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How to draw Skull diagram - CBSE, NCERT

The skull is composed of two sets of bones cranial and facial. Cranial bones are 8 in number, facial bones are 14. So, skull is made of total 22 bones. The cranial bones form brain box called Cranium which accommodates the brain. The facial bones give shape to the face. Now, lets see how we can draw a Human skull in simple easy steps.

1. Draw a arbitrary rectangular shape as shown.
2. Draw lower Jaw shape as shown.
3. Merge the two shapes as shown.
4. Draw Now, the shape of fore head, nose,mouth and chin as shown.
5.Erase previous stray lines and darken up.
6. Define the Mandible , Lower Jaw and Upper Jaw as shown.
7. Fill the teeth in the mouth as shown.
8. Draw Eye socket, Ear hole, Nasal hole on skull as shown in the figure.
9. Now carefully mark the different bones on skull.
First draw a round around ear hole. Next divide the space on skull in to three partitions. Mark the Zygomatic bone shape around eye socket.

Next, draw Nasal bone  on Nose. Next draw Lacrimal and Ethmoid bones in the eye socket as shown.

If you do little practice you can map the bone locations perfectly.
10. Now along the faint lines draw zig zag pattern to represent the fissures.
11. We have completed the details of skull. Now let's draw the outer skin on the skull.

Draw another line all along the outer boarder or the skull represent the skin on head and face.

Draw the Hyoid bone in the Neck and label the diagram neatly as shown. I assure you'll get full marks

How to draw sperm cell

The sperms are minute,microscopic and motile reproductive cells. They have an oval head piece, a neck, a middle piece and a long tail. Head piece consists of a large haploid nucleus. A sac like structure Acrosome is present in head piece which helps in fertilization. Middle piece has several mitochondria, which produce energy required for the movements of tail. Sperms live for a period of 24 to 72 hrs in the female reproductive system and afterwards they die and degenerate. Now lets draw a typical sperm cell.

 Draw a oval shape and make a wavy line as shown.
Make Neck and middle piece and tail along the line.

Draw several mitochondria inside middle piece as shown.

 Now neatly label the parts as shown above.