Chapter 16- Cardiovascular system 1 Part 1 (1) Flashcards
What does the cardiovascular system consist of?
Heart and blood vessels
How much does the heart roughly weigh?
300 grams
Where is the heart located?
Within the mediastinum- a cavity inside the thorax.
What is the heart covered by?
A double waled sac called the pericardium
The pericardium has two layers:
1- Fibrous pericardium- the layer on the surface which is made up of connective tissue. It protects the heart and anchors it in place.
2- Serous pericardium- a deep layer which is a thin, slippery membrane.
- This is composed of two layers, each made up of simple squamous epithelial cells.
- Between them is a cavity which contains a serous fluid that acts as a lubricant, allowing the two layers to glide past each other.
Inflammation of the pericardium can cause what?
Pain and shortness of breath.
What will excessive fluid in the pericardial cavity cause?
It can put pressure on the heart, preventing the ventricles from filling.
The heart wall is composed of 3 layers:
1- Epicardium- the bottom layer of the pericardium. Often contains fat.
2- Myocardium- where the cardiac muscle tissue resides
3- Endocardium- a squamous epithelium which lines the heart chambers.
How many chambers does the heart contain?
4
What do the chambers in the heart consist of?
Consists of the 2 superior atria- the left and right atrium
Consists of the 2 inferior ventricles- the right and left ventricles
What does the left atrium do?
Receives oxygen rich blood from the lung, via 4 pulmonary veins.
From here, the oxygenated blood travels down to the left ventricle.
What does the left ventricle do?
Pumps oxygenated blood out around the body, via the aorta.
The left ventricle is the driving force for what circuit?
The systematic circuit
Why is the left ventricle more well developed than the right ventricle?
Because it pumps oxygenated blood around the body.
How is the left ventricle more well developed than the right ventricle?
It has thicker walls and has much more myocytes
What branches off the aorta?
The right and left coronary arteries.
What do the right and left coronary arteries do?
These supply the heart muscle itself with blood
What does the right atrium do?
Receives deoxygenated blood via 3 veins.
Two of the veins bring back deoxygenated blood from around the body. They are the inferior and superior vena cava.
The third vein collects blood from the myocardium itself. This is called the coronary sinus.
From here, the deoxygenated blood then travels down to the right ventricle.
What does the right ventricle do?
Pumps deoxygenated blood back to the lungs via the pulmonary trunk.
It is smaller and weaker than the left ventricle.
The right ventricle is the driving force for what circuit?
The pulmonary circuit
What is the function of valves?
They are mechanical devices that open and close in response to differences in blood pressure.
What do valves ensure?
Valves ensure that blood only flows in one direction
There are two main types of valves in the heart:
1- Atrioventricular valves (AV)
2- Semilunar valves
