Human digestive system and nutrition

Question 1

How is obesity defined, and what are some hypotheses proposed to explain current obesity rates?

Answer 1

Obesity is defined as dangerous disease characterized by an abnormal BMI. It increases risk for various life threatening diseases.
- More sedentary lifestyle
- Human predisposition to gain weight because of the way we evolved. Our bodies evolved to maintain fat cells during periods without food, making it difficult to lose weight once you gain it.
- Linked to HORMONES keeping body weight at its set point, which vary by person
- Poor food choices promote inflammation and disrupt gut brain access

Question 2

How does the body use the energy in food?

Answer 2

When we take in food, we digest it by breaking down the macromolecules into subunits that will provide building blocks for new molecules and new energy sources
- Macromolecules contain different amounts of stored energy, and calories represent the amount of energy needed to raise water temp
Nucleic acid, carbs, proteins, and fat

Question 3

How does aerobic respiration extract useful energy from food?

Answer 3

aerobic respiration extracts useful energy from food by breaking down molecules and using the energy released to power the creation of ATP molecules, which are the energy currency of cells. and produces carbon dioxide and water as waste products.

Question 4

Glucose

Answer 4

as autotrophs we make this ourselves, and use it either to make the cell work or store energy for later

Question 5

Glycogen

Answer 5

(short term energy storage) complex carb made up of a bunch of linked up glucose molecules in muscles and liver cells

Question 6

Triglyceride

Answer 6

(long term energy storage) lipid in fat cells, used for long term because fat is higher in calories and is therefore more efficient (smaller but holds more)
- We’d nearly double our size if we used glycogen for the long term!

Question 7

What is the anatomy of the digestive system?

Answer 7

We start by chewin the food to maximize surface area, and food then travels down the esophagus into the stomach. The stomach takes a “scorched earth approach” using gastric juice, hydrochloric acid, pepsin and water and mucus to break down the contents. The pepsin in the stomach breaks down proteins into amino acids, and chyme leaves the stomach. The food moves to the small intestine where villi absorb nutrients. Bile from the gallbladder breaks down fat molecules into fatty acids and monoglycerides. Then it moves to the large intestine, which uses cecum to get rid of water and bile salt, preparing it to be excreted. The appendix holds onto the good bacteria and it moves to the anal sphincters.

Question 8

How is food broken down and utilized as it moves through the digestive tract?

Answer 8

A. Fat broken down into fatty acids and glycerol
1. Body breaks down tryglycerides from lipids into these building blocks
2. Stored in adipose tissue to cushion your organs, form myelin and oild in the skin
B. Protein broken down into amino acids
1. In muscles and connective tissues, ion channels and pumps, and make up enzymes
2. 20 amino acids - DNA resembles acids through anabolic reactions
3. Essential Amino Acids: 9 that must be consumed (can’t be produced)
C. Carbs broken into glucose
1. Monosaccharides and polysaccharides
2. Glucose - “be all end all” mollecular fuel that cells need for ATP (drives anabolic reactions)

Question 9

How does bariatric surgery change the digestive tract and digestion, and what are some of the risks and benefits of bariatric surgery?

Answer 9

A. This surgery makes the volume of the stomach smaller by stapling part of it off. This makes it so that the stomach is filled faster. Hormones produced by the stomach signal a reduction in the amount of grelin produced. Leptin then decreases as well because there is less adipose tissue.
B. Benefits and dangers: weight loss and decrease in risk factors that contribute to heart disease (high blood pressure, diabeties), BUT complications can include nutrituional deficiencies, infection, bleeding, and GI distress.

Question 10

How is the weight setpoint regulated

Answer 10

A. Weight set point is the range of what we think we should weigh, controlled by the hypothalamus

ARC is the control center and contains 2 groups of neurons (an appetite stimulating one and an appetite suppressing one that respond to hunger or satiety)

Leptin (satiety hormone) increases when adapost tissue increases

Question 11

What are the implications of the hormonal regulation of appetite and metabolism on the treatment of obesity?

Answer 11

A. The hormonal regulation of appetite and metabolism has significant implications for the treatment of obesity. For example, medications that target these hormonal pathways, such as GLP-1 receptor agonists and leptin analogues, have been developed for the treatment of obesity and type 2 diabetes. These medications can help to reduce appetite, increase feelings of fullness, and improve glucose control.
B. Bariatric surgery, which modifies the digestive tract to reduce food intake and/or absorption, has also been shown to have significant effects on hormonal regulation. For example, gastric bypass surgery has been shown to increase levels of GLP-1 and reduce levels of ghrelin, which may contribute to the weight loss seen after the procedure.

Question 12

What are macronutrients

Answer 12

proteins, carbs, and fats

Question 13

what are micro nutrients

Answer 13

Vitamins and minerals

Question 14

Catabolic reaction

Answer 14

destroys the reactants reducing big complex substances to molecular rubble
(metabolism)

Question 15

Anabolic

Answer 15

reassembles that rubble into new/bigger products (metabolism)

Question 16

What types of vitamins are there

Answer 16

Vitamins are compounds that come in fat/water soluble forms

Question 17

What are the building blocks of the four different types of macromolecules

Answer 17

Carbs→ simple sugars
Proteins→ amino acids
Fats→ fatty acids and glycerol
Nucleic acids→ nucleotides

Question 18

What is diabeties and how does it relate to homeostasis

Question 19

What are the functions of the pancreus and how were they discovered

Answer 19

A. When you eat carbs, the pancreus senses the change in blood sugar and secretes insulin. When there is too little glucose in the blood, the pancreus releases glucagon

B. Pancreus regulates glucose in the blood

Question 20

What hormones are involved in the control of blood sugar levels

Answer 20

Insulin- Released by the pancreus and acts as a key to the fat cells to store the glucose. Lowers glucose

Glucagon - Released by the pancreus and works release glucose back into the blood to raise levels

Question 21

What is metabolic syndrome and how does it relate to the functions of the pancreas and of the cardiovascular system?

Answer 21

Is a cluster of conditions occurring together, that increase the risk for heart disease, T2D, and stroke. These include abdominal obesity, high blood pressure, high blood sugar, high blood insulin, abnormal cholesterol levels.

The pancreas secretes both insulin and glucagon, which regulate glucose in the blood.

When fatty foods and sugar enter the blood, they increase the blood glucose past normal levels.

The pancreas responds by releasing more and more insulin, leading to insulin resistance.

The fat cells don’t respond to the insulin as effectively, and therefore do not get the message to stop producing fat, leaving the glucose to circulate and the fat cells picked up by other muscles that dont need it.

insulin resistance is also associated with other components of metabolic syndrome, including high blood pressure and abnormal cholesterol levels. This is because insulin resistance can impair the normal function of the cells lining blood vessels, leading to inflammation, arterial stiffness, and atherosclerosis, which are all risk factors for cardiovascular disease.