Lecture 19 - Blood Function and Composition Flashcards
What are the functions of blood?
- Transport
- Maintenance of homeostasis
- Defense
How is the blood involved in transportation?
- Brings nutrients to where they are needed in the body
- Transports body wastes to where they can be eliminated
- Transports hormones
What needed materials are transported in the blood?
Oxygen and nutrients
What wastes are transported through the blood?
Carbon dioxide, metabolic waste
Do single celled organisms need blood?
No, diffusion is enough (simple or facilitated). Single celled organisms can exchange directly with the environment.
What is carried in plasma?
- Waste and excess water to the kidneys for excretion
- Glucose and other nutrients from the gut to cells
- Hormones from glands to the areas that use them
- Carbon dioxide (mainly)
- White blood cells
What do red blood cells carry?
Oxygen
Where is heat carried in the blood?
In all parts of the blood.
How is the blood involved in maintaining homeostasis?
- Body temperature control
- Regulation of body tissue pH (through blood proteins and molecules acting in buffer systems)
- Regulating the water content of body cells
How is the blood involved in defense?
- Helps the body defend against infection by bacteria, viruses, and mutated cells
- Protect against injury through blood clotting
What are the components of blood?
- Fluid (plasma)
- Cells (RBC, WBC)
- Cell fragments (platelets)
What percent of the blood is plasma?
55%
What percent of the blood is the buffy coat?
<1%, includes leukocytes and platelets
What percent of the blood is erythrocytes?
45%
What is hematocrit?
The amount of RBCs as a percent of the total blood volume.
What is the normal hematocrit for (human) females?
37-48%
What is the normal hematocrit level for (human) males?
45-52%
How does hematocrit change with altitude?
The hematocrit value increases with higher altitudes.
What fraction of the body weight is blood?
8%
What is the normal blood volume for human males and females?
F: 4-5L
M: 5-6L
What is the pH of blood?
7.35 - 7.45
What is the osmolarity of blood?
280-300 mOsm/L
What is the blood viscosity relative to water?
4.5 - 5.5
What is the viscosity of plasma relative to water?
2
What is viscosity?
A measure of a fluid’s thicccccness ;) or resistance to flow.
What influences the viscosity of blood?
The presence of the plasma proteins and formed elements within the blood.
The viscosity of blood has a dramatic impact on _____.
Blood pressure and flow.
Why does hematocrit increase with higher altitudes?
To compensate for the lower oxygen pressure, the body adapts by increasing the production of red blood cells.
Why is whole blood more viscous than plasma?
Whole blood formed elements - plasma does not.
What is the temperature of blood?
38 C
Why is blood temperature higher than body temperature?
Blood experiences friction and resistance as it flows. This produces heat, accounting for the slightly higher temperature of blood.
How to calculate blood volume from weight and total blood volume in (mL/kg)?
weight x total blood volume (mL/kg) = blood volume (mL)
List from most to least abundant in blood: hemoglobin, RBC, platelet, and WBC.
- RBC
- Platelet
- WBC
- Hemoglobin
What is found in plasma?
- Water (92% of plasma)
- Proteins (albumin, globulin, fibrinogen, enzymes)
- Sugar
- Amino acid
- Lactic acid
- Lipids
- Iron
- Vitamins
- Electrolytes
What is the most abundant plasma protein?
Albumin
What does albumin do and where is it produced?
- Serves as binding and transport vehicles for fatty acids and steroid hormones. Lipids are hydrophobic; however, binding to albumin enables their transport in the water-based plasma.
- Produced in liver.
What plasma protein is the most significant contributor to blood osmotic pressure?
Albumin
What do globulins do and where are they produced?
- The alpha and beta globulins are produced in the liver, and transport iron, lipids, and the fat-soluble vitamins A, D, E, and K to the cells. Also contribute to osmotic pressure.
- The gamma globulins are proteins involved in immunity and are better known as an antibodies or immunoglobulins. They are produced by specialized leukocytes known as plasma cells.
List the plasma proteins from most to least abundant.
- Albumin
- Globulin
- Fibrinogen
What does fibrinogen do and where is it produced?
- Essential for blood clotting.
- Produced in the liver.
What is the function of electrolytes in the plasma?
- Osmotic balance
- pH buffering
- Blood clotting
- Defense
- Lipid transport
What is the function of water in plasma?
- 90% of plasma volume
- Solvent for carrying other substances
- Absorbs heat
What would cause total protein in blood to be increased?
Dehydration, inflammation.
What could cause total protein in blood to be decreased?
Bleeding, malnutrition, CHF.
What would cause albumin concentration to increase in blood?
Dehydration.
What could cause albumin concentration to decrease in blood?
Bleeding, CHF, liver failure.
What could cause globulin to increase in blood?
Infections or inflammation (present with some long-term infectious disease).
What is polycythemia?
An increased level of hematocrit.
What is anemia?
A decrease in hematocrit.
What can cause anemia?
- Blood loss
- Destruction???
- Lack of RBC production
What affects the clinical signs of anemia?
- The degree of anemia.
- Duration (acute/chronic).
- Underlying cause.
How much blood loss can cause shock or death?
More than 1/3 of blood lost in a short time.
What signs will the animal present in acute blood loss?
- Tachycardia
- Pale mucous membranes
- Bounding or weak peripheral pulses
- Hypotension
What are the signs of chronic anemia?
- Lethargy
- Weakness
- Anorexia
Why can acute anemia cause tachycardia?
Heart is working harder to compensate for reduced blood volume.
Why can acute anemia cause pale mucous membranes?
Less blood going to tissues.
Why can acute anemia cause either weak or bounding pulses?
- Depends if the body is still compensating or not.
- Depends on amount of blood loss.
