What are the 6 steps for taking a blood sample?
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
What are the 8 steps to creating a blood smear?
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
Haemocytometers - Red Blood Cells
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
What are the three types of leucocytes?
(Leucocyte - white blood cell)
3. Monocytes --> macrophages
- Small granules within cytoplasm
- engulf microorganisms by phagocytosis
- Large nucleus
- Thin, clear cytoplasm
B lymphocytes = antibody production
T lymphocytes = cell destruction etc.
- Large, bean-shaped nucleus
- Spend 2-3 days in the circulatory system, then become...
- 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
Size of structure in the picture is always at the top!
1. Phospholipids (form basis of membrane)
2. Proteins (scattered around membrane)
Carbohydrates and cholesterol may also be present.
Structure of Phospholipids
glyerol molecule + phosphate group + fatty acid chains = phospholipid
- Formed of the phosphate group
- Hydrophillic (water-loving)
- Charge = soluble in water
- 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.
Proteins Within Plasma Membranes
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)
Membranes In and Around Cells
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
3. Nuclear membrane
5. Nuclear pore
7. Secretory vesicles
9. Rough endoplasmic reticulum
10. Smooth endoplasmic reticulum
11. Golgi apparatus (body)
Collaboration of Organelles Within Eukaryotic Cell
To perform functions, organelles often have to work together.
Antibody production is an example of this...
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.
Comparing Animal and Plant Cells
nucleus, nucleolus, ribosomes, cell wall, plasma membrane, golgi apparatus, rough endoplasmic reticulum, smooth endoplasmic reticulum, mitochondria, chloroplasts, permanent vacuole, cytoskeleton
- 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