Human Biology Notes (PDF)

Human Biology Lec.5 tissue - Blood: Is a specialized form of C.T consisting of formed elements ( blood cells ) and a fluid intercellular substance ( blood plasma ). The volume of blood various in the body, 4-5 L in female, 5-6 L n male. The blood circulates around...

Human Biology Lec.5 tissue - Blood: Is a specialized form of C.T consisting of formed elements ( blood cells ) and a fluid intercellular substance ( blood plasma ). The volume of blood various in the body, 4-5 L in female, 5-6 L n male. The blood circulates around the body about 1000 times each day. Its essential work carrying oxygen and nutrients to the cells and removing potentially lethal wastes. Plasma : - Is a liquid medium for carrying various substances in the blood. - 91% of plasma is water , the remaining of plasma consists of various salts and organic molecules. - Plasma proteins ( albumins , globulins , fibrinogen ) are mostly produced by the liver. Plasma proteins maintain osmotic pressure and help regulate PH. Albumin transport other molecules , globulins function in immunity and fibrinogen enable blood clotting. - Globulin : three types α , β , ᴕ : globulin Cellular elements of blood - There are three main types: 1- Erythrocytes ( RBCs ) : small , biconcave cells without nuclei. RBC are highly specialized for oxygen transport. The normal count is 5 million/ml. They have a life of about 120 days How the RBC help transport Carbon Dioxide( CO2 ) : After blood picks up CO2 in the tissues , about 7% is dissolved in plasma and plasma would be  carbonated and bubbled like soft drinks do. Hemoglobin directly transports about 25% of CO2. All the rest of the CO2 (68%) is transported as the bicarbonate ion( HCO3-) in the plasma by the equation : CO2 + H2O ←→ H2CO3 ←→ H+ + HCO3- - 2- Leukocytes (WBCs): differ from RBC in that they are usually larger, have nucleus, and lack hemoglobin. WBC is derived from stem cells in the red bone marrow. WBC fights infection and are important part of the immune system. The normal count is 7000/ml (5000-10000). WBC are classified into: - Granulocyte: includes neutrophils, eosinophils, and basophils. - A granulocyte: include lymphocyte and monocyte. - Granulocyte: - A-Neutrophils: The most abundant of the WBC. Have multi lobed nucleus. Account for 60- 70% of all WBC. - Are usually the first responders to bacterial infection. B. Acidophil or eosinophil: its nucleus mostly with 2 lobes, the cytoplasm contains some what large granules with bright reddish-orange. The normal count is 2- 4%. They increase in number in the event of a parasitic worm infection or an allergic reaction. Basophils: Have a U-shaped or lobed nucleus. Responsible for the production of histamine. The normal count is 0.5-1%. -A granulocyte: There are no granules in their cytoplasm, they are mainly 2 types: a. Lymphocyte: Account for 25-35% of all WBC. The second most abundant type. Produce antibodies , b. Monocytes : It is the largest white blood cell. Its nucleus eccentric, ovoid or kidney shaped. Its normal count is 3-8%.  3. Blood platelets (thrombocytes): result from fragmentation of certain cells. In red bone marrow. They contain protein, which involved in blood clotting , in addition to other clotting agents found in blood plasma. Also vit K is necessary to the production of prothrombin, this vit is made by bacteria that live in the colon. There are several compound in the body needed for blood clot : 1-Platelets 2-Prothrombin 3-Fibrinogen. *Also Ca ions needed for clotting. Blood function : 1- body respiration 2- nutrition 3- waste elimination 4- thermoregulation 5- immune defence 6- acid base balance 7- water balance Muscular tissue Include 3 types : A. Skeletal muscle B. Cardiac muscle C. Smooth muscle A. Skeletal (striated) muscle: Striated (striped) appearance. Voluntary under conscious nervous control Function 1. Attaches to bones. 2. Moves the skeleton B. Cardiac muscle or heart muscle Striated with intercalated discs. Cardiomyocytes attach to one another with specialized cell junctions called intercalated discs. Cell only contain a single nucleus. Involuntary which mean its under the control of autonomic nervous system (unconscious control). C. Smooth muscle Lack of striations of skeletal muscle. Involuntary. Found in G.I.T. , iris of eye , base of hairs ,uterus.  Nervous Tissue Composed of neuron cell. Received the information from environment (stimulus) through sensory receptors. Information sent as electrical and chemical signals and produces proper response. Signals are then sent from brain to effectors where response is initiated.