Organisation - the lungs and circulatory system

Question 1

what is the thorax and how is it separated
2 points

Answer 1

1) the top part of your body
2) separated form your lower body by the diaphragm

Question 2

explain how air travels in your body

Answer 2

1) the air that you breathe in goes through the trachea
2) it splits into two tubes called bronchi, one going into each lung
3) the bronchi splits into progressively smaller tubes called bronchioles
4) the bronchioles finally end at small bags called alveoli where the gas exchange takes place

Question 3

draw and label the lungs and stuff

Answer 3

look on page 56 of biology book

Question 4

where does gas exchange happen

Answer 4

in the alveoli

Question 5

what are alveoli surrounded by

Answer 5

blood capillaries

Question 6

explain how gas exchange works at the alveolus
3 points

Answer 6

1) the blood passing next to the alveolus contains lots of CO2 and very little O
2) the oxygen diffuses out of the
alveolus (high concentration) into the blood (low concentration)
3) carbon dioxide diffuses out of the blood (high concentration) into the alveolus (low concentration) to be breathed out

Question 7

draw and label gas exchange at an alveolus

Answer 7

look on page 57 of Bio book

Question 8

explain how gas exchange works at body cells
3 points

Answer 8

1) when the blood reaches the body cells oxygen is released from the red blood cells and diffuses into the body cells
2) at the same time, carbon dioxide diffuses out of the body cells into the blood
3) it’s then carried back to the lungs

Question 9

draw and label gas exchange at body cells

Answer 9

look on page 57 of bio book

Question 10

what is the circulatory system made up of
3 points

Answer 10

1) the heart
2) blood vessels
3) blood

Question 11

what kind of circulatory system do human have and what is this
2 points

Answer 11

1) we have a double circulatory system
2) this is two circuits joined together

Question 12

what happens in the first circuit of the circulatory system
2 points

Answer 12

1) the right ventricle pumps deoxygenated blood to the lungs to take in oxygen
2) the blood then returns to the heart

Question 13

what happens in the second circuit of the circulatory system
2 points

Answer 13

1) the left ventricle pumps oxygenated blood around all the other organs of the body
2) the blood gives up its oxygen at the body cells and deoxygenated blood returns to the heart to be pumped out to the lungs again

Question 14

what are the walls of the heart mostly made of

Answer 14

muscle tissue

Question 15

what do the valves of the heart do

Answer 15

they make sure blood flows in the right direction, prevent it from flowing backwards

Question 16

what are the four chambers of the heart
4 points

Answer 16

1) right atrium
2) left atrium
3) right ventricle
4) left ventricle

Question 17

draw and label the heart and its chambers

Answer 17

look on page 58 if bio book

Question 18

how does the heart use its four chambers to pump blood around the body
5 points

Answer 18

1) the blood flows into the two atria from the vena cava and the pulmonary vein
2) the atria contract, pushing the blood into the ventricles
3) the ventricles contract, forcing the blood into the pulmonary artery and the aorta, and out of the heart
4) the blood then flows to the organs through the arteries, and returns through veins
5) the atria fill again and the whole cycle starts over

Question 19

what do the coronary arteries do

Answer 19

1) the heart also needs its own supply of oxygenated blood
2) the coronary arteries branch off the aorta and surround the heart making sure it gets all the oxygenated blood it needs

Question 20

how is your resting heart rate controlled
2 points

Answer 20

1) by a group of cells in the right atrium wall that act as a pacemaker
2) these cells produce a small electric impulse which spreads to the surrounding muscle cells, causing the to contract

Question 21

what is an artificial pacemaker
3 points

Answer 21

1) used to control the heartbeat if the natural pacemaker cells don’t work properly
2) it’s a little device that’s implanted under the skin and has a wire going to the heart
3) it has an electric current to keep the heart beating regularly

Question 22

what are the three different types of blood vessels and what do they do
3 points

Answer 22

1) arteries - these carry the blood away from the heart
2) capillaries - these are involved in the exchanged of materials at the tissues
3) veins - these carry blood to the heart

Question 23

describe the characteristics of arteries
3 points

Answer 23

1) the heart pumps blood out at high pressure so the artery walls are strong and elastic
2) the walls are thick compared to the size of the hole down the middle (the lumen)
3) they contain thick layers of muscle to make them strong ans elastic fibres to allow them to to stretch and spring back

Question 24

describe the characteristics of capillaries
6 points

Answer 24

1) arteries branch into capillaries
2) they are really tiny, too small to see
3) they carry the blood really close to every cell in the body to exchange substances with them
4) they have permeable walls, so substances can diffuses in and out
5) they supply food and oxygen, and take away wastes like CO2
6) their walls are usually only one cell thick. this increases the rate of diffusion

Question 25

describe the characteristics of veins
4 points

Answer 25

1) capillaries eventually join up to form veins
2) the blood is at a lower pressure in the veins so the walls don’t need to be as thick as artery walls
3) they have a bigger lumen than arteries to help the blood flow despite the lower pressure
4) they also have valves to help keep the blood flowing in the right direction

Question 26

what is the job of red blood cells

Answer 26

they carry oxygen from the lungs to all the cells in the body

Question 27

what is the shape of red blood cells and how does this help
2 points

Answer 27

1) biconcave disc shape
2) this gives it a large surface area for absorbing oxygen

Question 28

why don’t red blood cells have a nucleus

Answer 28

allows more room to carry oxygen

Question 29

what is the red pigment in red blood cells

Answer 29

haemoglobin

Question 30

in the lungs and body tissues what happens to haemoglobin
2 points

Answer 30

1) in the lungs, haemoglobin binds to oxygen to become oxyhaemoglobin
2) in body tissues the opposite happens. the oxyhaemoglobin splits up into haemoglobin and oxygen to release oxygen to the cells

Question 31

what do white blood cells do

Answer 31

they fight against infection
1) some can change shape to engulf unwelcome microorganisms in a process called phagocytosis
2) others produce antibodies to fight microorganisms, as well as antitoxins to neutralise any toxins produced by the microorganisms

Question 32

what do platelets do

Answer 32

they help blood to clot at a wound, to stop blood pouring out and to stop microorganisms getting in

Question 33

what are platelets

Answer 33

these are small fragments of cells, they have no nucleus

Question 34

what can a lack of platelets cause

Answer 34

excessive bleeding and bruising

Question 35

what is plasma

Answer 35

plasma is the liquid that carries everything in blood

Question 36

what does the plasma carry
7 points

Answer 36

1) red and white blood cells and platelets
2) nutrients like glucose and amino acids
3) carbon dioxide from organs to the lungs
4) urea from the liver to the kidneys
5) hormones
6) proteins
7) antibodies and antitoxins