Basic Structures I PDF

1 General anatomy Dr. Ali Sareeh Basic structures I (skin, fasciae, muscle, tendon, blood vessel, lymphatic system) 2 Level of human structure: Chemicals for...

1 General anatomy Dr. Ali Sareeh Basic structures I (skin, fasciae, muscle, tendon, blood vessel, lymphatic system) 2 Level of human structure: Chemicals form the materials of cells. Groups of cells make up tissues, which in turn make up the organs. Organs become components of systems, which together comprise the whole organism (Fig 2.1). Fig 2.1 level of human structure  Basic structures I 2 Skin The skin is the body’s largest and heaviest organ. The skin consists of 2 layers: the superficial layer is the epidermis (epi–, above, + derma, skin) the deep underlying layer is the connective tissues of the dermis (fig2.2). Fig 2.2 Skin layers keratin: a protein that toughens the skin. keratocyte keratin producing cell Melanin: is a natural skin pigment. Hair, skin, and eye color in people depends on the amount of melanin they have (fig 2.3). melanocyte melanin-producing cell Fig 2.3 epidermis *horn (Greek = keras) , black (Greek = melas)  3 General anatomy sweat pore Deep to the dermis, the loose connective tissue of the subcutaneous layer, also known as the hypodermis Hair or superficial fascia. (Not part of the skin) contain fat, nerve, and vessel.. Sebaceous gland Skin appendages sweat gland o The hair. o The nails. o The cutaneous glands (Sebaceous and sweat fig 2.5). Fig 2.4 Skin appendages The Deep Fascia (Fig. 2.5) consists of a layer of dense connective tissue immediately beneath the subcutaneous tissue. Inward extensions of this fascial layer form the intermuscular (inter-, between,+ muscle) septa. Intermuscular septum muscle Deep fascia Subcutaneous tissue (superficial fascia) Skin Fig 2.5 dissection of midcalf to show layers of skin, fascia and intermuscular septa  Basic structures I 4 Muscle Muscle is a tissue in which active contraction shortens its component cells and generates tension along their length. Latin: [musculus = little mouse] Muscle type : Smooth muscle Cardiac muscle Skeletal muscle Fig 2.5 muscle type Smooth muscle is present in the organs of the alimentary, genitourinary and respiratory systems and in the walls of blood vessels. Cardiac striated muscle is confined to the wall of the heart and is able to contract spontaneously and rhythmically. Skeletal muscle (voluntary striated muscle) is the basic component of those muscles that produce movements at joints. Structure of the muscle: A muscle cell is also known as a myocyte (myo-, muscle, + -cyte, cell) when referring to either a cardiac muscle cell (cardiomyocyte, [cardio-, heart]), or a smooth muscle cell. 5 General anatomy A skeletal muscle cell is long and threadlike is called a muscle fiber, muscle fibers are Tendon bound together into a bundle or fascicle, and group of fascicles form the entire muscle fascia Connective Tissue of the muscle: 1.The epimysium: ( epi–, on, + mys, muscle) layer of surrounding the entire skeletal muscle epimysium 2. perimysium: ( peri–, around) divide the muscle into internal perimysium compartments (fascicle) endomysium 3. endomysium: ( endo–, inside) Surrounds each skeletal muscle fiber (fig 2.6, 2.7). Fig 2.6 fascicle Skeletal muscle structure Muscle fiber Fig 2.7 Cross section of Skeletal muscle  Basic structures I 6 Tendons At each end of the muscle, the collagen fibers of the epimysium, perimysium, and endomysium tendon come together and form a tendon that attaches Fibrous sheath the muscle to bone, cartilage, or skin (fig 2.8). Fig 2.8 dissection of the left hand Blood vessels Blood circulates throughout the body in the cardiovascular system, which consists of the heart and the blood vessels. Three types of blood vessels  Arteries are thick-walled that carry blood away from the heart. Some arteries are named after the region through which they pass (femoral artery), while others according to the structures they supply (renal artery).  Capillaries, the smallest vessels, link the smallest arteries (arterioles) and the smallest veins (venules). In capillaries exchanges take place between the blood and the tissues.  Veins accompanying arteries.many veins contain unidirectional valves, which direct the flow of blood towards the heart (2.9). valve Fig 2.9 Types of the blood vessels  7 General anatomy artery Vein nerve Deep vein Superficial vein Fig 2.10 dissection through the right leg showing the blood vessels. In general, there are few alternative pathways for arterial blood to reach its destination. However, in some regions (e.g. joints and at the base of the brain), arterial supply is provided by more than one vessel (Fig. 1.11). Such arteries may communicate directly with each other at sites known as arterial anastomoses. The venous pattern is often variable, and numerous anastomotic connections provide alternative pathways for venous return Fig 2.11 Dorsal carpal anastomosis  Basic structures I 8 Lymphatic system Tissue fluid is collected by open-ended channels called lymphatics vessel (fig 2.12). From a particular region or organ, these lymphatic vessels drain into aggregations of lymphoid tissue (called lymph nodes Fig. 2.13), which filter lymph. Ultimately, lymph drains into the venous system. Tissue fluid Capillary Vein Artery Lymph capillary Lymphatic Fig 2.12 Lymphatic vessel vessel Lymph node Lymph node Lymphatic vessel Lymph node Fig 2.13 a part of the Lymphatic system