Human biology 1.1.1 the blood

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Suggest why blood films are very thin,clean and gr

So cells can be distinguished from each other under a microscope

clean and grease free so cells stick to the slide

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Why is a stain used?

Makes some structures appear darker or different colour

stains nuclei of leucocytes purple so that structures within blood cells show up more clearly-determined by nuclei shape as to whether its a monocyte,lymphocyte or neutrophils

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Whys sterile equipment and alcohol based solution

sterile equipment- to stop pathogens/bacteria being introduced into the body

skin cleaned to make sure no pathogens/bacteria on the the skin can enter wound causing infection

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Why are blood tests taken from the vein?

vein has less pressure so less bleeding afterwards

vein has a thinner wall so easy to insert the needle

wider and nearer to the surface

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outline making and staining a blood film?

add small drop of blood near end of microscope slife

use end of another slide postioned at 30 degrees to smear blood along slide

label slide with paitents details, allow to dry for few minutes so cell stick

fix using alcohol to perserve the cells

add leishmans stain all over the slide and leave for 2 minutes

then wash off with water

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Outline a blood test

tie tourniquets around paitents around so vein sticks out

clean area around vein with alcohol based solution

insert sterile needle into vein which is attached to sterile syringe

pull plunger of syringe until right amount of blood has entered the syringe

remove the needle and place cotton wool and pressure for 2 minutes until bleeding stops

apply dressing

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Describe the use of haemocytometer?

designed to count eythrocytes

add dilution factor 1 in 200

count all cells following north-west rule

3 or more counts in different squares

calculate a mean

1/0.2 x E x200 = E x 10000

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Why is a dilution factor used?

causes red blood cells to burst so leucocytes are more visble as less leucocytes than eythrocytes

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Describe structure and function of Erythrocyte?

structure: biconcave discs

             no nucleus or organelles- flattened


Function: transport 02 from lungs to tissues and CO2 from tissues to lungs.

does this as its shape means it has a large surface area to volume ratio so more gas exchange can occur between interior cells and surrounding plasma

small and flexible be able to squeeze through capilarries therefore reducing distances for gases to diffuse across

lots of room for haemoglobin which associates reversibly with o2 so more o2 can be carried

other facts: life duration 120 days spleen is where they are destroyed

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What is the structure and function of neutrophil?

granular ctyoplasm where nuclues is separated into several lobes

cytoplasm contain lysome enzymes and bacteriducal compounds

function: engulf microorganisms with phagocytosis

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What is the structure and function of monocyte?

dark bean shaped nuclues and clear cytoplasm

largest leucocyte twice diameter of rbc

Function: individual monocyte stays in circulatory system for 24 hours or more until it migrates into peripheral tissues to become a macrophage. which is an aggressive macrophage that engulf microorganisms and realeases chemical to stimulate other phagocytes

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What is the structure and function of Lymphocyte?

dark nucleus with thin layer of cytoplasm 

function: migrate from bloodstream to peripheral to bloodstreamm

two types T cells- cell distruction or control other lymphocytes

B cells- produce antibodies

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Outline roles of membrane within and at the surfac

Surface- seperates cell from environment

controls entry and exit of ions and nutrients

phospholipid bilayer to prevent and allow certain molecules to pass through layer

Channel protein- to move molecules through facilated diffusion into the cell e.g water 

Contains receptor which allow cell to recognise and respond to specific molecules in environment 

glycoproteins- involved in cell recognition and cell adhesion


compartamentalise/surrounds organelles

prevents disruption of process/reactions

reactions take place within and enzymes fuse with membrane

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Outline structure and function of platelets?

structure- flattened discs from above and spindle shaped on blood smear

fragmented cytoplasm and no nuclues

contain enzymes and pro-enezymes

held in spleen and other vascular organs

Function: 1) realeases enzymes which initate and control clotting process

               2) clumps together at injury site to reduce bleeding

              3)contraction of filaments- contain actin and myosin which contract shrinking the clot

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Difference between leukocyte and palisade mesophyl

palisade mesophyll has cell wall (structural support and protection and filters)

large permenant vacuole ( contains cell sap and keeps cell rigid) 

chloroplasts ( absorb light to produce carbohydrates through photosynthesis)

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Whats the function of rough and smooth ER?

Rough- modifies and synthesises new proteins

smooth- lipid and carbohydrate synthesis

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Outline function of nucleus and Nucleolus?

nucleus- contains genetic information ( dna) and controls cell activity

nucleolus- ribosomes are made here

ribosomes- invoved in protein synthesis

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Whats the function of mitochondria and lyosomes?

mitochondria- involved in aerobic respiration and production of ATP

lyosomes-contains enzymes for intercellular digestion

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Whats the function of glogi apparatus?

synthesis of glycoproteins,polysaccharides and hormones

production of lysosomes

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Outline production and secretion of proteins (orga

-gene on chromatin codes for protein which is copied to mrna and leaves through nuclear pore

- associates with ribosome on rough r.e.r where protein is  packaged and modified into vesicles and transported to glogi apparatus

- glogi apparatus modifies and packages again into more vesicles

- which make their way to cell surface membrane to fuse with and realease antibodies into cell

- requires atp from mitochondria

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What type of plant cell doesnt contain chloroplast

- root cell

- xylem


sieve tube

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