Lecture 10 Flashcards
What is pre-load?
The volume of blood entering the heart
What is after-load?
The resistance in the vessels to blood exiting the ventricles
What 2 laws determine changes that occur in short term challenges such as exercise?
Starling’s Law and the Bainbridge effect
What is isoprenaline?
A beta agonist. It causes E-C coupling to occur in a shorter action potential period. Leads to phosphorylation of T type and L type Ca2+ channels. this increases the calcium amplitude.
What does endurance training do to the pressure-volume loop?
Increases it.
What law applies to long term endurance training?
Laplace’s law.
What is Laplace’s law?
Chamber distension results in larger radius over time. sarcomeres are added in series. this is eccentric cardiac hypertrophy.
What type of exercise shows eccentric cardiac hypertrophy?
Endurance training
What type of remodelling occurs in pregnancy?
Eccentric remodelling
What increases with strength training?
After-load
Describe what happens with strength training
After load increases so the heart needs to pump with greater force to oppose the resistance. sarcomeres are added in parallel . increases thickness of muscle.
What type of hypertrophy occurs in strength training?
Concentric cardiac hypertrophy.
Why does myocardial infarction lead to increased sympathetic drive?
Baroreceptors sense the decrease in BP and try to increase it via the sympathetic pathway. Overstimulation by catecholamines occurs and increased leakiness through RyR.
What are some treatments for MI?
Diuretics reduce plasma volume and beta blockers block sympathetic nervous system.
