Formed elements
= red blood cells and platelets
[Pseudo cells]
- means they are not true cells - without nuclei
Erythrocytes (RBCs)
- Red blood cells (RBCs)
- Contain no nucleus, organelles, or ribosomes
- Structure is well suited to main function of O2
transport in blood
Structure of RBCs is well suited to main function of O2
transport in blood
- Biconcave discs
- Provides larger surface area for diffusion of O2
across the membrane
- Thinness of cell enables O2 to diffuse rapidly
between the exterior and innermost regions of the
cell - Flexible membrane
- Allows RBCs to travel through narrow capillaries
without rupturing in the process
where are red blood cells produced?
- produced in the bone marrow and released into the
bloodstream when they mature. - They contain hemoglobin, a protein that transports
oxygen throughout the body. - The typical lifespan of an RBC is 120 days. Thus, the
bone marrow must continually produce new RBCs to
replace those that age and degrade or are lost
through bleeding. - A number of conditions can affect the production of
new RBCs and/or their lifespan, in addition to those
conditions that may result in significant bleeding.
RBCs normally are uniform in size and shape, but their appearance can be affected by a variety of conditions
- such asvitamin B12, folateand iron deficiency.
- An example of a common condition affecting RBCs is
anemia, which results from low red blood cell counts and low hemoglobin. - Various diseases can lead to anemia, so additional
tests are often needed to determine the cause.
too little iron carrying capacity = anemia
too much iron carrying capacity = hemochromatosis
Hemoglobin:
found only in red blood cells
= Pigment containing iron
- Appears reddish when oxygenated
- Appears bluish when deoxygenated
Molecule consists of 2 parts
- Globin portion
Protein composed of four highly folded polypeptide chains - Heme groups
Four iron-containing nonprotein groups
Each is bound to one of the polypeptides
https://www.youtube.com/watch?v=_ZV5140OykE
Hemoglobin Structure
https://www.youtube.com/watch?v=E3g4RWB6_CM
What is hemostatic imbalances
Anemia
> Refers to a below-normal O2-carrying capacity of
the blood
Characterized by low hematocrit
SICKLE CELL ANEMIA
- Abnormal hemoglobin (change in one of the amino
acids in 2 of the 4 polypeptide chains of hemoglobin)
- Lower oxygen content
- Crescent-shaped RBCs
- Cannot flow easily
Hematocrit Under Various Conditions
What is the hematocrit?
The volume percentage of red blood cells in blood, measured as part of a blood test
What is a complete blood count (CBC) if you go to a pathologist?
https://www.youtube.com/watch?v=d0GxAtkBrgQ
Sickle cell disease
- condition in which the red blood cells are all abnormally shaped
- It is a genetic variation
- effects O2 carrying protein - hemoglobin
- tend to clump together and clot
How does Sickle cell disease help against Malaria
- Sickle Cells stick to vessel walls and lose potassium
(essential nutrient for malaria parasites) - “helps” against malaria
- Sickle cell individuals better survival chance
What is Polycythemia?
Characterized by too many circulating RBCs and elevated hematocrit
2 general types of Polycythemia
- Primary polycythemia
- Caused by tumorlike condition of bone marrow (polycythemia vera)
- Erythropoiesis proceeds at an uncontrolled rate - Secondary polycythemia
- Noral physiological response by living at high altitudes
- Dilemma: higher blood viscosity/ impaired circulation
RBC in diabetes
- Circulatory biomarkers that causes blood to become sticky as it blinds to plasma proteins
- Fibres around RBC = abnormally clotted plasma proteins
And due to high amounts of glucose, in circulation, the red blood cell membranes become fragile and causes folding into different/ strange shapes
RBC in smokers
- every puff of smoke exposes lungs to 10^18 toxins
- These toxins come into direct contact with RBC via lung bronchiole
- This causes RBCs to function abnormally and to live much shorter (typical 120 days)
- Such RBCs dont carry oxygen properly
