Lecture 13: Composition and General Function of Blood Flashcards
What are the 3 general functions of blood?
- Transport
- Immune response
- Coagulation
What are examples of things transported by blood?
5
- Nutrients
- Waste products
- Heat
- Hormones
- Immune cell/coagulation factors
How is blood used for immune response?
Fighting infection and production of the immune response
What type of cell is the immune response largely coordinated by?
White blood cells
Why is blood needed for coagulation?
To prevent bleeding
How does blood help to prevent bleeding?
Via platelets and coagulation factors in plasma
What makes up the majority of plasma?
Water
What components make up plasma?
3
- Proteins
- Other solutes
- Water
What is the role of Albumins in plasma?
Maintain osmotic pressure
What is the role of Globulins in plasma?
Immune response
What is the role of Fibrinogen in plasma?
Coagulation factor
What is the role of enzymes and hormones in plasma?
Lots of functions; varies by person
What are the 3 main formed elements of blood?
- Platelets
- White blood cells
- Red blood cells
What is the role of platelets in blood?
Cell fragments that participate in clotting to stop bleeding
What is the role of white blood cells in blood?
Immune response and defence mechanisms; these seek and destroy invading pathogens
What is the role of red blood cells?
Highly specialised to transport oxygen, most common cell found in blood
What is Hematopoiesis?
The formation of blood cells
Where is Hematopoiesis initiated?
In red bone marrow, which contains hemocytoblasts
What are Hemocytoblasts?
The progenitors for all blood cells
What does Erythropoietin (EPO) do?
Stimulates myeloid stem cells to form towards red blood cells (Erythropoiesis)
What is the shape of red blood cells?
Biconcave discs
What are 3 features of red blood cells because of a biconcave disc shape?
- Large surface area:volume ratio
- Allows for efficient diffusion of gases
- Flexibility for movement through narrow capillaries
What makes up approximately 1/3 of the weight in RBC’s?
Hemoglobin
What does Haemoglobin use as a part of the heme structure to bind oxygen?
Iron
How many oxygen molecules can haemoglobin bind too?
4 molecules, 1 molecule per heme
What is the fraction of blood occupied by the red cells called?
Haematocrit or packed cell volume (PCV)
What is the fraction of blood occupied by the white blood cells and platelets called?
Buffy coat
What is it called when the fraction of red blood cells is too low in a centrifuged blood sample?
Anemic
What is it called when the fraction of red blood cells is too high in a centrifuged blood sample?
Polycythemic
What is red blood cell production stimulated by?
Erythropoietin (EPO)
Where is EPO produced?
The kidneys
What is a decrease in oxygen delivery sensed by?
The kidneys
As a response to low oxygen delivery what do the kidneys do?
Release EPO
Where does EPO make its way too, to stimulate red blood cell production?
Red bone marrow
What is Erythropoiesis augmented by?
Testosterone
What is the normal Haematocrit or PCV for men?
0.4 - 0.54
What is the normal Haematocrit or PCV for women?
0.37 - 0.47
