4.2.2.2 The Heart and Blood Vessels

Question 1

Where is the thorax?

Answer 1

• at the top part of the body

Question 2

What is the thorax separated by?

Answer 2

• diaphragm

Question 3

What are the lungs protected and surrounded by?

Answer 3

• ribcage
• pleural membranes

Question 4

Where does gas exchange happen in the lungs?

Answer 4

• alveoli surrounded by a network of blood capillaries

Question 5

What happens when blood passes next to the alveoli from the lung?

Answer 5

• 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

Question 6

What happens when the blood reaches body cells?

Answer 6

• 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

Question 7

How do you calculate breaths per minute/breathing rate?

Answer 7

• breaths per minute = number of breaths / number of minutes

Question 8

What is the circulatory system made up of?

Answer 8

• heart
• blood vessels
• blood

Question 9

What is the double circulatory system?

Answer 9

• two circuits joined together

Question 10

What is in the first system of the double circulatory system?

Answer 10

• right ventricle pumps deoxygenated blood to the lungs to take in oxygen
• blood then returns to the heart

Question 11

What is the second system of the double circulatory system?

Answer 11

• 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

Question 12

What are the heart walls mostly made of?

Answer 12

• muscle tissue

Question 13

What do the valves prevent?

Answer 13

• blood flowing backwards
• make sure blood flows in right direction

Question 14

What are the four chambers of the heart?

Answer 14

• right atrium
• right ventricle
• left atrium
• left ventricle

Question 15

How does the heart pump blood around the body?

Answer 15

• 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

Question 16

What are coronary arteries?

Answer 16

• arteries that branch off of the aorta and surround the heart
• makes sure the heart has its own supply of oxygenated blood

Question 17

What is a pacemaker?

Answer 17

• group of cells in the right atrium that control resting heart rate

Question 18

What do the cells that make up a pacemaker do?

Answer 18

• produce small electric impulse which spread to surrounding muscle cells which cause them to contract

Question 19

What is an artificial pacemaker often used for and what is it?

Answer 19

• 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

Question 20

What is the function of the arteries?

Answer 20

• carry blood away from the heart

Question 21

What is the function of the capillaries?

Answer 21

• involved in the exchange of materials at the tissues

Question 22

What is the function of the veins?

Answer 22

• carry blood to the heart

Question 23

What are the adaptations of the arteries?

Answer 23

• 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

Question 24

What are the adaptations of the capillaries?

Answer 24

• 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

Question 25

What are the adaptations of the veins?

Answer 25

• blood is at a lower pressure so don’t have thick walls
• bigger lumen to help blood flow
• have valves to keep blood flowing in right direction

Question 26

How do you calculate rate of blood flow?

Answer 26

• rate of blood flow = volume of blood / number of minutes