Lecture 13- Composition and general functions of blood Flashcards
What are the three general functions of blood?
- Transport
- Immune Response
- Coagulation
What is the function of blood in terms of transport?
- Circulation transports substances to cells that they need to survive (O2, water, nutrients)
- It also removes waste products such as carbon dioxide
- Ions associated with pH and homeostasis
- Heat - a product of oxidative reactions in cells
- Hormones- coordinate the activities of organs of the body
- Immune cells and coagulation factors
What is the function of blood in terms of the immune response?
- For fighting infection and production of the immune response
- Largely via white blood cells
What is the function of blood in terms of coagulation?
- For preventing bleeding, they plug up the wound in the short term to prevent negative pathogens entering
- Via platelets and “coagulation factors” in plasma
What is the purpose of transporting heat in the blood?
Heat from reactions is put in the blood and transported to skin surface so that it can be removed via radiation before altering core temp.
What is blood volume in proportion to?
Lean body mass
What are the two board categories that make up the composition of blood?
- plasma
- formed elements
What is plasma?
- Liquid part of blood
- Mostly water + solid components dissolved in water.
- These solutes are generally electrolytes and plasma proteins
What is the function of Albumins?
- They are a type of plasma protein
- In charge of maintaining osmotic pressure
What are the formed elements of blood?
Formed elements are cells+ cell fragments floating the plasma:
- platelets
- white blood cells
- red blood cells
What is the function of platelets?
Cell fragments that participate in clotting to stop bleeding
What is the function of red blood cells ?
By far the most common cell found in blood; highly specialized to transport oxygen and remove waste from tissues(carbon dioxide)
What is the function of white blood cells ?
Immune response and defense mechanisms; these seek and destroy invading pathogens
Do the cells and cell fragments look the same? Considering this what is interesting?
No, they all have different structures specialized for their functions. Interesting that are all derived from the same cell (hemocytoblasts)
What is hematopoiesis?
The formation of blood cells
What are hemocytoblasts and where are they located?
- Hemocytoblasts are the progenitors for all blood cells
- Found in red bone marrow
What does erythropoietin (EPO) do?
Simulates the specific pathway for hemocytoblasts to differentiate to red blood cells.
What’s an example of when production of blood cells might increase?
After injury
What is the structure of a red blood cell like? What does this allow?
-Biconcave Disc shape (round with depression on either side)
-This means there is a large surface area: volume ratio
allowing for efficient diffusion of gases
-Flexibility for movement through narrow capillaries. Round means it doesn’t get stuck and can fold/ distend easily to fit through
What don’t red blood cells have and why?
No nucleus this because they don’t need to divide to make more red blood cells (hemocytoblasts do this)
What do red blood cells contain large amount of? What is the function of this?
- Contain large amounts of hemoglobin
- Iron is attached to heme discs to form a heme unit which binds to oxygen
- Each red blood cell has 4 of these units and so can bind 8 oxygen atoms (4 oxygen molecules)
What does a greater number of red blood cells mean in terms of a ability to carry oxygen?
More red blood cells results in more hemoglobin found inside and therefore more oxygen can be carried around
What does a centrifuge do?
Spins blood to separate into its main components:
- Plasma
- Buffy coat (white blood cells)
- Hematocrit (red blood cells)
Which layer when blood is centrifuged is the smallest?
Buffy coat, sometimes not even visible
