The Circulatory System:
Functions
How does it work?
Heart:
When the muscle contracts (Systole) it pushes blood around the circulatory system.
When the muscle relaxes (Diastole) it absorbs blood from the circulatory system
It is a muscle that contracts and relaxes.
Composed by: heart (pump), blood vessels (conduit), and blood (circulating material).
It pumps blood from the heart to the lungs to get oxygen. The heart then sends oxygenated blood through arteries to the rest of the body. The veins carry oxygen-poor blood back to the heart to start the circulation process over.
It transports subtances: Nutrients, antibodies, hormones, oxygen.
Blood vessels:
Capillaries
Arteries
Veins
Carry oxygenated blood from the heart to the body
are the smallest blood vessels and take the blood to every cell in an organ
Blood:
Body –>
Inferior/superior vena cava –>
Right atrium –>
Tricuspid valve –>
Right ventricle –>
Pulmonary arteries –>
carry deoxygenated blood from the body to the heart
Lungs –>
Pulmonary veins –>
Left atrium –>
Mitral or bicuspid valve –>
Left ventricle –>
Aortic valve –>
Aorta –>
Body.
carry high-pressure blood away from the heart to tissues that need it.
Systole + Diastole = HEART BEAT
Are very small and therefore can penetrate virtually every tissue in the body. Blood moves slowly through them under low pressure providing opportunities for the exchange of substances.
carry the low pressure blood back to the heart using valves to ensure blood flows in the correct direction
Blood:
Two distinct locations for blood transport:
The left side of the heart pumps oxygenated blood around the body (systemic circulation)
The right side of the heart pumps deoxygenated blood to the lungs (pulmonary circulation)
How does the blood transport gases?
The left side of the heart will have a much thicker muscular wall (myocardium) as it must pump blood much further
Biconcave disk shape (more flexibility)
No nucleus or mitochondria (extra room)
Full of haemoglobin (protein which binds to O2)