Body Membranes - Types and Function

What are Body Membranes?

 

Body membranes are thin pliable sheets or layers of tissue that cover the body, line body cavities, and cover organs within the cavity and line hallow organs.

 

Function of Body Membrane

 

The functions of the body membrane are-

 

1. Line body cavities

2. Cover surface

3. Separate or connect certain regions, structures, and organs of the body

4. Form protective sheets around organs

 

Know here what is tissue and what are types of tissue?

Classification of Body Membranes

They can be categorized into epithelial and connective tissue membranes.

 

1. Epithelial Tissue Membrane

The epithelial membrane is consists of epithelium tissue attached to a layer of connective tissue.

 

The types of epithelial tissue membrane are-

1. Mucous membrane; which contains glands

2. Serous membrane; which secretes fluid

3. Cutaneous membrane; which makes up the skin

 

2. Connective Tissue Membrane

A connective tissue membrane is formed only from connective tissue. 

 

Types of connective tissue membrane –

 

1. Synovial membrane

2. Periosteum (covers each bone)

3. Perichondrium (covers cartilage)

4. Meanings (covers brain and spinal cord)

5. Deep fascia (covers each skeletal muscle)

1. Epithelial Membrane

Epithelial membranes consist of epithelial tissue and supporting connective tissue that covers or line many internal structures and cavities.

Types of Epithelial Membrane

1. Mucus Membrane/ Mucosa

Mucus membranes line body passageways that open to the outside of the body. Many mucus membranes contain Goblet cells, which secrete a viscous substance called mucus.

Organs lined by mucus membrane have the most slippery surface.

 

For example,

1. Nasal cavity and oral cavities Tubes of respiratory

2. Lining of the urogenital tract

3. Lining of the digestive tract

4. Reproductive system

 

Note - Mucus membrane lining urinary bladder lacks mucus.

 

Function of Mucus Membrane

 

The key function of the mucus membrane is-

1. Mucus protects the lining membrane from drying and protects it from mechanical and chemical injury.

2. In the respiratory tract it traps inhaled foreign particles preventing them from entering the alveoli of the lung.

3. Secrete mucus

4. Provides lubrication

5. Help in absorption in the small intestine

6. Provides protection, and helps to trap and dispose of invading microorganisms.

2. Serous Membrane/Serosa

Serous membranes are the double membrane of loose connective tissue lined by simple squamous epithelium called Mesothelium.

The parietal layers lines cavity and the visceral layer surrounds the organ (viscera) within the cavity. Two layers are separated by serious fluid secreted by the epithelium. A serous membrane secretes a serous watery fluid called serous fluid.

 

Types of Serous Membranes

 

There are three sites where serous membranes are found-

1. Pleural

The pleura is the serous membrane surrounds the lungs in the pleural cavity. It lines the pleural cavity and covers the lung. It also lines a wall of the thorax.

 

2. Pericardium

A serous membrane covers the heart and lines the mediastinum referred to as Pericardium. It lines the pericardial cavity and surrounding heart with a sac of the visceral pericardium.

 

3. Peritoneum

 

The peritoneum is the serous membrane that lines the abdominal cavity. It lines the abdominal cavity and surrounding abdominal organs. It also lines the abdominal and pelvic walls.

Function of Serous Membrane

1. Serous fluid between visceral and parietal layers enables the organ to glide freely within the cavity without being damaged by friction between it and adjacent organs.

For example,

The heart changes its shape and size during each beat and friction damage is prevented by the arrangement of the pericardium and its serous fluid.

2. Protective lubricants around organs.

3. Helps to remove harmful substances through the lymphatic system.

4. Protect the internal organs from friction and help to hold organs in place.

 5. Act as selectively permeable barriers, and prevent fluid from accumulating within the serous cavities.

3. Cutaneous Membrane/ Skin

The cutaneous membrane covers the surface of the body. It consists of keratinized stratified squamous epithelium and underlying connective tissue. Cutaneous membrane thick, waterproof and dry.

Function of Cutaneous Membrane/ Skin

1. Protection, serve to protect underlying organ and tissue in the body.

2. Forms Vitamin D

3. Protect the body's tissues and organs from mechanical and chemical trauma.

4. Acts as a barrier to water, and prevents invasion by microorganisms.

 

2. Connective Tissue Membrane

 

Connect tissue membranes Contain only connective tissue. The Main connective tissue membrane is the Synovial membrane.

Synovial Membrane

Synovial fluid is a thick liquid, rich in Hyaluronic acid. It is composed of loose connective tissue and adipose tissue covered by fibrous connective tissue (elastic fiber). No epithelial tissue is present.

The synovial membrane secretes clear, sticky, oily synovial fluid, and contain specialized cell synoviocytes which lubricate and nourishes joint so that can move freely and without friction.

Synovial membrane line cavities of moveable joints and surrounding tendons that could be injured by rubbing against bones.

 

For example,

Over wrist joint

Location of Synovial Membrane

1. Freely movable joint, shoulder, elbow, knee.

2. Other similar joints where friction needs to be reduced.

Know her what is connective tissue and the classification of connective tissue?

Function of Synovial Membrane

1. It reduced friction at movable joint

2. It nourishes cartilage covering bones at joints.

3. Lubrication

 

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