Vitamin D is soluble in fat, but insoluble in water. It is present in the fat component of foods that eat. Suggest into which part of the villi is absorbed. Explain your suggestion. Enable Ginger Cannot connect to Ginger Check your internet connection or reload the browser Disable in this text field Rephrase Rephrase current sentence Edit in Ginger ×

The digested nutrients pass through the blood vessels in the bowel wall through a diffusion process. The inner wall, or mucous membrane, of the small intestine is covered with a simple columnar epithelial tissue. Structurally, the mucosa is covered with wrinkles or folds called plicae circulares. From the plicae circulares project microscopic finger-like pieces of tissue called villi (Latin for shaggy hair). Individual epithelial cells also have finger-like projections called micro villi. The function of the plicae circulares, the villi, and the micro villi is to increase the amount of surface area available for the absorption of nutrients.

E M B I B E

Biology for Cambridge IGCSE Workbook 4 th Edition Digital Access>Chapter 7 - Human Nutrition>Exercise 7.4>Q 11

MEDIUM

Upper Secondary-IGCSE

IMPORTANT

Earn 100

In an investigation into the absorption of vitamin D from the alimentary canal, a volunteer ate a measured quantity of vitamin D on a piece of roast. Blood samples were then taken from him at intervals over a period of 72 hours, and the concentration of vitamin D in each blood sample was measured.

The results are shown in the graph in figure 7.2.

Describe the changes in the concentration of vitamin D in the blood over the 72-hour period.

Important Questions on Human Nutrition

MEDIUM

Upper Secondary-IGCSE

IMPORTANT

Biology for Cambridge IGCSE Workbook 4 th Edition Digital Access>Chapter 7 - Human Nutrition>Exercise 7.4>Q 12

Calculate the percentage change in vitamin D concentration between 12 hours and 48 hours. Show your working. Give your answer to the nearest whole number.