3.2 Transport In Animals (heart) Flashcards
How does blood enter the heart?
Via the Vena Cava
What is thicker the left atrium or the left ventricle?
The ventricle because the blood is travelling a further distance
What are the purpose of coronary arteries?
Supply cardiac muscle with oxygenated blood
What is the purpose of the Septum?
Prevents oxygenated and deoxygenated blood mixing
How does deoxygenated blood leave the heart?
Through the pulmonary artery
How does deoxygenated blood leave the heart?
Pulmonary Artery
How does oxygenated blood enter the heart?
The Pulmonary vein
What are the two main types of valves?
The Atrioventricular and the semi lunar
What is the definition of the cardiac cycle?
The sequence of events in one heart beat
What order does the cardiac cycle occur?
Filling phase (diastole)
Atrial contraction
Ventricular contraction
What are the features of the filling phase (diastole)?
Atria and ventricles are relaxed
Blood enters via pulmonary vein and Vena Cava
SL valves are closed
AV valves open
Blood flows passively from atria to ventricles
What happens if valves don’t work properly?
There’s a back flow of blood
What causes the AV valves to open?
Relaxed muscles create a higher pressure in atria than ventricles
What causes AV valves to close?
Ventricles contracting create a higher pressure in the ventricles than the atria
What sound do the AV valves make?
‘Lub’
What causes SL valves to open?
Ventricles contract increasing pressure in ventricles in comparison to aorta
What causes SL Valves to close?
Ventricles relax decreasing pressure in comparison
What sound do the semi-lunar valves make?
‘Dub’
What is the sino-atrial node and what is its role?
- Located in right atrium
Group of cells that can initiate their own impulse
How is cardiac muscle myogenic?
It can initiate its own contraction
What is the order of the electrical activity bringing about the cardiac cycle?
- Electrical activity from SAN spreads across both atria (brings about atrial systole)
- Atrioventricular septum blocks impulse but can pass via avn
3.Short delay - AVN conducts electricity down to the base of the ventricles (ensures atria finish contracting)
- Electrical activity travels to base of ventricles via bundle of His
- Electrical activities spread across the surface via purkyne fibres
7.Ventricles contract from the base upward
What is an electrocardiogram?
The reading of a single heartbeat
What do the features of an ECG mean?
Small bump at the start- Atrial systole
Small dip then big increase and dip again- Ventricular systole
Small bump at the end- Diastole
What is tachycardia?
Heart rate over 100 bpm
What is bradycardia?
Heart rate below 60 bpm
What is an ectopic heart beat?
Extra heart beats out of normal rhythm
What is atrial fibrillation?
The atria contract very fast but not properly and ventricles contract less often
What are the features of atrial systole?
Atria contract simultaneously
Forces remaining blood from atria into ventricles
AV valves close
What are the features of ventricular systole?
AV and SL valves closed
Ventricles contract from base upwards
Blood forced out of aorta and pulmonary artery
SL valves open
What is a double circulatory system?
- Two separate circuits
- Blood passes through heart twice
- Second circuit is between heart and lungs (pulmonary circulation)
