Clinical Biomedicine

What does the red cell membrane consist of?

Lipid Bilayer with a negatively charged outer surface

Why is the outer surface negatively charged

to stop aggregation

What kind of metabolic activity do red blood cells complete?

anaerobic glycolysis

What is erythropoiesis?

production of red blood cells

Where does erythropoiesis occur?

in an adult, bone marrow of the sternum, pelvis and long bones

What is the function of Erythropoetin

To increase cell division and RBC numbers

What effect does renal hypoxia have on Erythropoetin production?

Increases it

What happens to RBC nuclei before release from the bone marrow?

They are extruded and phagocytosed

Where is erythropoetin produced?

Kidneys

What is the lifespan of a RBC?

~120 days

When are RBC's destroyed?

when senescent or defective they are destroyed by macrophages COME BACK TO THIS BIT WITH A VIDEO.

What is the function of haemoglobin

To transport oxygen around the body from the lungs
Transportation of CO2
To act as a buffer

What does a haem group consist of

Fe2+ atom in a porphyrin ring

Features of Oxyhaemoglobin

Bright red colour

Features of Deoxyhaemoglobin

Dark red colour

How does haemoglobin transport CO2

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How does haemoglobin act as a buffer?

the H+ ions left from dissociation of carbonic acid bind to globin chains which maintains stable plasma pH

Why is a stable plasma pH necessary?

to protect against respiratory acidosis

What is the structure of haemoglobin?

A tetrameric globular protein with four globin chains each surrounding a haem group

Name 3 advantages of artificial red blood cells

Universal administration
No disease transmission
Avoids religious issues

Name disadvantages of artifical red blood cells

Hb cannot be easily transfused
Not currently licensed for clinical use

Name 3 symptoms of anaemia

Pallor
Shortness of breath
Lethargy

At what level of HB is it classed as anaemia?

below 90-100 g/l

Microcytic

Small red blood cell

macrocytic

larger red blood cell

hypochromic

pale red blood cell

hyperchromic

very red red blood cell

What is an example of a normocytic normochromic anaemia

acute bleed

What is an example of microcytic hypochromic anaemia

Thalassemia or Iron deficiency

What is an example of macrocytic normochromic anaemia

B12 deficiency

How to treat iron deficiency anaemia

oral ferrous sulphate tablets or imferon injections

Causes of autoimmune haemolytic anaemia

drug induced (penicillin)
mycoplasma infection

What is the enzymopathy of congenital haemolytic anaemia

pyruvate kinase deficiency causing haemolysis

Pathology of sickle cell disease

HBs is insoluble in deoxy state which forms long crystals, distorting the rbc's

What are Heinz Bodies

oxidized, precipitated haemoglobin that damages the cell membrane

How are Heinz bodies removed

by macrophages

What is thalassemia

A group of inherited rbc disorders with reduced globin chain synthesis

Characteristics of alpha thalassemia

impaired ability to synthesis alpha globin chains
excess beta chains
mild microcytic hypochromic anaemia

Characteristics of beta thalassemia

impaired ability to synthesis beta globin chains
excess alpha chains binding to rbc membrane causing damage
hetero- mild microcytic hypochromic anaemia
homo - severe anaemia

What is Casgevy?

gene therapy to modify the gene that prevents the production of fetal haemoglobin so it can

What are polymorphonuclear leukocytes?

neutrophils
eosinophils
basophils

What are mononuclear leukocytes

Lymphocytes
Monocytes

Give an example of when neutrophils are elevated

Bacterial infection

Give an example of when lymphocytes are elevated

Viral infection

Give an example of when monocytes are elevated

Infection or inflammation

Give an example of when eosinophils are elevated

Allergy

Give an example of when basophils are elevated

Leukaemia

What colour do neutrophils stain with Romanowsky stains?

Neutral staining

What colour do eosinophils stain with romanowsky stains?

orange

What colour do basophils stain with romanowsky stains?

blue

What is the function of neutrophils

Phagocytosis

How do neutrophils move

amoeboid movement via pseudopodia

What is the structure of neutrophils

multi lobed nucleus

Blood tests of acute myeloid leukaemia

Over production of myeloid blast cells resulting in over crowding in the bone marrow

Blood tests of acute lymphoblastic leukaemia

Over production of lymphoid blast cells resulting in over crowding in the bone marrow

What is multiple myeloma

cancer of clonal plasma cells in the bone marrow

Age and the thymus

Shrinks with age causing a decline in immune function

What are the lymph nodes

a site of activation and division of activated t and b cells

What is the structure of a lymph node

Cortex
Paracortex
Medulla

Where are the locations of the tonsils?

Palatine
Lingual
Pharyngeal

Function of tonsils

Defend against pathogens entering nasally or orally

What gene mutations can cause unsuppressed growth

Oncogenes
Tumour Suppressor genes
DNA repair genes

Name some side effects of cancer therapy

Gonadal dysfunction due to radiotherapy or chemotherapy
Cisplatin causing vomiting, renal failure or hypocalcaemia

What are tumour markers

antigens on cancer cell molecules

When are tumour markers used?

For treatment follow up due to the low clinical sensitivity and specificity

Use of measuring albumin levels

Monitor liver function

Relation between albumin and colloid oncotic pressure

proteins cannot diffuse through capillary membranes and provide an osmotic pressure to maintain normal blood water volume

What happens with decreased albumin

increases water movement to the interstitial fluid causing oedema

Causes of low albumin levels

liver disease
poor protein intake
malabsorption conditions

Causes of high albumin levels

Dehydration
Steroids/Insulin

What is Caeruloplasmin

Specific carrier protein for copper

Disorder related to Caeruloplasmin

Wilson's Disease

How is amylase used to diagnose

Raised in pancreatitis and is used for acute abdominal pain and renal disease

How is lipase used to diagnose

Pancreatitis
is more sensitive than amylase

How is alanine aminotransferase used to diagnose

Raised in liver disease

How is creatine kinase used to diagnose

Raised in skeletal muscle damage and cardiac muscle damage

How is alkaline phosphatase used to diagnose

Raised in cholestatic liver disease

Function of antitrypsin

Protease inhibitor

5 stages of haemostasis

Vessel Spasm
Platelet plug formation
Coagulation
Clot Retraction
Clot dissolution

Function of thrombin

converts fibrinogen to fibrin

What is a bruise

bleeding under the skin

What happens to bruises after time

The leaked blood cells are phagocytosed and then degraded causing colour changes

What causes a red blue bruise

Haemoglobin

What causes a green bruise

Biliverdin

What causes a yellow bruise

Bilirubin

What causes a golden bruise

Hemosiderin

What causes abnormal bleeding

Vascular defects
Platelet number
Platelet function
Coagulation

What causes thrombocytopenia

Failure of marrow production
Shortened lifespan
Sequestration
Dilution