Unit 1 - The Blood (Midterm #1) Flashcards
What are the 5 functions of blood?
- Transport (gases, nutrients, wastes, etc)
- Stabilizing pH and electrolyte composition
- Restricting fluid loss (through clotting)
- Defending body against toxins and pathogens (WBCs)
- Stabilizing body temperature
Does blood have a higher or lower viscosity than water?
Higher viscosity than water
- it is thicker, moves more slowly
What is the main determinant for blood viscosity?
The number of red blood cells in the blood
What happens if the blood has a high osmolarity?
Big dissolved particles in the blood cannot leave the blood vessel, fluid will flow INTO the blood vessels to try to dilute the blood concentration.
- Results in high blood pressure
What happens if the blood has a low osmolarity?
Big dissolved particles in the blood cannot leave the blood vessel, fluid will flow OUT of the blood vessels to try to dilute the interstitial spaces and into the tissues
- Results in low blood pressure
What could result if there is a significant drop in blood osmolarity?
Edema!
- fluid enters the tissues, results in swelling
Define Hypovolemia.
Low blood volume
(
Define Normovolemia.
Normal blood volume
4 - 6 litres
Define Hypervolemia.
Excessive blood volume
> 6 litres
What happens to blood pressure if the patient is hypovolemic? Hypervolemic?
Hypovolemic = low blood pressure (excess loss of fluid), tissues might not be well perfused Hypervolemic = high blood pressure (too much fluid)
Why might a patient have more or less blood than is considered “normal”?
Blood volume varies with body weight
- a large patient will have a higher blood volume
- a small patient will have a smaller blood volume
What are the formed elements of blood?
- Cells
2. Cell fragments
What does plasma consist of?
- Water
- Electrolytes
- Proteins
- Other dissolved and suspended particles
What is the ratio of whole blood to plasma?
Approx 55% plasma
Approx 45% whole blood
What makes up 92% of plasma?
Water!
How is blood plasma different from interstitial fluid?
- It has a higher amount of dissolved oxygen in it
- It has a large number of dissolved proteins in it
How is the ration of whole blood:plasma different in men and women?
Men have less plasma relative to whole blood (higher oxygen carrying capacity)
Women have more plasma relative to whole blood
Why are pH changes in plasma lower than in interstitial fluid?
Because of the buffering capability of the proteins in the blood
What are the 4 different kinds of proteins found in the blood plasma?
- Albumins
- Globulins
- Fibrinogen
- Regulatory proteins
What is the most prevalent protein found in blood plasma?
Albumins (60%)
- Globulins (35%)
- Fibrinogen (4%)
What is the function of Albumins?
- Contributes to oncotic pressure (ability to draw water INTO the bloodstream)
- Attaches to lipids to form lipoproteins
What is the function of Globulins?
Immunoglobulins attack foreign proteins
What is the function of Fibrinogen?
Important in blood clotting
What is leftover if you remove fibrinogen from plasma?
Serum
What does hematocrit (hct) measure?
Percentage of whole blood (RBCs + plasma) occupied by cellular components
- closely approximates volume of RBCs
What is the ratio of RBCs to WBCs?
1000 RBC to 1 WBC
Do men or women typically have a higher hematocrit?
Men!
- more RBC in circulation
- higher oxygen carrying capacity
Why should athletes train at high altitudes?
- Air pressure is lower, amount of available oxygen is lower
- The body produces more RBCs to compensate of the low levels of oxygen
- When athletes come down to sea level to compete, they have very high level of hematocrit = high oxygen carrying capacity
= higher performace
What is the function of RBCs?
Transport oxygen and carbon dioxide (in cytoplasm of RBCs)
What is the importance of the biconcave disc of RBCs?
- Provides a large surface area compared to volume ratio
- The higher the surface area, the higher the binding ability of oxygen to the cell
What are the main structural properties of RBCs?
- Lack mitochondria, ribosomes, and nuclei
- Unable to perform normal maintenance
- Degenerate after approx. 120 days
- Recycled by phagocytes
What is the most prevalent RBC protein?
Hemoglobin (95% of RBC proteins)
- 5% of RBC proteins are enzymes involved in the binding of hemoglobin
What is the function of hemoglobin?
Gives the RBC the ability to transport oxygen
What is hemoglobin composed of?
- Two alpha chains
- Two beta chains
- Each chain holds 1 Fe+2 heme group
How many oxygen molecules can 1 hemoglobin molecule hold?
4!
- 1 oxygen molecule binds to each Fe+2 molecule in each chain
Why is the O2 sat on patients not 100%?
Each chain of the hemoglobin doesn’t ALWAYS bind optimally (all 4 sites are occupied)
- Sometimes only 1, 2, or 3 sites are occupied
What parts of hemoglobin are recycled? What parts are destroyed?
- Alpha and beta chains AND Fe+2 are recycled
- Heme portion is destroyed
Where are most RBCs destroyed?
In the capillaries of the spleen
What gives feces and urine their color?
Bilirubin!
- result of RBCs being destroyed.
Describe the steps involved in the process of how RBCs are broken down.
- Macrophages in the spleen destroy the RBC
- Amino acids and Fe+2 are recycled
- Heme is broken down into bilirubin
- Liver detoxifies bilirubin –> conjugated bilirubin
- Excreted in feces or urine
What is the difference between unconjugated and conjugated bilirubin?
- UNconjugated bilirubin = toxic b/c it is insoluable; produced by WBC (macrophage) and CANNOT be excreted! = Jaundice
- Conjugated bilirubin = soluable; able to be excreted by the kidneys
What are the two fates for unconjugated bilirubin?
- Liver converts to conjugated bilirubin –> bile
2. Too much unconjugated bilirubin in the blood –> Jaundice
What are the two reasons that jaundice can occur?
- Destruction of RBCs is happening too quickly/too much
2. Something is wrong with the liver (not converting unconjugated –> conjugated bilirubin