Week 2 Flashcards
What are the functions of blood films?
Detecting blood cell abnormalities or if patients have disease detectable in blood cells e.g. malaria
What information do blood films give and when are they requested?
Information on RBCS, WBS and platelets
When a patient has returned from a country where a disease is endemic
Usually performed with full blood count
What is a white cell differential and what is it used for?
Shows the proportions of WBCs in blood
Helps determine type of infection (bacterial, viral, parasitic)
How would you do a blood film?
- Take two microscope slides and clean them with ethanol on tissue
- Place one drop of blood on one end of one of the slides - creates monolayer to examine microscopically
- Hold the other slide at a 45 degree angle and slide it on the other slide until it reaches the blood
- Draw back the slide along the other slide
- Slide is then dried
What effect is seen on the slide when doing a blood film?
Feathered effect
Which type of WBC is this?
Eosinophil - bilobed nucleus
Which type of WBC is this?
Lymphocyte: large nucleus, not grainy
Which type of WBC is this?
Neutrophil - multi lobed nucleus
Which type of WBC is this?
Basophil - grainy, single nucleus
Which type of WBC is this?
Monocyte - kidney bean nucleus
What is the difference between gram positive and gram negative cell walls?
Gram positive have a thicker peptidoglycan wall
What is the order of stains in gram staining and what colour are they a each stage?
Crystal violet: put on both samples then washed, both purple
Grams iodine: traps dye in cell, incubated then washed, both purple
Ethanol: decolours gram negative bacteria, rinsed with water, neg = colourless, positive purple
Safranin: pink counterstain, gram pos purple, neg pink
What should always be performed when doing gram staining and why?
Controls: to ensure staining process has been carried out correctly
Why is gram staining done?
To identify which type/species of bacteria is present
Which type of parasitic egg is this?
Trichuriasis
Which type of parasitic egg is this?
Schistosomasis
What type of parasitic egg is this?
Ascaris
Why is oil immersion used?
Used with light microscope to see bacteria to give x1000 magnification , prevents
How can the immune system be improved to reduce disease caused by an infection?
By getting the infection/vaccinayion
Which virus has been made extinct through vaccination?
Smallpox
Give examples of things there are vaccinations for
Flu, cholera, polio, chickenpox, hep B
Examples of some physical barriers to infection?
Epithelial cells joined by tight junctions
Movement of mucus by cilia
Normal flora
Low ph in gut
Where are WBCs made?
the bone marrow - mostly pelvic area in adults, leg bones in children
Which cells are produced from a common myeloid progenitor?
Erythrocytes, megakaryocyte, mast cells, myeloblasts, basophils, neutrophils, eosinophils and monocytes
Which cells are produced from a common lymphoid progenitor?
NK cells, T and B lymphocytes
Where do T lymphocytes mature and why?
Thymus - checked to ensure they aren’t auto reactive and won’t cause autoimmune disease
List the WBCs in order of most prominent in blood to least.
Neutrophils (65%), lymphocytes (30%), monocytes (5%), eosinophils (2%), basophils (0.5%)
How long do neutrophils, eosinophils, basophils, monocytes and b and t lymphocytes live?
N - 7 hours
E - 8-12 days
B - few hours to few days
M - 3 days
BT - years
How do neutrophils carry out their function?
Chemotactic and phagocytic: chase and eat bacteria
Which cells leave the blood and take up long term residence in tissues and why?
Dendritic cells, macrophages, mast cells
They survey the tissue to ensure its healthy and there is no presence of infection/not damaged
If infection sensed then they protect the body
Name some secondary lymphoid organs.
Tonsils, adenoids, Peters patches of intestines, appendix, lymph nodes
Which cells are involved in the innate immune response?
Mast cells, NK cells, basophils, neutrophils, eosinophils, monocytes
Which cells are involved in the adaptive immune response?
T and B lymphocytes
What is inflammation?
A reaction of the body to damage to its cells and vascularised tissue
What are the aims of inflammation?
- Expel foreign body/infection
- Prevent metastasis
- Structural/functional repair
What are the 5 clinical features of inflammation?
Redness/rubour: vasodilation
Heat/calor: vasodilation and fever
Swelling/tumor: fluid in ECM
Pain/dolor: pain mediators e.g. serotonin
Loss of function/functio lasea: limb movement inhibited by pain/swelling
What are some cells/molecules that can induce inflammation?
Bradykynin: pain mediator produced in fibrinolysis
C5a: produced in complement and causes inflammation
Mast cells release histamine which can cause inflammation, also cytokines e.g. IL-6 and TNF which cause inflammation
Function of macrophages?
Phagocytose pathogens and kill with acidic/degregative lysosomes
How do macrophages/neutrophils recognise and kill?
They have phagocytic receptors that bind microbes and their components
The bound material is internalised in phagosomes and broken down in phagolysosomes
Function of Toll Like Receptors (TLRs)?
Recognise different PAMPs (pathogen associated molecular patterns)
They then activate macrophages/dendritic cels to cause an immune response
How can inflammation be bad?
They can sometimes outlive the threat they’re dealing with, causes more damage to the body than the infection would have caused e.g. allergies, autoimmune disease
Which diseases does inflammation underly?
Cancer, diabetes, alzheimers, arthritis
Which systems is the lymphatic system a part of?
Circulatory and immune
What is capillary filtration?
Plasma (liquid part of blood) is continuously removed from and returned to blood vessels
What is interstitial fluid?
Plasma not returned to blood vessels after capillary filtration, returned to lymphatic vessels instead
What makes up the lymphatic system?
Lymphatic vessels, lymph, primary and secondary lymphoid organs
What are the functions of the lymphatic vessels?
Drain lymph back into blood
Where does lymph drain?
Right upper body: right subclavian vein
Left upper body and lower body: left subclavian vein
Functions of lymph?
Transports immune cells
Removes waste products
Transports proteins and fats from digestive system
Where do B lymphocytes mature?
Bone marrow and then spleen/lymph node
Function of lymph nodes in lymphatic system?
Drains lymph and collects antigens
Activates immune response
What is microbiology?
The study of microorganisms and their relationships with humans