1. One 2 One Medicine: Pre-clinical science revision course 2013
Key points
- Pacemaker cells have a depolarising pre-potential
due to high sodium permeability
- End-diastolic volume (pre-load) determines force of
contraction by controlling myocyte length
- Sympathetics increase SAN rate, reduce AVN delay
and increase ventricular contractility
- Heart failure causes right- & down-wards shift on
Frank-Starling curve
EXAMPLE

2. Anatomy
Myocytes
Cardiac cycle
Baroreflex
Coronary
circulation
Capillaries
Temperature
Exercise
Vasovagal
syncope
outlineModule
One-2-One Medicine: Pre-clinical science revision course 2014
EXAMPLE

3. haemodynamicsVessel
Total cross-sectional
area (cm2)
Velocity
(cm/s)
Blood pressure
(mmHg)
Elastic
arteries
Arterioles Capillaries Venules Veins
Muscular
arteries
One-2-One Medicine: Pre-clinical science revision course 2014
EXAMPLE

4. haemodynamicsVessel Flow = Arterial BP - Venous BP
Resistance
Perfusion pressure (ABP - VBP)
Flow
Low resistance
High resistance
One-2-One Medicine: Pre-clinical science revision course 2014
EXAMPLE

5. haemodynamicsVessel
↑ resistance↑ pressure
↓ pressure!
∴ ↓ flow
Flow
Vasoconstriction
Flow = Arterial BP - Venous BP
Resistance
One-2-One Medicine: Pre-clinical science revision course 2014
EXAMPLE

6. of blood pressureDeterminants
Systolic blood pressure - stroke volume
Diastolic blood pressure - heart rate & total peripheral
resistance
Blood
pressure
*SBP
*DBP
One-2-One Medicine: Pre-clinical science revision course 2014
EXAMPLE

7. Blood
pressure
*SBP
*DBP
Systolic blood pressure - stroke volume
Diastolic blood pressure - heart rate & total peripheral
resistance
of blood pressureDeterminants
One-2-One Medicine: Pre-clinical science revision course 2014
EXAMPLE

8. of blood pressureDeterminants
Systolic blood pressure - stroke volume
Diastolic blood pressure - heart rate & total peripheral
resistance
Blood
pressure
*SBP
*DBP
One-2-One Medicine: Pre-clinical science revision course 2014
EXAMPLE

9. Blood
pressure
*SBP
*DBP
Systolic blood pressure - stroke volume
Diastolic blood pressure - heart rate & total peripheral
resistance
of blood pressureDeterminants
One-2-One Medicine: Pre-clinical science revision course 2014
EXAMPLE

10. Blood
pressure
*SBP*SBP
*DBP
*SBP*SBP
Systolic blood pressure - stroke volume
Diastolic blood pressure - heart rate & total peripheral
resistance
of blood pressureDeterminants
One-2-One Medicine: Pre-clinical science revision course 2014
EXAMPLE

11. arteriolar toneFactors influencing
1. ENDOTHELIAL SUBSTANCES
2. MYOGENIC TONE
3. AUTONOMIC EFFECTS
4. METABOLIC HYPERAEMIA
5. HORMONES
6. PLATELETS: serotonin → vasoconstriction
One-2-One Medicine: Pre-clinical science revision course 2014
EXAMPLE

12. endothelial substancesArteriolar tone
↑ Shear stress
→ NO
→ Relaxation
↑ NO + ↑ PG Endothelial
cell
Vascular smooth
muscle cell
↑ shear stress
↓[Ca2+]
Relaxation
↑sGC
↑ cGMP
↑AC
↑ cAMP
One-2-One Medicine: Pre-clinical science revision course 2014
EXAMPLE