B.4 organisation in us Flashcards
what does plasma transport
to transport substances around the body via blood
eg
-nutrients, oxygen and amino acids
-waste products, carbon dioxide +urea
-hormones, antibodies
what make up the human circulatory system
-blood
-blood vessels
-heart
state what red blood cells contain
-haemoglobin that binds to oxygen to transport it from the lungs to tissues
how do white blood cells help the body
-prevent it from infection
state what platelets do
-cell fragments that start clotting process at wound sites
what actually makes blood red
haemoglobin
what are platelets
Cell fragments that start the clotting process at wounds.
What are the capillaries there for?
Substances diffuse in and out of the blood
What kind of circulatory system do humans have?
A double circulatory system
What do stents do?
Keep narrowed or blocked arteries open.
What do statins do?
Reduce cholesterol levels reducing the risk of coronary heart disease.
the heart has ..
how can damaged heart valves be replaced
-biological valves
-mechanical valves
What is the resting heart rate controlled by?
A group of cells in the right atrium form a natural pacemaker.
What are artificial pacemakers used for?
They’re used to correct irregularities in the heart rhythm.
What are artificial hearts used for?
Keep patients alive while they wait for a transplant or to allow their own heart to rest.
what are the lungs protected by
ribcage
What do the alveoli do?
Provide a large surface area and a rich supply of blood capillaries, so gas can diffuse efficiently.
state how arteries are adapted to their function
-thick walls
-contain layers of muscle to make them strong
-elastic fibres to allow them to stretch and spring back
how are capillaries adapted to its function
-permeable walls so substances can diffuse in and out
-walls are only 1cell thick, increasing rate of diffusion
how are veins adapted to their function
-bigger lumen than arteries to help blood flow despite the lower pressure
how are red blood cells adapted
-biconcave disc (gives a large surface area for absorbing oxygen)
-no nucleus, more room to carry oxygen
how are white blood cells adapted
contain a nucleus (to defend the body against infection and disease)
