ch 7 energy balance and diabetes

Question 1

basic energy dilemma

Answer 1

• food intake is intermittent (not around the clock/irregular)
• glucose requirement, especially for nervous system, is continuous.
• therefore, the body must have a way to store and mobilize nutrients to maintain blood glucose at a constant level.
• most cells in the body can burn proteins, fats, or sugars (glucose) for energy except for cells in the nervous system!!
• they can only burn glucose long term!
• while these nervous system cells need glucose constantly, you don’t eat constantly, so we had to have a way to store glucose until a time when we need it
• lower blood sugar by moving glucose form the blood to cells
• raise blood sugar from cells to blood

Question 2

our bodies and glucose

Answer 2

• our bodies look at glucose the way we look at money or gold
• it wouldn’t matter how much you had, if I offered you more, you’d take it
• there will never be a time when our bodies dont store glucose
• glucose can be in 2 places in our bodies: in the blood or in the cells.
• we lower blood sugar by moving glucose from the blood to cells
• we raise blood sugar when we move sugar from our cells to blood

Question 3

how to raise/lower blood sugar

Answer 3

• move glucose from cells to blood (bc you check patients blood glucose to see how high it is)
• to lower it: glucose moves from the blood to the cells

Question 4

glycogen metabolism

Answer 4

• when glucose gets high in the blood, it gets assembled into a big molecule called glycogen
• glycogen: high glucose levels in blood (big molecules) short term energy AND is stored in our liver and skeletal muscle
• glycogen is used for short term energy: when there is no more room in our liver or skeletal muscle for glycogen, excess glucose gets assembled into fat and stored all over our bodies.
• glycogen gets broken down into glucose when blood sugar is low
• bld sugar is high = glucose –> glycogen = glycogenesis
• bldd sugar is low = glycogen –> glucose = glycogenolysis
• genesis = to create
• lysis = break apart

Question 5

gluconeogenesis

Answer 5

• making new glucose
• glycogen stores can be used up after a few hours of fasting
• new glucose molecules can be synthesized from proteins and fats – gluconeogenesis (synthesized fats and proteins by rearranging what they are made of: carbon, hydrogen, and oxygen)
• carried out by the liver
• if you cut out all of the sugars in your diet your nervous system still needs glucose. fats, proteins, and sugars are all made up of carbon, hydrogen, and oxygen. so making glucose from fats and protiens is all just a matter of rearranging these C, H, & O atoms
• gluconeogensis literally means “making new glucose”
• this has to happen to support the nervous system

Question 6

inside of cells, biomolecules can be:

Answer 6

• biomolecules: proteins, fats, and sugars
• can be broken down by cellular respiration to make ATP (happens in mitochondria)
• used to synthesize other molecules
• converted to energy storage molecules: glycogen (carbohydrate) and triglyceride (fat)
• they can also be used to for spare parts to build up other proteins, fats, and sugars that the cell needs
• they can be stored for energy (glycogen for short term and fat for long term 4-8 weeks)

Question 7

metabolic rate

Answer 7

• metabolism
• amount of energy (heat + work) released per unit time
• influenced by muscular activity, age, gender, and several other factors
• when people talk about how fast or slow their “metabolism” is, what they really mean is their metabolic rate.
• our bodies do not store ATP, we make ATP as we need it
• we store glucose because with glucose and oxygen we can always make more ATP
• meaning, if our bodies are making lots of ATP that means our bodies are using a lot of ATP which would be a fast metabolic rate
• the more muscle one has, the more contraction you do, the more energy is required
• hormones - promote weight gain
• testosterone - burn fat

Question 8

REVIEW SLIDE 7 AND 8

Answer 8

REVIEW SLIDE 7 AND 8

Question 9

basal metabolic rate (BMR)

Answer 9

• metabolic rate of person who is awake, lying down, physically/mentally relaxed, and fasted for 12 hours = rate of oxygen consumption
• roughly equal to rate of oxygen consumption
• making a lot of ATP –> people who use a lot of ATP = high metabolic rate
• oxygen is used at the end of the electron transport chain during cellular respiration. we need oxygen to make the majority of the ATP that we use. the more oxygen we use, the more ATP we are making which is a reflection of how much ATP we are using. this is our metabolic rate

Question 10

energy balance

Answer 10

• energy stored (weight gained) = energy input (how many calories we ate that day) - energy output (how many calories we used that day)
• energy output = work performed + heart released
• if energy stored is a negative number –> lose weight
• if energy stored is a positive number –> gain weight
• first law of thermodynamics: energy cannot be created or destroyed. so this is the simplest equation to explain weight gain or loss

Question 11

energy balance

Answer 11

• positive energy balance: energy input (calories ate that day) > energy output) calories being used
• calories ate are greater than calories used
• negative energy balance: energy inout < energy output
• calories ate is less than calories used
• if you eat more calories than you burn, energy will be stores in the form of fat
• lose weight = negative
• gain weight = positive

Question 12

energy balance

Answer 12

• generally, body is not in energy balance
• absorptive state: 3-4 hours following meal, positive energy balance, energy stored
  cells will assemble glucose into glycogen (big molecules) and use the excess energy to build fats and proteins
• postabsorptive: between meals, negative energy balance, energy mobilized. glucose sparing (most cells metabolize proteins and fat saving glucose for the nervous system
• if its been more than 4 hours since your last meal, your body enters the postabsorptive state. bc glucose is needed for the nervous system, the other cells in the body begin to burn protein and fat so that any glucose can enter the bloodstream and be sent to the cells in the nervous system
• the longer your body stays in the postabsorptive state, the more fat you will burn

Question 13

adipocytes/ adipose tissue

Answer 13

• adipocytes: cells that specialize in storing fat
• adipose tissue: is fat and fat is used for long-term energy storage
• cells that store fat: triglycerides
• 20-30% of body weight (normal)
• can be up to 80% body weight
• 75-80% total energy reserves
• contains enough energy to last 2 months
• fat cells: 1/5 or 1/3 of mass (fat)
• 6-8 week until starvation mode

Question 14

how does your body know when to transition from postabsorptive state to absorptive state?

Answer 14

• transitions between post-absorptive and absorptive states regulated by hormones and endocrine system
• regulated primarily by:
• insulin: lowers bld sugar (taking glucose out of bld and putting into cells)
• glucagon: opposite of insulin: increases bld sugar
• epinephrine: raise bld sugar

Question 15

insulin

Answer 15

• promotes synthesis of energy storage molecules
• anabolic (BUILD) hormones
• increased release during absorptive state (bld glucose levels high)
• decreased release during post-absorptive state (bld glucose levels low)
• produced by beta cells in islets of langerhans in pancreas
• insulin: lowers bld sugar and moves glucose out of the bld and into cells
• insulin: produced by beta cells in pancreas

Question 16

how does insulin get out of the bld and into our cell? glucose uptake

Answer 16

• glucose: large polar molecule and will not cross plasma membrane without transport protein
• glucose transport protein 4 (GLUT 4) is the transport protein
• transport protein = GLUT 4 (not normally in the membrane, if it were, glucose would be constantly moving out of our cells which would lead to low bld sugar
• sensitive to insulin
• insulin increases GLUT4 membrane expression and synthesis
• GLUT 4 is only in the membrane when it tells it to be and once its in the membrane glucose can enter the cell and not be in the bld anymore
• when insulin gets released from beta cells in the pancreas, it binds to insulin receptors on normal body cells and causes GLUT 4 to be inserted to the membrane which allows glucose to move from the bld into the cell

Question 17

glucagon

Answer 17

• glucagon (opposite of insulin and raises bld sugar): breaks down glycogen to raise the bld suger
• antagonist to insulin
• catabolic hormone
• decreased release during absorptive state (glucose levels high)
• increased release during post-absorptive state (glucose levels low
• secreted by alpha cells in pancreatic islets of langerhans in the pancreas

Question 18

glucagon pt 2

Answer 18

• glucagon gets released during the postabsorptive state when bld sugar is low
• catabolic means “breaking down” bc thats mainly what glucagon does
• it signals to stop building molecules like fat and protein, for normal cells to burn fats and proteins for energy (saving glucose for the nervous system) and to break down glycogen to raise the bld sugar
• not enough insulin = diabetes
• hypoglycemia = low bld sugar
• more than 4 hours since last mean –> lets break down glycogen fats and proteins and get glucose to the brain!

Question 19

review slide 19

Answer 19

review slide 19

Question 20

bld glucose regulation

Answer 20

• hyperglycemia: fasting (no food 9-12 hrs) bld glucose > 140 mg/dL indicative of diabetes mellitus (high bld sugar)
• hypoglycemia: fasting blood glucose < 60 mg/dL, bad for CNS (low bld sugar)
• 100 mg is pretty normal bc its the midline of the two

Question 21

A1C

Answer 21

• when glucose enters your bldstream, it attaches to hemoglobin in your red bld cells
• A1C is a measure of the percentage of your red bld cells that have glucose-coated hemoglobin
• your A1C levels are essentially a representation of your average bld sugar levels for the past 3 months

Question 22

epinephrine

Answer 22

• also known as adrenaline
• sympathetic nervous system product
• suppresses insulin, stimulates glucagon
• promotes post absorptive processes
• primarily important during stress reactions, energy for fight or flight
• someone who carries an epi pen for allergies is carrying around a syringe filled with adrenaline to be injected if they are exposed to an allergen
• epinephrine does the exact same thing as glucagon: it prepares you for fight or flight.
• if you run you will need lots of energy “glucose”
• epinephrine does many things but primarily it rasies your bld sugar so that your nervous system cells can function under these stressful conditions

Question 23

diabetes mellitus

Answer 23

• 8% of americans (24 million people) are diabetic
• another 57 million are pre-diabetic
• 7% of world population (260 million people) are diabetic)
• pre diabetic means that cells are becoming resistant to insulin. this is a result of weight gain
• there is type 1 and 2
• the vast majority of diabetes is causes by cells becoming resistant to insulin not lack of insulin produced

Question 24

type 1 and 2 diabetes

Answer 24

• type 1: (insulin-dependent diabetes mellitus), juvenile-onselt, 5-10%
• type 2: (insulin-independent diabetes mellitus), adult-onset, 90-95%
• type 2 is usually a result of obesity which mostly happens in adults, though there has been an alarming number of cases in juveniles in recent years

Question 25

type 1 diabetes mellitus

Answer 25

• autoimmune disease
• immune system destroys beta cells of pancreas–loss of insulin secretion
• partially genetic
• may also be triggered by viral infection
• people with type 1 diabetes simply do not produce enough insulin due to damage to pancreatic cells
• they must inject insulin or have an insulin pump installed to mange their bld sugar level

Question 25

type 2 diabetes mellitus

Answer 25

• target cells throughout body do not respond well to insulin
• larger genetic factor than type 1
• lifestyle/obesity also play a large role (BMI body mass index > 25)
• type 2 poduce enough insulin bc there is nothing wrong with their pancreas however due to obesity their cells are already full of glucose. so when insulin binds to insulin receptors and GLUT 4 gets inserted into the membrane, glucose does not enter. it stays in the bld resulting in chronic high bld sugar
• larger genetic factor bc obesity is believed to be more closely related by genetic than autoimmune diseases
• if both parents are obese, child is statistically more likely to be obese. whether its due to genes or lifestyle or environmental factors its still unclear which
• however most researchers believe its both

Question 26

acute (sudden) effects of diabetes

Answer 26

• ketoacidosis: pH in bld gets too low due to build up acidic ketones 9direct result of hyperglycemia (high bld suger)
• hyperosmolar non-ketotic coma: coma resulting in very high bld sugar w/ normal ketone levels
• hypoglycemic coma: diabetic coma due to dangerously low or high bld glucose levels

Question 27

ketoacidosis

Answer 27

• decrease in bld pH due to buildup of acidic ketones
• direct results of hyperglycemia
• think of glucose as the supreme unleaded gas. its the best fuel. if you could afford to, that’s all you would put in your car
• if your cells could burn only glucose, they would bc its the cleanest burn.
• but cells also burn proteins and fats. the problem with that is that proteins and fat produce ketones that lower the pH of the bld.

Question 28

how does decreased insulin lead to ketoacidosis

Answer 28

• decreased insulin –> increase bld glucose (hyperglycemia) increase fat and protein metabolism
• high bld sugar means glucose levels remain high in bld and low in cells
• cells must break down fats and proteins for energy which results in the production of ketones
• if sugar is high in the bld then its typically low in the cells. so cells burn proteins and fats for energy which results in ketones that make the bld acidic. this can lead to coma or death

Question 29

hyperglycemia causes increased urine output

Answer 29

• one of the main symptom of juvenile-onset diabetes is increased urination which is why parents take children to the doctor
• our kidneys help clean our bld by removing toxins and drugs but also anything that we have an excess of in our bld
• if bld sugar is too high, there is an excess so it gets filtered out into our urine
• with more glucose in our urine, water will move into our urine bc of osmosis this increases the volume of urine, resulting in increased urination
• before anyone knew diabetes was a thing, individuals wrote about a condition in which urine had a sweet taste to it. this was the glucose

Question 30

hyper-osmolar non-ketotic coma

Answer 30

• some elderly patients forget to monitor their bld sugar properly
• chronic high bld sugar leads to increased urination, leads to dehydration, then bld thickens, leads to thick bld clots, leads to coma
• in conclusion, bld being too thick

Question 31

hypoglycemic coma

Answer 31

• accidental insulin overdoes as part of diabetes treatment
• decreased bld glucose
• nervous system damage
• HYPO=LOW
• bld sugar is high = inject insulin
• after pricking finger everyday and taking insulin for years, pts get in a habit of doing it at the same time each day and some choose to skip pricking finger and inject without checking
• depending on physical activity, age, meals, and many other factors, bld sugar might not even be high and insulin was still injected
• insulin LOWERS bld sugar and if its already low and you inject insulin, it can get dangerously low that can cause coma or death
• never inject insulin without checking, you could kill them
• if someone is having a seizure or is disoriented, its way more likely that their bld sugar is low not high. if their bld sugar is low give them a glass or orange juice (wont kill them but insulin will)