Hypoxia is a condition in which tissues of the body are deprived of an adequate oxygen supply. A study was carried out in rats to examine the effects of continuing hypoxia on the structure of the diaphragm, and to determine whether nitric oxide is implicated in adaptation of the diaphragm to hypoxia. The diaphragm helps to supply oxygen to tissues and organs in the body by ventilating the lungs.

A group of 36 adult male rats were kept for 6 weeks in low oxygen while 36 adult male rats were kept in normal oxygen levels.

The image shows part of a mammalian cell.

What is the specialized function of this mammalian cell?

The micrograph shows part of a cell.

Which principal function is this cell likely to have, as judged by its cell structure and organelles?

Bacteria from chicken feces can cause a loss of intestinal villi in small children who happen to eat dirt in rural villages. Which effect could be expected from such a loss of villi?

Substances can move into and out of cells through the cell membrane.

Humans ingest food which provides energy and nutrients to carry out life processes.

In which process is "surface area" of key importance for humans?

Breastfed infants with rickets sometimes have seizures due to low blood calcium levels. A study was carried out to investigate the relationship between maternal blood vitamin D levels and the incidence of these infant seizures.

Intestinal villi are highly specialized for the absorption of digested nutrients. The micrographs show some epithelial cells on the surface of the villi and a detail of two of these cells.

The diagram shows the emulsion and absorption of a fat globule in the gut.