(Systems of the body 1 )

🚨 محاضرة ملغية 🚨

🟠 Structure of Skin
Epidermis: Outermost, avascular.
Dermis: Deep, vascular, contains CT, glands, hair follicles.
Subcutaneous tissue (Hypodermis): Mostly fat, connects skin to deeper structures.
🟣 Skin Appendages
Hairs: All body except palms & soles.
Root (under skin), Shaft (above skin).
Nails: Hard plates.
Root, body (visible), nail bed.
Sebaceous glands: In dermis (face, scalp), secrete sebum. ❌ Absent in palms & soles.
Sweat glands: Coiled, control body temp. ❌ Absent in lips & nail beds.
📌 Fascia
Superficial fascia: Loose + fatty CT, connects skin → deep fascia, insulation.
Deep fascia: Tough membrane around muscles.
Intermuscular septa: separate muscle groups.
Retinacula: hold tendons (wrist/ankle).
Aponeurosis: sheet-like tendon (palm, sole).
🚨 Clinical Importance
Site for injection & absorption (subcutaneous layer).
Sweat gland function crucial for thermoregulation.
Sebaceous gland blockage → acne.