أحياء لغات – The Thyroid Gland للصف الثالث الثانوى 2016

The Thyroid Gland

.The gland lies in the neck in front of and in close contact with the trachea	site
.The colour is slightly red .The gland consists of two lobes connected together by an isthmus	Structure
.The gland secretes the hormone Thyroxin .Iodine is essential for the formation of this hormone :Thyroxin has many effects on different parts of the body. As for example It affects and stimulates physical and mental growth and development - It affects the basal metabolic rate - It increases the absorption of carbohydrates (Glucose) from the intestine- It maintains healthy skin and hair -	function
The gland secretes another hormone called Calcitonin which decreases the Calcium level in the blood by decreasing its release form bones prevents its absorption from the bones -	Function

Goiter

The enlargement of the thyroid gland associated with abnormal activities of the gland

- :There are two types of goiter

Simple goiter

Cause

.It occurs due to Iodine deficiency in food, water, and air

Treatment

.The treatment involves administration of Iodine supplement in food

Exophthalmic goiter

.It’s the enlargement of the gland with protrusion of the eye balls

.(It results from hyper secretion of the gland (hyperthyroidism

:A) Hyper secretion of Thyroxin leads to

.An increase in food oxidation and metabolic rate -

.loss of weight -

.increase in heart beats and nervous irritability -

.Protrusion of eye balls -

The treatment of this case is by either surgical removal of a part of the gland or by the use of other medications to

.suppress the gland

:B) Hypothyrodism (simple goiter)

Cause

Hypothyroidism is the decrease in the secretion of the thyroxin hormone from the gland

The symptoms resulted depends on the age

P.O.C	Cretinisme	Myxodema
Causes	:Hypothyroidism in children	:b) Hypothyroidism in adults
Symptoms	Cretinism is characterized by 1- Retardation in physical and mental growth associated with large head, short stature, short neck. 2- Permanent mental retardation . 3- A delay in sexual maturity.	Myxodema is characterized by 1- dry skin, loss of hair, 2- decreased mental and physical activity, 3- weight gain, and obesity, 4- decreased basic metabolic rate and cold intolerance, decreased heart beats, and 5- rapid fatigability. The treatment is by regular consultation of a specialist and by administration of Thyroxin or gland extracts.
v The treatment of Hypothyrodisme	v Is regular consideration of a specialist . v By adminsteration of thyroxin or glands extracts By adding iodine to food & salts &water	v Is regular consultation of a specialist v By administration of thyroxin or gland extracts v By adding iodine to food & salts &water

Third: The Parathyroid Glands

Hypersecretion of parathormone (Hyperparathyrodism)

Hyposecretion of parathorome (hypoparathrodism)

Symptoms

a)Increase in the Calcium level in blood.

b) As most of the Calcium is released from bones, the condition is associated with increase bone resorption and the bones become fragile and liable for bending and fracture

a)Painful convulsions and muscle spasms (as a result of decrease Calcium in blood)

b) Increase excitability of the nervous system.

Note ) Two hormones (parathormone from parathyroid & Calcitonine from thyroid gland) are responsible for the control of calcium level in the blood

Fourth: The Adrenal (Suprarenal) Glands

It secretes the two hormones: Adrenaline and Nor adrenaline

Glucocorticoids

Mineralcorticocoids

Sex Hormones

Hormones secreted

Includes Cortisone & corticosterone

Includes aldosterone hormones

vThe male sex hormone is Testosterone .

vThe female sex hormones are Estrogen and Progesterone.

Although the main source of sex hormones are the testes in males and the ovaries in females(Hormones with similar effects are secreted from the adrenal cortex.)

Main function

the main function of which is to regulate carbohydrates (Glucose) metabolism in the body

1- Plays an important role in mineral metabolism and balance in the body.

2- This hormone increases re-absorption of Sodium and increases the excretion of Potassium form the kidney tubules.

If tumorous in the adrenal cortex, or any condition that may lead to disturbance in the balance between sex hormones secreted from the gonads and those secreted from the adrenal cortex, this leads to

1-Musculanization in females and

2-Feminization in males and atrophy of gonads in both sexes.

:Hormones of the medulla

It secretes the two hormones: Adrenaline and Nor adrenaline

Fifth: The Pancreas

?????????The pancreas is considered as a mixed gland with exocrine&endocrine secretions Because;- Why

The exocrine secretion is in the form of pancreatic juice secreted from pancreatic acini through pancreatic duct into the duodenum

The endocrine secretion can secrete hormones directly in blood from groups of cells called Islets of Langerhans which contain two types of cells

Alpha cells	Beta cells
Small in number and secrete a hormone called Glucagon.	Represents the majority of cells and secrete a hormone called Insulin.

Function of Insulin

Function of Glucagon

The Insulin decreases the Glucose level in the blood through:

a) It stimulates the oxidation and utilization of Glucose by the cells, as it is important for transport of all monosaccharides (except Fructose) across the cell membrane.

b) It stimulates the conversion of Glucose to Glycogen (to be stored in the liver and muscles) or to lipids.

C) Its decrease in secretion leads to diabtes mellitus .

It antagonizes the action of Insulin:

Glucagon increases the Glucose level in the blood through the conversion of Glycogen to Glucose (only in liver).

????What will happen if

Decrease in the secretion of Insulin:

Leads to a disease called Diabetes Mellitus, characterized by disturbance in the metabolism of carbohydrates (Glucose) and lipids.

The patient with Diabetes Mellitus complains of :-

1- increase Glucose level in the blood associated with the abnormal appearance and excretion of Glucose in urine .

2- The excretion of a large volume of water which explains the symptoms of continuous thirst sensation and excessive micturition.

(Sixth: Sex Glands (The Gonads

A) Male sex hormones :- Are called androgens

:Female sex hormones

Oestrogen

Progestrone

Relaxin

Source

It is secreted from the graafian follicle of the ovary or from the placenta during pregnancy.

It is secreted from the corpus luteum of the ovary

It is secreted from the corpus luteum, placenta, and uterus.

Action

It helps the appearance of the female secondary sexual characters such as the increase in the size of the breasts and regulates the menstrual cycle

It is important during pregnancy as it regulates the vascularity of the uterine wall and prepares it to receive the embryo.

In addition, progesterone is responsible for the changes taking place in mammary glands during pregnancy.

Itcauses relaxation of the muscles of the pelvis at the end of pregnancy to facilitate the process of delivery.

Seventh: Gastrointestinal Hormones

In addition to the exocrine function of the mucous membrane lining the alimentary canal

It secretes also a group of hormones which regulate and stimulate the different parts of the alimentary canal to

secrete the digestive juices

:Examples of these hormones are

(Gastrin: (secreted from the stomach wall -

( Secretin and cholecystokinin: (secreted from the intestinal wall

أحياء لغات – The Thyroid Gland للصف الثالث الثانوى 2016

The Thyroid Gland

.The gland lies in the neck in front of and in close contact with the trachea

site

.The colour is slightly red

.The gland consists of two lobes connected together by an isthmus

Structure

.The gland secretes the hormone Thyroxin

.Iodine is essential for the formation of this hormone

:Thyroxin has many effects on different parts of the body. As for example

It affects and stimulates physical and mental growth and development -

It affects the basal metabolic rate -

It increases the absorption of carbohydrates (Glucose) from the intestine-

It maintains healthy skin and hair -

function

The gland secretes another hormone called Calcitonin which

decreases the Calcium level in the blood by decreasing its release form bones

prevents its absorption from the bones -

Function

Goiter

The enlargement of the thyroid gland associated with abnormal activities of the gland

- :There are two types of goiter

Simple goiter

Cause

.It occurs due to Iodine deficiency in food, water, and air

Treatment

.The treatment involves administration of Iodine supplement in food

Exophthalmic goiter

.It’s the enlargement of the gland with protrusion of the eye balls

.(It results from hyper secretion of the gland (hyperthyroidism

:A) Hyper secretion of Thyroxin leads to

.An increase in food oxidation and metabolic rate -

.loss of weight -

.increase in heart beats and nervous irritability -

.Protrusion of eye balls -

The treatment of this case is by either surgical removal of a part of the gland or by the use of other medications to

.suppress the gland

:B) Hypothyrodism (simple goiter)

Cause

Hypothyroidism is the decrease in the secretion of the thyroxin hormone from the gland

The symptoms resulted depends on the age

P.O.C

Cretinisme

Myxodema

Causes

:Hypothyroidism in children

:b) Hypothyroidism in adults

Symptoms

Cretinism is characterized by

1- Retardation in physical and mental growth associated with large head, short stature, short neck.

2- Permanent mental retardation .

3- A delay in sexual maturity.

Myxodema

is characterized by 1- dry skin, loss of hair,

2- decreased mental and physical activity,

3- weight gain, and obesity,

4- decreased basic metabolic rate and cold intolerance, decreased heart beats, and

5- rapid fatigability. The treatment is by regular consultation of a specialist and by administration of Thyroxin or gland extracts.

v The treatment of Hypothyrodisme

v Is regular consideration of a specialist .

v By adminsteration of thyroxin or glands extracts By adding iodine to food & salts &water

v Is regular consultation of a specialist

v By administration of thyroxin or gland extracts

v By adding iodine to food & salts &water

Third: The Parathyroid Glands

Hypersecretion of parathormone (Hyperparathyrodism)

Hyposecretion of parathorome (hypoparathrodism)

Symptoms

a)Increase in the Calcium level in blood.

b) As most of the Calcium is released from bones, the condition is associated with increase bone resorption and the bones become fragile and liable for bending and fracture

a)Painful convulsions and muscle spasms (as a result of decrease Calcium in blood)

b) Increase excitability of the nervous system.

Note ) Two hormones (parathormone from parathyroid & Calcitonine from thyroid gland) are responsible for the control of calcium level in the blood

Fourth: The Adrenal (Suprarenal) Glands

It secretes the two hormones: Adrenaline and Nor adrenaline

Glucocorticoids

Mineralcorticocoids

Sex Hormones

Hormones secreted

Includes Cortisone & corticosterone