Heart Activity Flashcards
Why is the heart referred to as a double pump?
Double circulation: heart-> lungs and heart->tissues
Where does de-oxygenated blood return to the right atrium via?
The superior vena cava (from upper body), inferior vena cava (from lower body), coronary sinus (from heart muscle)
How does de-oxygenated blood get to the lungs?
via pulmonary artery for oxygenation and removal of carbon dioxide (by gaseous exchange)
What are the 4 chambers?
2 atria (right & left) 2 Ventricles
Where is the coronary sinus and what does it do?
At the back of the atrium. Empties blood from heart veins (muscle) into the right atrium
What are the pulmonary and aortic valves known as?
Semilunar valves
Where is the pericardium and what is its function?
Layer filled with fluid outside the epicardium that lets the heart slip around.
Do arteries or veins have the most pressure?
Arteries
What happens when the Aortic valve snaps shut?
The pressure decreases allowing flow back into the heart and prevents back flow. The snap causes a dicrotic notch.
How does de-oxygenated blood flow into the right atrium from the upper body, lower body and heart muscle?
Via the superior vena cava, inferior vena cava and coronary sinus.
What happens when the blood reaches the lungs? how does it get there?
Right atrium-> Right Ventricle-> Lungs via pulmonary artery. Gaseous exchange= Oxygenation and removal of Carbon dioxide .
Where does the oxygenated blood flow from the lungs/how?
To the left atrium via 4 pulmonary veins.
Where does oxygenated blood travel after it reaches the left atrium?
Left atrium -> Left ventricle-> Body via aorta.
Where is the sinoatrial node and what does it do?
Rear wall of atrium. AKA pacemaker- regular electrical discharge begins firing pattern of whole heart- brings heart to about 120bpm.
Where is the beginning of firing pattern for the whole heart seen on an ECG?
The P wave shows beginning contraction pushing blood to ventricles.
What/Where is the atrioventricular node? Where can you see it working on an ECG?
in wall between rich atrium and ventricle. Electrical discharge passes via AV bundle incl purkinje fibres to ventricles. Begins QRS complex.
What is the process of the QRS waves?
Q wave (atrium systole)-> ventricular contraction begins->R wave (atrium distole)-> S wave (ventricular excitation)
What happens at the T wave?
depolarisation of ventricles -> beginning of ventricular diastole (U)
Where does the heart receive external innervation?
Parasympathetic and sympathetic NS.
What is the SNS transmitter? How does the SNS innervate the heart?
Acetylcholine. Vagal inhibition of SA node (reduces HR to approx 70bpm), Vagal withdrawal increase HR
What is the PNS transmitter? How does the PNS innervate the heart?
norepinephrine. increase in rate of SA node discharge and increase excitability of cardiac tissue both increase HR output.
What does the baroreceptor reflex control? where are the baroreceptors?
Control HR-BP links. receptors in carotid sinus in neck
What is the RSA?
Respiratory sinus arrhythmia. natural cycle of arrhythmia that occurs though influence of breathing on flow of sympathetic and vagal impulses to sinoatrial node. HR variability in synchrony with respiration.
