2. Blood & blood cells Flashcards
(24 cards)
6 Functions of blood
Connective tissue Immunity Transport Haemostasis Heat distribution Maintain homeostasis
Erythrocytes: function, and structure
Transport O2 and CO2
Biconcave
No nuclei/ organelles
Regulation of erythrocytes
Kidney releases erythropoietin
–> Production of erythrocytes from stem cells in bone marrow
What is the structure of Haemoglobin and what does this allow?
4 Polypeptides, each with 1 haem
Haem contains Fe 2+ : binds to 1 O2
-> Can carry 4 O2
Fetal haemoglobin
Higher affinity
Haemoglobin has low affinity for O2 due to conformational shape of globin
O2 binding backs conformation
2nd O2 binds easier
= Cooperative binding
Anaemia
Low blood haemoglobin concentration
Haematocrit
Volume % of RBCs in blood
Mean corpuscular volume
Average volume of a single RBC
Microcytic
Small MCV
Caused by menstruation, GIT lesions, cancer
Failure of haemoglobin synthesis
Normocytic
Normal MCV
Caused by acute blood loss
Macrocytic
Large MCV
DNA synthesis and cell division fail and there is reduced division of progenitor cells
Fewer but larger RBCs
Caused by folic acid deficiency, Vitamin B deficiency
Leukocytes
WBCs
Travel near capillary wall and invade tissue space to fight infections
Polymorphonuclear granulocytes characteristics
Multi-lobed nuclei Cytoplasmic granules 1st on scene Adhere to BV in infected site and migrate to tissue Engulf, kill, destroy Release inflammatory mediators
List 3 Polymorphonuclear granulocytes
Neutrophils (phagocytic)
Eosinophils (allergy)
Basophils (produce Heparin)
B Lymphocytes
Mature in BM
Humoral immunity
Foreign antigen –> Immunoglobulin production
Antibody-antigen reactions
Assist phagocytosis by agglutination, precipitation or opsonisation
Prevent attachment to tissues (Neutralisation)
Passive immunity
Transfer of antibodies
Where do T lymphocytes come from and what is their role?
Derived in BM, mature in Thymus
Cellular immunity
Monocytes
Large single horseshoe shaped nucleus Appear after granulocytes In tissue become macrophages Engulf microorganisms and tissue debris Secrete inflammatory mediators and stimulate angiogenesis
Leukocytosis
Increased number of WBCs
Infection, Cancer
Leukopenia
Decreased number of WBCs
Chemotherapy, HIV
Platelets
Derived from megakaryocytic
Many organelles and granules, No nucleus
Adhere to each other/ damaged BV to form clots
Plasma
Fluid component of blood
Organic and inorganic substances dissolved in water
Plasma proteins
