biology yr9 easter assesment

Question 1

order that pumps blood aroumd body

Answer 1

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

Question 2

what 3 main things make up the circulatory system?

Answer 2

blood, blood vessels, heart.

Question 3

explain the double circulatory systems.

Answer 3

the first one: the rigtht ventricle pumps de oxygenated blood to lungs to get oxygenated and returns to heart.
second one : left ventricle pumps oxygenated blood around body and gives oxygen to body cells. returns to heart and lungs again.

Question 4

what branches off the arteries to make sure the heart gets all the oxygenated blood it needs?

Answer 4

coronary artery

Question 5

what are the 3 blood vessels

Answer 5

veins- in
capillaries- exchange and diffuse
arteries- away

Question 6

arteries

Answer 6

• elastic and very thick walls due to high pressure.
  big walls compared to lumen.

Question 7

veins

Answer 7

lower blood flow so smaller walls however has a large lumen to keep blood flow.
valves.

Question 8

capillaries

Answer 8

one cell thick for easy diffusion.
exchange oxygen, food and CO2
branch off arteries.
tiny lumen.
permeable walls.

Question 9

describe red blood cells

Answer 9

no nucleus, carry oxygen, bioconcave disk, large surface area to carry oxygen.
has a red pigment called haemoglobin which binds with oxygen in the lungs to create oxyhaemoglobin. opposite happens in body tissues and produces oxygen and haemoglobin.

Question 10

describe white blood cells

Answer 10

nucleus, eat microorganisms- phagocytosis. produce antitoxins to neutralise toxins from microorganisms. and antibodies to fight microorganisms.

Question 11

describe platelets

Answer 11

fragments of cell with no nucleus. helps clot blood to prevent blood loss and microorganisms comign in.

Question 12

describe plasma

Answer 12

carries just abt everything
urea, hormones, white and red blood cells, platelets, oxygen, co2, antibodies and antitoxins, glucose, amino acids.