Blood and Vascular Ph Therapy PDF WORD.pdf

VASCULAR SYSTEM By Dr. Esam Elshwihy BLOOD Blood cells (45% of the total blood volume) Red blood cells (corpuscles) or erythrocytes White blood cells or leukocytes Platelets or thrombocytes. ERYTHROCYTES (Red blood cell...

VASCULAR SYSTEM By Dr. Esam Elshwihy BLOOD Blood cells (45% of the total blood volume) Red blood cells (corpuscles) or erythrocytes White blood cells or leukocytes Platelets or thrombocytes. ERYTHROCYTES (Red blood cells, RBCs) Shape: They are rounded biconcave discs. Size: The normal diameter of RBCs varies between 6 - 9 microns (7.5 m average) these cells are normocytes. RBCs larger than 9 m in diameter are called macrocytes as in macrocytic anaemia. Those smaller than 6 m in diameter are called microcytes as in microcytic anaemia. Number: 4.5-5.5 millions/mm3 of blood. Structure: They are not true cells, as they have no nuclei, or organoids. The cytoplasm contains mainly Hb (cell inclusion) enclosed by cell membrane. They have biconcave disc shape Reticulocytes: These are immature erythrocytes which constitutes normally about 1% of the circulating erythrocytes. Their diameter is slightly larger than mature erythrocyte. The reticulocytes have no nuclei, but they contain some free ribosomes and few mitochondria. LEUKOCYTES (White Blood Cells, WBCs) Total leukocytic count: the normal total number of leukocytes is 4,000 – 11,000/mm3 of blood. Differential leukocytic count is the percentage of each type of leukocytes to the total number of leukocytes. I) Granular leukocytes: 1- Neutrophils 50-70 % 2- Eosinophils 1-4 % 3- Basophils 0-0.5 % II) Nongranular leukocytes: 1- Lymphocyles 20-40% 2- Monocytes 2-8 % NEUTROPHILS (Polymorphs, Polymorphonuclear leukocytes) Nucleus: The mature cell has one segmented (lobulated) nucleus formed of 2-5 lobes (usually 3 lobes) Cytoplasm: It contains two types of granules: A- Specific granules, which are small and more numerous (80%). B- Non-specific (azurophilic) granules, which are larger and less numerous (20%). They are lysosomes. Functions Antibacterial. It is the most important in acute inflammation. EOSINOPHILS: a- The nucleus is bilobed with horse-shoe shaped appearance. b-The cytoplasm contains two types of granules: 1- Specific eosinophilic granules. By electron microscope these granules show central crystalline dense core and contain antiparasitic and histaminase. 2- Non-specific granules which are lysosomes containing hydrolytic enzymes. Functions: 1. Antiallergic. 2. Antiparasitic. BASOPHILS a- The nucleus is S-shaped. b-The cytoplasm contains two types of granules: A- Specific granules which obscure the nucleus. They are similar to those of mast cells containing heparin and histamine. B- Non-specific granules which are lysosomes containing hydrolytic enzymes. Functions: Secretion of heparin---------anticoagulant. Secretion of histamine-------causes allergy. LYMPHOCYTES 1) Small lymphocytes a) The nucleus is relatively large and rounded. Its chromatin is so condensed. b) The cytoplasm is scanty and has few organelles. 2) Large lymphocytes a) The nucleus is relatively large and rounded with indentation at one side. Its chromatin is less condensed than that of the small lymphocytes. b) The cytoplasm is basophilic because it contains an increased amount of free ribosomes. Functions: Humoral immunity by B-lymphocytes. Cellular immunity by T-lymphocytes. MONOCYTES a) The nucleus is oval or kidney shaped and is eccentrically placed. b) The cytoplasm contains lysosomes. Functions: Phagocytosis. Production of mono-nuclear phagocytic system. BLOOD PLATELETS (Thrombocytes) By L/M: It has a peripheral pale hyalomere and a central granular granulomere. By EM: The hyalomere contains: Microtubules which act as internal skeleton that maintains the oval shape.  Actin and myosin filaments (help in platelet movement and aggregation). The granulomere contains: Dense granules : – Alpha granules contain fibrinogen. – Delta granules contain ADP, ATP, epinephrine and serotonin. – Lambda granules which are lysosomes. BLOOD VESSELS The cardiovascular system is composed of: 1. The heart. 2. Blood vessels. a) The arteries that carry the blood from the heart to tissues. b) The veins that carry the blood from tissues to the heart. c) Arterio-venous connections in the form of capillaries. General structure of blood vessels 1-Tunica intima: (The innermost). It consists of: a) Endothelium: (simple squamous cells). b) Subendothelium: loose connective tissue. 2-Tunica media: (The middle layer). It is formed of: c) Circular smooth muscle cells. d) Variable amounts of elastic fibers. 3-Tunica adventitia: (The outermost layer). It consists of loose connective tissue. It contains small blood vessels (vasa vasorum) that supply the outer part of the wall while the inner part is supplied from the blood in its lumen. II- ARTERIES They are: 1- Large (elastic) arteries 2- Medium sized (muscular) arteries 3- Arterioles 4- Metarterioles LARGE (ELASTIC) ARTERIES: They are the aorta and its main branches. The specific features: Tunica media: the main component of the wall of the aorta. - It consists mainly of concentric layers of elastic laminae. - Between the elastic laminae, there arecircular smooth muscle c) Tunica adventitia: It is relatively thin. Large veins (e.g. inferior vena cava): The specific features: b) Media: It is thin with few layers of smooth muscle cells. c) Adventitia: It is the thickest layer and contains bundles of longitudinally arranged smooth muscle. Valves are present. CAPILLARIES - Capillaries are the smallest and thinnest channels in the circulatory system. - Capillaries arise from metarterioles or directly from arterioles. - They recollect forming venules. Structure: L/M: The blood capillary consists of: Endothelial cells: The cross section usually contains a single layer of 1-3 endothelial cells. Basal lamina. Pericytes: - They partly surround the endothelial cells with their long cytoplasmic processes. - They contain actin and myosin and may have a contractile function. - Following tissue injuries pericytes produce smooth muscle cells of the newly formed blood vessels. Types of blood capillaries 1) Continuous capillary - The endothelial cells have no fenestrae (pores) - - It is present in brain. 2) Fenestrated capillary The endothelial cells have large fenestrae in their walls. It is present in the renal glomeruli and endocrine glands. The basal lamina is continuous. 3) Sinusoidal capillary It has a tortuous path and wide. The endothelial cells have multiple fenestrae. The basal lamina is discontinuous. They are present in the liver, bone marrow and spleen.