Foundations of medicine Flashcards
What are the steps of aerobic respiration (4)
glycolsis
Link reaction
TCA cycle
Oxidative phosphorylation
Where does glycolysis occur
cytosol
What are the products of glycolysis (3)
4 ATP
2 NADH
2 pyruvate
What is the net ATP gain of glycolysis
2 ATP
What happens to the pyruvate produces in glycolysis
moves through H+/pyruvate symporter to the mitochondria via facilitated diffusion
Where do the link reaction and TCA cycle occur
mitochondrial matrix
What is the role of CoA (2)
acts as a shuttle
Takes acetate into the cycle, drops it off, then goes back for more acetate
What are the products of the link reaction + TCA cycle (4)
3CO2
3NADH
GTP
FADH
What are the enzymes that catalyse irreversible reactions in glycolysis (3)
hexokinase
Phosphofructokinase
Pyruvate kinase
How is pyruvate converted to acetyl-CoA
Pyruvate dehydrogenase complex catalyses oxidative decarboxylation of pyruvate, producing acetyl-CoA
Where is succinate dehydrogenase found
Integrated into the inner mitochondrial membrane
What happens during oxidative phosphorylation (4)
Electrons are passed through complexes in the respiratory chain
Energy released from this process is used to pump protons into the inter membrane space
The proton gradient created generates a potential energy difference and protons flow back into the matrix through ATP synthase
Electrons are transferred to oxygen, forming water
What shuttles allow the energy of electron transfer from NADH to be coupled to ATP generation (2)
Glycerol-3-phosphate
Malate-aspartate
What is the role of malate in cellular metabolism (3)
malate is generated from oxaloacetate by NADH
Malate transporters transfer malate to the mitochondrial matrix
Malate is converted to oxaloacetate
Describe the location of the different GLUT transporters (5)
1 brain
2 liver beta cells
3 Brain
4 muscle and adipose tissue
5 gut
What are the glycogen pathways (3)
Gluconeogenesis - making glucose from new sources
Glycogenolysis - breakdown of glycogen
Glycogen synthesis - making glycogen
Describe the process of glycogen synthesis (4)
glucose is converted to glucose-6-phosphate
An enzyme moves the phosphate to position 1
UTP is used to label glucose-1-phosphate into UDP glucose
Glycemic synthase adds it to the end of the chain and UDP dissociates
Where does gluconeogenesis occur
liver
What are the possible precursors for gluconeogenesis (3)
Lactate
Amino acids
Glycerol
how does gluconeogenesis work
Precursors join TCA cycle and make it continue in the absence of glucose
Where does lipogenesis occur
Liver
What happens in lipid metabolism (2)
fatty acids are oxidised to generate energy and are converted to CoA derivatives
Beta oxidation creates ketones which diffuse into the blood and peripheral tissues
For drugs with zero order kinetics, increase the concentration of the drug in the body has what effect on the rate at which the drug is excreted
no effect
What nerve is responsible for pericardial pain radiating to the left shoulder
phrenic nerve
What is a common side effect of Ace inhibitors
drug cough
Withdrawal of beta blockers can cause what
rebound tachycardia
If a patient has hypovolaemic shock and a HR of 125beats/min, stimulation of which receptor has compensated for blood loss
alpha 1 adrenoceptor (smooth muscle contraction)
What is the remnant of the ductus arteriosus
Ligamentum arteriosum
Where is the tricuspid valve best auscultated
Left 4th intercostal space at lower left sternal border
Mechanisms of action of clopidogrel
antiplatelet
ADP receptor antagonist
Where is the appendix found
retrocaecal
What is the mechanism of action of ticagrelor
Inhibit ADP binding to platelets
Mechanism of action of aminoglycosides
binds to 30S subunit, causing misreading of mRNA
What is the mechanism of action of clindamycin
binds to 50S subunit, inhibiting translocation
What is the mechanism of action of macrolides
Binds to 50S subunit, inhibiting translocation
What is the mechanism of action of tetracyclines
Binds to 30S subunit, blocking binding Of aminoacyl-tRNA
What type of dysfunction is myocarditis assocaited with
systolic dysfunction
Which type of heart failure leads to peripheral oedema, raised JVP, and hepatomegaly
right ventricular falire
Pulmonary oedema with paroxysmal nocturnal dyspnoea and bibasal fine crackles suggests what pathology
left ventricular failure
What type of outflow is the sympathetic nervous system
Thoracolumbar
What type of outflow is the parasympathetic nervous system
craniosacral
Where does afferents/sensory input go
Dorsal aspect of spinal cord
Where does efferent/motor output come out of
ventral aspect of spinal cord
How do action potential jump between nodes
Saltatory conduction
In unmyelinated nerves, how do action potentials travel
Contiguous conduction
What happens when action potentials reach the presynaptic neuron(‘s membrane??) (5)
calcium gates ion, calcium ions flow in
Vesicles move to and fuse with the presynaptic membrane
Neurotransmitters are released into synaptic cleft then bind with receptor on the postsynaptic neuron
Causing ion influx
Enzymes break down neurotransmitters and components are transported back to the presynaptic neuron
What types of receptor exist (4)
kinase linked
G protein coupled
Ligand gated
Nuclear
What are the types of healing (4)
resolution
Suppuration
Formation of granulation tissue (fibrosis)
Chronic inflammation
What does the type of healing that occurs depend on (3)
The organ’s capacity for repair
Severity of injury
Duration of injury
Describe suppuration
pus is produced containing neutrophils and bacteria/inflammatory debris
Favoured if infection is persistent with a limited blood simply
How does empyema form (pathology)
suppuration
Cavity is filled with pus and walled off
Describe necrosis (4)
involves an increase in cell size
Always pathological
Disrupters plasma membrane
Often causes nearby inflammation
What are the types of necrosis (5)
coagulative
Colliquative
Caseous
Gangrenous
Fat necrosis
Describe apoptosis (3)
reduction in cell size
Nucleus fragments/condenses
Plasma membrane remains intact
Describe autolysis
lysis of tissue by its own enzymes following the death of an organism
What are the groups of cells (based on healing abilities) (3)
labile (most able to regenerate)
Stable
Permanent (worst ability to regenerate)
Describe organisation (3)
occurs if an injury causes lots of necrosis/fibrin
Poor blood supply, debris are hard to remove
Damage goes beyond basement membrane
Describe process of granulation (5)
organised defect is infiltrated by capillaries
Infiltrated by myofibroblasts
Collagen and smooth muscle cells are deposited
Fibrosis and scarring occurs
Function is lost
Describe extrinsic pathway of apoptosis (4)
FAS ligand binds to FAS on extracellular membrane surface
Produces FAS-associated death domain
Signalling cascade activates caspases within cytoplasm
Controlled death inside cell
Describe intrinsic apoptosis pathway (3)
anti-apoptosis molecules are removed and replaced by BAX and bak2
Produces holes in mitochondrial wall
Mitochondrial proteins leaks into cell cytoplasm and activate caspases
What is the name of the molecule which is important in inducing the caspases response
Cytochrome C
Which type of necrosis is associated with TB
Caseous
What are the hallmarks of cancer (7)
promotion of cell growth
Inhibition of tumour suppressors
Unlimited replicative potential
Avoids apoptosis
Angiogenesis
DNA repair
Evasion of immune system
Which stage of the cell cycle is p53 involved in
G2
What is pharmacokinetics
what the body does to the drug
What is pharmacodynamics
what the drug does to the body
What does potency refer to
quantity of drug required to produce desired effect
What does affinity refer to
Strength of association between ligand and receptor
What does efficacy refer to
ability of an agonist to evoke a cellular response
What is the meaning of apparent volume of distribution
The volume of solution required to evenly distribute the drug
Which type of drug is the volume of distribution higher for + why
Higher for lipophilic drugs because they are more able to cross membranes
Which drugs have a low drugs plasma concentration but a high apparent volume of distribution
drugs with low plasma protein binding
What can be caused by Epstein Barr Virus
proliferation of B cells
Which drugs have a high drug plasma concentration but a low volume of distribution
drugs with high plasma protein binding
Where are drugs metabolised
On smooth endoplasmic reticulum of live hepatocytes
What occurs during stage one metabolism (3)
oxidation/hydrolysis/reduction
Involves cytochrome p450 enzymes
Toxic metabolites can be formed
What happens during phase 2 metabolism
conjugation (and glucuronidation)
In which metabolism phase can ester and amide bonds be hydrolysed
phase one metabolism
How are most drugs excreted (3)
combined with polar molecules forming a water soluble metabolite
Renal filtration
What are features of pharmacodynamics (3)
clearance
Drug elimination and half life
Bioavailability
What is meant by rate of drug clearance
the volume of plasma cleared of a drug per unit of time
What is meant by first order kinetics
the rate of drug elimination increases as the drug plasma concentration increases
What is meant by zero order kinetics (2)
The rate of drug elimination is not affected by the drug plasma concentration
Occurs when elimination mechanisms become oversaturated
Which type of kinetics do must drugs follow
first order (rate of elimination is affected by plasma concentration)
How many half lives are typically required for a drug to reach a steady state concentration
Five
What does steady state mean
the rate of drug administration equals the rate of elimination
Bioavailability of drugs increases/decreases when administrated orally
Decreases
What does cmax represent
when drug plasma concentration is at a maximum level
What does tmax represent
the time taken for cmax to occur
The effect of a competitive antagonist on a concentration responses curve (2)
shift to right
No change in maximum response
The effect of a non-competitive antagonist on a concentration responses curve (2)
does not cause a sideways shift
Causes reduction is maximum response (a depression in the curve)
What does a lower Ka indicate
The ligand has a high affinity for the receptor
What does Ka represent
the concentration of ligand required to occupy 50% of receptor sites
What is K+1
the number of receptors bound to the ligand (association rate constant)
What is K-1
the number of free receptors (dissociation rate constant)
What does the Hill-Langmuir equation do
Models the relationship between ligand concentration and receptor occupancy
S shape on graph
What is Vmax
The reaction rate reached at infinite substrate concentration
What is Km
The concentration of substrate required to reach 50% Vmax
How do the Michaelis-Menten curves differ in simple vs allosteric enzymes
Simple - standard curve
Allosteric - sigmoid curve
What is the effect of a competitive inhibitor on Vmax and Km
Vmax stays the same
Km is higher
Higher concentration is required to reach half the Vmax, but the maximum rate of reaction is the same
What is the effective of a non-competitive inhibitor on Vmax and Km
Vmax decreases
Km stays the same
What is stroke volume
volume of blood pumped (by each ventricle) per heart beat
What is cardiac output
the volume of blood pumped by each ventricle per minute
Where are baroreceptors located (2)
Carotid sinus
Aortic arch
If there is an increase in MAP, what is the effect on baroreceptors
baroreceptor firing increases
There is reduced sympathetic tone and increased parasympathetic activation
Decreased heart rate and systemic vascular resistance
What does sympathetic stimulation of alpha1 receptors cause
Vasoconstriction
What does sympathetic stimulation of beta2 receptors cause
Vasodilation
Which part of the nervous system is responsible for vasomotor tone
Sympathetic
Where is the vasomotor centre found
medulla oblongata
What are the components of RAAS (3)
renin
Angiotensin
Aldosterone
Role of renin (2)
released by kidneys in response to low blood pressure
Activates angiotensin I
Which gas law explains respiratory distress in premature newborns
La Place’s law
During CPR, when should the rescuer palpate the patient’s pulse
Only if the patient responds with purposeful movement
Which neurotransmitter acts on muscarinic receptors + what is the effect in the airways
Acetylcholine
Causes constriction of the airways
What is the reason for the difference between foetal and adult haemoglobin
Foetal haemoglobin has gamma subunits instead of beta subunits
This means it has a higher affinity for oxygen than adult haemoglobin
In foetal circulation, which shunt connects the pulmonary trunk to the aorta
ductus arteriosus
What is meant by neo-adjuvant treatment
treatment given before surgery to shrink the tumour for surgical removal
Which type of necrosis occurs in brain cells
Liquefaction
Why us genetic code described as unambiguous
each codon specifies one amino acid or stop codon only
What term describing an enzyme with a co-factor
holy enzyme
In gastric parietal cells, what acts on M3 receptors
acetylcholine
What is the rate limiting enzyme fro glycogenolysis
glycogen phosphorylase
What is the rate limiting enzyme in gluconeogenesis
fructose 1,6-biphosphonate
What is the rate limiting enzyme in lipogenesis
Acetylcholine-CoA carboxylase
What is the dominant immunoglobulin in the secondary immune response
IgG
Collections of calcium shown on histology suggest which condition
mesothelioma
What type of lesion is papilloma
a benign neoplasm of squamous epithelium
If afterload increases, what is the effect on end diastolic volume
End diastolic volume will initially increase
What is the shape of a macrophage’s nucleus
kidney shaped
Which cell is responsible for the destruction of large parasites which cannot be phagocytosed
Mast cells
Where are MHC class II molecules found
macrophages’ cell membranes
What type of intercellular junctions are present in the sinoatrial node of the heart
gap junctions
What method is most appropriate to detect Down’s syndrome or similar genetic disorders
array comparative genomic hybridisation
Which type of bacteria releases exotoxins
gram positive
In which step of acute inflammation do white blood cells bind tightly and flatten against the vessel wall
Pavementign
Which neurotransmitter is released within the synapses between post-ganglionic sympathetic neurons are their effector cells
Noradrenaline
What type of joint is the sternoclavicular joint
hinge type synovial joint
What type of joint is the elbow joint
saddle type synovial joint
What type of joint is the interosseous membrane of the forearm
fibrous joint
What type of joint is the pubic symphysis
secondary cartilaginous joint
what type of joint are intervertebral discs
primary cartilaginous joint
Which nerve supplies mechanoreceptors to the upper respiratory tract
vagus nerve (CN X)
