Introduction to Human Anatomy PDF

Introduction to human anatomy  Skin Superficial fascia Artery, Vein ,Nerve Deep fascia Muscles Bones joints Introduction to Skin. Fascia. - Superficial Fascia - Deep Fascia  Structure of the skin...

Introduction to human anatomy  Skin Superficial fascia Artery, Vein ,Nerve Deep fascia Muscles Bones joints Introduction to Skin. Fascia. - Superficial Fascia - Deep Fascia  Structure of the skin Dermis Epidermis  Connective tissue containing (bl. v. lymph v., sensory nerve ❑ Keratinized stratified endings, smooth m, hair squamous epithelium follicles, sweat and sebaceous devoid of blood vessels glands)  In its deep part the collagen bundles are arranged in parallel rows  Skin Layers of skin Epidermis Five type of layers Dermis Two type of layers Junction Dermal papilla Epidermal peg (rete pegs)  Skin….. Dermis Papillary layer Tactile papilla Vascular papilla Collagen fibre Reticular layer Collagen fibre Sweat glands Sebaceous glands Hairs  Skin…… Thick skin -No hairs Thin skin Devoid of Stratum lucidum  Fascia Collection of connective tissue Superficial fascia Deep fascia  Superficial fascia Superficial fascia: Loose, mixture of adipose and loose areolar tissues. It unites the skin to the underlying structures. It is dense in some places as scalp, palm of hand and sole of foot and contains collagen bundles It is thin in the eyelids, auricle, scrotum, penis and clitoris (devoid of adipose tissue). Functions: Facilitates movement of skin over underlying structures. Passage for cutaneous vessels, nerves… Protects the body against heat loss.  Superficial Fascia Site with Very less fat -Eyelids -Pinna -Penis Site with more fat - Breast - Abdomen -Gluteal region  Deep fascia It is more dense than superficial fascia Collagenous bundles are more compact and more regularly arranged It is usually present in the form of membranes  Examples of deep fascia A. Investing fascia Covers the surfaces of muscles In the neck: it forms well-defined layers, bounds fascial spaces so limits spread of infection or determine the path of infection In the abdomen: it is thin In the limbs: forms a definite sheath around the muscles  Examples of deep fascia……….. B. Inter muscular septa lie between muscles dividing the limb into compartments  Examples of deep fascia……….. C. Retinacula Localized thickening of deep fascia around joints, hold the tendons in place, prevent bowstringing of tendon  Examples of deep fascia……….. Fibrous sheath - eg. Carotid sheath Axillary sheath Fibrous capsule -eg Parotid capsule Ligaments  Absence of deep fascia Face Breast Penis Anterior abdominal wall. Blood Vessels Include arteries, arterioles, capillaries, venules, and veins. Double circuit, closed system: 1. Pulmonary circuit: Delivers blood to lungs. Oxygenation of blood. 2. Systemic circuit: Delivers oxygenated blood to tissues and organs of body (brain, liver, heart, kidneys, etc). Picks up carbon dioxide produced by tissues. Types of Blood Vessels A. Arteries and Arterioles: Carry blood away from heart to body. Have high pressure. Have thick muscular walls, which make them elastic and contractile. Vasoconstriction: Arteries contract: Reducing flow of blood into capillaries. Increasing blood pressure. Vasodilation: Arteries relax: Increasing blood flow into capillaries. Decreasing blood pressure. Types of Blood Vessels Capillaries: Only blood vessels whose walls are thin enough to permit gas exchange. Blood flows through capillaries relatively slowly, allowing sufficient time for diffusion or active transport of substances across walls. Only about 5 to 10% of capillaries have blood flowing through them. Only a few organs (brain and heart) always carry full load of blood. Blood flow to different organs is controlled by precapillary sphincters of smooth muscle. Types of Blood Vessels Veins and Venules: Collect blood from all tissues and organs and carry it back towards heart. Have low pressure and thin walls. Veins have small valves that prevent backflow of blood towards capillaries, especially when standing. If the valves cease to work properly, may result in: Varicose veins: Distended veins in thighs and legs. Hemorroids: Distended veins and inflammation of the rectal and anal areas.