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Questions are matching, or require short answers.

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Record your answers on the test.

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14. In the above drawing of the human heart, why are the walls of the ventricles thicker than the walls of the atria? (3 points)

> ventricles provide the major force for pushing blood out of heart into vascular system,

therefore have thicker muscle layer

15. What is the function of the "SA NODE" (Sinoatrial Node) in the heart? (3 points)

> pacemaker – sets the rhythm of heart contraction

16. Identify 3 substances (not cells) that are transported by the human circulatory system (3 points).

1. hormones

2. nutrients (amino acids, sugars, etc)

3. O2, CO2

> "blood" is as all inclusive, so blood is not an independent choice from O2, etc., however, I did count "water", "plasma", and any independent things that one could argue as being present in "blood".

17. Why is Oxygen required for life (what metabolic reaction requires oxygen)? (3 points)

> required in electron transport in mitochondria, electron acceptor, in production of ATP. Any answer that indicated some link to this was accepted. Some indication of energy and metabolism. But O2 has a very specific role.

18. How is CO₂ produced in the body? (3 points)

>byproduct of catabolism (glycosis, amino acid metabolism, etc). Actually produced during Kreb’s Cycle, inside mitochodria. Answers stating "part of glycolysis in side mitochondria" were accepted. Answers had to indicate metabolism in some way that was linked to this process.

19. What is Hemoglobin, and where is it located in the body? (3 points)

> Hemoglobin is a protein in your red blood cells. It binds and transports oxygen through your body. This question is one that I would place on a college entrance exam, and I would NOT let anyone into a life science related program who did not know what hemoglobin is. I was very shocked how few of you could answer this question.

20. Where does gas (O₂, CO₂) exchange occur in the body (2 places)? (3 points)

1. lungs (alveoli – capillaries)

2. tissues (capillary beds)

24. What is the mechanism / process that causes the LUNGS to INFLATE? (3 points)

> negative pressure is produce in the thoracic cavity by contraction of the diaphram

25. Where is the main site of nutrient uptake (absorption) in the human body (be specific)? (2 points)

> small intestine, all regions. If I had used the word "resorption", then kidneys might have been an acceptable answer (proximal tubule). But since the words were "nutrient" and "absorption", then the question referred unmistakenly to digestion. There is also some uptake elsewhere, but the main site is the small intestine.

26. What Enzyme(s) are present in saliva; what macromolecules do they degrade? (2 points)

> amylase, degrading starch (a macromolecule) to glucose (not a macromolecule). I will continue to include "macromolecule" questions and increasingly expect you to know what is ment by "macromolecule".

27. What is the function of HCl in digestion in the stomach? (2 points)

> Weakens ectracellular matrix in animal and plant tissue, making it easier to disperse or break up tissue. Also, pepsinogen is converted to pepsin in the acidic environment created by HCl. Because proteases can exist at neurtral pH, I do not consider protease activation the primary reason HCl is present. Rather, the weakening of the matrix that holds cells together is the primary reason. But either was accepted.

28. What Enzyme(s) are present in the stomach; what macromolecules do they degrade? (3 points)

> protease (pepsin), degrading proteins

29. What is the function / contribution of the PANCREAS in digestion? (3 points)

> secretes enzymes (proteases, etc. ) for digestion in the small intestine, secretes bicarbonate to neutralize the HCl coming in from the stomach. Either or both accepted. Pancrase functions not related to digestion were not accepted.

30. What is the function / contribution of the LIVER in digestion? (2 points)

> produces bile, for the break down of lipids. I accepted detoxification only if it was directly linked to the digestive process. Liver functions not related to digestion were not accepted.

The above diagram depicts the duodenum.

31. What is the function of the villi and microvilli of the small intestine? (3 points)

> maximize the absorptive surface area of the small intestine. I do not view these structures as essential for nutrient uptake, since this could occur with a smooth and non-folded epithelial surface. However, I did accept this function, at least for partial credit, depending on how it was stated.

32. Describe the process by which proteins are digested and the resulting material taken into the body (follow the protein from mouth to circulatory system (4 points).

mouth – mechanial breakdown of tissue (not of protein – your teath are not small enough)

stomach – protease degradation by pepsin

small intestine (duodenum) – further degradation by proteases (chymytrypsin, trypsin)

small intestine (throughout) – after fully being reduced to single or amino acids, the amino acids are transported across the epithelium, into the body, into the capillaries (blood)

> the answer did not require mention of the transport processes involved in getting amino acids across the epethilium, but full credit did require a focused explanation (non-carbohydrate) that involved proteolytic degradation in BOTH stomach and instestine. Fecal formation in the colon has not part in this answer.