Haematology. pulses and blood pressure Flashcards
What is haematology?
The study of normal and pathologic aspects of blood and blood cells
What is an erythrocyte?
Also known as a red blood cell. These biconcave discs lack a nucleus but contain haemoglobin (Hb) which allows oxygen to be transported to respiring tissues
What is a leukocyte?
generic name for white blood cell. Mainly function as part of the bodies defence. Examples are granulocytes: neutrophils, basophils and eosinophils and agranulocytes: monocytes and lymphocytes
What are the formed elements?
The cellular and cell fragment components of blood: cells (erythrocytes and leukocytes), platelets (thrombocytes) which are suspended in the plasma
What is plasma?
The straw coloured liquid component of blood made up of water, electrolytes and proteins
What is an antibody and antigen?
A protein produced by the immune system. Also called immunoglobulins. Produced in response to a foreign substance (antigen). Antibodies recognise specific antigens and bind to them so they can be removed from the body
What is blood pressure?
Pressure of force that moves circulating blood around the body through our circulatory system, specifically measured in our arteries. Blood pressure readings consist of two number: the systolic pressure first and the diastolic pressure second. Readings are given in mmHg
What is the systolic phase?
The phase of cardiac cycle when the ventricles are contracting. This is the higher of the two numbers
What is the diastolic phase?
The phase of the cardiac cycle when the ventricles are relaxing. This is the lower of the two numbers
What are things to note about health and safety to do with this practical?
- PPE should be worn whenever we are handling human tissue or human body fluid (blood)
- Gloves should be worn at all times – blood should never be handled directly
- Individuals who appear healthy may be carriers of infectious hepatitis
- Risk of HIV transmission
- Treat all blood as infected
- Dispose all used or contaminated items the correct way in the correct place
What does blood do?
- Transports gases
- Carries nutrients, hormones, waste products and heat
- Involved in inflammation and contains antibodies which are responsible for the recognition and destruction of foreign micro-organisms and for triggering the immune response.
What does blood consist of?
Plasma and formed elements
What does plasma play roles in?
immunity, transport and osmotic effects
What are the formed elements of the blood involved in?
gas transport, immunity and the arrest of bleeding (haemostasis)
What type of blood sample could be collected for a blood test?
venous or capillary
What is the procedure for obtaining a sample of capillary blood using a single lancet?
- Wipe finger with alcohol wipe and allow to dry (otherwise blood will smudge and it will be hard to obtain the sample)
- Massage bottom of finger gently
- Press the lancet against your finger and then push on the button
- It will always retrieve safely after use
- Dispose of the lancet in the yellow bin
- Squeeze the bottom of the finger until blood comes out
give examples of uses of small finger prick samples
- Blood glucose levels
- Cholesterol testing
- Haemoglobin levels
- Covid antibody tests (trial June 2020)
- Used in laboratory tests e.g. making a blood smear to view blood cells
Is it easier to obtain good sample from a finger tip if the hand is warm of cold?
warm
What is venepuncture and when is it used?
- Where blood is taken directly from a vein in the forearm
- it is used when larger samples of blood are needed
How is venepuncture carried out?
- A tourniquet is placed around the upper arm to allow blood to pool in the vein making the vein easier to identify and enables the sample to be taken when a small needle is inserted directly into the vein
- A sample obtained by venepuncture is collected directly into a bottle containing an anti-coagulant such as EDTA (ethylene-diaminetetraacetic acid), a chelating agent that binds to calcium
What is a haemocytometer?
A specially ruled chamber
What is the manual method for measurement of blood cells?
pipetting a diluted blood sample into haemocytometer (a specially ruled chamber) and then observing it under a microscope
What are red blood cell counts and what are they used to do?
- they are commonly performed haematology tests that are usually part of the full or complete blood count
- the RBC count approximates the number of circulating red blood cells and is helpful in diagnosing and treating many diseases, especially anaemias
What other cells counts is a haemocytometer used for?
cell counts in semen and cerebrospinal fluid samples