Circulation system Flashcards
what is the purpose of the circulatory system?
carries oxygen and other useful substances to the bodily tissues and removes waste substances
explain how the double circulatory system works
Deoxygentaed blood from the vena cava will enter the body, filling the right atria
Oxygenated blood from the pulmonary vein will fill the left atria
Both atria contract which makes the blood fill up the left and right ventricles
The ventricles will contract leading the deoxygenated blood too go through the pulmonary artery and oxygenated blood to go through the aorta to the rest of the entire body
Why is the double circulatory system efficent?
it makes the circulatory system more efficient as blood can be pumped around at higher pressure
why is the left wall of the heart more muscular then the right?
This left ventricle carrys blood at much higher pressure
as it has to go round the entire body
Why are the valves needed?
Stops blood flowing backwards
what are the four main blood vessels that transport blood around the heart?
Vena cava = deoxygenated blood from the body to the right atria
Pulmonary vein= brings oxygenated blood from the lungs to the left atria
Pulmonary artery= brings blood from the right ventricle to the lungs
aorta = brings oxygented blood from the left ventricle to all around the body
What are the function of the coronary arteries?
They supply the heart with it’s own source of oxygenated blood, they branch off the aorta and surrond the heart
what is used when the normal pacemaker cells don’t work?
pacemaker cells create a small electric pulse causing the heart muscle’s to contract
Usually a mechanical pacemaker is used to control an irregular heart beat
Name the 3 types of blood vessels
Arteries, veins and capillaries
How are arteries adapted for there function?
The heart pumps blood in the ateries at high pressure so the walls are thick and elastic
Large walls compared to lumen
thick layers of muslce with elastic fibres to allow them to stretch
How are veins adapted for there functions?
Blood is at lower pressure in the veins in the veins so the walls are not as thick
they have a bigger lumen to help the blood flow
they also have valves to stop the backflow of blood since it is not at high pressure
Why is the double circulatory system efficent?
It means the oxygented blood can be pushed out of the left ventricle at a higher pressure while deoxygneted blood can be pumped to the lungs at the same time
How is the heart beat controlled?
With pacemaker cells found in the right atrium which relase an electric current to heart muscles forcing it to contract
How are abnormal heart beats controlled?
Irregular heart beats are controlled by an artifical pacemaker which will send an electric current to the heart
How are capillaries adapted for there function?
one cell wall thick so short diffusion path
permarble walls substances can easily diffuse across
narrow lumen slows down the pressure leaving more time for tissues to perfom gas exchange
How would you calculate the rate of blood flow?
volume of blood/number of minutes
2.175 ml of blood travelled through a vein in 8.7 mintutes calcutate the rate of blood flow
250ml/min
why would a vein stretch more easily compared to an artery?
vein has fewer muscles fibers compared to an artery
Where are the lungs located?
Lungs are located in the thorax, protected by the intercostal muscles and ribcage. It’s seperate from the lower part of your body by the diaphragm
Which tissues make up the gas exchange system?
Trachea
intercostal muscles
bronchi
bronchioles
alveoli
diaphragm
Describe how the intercostal muscles help the lungs to ventilate (exhalation and inhalation)
Intercostal muscles will contract
Leading the ribs to move up and out
the diaphragm will flatten
this will leave a large space increasing the volume of the lungs
Increased volume = decreased pressure
Air is drawn into the lungs to even the pressure gradient
Describe how gas exchange occurs at the alveoli
Oxygen in the alveoli diffuses into the cappilary bloodstram, as it is is low in oxygen the oxygen will be drawn in
carbon dioxide in the blood will go towards the low graident which is in the alveli
How are alveoli adapted for gas exchange?
Small and plentiful gives a large surface area
Rich blood supply maintains the concentration gradient, oxygen is quickly moved away to keep the concentration low
thin alveoliar walls maintains a short pathway
How would you calculate the breath rate?
number of breaths / number of mintutes
what substances are transported by the plasma?
red blood cells
white blood cells
platlets
urea
products of digestion
how are red blood cells adapted for there function?
Biconcave shape- increased surface area to volume ratio
no nucleus which allows more room for oxygen to be transported
Contains hamoglobin which allows it to bind to oxygen
How are white blood cells adapted for there function?
Has DNA which codes for protiens
can produce antibodies
can produce antitoxins
Perform phagocytosis
Purpose of platelets
Platlets are small cell fragments which help to scab wounds
why are platlets important?
Platlets aid in the perfomance of blood clotting which is the conversion of fibrinogen to fibrin , all blood cells are in the fibrin network to prevent excessive bleeding
Explain how the presence of cholestrol in the coronary arteries can affect oxygen delivery to the heart muscles
Cholestrol will narrow the lumen which means lower blood flow
this restricts oxygen to the heart
Suggests and describe two types of replacement valves
Mechnanical - these are man made
biological- valves taken from another human or animal
why are statins sometimes used in the treatment of CVD?
Slows down the rate of cholestrol building up
which reduces the chances of coronary heart disease
