The Pineal and Thymus Glands

By:

Irene ProtopapasCarissa Rivera

Jaclyn Robustelli

Pineal Gland – The Third Eye

– small, cone-shaped gland (about the size of a pea ~ 8mm)

– has a reddish-gray color– located near the center

of the brain and hangs from the roof of the third ventricle

– it is tucked in a groove where the two rounded thalamic bodies join

– part of the epithalamus

Hormones of the Pineal Gland

– produces many chemical substances– the only hormone secreted in substantial amounts is melatonin– melatonin is made from the amino acid tryptophan– the synthesis and release of melatonin are stimulated by

darkness and suppressed by light – levels of melatonin in the blood are highest prior to bedtime– melatonin also helps regulate other hormones in the body

Molecular Properties

– The pineal gland is made up of glandular epithelium.

– Its hormones are secreted directly in the blood vessels that are connected to the glands.

– The soft tissue of the pineal gland contains high levels of fluoride.

– The hard tissue of the pineal gland is made up of hydroxyapatite crystals which also accumulates fluoride.

Molecular Images

Microcyrstals of gland

Functions

- causes feelings of sleepiness- converts nervous system signals into

endocrine signals- regulates endocrine functions- secretes the hormone melatonin

(which regulates sleep/wake patterns)- appears to play a major role in sexual

development and metabolism- regulates the sex glands

Organ Interactions

- It is attached to the posterior wall of the third ventricle of the brain.

- It regulates the sex organs (mostly during puberty) - the ovaries in women and the testes in men.

- If the pineal gland did not function correctly, puberty could be started sooner or later than the normal age.

Pineal Gland Diseases1) Melatonin deficiency

- It is a lack of melatonin produced in the pineal body.- It is linked to insomnia – a person is unable to sleep.  - Signs of melatonin deficiency are “insomnia, anxiety, elevated estrogen/progesterone ratio, immune suppression, and lowered normal body temperature.”  - Without melatonin, the aging process also increases.- To find out if a person has a melatonin deficiency, a person is usually tested by saliva or plasma tests. In order to gain melatonin back, one must decrease exposure to artificial light or radiation (tanning beds) and try to live less stressfully. Cherries and cherry juice have also been known to help gain melatonin back. 

Pineal Gland Diseases2) Melatonin excess (opposite of melatonin

deficiency)- There is too much melatonin being produced.- It is usually associated with Seasonal Affective Disorder (SAD) – which is a form of depression that people usually deal with on and off during different seasons.  - When a person has too much melatonin in the body, he/she usually has a lowered estrogen/progesterone ratio, low thyroid and adrenal function, and hypotension (lowered blood pressure).- To help balance the amount of melatonin the pineal body produces, a person with excess melatonin should try to have a certain amount of time outside in the sun, avoid working at night, and try to manage stress. Also a person should avoid caffeine and alcohol and try to intake essential fatty acids such as omega 3. 

Pineal Gland Diseases3) Pineal tumor (cancer)

- The cause of this type of cancer is unknown.  - This tumor usually presses over the aqueduct of Sylvius which helps cause CSF to flow through the brain.- The blockage usually causes headache, nausea and vomiting, seizures, memory disturbances, and visual changes.  - The pineal tumor also affects eye movements, causing inability to focus, double vision, and impairing eye movements.  - This cancer can be treated with surgery, radiation, chemotherapy, and immunotherapy. 

The Thymus Gland– a soft, flattened, pink-grey

organ – located in the upper

thorax, in front of the heart and posterior to the sternum

– composed of two identical lobes

Hormones– secretes the hormone

thymosin which is made from peptides

– it promotes the development of the immune system by producing a type of white blood cell known as a T-lymphocyte (T-cells)

– developing T-cells are referred to as thymocytes

T-Cell

thymosin

Molecular Anatomy of Thymus

• It is made of thymic cortical epithelial cells, thymic medullary epithelial cells, and dendritic cells

Functions- the processing and maturation of

t-cells- help cells recognize and destroy

invading bacteria, viruses, abnormal cell growth such as cancer, and foreign tissue

- If the thymus is taken out, a person has little to no immunity

Organ Interactions

- The thymus interacts with the immune system.

- Organs of the immune system: Lymph Nodes, Spleen, Bone marrow

- Any area of the body that has foreign substances that the t-lymphocytes (white blood cells) from the thymus will try to destroy

Thymus Gland Diseases1) Myasthenia Gravis

- This is a neuromuscular disorder in which voluntary muscles become very weak.  - Cause: immune disorders- Symptoms: difficulty swallowing, paralysis, and difficulty carrying out many every day activities such as climbing stairs.  - There is no cure for this disease, but there are temporary treatments for it such as medicine like neostigmine or pyridostigmine that help make the disease easier to live with- A thymectomy (removal of the thyroid) can be carried out so that the person with this disease can take less medicine

Thymus Gland Diseases2) DiGeorge Syndrome

- It is when a person does not have a thymus gland in his or her body.- Cause: absence of chromosome 22- Many people with this disease are treated by surgery so that a false thymus will be put into their body. This will sometimes help an immune reconstruction.   

Thymus Gland Diseases

3) Thymic cyst- Two kinds of cysts: unilocular and multilocular- Unilocular cysts are usually small, usually found in the neck. They are benign.  - Multilocular cysts can be cancerous, and have to be removed through a thoracotomy.  This type of cyst can be caused by the HIV infection when inflammation occurs.