Anatomy and Physiology / Unit 2: Cells and Tissues
2.6 Membranes and Tissue Repair
Notes
Body membranes are sheets of tissue that cover or line.
- Cutaneous membrane: the skin. Mucous membranes line openings to the outside (digestive, respiratory, urinary and reproductive tracts) and secrete mucus. Serous membranes line closed ventral cavities and secrete watery fluid (pleura, pericardium, peritoneum). Synovial membranes line joint cavities and make lubricating fluid.
- Tissue repair has two modes. Regeneration replaces damaged cells with the same type. Fibrosis replaces them with scar tissue (dense collagen), which is not functional like the original.
- Steps: inflammation (clot and swelling), then organization (granulation tissue and new capillaries), then regeneration and fibrosis.
- Example: epithelium of the skin regenerates well; cardiac muscle after a heart attack mostly heals by fibrosis.
Practice
Which membrane type lines the digestive tract and secretes mucus?
Mucous membranes line body tracts that open to the outside.
After a heart attack, dead cardiac muscle is replaced mostly by scar tissue. This is an example of:
Cardiac muscle has little ability to regenerate, so dense connective scar tissue fills the area.
The pericardium, which surrounds the heart and secretes a slippery fluid, is a:
Serous membranes line closed body cavities and cover organs, reducing friction.
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