Heart And Circulatory System Flashcards
What type of system to mammals have
Closed double cirulatory system
Blood in vessels passes twice through the heart
Why do mammals have a doubel circulatory system
Keeps oxygenated and deoxygenated blood separate
Allows efficient supply of oxygen to body
What are the two types of systems
Open and closed
What is a closed circulatory system
Blood is pumped around the body and is always contained in a network of blood vessels
What is an open circulatory system
Blood is not contained within blood vessels but pumped directly into body cavities
What type of circulatory system to humans have
Closed
Double
Circulatory system
Describe the two circulatory systems in the heart
PULMONARY circulatory system = right side pumps deoxygenated blood to the lungs
SYSTEMATIC circulatory system = blood RETURNS from left side pumped to the body
Function of the heart
Hollow muscular organ located in the chest cavity whivh pumps blood
Cardiac muscle tissue specialised for repeated involuntary contraction without rest
Function of arteries
Blodo vessels carry oxygenated blood AWAY from heart
Walls of arterioles contain muscle and elastic tissue and a narrow lumen, to maintain high blood pressure
Function of arterioles
Small arteries which branch from larger arteries and connect to capillaries
Function of capillaries
Tiny blood vessel that connect arterioles and vanules
Size means they pass directly past cells and tissues and perform gas exchange and exchange of substances such as glucose
Function of venules
Small veins which join capillaries to larger veins
Function of veins
Blood vessels = carry blood back towards the heart
Walls = thin, having less muscle and elastic tissue but a wider lumen
Valves = maintain blood flow back towards the heart
How are contractions of heart muscles and volume related
Contraction of heart muscles = decrease in volume of corresponding heart chamber
Volume decreases = pressure increases
Volume increases = pressure decreases
How do valves affect the cardiac cycle
Heart valves open and close due to pressure changes in different heart regions
Valves open = pressure of blood behind greater than infront
Close when p in front is greater than behind
Name the two typ of systoles
Atrial systole
Ventricular systole
What happens when the atria walls contract
Atrial volume decreases
Atrial pressure increases
How do atrioventricular valves open
Pressure in the atria more than ventricles so forced to open
Blood is forced through
Ventricular pressure and volume increases as the ventricles receive blood from the atria
What happens when the ventricles contract
Ventricular volume decreases
Pressure increases
How do atrias close
Pressure in ventricles rises above pressure in atria
Forces atrioventricular valves to close preventing back flow
How do semi lunar valves open
Pressure in ventricles > aorta and pulmonary artery
Forces the semilunar valves open so blood is forced into the arteries out fo the heart
Name for when venticles and atria is relaxed
Ventricles = ventricular diastole
Atria = atrial diastole
Describe the whole cardiac cycle
1) Atrial systole, ventricular diastole = atria contract pushing blood into the ventricles
2) Atrial diastole, ventricular systole = after the atria relax, the ventricles contract pushing blood out of the heart
3) Cardiac diastole = all chambers relaxes and blood flows into hearrt
(Goes back to 1)
Describe the valves during atrial systole
Atrioventricular valves open
Semilunar valves closed
Blood flows in ventricle
