Topic D Human Physiology

Question 1

Define

Nurtient

Answer 1

Chemical substances in our bodies that come from food.

Question 2

Define

Essential Nurtrients

Answer 2

They are chemical substance needed in our body whose only source came from food.

Question 3

Define and provide two way its function can be replaced

Non-essential nurtrient

Answer 3

Chemical substance needed in our body which can be created from other existing substances or whose role can be performed by another substance.

Question 4

Provide an example of a non-essential nurtrients and how it is replaced.

Answer 4

Glucose’s role as energy souce can be replaced by lipids.

Question 5

Define

Conditionally essentials nurtrients

Answer 5

Chemical substance needed in our bodies at only specific developemental stages.

Question 6

Provide an example of a conditionally essentials nurtrients

Answer 6

Vitamin K produced by intestinal bacteria can’t be produced in newborns.

Question 7

Which gene’s mutation causes inability to produce ascorbic acid in human.

Answer 7

GLO

Question 8

Which enzyme’s absence is responsible for the inability to produce ascorbic acid in human?

Answer 8

L-gulono lactose oxidase needed for the last step of ascorbic acid production.

Question 9

Which vertabrates is unable to produce ascorbic acids?

Answer 9

Primates

Question 10

What diseases occured in the absence of ascorbic acid?

Answer 10

Scurvy

Question 11

State the two essentials fatty acids.

Answer 11

alpha-linoloeic acid (omega 3)
linoloeic acid (omega 6)

Question 12

State the role of the two essentials fatty acids.

Answer 12

Biosynthesis of compounds needed in brain and eye developement.

Question 13

State and explain the two conditionally essentials amino acid.

Answer 13

theoronine (producable from phenylalenine)
arginine (not produceable in infants)

Question 14

Explain edema. [3 marks]

Answer 14

1. Diet lacking 1 amino acids or all in general cause protein deficit malnurtrition.
2. This reduced blood plasma protein which causes fluid retention.
3. The fluid retention causes bloating called edema.

Question 15

Explain Iodine deficit disorder and how to prevent it. [4 marks]

Answer 15

1. Low Iodine in diet prevents thyroxin production in thryroid gland.
2. This causes Iodine deficit disorder.
3. This causes permanent mental and brain damage.
4. This can be prevented by adding iodine into salt.

Question 16

Define

vitamins

Answer 16

Chemical compounds needed in small amount but unsynthesized able in our body.

Question 17

Explain Phenylketonuria in term of its cause and effect. [3]

Answer 17

1. Presence of 2 reccesive alleles causes phenylalenine hydroxidase to not be produced.
2. The absence of the enxymes above prevents phenylalanine to be converted into tyrosine.
3. The increase [phenylalanine] causes reduced cranial growth, seizures, mental retardation and hyperactivity.

Question 18

Provide how phenylketonuria can be detected and prevented. [2 marks]

Answer 18

1. Phenylketonuria can be detected in new born, as its phenylalanine only started to raise without mother’s metabolism.
2. Patients should eat non-phenylalanine food and taking tyrosine supplements.

Question 19

Outline how vitamin D are supplied in our body. [2 mark]

Answer 19

1. Vitamin D can be synthesized by teenagers and adult skin under 290-310 nm U.V rays.
2. Vitamin D can be supplied to children, elders and pregnant women by diets containing vitamin D (oily fishes like herring, sardines, et.c).

Question 20

Explain the impact of vitamin D’s deficit. [2 marks]

Answer 20

1. Vitamin D deficit has similar symptoms to Calcium deficit, as it is needed for Ca to be absorbed by the intestine.
2. The lack of Ca means bone is weaker and curved, causing rickets.

Question 21

Provide reasons why animals don’t have their digestive system active constantly. [2 marks]

Answer 21

To conserve energy between meals and for fight/flight response.

Question 22

Outline the nervous mechanism that regulates digestive secretions? [4 marks]

Answer 22

1. Upon detecting food, the brain’s medulla sends a signal down the vagus nerve.
2. The signal reaches the stomach wall’s gland cell and causes gastric juice to be secreted.
3. Upon detecting peptide with chemoreceptors and stomach distenstion, the brain’s medulla sends a signal down the vagus nerve.
4. The signal causes gastrin to be secreted by G-cells in the endocrine system.

Question 23

Outline the hormone mechanism that regulates digestive secretions? [5 marks]

Answer 23

1. Gastrin secreted by G-cells causes acids and pepsinogin to be secreted by Parietal cell and chief cell respectively.
2. This lowers the pH.
3. When the acidity is too high, secretin and somatostatin is secreted by D-cells.
4. This inhibits gastrin production.
5. This negative feedback loop regulates acidity.

Question 24

Where and which cells secretes gastrin?

Answer 24

Endocrine G-cells in the doedenum and stomach.

Question 25

Name a stomach endocrine cell.

Answer 25

G-cells

Question 26

Name two types of stomach endocrine cell and what they secrete.

Answer 26

1. Parietal cell secretes acid. 2. Chief cell secretes pepsinogen.

Question 27

Describe the structure of exocrince gland cells and how it relates to its functions. [4 marks]

Answer 27

1. Plenty of mitochorndira is needed for ATp production for protein synthesis. 2. Plenty of endoplasmic reticulum for enzymes synthesis. 3. Plenty of secretory vesicles containing enzymes for secretion. 4. Tight junctions between the cells to keep toghether.

Question 28

Describe where exocrine cell acinus is found and where fluid is secreted into. [3 marks]

Answer 28

1. Acinus are found around ductules. 2. They secrete into epithelial membranes. 3. These membranes includes the skin for sebacous gland and alimentary canal's lumen.

Question 29

State the three locations where exocrine cell secretes into the alimentary channels, the name of the fluids and their content. [3 marks]

Answer 29

1. Salivary gland secretes saliva containing amylase. 2. Stomach gland cells secretes gastric juice containing HCl and pepsin. 3. Pancreatic exocrine cell secretes pancreatic juice, containing HCO2-2, amylase, lipase, peptase, trypsinogen.

Question 30

State some adaptations of the villus epithelial cells, and explain its function. [4 marks]

Answer 30

1. Tight junctions between epithelial cells allows materials to pass into the blood stream after entering them. 2. Brush borders made of microvilli increase surface area for absorption. 3. High amounts of mitochondria and pinocytic vesicles porduces ATP and vesicles needed for active transport and endocytosis. 4. Proteins on both the apical and basal surface membrane allows transportation of many materials.

Question 31

Who are involved in discovery of the chemical digestion of the stomach?

Answer 31

William Beaumont (a surgeon) discovered it after analyzing a stomach gun wound on Alexis St. Martin.

Question 32

Which cell secrete acid in the stomach during digestions.

Answer 32

Parietal Cells.

Question 33

Describe the roles of acid during digestion. [3 marks]

Answer 33

1. Acid disrupt extracellular matrix that hold cells together in tissues. 2. Acid denatures protein, exposing the polypeptides to pepsin to be digested. 3. Acid activates pepsin from pepsinogen.

Question 34

State the name of the bacteria that causes stomach ulcer.

Answer 34

Helicobacter Pylori

Question 35

Outline what stomach ulcers is and how they form. [2 marks]

Answer 35

1. Ulcers are open sores in the stomach. 2. It us caused by the partial digestion of the stomach lining by pepsin and HCl.

Question 36

State the name of the substance that reduces the production of stomach acids. [1 marks]

Answer 36

Protein Pumps Inhibitors (PPIs)

Question 37

State the two conditions that might requires the reduction of stomach acid production. [2 marks]

Answer 37

1. Ulcers caused by acid digestions. 2. Acid Reflux where acid got into the esophagus if the sphlincter at the top of the stomach.

Question 38

Explain how PPIs reduced acid production in the stomach temporarily. [3 marks]

Answer 38

1. PPIs are inactive until it reaches the parietal cell, where the acid around it cause PPI to become active. 2. PPIs bound irreversible to the protein pump and prevent it from pumping out 2H⁺ and taking in 2K⁺. 3. The pH lowers until the protein pump is recycled and the acid conditions are restablished.

Question 40

Define egestions. [1 marks]

Answer 40

The removal of excretory products as feces.

Question 41

Describe the substances that is excreted during egestions. []

Answer 41

1. Undigested materials like cellulose, lignin. 2. Excretory products from our body (not just digestion) like bilirubin from red blood cell's break down. 3. Digestive secretions from the mouth, stomach and small intestine.

Question 42

Provide some examples of dietary fibres and where to find them.

Answer 42

Cellulose, lignin and pectin found in whole grain bread and vegetables.

Question 43

Provide some benefits of eating dietary fibres. [3 marks]

Answer 43

1. Increase fecal movement as the fibre liquidfy it by pulling in more water. 2. Decrease the risk of obesity and Type II diabetes by adding bulks to diets, reduce apetite, and slows down absorption of sugars. 3. Lower the risk of hemorrhoids and appendicitis.

Question 44

Name the bacteria that causes chlorea.

Answer 44

Vibio Cholorea

Question 45

Outline how chlorea causes dehydrations.

Answer 45

1. Vibio chlorea secretes substance that binds to receptor on the intestinal cell, and is endocytosis. 2. This causes a reaction cascade that causes Cl^- and HCO^- to be effluxed en masses. 3. This causes water to osmosis out and causes dehydration.