Physiology Cardio book Flashcards
Cardiovascular changes in pregnancy
Increase stroke rate 35%
Venous dilation 150%- due to increase plasma and
Red cell mass 20-30
Ventricular enlargement
Resting HR 15%
Frank starling law
Stroke volume is a function of end diastolic volume
Greater volume entering heart at diastole - greater stretch and SV
Due to Ca affinity to troponin C
BP in each area of heart and pulmonary circulation
Right atrium- 0-4
RIght ventricle- 25/0-4
Pulmonary artery-25/15
Left atrium- 5-10
Left ventricle- 120/0-10
What can you use to measure pulmonary artery pressure and estimate left atrial pressure
Stanz ganz catheter
Cause of third and fourth HS
3rd- rapid ventricular filling- dilatation
4th- ventricular hypertrophy/HF- due to forceful atrial contraction
Normal central venous pressure
8-12
Wnckebach phenomenon
PR interval becomes progressively more prolonged until QRS is missed
Cause of high CO due to reduced peripheral resistance
Beriberi, AV fistula, hyperthyroidism, anaemia
Factors aiding recovery from shock
Baroreceptors- sympathetic stimulation
Reverse stress relaxation- vasoconstriction
Angiotensin- kidneys
Most important electrolyte in myocardial contracility
Intracellular Ca- bind to trop C activating actin-myosin
Pressures in capillary beds and interstitial tissues
Arterial end- filtration highest
Oncotic pressure highest venous end
% coronaries receive of CO
5%
Coronary blood flow
70-80ml/min rest
300-400 per 100g of tissue
O2 consumption of heart
8ml/100g at rest
Fick principal
The Fick principle states that the uptake or release of oxygen by a tissue is the product of the amount of oxygen delivered to the tissue times the difference in oxygen content between the blood entering and leaving the tissue.
Distribution of water in human body
2/3 of weight is water (66%)
Of that 2/3 intracellular (40%)
1/3 extracellular (20%)
Of which
2/3 Interstitial (13%)-between cells
Intravascular (6%)- blood
Transcellular (1%)- CSF, synovial fluid
Factors affecting turbulence of blood flow
Velocity v
Diameter d
Density p
Viscosity n
vdp/n
So increased velocity, diameter, density increase turbulence
Decreased viscosity increases
Where main site of RBC formation is in adults
Flat bones
Types of shock and features
Cardiogenic- increased PVR due to low SV
Neurogenic- loss of autonomic- low PVR
Septic- low PVR, high CO
Classification of shock
<15- <750ml- normal, slightly anxious, urine >30ml/hr
15-30- 750- 1500- HR >100, BP normal, urine 20-30
30-40- 1500-2000ml- BP low, urine 5-15, HR 120-140
> 40- >2000ml- BP low, urine neg, HR >140
Effects of haemorrhage shock on physiology
Increase in HR
Reduced central venous pressure
Splanchnic vasoconstriction
Waves of JVP and what causes them
a- atrial contraction
x descent- ventricle contraction
c wave- bulge in tricuspid
v wave- rapid atrial filling
y descent- opening of tricuspid passively
Abnormalities seen on JVP waves
Cannon a - complete HB, as contracting against closed TV
Large a- RVH, pulmonary HTN
Absent a- AF
Large V- TR
Features of cardiac cells
Have intercalated discs which join 2 together- z lines
Branched structure
Uninucleated
Involuntary striated muscle
Septal vs anterolateral vs lateral st changes
Septal- V1-3
Anterolateral- V1-6
Lateral- V4-6, I, aVL
Which organs contain which adrenoreceptors
a1- smooth muscle contraction- blood vessels, uterus, ureters, liver- gluconeogenesis and glycogenolysis
a2- negative feedback
b1- cardiac contractility
b2- smooth muscle relaxation
Bronchioles, GI, vessels
Liver- glycogenolysis and gluconeogenesis
Clotting cascade
Intrinsic- XII- XI- IX- VIII (activates X by IX)
Extrinsic- VII, X, tissue factor
Common X- II (thrombin)- I fibrin
V required from thrombin activation
Several stages require Ca
What happens when you stand in the CVS
SV falls
Increase in SVR
Reduction in baroreceptor stimulation causing reduction in vagal stimulation and increasing sympathetic
What causes stimulation of RBC production
High altitude
Resp disease
Haemorrhage
Increased RBC segregation products
Structure and properties of myoglobin
Single chain protein
Contains haem
Instant binding rather than cooperative
Hyperbolic dissociation curve
Store O2 in muscles- rapid release when needed
Pulse pressure during shock, exercise and ACEi
Narrow in shock
Increase in exercise
ACEi effective treatment of reducing PP
Types of haemoglobin
HbA- adults
HbF- fetus- higher O2 dissociation
HbS- sickle
Uses of Central venous catheter
CVP monitoring
TPN delivery
Drug infusion
Haemodialysis
Location of SA node
Blood supply
Nerve supply
RA near the entrance of SVC
RC blood supply
T1-4 symptomatic, vagal para
Normal EF
Around 60%
Increases with exercise
Baroreceptor location and properties
Wall of the heart
Carotid and aorta
Increase stimulation when stretched with more pressure - inhibits symp
Afferent from carotid part of glossopharyngeal
Aortic- vagus
Where is renin produced
Juxtaglomerular apparatus om response to low BP, Na or symp
Anrep and Bowditch effect
Anrep -Myocardial contractility increases with increase after load
Bowditch- Increase in MC in response to increased HR
When do papillary muscles contract
Prior to ventricular contraction
To close mitral and TV
Cardiac index
CI=CO/BSA (body SA)
Types of lymphatic vessels and properties
Initial lymphatics- valveless, no smooth muscle, in smooth muscle and intestinal walled, fluid transported due to muscular contractions
Collecting - valves, smooth muscle, contract via peristalsis
What is oedema
Accumulation in extravascular space
Nephrotic- transudate
