Blood Flashcards
What does red bone marrow do?
form blood cells
What is blood?
a specialised fluid connective tissue
What are the functions of blood?
- gaseous exchange
- transport of nutrients, hormones, antibodies, water and metabolic wastes
What are the 3 components of blood?
- plasma (55%)
- buffy coat (1%)
- RBCs (45%)
What are the 4 components of plasma?
- water
- proteins
- electrolytes
- dissolved gases
What are the 2 components of the buffy coat?
- platelets
- WBCs
What are RBCs also known as?
erythrocytes
What is the main function of RBCs?
gaseous exchange
What does the biconcave shape of RBCs facilitate?
gaseous exchange and allows more haemoglobin closer to the plasma membrane
What does haemoglobin consist of?
4 polypeptide chains complexed with iron-containing haeme groups
What are the 6 stages of the RBC lifecycle?
- erythropoiesis starts in the bone marrow
- erythrocytes are released into vesicles and circulate for 120 days
- spleen (and liver) macrophages break down old erythrocytes intro bilirubin, iron and amino acids
- liver processes bilirubin into bile
- small intestine excretes bile in faeces
- kidney excretes bile in urine and releases erythroprotien (EPO) to stimulate erythropoiesis
Which ABO blood group has no antibodies present in the plasma?
AB
How can the blood group be determined using clumping?
- if clumping occurs with anti-A, the blood type is A
- if clumping occurs with anti-B, the blood type is B
- if clumping occurs with both, the blood type is AB
- if no clumping occurs with either the blood type is O
- if clumping occurs with anti-Rh, the blood is Rh positive; if not, it’s Rh negative
What is Rh factor?
a protein found on the surface of RBCs
What are WBCs also known as?
leukocytes
What are the 2 groups of WBCs?
- granulocytes
- agranulocytes
What are the 3 types of granulocyte and what % of WBCs do they make up?
- neutrophil (40-75%)
- eosinophil (1-6%)
- basophil (1%)
Describe the nucleus of the 3 types of granulocyte
- neutrophil - highly lobulated
- eosinophil - bilobed
- basophil - bilobed
What are neutrophils involved in?
the acute inflammatory response to tissue; they kill bacteria, fungi and foreign debris
What are signs of acute inflammation?
heat, redness, swelling, pain and loss of function
What do the granules of eosinophils contain?
peroxidase, histaminase, arylsulfatase and other hydrolytic enzymes
How do eosinophils provide defence against parasites?
by engaging in the phagocytosis of antigen-antibody complexes
What do the granules of basophils contain?
hydrolytic enzymes, histamine, heparin sulphate and slow-reacting substance (SRS) of anaphylaxis
What do SRS and histamine do?
cause small blood vessel dilation associated with allergic and inflammatory reactions
What is the action of histamine in endothelial cells?
binds to H1 receptors which produce nitric oxide (potent vasodilator) within the cells
What is the action of histamine in smooth muscle cells?
nitric oxide diffuses in and causes relaxation
What does histamine do to blood vessels?
increase the permeability of the blood vessel walls, allowing more immune cells and other factors to pass through to the site of injury or infection
What are the 2 types of agranulocytes and what is their size?
- lymphocytes (largest WBC)
- monocytes (smallest WBC)
Describe the lymphocyte nucleus
round and densely stained with a small amount of pale non-granular cytoplasm
Where are most lymphocytes present?
both the blood and lymph
What are the 3 functional types of lymphocyte and what are their lifespans?
- T-lymphocytes (long)
- B-lymphocytes (variable)
- natural killer cells (short)
What are T-lymphocytes involved in?
cell-mediated immunity
What are the 3 types of T-lymphocytes and what are their functions?
- cytotoxic T-lymphocytes – recognise and kill the cells with foreign antibodies
- helper T-lymhocytes – release factor to activate B-lymphocytes, CTLs and macrophages to participate in immune reaction
- suppressor T cells – suppress the activity of B-lymphocytes and the immune response
What do B-lymphocytes do?
contribute to humoral immunity by differentiating into plasma cells and producing circulating antibodies
What do natural killer cells do?
attack cancer cells, foreign cells and virus-infected cells (innate immunity)
What is the shape of a monocyte nucleus?
horseshoe
What do monocytes do?
play a chief role in phagocytosis during infections by entering tissues and differentiating to form macrophages which contribute to both homeostasis and disease
Describe innate immunity (specificity, line of defence, response time, memory and components)
- non-specific
- first
- short
- no memory
- skin, mucous membranes, epithelial cells, phagocytes
Describe adaptive immunity (specificity, line of defence, response time, memory and components)
- specific
- second
- longer than innate
- memory via memory cells
- T- and B-lymphocytes
What is adaptive immunity?
immunity developed upon exposure to a specific pathogen that includes humoral and cell-mediated immunity
What are platelets?
small, round biconvex, non-nucleated cells
What are megakaryocytes?
large cells with a lobulated nucleus found in bone marrow
How are megakaryocytes formed?
using endomitosis (mitosis without cytokinesis)
How are platelets formed?
from the cytoplasm of megakaryocytes (thrombocytosis)
What is the major role of platelets?
blood clotting
What are the 3 steps of blood clotting?
- platelets adhere to the site of injury by binding with collagen fibres
- activated platelets attract more platelets to the site of the clot
- thrombin induces the formation of fibrin which stabilises the blood clot
What is plasma?
an aqueous solution of inorganic salts
What are the main plasma proteins and what are their functions?
- albumins – bulk of plasma proteins; transport protein for fatty acids
- globulins – antibodies of the immune system; transport protein for lipids and heavy metal ions
- fibrinogen – soluble protein that polymerises to form insoluble fibrin during blood clotting
What do plasma lipoproteins do?
deliver insoluble lipids from the tissues where they are synthesised to those that utilise, degrade or store them
What are the 2 type of lipoproteins that carry cholesterol?
- high density lipoprotein - carries good cholesterol back to liver
- low density lipoprotein - carries bad cholesterol to tissues for excretion
What is haematopoiesis?
formation of blood cellular components from haematopoietic stem cells by the red bone marrow
What is erythropoiesis?
formation of RBCs
What is thrombocytopoiesis?
formation of platelets
What is granulocytopoiesis?
formation of granulocytes
What is monocytopoiesis?
formation of monocytes
What is lymphocytopoiesis?
formation of lymphocytes
