretion of TRH and TSH.

• Pituitary dwarfism disorder is caused by hyposecretion of growth hormone.

• When Ca2+ levels fall, PTH stimulates bone cells to decompose the matrix of bone and stimulates reabsorption of Ca2+ in the renal tubules.

• Every time you eat a cookie or candy bar, your blood sugar

increases. This triggers an increase in the hormone insulin 

• Insulin and glucagon hormones have antagonistic effects• At low blood sugar, pancreatic alpha cells stimulated, glucagon

released, breakdown of glycogen in target cells. • 

•.The adrenal gland is epinephrine source•14-Type 1 diabetes mellitus is an autoimmune disease in which the

immune system attacks beta cells in the pancreas.• 15-The adrenal medulla is stimulated by nerve signals carried from

the brain.

• •Q2: Choose the correct answer (one answer only) :

• 1- oxytocin regulated by;

• a) nervous system

• b) hypothalamic hormones

• c) ACTH

• d)Glucocorticoids

•  

• 2-estrogens is;

• a) steroid hormone

• b)protein hormone

• c)glycoprotein

• d) amine

•  

•  

• 3- Aldosterone act to:

• a) rise blood glucose level

• b) lowers blood glucose level

• c) Increases heart rate and stroke volume

• d)promote reabsorption of Na and excretion of K in kidneys

•  

•4-The hormone which stimulates contraction of uterus and mammary gland cells is called;•a-LH b-Oxytocin

•c-FSH d-Estrogen

• •5-The hormone which lowers the blood glucose level is;

•a-Glucagon b-Glucocorticoid

•c-Insulin d-Adrenaline

• •6-Melatonin is a hormone produced by the;

•a-Anterior pituitary b-Posterior pituitary

•c-Pineal gland d-Adrenal gland.• 

• 7-FSH(Follicle Stimulating Hormone)and LH(Luteinizing Hormone)are tropic hormone that are known as----------•a-Androgen b-Prostaglandins

•c-Gonadotropins d-Adrenaline.• 

•8-The anterior lobe of the pituitary produces and secretes ------hormones;•a-Seven b-Six

•c-Two d-None of the above.•9-Which of the following pairs of hormones do not have antagonistic (opposite) effects:

•a)- insulin & glucagon b)- PTH & calcitonin

•c)- epinephrine & glucagon d)- all of the above

• •10-Which of the following glands shows endocrine and exocrine function:

•a)- thyroid b)- pineal •c)- pancreas d)- all of the above