Cardiovascular Physiology Flashcards
1
Q
P wave (ECG)
A
Result of depolarisation from SA node to AV node
2
Q
QRS complex (ECG)
A
Result of the ventricular depolarisation and precedes ventricular contraction
3
Q
T wave (ECG)
A
Caused by ventricular repolarisation
4
Q
Stroke Volume influenced by:
A
- Volume of blood in ventricles
- Changes in sympathetic nervous system
- Changes in arterial pressure
5
Q
Regulation of HR
A
- If blood volume drops, then SV declines and CO is maintained by increasing HR
* Chronotropic factors - Controlled by nervous system affecting ion channels
* Sympathetic increases HR
* Parasympathetic decreases HR
6
Q
- Respond to changes in arterial pressure
- Highly sensitive to stretch/distortion
- Degree of stretching is directly proportional to blood pressure
- An increase in pressure leads to increase in AP firing
- Short term changes in blood pressure
A
Arterial baroreceptors
7
Q
- Network of connected neurons
- Medulla oblongata
- Input from various baroreceptors
- Input determines AP frequency CV centre
- Increased firing of baroreceptors, decreased sympathetic outflow, increased parasympathetic outflow
- Decreased arterial pressure, increased plasma concentrations of hormones, which increases arterial pressure by constricting arterioles
A
Medullary CV Centre
8
Q
- Norepinephrine acts on beta-adrenergic receptors to increase ventricular contractility
- Increased contractility results in greater SV due to a more complete ejection of the end-diastolic volume
A
SV - Contractility
9
Q
- The ventricle contracts more forcefully during systole when it has been filled to a greater degree during diastole
- Due to length-tension relationship
- End-diastolic volume is determined by how stretched the ventricular sarcomeres are before contraction
- The greater the end-diastolic volume, the more the muscles are stretched and thus greater the contraction
A
SV - Frank Marlin Mechanism
10
Q
Muscular sack enclosing heart
A
Pericardium
11
Q
Fixes inner layer of pericardium to heart
A
Epicardium
12
Q
Muscular wall of the heart formed from cardiac muscle cells
A
Myocardium
13
Q
Muscular wall separating the ventricles
A
Atrioventricular Septum
14
Q
Limit movement to prevent backward flow of blood
A
Papillary muscles
15
Q
- Permit flow from atrium to ventricle
- Left valve - bicuspid
- Right valve - tricuspid
A
Atrioventricular Valves
