Lamellar bodies

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Micrograph of lamellar bodies in lung tissue

Lamellar bodies are specialized organelles found in certain cell types, most notably in type II alveolar cells of the lung and in keratinocytes of the skin. These organelles play a crucial role in the production and secretion of surfactant in the lungs and in the formation of the skin's protective barrier.

Structure

Lamellar bodies are characterized by their unique, concentric, lamellar structure. They are membrane-bound organelles that contain tightly packed layers of lipids and proteins. In the lungs, these lipids are primarily composed of phospholipids, which are essential for reducing surface tension in the alveoli.

Function

In the Lungs

In the pulmonary system, lamellar bodies are responsible for storing and secreting pulmonary surfactant. Surfactant is a complex mixture of lipids and proteins that reduces surface tension in the alveoli, preventing their collapse during exhalation and ensuring efficient gas exchange. The secretion of surfactant from lamellar bodies is a critical process for normal respiratory function, particularly in newborns.

In the Skin

In the epidermis, lamellar bodies are involved in the formation of the skin's barrier function. They secrete lipids and enzymes that contribute to the formation of the stratum corneum, the outermost layer of the skin. This barrier is essential for preventing water loss and protecting against environmental insults.

Clinical Significance

Disorders in lamellar body function can lead to significant clinical conditions. In the lungs, insufficient surfactant production can result in respiratory distress syndrome (RDS), particularly in premature infants. In the skin, defects in lamellar body secretion can contribute to conditions such as ichthyosis and other barrier-related skin disorders.

Related Pages

• Surfactant
• Type II alveolar cells
• Respiratory distress syndrome
• Keratinocytes
• Stratum corneum