The Blood

1. Apply a torniquet

2. Clean the area with an alcohol-based solution

3. Push a sterile needle into the vein

4. Pull back the syringe attatched to the needle to withdraw blood

5. Remove and hold cotton wool on the wound for 2 minutes

6. Apply dressing

1. Apply a small drop onto the end of the microscope slide

2. Put the 'spreader' on top

3. At an angle of 30 degrees, scrape the spreader along to create a smear

4. Label the slide with the patient's details

5. Allow the slide to air dry, causing the cells to stick to it

6. Preserve the cells by adding alcohol to the slide

7. Stain the slide using a Romanowsky stain or a Leishman's stain

8. Leave for 2 minutes and then wash off

A counting chamber for blood cells.

Can be used to count both red and white blood cells, but they have to be diluted first.

RED BLOOD CELLS

• Diluted using blood pipette

1. fill pipette to 0.5 mark

2. draw 'Dacie's fluid' into the pipette up to the 101 mark

A bulge within the pipette contains a bead which shows the blood and Dacie's fluid have mixed together = 1 in 200 dilution.

THE DILUTED BLOOD CAN BE PLACED ON THE HAEMOCYTOMETER; RED BLOOD CELLS COUNTED IN THE TRIPLE-LINED SQUARES.

THE NORTHWEST RULE IS APPLIED.

This states that if a cell lies on the middle of north or west lines, it is counted BUT when on the middle of south or east lines they are not counted.

• RED BLOOD CELLS
  

• Carry oxygen and carbon dioxide
  

• Haemoglobin - protein that associates reversibly with oxygen

• Bioconcave shape = more oxygen carriage

• No nucleus within mature erythrocytes = more oxygen carriage 

• Small and flexible = flattened against capillary walls = smaller distance for diffusion = faster gas exchange

(Leucocyte - white blood cell)

1. Neutrophils

2. Lymphocytes

3. Monocytes --> macrophages

• Small granules within cytoplasm

• engulf microorganisms by phagocytosis

• Large nucleus
• Thin, clear cytoplasm

2 TYPES

B lymphocytes = antibody production

T lymphocytes = cell destruction etc.

• Large, bean-shaped nucleus
• Spend 2-3 days in the circulatory system, then become...

MACROPHAGES

• Engulf microorganisms

As well as erythrocytes and leucocytes, there are platelets.

These are fragments of megakaryocytes - giant cells.

Platelets are involved in blood clotting.

WHEN CALCULATING MAGNIFICATION

size of structure in the picture

real size of structure

WHEN CALCULATING REAL SIZE

size of the structure in the picture

magnification

Size of structure in the picture is always at the top!

FORMED OF:

1. Phospholipids (form basis of membrane)

2. Proteins (scattered around membrane)

Carbohydrates and cholesterol may also be present.

glyerol molecule + phosphate group + fatty acid chains = phospholipid

THE HEAD

• Formed of the phosphate group
• Hydrophillic (water-loving)
• Charge = soluble in water

THE TAILS

• Formed of the fatty acid chains
• Hydrophobic (water-hating)
• No charge = insoluble in water
• Phospholipids pack together to form a phospolipid bilayer, with the hydrophilic heads facing the water and the hydrophobic tails facing away from the water.

2 FORMS

1. Intrinsic = in the whole of the bilayer

2. Extrinsic = on one side of the bilayer only

GLYCOPROTEIN = carbohydrate chain + protein

• Involved in cell recognition
• other molcules join to glycroproteins because of this
• involved in cell-to-cell signalling
• involved in cell adhesion

GLYCOLIPID = carbohydrate chain + glycolipid

(glyco = carbohydrate chain)

AT THE SURFACE

• membranes help to separate a cell from its surroundings - like plasma or tissue fluid

WITHIN THE CELL

• Provide 'compartments' allowing complex processes within the cell to be separated

Eukaryotic = true nucleus 

ORGANELLES OF THE ULTRASTRUCTURE OF A TYPICAL EUKARYOTIC CELL:

1. Cell surface membrane

2. Cytoplasm

3. Nuclear membrane

4. Nucleolus

5. Nuclear pore

6. Mitochondrion

7. Secretory vesicles

8. Vesicle

9. Rough endoplasmic reticulum

10. Smooth endoplasmic reticulum

11. Golgi apparatus (body)

To perform functions, organelles often have to work together.

Antibody production is an example of this...

INVOLVING:

Nucleus holds gene that codes for protein on chromosomes --> messenger molecule takes code to ribosome on rough endoplasmic reticulum --> proteins made --> transported to golgi apparatus in small sacks called vesicles --> proteins are modified and repackaged --> make their way to the cell surface membrane

THE ENERGY ENABLING ALL OF THIS TO OCCUR IS PRODUCED BY THE MITOCHONDRIA (ATP)

This process involved 7 different organelles.

ORGANELLES:

nucleus, nucleolus, ribosomes, cell wall, plasma membrane, golgi apparatus, rough endoplasmic reticulum, smooth endoplasmic reticulum, mitochondria, chloroplasts, permanent vacuole, cytoskeleton

OF THESE:

• All are present in plant cells

although chloroplasts are only present in the cells of leaves or of green parts of the plant

• cell walls, chloroplasts and a permanent vacuole are not present in animal cells

the other organelles are