The lumen of the trachea is lined by pseudostratified columnar epithelium. Note that all the surface cells have cilia at their free (apical) surface. (What function do these cilia serve in the trachea?) Mucus-secreting unicellular gland cells (goblet cells) are interspersed among the ciliated cells.
Donât think you need to be able to do the modified version perfectly before you try theseâyou just need to feel brave enough to go upside down. To complete a handstand push up: 1  Face a wall in a standing position.  Kick your feet up so youâre in a handstand position against a wall.
From the push up position, drop down to your knees so that you're on all fours. Lift the right leg out to the side, keeping it straight at a 90-degree angle. Point your toe and lift your right leg up and down for one minute. Lightly touch the floor with your toes. Repeat on the left side.