Function of blood

to maintain homeostasis

Characteristics

Blood always circulates throughout our bodies, through veins and arteries, in order to provide the body with oxygen, nutrition, and waster removal. Blood is mostly liquid with a lot of cells and proteins in it.

Blood consists of four parts

  • Red Blood Cells
  • White Blood Cells
  • Platelets
  • Plasma
The average amount of blood in a normal persons body is about 5 liters

How blood is made

Blood cells are made in bone marrow. In kids most of the marrow in the bones produces blood, but in adults only certain marrow continues to produce blood. Red bone marrow actively produces blood and yellow bone marrow no longer produces blood.


All blood cells come from the same kind of stem cell and can potentially turn into any kind of blood cell.

Red Blood Cells

Percentage

  • about 40-45% of bloods volume in red blood cells

Characteristics

  • no nucleus
  • enorumus total surface area because of their unique shape.

Function

  • Main function is to transport oxygen and carbon dioxide

What do they look like?

  • "caved in" on both sides so that the center is thin and the edges are thicker,
  • no nucleus in these cells

Vocabulary

  • Erythrocyte- another name for red blood cells, deliver oxygen to tissues and return carbon dioxide to the lungs. Released from bone marrow with a life span of 120 days.
  • Hemoglobin- a protein in the red blood cells that carries oxygen
  • Oxyhemoglobin- Carries the pigment of the red blood cells that give them the red color and shows that there is oxygen in the blood.
  • Carbaminohemoglobin- A combination of carbon dioxide and hemoglobin in the blood, shows that carbon dioxide exists in the blood.

White Blood Cells

Percentage



  • only about 1% of blood is white blood cells in a healthy person



Characteristics


  • Granular white blood cells include:
  1. Neutrophils (50-70%)
  2. Eosinophils (1-4%)
  3. Basophils (less than 1%)
  • Agranular (or non-granular) white blood cells inclue:
  1. Lymphocytes (25-40%)
  2. Monocytes (2-8%)


Function


  • Defend the body from cancer cells that form inside our tissues and from microorganisms that have succeeded in invading our bodies.


What do they look like?


  • irregular in shape


Vocabulary


  • Leukocytes- white blood cell
  • Neutrophils- Most abundant type of WBC and is an essential part of the innate immune system. Eat bacteria.
  • Eosinophils- white blood cell that combats parasites and certain infections they also control mechanisms often associated with allergies and asthma.
  • Basophils- Least common type of WBC. Produce histamine and heparin.
  • Lymphocytes- type of white blood cell that protect against infection, they are not phagocytic. T cells directly attack viral infected or cancerous cells and B cells make antibodies that attack particular viruses, bacteria, or chemical toxins..
  • Monocytes- a phagocyte that turns into a macrophage.
  • Macrophage- phagocyte cells in the immune system
  • Granulocyte- A category of white blood cells characterized by the presence of granules in their cytoplasm.
  • Agranulocyte- white blood cells without cytoplasmic granules

Platelets

Percentage



  • only a small percentage of the blood is platelets



Characteristics


  • smallest of three main blood types
  • contain proteins that allow the shape to change
  • average life span is 5-9 days


Function


  • play an essential role in blood clotting and prevention of bleeding


What do they look like?


  • not true cells but circulating fragments of cells
  • changes shape


Vocabulary


  • Thrombocytes-another name for platelets
  • Prothrombin activator- a protein formed by clotting factors from damaged tissue cells and platelets. Converts prothormbin into thrombin, an essential step in blood clotting.
  • Thrombin- protein important in blood clotting
  • Fibrinogen- soluble blood protein that is converted to insoluble fibrin during clotting.
  • Fibrin- insoluble protein in clotted blood
  • Coagulation- the process by which blood forms clots
  • Thrombus- stationary blood clot
  • Thrombosis- formation of a clot in a blood vessel
  • Embolus- a blood clot or other substance that is moving in the blood that may block a blood vessel.
  • Embolism-obstruction of a blood vessel by foreign matter carried in the blood stream

Plasma

Percentage


  • 55% of blood is plasma


Characteristics


  • pale yellow
  • mostly water
  • some disolved proteins


Function




  • transportation of blood cells throughout the body along with nutrients, waste products, anti bodies, clotting proteins, hormones, and proteins that help maintain the body's fluid balance.




What do they look like?


  • liquid component of blood


Vocabulary


  • Plasma protein- Proteins found in the blood plasma, the clear, protein-rich fluid which is left behind when platelets, red blood cells, and white blood cells are removed from the blood.
  • Serum- the blood plasma with the fibrinogens removed, it includes all proteins not used in blood clotting.
  • Albumins- Consists of all proteins that are water-soluble, unique from other blood proteins in that they are not glycosylated.
  • Globulins- Proteins that have higher molecular weights and water solubility values than the albumins.
  • Fibrinogen- This protein helps stop bleeding by helping blood clots to form.
  • Prothrombin- A plasma protein produced in the liver in the presence of vitamin K converted into thrombin in the clotting of blood.

How does blood clot?

A clot plugs up torn or cut vessels and stops bleeding that otherwise might be fatal.

  1. Damage has to be done to the blood vessel so that there is a rough spot in the lining of the blood vessel.
  2. Almost immediately after, damaged tissue cells in the injured vessel wall release certain clotting factors into the plasma.
  3. The factors then rapidly react with other factors already present in the plasma which then forms prothrombin activator.
  4. At the same time the platelets become "sticky" where the injury occurred and soon accumulate near the opening in the broken blood vessel, forming a soft, temporary platelet plug.
  5. As more and more platelets are present they release more clotting factors and if the normal amount of blood calcium is present the prothrombin activator triggers the next step.
  6. prothrombin is converted into thrombin
  7. Thrombin reacts with fibrinogen to change into fibrin
  8. This mesh work is the blood clot that forms a more long-term seal of the damaged blood vessel.