Question
Describe the composition and functions of blood

Answer

Blood is a fluid connective tissue. There are three types of blood corpuscles:
  1. RBC's or Erythrocytes: These are bi-concave, denucleated, disc like. They contain red coloured respiratory pigment called haemoglobin that helps in the transportation of oxygen.
  2. WBC's or leucocytes: These are irregular, amoeboid, phagocytic cells with one to many lobed nucleus. These cells protect the body against the diseases by producing antibodies.
  3. Blood platelets or thrombocytes: These are spindle shaped cells which help in the clotting of blood.
Functions of blood:
  1. It transports nutrients, hormones and vitamins to the tissues and transports excretory products from the tissues to the liver and kidney.
  2. The RBCs carry oxygen to the tissues for the oxidation of food stuff.
  3. WBCs fight disease by engulfing and destroying foreign bodies.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

State the law of constant proportions. Give one example to illustrate this law.
Differentiate between pathogens and pests. How does an insect-pest attack the plants?

Explain the mechanism of compost formation.

Three different vibrating objects produce three types of sounds X, Y and Z. Sounds X and Y cannot be heard by a man having normal range of hearing but sound Z can be heard easily. The sound X is used in hospitals to break kidney stones of a patient into fine grains whioch then get flushed out with urine. The sound Y is similar to that which is produced during an earthquake before the main shock wave is generated.
  1. What type of sounds are (i) X, (ii) Y, and (iii) Z?
  2. Name one device which can produce sound like X.
  3. Name one device in a science laboratory which can produce sound like Y.
  4. Name one device in our homes which can produce sound like Z.
  5. What is the frequency range of sounds like Z?

Write a note on cattle feed.

Draw a neat labelled diagram of an animal cell.
A train travels the first 15km at a uniform speed of 30 km/h; the next 75km at a uniform speed of 50km/h; and the last 10km at a uniform speed of 20km/h.
Calculate the average speed for the entire train journey.
Describe the structure and function of different types of epithelial tissues. Draw diagram of each type of epithelial tissue.
There is a water reservoir (river) near a village. Due to insufficient rain, farmers are worried about their crops. Suggest and explain the irrigation practice that can be adopted to supply water to the entire agricultural land in the village.
Discuss various methods for weed control.