Circulatory System Flashcards
Where do open circulatory systems occur
Arthropods including insects
How do open circulatory systems work
The heart is a simple tube with Valves
Valves pump blood into opening at back of the animal and out the front
Blood fills the haemocoel, bathing internal organs
Where are closed blood systems found
Earthworms and vertebrate animals
How does a closed blood system work
Blood pumped from heart in vessels
Stays in vessels always
Larger arteries divide to capillaries which supple 02 and nutrients and get rid of co2 and waste
Capillaries join into veins to carry blood back to heart
BP is higher in closed blood system = more efficient and vertebrate can be larger
What are the two circulatory circuits that exist in human circulatory system
Pulmonary circulatory system
Systemic circulatory system
What is the structure of the heart
Walls of heart = cardiac muscle
Double membrane enclosing heart = pericardium
Fluid between pericardial membranes = reduce friction
02 and nutrients supplied by carotid arteries divided in half by septum
What is the basic function of the valves in the heart
Allows for efficient blood flow by making sure there is no back flow of blood and blood moves in one direction
What are the names of the valves found in the heart
Bicuspid / Mitral valve, tricuspid valve, pulmonary valve and aortic valve
What is the importance of the atrioventricular valves
Lie between atrium and ventricle
Can have 2 or 3 flaps
Inelastic tendons stop ventricle from turning upside down
What is the importance of the semilunar valve
Open to allow blood out ; close to prevent it from returning during contraction and relaxation of ventricles
What are the phases of the cardiac cycle, how long is each phase
Atrial systole - 0.1s
Ventricular systole - 0.3s
General diastole - 0.4s
What is the cardiac cycle
Everything that your heart does in one heartbeat
What happens during atrial systole (and ventricular diastole)
Atria full with blood And contract simultaneously
Atrioventricular valves are forced open and blood flows to ventricles
What happens during ventricular systole (atriole diastole)
Ventricles contract simultaneously
Back pressure of blood forces atrioventricular valves to close
Blood moves to aorta and pulmonary arteries under pressure
What happens during general diastole
Ventricles and atria relax
Residual pressure forces blood to fill atria
Why does the left side of the heart have thicker muscle walls than the right
Has to pump blood to the rest of the body = long distance = more force is needed
How is our heartbeat controlled
Sino-atrial node initiates heartbeat using impulses
Impulses spread to atria causing contraction
Impulse spread to atrioventricular node and down bundle of hiss
Impulse Travels up purkinje fibres = ventricles contract bottom up effectively getting blood out of heart
Ions replenish themselves so they can pump blood again
What is the dino-atrial node also known as
Pacemaker of heart
How does exercise affect the heart
Heartbeat increases to get more O2 to cells + get rid of CO2
Carotid arteries detect increase in Co2 and send impulses to brain
Autonomic nervous system controls heart rate via sympathetic and parasympathetic nerves
Hormones adrenaline (increase heart rate) and thyroxine(increase metabolism) produced during exercise or stress
What are normal heart rates for a healthy ;person
Resting - 60-90 bpm
Max heart rate - 150-200 bpm
Why donhealthier / fitter people have a lower heart rate
The heart is stronger so it can pump more blood in one beat (pump more blood using less energy)