Embedded Files
D2_Vocabulary.pdfD2_control-of-digestive-juices.pdfPractice Questions
Practice Questions
1. Exocrine glands secrete mucous and enzymes into the lumen of the gut, where else can you find exocrine glands?
2. Glands are essentially made from folding the epithelium to from a tube or sac. Their shape and size is about the same, but there are differences in the numbers of different organelles.
Which organelles a likely to be more prominent in gland cells compared to surface epithelial cells? (2)
3. Annotate this gland cell to explain the functions of each organelle in the process of mucus production (5)
Answers here.
Can you identify exocrine gland cells that secrete digestive juices or mucus and villus epithelium cells that absorb digested foods in the electron micrograph images below?
Worksheet here:
gut_epithelium_diags_ws.pdf
Watch the two short introductory videos - don't worry about the details (some are beyond IB)
solo_hexagons_gastric-secretions_sheets.pdf
SOLO Taxonomy (Structure of Observed Learning Outcomes) provides a simple model for three levels of understanding, surface, deep and conceptual. I find it is useful for helping students to develop a connected conceptual understanding of biological processes, and it's a quick visual aid to see how well students are doing in the lesson.
SOLO hexagons is an excellent chance for students to sort their ideas into a clear sequence which explains the concepts and provides some notes at the same time.
This short video Dr William Beaumont explains simply how William Beaumont discovered the acidity of the stomach and the speed of digestion.
Beaumont observed the activity of the stomach and its gastric secretions in the 1830's. How is this an example of serendipity?
This clip of public science shows how food looks just after it arrives in the stomach. Inside a stomach - using an endoscope
As well as the churning of the stomach what does the endoscope show?
This short explanation Armando Hasudungan stomach secretions gives details of the contents of the gastric juice and the cells which produce it. (Stop watching at 5:30 - the small intestines)
What are the correct functions of the Chief cells and the Parietal cells?
A short clip explaining where mucus is made and describing the way production of HCl is promoted. Focus on the How hydrochloric acid secretion is regulated
What is the important role of epithelial cells mentioned at the beginning?
D_gastric_juice_video.pdf
Curiosity and winning the nobel prize.
An excellent introduction to Marshll and Warren's work on H.pylori
Finding a cure for stomach ulcers - Interview with Professor Barry Marshall
h_pylori_histology_questions.pdfImagine that you are Dr Warren or Dr Marshall. analyse the biopsy images and the experiment data in Endoscope biopsy student worksheet​. Does the data support the claim that H. pylori causes ulcers?
Questions
Questions
What is the claim makes in the news headline?
What is the relationship between transit of food though the intestines and the speed of peristalsis?
Pizza, and chocolate are low in dietary fibre, what is the role of fibre, and what is its effect on the rate of transit of materials through the intestines?
Discuss whether the data in the velocity of bowel movements graph supports the hypothesis that eating chocolate pizza causes slow bowel movements and constipation?
Materials not absorbed by the intestines are egested as stools. Fibre is cellulose and difficult to digest. How could this explain why a vegetarian diet might have a larger mass of egested stools than other diets.
This Hollywood news story shows a new type of pizza which could cause particularly bad constipation.
peptic_ulcer.pdf
Gastric secretions animation here.
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