The lumen of which of the following systems is part of the internal environment?
A)cardiovascular system
B)urinary system
C)gastrointestinal system
D)gastrointestinal and urinary systems
E)respiratory system

Question

Quizplus · Accepted Answer

The cardiovascular system's lumen is part of the internal environment as it is enclosed within the body and directly interacts with the body's cells and tissues, unlike the gastrointestinal and respiratory systems which are exposed to the external environment.

The Lumen of Which of the Following Systems Is Part