Foundations Year 2 Flashcards by Caitlin McMullen

What is the primary source of bilirubin in the body?

from the breakdown of haem from aged red blood cells

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What is the first step in bilirubin metabolism after haem is broken down?

Haem is converted to biliverdin, then to unconjugated bilirubin (indirect bilirubin)

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How is unconjugated bilirubin transported to the liver?

Unconjugated bilirubin binds to albumin and is transported to the liver

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How is conjugated bilirubin excreted from the body?

Conjugated bilirubin is secreted into the
1. bile
2. then enters the intestine

where it is either converted to urobilinogen or excreted asstercobilinin faeces

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What is the key difference between unconjugated and conjugated bilirubin?

Unconjugated bilirubin is lipid-soluble and bound to albumin, while conjugated bilirubinis water-soluble and can be excreted in bile/urine

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What are the three main categories of causes of jaundice?

Pre-hepatic
= haemolysis
Hepatic
= hepatitis, Crigler-Najjar
Post-hepatic
= biliary obstruction

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What is the primary cause of hepatic jaundice?

Impaired liver function, such as in hepatitis, cirrhosis, or genetic conditions like Crigler-Najjar and Gilbert’s syndrome

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What is the primary cause of pre-hepatic jaundice?

Haemolysis (destruction of RBCs) leading to increased unconjugated bilirubin

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What causes post-hepatic jaundice?

Biliary obstruction = such as from gallstones, pancreatic cancer
biliary atresia = leading to increased conjugated bilirubin

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At what age is neonatal jaundice considered pathological?

Neonatal jaundice is considered pathological if it appears before 24 hours of age

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What is the most common cause of pathological neonatal jaundice?

Haemolytic disease of the newborn
= ABO incompatibility
= Rh incompatibility

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How is neonatal jaundice investigated?

serum bilirubin
Coombs test
blood group(mother and baby)
FBC
infection screen (blood cultures)

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What is the first-line treatment for neonatal jaundice?

Phototherapy, which uses blue light to convert unconjugated bilirubin to a water-soluble form

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When is exchange transfusion indicated for neonatal jaundice?

serum bilirubin levels are extremely high or phototherapyis ineffective

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What is Dubin-Johnson syndrome?

A rare condition with impaired excretion of conjugated bilirubin, leading toconjugated hyperbilirubinaemia and a black liver on histology

It’s typically benign

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What is Gilbert’s syndrome?

A benign condition with mild deficiency of UDP-glucuronyl transferase

= leading to intermittent unconjugated hyperbilirubinaemia, often triggered by stress, fasting, or illness

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What is Rotor syndrome?

A condition similar to Dubin-Johnson, but without the pigmented liver

It also causes conjugated hyperbilirubinaemia but is typically benign

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What is the difference betweenCrigler-Najjar syndrome Type I and Type II?

Type I
= Complete absence of UDP-glucuronyl transferase →severe unconjugated hyperbilirubinaemia
= high risk of kernicterus
Type II
= Partial enzyme activity →milder hyperbilirubinaemia

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What is the mechanism of Rhesus (Rh) incompatibility?

Rh-mothers can become sensitised during the first pregnancy with an Rh+ foetus, producing IgG antibodies.

In subsequent pregnancies, IgG crosses the placenta and causes haemolysis of the foetal RBCs

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How do you prevent rhesus haemolytic disease?

Give Anti-D immunoglobulin to Rh-mothers after delivery or any sensitising event
= miscarriage, trauma etc

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What does a Coombs test detect?

The direct Coombs test detects antibodies on neonatal RBCs, while the indirect Coombs test detects maternal anti-Rh antibodies

Rh- mother + Rh+ baby leads to what happening?

Immune sensitisation

First pregnancy
= IgM (no placental crossing)
Subsequent pregnancies
- IgG crosses placenta → foetal haemolysis

What are the typical LFT findings in pre-hepatic jaundice?

(1) ↑ Unconjugated bilirubin

(2) Normal ALT, AST, ALP, and GGT

(3) Cause
= Excess haemolysis
(eg, haemolytic anaemia)

What are the typical LFT findings in hepatic jaundice?

(1) ↑ ALT and AST (often > ALP)
= hepatocellular pattern

(2) Mixed rise in conjugated and unconjugated bilirubin

(3) ALP and GGT may be mildly elevated or normal

(4) Cause: Hepatocellular damage
(eg, hepatitis, cirrhosis, Gilbert’s)

What are the typical LFT findings in post-hepatic (obstructive) jaundice?

(1) ↑ ALP and GGT (often > ALT/AST) = cholestatic pattern (2) ↑ Conjugated (direct) bilirubin (3) ALT/AST may be mildly elevated (4) Cause: Bile flow obstruction (eg, gallstones, pancreatic cancer)

Define homeostasis

The process by which the body maintains a stable internal environment despite external changes

: What is a negative feedback loop? Give an example

A mechanism where a change triggers a response that opposes the change Example = high blood glucose = insulin = lowers glucose = shuts off insulin release

What hormones regulate calcium homeostasis?

1. PTH = ↑ blood calcium 2. Calcitonin = ↓ blood calcium 3. Vitamin D = ↑ calcium absorption from the gut

How is temperature homeostasis maintained?

Via hypothalamic regulation 1. shivering and vasoconstriction when cold 2. sweating and vasodilation when hot

Describe the hormonal control of blood glucose

1. Insulin (from β-cells) = decrease in blood glucose by increasing uptake/storage 2. Glucagon (from α-cells) = Increase in blood glucose via glycogenolysis and gluconeogenesis

What is positive feedback? Name a physiological example

The response amplifies the initial stimulus Example: oxytocin during childbirth

What are the primary components of the body's feedback systems?

(1) Sensor (receptor) = Detects environmental changes such as body temperature and blood glucose (2) Integrator (control centre) = Typically the brain (hypothalamus) or endocrine glands, compare the current state with the desired set point (3) Effector = Executes the response to bring the body back to homeostasis Such as muscle contractions for shivering, sweat glands for cooling

What are the physiological processes that occur when the body is exposed to cold temperatures?

1. The body responds with vasoconstriction (to preserve heat) 2. shivering (to generate heat) 3. release of ADH (to conserve water)

Describe how the kidneys contribute to homeostasis in terms of blood pressure regulation

via the RAAS system

What makes you warmer?

The cold response 1. Shivering 2. Vasoconstriction (reduces heat loss) 3. Piloerection (goosebumps).

What makes you cold?

The hot response 1. Sweating 2. Vasodilation (increases heat loss) 3. Decreased metabolic rate

Diseases with a high anion gap >16

1. DKA 2. Addison's disease 3. Rhabdomyolysis 4. Erythema Multiforme 5. Toxic epidermal necrolysis (TEN)

A patient presents with hoarseness and undergoes a biopsy of an irregular area on the vocal cord. The biopsy shows viable fibrocollagenous tissue and an inflammatory infiltrate composed mainly of lymphocytes and plasma cells. What type of inflammatory process is this?

Chronic inflammation

What is seen in chronic inflammation?

lymphocytes, plasma cells, macrophages, fibroblast

What is seen in acute inflammation?

neutrophils, oedema, early fibrin, vascular changes

Granulomatous inflammation would show what?

aggregates of histocytes

Abscess formation would show what?

pus

What is an enzyme that transcribes genetic material?

RNA polymerase

Which statement is characteristic of a disease/condition due to a heritable mutation in mitochondrial DNA?

The condition can only be transmitted from an affected mother to her children

Karyotype analysis of bone marrow mitotic cells arrested in metaphase is performed in a patient with suspected malignancy. A single copy of Chromosome 7 is identified instead of the usual two copies. What term describes this chromosomal abnormality?

Monosomy = The loss of an entire chromosome, leaving one of the partners is monosomy

Uniparental disomy refers to what?

situation in which 2 copies of a chromosome come from the same parent, instead of 1 copy coming from the mother, and 1 copy coming from the father

Many anti-cancer drugs produce their effects by activating a family of proteins in a cascade-like fashion to trigger the common end-stages of apoptosis. Which family of proteins is being referred to?

Caspase

Scientists in the department of genetics at Ninewells Hospital are analysing transcripts within bone marrow cells from patients attending the haematology department. Which describes the material the analysis is being performed on?

RNA

A 25-year-old man presents to his GP. He is concerned because his sister has recently been diagnosed with breast cancer at the age of 30 years and has been found to have a BRCA2 mutation. He wants to be tested for the mutation because he has heard that he would be at increased risk of breast cancer if he also has the mutation. If he were to be BRCA2-positive, what other form of cancer would he be most likely to be at increased risk of?

Prostate

What is most commonly associated with the formation of granulomas in chronic inflammation?

Macrophages