In this study, 120 tenth-grade students from 8 schools were examined to determine the extent of their ability to perceive the human body as a system after completing the first stage in their biology curriculum--"The human body, emphasizing homeostasis". The students' systems thinking was analyzed according to the STH thinking model, which roughly divides it into three main levels that are arranged "pyramid" style, in an ascending order of difficulty: 1. Analysis of system components--the ability to identify the components and processes existing in the human body system; 2. Synthesis of system components--ability to identify dynamic relations within the system; 3. Implementation--ability to generalize and identify patterns in the system, and to identify its hidden dimensions. The students in this study proved largely incapable of achieving systems thinking beyond the primary STH level of identifying components. An overwhelming majority if their responses corresponded to this level of the STH model, further indicating a pronounced favoring of structure over process, and of larger, macro elements over microscopic ones.