Body Membranes Learning Outcome A3

A3 – Body Membrane Student Achievement Indicators: Describe the three major categories of body membranes

Epithelial Membrane Made up of epithelial sheets and an underlying layer of connective tissue.

Introduction to Membranes Are thin sheets of tissue that covers surfaces, line body cavities and surround organs. Classified as either epithelial or connective tissue. Epithelial membranes include the cutaneous membrane (skin), mucous membranes and serous membranes. Connective tissue membranes include the synovial, periosteum, perichondrium, meninges and fascia

Cutaneous Membrane AKA skin Outer layer is known as the epidermis and is composed of stratified squamous epitheilium. This is the layer that protects the body from invading organisms. Also prevents the body from drying out or dehydrating, because squamous cells contain a waterproof substance.

Cutaneous Membrane

Mucous Membranes Lines all the body cavities that open to the exterior of the body. Contains stratified squamous epithelium or simple columnar epithelium. Adapted for absorption and secretion. Most secrete mucous; which keeps the membrane moist and lubricated. Example – food moving through the digestive system.

Mucous Membrane

Serous Membrane Line ventral cavities that do not open to the exterior of the body. Secrete a thin, watery fluid known as serous fluid. Serous fluid allows membranes to slide past one another. Composed of a single layer of simple squamous epithelium, resting on a layer of connective tissue. Line body cavities and fold back and cover organs.

Serous Membrane of the Liver

Serous Membrane of the Thoracic Cavity

Layers of the Serous Membrane Parietal layer – is the part of the serous membrane that lines the wall of the cavity. Visceral layer – is the part of the serous membrane that covers the outside of organs.

Types of Serous Membranes Pleura – is found in the thoracic cavity The parietal pleura lines the walls of the thoracic cavity. The visceral pleura covers each lung. Pericardium – is found in the thoracic cavity and is associated with the heart. The parietal pericardium lines the sling (pericardium) that supports the heart. The visceral pericardium forms the outside of the heart.

Types of Serous Membranes Peritoneum – is found within the abdominal cavity. The parietal peritoneum lines the walls of the abdominal cavity. The visceral peritoneum lines the organis present in the abdominal cavity.

Infections of the Abdominal Cavity Appendicitis – is a ruptured appendix, which releases bacteria in the peritoneal cavity. This causes peritonitis, which can be treated by antibiotics. Pleurisy – refers to the inflammation of the pleura and a decrease in serous fluid. This means the membrane rubs together, creating pain during breathing.

Connective Tissue Membrane Lines joint cavities

Synovial Membrane Is the membrane found between joints. Prevents bones and cartilages from rubbing together. Prevents friction

Synovial Membrane

Periosteum Periosteum is a membrane the lines the outer surface of all bones., except at the joints.

Periosteum

Perichondrium Perichondrium - is a layer of dense irregular connective tissue which surrounds the cartilage of developing bones.

Perichondrium

Meninges Membranes that envelope the central nervous system.

Fascia Fascia is a connective tissue that surrounds muscles, group of muscles, blood vessels, and nerves, binding those structures together.