Class 20

Question 1

What is Metabolism?

Answer 1

The highly regulated processes through which nutrients are broken down, transformed, & otherwise converted into cellular energy to sustain processes of life & health.

Question 2

The Body’s Energy Systems (How is energy derived & why is it important?)

Answer 2

Body needs consistent, reliable, 24/7 supply of energy for all its physical, mental & emotional activities. Energy is derived from m food we eat. If not, body utilizes stored energy from previously ingested food, or as last resort, breaks down its own tissues for fuel.

Question 3

What is the function of the Digestive System?

Answer 3

Breaks down food into usable energy units:

● Proteins into amino acids, which are key component of enzymes, essential tissue building blocks, & important in transport of nutrients, hormones, etc.
● Carbohydrates (starches) into glucose, which is body’s primary fuel (easiest to use to create ATP, which is essential cellular energy source)
● Oils/fats into fatty acids, can be used as alternative energy sources if body is low on glucose, or converted into adipose, body’s long-term energy storage form; fatty acids are also important for building cell membranes & organelles as well as molecules such as hormones, ketone bodies & triglycerides

Question 4

What are triglycerides?

Answer 4

Major form of fat storage in body; built from fats and carbohydrates. Food calories that are not used immediately by body tissues are converted to triglycerides & stored in fat (adipose) cells. Hormones regulate triglyceride release from adipose tissue to help meet body’s needs for energy. Hypertriglyceridemia (excess volume of triglycerides in the blood) is linked to coronary artery disease.

Question 5

What is Hypertriglyceridemia?

Answer 5

Excess volume of triglycerides in blood

Question 6

What is the Circulatory System?

Answer 6

● Responsible for delivery of cells’ supply of oxygen, which is essential element for all chemical processes, including digestion.
● Transports nutritive particles such as glucose from digestive tract to body tissues
● Transports metabolic wastes from tissues to organs of re-processing or elimination (lungs, kidneys, liver)

Question 7

What is Liver?

Answer 7

● Produces bile (needed to break down ingested oils/fats)
● Glucose regulation: can build glucose (from fatty acids) & break it down, also converts glucose into storage form GLYCOGEN
● Stores vitamins & minerals
● Synthesizes proteins for use in body
● Helps build & break down fat stores
● Metabolizes hormones & drugs
● Converts fatty acids into KEYTONES

Question 8

What are ketones?

Answer 8

When glucose supplies are low, body begins to break down fat cells for energy. Process produces fatty acids as by-product, some of which are essential to metabolism, but some are quite dangerous to health. Liver can convert fatty acids into ketones, which can keep heart, brain & muscles fueled. However, ketones are acidic (lower pH of body fluids). Ketone build-up blood, called ketoacidosis, can be life threatening.

Question 9

What is ketoacidosis?

Answer 9

Ketone build-up blood

Question 10

The preferred cellular fuel source is?

Answer 10

*Glucose.
If glucose availability is insufficient, amino acids, fatty acids & triglycerides are utilized. Glucose utilization is less complex & most efficient, & involves the fewest potentially detrimental by-products.

Question 11

What is the pancreas?

Answer 11

Part of endocrine system, large gland with several major roles to play in digestion & glucose dynamics.

● synthesizes digestive enzymes involved in breaking down of all digestible food types

In addition to helping break down proteins, fats & starches, pancreas also helps neutralize chyme. Chyme (thick semi-fluid mass of partly digested food) passed from stomach to duodenum. Acidity has potential to damage walls of small intestine if pH is not balanced.

● synthesizes hormones involved in blood glucose
regulation

→ alpha cells release GLUCAGON in response to low blood glucose
→ beta cells release INSULIN in response to high blood glucose
→ delta cells (along with various other sources) release SOMATOSTATIN, regulator hormone. It’s employed to oversee endocrine gland activities, by inhibiting hormone secretion. Influences release of many hormones, e.g., growth hormone, digestive hormones like gastrin & secretin, glucagon & insulin. So, it can control processes Eg. stomach emptying & nutrient digestion, absorption & utilization. These hormones are produced in area
of pancreas tissue called ISLETS OF
LANGERHANS.

Question 12

What is insulin?

Answer 12

● hormone that creates ‘well fed’ state in body; without insulin body cannot get energy it needs from food it consumes
● released in response to GI enzyme levels (part of digestive cycle), to high blood glucose, & to parasympathetic nervous system stimulation
● facilitates passage of glucose from bloodstream into cells by stimulating cell wall insulin receptors
N.B. Blood cells, most brain cells do not require insulin for glucose uptake.
● increases uptake of amino acids by cells

Question 13

What is the function of Insulin?

Answer 13

● anabolic in function:
→ stimulates conversion of glucose not needed immediately into its storage form glycogen; glycogen storage occurs in liver, where it’s accessible to body as needed, & in muscle cells, for future use by muscle
→ stimulates liver to convert excess glucose to fatty acids & then to triglycerides
→ stimulates conversion of amino acids to proteins

After meal, glucose moves from intestinal tract into blood. With rising blood glucose level, insulin is released to promote movement of glucose molecules into tissue cells, where they are used for energy production. Insulin then prompts liver to either store remaining excess blood glucose as glycogen (for short-term energy storage) and/or use it to produce fatty acids. Excess fatty acids are synthesized into triglycerides to form basis of adipose, more concentrated, longer term form of energy storage.

Question 14

What is Glucagon?

Answer 14

● creates ‘find food’ state in body
● released in response to low blood glucose & to SyNS stimulation (stress connection)
● catabolic in function:
→ facilitates conversion of liver glycogen stores to glucose
→ facilitates breakdown of amino acids & stored fat (adipose)

Question 15

What is Diabetes?

Answer 15

Disorder of carbohydrate, protein & fat metabolism resulting from an imbalance between insulin availability & insulin need.

Question 16

What is Diabetes mellitus?

Answer 16

Metabolic disease characterized by disordered insulin kinetics – either there is insufficient insulin produced for body’s needs, or insulin is poor quality, or there are problems with uptake of insulin by tissue cells.

All types have significant family inheritance connection. Some ethnic groups have been identified as having higher diabetes incidence, eg, North American indigenous peoples, Hispanics, Asians, African Americans.

What’s inherited is susceptibility to becoming diabetic. Triggering element is typically needed to activate disease. This may be illness or other stressor. Lifestyle factors are also substantial component in some cases.

Without healthy insulin kinetics, glucose cannot enter most of body’s cells. Without glucose, cells are malnourished & impaired in performance of their
functions. Blood glucose levels rise to unhealthy
levels (hyperglycemia), which causes various types of metabolic stress. There are numerous ramifications & secondary effects of these basic realities of diabetes.

Question 17

What are Diabetes Diagnostic Criteria?3

Answer 17

1. Fasting blood glucose (FPG)
   Must not eat or drink anything except water for at least eight hours before this test. Test result of 7.0 mmol/L or greater indicates diabetes (6.1 – 6.9 for prediabetes).
2. Casual blood glucose
   Test may be done at any time, regardless of when you last ate. Test result of 11.0 mmol/L or greater, plus symptoms of diabetes, indicates diabetes.
3. Oral glucose tolerance test
   You will be given special sweetened drink prior to blood test. Test result of 11.1 mmol/L or greater taken two hours after having sweet drink indicates diabetes (7.8 – 11.0 for prediabetes).

A second test must be done in all cases (except if you have acute signs & symptoms).

Question 18

What is A1c?

Answer 18

Hemoglobin A1c (HbA1c or just A1c) is current standard for measuring body’s management of blood glucose. Reflects average blood glucose level over past 2-3 months. What is being measured is percentage of glycated hemoglobin (red blood cells with sugars irreversibly attached). Since rbcs have lifespan of approximately 3 months, A1c reading tells a story.

Does not provide info about day-to-day glucose ups & downs, so is not used for that type of monitoring responsiveness. It’s used, along with tests, to confirm diabetes diagnosis. Also seen as an indicator of risk to kidneys, eyes, & blood vessels. Reducing an elevated A1c by even point lowers risk of damage to these structures.

Taken in standard medical blood test. Measured as a percentage: ˂5.7% is normal, 5.7-6.4% is prediabetic, & over 6.5% is diabetic. Goal for person with diagnosed diabetes is to keep A1c well under 8%, less than 6.5% if possible. Age does not affect
A1c, but people may have different goals. Eg, younger diabetic may be more focused on reducing long-term body system complications & an older person more focused on minimizing blood sugar highs/lows. Presence of other conditions (e.g., anemia), drugs, etc., that influence rbc turnover can alter A1c readings.

Question 19

What is Type 1 Diabetes?

Answer 19

Believed to be autoimmune condition in which
beta cells of pancreas are attacked.

With beta cell destruction pancreas produces little or no insulin
● result is dangerously high hyperglycemia
● life-threatening condition that was quickly fatal before discovery of insulin
● not curable; person is dependent on external
insulin source
● Type 1 diabetics are 5-10% of diabetic population
● onset usually in childhood (used to be called juvenile diabetes), typically before age 30

Question 20

What is Type 2 Diabetes?

Answer 20

● 90-95% of diabetic population
● onset is usually over 40, although childhood onset is on rise
● multiple causation
● in some cases, problem is low or poor quality insulin supply
● in other cases, body cells develop decreased insulin sensitivity, i.e., reduced responsiveness of insulin receptors (INSULIN RESISTANCE)
● obesity connection is very strong in insulin resistance (80-90% of Type 2 diabetics are overweight)
● inadequate physical activity is risky co-factor (diet & exercise are both involved in controlling blood glucose)
● smoking – nicotine alters insulin effectiveness
● circadian rhythm disruptions from sleep deprivation or shift work can accelerate development of Type 2 diabetes
● person takes oral medications to increase pancreatic insulin production &/or to improve insulin receptor sensitivity; about 30% need to use insulin from outset, or eventually as condition progresses

Question 21

What is Gestational Diabetes?

Answer 21

● occurring in pregnant individuals who were not diabetic before becoming pregnant; is onset of hyperglycemia during pregnancy
● affects on average 4% of pregnancies, with as much as 20% incidence in at-risk populations
● onset is generally at around 24 weeks
● usually occurs in people with diabetic family tendency
● other key risk factors are obesity & age over 35
● use of corticosteroid medication increases risk
● diagnosis of gestational diabetes with previous pregnancy increases risk, as does prediabetes diagnosis
● placental hormones tend to naturally promote insulin resistance; susceptible individuals can become temporarily diabetic
● may require insulin or oral medication, depending on case
● affected moms are often candidates to develop Type 2 diabetes later on; as are their babies in later life
● baby is often quite large as result of extra blood glucose

Question 22

What is Prediabetes

Answer 22

● impaired fasting glucose or impaired glucose tolerance creating blood glucose at level that is approaching diabetic diagnosis but not yet there
● unless corrective measures are taken, tends to progress to Type 2 diabetes – losing as little as 5% of body weight & moderately increasing physical activity can make a significant difference
● current research says that damage to body, esp. to heart & blood vessels & to peripheral nerves, begins during prediabetes (not so much warning sign as an early stage)
● people are generally unaware that they have prediabetes, so screening is important, especially for those with identified Type 2 diabetes risk factors
● Diabetes Canada: current estimate is that 5.7 million Canadians have prediabetes (1 in 3-4 adults)
● given prevalence of prediabetes its recommended
everyone is screened at age 40 & every three years after that, those with higher identified risk should start earlier & screened more frequently (set individual schedule with MD)

Question 23

What is Metabolic Syndrome (AKA Syndrome X)?

Answer 23

insulin resistance, prediabetes & metabolic syndrome are closely related; having metabolic syndrome significantly increases risk of developing Type 2 diabetes & cardiovascular disease
● Defined as having 3 or more of:
→ central (deep abdominal) obesity “apple-shaped”
→ blood pressure of 130/85 or higher
→ elevated fasting blood glucose
generally in prediabetes range
→ elevated blood triglycerides
→ high LDL cholesterol & low HDL cholesterol readings

Question 24

What are the causes of Metabolic Syndrome (AKA Syndrome X)?

Answer 24

causes are complex & not fully understood, obviously involve combination of inherited & lifestyle factors coalescing in disordered energy utilization & storage

● key contributors appear to be: genetics, age, diet (N.B. sugared beverage consumption), chronic stress, lack of exercise, smoking, alcohol overconsumption, mood disorder/related medication, insulin resistance & sleep apnea
● includes phenomenon of ectopic fat—fat stored in organs & muscles that are not designed for fat storage
● also associated with fatty liver disease, gout & hyperuricemia, rheumatic diseases, increased coagulation risk, polycystic ovarian syndrome, erectile dysfunction & increased dementia incidence
● its estimated that 20-25% of world adult population has some degree of metabolic syndrome, 30-35% in North America (40+% in
people over 60)
● although there is clear connection, metabolic syndrome & obesity are not synonymous; obesity without metabolic syndrome does not convey large cardiovascular risk, while metabolic
syndrome without obesity does
● metabolic syndrome, insulin resistance & prediabetes are not stages of one another, rather they are interconnected states

Question 25

What is Ectopic?

Answer 25

Process Occurring in an Abdominal Location