The Cardiovascular System Flashcards
What is the pulmonary circuit?
The pulmonary circuit refers to the network of blood vessels that connect the heart and the lungs.
Allows deoxygenated blood to be pumped to the lungs to ‘drop off’ metabolic waste products and to be oxygenated and returned to the heart.
What is alveolar gas exchange?
Where waste products diffuse from the blood into the alveoli and oxygen diffuses from the lungs into the blood.
What is the heart?
The cardiovascular system’s pump. It is what causes blood to move around the body.
It does this by creating pressure gradients
What are blood vessels?
There are many blood vessels in the body. The function of the blood vessels is to transport blood.
This is because blood carries nutrients, gases, metabolic waste products, hormones which are essential for life.
What is the systemic circuit?
A network of blood vessels that connect the heart of the body.
These blood vessels allow transportation of oxygenated blood to all of body tissues where peripheral gas exchange occurs
What is peripheral gas exchange?
Where oxygenated diffuses from the blood into the tissues where it is needed for cellular respiration to create energy.
Metabolic waste products diffuse from the tissues into the blood to be transported back to the heart and lungs for removal
Where is the heart located?
The heart is located in an area known as the mediastinum - behind the sternum and angled slightly to the anatomical left.
What is the pericardium?
Tough connective tissue that surrounds the heart
What are the two layers of the pericardium?
Fibrous pericardium
Serous pericardium
What are the functions of the pericardium?
- Protect the heart
- Anchor the heart in position
- Prevent overfilling of the heart with blood
- Provide a ‘friction-free’ environment when the heart beats
What are the 3 layers of the heart?
Epicardium
Myocardium
Endocardium
What is the epicardium?
The outermost layer of the heart wall
What is the myocardium?
The middle layer of the heart, it is the muscular layer made up of cardiac muscle
What is the endocardium?
The innermost layer of the heart.
Made up of simple squamous epithelium
What are the 4 chambers of the heart?
Right atrium
Right ventricle
Left atrium
Left ventricle
What are the ventricles of the heart separated by?
Interventricular septum
What is the atria (atrium)
The heart’s receiving chamber. They receive blood returning to the heart from the body (right atrium) and from the lungs (left atrium)
What are ventricles?
The heart’s dispensing chambers - when the heart muscle contracts, they pump the blood out of the heart to the lungs or to the rest of the body
What are the superior and inferior vena cava
The major blood veins returning blood to the heart from the body
What is the pulmonary artery?
An artery which blood flows out of (the heart) and to the lungs via the pulmonary artery
What are the pulmonary veins?
Blood returns to the heart from the lungs via (four) pulmonary veins
What is the aorta?
Part of the heart that finally expels the blood from the heart to the rest of the body.
What valves separate the different chambers of the heart?
Atrioventricular valves
Right - tricuspid valve
Left - bicuspid valve
Describe the tricuspid valve (right atrioventricular valve)
Made up of 3 individual leaflets, or cusps, which open and shut together to allow or restrict blood flow between these chambers
Describe the bicuspid valve (left atrioventricular valve)
Made up of 2 individual leaflets, or cusps, which open and shut together to allow or restrict blood flow between these chambers
What are the 2 valves that separate the ventricles from the large arteries leaving the heart?
Aortic semilunar valve
Pulmonary semilunar valve
Thinking of the flow of blood through the heart, what’s one difference between an artery and a vein?
Arteries always take blood away from the heart.
Veins always return blood to the heart.
What’s an easy way to remember which side of the heart the tricuspid valves and bicuspid valves are located?
Use the acronym LAB RAT
Left Atrium - Bicusid
Right Atrium - Tricuspid
Thinking of the pulmonary and systemic circulations, which do you think pumps blood under the highest pressure and why?
The systemic circuit pumps blood under the highest pressure as it needs to ensure that blood reaches to the top of your head and tips of your toes.
The pulmonary circuit is shorter and the less structure of the vasculature means less pressure is generated in this system.
What is the function of valves?
Valves prevent the backflow of blood.
They open and close in response to pressure changes within the chambers and/or arteries leaving the heart, and they ensure unidirectional blood flow through the heart.
Why is the backflow of blood a bad thing?
If blood were able to flow backwards, blood would not be expelled from the heart to the body effectively, meaning that vital nutrients would not be supplied to the tissues.
It would also cause a backlog of blood in the system, which is bad news!
What are arteries?
Arteries are thick walled and carry large volumes of blood away from the heart.
What are capillaries?
Capillary networks is where gas exchange occurs between the tissues and the blood
Name 3 structural parts of blood vessels.
Tunica intima
Tunica Media
Tunica externa
Describe the tunica intima.
The inner layer.
Made up of simple squamous epithelia, providing a smooth surface for blood flow.
Describe the tunica media.
The middle layer.
Made up of smooth muscle and elastic fibres, giving flexibility allowing the vessel to expand under pressure.
Describe the tunica externa
The outer layer.
Connective tissue rich in collagen, proving it strength and holds the vessels together
Name the types of blood vessels.
Arteries
Arterioles
Capillaries
Veins
Describe the differences between arteries and veins
Arteries carry blood away from heart. Veins carry to.
Arteries carry blood under high pressure. Veins are low.
Arteries have a narrow lumen, veins have a wide lumen.
What are 4 ways blood can return to the heart?
Pressure
Valves
Skeletal muscle pump
Respiratory pump
What is pulse?
The pressure wave felt in an artery that lies close to the surface of the body.
The pressure wave is a result of the left ventricle contracting.
Why does blood not flow back towards the abdominal cavity?
Valves prevent backflow of blood in the veins and at the same time, large veins are ‘squeezed’ by contracting expiratory muscles so that blood is pushed towards the heart.
How does the heart get nourishment?
The heart gains oxygen and nutrients from the blood via the coronary arteries
What is the coronary sinus?
Venus blood is collected by the cardiac veins which join to form the coronary sinus.
Empties blood into the right atrium.
Name the 3 large tributaries of the coronary sinus?
Great cardiac vein
Middle cardiac vein
Small cardiac vein
