Session 1 - Blood and the elements Flashcards
Cells of the body are serviced by which two fluids
Blood
Interstital fluid
Blood is composed of..
Briefly describe its function?
plasma and a variety of cells
- transports nutrients and wastes
function of Interstitial fluid
Bathes the cells of the body
Nutrients and oxygen diffuse from blood into interstitial fluid and then into cells
Functions of the blood
Transportation - O2, CO2, metabolic wastes, nutrients, heat and hormones
oRegulation •helps regulate pH through buffers •helps regulate body temperature –coolant properties of water –vasodilatation of surface vessels dump heat
•helps regulate water content of cells by interactions with dissolved ions and proteins
oProtection
•from disease and loss of blood ( white blood cells, clotting)
Which vein is blood taken from ?
median cubital vein
Blood consists of
Plasma 55% - blood plasma consists of 91.5% water & 8.5% solutes (proteins, nutrients, enzymes, hormones, respiratory gases, electrolytes and waste products)
Formed elements 45% - mostly red blood cells
if blood was In a test tube..
Red blood cells would fall to the bottom because they are the heaviest
Plasma at the top because it is lighter
In between is the buffy coat ( White blood cells and platelets)
The 3 blood plasma proteins
oAlbumin
•maintain blood osmotic pressure
oGlobulins (immunoglobulins)
•antibodies bind to foreign substances called antigens
which form antigen-antibody complexes
FYI = An antibody (Ab), also known as an immunoglobulin (Ig), produced mainly by plasma cells - used by the immune system to neutralize pathogens such as bacteria and viruses.
oFibrinogen
•for clotting
The 3 formed elements of blood
Red blood cells ( erythrocytes)
White blood cells (leukocytes) •granular leukocytes –neutrophils, eosinophils, basophils •agranular leukocytes –lymphocytes = T cells, B cells, and Natural Killer cells –monocytes
Platelets (fragments of cells)
AKA -Thrombocytes
Difference between granular and agranular
Granular = Contain conspicuous granules (grains) after staining
Agranular = do not contain the granules after staining
define Haematopoiesis
Stimulus for the manufacture of our blood cells
Formation of blood cells
What are they originally formed from (1st stage) and what do they differentiate into?
oBlood cells are formed from pluripotent haematopoietic stem cells
The pluripotent stem cells differentiated into:
- Myeloid stem cells
- Lymphoid stem cells.
Myeloid stem cell line of development
- progenitor cells = no longer reproduce themselves, committed to form specific cell types
example: CFU-E develops eventually into only red blood cells
*blast cells = have recognizable histological characteristics
–develop within several divisions into mature cell types including RBCs, platelets, and all WBCs except for lymphocytes
Lymphoid stem cell line of development
Pre B cells and prothymocytes finish their development into B cells and T lymphocytes in bone marrow
T cells will leave the bone marrow and migrate into some lymphatic tissue to mature
Which 3 Haemopoietic growth factors stimulate and regulate differentitation and profileration (rapid reproduction of a cell) in the various blood cells
oErythropoietin (EPO) = When the RBC numbers fall a little our kidneys will produce more EPO which will stimulate red bone marrow to produce more RBC
oThrombopoietin (TPO)
•hormone from liver stimulates platelet formation
oCytokines
•local hormones of bone marrow
•produced by some marrow cells to stimulate proliferation in other marrow cells
Red blood cells = Haematocrit/Packed cell volume (PCV)
is the percentage of blood occupied by red blood cells
2 causes of Abnormal Haematocrit
Anaemia - not enough red blood cells or not enough haemoglobin
Polycythaemia - too many RBCs
define Haemoglobin
oxygen carrying protein in cytosol - gives blood its red colour
RBC =
Haemoglobin consists of
protein consisting of 4 polypeptide chains (globin) and one haeme pigment attached to each polypeptide chain
each haeme contains an iron ion (Fe+2) that can combine reversibly with one oxygen molecule - therefore Each haemoglobin molecule is able to bind 4 oxygen molecules
Haemoglobin function
Transport gases
oxygen, carbon dioxide and nitric oxcide
Oxygen - haemoglobin molecule can carry 4 oxygen molecules from lungs to tissue cells
CO2 - haemoglobin transports 23% of total CO2 waste from tissues to lungs for release
Briefly describe recycling of Haemoglobin components (very important)
Worn out cells removed by fixed macrophages of liver or spleen
- Globin portion broken down into amino acids and recycled
- Haemeportion split into iron (Fe+3) and biliverdin (green pigment) - biliverdin converted to bilirubin (Yellow) which is secreted by liver into bile
Erythropoiesis is production of
Red blood cells
The main stimulus for Erythropoiesis ( RBC production)
hypoxia.
•From anaemia, blood loss, circulatory problems.
kidney responds to hypoxia
Process:
o Proerythroblast starts to produce Haemoglobins.
o Reticulocyte is formed.
o Reticulocytes leave bone marrow into the blood. (0.5% to 1.5% of RBC’s)
o In 1-2 days, they eject the remaining organelles to become a mature RBC.
White blood cells are also known as
Leukocytes
Structure of WBC
nucleated and do not contain haemoglobin
Surface antigens of WBC and their purpose
Major histocompatibility antigens ( MHC)
Unique for each person
Help cells to recognise each other and as belonging to you so that any cell that doesn’t have surface antigens or doesn’t have the appropriate surface antigens will be deemed foreign and will be destroyed.
WBC classification based on presence of cytoplasmic granules
Granulocytes
- Neutrophils ( most abundant)
- Eosinophils
- Basophils
Agranulocytes
- Monocytes
- Lymphocytes
WBC- Neutrophils
Granulocyte
- granules small
- 60-70% of circulating WBCs
FUNCTION:
Fastest response of all WBC to bacteria
o Direct actions against bacteria
• release lysozymes which destroy/digest bacteria
• release defensin proteins that act like antibiotics and
poke holes in bacterial cell walls destroying them
• release strong oxidants (bleach-like, strong
chemicals) that destroy bacteria
WBC - Basophils
Granulocyte
- Granules large
- Less than 1% of circulating WBC
Function:
o Involved in inflammatory and allergy reactions
o Leave capillaries and enter connective tissue as mast cells
o Release heparin, histamine and serotonin
• heighten the inflammatory response and account for hypersensitivity (allergic) reactions
WBC- Eosinophils
Granulocyte
- large granules
- 2-4% of circulating WBC
Function
o Leave capillaries to enter tissue fluid
o Release histaminase
• slows down inflammation caused by basophils
o Attack parasitic worms
o Phagocytize antibody-antigen complexes
WBC - Lymphocyte
Agranulocyte
- increase in number during viral infections
- 20-25% of circulating WBC
- categorised into 3 cell types
Functions -
o B cells
•destroy bacteria and their toxins
•turn into plasma cells that produces antibodies
o T cells
•attack viruses, fungi, transplanted organs, cancer cells and some bacteria
oNatural Killer cells
•attack many different microbes and some tumour cells
•destroy foreign invaders by direct attack
WBC - Monocyte
Agranulocyte
- The biggest of all WBC
- 3-8% of circulating WBCs
Function:
o Migrate from the blood into the tissues, enlarge and differentiate into macrophages
–fixed macrophages: Found in specific tissues
alveolar macrophages in lungs
Kupffer cells in liver
–wandering macrophages: Roam the tissues and gather at sites of infection
Take longer to get to site of infection, but arrive in larger numbers
Destroy microbes and clean up dead tissue following an infection
Leukocytosis
o a high white blood cell count
can be caused by
•microbes, strenuous exercise, anesthesia or surgery
Leukopenia
is low white blood cell count
Can be caused by
•radiation, shock or chemotherapy
Where are majority of WBC found
o Only 2% of total WBC population is in circulating blood at any given time
•rest are in lymphatic fluid, skin, lungs, lymph nodes and spleen
