Author Question: Explain the function of the lacrimal sac. What will be an ideal ... (Read 27 times)

OSWALD · **on:** Jun 27, 2018

Explain the function of the lacrimal sac.

What will be an ideal response?

Question 2

Describe the layers of pleura and how they prevent friction caused by breathing.

What will be an ideal response?

dpost18 · **Reply #1 on:** Jun 27, 2018

Answer to Question 1

The enlargement of the upper portion of the lacrimal duct is known as the lacrimal sac. Tears secreted by the lacrimal glands are pulled into this sac and subsequently forced into the nasolacrimal duct by the blinking action of the eyelids. The sac is dilated and pulls in fluid as the muscles associated with blinking close the lids. The sac constricts, forcing the fluid down the nasolacrimal duct as the lids are opened.

Answer to Question 2

The visceral pleura is the membrane that covers the outside of the lungs. The parietal pleura is the membrane that lines the pleural or lung cavities. Between these two pleura is a small space which is filled with a serous fluid to prevent friction when the lungs expand and deflate.