Overview
This lecture covers the structure, types, and functions of membranes in the body, focusing on their composition and role in protection, secretion, and movement.
Membrane Structure and Composition
- Membranes are thin sheets of tissue, usually made of epithelial tissue with or without connective tissue.
- Some membranes may contain smooth muscle in addition to epithelial and connective tissues.
Functions of Membranes
- Membranes line surface cavities and act as barriers.
- They protect the body, contribute to immunity, and produce secretions.
- Membranes anchor organs in place and reduce friction to allow for movement and growth.
Types of Membranes
- True membranes include serous membranes (pleura, peritoneum) and synovial membranes (joint linings).
- Membrane-like structures include mucous membranes (lining body openings) and the cutaneous membrane (skin).
Mucous Membranes
- Mucous membranes line all openings to the body and consist of epithelial layers with a basement membrane, sometimes containing smooth muscle.
- They maintain cell moisture, trap pathogens, and contain local antibodies to prevent infection.
- Mucous membranes help lubricate passageways, aiding in the movement of substances like food.
Clinical Relevance: Membrane Inflammation
- Inflammation of serous membranes (pleura or pericardium) can cause friction rubs, leading to pain and audible rubbing sounds during breathing.
- These conditions may be inflammatory or infectious and can often be resolved with treatment.
Key Terms & Definitions
- Membrane — Thin tissue sheet that lines surfaces or cavities in the body.
- Epithelial Tissue — Tissue forming the outer layer of body surfaces and lining cavities.
- Connective Tissue — Tissue supporting, binding, or separating other body tissues.
- Serous Membrane — True membrane lining internal body cavities (pleura, peritoneum).
- Synovial Membrane — True membrane lining joint cavities.
- Mucous Membrane — Membrane-like structure lining body openings, secreting mucus.
- Cutaneous Membrane — The skin, covering the body surface.
- Friction Rub — Audible sound and pain caused by inflamed membranes sticking together.
Action Items / Next Steps
- Review assigned anatomy slides.
- Prepare for the next lecture on connective tissues.
- Contact the instructor if you have questions.