Hematology Physio Flashcards
What are the components of blood
- plasma (55%)
- formed elements (erythrocytes (45%), leukocytes, platelets (1%))
What is the normal pH range of our blood
7.35-7.45
What is the average blood volume of adult males and females
Male: 5-6L
Female: 4-5L
Describe the functions of blood
- Distribution (O2, nutrients, waste, hormones)
- Regulation (temp, pH, fluid)
- Protection (blood loss, infection)
What are the components of plasma
- 90% water
- proteins mostly produced by the liver (albumin, globulin, fibrinogen)
- clotting factors
- hormones
- respiratory gases & electrolytes
- nutrients
What is the normal albumin-globulin ration
4:2
Does serum contain clotting factors?
No, clotting factors are found only in plasma
What cell gives rise to all formed elements of our blood?
Multipotential hematopoietic stem cell (hemocytoblast)
What are the two types of cells that differentiate from hemocytoblasts
common myeloid progenitor
common lymphoid progenitor
(these branch farther into many cells, leukemias will affect one line or the other)
Define erythrocytes
- biconcave discs
- anucleate
- no organelles (anaerobic ATP production)
- contains spectrin
What is the purpose of spectrin in erythrocyte plasma membranes
provides flexibility to change shape as needed
(deficiency leads to a type of anemia)
Describe the structure of hemoglobin
- protein globin: 2 alpha & 2 beta chains (adults, 2 gamma in fetal)
- heme pigment bonded to globin
- iron atom in each heme (can bind 4 O2)
What is a reticulocyte
a mature form of a red blood cell that is not yet an erythrocyte
(formed during erythropoiesis after nucleus is ejected)
Where does erythropoiesis occur
red bone marrow
What is a scenario in which reticulocyte count would be low
aplastic anemia
What regulates erythropoiesis
Hormones
- erythropoietin
- testosterone
Nutrients
- amino acids, lipids, carbs
- iron
- vit B12
What is iron stored in the cells as and what is it transferred by
Storage: ferritin & hemosiderin
Transport: transferrin
What is the lifespan of a RBC
100-120 days
(then destroyed by macrophages in the spleen)
(Hgb A1C measures this)
What happens after a RBC is broken down
- iron salvaged for reuse
- heme degraded to yellow pigment unconjugated bilirubin, which gets conjugated in the liver, excreted as stercobilin & urobilinogen
- globin metabolized into amino acids
Define anemia
- blood has abnormally low O2 carrying capacity
- sign, not disease
- fatigue, pallor, SOB, chills
What kinds of anemia are caused by insufficient erythrocytes
- hemorrhagic
- hemolytic (RBCs destroyed)
- aplastic (Bone marrow destroyed)
What kinds of anemia are caused by low Hgb
- iron deficiency (secondary to hemorrhage, impaired iron absorption
- pernicious (Vit B12 deficiency, lack of intrinsic factor for absorption)
What kinds of anemia are caused by abnormal Hgb
- thalassemia (absent/faulty globin, think delicate RBC)
- sickle cell (gene code, low in oxygen)
When does sickling happen in sickle cell anemia
When oxygen dissociates from the heme (especially during high O2 demand like exercise)
Define polycythemia
excess of RBCs that increase blood viscosity
- bone marrow cancer, O2 loss, blood doping
What process allows WBC to leave capillaries
diapedesis