Blood and the Circulation

Question 1

what three components are in plasma

Answer 1

red blood cells

white blood cells

platelets

Question 2

what does the plasma do

Answer 2

plasma transport various chemical substances around the body, such as the products of digestion:

hormones

antibodies

urea and carbon dioxide

Question 3

what do red blood cells do and contain

Answer 3

red blood cells contain haemoglobin, which binds to oxygen to transport it from the lungs to the tissues and cells, which is needed for respiration.

Question 4

characteristics of red blood cells

Answer 4

does not contain a nucleus so there is more room for hemoglobin

are very small so they can fit through tiny capillaries

shaped like biconcave discs, giving them a large surface area that oxygen can quickly diffuse across.

Question 5

characteristics of white blood cells

Answer 5

help to protect the body against infection

can change shape, so they can squeeze out of the blood vessels into the tissue or surround and engulf microorganisms

platelets are fragments of cells, which collect at wounds and triggers blood clotting

Question 6

how does the heart pump blood

Answer 6

blood enters the heart through the atria

there atria contract and force blood into the ventricles

the ventricles then contract and force blood out of the heart

valves make sure the blood flows in the correct direction

the natural resting heart rate is controlled by a group of cells located in the right atrium, which acts as a pacemaker

Question 7

what are the four chambers in the heart

Answer 7

there are four chambers in the heart:
the left and right atria, which receive blood from vines

the left and right ventricles, which pump the blood out into the arteries

Question 8

what are artificial pacemakers

Answer 8

Artificial pacemakers are electrical devices used to correct irregularities in the heart rate

Question 9

gaseous exchange

Answer 9

the heart sends blood to the lungs via the pulmonary artery

air obtained by breathing reaches the lungs through the trachea, which has rings of cartilage to prevent it from collapsing

the trachea divides into two tubes - the bronchi

the bronchi divides into bronchioles

the bronchioles divide until they end in tiny air sacs called alveoli.

the blood is taken back to the heart through the pulmonary vein

Question 10

characteristics of alveoli

Answer 10

they have a large moist surface area.

they have a very rich blood supply

they are very close to the blood capillaries, so the distance for gases to diffuse is small