Unit 1- Molecules, Blood and Gas Exchange
Molecules and Blood
- Created by: Rebecca
- Created on: 19-09-12 10:59
Blood Tests
1. Torniquet to make the vein stand out and easy to target the needle
2. Clean area with alcohol based solution
3. Push sterile needle attached to sterile syringe
4. Cotton ball over the wound
5.Press for 1-2 mins and apply dressing
Blood Smear
1. Put small drop of blood near end of clean microscopic slide
2. Place end of slide on sample to "catch" blood
3. Hold spreader @ 30deg angle & slide to smear
4. Label slide with patients details
5. Allow slide to dry in the air so cells stick
6. Fix slides with alcohol to preserve the cells
7. Stain slide using Romanowsky Stain
8. Pour over and leave for 2 mins to be washed off w/ water
Erythrocytes
Erythrocytes
- Bi concave disks
- Large surface area- to - volume ratio to speed gas exchange
- Cytoplasm packed with haemoglobin
- Small and flexible so they can flatten against capillary wall which reduces distance and speeds gas exchange
Mature red blood cells
- No nucleus
- More room for haemoglobin
Neutrophils
Neutrophils
- Type of leucocyte
- Small granules in the cytoplasm
- Engulf microorganisms by phagocytosis
NeutRO -> ROugh granules -> phaGOcytosis
Lymphocyte
Lymphocyte
- Type of leucocyte
- Large dark nucleus
- Thin layer of clear cytoplasm
Two types of Lymphocyte
- Both are cells of the immune system
B Lymphocyte- Produces antiBodies
T Lymphocyte- Several functions including cell destruction
Monocyte
Monocyte
- Largest of the leucocytes
- Large bean shaped nucleus and clear cytoplasm
Spend 2-3 days in circulatory System
-Then move to the tissues
- Then become macrophages
- Then engulf microorganisms and other foreign material
Membranes
Cell membranes are mainly made up of two kinds of molecule:
- Phospholipids (which form the bulk of the membrane)
- Proteins (which are scattered around in the membrane)
Some molecules of carbohydrate and cholesterol may also be present
Phospholipid
- Special kind of lipid molecule
- Made of a glycerol molecule with a phosphate group and 2 fatty acid chains
Phosphate group:
- Hydrophilic (water loving) because it has a charge
- Soluble in water
Fatty acid chains:
- Made up of hydrocarbons
- Hydrophobic (water hating)
- No charge and insoluble in water
Phospholipid (2)
Phospholipids pack together in a membrane
They form a double layer called a bilayer
There is water inside and outside of a cell so:
- The fatty acid tails pack AWAY from water because they don't like water
- They hydrophilic heads arrange themselves on the outside of the membrane, facing TOWARDS the water
Proteins
- In a membrane there are different sorts of protein with complex shapes
- Proteins are scattered around the membrane and change position
Intrinsic Proteins- Large proteins span the whole bilayer
Extrinsic Proteins- Smaller proteins on just one side of the bilayer
Glycoproteins- Some proteins have carbohydrate chains attached on the outside of the cell. In the plasma membrane, these proteins are involved in cell recognition. Therefore, other molecules may attach to them, Some of the carbohydrate chains join to other carbohydrate chains in the glycoproteins of cells which are next to them.This causes the cells to join together -Cell adhesion.
Glycolipids- Sometimes carbohydrate chains attach to phospholipids
Cholesterol- Present in many membranes to keep the membrane stable.
- Lipid like substance called a steroid
The Fluid Mosaic Model of Membrane Structure
Membranes around and within cells
- The membrane separates the cell from its environment (plasma/tissue fluid) and from other cells.
- Glycoproteins are also important in cell to cell signalling
- The binding of ions or other chemicals to these receptors can trigger reactions inside the cell, including the switching on or off of genes in the nucleus
- Blocking these receptors is one way that drugs can have an effect
Membranes are also found inside cells to separate cells into 'compartments'. The membranes allow complex processes within the cell to be seperated
E.g. Enzymes involved in respiration are found in the mitochondria.
Membrane Bound Structures
Plasma Membrane
- Partially permeable. Retains cell contents
Rough Endoplasmic Reticulum
- Ribosomes synthesise proteins. Membranes package them for distribution around the cell
Smooth Endoplasmic Reticulum
- Synthesis of lipids including steroids
Golgi Apparatus
- Synthesis of glycoproteins, polysaccharides and hormones. Production of lysosomes
Nuclear Envelope
- Regulates exchange between cytoplasm and nucleus
Membrane Bound Structures- Organelles
Lysosomes
- Contain enzymes for intracellular digestion
Nucleus
- Contains DNA and regulates cell activity
Mitochondria
- Aerobic respiration and production of ATP
Chloroplast
- Absorbance of light energy and production of carbohydrates in photosynthesis
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