Cardiovascular System Flashcards
Heart
• The heart is a pump that pushes the blood through the blood vessels of the CV system.
Septum (Parts of the Heart)
The Muscle that separates the left and right side of the heart
Apex (Parts of the Heart)
Lowest point of heart muscle
Atria (Both Atriums) (Parts of the Heart)
Upper chambers that receive blood, then push it into the ventricles
Left Atrium receives blood from the lungs
Right Atrium receives blood from the body
Ventricles (Parts of the Heart)
Lower chambers that pump blood out to different area of the body
Left ventricle pushes blood to the body
Right ventricle pushes blood to the lungs
Valves (Parts of the Heart)
There are 4 valves in the heart, to prevent the backflow of blood:
Bicuspid valve: Between left atrium and ventricle
Tricuspid valve: Between right atrium and ventricle
Semilunar Valves: Prevent backflow from arteries into ventricles for both sides of the heart
Papillary Muscle (Parts of the Heart)
Control the opening and closing of the valves
Chordae Tendineae (Parts of the Heart)
Connect the papillary muscles to the valves
Blood Vessels (Parts of the Heart)
There are 4 major grounds of blood vessels, entering and exiting the heart.
Superior vena cava: Major vein bringing blood into the right atrium from the head and upper body
Inferior vena cava: Major vein bringing blood into the right atrium from the lower body and legs
Pulmonary artery: Takes blood from the right ventricle to the lungs to remove C02 and gain O2
Pulmonary veins: Takes blood from the lungs to the left Atrium
Aorta
Delivers oxygen rich blood from the left ventricle to the rest of the body
Cardiac Cycle
The sequence of events that occur in the heart during 1 heartbeat
Parts to the Cardiac Cycle:
1. Atrial and ventricular diastole: all chambers are relaxed and are filling up with blood
2. Atrial systole: both atria contract, forcing the blood into the ventricles. (Ventricles still in diastole)
3. Ventricular systole: both ventricles contract, forcing the blood out of the heart. (Atria back in diastole)
• Cardiac cycle is driven by nerve impulses from the brain to the SA node (Sino-atrial node) which is the ‘pacemaker’ of the heart.
• This causes atrial systole
• The impulse is transferred through to the AV node (atrio-ventricular node) and then down the septum along the Perjinke fibres at the apex, which causes ventricular systole
Blood Vessels
• Once blood leaves the heart it travels through blood vessels, branching off in different directions and decreasing in diameter until the gases, nutrients and wastes can be exchanged at the cells.
• Then is directed back to the heart through vessels increasing in diameter as they collect together until they end back at the heart.
Blood vessels are divided into the following groups:
• Arteries
• Arterioles
• Capillaries
• Venules
• Veins
Arteries
• Thick elastic, muscular walls
• Muscular walls are important in directing blood flow around the body
• Small lumen
• Carry blood away from the heart
• Flood pressure is high but will fluctuate
• No valves
Arterioles
• Extends from arteries and leads to capillaries
• Small diameter
• Higher BP and Consistent
Capillaries
• Microscopic blood vessels
• Walls that are only 1 cell thick
• Forces the blood cells to pass through in single file
• This increases the BP even higher and slows down the rate/speed at which the blood passes through
• Both of these allow for an increase in the rate of diffusion/exchange can take place into the tissue/extracellular fluid