User interface language: English | Español

Date November 2019 Marks available 2 Reference code 19N.3.SL.TZ0.17
Level Standard level Paper Paper 3 Time zone TZ0 / no time zone
Command term Outline Question number 17 Adapted from N/A

Question

The stomach secretes hydrochloric acid into its lumen.

The electron micrograph below shows part of an epithelial cell from the digestive system.

[Source: Louisa Howard, Katherine Connollly – Dartmouth Electron Microscope Facility]

State one mechanism that controls gastric secretion.

[1]
a.i.

State the type of gland that secretes juices into the digestive system.

[1]
a.ii.

State where this type of cell can be found in the digestive system. 

[1]
b.i.

Outline two adaptations of this cell to its function that are visible in this electron micrograph.

[2]
b.ii.

Markscheme

sight/smell of food
OR
negative/positive feedback
OR
nervous control/vagus/parasympathetic nerve stimulation
OR
hormonal control / gastrin / secretin / somatostatin ✔

a.i.

exocrine ✔

Do not accept name of specific digestive gland.

a.ii.

small intestine/duodenum/ileum/jejunum ✔ 

Villi alone not acceptable. Accept intestinal villi.

b.i.

a. microvilli increase the surface area for absorption ✔ Each adaptation needs function stated. Do not accept villi, microvilli is required.

b. many mitochondria produce ATP/energy «for active transport» ✔

c. vesicles resulting from endocytosis ✔

b.ii.

Examiners report

[N/A]
a.i.
[N/A]
a.ii.
[N/A]
b.i.
[N/A]
b.ii.

Syllabus sections

Option D: Human physiology » Option D: Human physiology (Core topics) » D.2 Digestion
Show 48 related questions
Option D: Human physiology » Option D: Human physiology (Core topics)
Option D: Human physiology

View options