Agni
Being one of the panchamahabhoota, agni (fire) has the characteristic that it cannot exist without a base. For example, coal, kerosene etc. are few substances in which agni exists. Like wise in the body it exists in pitta dosha.

Ahaar Pachan
The process of digestion (ahar pachan) is divided in three stages, which collectively is called awastha paka and can be divided in the following:
Amavstha (Madhuravastha) Paka ; Pachymanavastha (Amlavstha) Paka ; Pakavstha (Katuavstha) Paka

Dhatu Poshan
It refers to the nutrition of different dhatus in the body through digested food (pachit ahar rasa). Three different theories exist in ayurveda that explain the process of nutrition of dhatu from the digested food (ahar rasa), namely:
Kshir Dadhi Nyaya ; Kedar Kuliy Nyaya ; Khala Kapot Nyaya

Dosha Dhatu Mala
These are the main constituents of sharir, namely, dosha, dhatu and mala. It is the root cause of Utpati (origin), Sthiti (stability i.e. development growth) and Laya (destruction) of the body. When they are in Sama Sthiti (equilibrium) they maintain the body in healthy condition but as there is an imbalance or inappropriate proportion (Visam Sthiti) of these it leads to disease and death.

Oja
Oja is the essence of dhatus, which gives strength to the body, improves immunity power and takes care of well being of the body. It is present all through the body like ghee exists in the milk or honey exists in the flower.

Panchbhoutic Siddanth
To understand physiology, pathology and pharmacokinetics of ayurvedic therapeutics the concept of panchbhoutic siddanth is of vital importance. Phrithwi, Aapa, Teja, Vayu and Akasha are the five (Pancha) basic elements that are the constituents of all living matter. Together these five are called Panchamahabhoota.

Purusha
The "Soul" lives in the body so it is considered as purusha, as anyone who live in this home i.e. body is called purusha. In ayurveda the body has no meaning without purusha (soul). Two meanings of soul are to be considered the ayurvedic concept regarding the purusha: First meaning is considered for "Jeevetma" (soul) which is called as "shuddha purusha".