Bio 123 Chapter 7- Skin and Membranes

Chapter 7- Skin and Membranes
Wednesday, February 12, 2020 12:11 PM



7.1 classification of body membranes and skin structure
Body membranes
- Thin sheets of tissue that cover!
- Cover the body
- Line body cavities
- Cover organs within the cavities
- Can be categorized into epithelial and connective tissue membrane

Purpose of membranes
- Protect and make fluids to lubricate spaces
- Cushions and reduces friction against neighboring structures

Classification of body membranes
- Epithelial membranes
○ Composed of epithelial tissue and an underlying layer of connective tissue
- Connective tissue membranes
○ Composed of various types of connective tissue

,Epithelial
- Mucous membrane: Secretes mucous
- Line body surfaces that open directly to the exterior environment
- Produce mucus, a thick secretion that keeps the membranes soft and moist
- Important for trapping unwanted particles
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- Cutaneous membrane: The skin
- Serous membranes: Line body cavities and organs
○ Secrete a thin, watery fluid
○ Lubricant helps reduce friction when organs rub against one another and cav
○ 2 layered membrane
□ Inner membrane covers organs – Visceral layer
□ Outer portion covers the body wall – Parietal layer
○ Tissue lining ventral cavity
○ 2 layered membrane
□ Inner membrane covers organs – Visceral
□ Outer portion covers the body wall – Parietal

, Dorsal cavity membranes
- Meninges

Ventral cavity
- Thoracic cavity
○ Pericardial cavity (mediastinum): Midportion of thoracic cavity; heart
○ Pleural cavities: Right lung located in right pleural cavity; left lung in left pleur
○ Lungs = pleura
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