Chp 25- Blood

Chp 25- Blood

1. plasma

   • liquid part of blood
     • pale golden liquid
   • makes up 55% blood
   • made of
     • 90% water
     • 7% proteins
       • antibodies
         • produced by white blood cells
         • combine and neutralise foreign substances
       • clotting proteins
         • form blood clots when cells/tissues become damaged / bruised
     • 3% dissolved materials
       • glucose
       • salts
       • minerals
       • amino acids
       • vitamins
       • carbon dioxide
       • urea
       • hormones
   • role
     • To transport dissolved materials such as...and to carry heat
   • Serum
     • plasma from which the clotting proteins have been removed
     • blood cannot coagulate / clot therefore can be stored in blood banks

2. Red blood cells

   • also called corpuscles or erythrocytes
     • produced in bone marrow
       • all active (child)
       • active in adult
         • sternum
         • ribs
         • vertebrate
   • round and small
     • 5 million per cubic millimetre
     • flexible membrane containing haemoglobin
     • broken down and replaced at rate of 3 million cells per second
     • live for four months
       • dead red blood cells broken down in liver and spleen
         • iron from haemoglobin stored in the liver and may be recycled to make new haemoglobin in the bone marrow
   • role
     • TRANSPORT OXYGEN
     • haemoglobin based on molecules of iron
       • can join with oxygen in areas of high oxygen concentration
         • release oxygen in areas of low oxygen concentration
           • bonds by means of weak covalent bonds
             • loose chemical union
   • more detail
     • no nuclei (when mature)
       • first made they have a nucleus
         • lose it after a few days
           • then called corpuscles
     • no mitochondria
       • no energy supply
     • biconcave shape
       • gives larger surface area over which they can exchange oxygen

3. white blood cells

   • larger than red blood cells
   • no definite shape
   • have a nucleus
   • live for few days (some live for years ie phagocytes)
   • less numerous than red 700 red: 1 white
   • ROLE
     • defend body against infection
     • majority- phagocytes
       • attack bacteria
         • engulf bacteria and digest them
           • phagocytosis
     • some-lymphocytes
       • react to invading particles by producing antibodies
         • defend against infection
           • antibodies are highly specific proteins that recognise just one pathogen
   • TYPES
     • lymphocytes
       • made in bone marrow
       • some mature in lymphatic tissue
       • later stored in parts of lymphatic system
         • spleen
         • lymh nodes
         • tonsils
       • 25% of all white blood cells
       • survive 3 months-10 years
       • function
         • make antibodies
     • monocytes
       • formed in bone marrow
       • 5% of white blood cells
       • 6-9 days
       • kidney or lobed shaped nuclei
       • function
         • scavenge through body and find and digest bacteria
           • also called macrophages
             • means large phagocyte

4. platelets

   • also called thrombocytes
   • made in bone marrow from large cells
     • break down to produce cell fragments called platelets
   • smaller than a red blood cell
   • role
     • clot the blood
       • when tissue is damaged a complex clotting process is triggered
         • makes a soluble protein called fibroingen change to insoluble protein called fibrin
     • clot results when damaged body cells produce chemicals that stimulate platelets to form a clot
     • Two main functions of blood clots
       • reduce the loss of blood
       • prevent entry of micro-organisms by sealing a wound by forming a scab
   • haemophiliacs
     • unable to produce one or more of the 20 clotting chemicals
       • cannot clot blood

5. Blood

   • functions
     • transport food waste products and hormones (plasma)
     • transport oxygen (red blood cells)
     • defense against disease due to...
   • blood groups
     • A
       • antigen A and antibody b
         • receive from A and O
     • B
       • has antigen B and antibody a
         • receive from B and O
     • AB
       • has antigen AB but no antibody
         • can receive from all
     • O
       • no antigens but has both antibodies
         • receive only from O
     • Rhesus Factor
       • 85% Irish people have the rhesus factor
         • rhesus positive
       • 15% rhesus negative