HEM-210 Faculty of Medicine – Sohag University PDF

HEM-210 Page 1 Faculty Of Medicine – Sohag University  HEM-210 - Title Page 1 Anatomy 3 2 Histology 13 3 Biochemistry 43...

HEM-210 Page 1 Faculty Of Medicine – Sohag University  HEM-210 - Title Page 1 Anatomy 3 2 Histology 13 3 Biochemistry 43 4 Physiology 58 5 Microbiology 92 6 Parasitology 109 7 Pathology 137 8 pharmacology 165 Page 3 Faculty Of Medicine – Sohag University  HEM-210 Page 3 Faculty Of Medicine – Sohag University  HEM-210 1 The lymphatic system Lymphatic system it is the overflow system that provides drainage of tissue fluids and leaked plasma proteins to the blood stream as well as removal of debris from cellular decomposition and infection (figure 1). It is formed of: 1-Lymph vessels, 2- lymph nodes, 3- lymphoid organs that produce lymphocytes (tonsils, spleen, thymus gland, red bone marrow and lymphoid follicles at wall of intestine and appendix). Figure 1: lymphatic system and its componenets (nodes and vessles) Page 4 Faculty Of Medicine – Sohag University  HEM-210 Lymph it is colorless fluid which circulates between cells and tissues to remove dead cells, waste products and toxins. That It runs inside thin walled vessels called the lymphatics, which accompany the veins but not seen by naked eyes. In small intestine, fats are absorbed by intestinal epithelium and packed to form milky opaque lymph which is called chylomicrons; here the lymph is termed chyle. Lymphatic vessels (Lymphatics): 1- Extensive and complex interconnected network channels. 2- It is distributed all over the body (figure 1). 3- Thin-walled and have abundant lymphatic valves, so the beaded appearance. 4- It collect fluid from capillary beds during nutrients exchange processes and deliver it back to the venous side of the vascular system 5- It begins as lymphatic capillaries (figure 2) Figure 2: Lymphatic capillary (fine structure) 6- Lymphatic capillaries in turn drained by small lymph vessels which unite to form large lymph vessels which connected with large veins in the root of the neck. 7- It present in the most areas in the body except brain, bone marrow, epidermis, eyeball and cartilage. Page 5 Faculty Of Medicine – Sohag University  HEM-210 8- Lymphatic vessels that carry lymph to a lymph node are referred to as afferent vessels; those that transport it away from a node are efferent vessels (figure 3). Figure 3: Cut section in lymph node N.B Movement of lymph is controlled by the action of adjacent muscle especially the skeletal muscles and pulse of arteries. Unidirectional flow maintained by the presence of valves in the lymphatics. Lymph nodes: These are several small masses of lymphoid tissue present at the pathway of lymphatic vessels, small and encapsulated (0.1 to 2.5 cm long). It contains elements of body defense systems like lymphocytes and macrophages. It presents in certain groups which may be superficial to skin at areas and deep in other areas (figure 4). Page 6 Faculty Of Medicine – Sohag University  HEM-210 1- Axillary lymph nodes which drain upper limb and breast 2- Cervical lymph nodes which drain head and neck 3- Mediastinal lymph nodes which drain thoracic organs 4- Aortic lymph nodes which drain abdominal organs 5- Inguinal lymph nodes which drain groin and lower limbs. Figure 4: Groups of lymph nodes N.B Because lymph nodes are efficient filter and flow through it is slow, cells that metastasize or migrate from primary tumor and enter the lymphatic vessels are often lodged in and stagnate at it. So, lymph nodes are considered as secondary tumor; here it becomes palpable and enlarged. Also, Infection or inflammation could enlarge it (figure 5). Page 7 Faculty Of Medicine – Sohag University  HEM-210 Figure 5: Enlarged lymph node Lymphatic trunks and ducts: 1- All lymphatic vessels coalesce together to form larger trunks and ducts. 2- Trunks and ducts are drained into venous system at sides of the neck where the internal jagular veins join the subclavian veins to form the brachiocephalic veins. 3- Lymph from the right side of head and neck, right upper limb, right side of the thorax and right upper abdominal wall is drained to right lymphatic duct (figure 6). Figure 6: Showing right and left lymphatic ducts and its drainge site 4- Lymph from the left side of the body is drained to the thoracic duct (figure 6). Page 8 Faculty Of Medicine – Sohag University  HEM-210 Thoracic duct: 1- It is the largest lymphatic duct in the body 2- It drains lymph from the lower limbs, pelvis, perineum, abdomen, left side of the neck and left upper limb. 3- Length = 45 cm. 4- Course: it takes origin from the upper end of the abdominal lymph trunks or cisterna chyli in front of the lower border of the last thoracic vertebra ( figure 7); it reaches the thorax by ascending through the aortic opening of the diaphragm between thoracic aorta and azygos vein. It ascends at the posterior the mediastinum in front the anterior longitudinal ligament of the vertebral column and in front of right aortic posterior intercostal arteries and terminal part of hemiazygos vein. Later on, it crosses gradually from right to left side of the median plane of the body in front the fifth thoracic vertebra. It continues upward behind the esophagus at the superior mediastinum. Later on, it Figure 7: Showing course of thoracic duct becomes at the left side of the esophagus with the aortic arch. At level of the seventh cervical vertebra, its 5- At termination site, thoracic duct cervical part curves behind the carotid contains two competent valves sheath to terminate in the angle of to prevent reflux of venous blood junction between left internal jagular and to it. left subclavian vein where it is drained to venous system (figure 7). Page 9 Faculty Of Medicine – Sohag University  HEM-210 Lymphoid organs: Parts of body that produce lymphocytes such as: 1- Thymus gland 2- Tonsils 3- Spleen 4- Red bone marrow 5- Lymphoid follicles at wall of alimentary tract and appendix.. 1-Thymus gland: It is a central lymphoid organ which involved in early development of the immune system, it is well developed at birth and grows until puberty, and later on it is diminished at size nd replaced by fibrous and adipose tissue. It has unequal 2 pyramidal lobes which are bound together by loose connective tissue (figure 8). Figure 7: Thymus gland Position: it presents at the most anterior part of superior mediastinum, immediately posterior to manubrium of the sternum; its upper part extends to the neck, its lower part extends in the anterior mediastinum over the pericardial sac, it overlaps the great vessels of the heart (figure 8). Page 10 Faculty Of Medicine – Sohag University  HEM-210 2-Tonsils: Collection of lymphoid tissue at the mucosa of pharynx surrounding the openings of nasal and oral cavities forming distinct masses called tonsils. 1-Pharyngeal tonsils: it lies at midline on the roof of the nasopharynx (figure 9), when it is enlarged it is called (adenoid). Figure 8: Sagittal section showing sites of tonsils 2-Palatine tonsils: it lies at the side of the oropharynx between palatoglossal and palatopharyngeal aches just posterior to oropharyngeal isthmus. 3-lingual tonsils: it presents at the posterior part of the tongue. 3-Spleen: It is considered as the largest lymphoid organ in the body, it is reddish brown in colour. Position: it lies in the left hypochondrium between stomach and diaphragm under the 9th, 10th and 11th ribs, its weight is about 200gm. Shape: pyramidal and has 2 ends: medial and lateral; with 2 borders; upper and lower. It has 2 surfaces; diaphragmatic (related to the diaphragm which separate it from ribs) and visceral (related to stomach, left kidney and left colic flexure) (figure 10). Page 11 Faculty Of Medicine – Sohag University  HEM-210 Figure 9: Spleen Functions of the spleen: Formation of some blood cells Storage of blood cells Formation of antibodies Formation of bile pigments Removal of toxins, dead cells and bacteria from blood. N.B Reticulo endothelial system: it includes spleen, lymph nodes, tonsils, blood leucocytes and other phagocytic cells scattered in liver, lungs, and endothelium of blood vessels for protection against bacteria, toxins and foreign bodies. Page 12 Faculty Of Medicine – Sohag University  Hematology HEM-210 Page 11 Faculty Of Medicine – Sohag University  HEM-210 Hematology Block HEM-210 ‫إعداد و تأليف‬ ‫قسم الهستولوجيا‬ 2023-2024 Page 14 Faculty Of Medicine – Sohag University  ‫‪HEM-210‬‬ ‫الرؤية والرسالة‪:‬‬ ‫‪1-4‬الرؤية‪:‬‬ ‫تسعي كلية الطب بجامعة سوهاج أن تكون مركزا للريادة والتفوق والتميز في مجال‬ ‫العلوم الطبية علي الصعيدين اإلقليمي والعالمي‬ ‫‪2-4‬الرسالة‪:‬‬ ‫تلتزم كلية الطب البشرى بجامعة سوهاج بتقديم برامج طبية متميزة وتبني آليات‬ ‫التعليم الطبي المستمر وإجراء بحوث علمية متميزة وخدمات مجتمعية بما يضمن‬ ‫تطوير المهنة وتخريج أطباء قادرين على تلبية احتياجات سوق العمل وتنمية المجتمع‬ ‫المحلى واالقليمي والدولي فى ضوء المعايير األكاديمية القومية وقيم المجتمع النبيلة‪.‬‬ ‫‪Page 15‬‬ ‫‪Faculty Of Medicine – Sohag University‬‬  HEM-210 1 THE LYMPHTIC SYSTEM Learning objectives: A1- Describe the cytological A2- Define & classify lymphatic characteristics of lymphocytes tissue; diffuse and nodular A3- Describe the structure of lymphatic organs. Lymphocytes (Fig.1): Accounting for 20-35%, of the circulating W.B.Cs. Structure: L.M. E.M. deep stained nucleus small Golgi thin rim of clear blue cytoplasm a pair of centrioles no specific granules but contain few Many free ribosomes but no small azurophilic granules endoplasmic reticulum one or two mitochondria Types of lymphocytes: - On the basis of cell diameter, they are divided into small (4-7 um), medium sized (7-11 um) Large lymphocytes (11-15 um). Page 16 Faculty Of Medicine – Sohag University  HEM-210 - According to the presence of distinct surface markers determined by immunohistochemical methods small lymphocytes are divided into ; B lymphocytes, T lymphocytes Null cells. Fig. ( 1): L.M & EM of lymphocyte B lymphocytes: 1-Origin: in mammals they arise from the stem cells in the bone marrow. 2-Life span: B lymphocytes have a short life span (few weeks) and during this time they circulate and recirculate through the blood, lymph nodes, spleen and lymph for many times. 3-Activation: B lymphocytes when activated, they differentiate into large lymphocytes then to lymphoblasts to plasma cells that produce immunoglobulins. Some of activated lymphocytes remain as B memory cells. This type is called humeral response. Page 17 Faculty Of Medicine – Sohag University  HEM-210 T lymphocytes: 1-Origin: Stem cells originate in the bone marrow that is carried through the blood to the thymus where they proliferate and differentiate to T lymphocytes. At the cortico-medullary region they become mature T lymphocytes, then they leave the thymus through post capillary venules to the spleen then to the circulating pool of lymphocytes. 2-Life span: T lymphocytes have a long life span for several months. - T lymphocytes have a long life span for several months. 3-Activation: - T lymphocytes when activated by antigen, they soon differentiate into four types of cells producing cellular immune response. These cells are: T killer or rejection cells: Those reject transplanted organs or skin grafts. T memory cells: They are programmed to react with the same antigen on entering the body for another time. T helper cells: They help B lymphocytes producing humoral immunity. T suppressor cells: They inhibit the activity of both B and T lymphocytes triggering the end of the immune response. Page 18 Faculty Of Medicine – Sohag University  HEM-210 THE LYMPHOID TISSUE - Lymphatic tissue is defined as reticular connective tissue that is infiltrated with lymphocytes. - This includes discrete organs as well as more diffuse aggregations of lymphocytes. The lymphoid organs are either primary or secondary. Primary organs Secondary organs where lymphocytes are formed where lymphocytes are activated and mature as bone marrow and as lymph nodes, spleen and thymus. mucosa associated lymphoid tissue (MALT). MALT is numerous scattered non-capsulated lymphoid nodules distributed in the mucosa of the digestive, respiratory and urinary systems collectively. The lymphoid nod :ule - It is a spherical mass of lymphocytes. Page 19 Faculty Of Medicine – Sohag University  HEM-210 Sites of the nodule: 1- Lymphatic organ as spleen, lymph node and tonsil. 2- In lamina propria of digestive and respiratory system. 3- Payer’s patch of ilium 4- appendix Types of the nodule A.Primary lymphoid nodules : They represent the unstimulated follicles. They are formed of closely packed small lymphocytes. B. Secondary lymphoid nodules : - When the primary nodules are stimulated by antigen (any foreign protein), they become secondary nodule. - This secondary nodule consists of two zones. The outer zone (mantle), also called peripheral zone contains small lymphocytes with less cytoplasm so it stains dense. The inner zone, also called germinal center or central zone contains large and medium lymphocytes, lymphoblast, plasma cells and macrophages. It stains pale due to these cells have more cytoplasm and euchromatic nuclei. 1- THYMUS - The thymus is a primary lymphoid organ situated in the superior mediastinum. Page 20 Faculty Of Medicine – Sohag University  HEM-210 Lymphoblast differentiates into T-lymphocytes within the special microenvironment of the thymus, independent of antigenic stimulation. After differentiation, the thymus populates T-lymphocytes to the peripheral lymphoid organs. The thymus is well developed at birth and during early childhood, then it begins to involute. - Histological Organization (Fig. 2): The thymus is composed of stroma and parenchyma. - The Stroma: is formed of Thin capsule. Trabeculae of loose C.T divide the gland into incomplete lobules. Supporting network of epithelial reticular cells. - The parenchyma: is formed of thymic lobules. Each lobule has a dark-staining peripheral zone, the cortex and a lighter-staining inner zone, the medulla. At the cortex, the lymphocytes (thymocytes) are numerous and densely packed, causing the intense basophilia of this region. At the medulla, the lymphocytes are fewer and the epithelial reticular cells with their abundant eosinophilic cytoplasm are more prominent. Page 21 Faculty Of Medicine – Sohag University  HEM-210 - Thymocytes: Represent the main cellular population of the thymus. These include small, medium and large lymphocytes. Epithelial Reticular Cells or cytoreticular cells: These are branched cells form a network that carry lymphocytes and is referred to as cytoreticulum. The cells have several processes that joined together by desmosomes. According to E.M. structure, location and histochemical characters they are of 6-types. - Hassall's corpuscles (Fig. 3) : They are acidophilic with hyalinized centers. It is formed by type 6 reticular cells in the medulla. These cells are flattened and tend to wrap around one another and joined together by many desmosomes and contain abundant bundles of keratin filaments. The cells in the central portion of the corpuscle lose their nuclei and cytoplasm is full of keratin. Fig.(2) A diagram showing the histological structure of thymus Page 22 Faculty Of Medicine – Sohag University  HEM-210 Fig (3): A diagram showing the cortex and medulla of the thymic lobule - The blood-thymus barrier (Fig. 4) It prevents antigenic macromolecules of the blood from reaching the thymus. Page 23 Fig (4): A diagram showing the blood thymic barrier Faculty Of Medicine – Sohag University  HEM-210 2- LYMPH NODES - There are 500-600 lymph nodes (lymph glands) in the body. A lymph node is capsulated round, ovoid, or bean-shaped and varies in size from less than 1 mm to 2-3 cm. Structure (Fig. 5) The lymph node is formed of stroma and parenchyma. - The stroma : C.T. capsule that greatly thickened at the hilum. Branching trabeculae extend from the deep surface of the capsule inwards to divide the organ into relatively regular compartments in the outer part (cortex) and more irregular compartments in the inner part (medulla) of the gland. Between the trabeculae, the lymphoid tissue is supported by a network of reticular fibers and reticular cells. - The parenchyma 1) The cortex It is formed of three zones; outer, mid and deep cortical region. The lymphoid nodules are of primary and secondary types. They form the great bulk of the outer cortex while the diffuse lymphoid tissue makes up the bulk of the mid and deep cortex. B-lymphocytes are the predominant cells in the outer cortex while T- lymphocytes are the predominant cells in the mid and deep cortical zones. The mid and deep zones are called thymus dependent zones of the lymph nodes. Page 24 Faculty Of Medicine – Sohag University  HEM-210 They contain an antigen presenting cells known as dendretic cells. 2) Medulla 1. The medullary cords consist of aggregations of lymphoid tissue organized around small blood vessels. They are formed of small lymphocytes, plasma cells and macrophages. 2. The lymph sinuses are channels lined with a layer of thin squamous cells without basal lamina and supported by a thin layer of reticular C.T. 3. All the sinuses contain macrophages which remove particulate matter and degenerating cells from the lymph and filter it from bacteria or malignant cells. 3-THE SPLEEN - The spleen is a large lymphoid organ present in the left upper quadrant of the abdominal cavity. Histological Organization of the Spleen: The spleen is formed of stroma and parenchyma. - The stroma: It is formed of Capsule Thick trabeculae N.B. Delicate reticular fibers framework that Both the capsule and the occupies the interior of the organ and holds trabeculae consist of dense C.T. rich in elastic in its meshes the free cells of the fibers. In human, they contain few smooth parenchyma. muscle cells Page 25 Faculty Of Medicine – Sohag University  HEM-210 - The Parenchyma (Fig.6) : A-The white pulp: 1. The periarterial lymphoid sheaths (PALS): 2. It consists of a central artery (a branch of the splenic artery) that surrounded by a sheath of lymphoid tissue 3. Malpigian corpuscle (lymphoid follicle): 4. the central artery is located at the periphery of nodule. B-The marginal zone : 1. It is the transitional zone between the white pulp and the red pulp of the spleen. C-Red pulp : 1. Pulp cords (cords of Billroth) are consist of large number of RBCs, macrophages, lymphocytes dendritic cells, plasma cells and granulocytes. 2. The splenic venous sinuses. Fig. (6): A diagram showing the structure of the spleen Page 26 Faculty Of Medicine – Sohag University  HEM-210 2 THE BLOOD A1- Describe the cytological characteristics of blood elements A2-Define & classify A3- Describe formation bone marrow types of blood elements - Blood is considered as a special type of C.T composed of: Formed elements: erythrocytes, leucocytes and blood platelets, suspended in an extracellular fluid matrix (the blood plasma). RED BLOOD CORPUSCLES (RBCs), (ERYTHROCYTES) At L.M. level: They appear acidophilic non-nucleated cells (not true cells so called corpuscles) and have biconcave shape to increase surface area (Fig. 1) seen as central pallor of staining. The erythrocytes form aggregates that resemble stacks of coins called rouleaux. This happens only in stagnant blood in vitro Abnormalities in the shape of RBCs e.g. sickle cell anemia (Fig. 2). Fig. (1): Scanning electron microograph of Fig. (2): Scanning electron micrograph of an erythrocytes showing their Biconcave shape. erythrocyte in sickle cell anaemia. Page 27 Faculty Of Medicine – Sohag University  HEM-210 Ultrastructure of Erythrocy tes Cell organelles are lacking. Hb molecules form dense homogenous content of a granular texture. Immediately beneath the membrane, there is a network of membrane cytoskeleton: which makes R.B.Cs. to be quite pliable when flowing through narrow capillaries. Characters of RBCs: - Size: Normal R.B.Cs varies from 6-9 um in diameters and about 1.9 um in thickness. These are called normocytes. - Color: The normal color of R-B.Cs is greenish or orange yellow. When they condense, the color is red. The normal color of R.B.Cs is called normochromic. The decrease in amount of Hb content resulted in hypochromic R.B.Cs occurs in iron deficiency anemia. The increase in the amount of Hb result in hyperchromic R.B.Cs. WHITE BLOOD CELLS (W.B.Cs) (LEUKOCYTES) Differences between WBCs and RBCs Leucocytes are colorless do not contain pigment they contain granules. Leucocytes are capable of amoeboid movement. They perform their function in the C.T. They are larger in diameter. Page 28 Faculty Of Medicine – Sohag University  HEM-210 Number The total leukocyte count in the circulation ranges from 5000 to 9000/cu mm. Classification of Leucocytes Leucocytes are classified as granular and non-granular depending on weather they do or do not contain specific granules in their cytoplasm. note: Both types contain non-specific granules in their cytoplasm(Azurophilic non-specific granules are primary lysosomes) 1 -Granular leucocytes are; neutrophils, eosinophils and basophils 2 -Non-granular leucocytes include lymphocytes and monocytes N.B Neutrophils constitute 60-70% The relative number of eosinophils 2-5% each type of leucocyte is basophils 0-1% called the differential lymphocytes 20-35% leucocytic count. Monocytes 3-7%. Clinical notes: An increase in the number of leucocytes is called leukocytosis while its decrease is called leucopenia. Neutrophil Leucocytes: Diameter of granular leukocytes about 10-12 um. They are called polymorphs, polymorpho-nuclear leucocytes or tissue microphages. Page 29 Faculty Of Medicine – Sohag University  HEM-210 they increase in acute pyogenic infection for defence against invasion of bacteria by phagocytosis and. - By L.M 1. The nucleus: multilobed (more than 2lobes connected by chromatin thread). 2. The cytoplasm is stippled with very fine specific granules stain faintly pink. - By E.M. (Fig.3) The cytoplasmic granules of neutrophils are of two main types : 1. Azurophilic primary non-specific granules or lysosomes are large, dense vesicle 2. Specific secondary granules are smaller and less dense , Fig. (3): micrograph of neutrophil LM, E.M. Eosinophil Leucocytes: By L.M : The nucleus is bilobed. The cytoplasm contains large eosinophilic refractile granules. By E.M. (Fig. 4): Page 30 Faculty Of Medicine – Sohag University  HEM-210 The specific granules contain dense crystalloid core included in amorphous matrix. The granules contain major basic proteins which control parasites and control allergy. In chronic inflammation: Eosinophils are particularly abundant in connective tissue of the intestinal lining and at sites of chronic inflammation Fig. (4): eosinophil by LM, E.M Basophil Leucocytes: - By L.M. The nucleus is U or S shape. The specific granules are relatively few, large and basophilic Which may obscure the nucleus. - By E.M(Fig.5).: The cytoplasm contains; The specific granules are large dense rounded and they contain histamine and heparin like mast cells. On degranulation release of basophilic mediators(histamine) from specific granules causing allergic reaction or anaphylactic shock. Page 31 Faculty Of Medicine – Sohag University  HEM-210 U shape nucleus Fig. (5): basophil by LM, E.M Lymphocytes - Previously discussed in lymphatic system- see fig Monocytes - Measure about 12-20 um. in diameter in stained blood film (largest cell in blood film). - BY L.M. The nucleus is eccentric kidney shapes. The cytoplasm is pale blue contains few azurophilic granules. - BY E.M. Fig:)7(. Function: 1- capable of developing into macrophage after they migrate into the C.T. 2- They also act as antigen presenting cells. Page 32 Faculty Of Medicine – Sohag University  HEM-210 Fig. (7): Diagram of a monocyte by L.M. E.M. BLOOD PLATELETS, (Fig.8) - minute, colorless, non-nucleated corpuscles found in the blood of all mammals. Their number ranges from 150,000-350,000 /c mm. Their life span is 9-10 days. - By L.M. They appear in stained blood film thin biconvex fusiform disc 2-3 um diameter (smaller than RBCS). They are having thin, pale blue peripheral zone called hyalomere and a thicker granular central region called the granulomere - By E.M. The hyalomere contains a circumferential bundle of microtubules for maintaining shape. The granulomere contains; 1. scattered glycogen granules, dense granules (ADP), lysosomes. 2. membrane bounded canaliculi that open to the surface (surface- connected canalicular system): for discharge of secretory products upon activation of platelets. Page 33 Faculty Of Medicine – Sohag University  HEM-210 3. Dense tubular system: not connected to the surface 4. mitochondria Fig. (8): A diagram of a platelet by E.M - Functions: 1-Initiating blood clotting upon injury of the endothelium. 2-Platelet derived growth factor: secreted on platelet activation and help in repair process. Page 34 Faculty Of Medicine – Sohag University  HEM-210 3 BONE MARROW - Bone marrow is soft, gelatinous tissue that fills the medullary cavities. Types Red bone marrow, known as myeloid tissue, consists of a delicate, highly vascular fibrous tissue containing hematopoietic stem cells. These are blood-forming stem cells. It is called red because of the presence of a vast number of red blood corpuscles. Yellow bone marrow is made mostly of fat and contains mesenchymal stem cells which produce fat, cartilage, and bone. Sites Bone marrow remains red in all body until around the age of 7 years, as the need for new continuous blood formation is high. As the body ages, it gradually replaces the red bone marrow with yellow bone marrow. In adult’s highest concentration of red bone marrow is in bones of the vertebrae, hips (ilium), (sternum) as well as at the metaphyseal and epiphyseal ends of the long bones Fig. 9: red marrow Page 35 Faculty Of Medicine – Sohag University  HEM-210 Hematopoiesis - The process of formation of different blood cells from pluripotent hematopoietic stem cells Site of Hematopoiesis Red bone marrow produces all blood elements The small lymphocytes destined to be T cells leave the bone marrow, and undergoing maturation in the thymus Histological structure of the bone marrow 1-Stroma it is formed of a network of reticular C.T. that supports the cells. 2- The vascular sinuses of the marrow are 50-75 um in diameter. They are lined with a layer endothelial cells joined together by junctional complexes. Transendothelial migration of blood cells involves temporary channel formation through the endothelial membrane. As the blood cell completes its passage through the aperture, the endothelial cell “repairs itself,” and the aperture disappears. A discontinuous basal lamina is seen. 3-Free cells these are the free stem cells, immature and mature cells of all blood elements. 4-Fixed cells these are the reticular cells, fibroblasts, adipocytes and macrophages. Page 36 Faculty Of Medicine – Sohag University  HEM-210 Fig. (10): A diagram of bone marrow Histological structure of the bone marrow - These are pluripotential cells that can generate all of blood cell types. They give rise progenitor cells. Progenitor cells 1- Common myeloid progenitors give rise to either: megakaryocyte/erythrocyte progenitors granulocyte/monocyte progenitors Page 37 Faculty Of Medicine – Sohag University  HEM-210 2- Common lymphoid progenitors give rise to lymphocytes Fig. 11: Hemopoietic stem cells Development of erythrocytes (erythropoiesis) 1.Pluripotential stem cells Colony forming unit erythropoietin sensitive cells (CFU-e) (from commn myeloid progenitor). 2.Proerythroblasts 3.Basophil erythroblasts large number of ribosomes that start to synthesize hemoglobin. 4.Polychromatophil erythroblasts contain hemoglobin in their cytoplasm 5.Orthochromatophil erythroblasts or normoblasts have pink cytoplasm with only faint ting of blue. 6.Polychromatophil erythrocytes or reticulocytes these are immature R.B.Cs result from extrusion of the nucleus of normoblast and contain a small number of ribosomes Page 38 Faculty Of Medicine – Sohag University  HEM-210 - It can be seen in the Peripheral blood but not more than 1%. Its number is clinically useful in estimation of the rate of erythropoiesis in patients suffering from anemia or recovering from blood loss. Granulopoesis( fig. 13) 1. Pluripotential stem cells - commn myeloid progenitor. granulocyte monocyte progenitor 2. Myeloblasts: devoid of granules. 3. Promyelocytes contains numerous azurophilc granules. 4. Myelocytes and metamyelocyte: contain specific cytoplasmic granules 5. Band cells or stab cells: the nucleus is elongated and curved. Fig. 13: Granulopoesis Fig. 12 :(erythropoiesis) Page 39 Faculty Of Medicine – Sohag University  HEM-210 Development of non-granular leucocytes Lymphopoiesis steps of Development of lymphocytes from hematopoetic stem cell Monopoiesis Steps of Development of monocytes from hematopoetic stem cell Development of blood platelets (thrombopoiesis) Thrombopoiesis refers to the development of either thrombocytes (in lower vertebrates) or platelets. It passes through steps till become Megakaryocytes (fig. 14) Fig. 14: thrombopoiesis Megakaryocytes (fig. 15) Page 40 Faculty Of Medicine – Sohag University  HEM-210 These are giant cells (50-70 um) with single, large, lobulated polyploid nucleus (due to increase their DNA content without undergoing late stages of mitosis) Fig. 15: Megakaryocytes Mechanism of platelet formation (fig. 16) - Cytoplasmic extensions from megakaryocytes called proplatelets processes develop. - The proplatelet processes pierce through sinusoidal endothelium (transendothelial) extend into the sinusoidal blood and at transverse constrictions appear throughout the proplatelet called Platelet demarcation membranes release platelets. Page 41 Faculty Of Medicine – Sohag University  HEM-210 Fig. 16: Platelet formation References: -Alan Stevens, James S.Lowe. 3rd edition --Illustrated Interactive Q&A: L Illustrated Q&A -Review of Histology. Guiyun Zhang, Bruce A. Fenderson Page 42 Faculty Of Medicine – Sohag University  HEM-210 Page 43 Faculty Of Medicine – Sohag University  HEM-210 1 Hemoglobin Definition It is an example of chromo- and metallo-conjugated proteins. It is formed of a tetramer of polypeptides of two types that differ according to its developmental stage of expression to meet specific requirements. It fills up the entire space of RBCs where it carries several functions as follow Function 1-Carrier of oxygen from its high tension in the lung to its low tension in the peripheral tissues. 2- Carrier of carbon dioxide as carbonium with amino groups of its amino acids from tissues to the lung. 3- Strong buffer that is essential for pH maintenance in RBCs and affect O2 transport (Bohar's effect). 4- Its genetic and/or metabolic abnormalities cause serious diseases. Structure of heme - Heme is a complex of iron (in ferrous state, F ) and one of porphyrins called: protoporphyrin IX. Iron is held in the centre of heme molecule by bonds to the 4 nitrogen atoms of pyrrole rings of protoporphyrin - Heme containing proteins are called hemoproteins, metallo and chromoproteins. They include : 1-Hemoglobin and myoglobin. 2- Respiratory cytochromes and microsomal cytochrome P450 3-Catalase, peroxidase and tryptophan oxygenase Page 44 Faculty Of Medicine – Sohag University  HEM-210 The role of the heme group in each protein is: 1- In hemoglobin and myoglobin: Acts as oxygen carrier. 2- In cytochromes: Acts as an electron carrier for hydroxylation reaction s and energy production. 3- In catalase and peroxidase: Acts as a part of active site of the enzyme that catalyzes the breakdown of hydrogen peroxide (H2O2 ). Hemoglobin: Hemoglobin: Globin: - It is formed of a it is a basic protein formed protein part, globin, of 4 polypeptides and a non-protein (tetramer) of two types part, heme prosthetic -At the center of group, bound each polypeptide there is a together; therefore, it heme group. Thus each is a type of polypeptide binds an O2 conjugated metallo- Hemoglobin is and chromo-protein. classified structurally according to the types of these polypeptides as follows. Page 45 Structural types of normal hemoglobin Faculty Of Medicine – Sohag University  HEM-210 A) Hemoglobin A (HbA ): - It is the major hemoglobin in adults (90_95%) - Its globin compromise 4 polypeptide chains two -chains (141 amino acids ) and two -chains (146 amino acids ) The globin is abbreviated 22. - The iron of each heme group is bound by coordination bonds to nitrogen atoms of imidazole rings of histidine amino acids number 58 and 87 in -chains and number 63 and 92 in  chains. - When hemoglobin is oxygentaed , the bonds between iron and histidine residues number 87 in  chains and number 92 in  chains are displaced by oxygen B) Hemoglobin A (HbA2 ): It is the minor adult hemoglobin accounting for about 2.5% of adult human hemoglobin. Its globin consists of 2  chains and 2 delta chains(): 22. C) Fetal hemoglobin (HbF): -This is hemoglobin present in fetus during intrauterine fetal life. It consists of 2  chains and 2 gamma chains. (22). -Hemoglobin F accounts for about 1% of adult human hemoglobin. Unlike HbA1 it resists denaturation by alkalis. -It binds 2,3-diphosphoglycerate weaker than HbA and therefore has higher affinity to O2. Page 46 Faculty Of Medicine – Sohag University  HEM-210 D) Embryonic or growing hemoglobin (HbG): - It is formed in erythrocytes of the first three intrauterine life of baby. It consists of 2 alpha  chains and  chains, 22. Abnormal hemoglobin Hemoglobin A1c ( Glycated hemoglobin ) : - Hemoglobin A, reacts non-enzymatically with glucose to form a derivative known as glycated hemoglobin or HbA1c. - Normally the concentration of HbA1c is very low(5-8%) but in diabetes mellitus,where blood suger level is high,the concentration of HbA1c may reach 12% or more of total hemoglobin - It is used for long-term (several weeks) surveillance of diabetes mellitus. NOTE - Normal vallue of Hb: Blood hemoglobin content is 12-18 g/dL in females and 13- 20 g/dL in males Synthesis of hemoglobin: Three components are required: Protoporphyrin IX:. Globin: Produced by the usual mechanisms of protein synthesis. Iron. Page 47 Faculty Of Medicine – Sohag University  HEM-210 In addition to the actual constituents of haemoglobin, certain vitamins and other factors are also required Pantothenic acid Pyridoxal-P Copper Vit C (ascorbic acid Intrinsic factor: It is necessary for vit B12 absorption. Vit B12 and folic acid: Erythropoietin Heme synthesis δ-ALA synthetase enzyme is very unstable, low in concentration in tissues, Main rate-limiting enzyme in the synthetic pathway Synthesis of Hb appears to proceed concurrently with the maturation of erythrocytes. The primitive red cells contain free porphyrins rather than Hb. As the red blood cells mature, the content of free porphyrin decreases and that of Hb rises. These biochemical changes are correlated with the alterations in the staining properties of the cells. PORPHYRIAS When the blood levels of coproporphyrins and uroporphyrins are increased above normal level and excreted in urine/faeces, the condition is called porphyria.. Page 48 Faculty Of Medicine – Sohag University  HEM-210 HMP SHUNT Definition - It is an alternative minor pathway for glucose oxidation that does not produce ATP nor utilize it. It aims at producing NADPH.H+ and ribose. It is considered as a shunt from the main stream of glycolysis. Biomedical Importance: Though it is oxidation of glucose, but it is not meant for energy Provides NADPH which is required for various reductive synthesis in metabolic pathways. Provides pentoses required for nucleic acid synthesis. Deficiency of a particular enzyme leads to haemolytic anaemia, which is of great clinical importance. Page 49 Faculty Of Medicine – Sohag University  HEM-210 Location intracellular location: Organ location cytoplasm Organ location a) its active where NADPH.H+ is needed in: -Adipose tissue & liver : for lipogenesis -Adrenal cortex ,ovaries&testis : for steroid biosynthesis -RBCs : for production of reduce glutathione -retina : for reduction of retinal into retinol b) In many tissues it supplies ribose for nucleotides NOTE HMP never occur in : -non lactating mammary gland -skeletal muscles. Page 50 Faculty Of Medicine – Sohag University  HEM-210 Steps of HMP Shunt Clinical Aspects Haemolytic Anemia due to G6PD Deficiency Amutation present in some populations causes a deficiency of the enzyme- G-6-PD with impairment of generation of NADPH that is manifested as red cells haemolysis when the susceptible individuals are subjected to oxidant group of drugs such as antimalarials, like primaquin and aspirin, etc. Inheritence: Generally transmitted by a sex-linked gene of intermediate dominance. Race: Defect has a high incidence in Negroes. Also found in non-Negro races and seen most frequently in Mediterranean peoples, namely Italians particularly Sardinians and some Greeks. Other races known to be affected include: Indians, Chinese, Malayan and Thais Page 51 Faculty Of Medicine – Sohag University  HEM-210 Clinically Anaemia Fall in blood Hb↓ May be jaundice and Blackenning of urine. - This type of haemolysis is “selflimiting”; older cells are destroyed whereas the younger cells are resistant. Mechanism of Haemolysis Red cells abnormalities associated are as follows: G-SH-low or low normal G-SH stability-low Catalase-low O2 consumption-low Page 52 Faculty Of Medicine – Sohag University  HEM-210 Micro-minerals 2 (Trace elements) Sources: Liver Heart Kidney Organ meats Spleen NOTE Other sources are egg yolk, fish, nuts, dates and beans. Spinach is a poor Functions of Iron source,because of its lower content of iron and some iron Iron plays a number of important roles in the body: is bound to phytate. As a component of : hemoglobin and myoglobin, it is required for O and CO2 transport. cytochromes and non-heme iron proteins, it is required for oxidative phosphorylation. the essential enzyme, (lysosomal) myeloperoxidase, it is required for phagocytosis and killing of bacteria by neutrophils. ⚫ Lactoferrin binds iron in milk, it facilitates the transfer of iron to intestinal receptor in the infant. It also inhibits microbial growth. Body Iron The total body iron of an adult male is 3-5g. It is distributed as follows: RBCs iron(hemoglobin):66% Tissue iron :33% Plasma iron :1% Page 53 Faculty Of Medicine – Sohag University  HEM-210 Tissue iron ; It includes: 1.Ferritin :it is the main 2.Hemosidren :When storage form of iron. A- Available content of iron is high Its protein is called forms Or more than the capacity apoferritin, which can Non-haem of apoferritin, some of carry 24 atoms of iron to iron(29%) iron is found in granules form ferritin.It presents in called hemosiderin. iron stores, e.g., liver, Can be used by tissues These granules are spleen, bone marrow and or there is body need composed of iron,protein intestine. (polymerized ferritin) and polysaccharides. It is an aging sign. 1.Myoglobin : 2.Respiratory cytochromes (b ,c1 ,c ,a , and a3 ) : It is hemoprotein formed of a single haem ring attached These are components to one long of respiratory chain in polypeptide chain. It mitochondria. They act as is present in muscles electron carriers and heart. It acts as B-Non available forms oxygen reserve for (4%) quick utilization by contracting muscles. that can not be used even if there is body needs. It is in the form of hemoproteins, i.e., contained in haem ring 5.Microsomal and Mitochodrial non respiratory 3.Catalase and peroxidase cytochromes: These are a specific group These are two enzymes 4.Tryptophan oxygenase of enzymes that present in that act on the toxic (Pyrrolase) liver, lung, kidney, gut, hydrogen peroxide(H2O2 ) adrenal cortex, heart and converting it into H2O. This enzyme is important for brain. They act as electron tryptophan metabolism. carrier. Page 54 Faculty Of Medicine – Sohag University  HEM-210 Mechanism of iron absorption: Absorption of iron occurs in duodenum and the proximal part of the jejunum. Alterations of plasma iron: a) Iron deficiency anemia: Deficient intake Causes: Impaired absorption: e.g. Steatorrhea, abdominal surger Excessive loss e.g. menstrual loss, gastrointestinal bleeding, bleeding due to some parasites (anchylostoma). Biochemical changes: Plasma iron is decreased. Plasma TIBC is increased. Plasma ferritin is decreased. RBCs are hypochromic and microcytic. b) Iron overload: Note Repeated blood transfusion. Hemochromatosis :This is a rare hereditary disease characterized by Causes: Intravenous administration of iron. abnormal increase of iron absorption. Hemochromatosis (hemosiderosis, Bronz diabetes) Page 55 Faculty Of Medicine – Sohag University  HEM-210 Iron is deposited in the form of hemosiderin in: ⚫ Liver: Causing liver cirrhosis. ⚫ Pancreas: Causing fibrosis and diabetes mellitus. ⚫ Skin: Causing Bronz discoloration of skin. Biochemical changes: Plasma iron is increased. Plasma TIBC is decreased. Plasma ferritin is increased Requirements: ✓ Adults :10 mg/day ✓ Pregnant and lactating women :30 mg /day. Page 56 Faculty Of Medicine – Sohag University  HEM-210 Page 57 Faculty Of Medicine – Sohag University  HEM-210 Page 57 Faculty Of Medicine – Sohag University  HEM-210 1 Introduction Blood is a connective tissue in fluid form. It is considered as ‘Fluid of life’ it carries oxygen from lungs to all parts of the body and carbon dioxide from all parts of the body to the lungs. ‘Fluid of growth’ it carries nutritive substances from the digestive system and hormones from endocrine gland to all the tissues. ‘Fluid of health’ it protects the body against the diseases and gets rid of the waste products and unwanted substances by transporting them to the excretory organs like kidneys. 1) Blood Functions Respiratory Homeostasis Nutrition Haemostasis Excretion Functions Defense Regulation of metabolism Regulation of body temperature Page 58 Faculty Of Medicine – Sohag University  HEM-210 1. Respiratory function Blood carries O2 from lungs to tissues and carries CO2 from tissues to lungs. 2. Nutritive function Blood carries nutrients (glucose, amino acids, fatty acids......) to the tissues. 3. Excretory function Blood carries the waste products (urea, uric acid, creatinine, lactic acid) from the tissues to be excreted by excretory organs as (the kidneys, lungs & skin). 4. Regulation of metabolism Blood carries hormones and vitamins or other physiologically active substances which regulate body metabolism. 5. Regulation of body temperature Blood carries heat from the internal organs to the superficial organs and skin, so excess heat can be lost by conduction, radiation and convection and also by evaporation. 6. Defense function; Through: White blood cells (cellular immunity) which is capable of Phagocytosis. Antibodies (humoral immunity) against foreign proteins. 7. Haemostasis (prevention of blood loss) Through blood platelets & coagulation factors. 8. Homeostasis Regulation of water balance. Regulation of acid-base balance: by chemical buffers in blood. 2) Blood physical properties Color Blood is red in color. Arterial blood is scarlet red because it contains more oxygen. Venous blood is purple red due to presence of reduced Hb. Page 59 Faculty Of Medicine – Sohag University  HEM-210 Specific Gravity 1030 for plasma 1060 While the specific gravity of water is 1000 it is for Whole Blood 1090 for erythrocytes Osmotic pressure the colloidal O.P is (25-30mmHg) It is greatly due to albumin which has the highest concentration of all plasma proteins. Viscosity Taking viscosity of water unity The viscosity of the plasma is about 2 (due to presence of plasma proteins mainly fibrinogen. Viscosity of whole blood is about 5 (due to presence of R.B.Cs). So it is in polycythemia or dehydration in anemia or Hypoproteinemia. Volume Average volume of blood in a normal adult is 5 L. In a newborn baby, the volume is 450 ml. In females, it is slightly less and is about 4.5 L. It is about 8% of the body weight in a normal young healthy adult, weighing about 70 kg. Page 60 Faculty Of Medicine – Sohag University  HEM-210 NOTE Blood volume is higher in males due to genetic and body-built difference. 3) Blood Components Cellular Component Fluid Part (Plasma) Represents 55% of blood volume Red blood cells (RBCs) or Erythrocytes 90% Water White blood cells (WBCs) or Leucocytes 7-8% plasma proteins 0.9% Electrolytes Blood Platelets or Thrombocytes 1-2% Others: nutrients, Waste products, hormones, blood gases, dugs….etc. 2 Plasma Proteins 100 cc of plasma contain 7-8 gm plasma proteins which are Albumin 4.5gm Globulins 2.7gm Albumin/Globulin ration (A/G ratio) Fibrinogen 0.4gm It is about 1.2-1.6 It decreases in I. Liver diseases: due to a) ↓ formation of albumin b) ↑ formation of globulin Formed By liver Page 61 Faculty Of Medicine – Sohag University Destroyed by tissues  HEM-210 II. Renal diseases due to loss of albumin in urine. Dynamic state of plasma proteins Plasma proteins are dynamic structure. They are continuously formed from amino acids in the liver. They are continuously destroyed into amino acids which are used by the tissues. Rate of formation 6-10% = rate of destruction 10% Site of synthesis of plasma proteins Albumin and fibrinogen: formed only by the liver. Globulins: formed not only in the liver but also by the cells of the reticuloendothelial system which are present in the liver, spleen,bone marrow and lymph glands.  So, in liver diseases albumin and fibrinogen levels decrease but globulins are compensatory increased. 1) Sources of plasma Proteins Diet proteins high biological value proteins (containing all essential amino acids) produce more plasma proteins than those of a low biological value. Tissue proteins the plasma proteins could be regenerated from tissues even in complete starvation of animal, they are classified into Labile protein immediately added from liver and tissues to the plasma. Reserved protein slowly regenerated and moved from liver and tissues to plasma this occurs at the expense of tissue proteins. Fixed cell proteins form apart of the cell membrane and cannot be changed into plasma protein at all. Page 62 Faculty Of Medicine – Sohag University  HEM-210 2) Functions of plasma Proteins 1. Maintenance of plasma colloidal osmotic pressure Achieved by plasma proteins mainly Albumin About (25-30 mmHg) Important for regulation of blood volume 2. Defense function Because the antibodies are mainly gamma-globulins 3. Clot formation Fibrinogen plays an important role in clot formation 4. Viscosity Plasma proteins mainly fibrinogen give viscosity to the plasma which is important for maintenance of peripheral resistance and hence arterial B.P. 5. Carriers Plasma proteins act as carriers for Hormones, Metal ions, Fatty acids & amino acids or Drugs. 6. Buffers If acids is added (e.g. lactic acid as during muscular exercise) Lactic acid + Na proteinate → Na lactate + Proteinic acid. If an alkali is added: NaOH + Proteinic acid → Na proteinate + H2O 7. CO2 carriage in the form of carbamino protein. 8. Capillary permeability regulation by blocking the pores of the capillaries. 9. Diet reserve Plasma proteins are dynamic structure i.e. continuously destroyed into amino acids which are used by the tissues. Can be utilized during starvation. Page 63 Faculty Of Medicine – Sohag University  HEM-210 Red Blood Corpuscles (RBCs) 6 Erythrocytes Shape circular, biconcave, non-nucleated discs.  Biconcavity of RBCs is achieved by the presence of Ankyrin and Spectrin proteins in the cell membrane of RBCs.  Lack of these proteins leads to spherical shaped RBCs, a condition that called "spherocytosis". Normal Count In males 4.6:6.2 million / mm3 (average 5.4 million / mm3). In females 4.2:5.4 million / mm3 (average 4.8 million / mm3). Wall Semipermeable Plastic (i.e. can be momentary deformed when squeezed in narrow capillaries then it regains its original form) Not elastic (i.e. doesn’t elongate on stretch, so when absorbs some water it ruptures) ! Haemoglobin It is a chromoprotein in which four haem groups are attached to a protein part (globin). Each haem group contains an iron atom which can carry one O2 molecule. Globin keeps iron of haem in ferrous state whether in oxy Hb or reduced Hb. If oxidized to ferric state by oxidizing agents, it is converted into methemoglobin which isn’t capable of carrying oxygen. ! Page 64 Faculty Of Medicine – Sohag University  HEM-210 Types of normal Haemoglobin The haem molecule of haemoglobin doesn’t vary in composition, but the globin molecule is the responsible for the different types of haemoglobin. Globin is formed of 2 identical halves each half consists of 2 polypeptide chains: Hb A (normal adult Hb representing 97%) formed of 2α & 2β chains Hb A2 (normal minor adult Hb only 3%) formed of 2α & 2δ chains Hb F (normal fetal Hb) formed of 2α & 2γ chains Gower I Hb (formed of 4ε) & Gower II (formed of 2α & 2ε) Both are the embryonic Hb 1) Functions of RBCs Functions of the content 1. Haemoglobin Has a respiratory function, It transports O2 from lungs to tissues & CO2 from tissues to lungs Has a buffer action (i.e. helps in keeping the blood PH constant) 2. Carbonic anhydrase Important in CO2 carriage. 3. Histaminase enzyme for destruction of histamine. 4. Glucose-6-phosphate dehydrogenase protect RBCs from toxic H2O2 Functions of the wall 1. Allows the RBCs to pass through the narrow capillaries due to its plasticity 2. The biconcavity of the membrane gives the RBCs a large surface area which helps the exchange of gases. 3. It is semipermeable (i.e. it regulates the passage of electrolytes to the inside and the outside of the cell) 4. Permits the passage of HCO3- and Cl- but doesn’t allow the passage of H+ and K+. 5. keeps the content inside the RBCs protecting carbonic anhydrase enzyme from being lost in urine & protect Hb from being free in plasma. Page 65 Faculty Of Medicine – Sohag University  HEM-210 2) Origins of RBCs Erythropoiesis the process of the origin, development and maturation of erythrocytes Site Beginning from the 4th week of pregnancy and all over the 1st six months of fetal life it occurs in the stem cells of yolk sac, liver and spleen. In the last 3 months bone marrow becomes the most active site. In infants & young children bone marrow becomes the only site for erythropoiesis. In adults erythropoiesis is limited to the red bone marrow (which is present in the ends of long bones, vertebrae & flat bones). Stages of formation Basophil Polychromatophil Acidophil Heamocytoblast Pro-erythroblast Reticulocyte RBCS erythroblast erythroblast Erythroblast During maturation The nucleus becomes smaller until it disappears from the mature RBCs. There’s progressive ↓ in the size of the whole cell. Appearance of hemoglobin Change in the staining properties of the cytoplasm LIFE SPAN OF ERYTHROCYTES Erythrocytes live for about 120 days. The number of red cells is kept nearly constant by a balance between the rate of destruction & the rate of regeneration. FATE OF OLD ERYTHROCYTES The old red cells at the end of their life are taken up by the phagocytic cells of the RES then: Hb molecule is broken into haem + globin. Globin is used by the body or stored for future use Page 66 Faculty Of Medicine – Sohag University  HEM-210 Haem losses its iron and is converted into bile pigments which then excreted by the liver to the small intestine then excreted with stool Iron is used by the body for reformation of RBCs or stored in the liver as ferritin for future use. NOTE Bile Pigments are responsible for the brown coloration of the stool. 3) Factors affecting erythropoiesis 1. Oxygen tension of arterial blood Oxygen tension of arterial blood is the main stimulus for erythropoiesis, as Lowering of oxygen tension stimulate bone marrow to produce more RBCs Doesn’t act directly on bone marrow but through the release of Erythropoietin hormone  Conditions that decrease O2 supply to the tissues increases the rate of production of erythrocytes as occurs in: High altitude Increase demands for O2 in athletes. Chronic respiratory disease (e.g. COPD) Anemia Prolonged heart failure 2. Kidney As a result of O2 lack, the endothelium of peritubular capillaries of the kidney release a substance called erythropoietin hormone. The kidney secretes 85% of erythropoietin. The liver secretes the remaining 15%. Erythropoietin hormone stimulates bone marrow to produce more RBCs  Explain: anemia in renal failure 3. Hormones Specific → Erythropoietin Non-specific → thyroxin, testosterone  Explain: number of RBCs in male is more than that in females Page 67 Faculty Of Medicine – Sohag University  HEM-210 4. Liver Produces → globin of haemoglobin & 15% of erythropoietin. Stores → iron &vitamin B12  Explain: anemia in liver failure. 5. Bone marrow Healthy bone marrow is essential in erythropoiesis. If bone marrow is destroyed by prolonged exposure to X-rays, atomic radiations or drugs → results in aplastic anemia ! 6. Food factors I. Iron essential constituent of Hb molecule. Iron deficiency results in anemia Absorption of iron: o Iron absorption takes place in the upper part of the duodenum o Most of inorganic iron in food is in ferric state. Iron is reduced to ferrous iron in the stomach by vitamin C in the presence of HCl o Mucosal cells manufacture a protein called (apoferritin) which combines with iron to form (ferritin) o when all apoferritin is converted to ferritin, iron absorption is stopped, and the excess iron will be excreted in feces Ferritin is in equilibrium with iron in the plasma so; fall of iron concentration in the plasma is followed by separation of iron from ferritin and is transported by beta globulin into circulation in the form of Transferritin II. Vitamin B12 Important for nuclear maturation & normal development of RBCs Deficiency of Vit. B12 results in failure of nuclear maturation and cell division in bone marrow → megalocytes appear in peripheral blood which is larger in size than normal RBCS, Oval in shape, less in number, large amount of Hb, and of shorter life span. Absorption o It is absorbed from the terminal ileum o Vit B12 is called the extrinsic factor. It combines with intrinsic factor secreted by parietal cells of the o stomach.to protect Vit. B12 from digestion. It is stored in the liver Page 68 Faculty Of Medicine – Sohag University  HEM-210 III. Folic acid Folic acid, like Vit. B12 is needed for maturation of RBCs Its deficiency leads to megaloblastic anemia Absorbed from jejunum IV. Proteins Proteins of high biological value are needed for synthesis of haemoglobin. V. Trace elements Copper and Cobalt act as catalyst for the synthesis of Hb but do not enter in the formation of Hb. Copper deficiency leads to anemia. Cobalt enters in the formation of Vit. B12 and stimulate Erythropoietin formation. So, excess cobalt may produce polycythemia NOTE Absorption of: Iron Duodenum Vit B12 Ileum Folic Acid Jejunum Page 69 Faculty Of Medicine – Sohag University  HEM-210 8 Anaemia Anemia 1-normal level of haemoglobin It’s a decrease in the quality or Males: 16grams/dl quantity of RBCs. Females:14grams/dl Blood count: when No. of RBCs is If the haemoglobin level drops below 5 millions. below normal, the condition is Hb estimation: when Hb level is called Anaemia. below 12 gm / dl. Causes of Anemia A. Antigen-Antibody reaction as in incompatible blood transfusion. B. Bacterial toxins and malaria. 1. Excessive C. Chemicals: as in lead poisoning. destruction of D. Drugs: as sulfa. RBCs E. Enzyme deficiency: as in favism there ↓ in G6PD (haemolysis) enzyme. F. Snake venom. G. Blood diseases: as spherocytosis or sickle cell.anaemia This is may be due to: A. Prolonged exposure to X-rays. 2. Aplastic B. Exposure to atomic radiations. anaemia C. Malignant diseases infiltrating the bone marrow..D. Drugs as chloramphanicol 3. After haemorrhage Page 70 Faculty Of Medicine – Sohag University  HEM-210 HEM-210 This is may be due to: Defective intake, Defective absorption or 4. Iron deficiency increased iron requirements. anaemia The RBCs are small in size and pale in colour This is may be due to: 5. Vitamin Stomach diseases or its removal : B12deficiency Lack of intrinsic factor. (pernicious anaemia) Disease or removal of lower ileum. This is may be due to: 6. Folic acid Increase its requirements in the pregnant deficiency women in the first 3 months of pregnancy. Page 71 Faculty Of Medicine – Sohag University  HEM-210 9 Blood groups The surface of the RBCs contains many antigens (agglutinogen) the most important of these antigens are the A and B antigens Blood groups According to the presence or absence of these antigens, people are divided into 4 groups: 42% group A contain A antigen on R.B.Cs and anti-B in plasma 9% group B contain B antigen on R.B.Cs and anti-A in plasma. 3% group AB contain both A & B antigens and no anti Bodies in plasma. 46% group O contain neither A or B antigen and both anti-A, anti-B in plasma This is important in blood transfusion Blood transfusion Donor A B AB O Recipient Group A ✔ ✖ ✖ ✔ Anti B Group B ✖ ✔ ✖ ✔ Anti A Group AB ✔ ✔ ✔ ✔ No antibodies Group O ✖ ✖ ✖ ✔ Anti A &Anti B Page 72 Faculty Of Medicine – Sohag University  HEM-210 Each blood group can donate and receive blood from persons with the same blood group (after cross matching test) Blood group AB is a universal reciepient as there are no antibodies in their plasma. Blood group O is a universal donor as their RBCs don’t contain antigens on their surfaces. It is rare that the transfused blood (from the same group if it contains foreign antigens or from group O) causes agglutination of the recipient’s blood because the plasma of donor’s blood immediately becomes diluted by recipient’s plasma. And this can be avoided by the cross matching test. Determination of blood groups: By using anti A and anti B antibodies RH Factor There is another antigen on the surface of R.B.Cs called Rh.Factor. It is determined by the presence of the D antigen. It is firstly discovered in rhesus monkey and present in 100% of these monkeys (all are RH +ve). In people, D antigen is found in 85% of persons and are said to be (Rh+ve). But 15% have no D antigen on their R.B.Cs and are said To be (Rh -ve). The plasma of either Rh +ve or Rh –ve persons doesn’t contain antibodies against Rh. factor naturally. Importance of RH Factor 1) Blood transfusion 2) in marriage If Rh–ve person receives Rh +ve blood When an Rh-ve woman is married to an for the first time antibodies are Rh +ve man, the fetus genetically almost developed in his plasma but no will be Rh +ve like his father. agglutination occur. Page 73 Faculty Of Medicine – Sohag University  HEM-210 HEM-210 If second transfusion of Rh +ve blood Small amount of fetal blood may leak occurs → serious agglutination and into the maternal circulation during haemolysis occurs delivery when the placenta is separated from the uterus so anti-D antibodies will be formed. When Rh–ve blood is transfused to Rh– During the next pregnancy these ve or Rh +ve blood no harm occur. antibodies cross the placenta and reach the fetus causing agglutination and haemolysis of his R.B.Cs. The condition is called erythroblastosis fetalis and the baby is born usually dead. Note If the baby is born alive he will suffer from anaemia, jaundice and may be kernictrus. Erythroblastosis fetalis can occur in the 1stpregnancy if the mother receives Rh +ve blood before pregnancy. Rh incompitability may not occur in Rh–ve mothers if the previuos babies were Rh–ve or due to different blood groups so, fetal RBCs destructed by maternal antibodies Treatment and prevention Treatment: If the baby is born alive with erythroblastosis fetalis can be treated by blood exchange by a blood group O Rh–ve Prevention: Rh-ve women must not receive Rh +ve blood even before marriage. If Rh-ve woman marries Rh +ve man she must be given anti D antibodies within 72 hours after any delivery or abortion Page 74 Faculty Of Medicine – Sohag University  HEM-210 HEM-210 Cross matching test It is performed prior to a blood transfusion, to determine if the donor's blood is compatible with the blood of an intended recipient or not even if they have the same blood group and the same Rh factor to avoid: 1)Subgroup incompatibility. 2)High concentration of antibodies in the donor's blood. (As in case of giving group O blood to a group A recipient) 3) blood transfusion 1) indication of blood trasfusion 2) complication of blood transfusion RBCs loss: as in massive What are the causes of death with haemorrhage, haemolysis. incompatible blood transfusion? Plasma loss: as in severe burns. Anuria and renal failure. Thrombocytopenia or deficiency in Arrhythmia. Due to K+ release coagulation factors. Shock. Due to allergy and histamine Severe anaemia. release. 10 White blood cells (leucocytes) ( Normal count 4000-11000 mm3 ) Page 75 Faculty Of Medicine – Sohag University  HEM-210 According to the presence or absence of 1) Types of leucocytes granules in their cytoplasm, leucocytes can be classified into 1) granular 2) Non granular leucocytes leucocytes(granulocytes) (agranulocytes) Neutrophils 60- 70% Contain fewer granules Eosinophils 2- 5% Lymphocytes 15-25% Basophils 0- 1% Monocytes 2-8% Granulocytes and monocytes are formed only in bone marrow Lymphocytes are formed mainly by lymphatic tissue but also in Origin bone marrow to a lesser extent. 2) Function of leucocytes Eosinophils : Basophils : Weak phagocytes Not phagocytic Attack parasites. They secrete histamine and contain They collect at sites of allergic about half the amount present in the reactions. It may destruct histamine body. released in allergic conditions (it They secrete (anticoagulant) contains histaminase enzyme). heparin release plasminogen needed for lysis of blood clots Page 76 Faculty Of Medicine – Sohag University  HEM-210 Neutrophils : Lymphocytes They have a defensive action The small lymphocytes have 2 types: against invasion of microorganisms They have highly phagocytic (microphages) A. Diapedesis: They migrate from blood stream by passing through the pores between endothelial cells of capillaries to reach the tissue spaces. B. Movement: They move through the tissue spaces by amoeboid movement C. Chemotaxis: They attracted to bacteria by chemical agents known as leucotaxin. leucotaxin is bacterial products interact with plasma factors. D. Phagocytosis: Finally neutrophils ingest and digest bacteria by their proteolytic.enzymes as myeloperoxida Monocytes : Highly phagocytic (macrophages): It can engulf large sized particles as R.B.Cs, tissue debris, malaria or large No. of bacteria (about 100). Have role in tissue repair after inflammation by removing the tissue debris & supply proteins and lipids necessary for healing Page 77 Faculty Of Medicine – Sohag University  HEM-210 Life span & Fate Life span: Neutrophils: 1-2 days. Lymphocytes: few hours up to years according to type. Monocytes and macrophages: months or year Fate: Phagocytosed by cells of the RES Page 78 Faculty Of Medicine – Sohag University  HEM-210 11 Lymphatic system Introduction: Homoeostatic mechanisms are required to maintain the constancy of the fluid around each body cell. Many substances that cannot enter or return through the capillary walls, including protein molecules, are returned to the blood as lymph. Lymphatic system is a closed system of lymph vessels, through which lymph flows, it's a one way system. It's consists of lymph vessels, ducts, nodes and other tissues 1) Lymph Lymph is derived from blood as filtrate and circulates around the body (including lymph nodes, liver and spleen) in lymph vessels Factors increasing the flow of lymph Flow of the lymph is promoted by the increase of lymph Blood capillary pressure Interstitial fluid pressure Permeability of lymph capillaries Surface area of lymph capillary by means of dilatation Functional activities of tissue Page 79 Faculty Of Medicine – Sohag University  HEM-210 Function of the lymph Important function of lymph is to return the proteins from tissue spaces into blood Bacteria, toxins and other foreign bodies are removed from tissues via lymph Maintenance of structural and functional integrity of tissue obstruction of the lymph flow affects various tissues, particularly myocardium, nephrons and hepatic cells Important route for intestinal fat absorption this is why lymph appears milky after fatty meal It's play an important role in immunity by transport of lymphocytes 2) Lymph nodes Lymph nodes are small glandular structure located in the course of lymph vessels, the lymph node also called lymph gland Function of the lymph nodes Lymph node work as filters to filter bacteria, viruses, parasites, other foreign materials (even cancer cells) that are brought to the node via lymphatic vessels Antibodies production Trapping antigens by phagocytes Lymphopoiesis: LN is the site of maturation of some lymphocyte and monocytes 3) Spleen The spleen is the largest lymphoid organ in the body The spleen has a very rich blood supply and may contain more than 500ml of blood Page 80 Faculty Of Medicine – Sohag University  HEM-210 Function of spleen: Formation of RBCs in early fetal life Destroys old, damaged and abnormal RBCs and storage the iron found in hemoglobin for future use. (RBCs undergo extreme ,deformation during passage from the cords into the sinusoids. Old damaged and abnormal RBCs have ↓ elasticity, so entrapped in )cords & phagocytosed by cordal macrophages Reservoir for monocytes, which can quickly leave the spleen to help repair damaged tissue anywhere in the body during an emergency Reservoir for blood that can be returned to the cardiovascular system when needed Defensive function: 1-Macrophages of spleen engulf bacteria and other infectious agents 2-Lymphoid cells of the spleen react against infections by formation of antibodies. Contains about 25% of T & 15% of B lymphocytes 4) Reticuloendothelial System It is a general phagocytic system located in all tissues, especially in those tissues where large number of organisms, particles and toxins are to be destroyed. Origin: almost all these cells originate from monocytic stem cells therefore, the RES is almost synonymous with the monocyte macrophage system.. RES consist of: 2-mobile tissue 3- Fixed tissue 1- monocytes macrophage macrophage Page 81 Faculty Of Medicine – Sohag University  HEM-210 Function of RES Phagocytic Function: Bacteria, other foreign bodies and tissue debris are engulfed and digested by the lysosomes of the macrophages Destruction of senile red cells Storage and metabolism of iron Formation of bile pigments Fixed tissue macrophage: (Known by different names in different sites) Liver: Kupffer CNS: Microglia Bones: Osteoclasts cells Lungs: Alveolar macrophages Connective tissue: Histiocytes Spleen/Bone marrow/Lymph nodes: Reticular or Dendritic cells Skin: Langerhans cells Page 82 Faculty Of Medicine – Sohag University  HEM-210 12 Blood platelet(thrombocytes) (thrombo = clots ; cytes = cells ) Count and formation: Count = ¼ - ½ million / mm3 They are formed from mother cell in bone marrow called megakarocyte (one megakarocyte gives 4000 platelets) Life span = 8-12 days (removed by RES specially spleen) so splenectomy causes an increase in platelet count Structure of platelets: 1-Platelet Membrane invaginates inside the platelets forming. canaliculi and also contains: Receptors for collagen, vessels wall, thrombin, Von Willebrand.Factor (vWF) and fibrinogen Coat of glycoproteins: that prevents platelets adherence to normal endothelium but help the platelets adhesion to injured.vessels 2-platelet cytoplasm: that contains Microfilaments (actin and myosin for clot retraction) and microtubules Two types of granules: 1- Alpha granules: contains vWF, fibrinogen, platelet factor 4(PF4),beta thromboglobulin,and platelet derived growth factor (PDGF) 2-Dense granules (delta granules): contains ADP & serotonin Page 83 Faculty Of Medicine – Sohag University  HEM-210 Prevention of blood coagulation in normal vascular system: 1-Endothelial surface factors: By 1- Smoothness of the endothelium: This prevents platelet.aggregation or activation of clotting factors 2-Presence of negatively charged protein on the inner surface ,Of endothelium: This repels clotting factors and platelets so Prevent activation of clotting factors 3- Healthy vascular endothelium secretes Nitrous Oxide (NO) and prostacyclin (PGI2) that inhibit platelet aggregation 4- presence of a protein bound with the endothelial membrane called thrombomodulin,which act as antithrombin factor 2- Presence of 1-Anti thrombin III: activated by heparin and removes Activated thrombin 2-Alpha 2-macroglobulin: has the same function as antithrombin III but not activated by heparin 3- Thrombomodulin 4-Heparin: anticoagulant secreted by basophils and mast cells in connective tissue around the capillaries 5-Prostacyclin: released from endothelium and inhibits platelet aggregation Page 84 Faculty Of Medicine – Sohag University  HEM-210 3-Lysis of blood clots by fibrinolysin (plasmin): Released from eosinophils in an inactive form (plasminogen) Activated by: 1-Tissue plasminogen activator (tPA) which released very slowly from the injured vessel 2-Urokinase-type plasminogen activator: originally isolated from human urine, and it is also present in the blood 3- Active factor XII and thrombin 4 - Thrombin 3 - Active factor XII It causes lysis of blood clot and destruction of many clotting factors, as fibrinogen, prothrombin, factors V, VIII & XII It removes the remaining unnecessary blood clot & reopens many small blood vessels in which blood flow has been blocked by clots 4- Presence of coagulation factor in an active form: In addition to removal of some activated coagulation factors by circulating blood and their inactivation in the liver. 5- Normal dynamic circulatory state Because slowing of the blood flow helps in accumulation of the activated factors and enhances intravascular clotting. Page 85 Faculty Of Medicine – Sohag University  HEM-210 13 Hemostasis Definition: stoppage of bleeding Hemostasis can be divided into two stages :- Primary hemostasis: includes the platelet and vascular response to vessel injury Secondary hemostasis includes the coagulation factors response to such injury Together, platelets, vessels, and coagulation factors combine to stop bleeding and allow for vessel repair through formation of a stable fibrin-platelet plug at the site of injury. Steps of hemostasis: 1-Local vasoconstriction of the injured vessel by: 1-Myogenic mechanism: contraction of smooth muscles in the blood vessel wall as a result of the trauma 2-Neurogenic mechanism: by nervous reflexes initiated by pain sensation that activate sympathetic fibers leading to vasoconstriction. 3-Chemical mechanism: by serotonin released from activated platelets P