Year 8 Revision questions on Respiratory, Circulatory and Excretory Systems 2014

Name: Mr. Hung 2014 ANSWERS
Circulatory System

  1. What are the 2 main function of the circulatory system?
    To transport oxygen from lungs to all cells for respiration.
    To transport metabolic wastesincluding urea and Carbon dioxide (a gas) for excretion.
  2. The 3 main parts of the circulatory system are Heart, Blood & Blood vessels.
  3. Blood consists of 55% of plasma( the liquid part) and 45% of blood cells, including the
    Red blood cells, White blood cells & platelets.
  4. The red blood cells consist of a red pigment called Haemoglobin( a protein with iron), which is responsible to carry Oxygen( a gas).
  5. White blood cells are colourless and can change shapes, they are responsible to protect us from infection, by killing germs.
  6. Blood platelets are responsible for blood clotting when the skin is wounded.
  7. The following are the chemicals found in the blood:
  8. nutrients: glucose, amino acids, vitamins, minerals
  9. useful chemicals: hormones, proteins, antibodies, oxygen, heat
  10. wastes: carbon dioxide, urea, ammonia, heat
  11. All of these chemicals are carried by Plasma except oxygen, which is carried by
    Red blood cells.
  12. Glucose and oxygen are delivered by blood vessels to the living cells where respiration takes place. What is the main product of the reaction and the 2 metabolic wastes?

Main productEnergy Metabolic wastes Water + Carbon dioxide

*****************************************************************************

  1. How would you describe our heart?
    It is a muscular organ with 4 chambers. There are 2 atria and 2 ventricles.
    The left side and right side of the heart are separated by septum.
  2. There are 3 main types of blood vessels: arteries, veins and blood capillaries
  1. Both veins and arteries are larger blood vessels for delivery of blood to different organs.
    Artery is a blood vessel always carries blood AWAY from the heart.
    Vein is a blood vessel always carries blood TOWARD the heart.
  2. Capillaries are very fine blood vessels, which are only one-cellthick. This allows the exchange of substances between the cells and blood.
    Glucose and Oxygen enter the cells from the capillaries whereas wastes such
    as Urea and Carbon dioxide leave the cell and enter the capillaries.

  1. Valves can be found in the heart as well as all theveins. Arteries are normally under high blood pressure and do not require valves. The main function of the valves is
    to prevent the blood from backflow or allow blood to flow in one direction.
  2. Label all these parts in the diagram:
    Left ventricleRight ventricleLeft auricleRight auricle
    Pulmonary arteryPulmonary veinVena cavaAorta

Valveseptum

  1. Blood full of oxygen is known as oxygenated blood (left side of the heart). What do you think about the colour of oxygenated blood?
    Bright Red
    Deoxygenated blood is found in Rightside of the heart and carries littleoxygen and is dull or dark red in colour.
  2. Draw arrows to show the blood flow throughout the heart. Using red pen for oxygenated blood and blue pen for deoxygenated blood.
  3. There are 2 main circulations in the body:
    Pulmonary (lung) circulation in which blood circulates between the heart and the lung.
    Systemic (body) circulation in which blood circulates between the heart and the Body.

Respiratory System

  1. The main purpose of Respiratory system is for breathing –Breathingis taken in Oxygenand Carbon dioxide is given out.
  2. The Life Process so called “RESPIRATION” is, in fact, not the same as “BREATHING”.
    Respiration is the process in which Glucose is broken down by Oxygen to release
    ENERGY inside all living cells.
    Glucose + Oxygen ------> ENERGY + Carbon dioxide + Water
  3. Label the diagram of the Respiratory System:

  1. Special features of Respiration system:

a)C-ring cartilage found in trachea is important to keep it open at all times.

b)Cilia (tiny hairs) and mucus in nasalcavity and trachea sweep dust and germs upward to be swallowed or split out.

c)There are 600 millions alveoli in 2 lungs, equivalent to a 70 square m of a tennis court.

Gas / Air in the atmosphere / Breathed out air
Oxygen / 21% / 16%
Carbon dioxide / 0.03% / 4%
Nitrogen / 78% / 78%
Water vapour / Small amount / 1% (saturated)
  1. Composition of atmospheric air and breathed out air:

a)Which gas consists of about ¾ of the air? Nitrogen

b)Which gas is used up by the body? How many percentage is used up? Oxygen 5%

c)What percentage of carbon dioxide is in the breathed out air? 4%

d)Which gas is not been used by our body at all? Nitrogen

  1. Name all the words for:
    Breathing in air= Inspiration, Inhalation
    Breathing out air = Expiration, Exhalation
  2. Arrange the following steps in order during Inhalation:
  1. This reduce the pressure inside the thorax
  2. The intercostal muscles in the ribs also contract, making the ribcage move upward and outward.
  3. Air moves through the air way of the respiratory system and
    eventually reaches the alveoli, filling Lungs with air
  4. The contraction of both the diaphragm and intercostal muscles increase the volume of the thorax (chest cavity)
  5. Air is rushed in from a higher air pressure to a lower one in the thorax (chest cavity).
  6. This inflates the lungs.
  7. Diaphragm is contracted and change the shape from Dome-shaped to flattened shape.
    G  B  D  A E  C F
  1. What happens at the Alveoli?
    Gas exchanges take place in which Oxygen diffuses from alveoli to blood capillaries and
    Carbon dioxide diffuses from blood capillaries to alveoli.

Excretory System

  1. Excretion is the removal of metabolicwastesfrom the body.
  2. There are 3 main parts involved in Excretion:

a)The SKIN is used to remove sweat, salt, urea and heat from the body surface.

b)The Lungs are used to remove carbon dioxide and water vapour.

c)TheKIDNEYS being part of the Urinary system are responsible to remove metabolic wastes including urea, ammonia, excess salts and water.

  1. Blood vessels of the Kidneys:

a)The Aorta has a branch given to the kidney called Renal artery.

b)This blood is filtered by the kidney and forms Urine- about 2L per day.

c)160 L of blood is filtered per day from 5 L of blood in the body,

d)The rest of the blood will be collected to the renal vein (clean blood) and then go to Vena Cava.

  1. Urine is actually formed from blood: It is different from blood in chemical composition:

Blood / Urine
Blood cells / Red blood cells, white blood cells and platelets / No blood cells at all
Colour / Red because of Red blood cells or Haemoglobin / Not red, slightly yellow like the plasma of blood
Protein / Lots of different proteins / No proteins
Urea (metabolic waste) / Relatively small amount / More concentrated
  1. Each kidney consists of microscopic units called nephrons; about 1 millions each.
  2. The kidney actually form urine every second, it is transported by theureterand is stored in the urinary bladderto be emptied when it is full.
  3. The Urethra is a narrow tube from the bladder for the urine to pass out. It is a lot longer in male, found in the middle of the penis.