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Case Based LearningGLANDS

BYDr Abdul Waheed Ansari

Chairperson & Professor of Anatomy,RAK COMS

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The learning out comes for the glands are • Demonstrate the ability to identify and classify different types of

glands like endocrine/exocrine glands-mixed/serous and mucus glands-simple and compound glands and describe their functions and properties.

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A case of mumps

• A 5 year child was having fever and difficulty in swallowing and complaining of pain on opening of his mouth since 5 days.

• On examination there was a swelling around the left ear.

• The pediatrician diagnosed as viral parotitis-Mumps

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Inflammation and infection of salivary glands are called as viral parotitis- mumps

• Glands are the epithelial tissues derived from all three germ layers embryologically.

• Glands derived from ectoderm are skin glands, parotid gland and sweat glands.

• Pancreas and liver are glands derived from endoderm.

• Kidneys, suprarenal and gonads are derived from mesoderm.

• Mumps is a virus infecting the salivary glands, usually during childhood, 5-15 years of age.

• There are 3 major salivary glands, parotid is the largest, submandibular and sublingual.

• According to the type of secretions, the salivary glands are of three types, predominantly serous gland-parotid. Predominantly mucus-sublingual and mixed gland –submandibular.

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A secretory unit is called the acinus.

• A serous acinus is characterized by producing watery secretions.

• Each acinus is having simple columnar/pyramidal cells resting on a basement membrane.

• Their nuclei are rounded and situated centrally, the cytoplasm is having many eosinophilic granules.

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A Mucus acinus • Sublingual gland is a

predominantly mucus salivary gland.

• A mucus acinus has pyramidal cells with vacuolated cytoplasm and rod shaped nuclei at the basal level.

• The cytoplasm is basophilic.

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A mixed acini are seen in submandibular gland

• Some acini are serous in nature secreting watery secretions.

• Some acini are mucus caped with serous acinus-called serous demilunes.

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Glands can be classified into endocrine and exocrine glands-endocrine glands have no ducts where as exocrine glands sent out their secretions through duct systems

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A case of endemic goiter

• Thyroid gland is an endocrine gland situated at the wind pipe in the neck.

• It secretes thyroid hormones, thyroxin.

• If it excretes more it causes swelling and toxic effects as protruding eyes.

• The endocrine glands sends out their secretions directly into the blood circulations.

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A goblet cell is a unicellular gland

• A goblet cell is a modified cell producing mucus secretions.

• It is a flask shaped cell, mucus ejecting out from the apical surface.

• Trachea has pseudostratified columnar epithelium having ciliated and secretory goblet cells.

• The cilia will move the mucus and traps the dust particles.

• Goblet cells are also seen in mucus lining of large intestines.

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Mechanism of SecretionMerocrine Apocrine Holocrine

Expelled by exocytosis Uses membrane vesiclesEntire secretory cell lost, as plasma membrane breaks to release product

Only secretory product is lostSweat glands are merocrine and apocrine. Merocrine sweat glands are found on palms and other body areas.

Secretory product and some membrane lostApical portions are lost in secretions. Apocrine sweat glands are found in armpits, nipples and groin. They produce viscus sweat and it smells because of bacterial actions.In lower animals, this smell attracts the opposite sex during breeding seasons.

Sebaceous glands use this method

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Apocrine glands-sweat glands

Holocrine gland-sebaceous glandThe entire cell cytoplasm is destroyed in the secretions

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Why should Glandular Epithelial Cells be studied?

Adenocarcinoma, a malignant tumor of the glandular epithelium, accounts for 40% of all lung cancer, making it the most common type.This patient enjoyed smoking for 40 years but his bad luck! Just 3 months back he came to OPD with C/O chest pain, cough and hemoptysis, his radiograph showed white opacity involving whole upper lobe of right lung. After histopathological examination he was diagnosed with adenocarcinoma of right lung and radiotherapy was started.

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The largest gland in our body is liver

• It is both an endocrine as well as exocrine gland. The exocrine part is the bile secretion produced by hepatocytes and drain by biliary tract and stored in to gall bladder.

• Liver detoxifies the blood to rid it of harmful substances such as alcohol and drugs.• Stores some vitamins and iron.• Stores the simple sugar glucose• Converts stored sugar to usable sugar when the body’s sugar (glucose) levels fall

below normal.• Breaks down hemoglobin as well as insulin and other hormones• Converts ammonia to urea, which is vital in metabolism• Destroys old red blood cells

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A case of jaundice

• Hepatitis is an inflammation of the liver. It may be caused by drugs, alcohol use, or certain medical conditions.

• But in most cases, it's caused by a virus.

• This is known as viral hepatitis, and the most common forms are hepatitis A, B, and C.

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The pancreas is another endocrine and exocrine gland associated with digestive system

The endocrine part of pancreas is the islets of Langerhans

The exocrine part of pancreas secretes the enzymes

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The reproductive glands are testes and ovaries• Testes are found in male individuals.• The exocrine part produces sperms

and carried by ducts, seminiferous tubules, vas deferens and spermatic cord.

• The endocrine part is interstitial cells that produce the male hormones.

• The ovaries are found in female bodies. They produce ova and carried by uterine tubes.

• The endocrine part of ovaries produce female hormones, estrogens.

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Cryptorchidism is the absence of one or both testes from the scrotum. It is a common birth defect regarding male genitalia

Polycystic ovary is one of the commonest reason for female sterility

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The prostate gland is found only in male subjects• The prostate secretes fluid that

nourishes and protects sperm.• During ejaculation, the prostate

squeezes this fluid into the urethra, and it’s expelled with sperm as semen.

• Prostate gland rest over the neck of the bladder.

• The urethra passes through the prostate. During old age this gland enlarges and obstruct the passage of urine, causing urine retension.

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The mammary glands are functional in female

• It is a modified sweat gland.• It lies in superficial fascia.• Breast cancer is most common in

female patients.• Benign tumors may also arise

from breast tissue.

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Lymph nodes are small nodular glands present through out the body

• They drain the lymphatics from one region/organ/part to another.

• Lymph nodes are named according to the region they are located.

• Cervical if they are in the neck.• Axillary lymph nodes are found in

the armpits.• Inguinal lymph nodes are in the

groin region.

• Abdominal groups of lymph nodes are found in the abdominal cavity.

• Mediastinal groups are in the mediastinum-a median region between both the lungs.

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Kidneys are the excretory glands

• They are found in the lumbar regions.

• They filter the blood and removeImpurities and form urine.• They also produce hormones-

renin and erythropoietin.• Renin helps in regulation of blood

pressure.• Erythropoietin will stimulates

blood formation.

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The pituitary gland and pineal gland are found in the cranial cavity• The pituitary gland controls all

other endocrine glands.• Hence it is called as master

gland.• The pineal gland is a small gland

in the brain. It produces melatonin, a serotonin derived hormone, that affects the modulation of sleep patterns.

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The suprarenal glands are located at the upper poles of each kidneys

• They are responsible for regulating the metabolism of minerals.

• The cortex produced gonadotropin, the sex hormones.

• The medulla of adrenal glands produce adrenaline that make the body ready to fight and flight situation.

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References

• http://www.bio.davidson.edu/people/kabernd/berndcv/lab/epithelialinfoweb/Glandular%20Epithelium.html.

• http://www.rci.rutgers.edu/~uzwiak/AnatPhys/APFallLect5a.html• http://www.dartmouth.edu/~

anatomy/Histo/lab_4/skin/DMS194/popup.html• Clinically oriented Anatomy-6th edition-Keith Moore ( 98-

99,854,961,943,294,982.)