Obesity and diabetes Flashcards
Explain how carbohydrates, proteins and triglycerides are absorbed.
- The intestines breakdown these three macromolecules into micronutrients; proteins become amino acids, triglycerides become glycerides and fatty acids and carbohydrates become glucose
- These nutrients are taken into liver by the portal vein
Explain the process of cellular respiration
Glycolysis
• Glucose is a 6 carbon molecule
• This is broken down into two 3 carbon molecules called pyruvate
• ATP is produced
Oxidation
• When oxygen is present, the two pyruvate molecules enter the mitochondria
• Each pyruvate molecule is converted into acetyl- CoA by NADH (oxidised)
• H electrons from each pyruvate are transferred to NAD, reducing it to NADH
• A carbon is lost, forming Co2
Krebs cycle
• Acetyl CoA bins with a 4 carbon molecule called oxaloacetate
• A series of enzymatic reactions take place
• Many NADH/ transport carriers are formed
Electron transport chain
• High energy electron carriers (NADH) from the previous stages bring their electrons to the transport chain
• The electron carriers bind to transport proteins, releasing their electrons into the mitochondrial intermembrane space
• These ions flow back into the mitochondria through a ATP synthase enzyme
• The energy yielded from the ions flowing into the enzyme enables ADP to be phosphorylated into ATP.
• 32 - 38 ATP are created
• This is done in the presence of oxygen
Explain how fats and proteins are able to participate in cellular respiration when glucose reserves are depleted
Fats as fuel:
• Triacylglycerol are stored in adipose cells
• Lipases break the glycerol head away from the fatty acids.
• Glycerol is converted to an intermediate in glycolysis called “PGAL”, and enters cellular respiration in the cytoplasm.
• The fatty acid tails are converted to Acetyl CoA and enter the Krebs cycle in the mitochondria
Proteins as fuel:
• Proteases break down proteins into amino acids
• Deaminases break the amino group from the amino acid, releasing ammonia
• The remaining amino acids molecules can be rearranged to become a pyruvate, acetyl CoA
Define Metabolic Syndrome
Isa clustering of at least three of the five following medical conditions: central (abdominal) obesity, hypertension, high blood glucose, high serum triglycerides and low serum HDLs
Explain the role of adipocytes in the development and pathophysiology of MetSy
Adipose tissue
• Composed of adipocytes, cells that store energy as fat
• Adipocytes are regarded as endocrine organs. They synthesise and release adipokines
Proinflammatory adipokines
• Some pro-inflammatory adipokines include leptin, resistin, TNF and IL- 6. These induce chronic inflammation, promote insulin resistance and thus contribute to metabolic dysfunction
Explain the role of the following in MetSy:
* Obesity and hypertension
• Excess food intake/ genetics/ being sedentary leads to adipogenesis = overweight
• Being overweight forces the heart to work faster which wears the endothelium of vessels quicker
• This leads to hypertension
With vessel damage, the SNS is activated causing vasoconstriction and sodium retention
Explain the role of the following in MetSy:
* Insulin resistance
- Being overweight leads to excess insulin production. Overtime, the body becomes desensitised to insulin
- This places stress on the pancreas causing damage
- When adipocytes develop insulin resistance, they can no longer take up glucose and free fatty acids
Explain the role of the following in MetSy:
* Hyperlipidaemia
• Excess circulating free fatty acids are redirected to the liver
• The liver also makes its owns lipids through lipogenesis
• This results in elevated triglyceride levels
= Cholesterol
List the health impacts of obesity
- Hypertension
- High LDL cholesterol, low HDL cholesterol
- Type 2 diabetes
- Coronary heart disease
- Stroke
- Gallbladder disease
- Osteoarthritis
- Sleep apnea and breathing problems
- Low quality of life
- Mental illness such as clinical depression and anxiety
- Body pain and difficulty with physical functioning
Diagnose MetSy using the most appropriate risk factor criteria
- Central obesity plus any two of the following four factors: high triglycerides, high blood sugar, hypertension and reduced HDL cholesterol
- Can use BMI or body fat distribution methods
What are the ranges of BMI?
BMI=Weight/Height
• Normal range 18.5 – 24.9
• Overweight 25 – 29.9
• Obese >30
List the limitations of BMI
- Doesn’t factor in body fat distribution
- Doesn’t consider ethnicity
- Cannot accurately provide an indication of intra- abdominal adiposity
- Does not differentiate between fat and lean body mass. For example, an athlete with a large amount of muscle mass could fall into the overweight category
- Age and gender: women tend to have more body fat than men, older people have more fat than children
Describe how body fat distribution is assessed
- It focuses on the amount of central fat
* It involves measuring waist circumference and hip circumference and assessing which ranges the individual falls into
List the functions of the exocrine and endocrine pancreas
- Exocrine pancreas: digestive enzymes released into the GIT
* Endocrine pancreas: releases hormones into the bloodstream
List the names of the following pancreatic islelts: • α – cell • β – cell • δ – cell • γ – cell
- α – cell: glucagon
- β – cell: insulin (most abundant)
- δ – cell: somatostatin
- γ – cell: pancreatic polypeptide
