Case 1 Flashcards
What binds the thorax
The superior thoracic aperture and the diaphragm inferiorly
What are the anterior and posterior boundaries of the thorax
Anteriorly the sternum and posteriorly thoracic vertebrae
What is in the superior mediastinum
Aortic arch and branches SVC oesophagus and trachea phrenic and vagus nerves cardiac plexus and sympathetic chain thymus and thoracic duct
What is the boundary of the superior and inferior mediastinum
thoracic plane at T4/5 and rib 2
What is in the middle mediastinum
Ascending aorta SVC and pulmonary trunk heart and peicardium trachea and bronchi nerves and tracheobronchial lymph nodes
What is in the posterior mediastinum
Descending thoracic aorta Oesophagus thoracic duct azygous and hemiazygous veins many arteries and the sympathitc trunk
At what point does the thoracic aorta become the abdominal aorta
when it passes through the abdominal hiatus at level T12
What main arteries go to the head and neck region and the arms
The common carotid and subclavian
What arteries branch off to supply the ribs
The posterior intercostal arteries
What arteries supply the bronchus
The bronchial arteries
Where does the celiac trunk branch off the abdominal aorta and what does it supply
At T12 to supply the stomach and liver
Where is the superior mesenteric artery found and what does it supply
L1 and it supplies the intestines
Where do the lumbar arteries branch off and what do they supply?
Each lumbar segment and they supply the posterior muscles
Where does the inferior mesenteric artery branch off and what does it supply
L3 to supply the intestines and rectum
Where does the aorta split into the two common iliac arteries?
L4
Where do the renal arteries branch off?
L1
What veins form the superior vena cava
The left and right internal jugular veins and the subclavian veins join together to form the brachiocephalic veins that join to form the SVC
What forms the inferior vena cava and at what levels
The two common iliac veins- right at L5 and left at L3
Also the lumbar, renal and hepatic veins
What is the extracellular matrix made up of
collagen and elastic fibres
What cells maintains the extracellular matrix
Fibroblasts
What are examples of specialised connective tissue
Cartilage, bone, blood and blood vessels
What is the order of blood vessel layers from superior to deep
Tunica externa (adventitia), Tunica media then tunica intima
What is the tunica externa made of
many collagen fibres and some elastic fibres and it is the thickest layer
What is the tunica media made of
smooth muscle and supported by connective tissue
what is the tunica intima made of
epithelial cells
connective tissue layers
some collagen but no fibroblasts
Where can you find the internal elastic lamina
in the tunica intima and media
What is the vaso vasorum
small blood vessels between the tunica media and externa that supply the muscles in the vessel walls
What is the first stage of atheroma formation
damage of the endothelial cells in the lining of the vessel to initiate an inflammatory response
What is deposited in the vessel wall to begin atheroma formation and at what layer
LDL move into the tunica intima and deposit cholesterol
What are foam cells
the macrophage complex with the cholesterol in the vessel wall
What results out of the rupturing of the fibrous cap during atheroma formation
A clotting cascade prevents the contents spilling out which results in the formation of a thrombus
What clinical manifestations can atheroma (chronic swelling) lead to
Aneurysm is a localised swelling of the wall of an artery that may rupture
Thrombosis is a stationary blood clot in the vessels
Embolus is a blood clot that moves around the blood system until it gets lodged
stenosis is the abnormal narrowing of a body passage
ischaemia
What is the difference between acute and chronic inflammation
Acute inflammation leads to the removal of harmful material and healing of the wound whereas chronic inflammation doesn’t lead to recovery and a constant state of alert persists in the body
How do you calculate the mean arterial pressure using cardiac output and total peripheral resistance
MAP= COxTPR
What is the cardiac output
the amount of blood the heart can pump in one minute
How do you calculate cardiac output using stroke volume and heart rate
Stroke volume x Heart rate
What is the simple mechanism of ACE inhibitors
Inhibition of the angiotensin-converting enzyme in the RAA system to prevent angiotensin I from converting to angiotensin II
How are ACE inhibitors administered and hat is their half life
Orally- 12 hours
What patients shouldn’t receive ACE inhibitors and why
Those ho are renally impaired as ACE inhibitors can lead to acute damage of the kidney as a result of effecting vasodilation- reducing blood flow to the organ
This may cause hyperkalaemia as the kidney is unable to remove potassium effectively
What are side effects of ACE inhibitors
Angioedema- swelling of the skin
Cough- most common
What is the role of angiotensin II in the body (5)
Increases sympathetic activity
Increased tubular Na+ and Cl- absorption and increased K+ excretion thus increased H2O retention
Increased aldosterone secretion
Increased arteriolar vasoconstriction to increase BP
Increased ADH secretion in the pituitary gland so increased permeability of the collecting duct
What is the common suffix of ACE inhibitors
-pril
What do angiotensin receptor blockers do
Act as a competitive inhibitor for angiotensin II in constricting arterioles so prevent this
Give an example of an ARB
Losartan
What do calcium channel blockers do? (3)
inhibit the influx of calcium ions into the myocardial muscle
Inhibit formation and propagation of depolarisation in the myocardial system
Vasodilation by reducing vascular tone in the coronary and systemic circulation
What is an example of a calcium channel blocker
amlodipine
What is the mechanism of diuretics
Blocking the reabsorption of Na+ and Cl- to reduce water reabsorption
What are possible side effects of diuretics and contrindications
Electrolyte imbalance and Addison’s disease
Old people are particularly vulnerable
What is an example of a diruetic
Indapamide
How is resistance related to the radius or diameter of a blood vessel
Resistance is inversely related to the radius or diameter of a vessel to the power of 4
How is resistance related to blood viscosity or vessel length
Resistance is directly proportional to blood viscosity or vessel length
hat is the difference in consequent resistance when increasing the resistance in one component of the vascular system in comparison to the organ system
If you increase the resistance in one part of the vascular system the total resistance increases across it
however in the organ system the organs have a parallel relationship so a change in resistance in one doesn’t effect the total resistance across every organ
How is blood flow related to pressure and resistance
it is directly proportional to pressure and inversely proportional to resistance
How does blood velocity relate to cross sectional area (number of branches and width of vessels)
It is an inversely proportional relationship
What is the autonomic nervous system
the part of the nervous system responsible for control of the bodily functions not consciously directed, such as breathing, the heartbeat, and digestive processes.
How does the autonomic nervous system affect arterioles in response to a stretch in the arteriole walls
It initiates a sympathetic response that constricts smooth muscle in the arteriole wall to vasoconstrict
What four forces contribute Starling’s forces and when do they come into play
Hydrostatic and oncotic in both the interstitium and capillary
Hydrostatic capillary and oncotic interstitium at arteriole end
Oncotic capillary and hydrostatic interstitium venous end
How do you calculate MAP using systolic pressure and diastolic pressure
MAP= DBP+ 1/3(SBP-DBP)
or
MAP= (SBP+2DBP)/3
Where are high pressure baroreceptors found
In the wall of the aortic arch and carotid sinus nerve
What do baroreceptors sense in order to recognise a change in BP
A change in the stretching of the wall of a blood vessel
When do baroreceptors fire action potentials, hen the wall is stretching more or less?
More- the greater the stretch the more action potentials that are fired
Where are low pressure baroreceptors found and what do they detect
In the atria and venoatrial junctions of the heart
These detect blood volume changes as oppose to pressure
hat does increased baroreceptor firing mean f or sympathetic and vagal responses
Decreased sympathetic response and increased vagal response
What happens to blood pressure when you stand up and what accommodates this
The blood pools to your lower limbs through gravity- decreasing the pressure in the aorta and thus baroreceptors fire off fewer action potentials to accommodate this change
This increases HR rapidly and sympathetic response
Where are lymph nodules found
Around the outer cortex of a lymph node
Where are mature T-cells located in a lymph node
In the paracortex
What is the hilum of a lymph node
Where a blood vessel enters and leaves a lymph node and where an efferent lymphatic vessel exits
What does lymph travel through to enter and exit a lymph node
The afferent lymph vessel enters the lymph node and the efferent exits it
Where does most lymph drain through
The thoracic duct
Where does lymph from the thoracic duct drain back into
the left venous angle in the venous system
What is the role of the lymph (3)
Drains interstitial fluid from the extracellular space
Transports dietary lipids in the lacteals
Works with the immune response as a defence mechanism
What do lymphatic capillaries drain
Interstitial fluid
Where are the lacteals found
The small intestine
How does the lymph act in an immune response (2)
It acts as a phagocytic filter to prevent unwanted particles from entering circulation
It also provides a site for lymphocytes to come into contact with antigens to increase the immune response- this occurs in the cortex of a lymph node
How is the lymphatics system flow maintained (2)
hydrostatic pressure pressure between the interstitial fluid and lymph as hydrostatic pressure goes through an expansion and compression phase
Peristalsis of the gut also assists movement
What happens to the valves between the interstitium and lymph during expansion phase and what does this result in
primary microvalves open whilst secondary close
this allows interstitial fluid to flow into the lymphatic system through a hydrostatic pressure gradient
What is the role of the thymus
T-cell development and maturation
What is the role of the spleen
filters blood cells and is the site of an immune response, destroying erythrocytes
What cells does the bone marrow produce
B-cells, T-cells and macrophges and red blood cells
What is anchoring
Relying too heavily on the first bit of information we are given
What is confirmation bias
when we think of a hypothesis and only search for the evidence that supports our theory
What is epidemiology
The study of how often diseases occur in certain populations and why
What are health inequalities
Differences in health between different groups within a society such as social class/socioeconomic status, social deprivation and/or ethnicity
What does mortality of a disease refer to
The number of deaths from a disease divided by the population
What does incidence of a disease mean
The incidence of a disease is the rate at which new cases occur in a population during a specified period
What is prevelance
The proportion of people in a population who are found to be affected by a medical condition at a specific time
What are the social determinants of health
The conditions in which people are born, grow, live, work and age
What is the inverse care law
The availability of good medical care varies inversely with the need for the population served
What is Vd- the volume of distribution
The volume of fluid that a drug would need to be dissolved in order for the known amount given to produce a measured plasma concentration fo the drug
What is C0
The initial concentration of the drug in the plasma at t=0 and corresponds to the highest plasma concentration
what is T 1/2
the half life of a drug- the length of time it takes for the plasma concentration of a drug to half
What is Cl in pharmacokinetics
Clearance of plasma- the volume of plasma cleared of drug per unit time and is an index of how well the drug is cleared from the circulation irreversibly
How do we work out the clearance of a drug using the elimination rate constant and Vd
Cl= Kel x Vd
How do we work out the elimination rate constant using the half life of a drug
t1/2= 0.693/kel
What is D with regards to a drug
D is the initial dose of a drug
What is the dosing rate of a drug
The rate at which a drug must be administered in order to achieve and maintain the desired plasma concentration of the drug
How do you work out Vd using C0 and D
Vd= D/C0
What does first order mean with regards to the removal of a drug as you add more of the drug
As you add more of the drug then more metabolising enzymes are recruited and the rate of removal is greater
What does zero order mean with regards to the rate of removal of a drug as you add more of the drug
This is when the metabolising enzymes are all saturated so the rate at which the drug plasma concentration reduces will be constant as they can’t recruit more enzymes to speed this up
What is a steady state of a drug
This is when, upon administration of a drug, the amount of drug administered exactly replaces the amount going out at an equilibrium point
What does a loading dose do
It attempts to reach the therapeutic range of a drug immediately by putting a large initial dose of the drug in however this can be risky as overshooting is a possibility
How do you calculate a loading dose using Vd and Css (steady state plasma concentration)
Loading dose= Vd x desired Css
What is a maintenance dose and how can it be calculated using Cl and Css
A maintenance dose is the dose required to keep a drug within its therapeutic range and can be calculated by Cl x Css
