Cardiovascular System Flashcards
What does the circulatory system consist of? (3)
Heart
Blood vessels
Blood
What kind of circulatory system is in humans?
A closed system used to transport essential food, oxygen, nutrients and water to the cells of the body.
What does a closed circulatory system mean? (3)
The transport medium (blood) is contained in blood vessels and is not in direct contact with tissues.
The medium is under pressure as it is pumped around the body and returns directly to the heart.
This maintains pressure of the blood and ensures blood flows faster and blood flow can be directed.
What is the structure d the heart? (4)
It is hollow
Come-shaped muscular organ
Apex is at the bottom
Base is at the top
What is the position of the heart? (3)
Lies in the mediastinum of the thoracic cavity
Lies posteriorly to the sternum and between the lungs
Lies at an oblique angle, two thirds of which lie to the left of the bodies midline
Where is the apex of the heart positioned?
It is about 9cm to the left of the midline at the level of the 5th intercostal space
Where is the base of the heart positioned?
It extends to the 2nd rib.
What organ is inferiorly associated with the heart?
Diaphragm
What organ is associated superiorly to the heart? (4)
Aorta
Superior vena cava
Pulmonary artery
Pulmonary veins
What organ is laterally associated with the heart?
Lungs
What organs are located posteriorly to the heart? (6)
Oesophagus
Trachea
Left and right bronchus
Descending aorta
Inferior vena cava
Thoracic vertebrae
What organs are located anteriorly to the heart? (3)
Sternum
Ribs
Intercostal muscles
What are the three layers (structure) of the heart?
Pericardium (outer layer)
Myocardium (middle layer)
Endocardium (inner layer)
What is the purpose of serous fluid in the heart?
Lubrication
Allows layers to slide over eachother during each pump of the heart
What is the outer pericardium also known as?
Heart sac
What is the pericardium?
It is the outermost layer of the heart
Outer sac is fibrous
Inner sac is double layer of serous membrane
What is the two key characteristics of the outer fibrous sac of the pericardium?
It is continuous with the tunica adventitia (extra coat) of the blood vessels
Attached to the diaphragm below
What is the tunica externa?
It is the coating on the outer surface of the blood vessels
What is the tunica intima?
The most inner region of a blood vessel
Has endothelium, subendothelial layer was internal elastic lamina
What is tunica media?
The middle of the blood vessel, in between the tunica intima and tunica externa.
Has external elastic lamina
What is the purpose of an outer fibrous sac of the pericardium?
Prevents over-distension of the heart
What is the inner layer of the pericardium and explain the outer layer and how they both work? (4)
It consists of a double serous membrane
Outer layer is called the parietal pericardium and lines the fibrous sac
The inner layer is called the visceral pericardium and is adherent (attached) to the heart muscles
There is a potential space in between these that contain serous fluid and prevents friction
What lines the fibrous sac of the pericardium?
Parietal pericardium (outer layer)
What is adherent (attached) to the heart muscle?
Visceral pericardium (inner layer)
What is the pericardium?
It is the membrane enclosing the heart, consisting of an outer fibrous layer and an inner double layer of serous membrane
What is the myocardium composed of? (2)
Specialised cardiac muscle found only in the heart
It is striated and is not under voluntary control