Lecture 13 - Blood Flashcards
Functions of blood
- > transportation of 02, CO2, metabolic waste, nutrients and hormones
- > regulation of body temp (vasodilation of surface vessels dump heat)
- > protection from disease and infection (contains cells of immune defence system)
Physical characteristics of blood
- > average blood volume is 5L in adults, maintains BP
- > thicker/more viscous than water and slightly adhesive
- > temp 37-38 degrees
- > pH = 7.4 (7.35-7.45)
- > makes up around 8% of total body weight
What does the colour of blood depend on
*depends on oxygenation status*
- > oxygen-rich blood = bright red
- > oxygen-poor blood = dark red
• appears blue in superficial veins
Components of blood
55% plasma
45% cells
- 99% of cells are RBC
- less than 1% are WBC and platelets
Components of plasma
- > over 90% water
- > 7% of plasma is made up of proteins which are created in liver, confined to bloodstream
- > 3% other substances; waste electrolytes etc.
What are the plasma proteins
- > albumins (58%)
- > globulins (37%)
- > fibrinogens (4%)
- > 1-2 % other substances
- electrolytes (Na, Cl ions)
- Nutrients and vitamines
- hormones and waste products
What are albumins
- > smallest and most abundant plasma protein (makes up 58% of total plasma proteins)
- > helps maintain a constant blood volume and pressure
- > act as transport proteins (carry ions, hormones, some lipides)
What are globulins
- > second largest group of plasma proteins (makes up 37%)
- > smaller alpha-globulins and larger beta-globulins transport some water-insoluble molecules, hormones, metals and ions
- > gamma-globulins are also called immunoglobulins (or antibodies) and play a part in body’s defenses
What are fibrinogens
- > make up 4% of total plasma proteins
- > contributes to blood clot formation
- > following trauma, soluble fibrinogen is biochemically converted to insoluble fibrin strands
- > plasma with clotting proteins removed is called serum
What are the formed elements of blood
- > erythrocytes
- > leukocytes
* granular leukocytes
* agranular leukocytes
- > platelets (special cell fragments)
Normal reproduction rate and lifespan of RBC
- > 2 million RBC/second enter circulation from red bone marrow
- > Live roughly 120 days (no repairs, no organelles)
- > worn out cells are removed by microphages in spleen and liver
PHYSICAL Characteristics of Erythrocytes
- > biconcave disk (increases surface area/volume ratio and this flexible shape allows transport through narrow passages)
- > no nucleus or organelles
Hemoglobin (Hb)
- > oxygen carrying protein that gives blood its colour and makes up 1/3 of RBC weight
STRUCTURAL characteristics of hemoglobin
- > globin protein consists of 4 polypeptide chains
- > one heme attached to each peptide chain
- > each heme contains an iron iron (centre) that can combine reversibily with one oxygen molecule
Oxyhemoglobin vs Deoxyhemoglobin
Hb + oxygen = oxyhemoglobin
Hb - oxygen = Deoxyhemoglobin
How does Hb transport 02 and C)2
- > each hemoglobin molecule can carry 4 oxygen molecules from lungs to tissue cells
- > hemoglobins transports 23% of total CO2 waste from tissue cells to lungs for release (combines with amino acids in globin portion of Hb; CO2 also travels dissolved in blood plasma)
How do erythrocyte antigens relate to their blood type
*Presence/ absence of surface antigens determines ABO blood type*
Type A - > erythrocyte with surface antigen A
Type B - > erythrocytes with surface antigen B
Type AB - > erythrocyte with both antigens
Type O - > erythrocytes with neither antigen
How do plasma antibodies determine blood type
Surface antigens accompanied by specific plasma antibodies:
Type A - > blood has anti-B antibodies in the plasma
Type B - > blood has anti-A antibodies in the plasma
Type AB - > blood has neither antibodies in the plasma
Type O - > blood has both antibodies in the plas
Granular vs agranular clasification of WBC
based off the presence of cutoplasmic granules made visible by staining
Granulocytes - > neutrophils, eosinophils or basophils
Agranulocytes - > monocytes or lymphocytes
Neutrophils
- > makes up 50-70% of leukocytes
- > polymorphonuclear leukocytes (PMNs); type
- > Nuclei: 2-5 lobes connected by thin strands
- > function: enters tissue spaces to phagocytize pathogens
Eosinophils
- > makes up 1-4% of WBC
- > nucleus: 2 lobes
- > large, uniform-sized granules
- > granules contain enzymes that end allergic reactions (antigen-antibody complexes)
- > active in fighting parasitic worm infection
Basophils
- > make up less than 1% of leukocytes
- > irregular, multi-lobed nuclei
- > secretes histamine and heparin
Lymphocyte
- > makes up 20-40%
- > no granules, large nucleus + some cytoplasm
- > resides in lymphatic tissues (thymus,lymph glands)
- > T cells manage immune response
- > B cells become plasma cells and secrete antibodies
- > NK cells attack abnormal and infected cells
Monocytes
- > Make up 2-8% of leukocytes
- > nucleus is shaped like a C or kidney bean
- > largest WBC in circulating blood
- > transform into large phagocytic cells, macropahges
- > phagocytize bacteria, viruses, debris
Emigration & Phagocytosis in WBC
- > WBC roll along endothelium, stick to it and sqeeze between cells:
- adhesion molecules (selectins) near ingury site help WBCs stick to endothelium
- molecules (intergrins) found on neutrophils assist in movement through wall
- > Neutrophils & macrophages will phagocytize bacteria and debris
Platelet Anatomy
*thrombocyte*
- > formed from large cells called megakaryocytes
- > circulates for 8-10 days
Explain the steps of hemostasis
