Clinical Sciences Flashcards
What is the function of leptin?
Lowers appetite
Which hormone stimulates hunger, and from where is it produced?
Ghrelin
P/D1 cells of fundus of stomach and epsilon cells of pancreas
What does leptin stimulate?
The release of melanocyte stimulating hormone and corticotrophin releasing hormone
Where is central control of respiration?
Medullary respiratory centre, apneustic centre in lower pons, and pneumotaxic centre in upper pons
What do chemoreceptors respond to?
Raised CO2 and H+1
Where are peripheral chemoreceptors located?
Carotid and aortic bodies
What is the function of the Hering Bruer-reflex?
Avoids lung over-distension through an inhibitory feedback loop; terminates inspiration and initiates expiration when stretch receptors are activated.
What is the change in lung volume per unit change in airway pressure?
Lung compliance
What are the causes of increased and decreased lung compliance?
Increased - age, emphysema
Decreased - pulm oedema/fibrosis, kyphosis
What is the main functioning component of pulmonary surfactant?
Dipalmitoyl phosphatidylcholine (DPPC)
What is the function of pulmonary surfactant?
- Reduces alveolar surface tension, prevents alveoli from collapsing
- Decreases work of breathing by reducing the muscular force needed to expand the lungs
- Lowers elastic recoil at low lung volumes
Name 4 physiological responses to hypoxia
Vasoconstriction of pulmonary arteries
Increased respiratory rate
Increased tidal volume
Tachycardia
What test allows assessment of upper airway obstruction?
Flow volume loop
What is transfer factor?
The rate at which a gas will diffuse from alveoli into blood
What is the difference between TLCO and KCO?
TLCO - total gas transfer
KCO - gas transfer corrected for lung volume - transfer co-efficient
Name 4 causes of raised TLCO
Asthma Pulm haemorrhage L-->R cardiac shunts Polycythaemia Exercise
Name 4 causes of reduced TLCO
Pulm fibrosis/oedema
PE/pneumonia
Emphysema
Anaemia
Name 3 conditions that increase KCO with a normal or reduced TLCO
Pneumonectomy
Scoliosis
Neuromuscular weakness
What is tidal volume?
Volume inspired or expired with each breath at rest
What is average vital capacity in males and females?
Males - 4.5L
Females - 3.5L
What causes a left shift in oxygen dissociation curve?
Low H+
Low pCO2
Low 2,3-DPG
Low temp
Macrophages produce which interleukins?
IL-1, IL-6, IL-8, TNF-alpha
Which interleukin activates macrophages?
IFN-gamma
Which interleukin causes neutrophil chemotaxis?
IL-8
What is the function of IL-5?
Stimulates production of eosinophils
What is the function of IL-2, IL-3, and IL-4?
IL-2: T cells
IL-3: myeloid progenitor cells
IL-4: B cells
Which cytokine is the anti-inflammatory cytokine, and what is it produced by?
IL-10
Th2 cells
What is the function of IL-1?
Increased expression of adhesion molecules on endothelium
Stimulates release of PAF, NO, prostacyclin
Vasodilation
What is the function of Th1 cells?
Cell mediated response
Delayed type IV hypersensitivity
Secrete IFN-gamma, IL-2, IL-3
What is the function of Th2 cells?
Humoral immunity e.g. stimulate production of IgE in asthma
Secrete IL4, IL-5, IL-6, IL-10, IL-13
What is the cause of macrophage activation syndrome?
IFN gamma activates macrophages
What is the diagnostic criteria of macrophage activation syndrome?
Ferritin >684 and 2 of: -Plts<181 AST>48 Triglycerides>156 Fibrinogen<360
What is the least abundant antibody in the blood?
IgE
What is the most common antibody in the blood?
IgG
Which is the first antibody to be secreted in response to infection?
IgM
What is the function of complement?
Chemotaxis
Cell lysis
Opsonisation
What does deficiency of C1q, C1rs, C2, and C4 predispose to?
Immune complex disease
What does C3 deficiency predispose to?
Recurrent bacterial infection
What is Leiner disease?
C5 deficiency
Diarrhoea, wasting, seborrheic dermatitis
What does C5 to C9 deficiency predispose to?
Neisseria meningitidis
What is the cause of hereditary angioedema?
C1 inhibitor deficiency leading to uncontrolled release of bradykinin
What is the function of the RER?
Translation and folding of new proteins
Manufacture of lysosomal enzymes
N-linked glycosylation
Where does steroid and lipid synthesis occur in the cell?
Smooth endoplasmic reticulum
Golgi adds mannose-6-phosphate to proteins for what reason?
Transport to lysosome
What is the function of the mitochrondria?
Aerobic respiration
Mitochondrial genome - circular DNA
Makes ATP
What is RNA splicing?
The process that removes introns (non coding gene sequences) from pre-mRNA and joins the exons
What occurs in the nucleolus?
Ribosome production
What is the function of the ribosome?
Translation of RNA into proteins
What is the function of the proteasome?
Degradation of protein molecules that have been tagged with ubiquitin
What is mean arterial pressure?
Average arterial pressure throughout cardiac cycle
Diastolic blood pressure x 0.66 and systolic blood pressure x 0.33
What are the causes of increased pulse pressure?
Less compliant aorta, increased stroke volume
Define stroke volume
End diastolic LV volume - end systolic LV volume
Which part of the antibody binds with cell surface receptors?
Fc region
Why is thiamine important to the catabolism of sugars and amino acids?
One of its phosphate derivatives, thiamine pyrophosphate (TPPP) is a co-enzyme in reactions such as pyruvate dehydrogenase complex
Causes of thiamine deficiency?
Malnutrition
Alcohol excess
What are the manifestations of thiamine deficiency?
Wernicke’s encephalopathy: nystagmus, ophthalmoplegia, ataxia
Korsakoff’s syndrome: amnesia, confabulation
Dry beriberi: peripheral neuropathy
Wet beriberi: dilated cardiomyopathy
Name 4 negative acute phase proteins
Albumin
Transferrin
Retinol binding protein
Cortisol binding protein