blood supply to spleen
blood is supplied by the trabecular artery; splits off into central arterioles which go into red pulp; wrap around white pulp (germinal center), diverge into penicillar arterioles, which lead to sheathed capillaries into either a closed circulation passing directly into splenic sinuses (S) or an open circulation, being dumped from the vasculature into the lymphoid tissue of the red pulp’s splenic cords where viable blood cells reenter the vasculature through the walls of the sinuses.
capsule (C) of the spleen
connects to trabeculae (T) extending into the pulp-like interior of the organ.
red pulp
- occupies most of the parenchyma,
- filled with blood cells of all types, located both in cords and sinuses
white pulp
- restricted to smaller areas, mainly around the central arterioles
- lymphoid tissue; large blood vessels and lymphatics enter and leave the spleen at a hilum.
5 components of red pulp
- penicillar arteries
- macrophage sheathed capillaries
- splenis sinusoids
- reticular cells
- all blood cells
ghost RBC
RBCs are phagocytized by macrophages. The only thing that is left behind is the RBC membrane
spleen and sickle cells
When sickled cells block the blood vessels leading out of the spleen, blood stays in the spleen instead of flowing through it. This causes the spleen to get bigger. When this happens the blood count (hemoglobin and hematocrit) falls and the spleen gets very large and easy to feel. This is called splenic sequestration crisis (or “spleen crisis”). Splenic sequestration can sometimes be painful
How is peripheral blood smear performed?
- place drop of blood 1cm from end of slide
- place smooth, clean end of a second slide just in front of blood drop
- hold spreader slide at 30 degrees and draw it against blood drop, allowing the blood to spread almost to the edge of the slide
- push the spread forward with light, smooth, moderate speed; should be a thin film of blood in shape of tongue.
- label with patient name, lab id, and date
- slide should be rapidly air dried by waving slides or using a fan
anisocytosis
different RBC sizes
poikilocytosis
different rbc shapes
Schistocytosis
- caused by mechanical damage–> gets sheared.
- Another cause is TTP–> intravascular hemolysis
Thrombotic thrombocytopenic purpura
-shredded RBC ○ Biliruben is high ○ Haptoglobin is low ○ LDH- high ○ DAT/coombs test (direct antiglobulin test)- negative; if it was positive, you would expect to see spherocytes because macrophages take a bite out on first pass--> spherocyte completely engulfed on second pass
Spherocytes
- due to
- next step
- negative DAT
- Round
- Due to: Hereditary spherocytosis; Autoimmune hemolytic anemia; G6PD deficiency, thalasemia
- Next step is to do a DAT (should be positive if it is autoimmune)
- If DAT is negative: Do G6PD screening to rule out/in G6PD deficiency; Do Genetic testing to see if it is hereditary (Eosin-5-maleimide)
Target cell
- looks like target; result of a change in cytosolic to membrane ratio
- Beta thalasemia
- Electrophoresis
Pencil cell
- long and skinny
- associated with iron deficiency
Howell Jolly cells
-Spleen either sick and not taking them out or the bone marrow is releasing them prematurely
hypochromic cells
- white in the middle
- caused by not having enough iron–> not enough hemoglobin synthesis–> less red)
- Iron deficient due to heavy menses
Which tests from CBC are measured directly?
- RBC count–> directly measured
- MCV–> measured direct (can also be calculated)
- Hgb and Hct usually directly measured (can be calculated depending on machine)
Which tests from CBC are measured indirectly?
- MCHC is calculated
- RDW calculated
methods used by automated instruments to count cells
impedance (counts any particle of given size), optical methods (light scatter), or combination of impedance and light scatter.
reticulocyte count
- can be measured manually or by automation.
- manual method: a blood smear is stained with a supravital dye (e.g., newmethylene blue) that highlights the endoplasmic reticulum that persists within reticulocytes. Red cells and reticulocytes are counted, and the result is given as a percentage (number of reticulocytes per 100 red cells).
- Automated methods: more accurate, since many more cells can be counted. A blood sample is incubated with a supravital dye, and then passed through an automated counter in which they are exposed to a laser. Light scatter (which will be greatest in stained reticulocytes) is used to enumerate the reticulocytes.
6 scapulohumeral muscles
Supra-spinatus Infra-spinatus Teres minor Teres major Subscapularis Delotid
Rotator cuff
Supra-spinatus
Infra-spinatus
Teres minor
Subscapularis
Empty can test
-what muscles is it testing?
assesses integrity of suprapinatus
