ENDOCRINE SYSTEM:Pineal Gland, Pituitary Gland, Dwarfism

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Introduction to Psychology PSY101

Lesson 14

ENDOCRINESYSTEM

Endocrinesystem is a collection of glandsthat produce hormones thatregulate body's growth,metabolism,

andsexual development and function.The hormones are releasedinto the bloodstream and transported to

tissuesand organs throughout the body.

Althoughthere are eight major endocrine glandsscattered throughout the body, they are still considered to

be one system because they havesimilar functions, similar mechanisms of influence, and manyimportant

interrelationships.

· Endocrineglands are known as the "Managers of Human Body".

· Endocrinesystem is the system in which a number of glands secrets numeroushormones directlyinto

the blood stream whichregulate:

oBody'sgrowth

oMetabolism

oSexual development and functions, and

oOthervital functions of the body

Endocrineglands are ductless glandsthat secrete their hormonesdirectly into the bloodstream.

Hormonesact as chemical messengercontrolling various functions, reaching to the tissues and

othervital organs of the body.

Pineal Gland

· The pineal gland, also known as pineal body, is found in the brainstem.

· It is small and cone-shaped in structure

Mainfunction:

oAffectsreproductive development

oDailyphysiologic/ biologicalcycles

Pituitary Gland

Sizeand shape

It is a small gland__ diameter of about 1 centimeter or size of a pea.

Location

· It is connected with the hypothalamus by a slender stalk and also surrounded by bone.

· Secretes a number of different hormones thatinfluence/affect various other endocrine glands.

· There are two distinguishableregions in the gland thathave different secretionsand functions:

a. The anteriorlobe

b. The posterior lobe

a. Hormones of Anterior Lobe

Growth Hormone: Proteinthat regulates and alsostimulates the:

· growth of bones,

· muscles,and other organs of the body by promoting proteinsynthesis.

The effect of this hormone is important and very much apparent because it affects height.

Growth Hormonal Problems

Dwarfism

If there is very little or no secretion of this hormone in a child, then the child may become a pituitary

dwarf__small in stature.

Gigantism

· If there is too much secretion of this hormone in the body, thenthere is exaggerated bone

growth in a person and the personbecome exceptionally tall or a giant.

Introduction to Psychology PSY101

Thisrare condition is usuallycaused by a pituitary tumorand can be treated by removing the

tumor.

When the pituitary gland fails to produceadequate amounts of growth hormone, a child's growth

in height is impaired/ disturbed.

Hypoglycemia (low blood sugar) mayalso occur in children whohave deficiency of this growth

hormone __ affects particularly infants and young children with this condition.

Thyroid-stimulating hormone: Affects the glandular cells of the thyroid so that it secretesthyroid

hormone. The thyroid gland becomeenlarged and secretes toomuch thyroid hormone if

there is hyper secretion of thyroid- stimulating hormone.

Adrenocorticotropic hormone: Cortical hormones especially cortisol aresecreted when it reacts with the

receptorcells in the cortex of the adrenalgland.

Gonadotropic hormones: Regulate the development, growth, andfunction of gonads andovaries by

reacting along with receptor cells present in these organs.

Prolactin Hormone: Helps in promoting the development of glandular tissues in the female breastsduring

pregnancyand as a result stimulatesmilk production after the birth of the infant.

Hormones of the Posterior Lobe

Thesehormones are:

Antidiuretic hormone

· Helps in the reabsorption of water by the kidney tubules__ as a result of which less amount of

water is lost from the body as urine.

· This system/ mechanism conserves waterfor the body.

ii.

Oxytocin

· Helps in the contraction of smooth muscles in the walls of the uterus.

· It also stimulates the ejection of milkfrom the lactating breast.

3. Hypothalamus

· Part of the central nervous systemthat is involved in controllingand activating involuntary functions of

the body such as,

· Hormonalsystem

· Otherbody functions as well__ regulating sleep and stimulating appetite

ThyroidGland

Type,Location and Lobes

· Veryvascular organ and is located in the neck.

· Consists of two parts/ lobes, one on each side of the trachea,

justbelow the larynx or voice box.

· Thesetwo lobes are connected by a narrow band of tissue,

called the `isthmus'.

· Thisgland consists of follicles, whichproduce thyroxin and

triiodothyroninehormones.

· Thesehormones contain iodine--- about 95% of most

functioninghormone is thyroxin and the remaining 5% is

triiodothyronine__both require iodine fortheir synthesis.

· Secretion is regulated by a negative feedbackmechanism.

Calcitonin

· Secreted by Para follicular cells of the thyroid gland.

Introduction to Psychology PSY101

Opposes the action of the parathyroid glands by reducing the calcium level in the

blood.

If calcium level in the blood becomestoo high, calcitonin is secreteduntil calcium ion

levelsdecreases to normal.

IodineDeficiency

· Thyroidenlargement is called "goiter" or "iodine deficiencygoiter".

· If there is a deficiency of iodine in the body, then thyroid produceinsufficient

hormones required by the body__ causing the thyroid- stimulating hormone of the

pituitarygland (anterior lobe) to secreteits hormone. This results in the increase in size

of the thyroid gland but it is unable to make enough hormones,because it is lacking

the raw material for productioni.e. iodine.

Parathyroid Gland

Location,Type, Amount, Hormone

· Parathyroid gland consists of four smallmasses of epithelial tissuethat are embedded in the

connectivetissue capsule, on the posterior side of the thyroid glands.

· Secretes `parathyroid hormone' or `parathormone'.

· Mostimportant regulator of blood calciumlevels, secreted in response to low blood calciumlevels,

andits function is to increasecalcium levels in the body.

Deficiency/ insufficient secretion of parathyroid gland

· Insufficientsecretion of parathyroid hormone`hypoparathyroidisms', leads to increasednerve

excitability.

· Lowblood calcium level in the bodytriggers spontaneous and continuous nerve impulses, which in

turnstimulate muscle contraction.

Pancreas---Islets of Langerhans

· A long, soft organ thatlies transversely along

the posterior abdominal wall, posterior to the stomach,

andextends from the region

of the duodenum to the spleen.

a. Exocrine portion of this hormonesecretes

digestiveenzymes that are carried by a duct to

the duodenum

b. The endocrine portion consists of the pancreatic islets,and

c. secretes glucagons andinsulin.AlphaCells in Pancreatic

Islets

Secretehormone called `glucagons' when there is a low

concentration of glucose in the blood.

BetaCells in the Pancreatic Islets

After the alpha cells, beta cellssecrete hormone called `insulin' as a result of high concentration of glucose

in the blood.

Adrenal Gland

Synthesisand Location

· Developedfrom different embryonic tissues, it secretes various

hormones.

· Theadrenal/ suprarenal is a pairedgland and located near the

upper portion of eachkidney.

Division of Adrenal Gland

Eachgland is divided into twoparts

a. An outer cortex and

b. An inner medulla

· The cortex and medulla of the adrenalgland are just like the anterior and posterior lobes of the

pituitarygland.

Introduction to Psychology PSY101

Theadrenal cortex is essential to lifebecause it has very importantfunctions to perform, but the

medullamay be removed with no life-threatening effects.

Hypothalamus effects and influences bothportions of the adrenal glandbut it involvesdifferent

mechanismsi.e. adrenal cortex is regulated by negative feedback whichinvolves hypothalamusand

adrenocorticotropic hormone.

Medulla is regulated by nerve impulses of hypothalamus.

Hormones of the Adrenal Cortex

· Theadrenal cortex consists of threedifferent portions/ regions,each region produce different type of

hormones.

· Chemically,all these cortical hormonesare steroid.

a. Mineralocorticoids

· Secreted by the outermost region of the adrenal cortex.

· Themain/ principal hormone of mineralocorticoid is aldosterone, whichacts to store/conserve

sodiumions and water in the body.

b. Glucocorticoids

· Secreted by the middle region of the adrenal cortex.

· Themain/ principal hormone of glucocorticoid is cortisol, which increases blood glucose/ sugar

level in the body.

c. Gonadocorticoids

· Alsoknown as the sexhormones.

· Theseare secreted by the innermost region of the adrenal cortex.

· Adrenal cortex hormones, androgens (malehormones) and estrogens(female hormones),are

secreted in minimal amounts in bothsexes, but their effect is usually influenced by the hormones

from the testes andovaries.

· In females, the masculinization effect maybecome more evident after menopause. Thisoccurs

because the estrogen levels from the ovaries decrease.

Hormones of Adrenal Medulla

· Develops from neural tissues.

· Secretestwo types of hormones,

oEpinephrineand

oNor epinephrine

Theseare secreted in response to stimulation by sympathetic nerve,especially duringstressful

situations.

Lack of hormones from the adrenalmedulla produces no significant effects,

Hypersecretion, e.g., in case of a tumor, results in prolonged or continual sympatheticresponses.

Gonads

· Primary reproductive organs are testes in the male and the ovaries in the female.

· Theseorgans are responsible forproducing the sperm and ova,but they also secreteother

hormones,and that is why they areconsidered to be endocrine glands.

Testes

· Malesex hormones (as groups)are called androgens of which the most important andinfluential is

`testosterone';secreted by the testes.

· Small amount is also produced by the adrenal cortex.

· Production of testosterone begins before birth.i.e. during fetal development that continues for a

short time after birth, nearly ceasesduring childhood, and thenresumes at puberty.

Introduction to Psychology PSY101

· This steroid hormone is responsiblefor:

O The growth and development of the male reproductiveorgans.

O Increase in the size of skeletonand muscular growth.

O Larynx enlargement, accompanied by voice changes.

O Growth and distribution of body hair.

O Increased male sexualdrive.

· It'ssecretion is controlled andregulated by a negative feedbacksystem and involves release of

hormonesfrom the hypothalamus and gonadotropins from the anteriorpituitary.

Ovaries

· Twogroups of female sexhormones are produced in the ovariesi.e.,

oEstrogensand

oProgesterone

Contribute to the development and function of the female reproductive organsand sexcharacteristics

Estrogen

Estrogen(on the onset of puberty) activates/ promotes:

o Development of female bodilycharacteristics.

o Distribution of fats in the body.

o Maturation of reproductive organs .

ii.

Progesterone

Causes the uterine lining to become thick, preparing uterus forpregnancy.

· Togetherboth progesterone andestrogen are responsible for a number of changes

occurring in the uterus.

Other Endocrine Glands

· In addition to the major endocrine glandsand their system, thereare various other organs,which are

involved, in some hormonal activity or function. These include:

Thymus

ii.

Stomach

iii.

Smallintestines

iv.

Heart,and

Placenta

i. Thymosin

Hormone produced by the thymus gland, whichhas an important role in the development of the body's

immune system.

ii.Gastrin

· Gastric mucosa (lining of the stomach)produces a hormone, called gastrinthat is secreted when the

food is present in the stomach.

· Stimulates the production of `hydrochloric acid' and the enzyme `pepsin', whichare involved in the

digestion of food.

iii.

Secretin and Cholecystokinin: Themucosa of the small intestine secretesthese hormones.

· Secretinstimulates the pancreas to produce a neutralizing agent__ bicarbonate-rich fluidthat

neutralizes the stomach acid.

Cholecystokinin

· Stimulatescontraction of the gallbladder, whichresult in the releases of bile.

· Alsoactivate the pancreas to secretedigestive enzyme.

· AtrialNatriiuretic Hormone, or Atriopeptin

· Heartalso function as an endocrine organ

Introduction to Psychology PSY101

In addition to its major role of pumping blood, has specialcells in the wall of the upper chambers

of the heart `atria', secreteshormone called atrial natriiuretic hormone, or atriopeptin.

Placenta

Develops in the pregnant female

It is a source of nourishment and gaseousexchange for the developingfetus

Alsoserves as a temporary endocrine gland

Chorionic gonadotropin: One hormone that placentasecretes in humanbeings.

Diseases Resulting from Abnormal Secretion of Endocrine Glands

· Toomuch or too less secretions of endocrine glands can be harmfulfor the body.

· Thesesecretions can be treated by controlling the over production,providing the essentialsfor

production, or replacing hormones.

· Some of such abnormalities are:

1. Cretinism

· Occursdue to the lack of thyroidgland secretions.

· Prevalent mostly in Southern France, Spain, Italy,and Switzerland.

· Itssymptoms are:

O Marked dwarfism and imbecility.

O The adult who remains untreated remains about as large as a four-year-old child and has the mental

level/ intelligence of that age.

O Hair becomes coarse.

O Feeling no or littleemotion.

2. Hyperthyroidism

· Occurswhen thyroid becomes overactive

The major symptomsare:

· Personbecomes restless andthin

· Showsexcessive emotionality

· Sleeplessness

· Rapidheart beat

· Tremors

· Thyroidbecomes swollen (goiter)

· Nervousness

· Excessivesweating,

· Bloodpressure

· Protrudingeyes

In children and teens,GRAVES'DISEASE usuallycauses this condition,

an autoimmune disorder in which specific antibodies produced by the child's immune system stimulate the

thyroidgland to becomeoveractive.

Method of treatment

· Removal of some of the glandsurgically.

· Radiotherapy

In early times, the entire glandwas also removed, but by doing this, the chances of myxoedemabecome

probable.

· With the proper dosage of the glandsubstance i.e. iodine, the patient remains normal, butwith low

dosage the person becomes dull and stupid. When too much is given, become unstable and

emotional.

3.Hypothyroidism

Condition in which the levels of thyroidhormones in the blood are abnormally low. Symptoms are:

· Slowsbody processes that maylead to fatigue

Introduction to Psychology PSY101

Slowheart rate

Dry skin

Weight gain

Constipation

In children, it may result in

Slowgrowth and delayedpuberty

"Hashimotothyroiditis" results from an autoimmune processthat damages the thyroid andblocks

thyroidhormone production/ secretions. It is the most common cause of hypothyroidism in children.

· Infantscan also be born with an absent or underdeveloped thyroid gland, resulting in

hypothyroidism.

· Thecondition can be treatedwith oral thyroid hormonereplacement.

4. Myxoedema

· Occurs particularly in women __also due to a deficiency in the thyroid gland'ssecretion.

· When it occurs, the patient, who wasearlier a bright, capable,energetic person, full of the eager

purposesand emotions of life, graduallybecomes,

O Dull

O Stupid O Apathetic

O Without fear, anger, love,joy or sorrow

O Without purpose or striving

O Hair becomes coarse andscanty

O Skin thick and swollen(hence the name of the disease)and

O Various changes take place in the sweat secretion, the heart action, etc

5.Acromegaly

Occursdue to an abnormality/ change in the pituitary gland.

The major and apparent symptomsare:

O Melancholic tendencies

O Loss of memory and

O Mental and physicaltorpor

O Profound effect on character and personality, exclusive of intelligence, andthat of sex glands

6.Adrenal insufficiency

· Condition occurring due to the decreased function of the adrenal cortex, andconsequently

underproduction of adrenal corticosteroid hormones.

· Thesymptoms of adrenal insufficiency may include,

oWeakness

o Fatigue

oAbdominal pain

oNausea

oDehydration

oSkin changes

Treatment

Doctors treat adrenal insufficiency by givingreplacement corticosteroid hormones.

7. Cushing syndrome

· Whenexcessive amounts of glucocorticoid hormones are secreted in the body,

then it causes this syndrome.

Introduction to Psychology PSY101

If this condition is due to a tumor in the pituitary gland thatproduces excessive

amounts of corticotropin and stimulates the adrenals to overproduce

corticosteroids,then it is known as Cushingdisease.

In children, it most often occurs when a child has been given largedoses of

synthetic corticosteroid drugs (such as prednisone) to treat autoimmune diseases

such as lupus.

Symptomsthat may take years to develop include:

O Obesity

O Growth failure

O Muscle weakness

O Easy bruising of the skin

O Acne

O High blood pressure

O And psychologicalchanges

Treatment:

Depending on the specific cause, doctorsmay treat this conditionwith:

O Surgery

O Radiation therapy

O Chemotherapy

O Or drugs that block the production of hormones

8.Diabetes

Type 1 Diabetes

· Develops when pancreas fails to produce enough insulin.

· Symptoms include excessive:

oThirst

oHunger

oUrination,and

oweight loss

In children and teens, the condition is usually an `autoimmunedisorder"___ specific immune

systemcells and antibodies produced by the child's immune system thatattack and destroy the cells

of the pancreas that producesinsulin.

· Cancause long-term complications suchas:

O Kidney problems

O Nerve damage

O Blindness

O And early coronary heartdisease and stroke

Treatment

In order to control blood sugarlevels and reduce the risk of developing diabetes complications, children

with this condition need regular injections of insulin

Type 2 diabetes

In this, the body is unable to respond to insulin normally,like in type 1 diabetes

· Childrenand teens with this condition are overweight.

· It is also believed that excessbody fat plays a role in the insulin resistancethat

characterizes the disease.

· In recent years the rising prevalence of this type of diabetes in children played a crucial role

in increasing rates of obesityamong children and teens.Thesymptoms and possible

complications of type 2 are the same as those of type 1.

Introduction to Psychology PSY101

Some children and teens can control their blood sugar levelwith:

O Dietary changes

O Exercise

O Oral medications

O But many have need to take insulin injections likepatients with type 1 diabetes.

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