4.2.2.2 The Heart and Blood Vessels Flashcards
Where is the thorax?
- at the top part of the body
What is the thorax separated by?
- diaphragm
What are the lungs protected and surrounded by?
- ribcage
- pleural membranes
Where does gas exchange happen in the lungs?
- alveoli surrounded by a network of blood capillaries
What happens when blood passes next to the alveoli from the lung?
- oxygen diffuses out of the alveolus (high concentration) into blood (low concentration)
- carbon dioxide diffuses out of the blood (high concentration) into alveolus (low concentration) to be breathed out
What happens when the blood reaches body cells?
- oxygen is released from red blood cells (high concentration) and diffuses into body cells (low concentration)
- carbon dioxide diffuses out of the body cells (high concentration) and into blood (low concentration) to be carried back to the lungs
How do you calculate breaths per minute/breathing rate?
- breaths per minute = number of breaths / number of minutes
What is the circulatory system made up of?
- heart
- blood vessels
- blood
What is the double circulatory system?
- two circuits joined together
What is in the first system of the double circulatory system?
- right ventricle pumps deoxygenated blood to the lungs to take in oxygen
- blood then returns to the heart
What is the second system of the double circulatory system?
- left ventricle pumps oxygenated blood around all the other organs of the body
- the blood gives up its oxygen at the body cells and deoxygenated blood returns to the heart to be pumped out of the lungs again
What are the heart walls mostly made of?
- muscle tissue
What do the valves prevent?
- blood flowing backwards
- make sure blood flows in right direction
What are the four chambers of the heart?
- right atrium
- right ventricle
- left atrium
- left ventricle
How does the heart pump blood around the body?
- blood flows into atria from vena cava and pulmonary vein
- atria contract which pushes blood into ventricles
- ventricles contract which forces blood into pulmonary artery and aorta and out of the heart
- blood flows to organs through arteries and returns through veins
- then repeat
What are coronary arteries?
- arteries that branch off of the aorta and surround the heart
- makes sure the heart has its own supply of oxygenated blood
What is a pacemaker?
- group of cells in the right atrium that control resting heart rate
What do the cells that make up a pacemaker do?
- produce small electric impulse which spread to surrounding muscle cells which cause them to contract
What is an artificial pacemaker often used for and what is it?
- controlling heartbeat if natural pacemaker cells don’t work properly
- a little device implanted under skin and has a wire going to heart, producing electric current to keep heart beating regularly
What is the function of the arteries?
- carry blood away from the heart
What is the function of the capillaries?
- involved in the exchange of materials at the tissues
What is the function of the veins?
- carry blood to the heart
What are the adaptations of the arteries?
- strong and elastic walls to pump blood out at high pressures
- thick walls compared to size of lumen
- contain thick layers of muscle to make them strong and elastic fibres to allow them to stretch and spring back
- branch into capillaries
What are the adaptations of the capillaries?
- too small to see
- carry blood really close to every cell to exchange substances
- permeable walls so substances can diffuse
- supply food and oxygen and takes away carbon dioxide
- walls are only one cell thick which increases rate of diffusion by decreasing distance
- join up to form veins
