SB 4.28.4
tayopabhujyamanam vai
yavanah sarvato-disam
dvarbhih pravisya subhrsam
prardayan sakalam purim
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
When Kalakanya, daughter of Time, attacked the body, the dangerous soldiers of the King of the Yavanas entered the city through different gates. They then began to give severe trouble to all the citizens.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The body has nine gates: the two eyes, two nostrils, two ears, mouth, rectum and genitals. When one is harassed by the invalidity of old age, various diseases manifest at the gates of the body. For example, the eyes become so dim that one requires spectacles, and the ears become too weak to hear directly, and therefore one requires hearing aids. The nostrils are blocked by mucus, and one has to always sniff a medicinal bottle containing ammonia. Similarly, the mouth, too weak to chew, requires false teeth. The rectum also gives one trouble, and the evacuation process becomes difficult. Sometimes one has to take enemas and sometimes use a surgical nozzle to accelerate the passing of urine. In this way the city of Purañjana was attacked at various gates by the soldiers. Thus in old age all the gates of the body are blocked by so many diseases, and one has to take help from so many medicines and surgical appliances.