Lecture 14 week 8 Flashcards
What are factors influencing FRS?
- Age
- HDL-c
- Total-c
- SBP
- Smoking status
- Diabetes diagnosis
Is the risk of CVD greater in males or females?
Males
What is the cardiac cycle?
- Contraction of atria (atrial systole)
- Contraction of ventricles (ventricular systole)
- A rest (diastole) where neither chamber is contracting
What is the name for contracted state and which number is this in arterial BP?
Systole, and first number (120*/80)
What is the name for the relaxed state and which number is this in arterial BP?
diastole, and second number (120/80*)
What do cardiac muscle consist of?
Consists of individual cardiomyocytes connected by intercalated discs (gap junctions) working together as a single, functional organ
What are electrical signals propogated by?
- Nodes
- Nerves
- Intercalated discs (gap junction)
What does SA (sinoatrial) node do?
Where electrical impulses are generated (hearts natural pacemaker)
What does AV (atrioventricular) node do?
Connects the electrical systems of the atria and ventricles
What do nerves of the heart include?
Bundle of His, Bundle branches, Purkinje fibres
What can miscommunications in the heart lead to ?
Arrhythmia
What can abnormal SA node firing result in?
Can result in tachycardia (fast), bradycardia (slow)
What can blocks in heart lead to?
- E.g. at the AV node
- Vary in terms of degree of the blockage
- Can slow down or prevent signal propagation from atria to ventricles
- Ventricles can contract independently (Bundle of His, 40 bpm)
What can fibrillations lead to? what are the two types?
More serious, occurring when cells depolarize independently
* Atrial fibrillation (A-fib) – a quivering or irregular heartbeat (arrhythmia)
* Ventricular fibrillation (V-fib) – considered most serious cardiac rhythm disturbance
What can neural and endocrine signals control regarding the heart?
Controls strength and rate of heart contractions
What innervations can increase heart rate?
What innervations can decrease heart rate?
Sympathetic innervation (norepinephrine
Parasympathetic innervation (acetylcholine)
What specifically can increase strength of heart contraction?
Epinephrine
What can the heart do to adapt?
Enlargement of the heart
What are 3 examples of enlargement of the heart?
Over-working the heart
* Heart muscle responds with hypertrophy (similar to skeletal muscle after weight-lifting)
Endurance athletes
- Mostly an increase in LV chamber (need to increase cardiac output) Weightlifters
- Mostly increased LV wall & septum thickness (need to overcome increased afterload i.e. the amount of pressure needed to eject blood
during ventricular contraction)
Why can enlargement of the heart be bad?
Causes high blood pressure and narrowing of aortic valve
Heart must work harder to overcome this
Why can enlargement of the heart be good?
An appropriate adaptation for athletes
What is atherosclerosis?
Narrowing of arteries due to calcified fatty deposits (plaque), and thickening of the wall.
How is atherosclerosis triggered?
Triggered by damage to arterial wall (inflammation)
What can atherosclerosis lead to?
Can lead to heart attack or stroke
