Blood consists of a fluid portion a formed

Blood consists of a fluid portion & a formed portion

Blood �Fluid Portion: Portion �Formed Portion: �Called plasma (water, �Rbc’s, wbc’s, & dissolved gases, sugars, hormones, wastes) � 55% of blood volume platelets (formed in bone marrow) �~45% of blood volume

Red Blood Cells �rbc’s �Also called erythrocytes (44% of formed blood volume) �Specialized Oxygen transporters

Red Blood Cells �Have no nucleus �Bioconcave disk �~280 million hemoglobin molecules �Release oxygen through diffusion �Can take up small amounts of carbon dioxide

White Blood Cells �Leucocytes �Respond to infections �~1% of total blood volume (can double when fighting an infection) �Have a nuceli �Colorless

White Blood Cells �Leucocytes divided into 3 groups: �Granulocytes; contains neutrophils, basophils & esinophils �Monocytes: can leave blood stream and become macrophages �Lymphocytes: produce proteins (antibodies)

Platelets � Fragments of cells that form when larger cells in the bone marrow break apart � Play key role in clotting; injury occurs substances released by broken blood vessel attract platelets rupture and release chemicals that combine with other blood components to produce enzyme Thromboplastin Ca 2+ ions present, then Thromboplastin reacts with prothrombin to produce thrombin reacts with fibrinogen to produce fibrin

Scabs… �Fibrin (insoluble) forms mesh strands around injured area

Plasma �Fluid portion �medium in which blood cells are suspended �transports carbon dioxide (dissolved in water portion of blood & forms carbonic acid inside cytoplasm of rbc’s) � �carbonic acid diffuses out of rbc’s, into plasma, as bicarbonate ions (carried from tissues to lungs for gas exchange)

Functions of Blood �Transport: ideal pathway for distribution of materials & energy �Digestive system: blood in capillaries of small intestine absorb nutrients (glucose, amino acids) carry to liver � Respiratory system: picks up chemicals & gases and carries them throughout the body � Waste products: uric acid (end product of protein) carried to kidneys; or carbon dioxide which is released at lungs � Hormones & other chemicals: distributed through blood

Blood Types � The ABO System � The presence or absence of type A or Type B antigens on rbc’s determines a person’s blood type (inherited characteristic). � Blood Type A: type A antigen on surface (anti. B antibodies) � Blood Type B: type B antigen on surface (anti. A antibodies) � Blood Type AB: both antigens present (neither A nor B antibodies) � Blood Type O: neither antigen present (both antibodies present) �

Blood Types �These antibodies appear within several months after birth; presence of antibodies causes agglutination. . . clumpin g of rbc’s when incompatible blood types are mixed.

The Rh System �Another group of antigens found in rbc’s is the Rh factor (rhesus monkey); can be Rh +ve or Rh – ve �Person’s with Rh factor on the rbc’s are termed Rh+; persons without. . . Rh- �Rh- usually means person’s do not have antibodies to the Rh factor, but may make them if exposed during blood transfusion or pregnancy.

Immune System Disorders �If T cells or antibodies �Rheumatoid Arthritis is attack the body’s own cells, it’s called autoimmune disorder (inheritance? ) a chronic autoimmune disorder; body’s immune system attacks joints causing pain, stiffness. . .

Allergies �Exaggerated response to a harmless material (pollen, mould); two major types of allergic reactions. . . �Immediate (acute): occurs within seconds of exposure & disappears within 30 mins; specialized antibodies trigger certain cells to release �Delayed: set off by T cells that are sensitive because of a previous exposure to an allergen; reaction is slower

The Lymphatic System � Network of vessels, with � Blood circulates glands & nodes that extends throughout the body that helps to maintain the balance of fluids in the body � Lymphatic vessels collect fluid called “lymph” made up of interstitial fluid (plasma escapes & becomes part of interstitial fluid); bathes all cells of body. � Works with wbc’s to protect body against infection; wbc’s (lymphocytes) mature in lymph nodes (glands)…also contain macrophages (increase in wbc’s…swelling of lymph glands)

Our Defence �Skin: first line of defence (eyelashes, skin…) outer layer of skin is dry & contains bactericides; sweat forms acidic layer �Cell-Mediated Immunity: “nonspecific defences” include macrophages, neutriphils & monocytes � �Neutriphils & monocytes (wbc’s) that kill bacteria using phagocytosis

Our Defences �Macrophages (developed from monocytes) also use phagocytosis � �Found in liver, spleen, brain & lungs…circulate throughout body in blood & interstitial fluid. �

Defences…. � Specific Defences: (antibody-mediated immunity); immunity is developed by specific defences using antibodies. � Antibodies (proteins that recognize foreign substances & act upon them) are variations of genetic make-up that each person develops. � All immune systems are unique… � Specific Immune System is a primary function of lymphocytes; divided into 2 specialized groups. � B lymphocytes (B cells): mature in bone marrow � T lymphocytes (T cells): mature in thymus gland (near heart) � Antigens: molecules found on surface of cells

B & T Cells �B & T cells have �Antibodies have the antigens that allow them to recognize foreign antigens and then respond to them (also found on surface of pathogens) �Antigen receptors on B & T cells allow foreign recognition & response (most are specific) same shape as the antigen receptor, so they can bind and neutralize the antigen (most are specific). �B cell activated (by Helper T cell)…enlarges…divid ed and produces Memory B cells & plasma cells…engulfs pathogen

T cells: Helper, Killer, Suppressor & Memory � Helper T cell: recognizes antigen on surface of macrophage that destroyed it…sends out signal to stimulate more macrophages � Killer T cells: bind with infected cells and destroy them (puncture hole in cell membrane) � Killer T cells can be activated by B cells or respond to invading pathogen on their own � Suppressor T cells: slow & suppress cellular immunity (do not want to destroy normal tissue) � Memory T cells: remain in bloodstream

Review � The lymphatic circulatory system is associated with the vessels of the cardiovascular system � The lymphatic system helps to maintain the balance of fluids in the body � The lymphatic system is an important part of the body’s defence system � There are three lines of defence against invading pathogens: barriers (skin), non-specific defences & specific defences � Non-specific defences are made up of the actions of macrophages, neutrophils & monocytes; all use phagocytosis � Specific, or immune, defences use a wide variety of cells, including B & T cells

Review �Antigens are �Helper T cells, molecules that are located on the surface of a cell and act as an identification badge �Antibodies recognize foreign substances and neutralize or destroy them. B cells are primarily responsible for antibody immunity Suppressor T cells, Killer T cells and Memory T cells work together to create your immunity �Blood is classified as A, B, AB or O…