Heart Flashcards
Name the 2 types of circulation
Pulmonary circulation
Systemic circulation
What is Pulmonary circulation?
The heart pumps deoxygenated blood to the lungs
What is Systemic circulation?
The heart pumps oxygenated blood to the body
Name the progression of oxegen transfer through the blood vessels.
Arteries - Aterioles - Capillaries - Venules - Veins
How much does the heart weigh in males and females?
250g in females
300g in males
Name the layers of the Pericardium
Fibrous pericardium
Serous pericardium
How many layers does the Serous pericardium have?
2
Name the layers of the Serous percardium
Parietal layer (Outer layer) Visceral layer (Inner layer)
Name the layers of the heart wall and pericardium in order (Start with Innermost layer)
Endocardium Myocardium Epicardium (or viceral layer) Serous fluid Parietal layer Fibrous pericardium
How many ml of pericardial serous fluid lies between the Parietal layer and Viceral layer?
20ml
Does the viceral layer also form part of the heart wall?
Yes
What 4 functions does the pericardium have?
- Prevents over-distension (i.e. over filling of the chambers)
- Anchors the heart in place
- Protection from infection
- Lubrication
What’s the name of the mussle which seperates the heart into TWO halves?
Septum
What’s the septum made out of?
Myocardium and a lining of endothelium
Where are papillary muscles found and what’s there role?
Found in the heart
When the muscles contract they stop the artioventricular valves opening by tightening the chordae tendinae.
How many pulmonary veins are there in total?
4 (2 to each lung)
How do valves within the heart open?
Increased pressure of blood
What does the chordae tendinae do?
Stop the valve from opening upwards into the atrium
What’s the name of the hearts own blood circulation system?
Coronary circulation
What percentage of blood does the heart recieve?
Receive about 5% of the blood from the heart
Name the coronary branches on the left side of the heart
Left coronary artery Circumflex artery Left marginal artery left anterior descending artery Diagonal arteries
Name the coronary branches on the right side of the heart
Right coronary artery
Right marginal artery
What artery supplies the left and right ventricle?
Left anterior descending artery
What artery supplies blood to the left atrium and left ventricle?
Circumflex artery
What artery supplies blood to the right atrium?
Right coronary artery
What artery supplies blood to the right ventricle?
Right marginal artery
Where does the majority of the coronary veins drain into?
Coronary sinus
Where is the coronary sinus located?
Posterior surface of the right atrium
What is the coronary sinus?
A very thin walled vein which empties deoxegenated blood from around the heart back into the right atrium
What initiates electrical impulses which cause coordinated contractions of the heart?
A small bundle of specialised neuromuscular cells in the myocardium
Where is the Sinoatrial node (SA node) located?
Right atrium
What does the sinoatrial node (SA node) do?
Generates electrical impulses and sets the rhythm of the heart beat
Where is the Atrioventricular node (AV node) located?
Located in the wall of the atrial septum
How is an electrical impulse discharged?
Fibres in the myocardium are electrically unstable and constantly depolarise and repolarise.
When they depolarise they discharge an electrical impulse.
What’s the network of specialised cardiac muscle fibres found in the myocardium called?
Autorhythmic fibres
Do Autorhythmic fibres require a nervous system stimulation pulse to trigger contraction of the heart?
No Autorhythmic fibres are self-excitable
Describe the route of conduction through the heart
Sino Atrial node - (0.1s later) Atrioventricular node - Atrioventricular bundle (Bundle of His) - Divides into right and left branch down the ventricular septum - Purkinje fibres - continues along the walls of the ventricles.
