Cardiovascular System Flashcards
What is meant by double circulation?
Blood passes through the heart twice in one complete circuit
What are the two types of circulation\?
Pulmonary Circulation
Systemic Circulation
What takes place in the pulmonary circulation?
Deoxygenated blood through right ventricle - pulmonary artery - lungs where it is oxygenated
What takes place in the systemic circulation?
Oxygenated blood into left atrium - left ventricle - aorta - the rest of the body
Why is the pulmonary circulation pressure lower than the systemic circulation?
This is due to the difference in the thickness of the heart muscle in the ventricles
Ventricles contract from bottom up
What is the difference between the right and left ventricle?
Left Ventricle - thicker and stronger muscular wall
What blood vessel carries deoxygenated blood back to the heart?
Vena Cava
What blood vessel carries oxygenated blood to the rest of the body?
Aorta
What are the three main types of blood vessel?
Veins
Arteries
Capillaries
Describe 3 characteristics of arteries
Thick wall of smooth muscle
Small/ narrow lumen
Numerous elastic fibres
What is an arteries main role?
To carry blood away from the heart
Where are arteries situated?
Deep inside the body
Why do arteries have a narrow lumen?
To maintain high pressure and speed at all times
Describe what the smooth muscle in the artery allows for:
Vasodilation
Vasoconstriction
What is a veins main role?
To carry blood into the heart
What are 3 characteristics of veins?
Large/ wide lumen
Thinner wall of smooth muscle
Contains valves
Why do veins contain valves?
To prevent the backflow of blood
What is the name for the veins that have been branched off from large veins?
Venules
What is the name for the smaller form of arteries?
Arterioles
What are capillaries main role?
Contain a large surface area for exchange to take place
What are 2 characteristics of capillaries?
One cell thick
Permeable to water and other molecules - nutrients, oxygen can pass through (remove waste products)
What are the 4 main chambers of the heart?
Right Atrium
Left Atrium
Right Ventricle
Left Ventricle
What are the 4 main valves?
Tricuspid Valve (Atrioventricular Valves) Bicuspid Valve
Pulmonary Valve (Semilunar Valves) Aortic Valve
What is the heart?
The heart is myogenic
What is meant by myogenic?
It does not rely on the nervous system for stimulation
What are the 3 stages of the cardiac cycle?
Atrial Systole
Ventricular Systole
Diastole
What are the 4 parts of the heart involved in heart stimulation?
Sinoatrial Node
Atrioventricular Node
Bundle of His
Purkinje Fibres
What is the SA node also known as?
The hearts pacemaker
What is atrial systole?
The atria contract - blood is pushed into the ventricle
What is ventricular Systole?
Ventricles contract - push blood into the aorta and to the rest of the body
What is diastole?
The heart chambers relax - blood flows into the heart
What causes the first heart sound?
The atrioventricular valves closing (tricuspid & bicuspid valves)
What causes the second heart sound?
The semilunar valves closing (pulmonary & aortic valves)
What causes valves to close?
Atrioventricular valves close when - ventricle pressure is higher than atrial pressure
Semilunar valves close when - ventricle pressure is higher than atrial pressure
Name 4 of the main factors affecting heart rate:
Age
Gender
Emotional state
Temperature
What causes thrombosis to occur?
Blood clots and blocks a blood vessel
What are the 2 types of thrombosis?
Venous thrombosis (clot blocks a vein)
Arterial thrombosis (clot blocks an artery)
What is CHD?
Coronary Heart Disease
Stages of blood clotting - stage 1
Clotting factors are attracted to the injury
Stage 2 of blood clotting
Prothrombin (inactive enzyme) is converted into thrombin (active)
Stage 3 of blood clotting:
Thrombin (active) converts fibrinogen (soluble) into fibrin (insoluble)
3 stages of blood clotting:
Damaged blood vessels - triggers release of clotting factors
Formation of a platelet plug
Fibrin strands form an insoluble clot
How is the structure of valves important in allowing them to open/ close?
They contain chordae tendinea (heart strings) allows them to slam shut
Describe the structure of haemoglobin:
4 polypeptide chains - quaternary structure
What sort of a protein is haemoglobin?
Conjugated protein
What is the prosthetic group found in haemoglobin?
haem (iron)
How many haem groups does each haemoglobin molecule contain?
4 haem groups
How much oxygen can one haem group transport?
One oxygen molecule per haem group
How do ventricles contract?
Ventricles contract from the bottom up
Why do ventricles contract from the bottom?
To ensure all the blood is squeezed out , so the blood is pushed up and out through the semilunar valves
Why is there a slight delay in the contraction of the atrium and ventricle?
The ventricular systole pressure builds up causing the pressure to increase and the valves to slam shut and blood to then move into the semilunar valves
How is the heart myogenic?
It does not rely on the nervous system to contract
3 advantages of the bohr effect:
