Blood

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Functions of blood

  • Acts as a transport fluid carrying many substances to various parts of the body
  • Blood is vital for maintaing homeostatis throughout the body.

Composition of blood 

  • Blood is a type of cennective tissur consisting of liquid matrix containing cells and cells fragments/ 
  • Plasma is the liquid matrix, and the formed elements are the cells and cells fragments. 
  • Plasma makes up 55% of the total blood volume, formed elements make up 45%
  • Total blood volume in the average female is 4-5 L
  • Total blood voluem in the average adult male is 5-6 L
  • Blood makes up 8% of the total weight of body. 

Plasma 

  • Plasma is the liquid matrix of the blood
  • Pale yellow fluid that consists of 91% water and 9% other substances, such as proteins, ions, nutrientsm gases, waste productsand regulatory substances. 

Formed elements 

  • consist of cells and cell fragments 
  • Cells include red blood cells and white blood cells
  • Cell fragments are more commly called platelts
  • Formed elements make up 45% of total blood volume. 

Functions 

  • Primarly function of red blood cells are tpo transport 02 from the lungs to the various body tissue and transport 02 from the tissue to the lungs. 
  • About 98.5% of the 02 in the blood is tranpsorted to combination with the hemoglobin in the red blood cells. 
  • Remaining 1%% is diddolved in the plasma. 

White blood cells 

  • Grouped into two catergories based on their apperance in stained preperations. 1) granulocytes and 2) agranulocytes. 
  • Granulocytes are wgite blood cells with large cytoplasmic granules and lobed nuclei
  • Granules stain with dye that makes the cells more visible when viewed through a light microscope. 
  • Neutrophils (stained with acidic and basic dyes)
  • Eosinophils (stained red with acidic dyes)
  • Basophils (stained dark purple with basic dyes
  • Agranulocytes are white blood cells that appear to have no granules when viewed with a light microscope
  • Agranulocytes have granules, but are so small that they cannot be seen easily
  • The two types of granules are - lymphocytes and monocytes
  • They have a nuclei that are not lobed. 

Hemostatis

  • The cessation of bleeding is very important to the maintance of homeostatis 
  • If not stopped, execcive bleeding can result in a positive feedback cycle. 
  • Consists of ever-decresing blood voluime and blood pressure that distrups homeostatis and result in death 

Vascular spasm 

  • Immediate but temporay construction of blood vessel
  • Occurs when a smooth msucle within the wall of the vessel contracts 
  • Construction can close small vessles completley and stop the flow of bloof through them 
  • Damage to blood vessels can activate nervous system reflexes, cause spasms. 
  • Chemicals released by cells of the damaged vessels as well as plates alsop stimulate spasms.
  • Endothelial cells release the peptide endothelin, leads to contriction of blood vessels. 
  • During formation…

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