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
Explain the roles of insulin, somatostatin and pancreatic polypeptide
Insulin
• Hormone that allows glucose can be taken up by cells
Somatostatin
• Inhibits insulin and glucose release
Pancreatic polypeptide
• Plays a role in appetite and ion transport within the intestine
Explain the role of glucagon, and define the following:
Glycogenolysis
Gluconeogenesis
- Glucagon works to increase blood sugar levels, opposing the work of insulin
- It stimulates the liver to convert its stores of glycogen back into glucose = glycogenolysis
- It stimulates the liver to take up amino acids from the blood and convert them into glucose = gluconeogenesis
- It stimulates lipolysis, the breakdown of stored triglycerides into free fatty acids and glycerol.It may travel to the liver and be converted to glucose
Understand the effects thiazides, epinephrine/ sympathetic activation and anti- covulsants have on insulin
They reduce the amount of insulin released
Describe the association between stress and hyperglycaemia
- Stress causes the release of adrenaline and cortisol/ growth hormone
- Adrenaline: promotes glycogenolysis which is the breakdown of glycogen into glucose = increase of blood glucose
- Cortisol/ growth hormone: makes fat and muscles cells resistant to the effect of insulin and enhances the production of glucose in the liver
List the oral manifestations of diabetes
- Narrowing of the blood vessels = reduce blood supply to the gums
- Increased the risk of infection
- High chances of periodontal disease
- Low saliva
- Dry mouth -> increase plaque and tartar
- Caries and periodontal disease
- An increase of sugars in the gingival fluid = caries
- Impaired immune system disease, fungal infection etc
- Delayed soft tissue healing – impairments in growth factor expression, impair angiogenesis and matrix formation, poor collagen formation, prone to infection
- Ketoacidosis: halitosis
- Peripheral neuropathy oral paraesthesia (burning mouth syndrome) and altered taste sensations
List complications that can arise due to:
Type I diabetes
Type II diabetes
Type I diabetes
• Diabetic ketoacidosis
Type II diabetes
• Hyperosmolar coma
• Macrovascular and microvascular changes
Describe diabetic ketoacidosis
• An extreme metabolic state where blood sugar is very high and acidic substance called ketones build up in the body
Describe hyperosmolar coma
Characterised by high blood and dehydration
Describe the macrovascular and microvascular changes associated with type II diabetes
Macrovascular:
• Heart disease
• Stroke
Microvascular :
• Nephropathy
• Retinopathy
• Neuropathy, foot ulcers
List the effects of insulin on the:
Liver
Adipose tissue
Muscles
Liver
• Glycogen synthesis
• Increased protein synthesis
• Increased lipid synthesis
Adipose tissue
• When the liver is has taken up its capacity of glycogen, insulin signals fat cells to take up glucose to be stored as triglycerides.
• Decreased lipolysis
Muscles • Increased glucose entry • Increased glycogen synthesis • Increased amino acid uptake • Increased protein synthesis in ribosomes
