Exam #2 Flashcards
(244 cards)
1
Q
What is the basics of metabolism and what occurs?
A
ATP hydrolysis
- ATP converts to ADP + Pi via myosin ATPase
2
Q
What type of molecule is ATP? Where does it come from?
A
ATP: large, hydrophilic molecule
ATP is formed through the foods we consume (CHO, protein, and fats) that become stored energy → ATP
3
Q
What is the storage form of carbohydrates? Where are the two areas they can be found?
A
Glycogen - storage form of carbohydrates
Found: Liver and skeletal muscle
4
Q
What is the transport form of carbohydrates? Where can it be found?
A
Glucose - transport form of carbohydrates
Found: In bodily fluids (blood!)
5
Q
Where are the two areas that fat can be found?
A
- Subcutaneous (under skin) and visceral (around organs)
- Intramuscular
6
Q
Between carbohydrates and fats, which is more storage efficient in energy source?
A
Fats
7
Q
What are the three sources of potential energy in our body?
A
- Glucose
- Glycogen
- Triglycerides
8
Q
What type of form of CHO is glucose and what is it composed of?
A
Glucose - transport form of carbohydrates
Composed of 6 carbon base compund
9
Q
What type of form of CHO is glycogen and what is it composed of?
A
Glycogen - storage form of carbohydrates
Simply composed of glucose molecules linked together (1-4 link + 1-6 link)
10
Q
What type of exercise intensity can carbohydrates support?
A
Can support high intensity exercise >50% VO2max
11
Q
What is a triglyceride and what is it composed of/its structure? How much potential energy does it have compared to glucose?
A
- Triglyceride is a form of fat with a glycerol backbone and 3 fatty acids (FA)
- Composed of a 16 carbon compound molecule
- Has a much higher source of potential energy compared to CHO
12
Q
What type of exercise intensity can fats support up to?
A
Slow intensity exercise up to 50% VO2max
13
Q
Even though fats have a lot more potential energy than carbohydrates why does it support a smaller VO2max than carbohydrates?
A
Since fats have a greater number of carbon, fats have to undergo more steps to be oxidized compared to carbohydrates.
14
Q
What is the most common triglyceride in mammalian tissue?
A
Palmitate
15
Q
What type of metabolic pathway does the body use in a 2-3 sec. exercise? Why does it use this substrate and what type of exercise intensity could this individual be doing?
A
ATP
- ATP should be readily available in the sarcoplasm
- Only 1 simple explosive moment (standing up from a chair, pushing something over your head)
16
Q
What type of metabolic pathway does the body use in a 15-20 sec. exercise? What type of exercise intensity could this individual be doing?
A
ATP/CrP
- High intensity exercise
- 100m sprint
17
Q
What type of metabolic pathway does the body use in a 2-3 minute exercise and why? What type of exercise intensity could this individual be doing?
A
(Fast) glycolysis
- ATP production is a bit lower as it consists a bit more steps of metabolizing carbohydrates = CANNOT support as high intensity of an exercise
- 800m
18
Q
What type of metabolic pathway does the body use if one was to exercise for hours? What type of exercise intensity could this individual be doing and distinguish which substrates is responsible for a long period of low intensity exercise and explain why.
A
Oxidative system (slow/aerobic glycolysis)
- Consists of FULLY metabolizing carbohydrates and fats
- Supports exercise for long hours, however at a low intensity, especially fats
~ Fats have higher number of carbon, thus having to undergo more steps of being able to extract the full potential energy that can support that exercise
- Marathon
19
Q
What is hormone sensitive lipase (HSL)?
A
Hormone sensitive lipase: an enzyme that is found on the glycerol backbone of a triglyceride
- Breaks the fatty acids off the glycerol backbone = converting triglyceride to glycerol and 3 FFA
20
Q
What is that preparation process for fatty acids in the mitochondria?
A
B-oxidation
21
Q
Where does glycolysis occur?
A
In the sarcoplasm of the muscle fiber
22
Q
What is the first intermediate of glycolysis and its compund? What is the last intermediate of glycolysis and its compund?
A
First intermediate - G6P ; glucose-6-phophate (6 carbon compound)
Last intermediate - Pyruvate (3 carbon compound)
23
Q
Trace the pathway of (fast) glycolysis. How is glycogen flux maintained as exercise prolongs and where does it come from? What enzyme does it use?
A
Glycogen (prolonged exercise = stored glycogen depletes)
↓
G6P (first intermediate of glycolysis) ← Glucose (from bloodstream to muscle via Hexokinase)
↓
Pyruvate
↓
HLa (lactic acid)
24
Q
(a) What enzyme is used to convert glycogen into glucose-1-phosphate?
(b) What is this process also called?
(c) What is this enzyme also activated by and where do they come from?
A
(a) Glycogen phosphorylase
(b) glycogenolysis
(c) Ca2+ from the skeletal m. is the primary activator, and the catecholamines from the liver
25
What is hexokinase?
An enzyme that allows (blood) glucose to pass through the cell membrane of the muscle fiber
26
What is the most simplest metabolic pathway in the skeletal muscle and why?
Creatine kinase / PCr metabolic pathway
Why? - It includes only one enzyme
27
Trace the phosphocreatine (PCr) metabolic pathway? What activates the enzyme involved? What are the byproducts? What can the byproducts of this metabolic pathway also form?
Creatine kinase (enzyme; activated by hydrolysis products of ATP)
↓
breakdown phosphocreatine
↓
By-products: Creatine + Pi + Free energy
Pi (from PCr) + ADP (in the muscle fiber) = ATP!
28
What happens/is the relationship between the ATP/PCr metabolic pathway during rest to high intensity exercise? What happens after 8 seconds into high intensity exercise?
- At resting value, ATP and PCr is at 100% within the muscle fiber
- When high intensity exercise starts, the percentage of ATP is maintained, but PCr depletes
- Why? - PCr is active during this time and is being used while also maintaining ATP
- After 8 seconds in, all of PCr has been used, and ATP will start to deplete
- Exhaustion/fatigue sets in after 14 seconds
29
Detail how PCr is resynthesized in the skeletal m. post-exercise from the aerobic production of ATP with the given time of 1 min, 3 mins, and 5 mins.
- Post-exercsie = individual breathes heavily
- Aerobic production of ATP becomes PCr in sarcoplasm
- 1 min post-exercise = 50% resynthesizes
- 3 mins post-exercise = 80% resynthesizes
- 5 mins post-execise = 100%
30
List the number of electron carriers that are produced during "fast" glycolysis starting from glucose to pyruvate.
- 2 NADH
31
How much ATP is produced in the "fast" glycolysis of glucose vs glycogen? Why?
2 ATP produced for glucose
3 ATP produced for glycogen
- Glycogen is already stored in the muscle cell, thus does not have to invest ATP to bring glucose in the cell.
32
What is phosphofructokinase (PFK)? When does this enzyme appear? What activates and inhibits this enzyme? Which investment of ATP is this for glucose and glycogen?
Phosphofructokinase (PFK): a rate limiting enzyme that must be activated in order for the glycolytic pathway to occur/continue
- Appear when G6P converts to pyruvate
- (+) Activated by: contractile activity products (ADP, Pi)
- (-) Inhibited by: ATP and citrate
- 2nd investment for glucose, 1st investment for glycogen
33
Which enzyme causes the true splitting of sugar in glycolysis? What does this result in?
Aldose
- Splits the 6-carbon compound of glucose into 2 3-carbon compound
34
How many pyruvate do we get at the end of (fast) glycolysis?
2 pyruvate
35
Where does the oxidative / "slow" glycolysis metabolic pathway occur?
In the mitochondria
36
Trace the pathway of (slow) glycolysis / oxidative metabolism starting from pyruvate. Distinguish what's the first intermediate of this pathway.
Pyruvate
↓ Enters mitochondria
AcCoA (first intermediate of oxidative pathway)
↓
Kreb Cycle
↓
Electron Transport Chain (ETC)
↓
ATP!
37
How many Acetyl-Coenzyme A do we have coming from the oxidation of CHO vs fats? Why?
CHO - 2 AcCoA
Fats - 8 AcCoA
- Fats have a higher number of carbon ions (16) compared to the carbohydrates 6 base carbon compound
38
(a) What determines the number of turns of the Kreb Cycle?
(b) How many NADH do we get per turn of the Kreb Cycle?
(c) How many FADH2 do we get per turn of the Kreb Cycle?
(d) How many ATP is produced per turn of Kreb Cycle?
(e) What's the product/first intermediate of the Kreb Cycle?
(f) What products of the Kreb Cycle goes to the electron transport chain (ETC) to produce ATP aerobically?
(a) The # of ACCoA in the mitochondria
(b) 3 NADH
(c) 1 FADH2
(d) 1 ATP
(e) Citrate
(f) ALL electron carriers produced enters the ETC (NADH + FADH2)
39
What is isocitrate dehrydogenase and where is it found? What will activate and inhibit this enzyme?
Isocitrate dehydrogenase is the rate-limiting enzyme in the Kreb Cycle
- Must be activated in order for fat + carbohydrate oxidation to continue
- (+) Activated by: contractile activity products (ADP, Pi)
- (-) Inhibited by: ATP
40
What is the relation of O2 and CO2 with the Kreb Cycle? What is used or not used? What is being produced?
In the Kreb Cycle:
- NO O2 is used
- Produces CO2
41
What is the last step/molecule required in the ETC in order for ATP to be produced aerobically in the oxidative system? What is it also called?
Oxygen
- "The last terminal electron acceptor"
42
What enzyme is used for the electron transport chain?
Cytochrome oxidase
43
Oxidative phosphorylation is also known as...?
The aerobic production of ATP
44
(a) What enters the ETC?
(b) For every NADH that enter the ETC, how many ATP will be produced aerobically?
(c) For every FADH2 that enter the ETC, how many ATP will be produced aerobically?
(d) Which electron carrier produces a smaller amount of ATP and why?
(a) Electron carriers (NADH + FADH2)
(b) 3 ATP is produced aerobically for every NADH that enters the ETC
(c) 2 ATP is produced aerobically for every FADH2 that enters the ETC
(d) FADH2; It enters the ETC at a lower energy state than NADH
45
What is the total energy yield of ATP for glucose? How about for glycogen? Why?
Glucose total energy yield = 38 ATP
Glycogen total energy yield = 39 ATP
Glycogen DOES NOT have to invest in ATP for glucose to enter in the muscle cell
46
Give a simple pathway/overview of fat metabolism?
Fats(FFA) → B-oxidation → (8) Acetyl CoA → Krebs cycle → ETC → ATP!
47
After being hydrolyzed by HSL, what proteins do fatty acids bind to able to travel in blood?
Albumin
48
How many Acetyl CoA is produced when going through the fat metabolism pathway and explain why? Thus how many turns does the Kreb Cycle go through?
8 ACCoA; due to 16 carbon compound from triglycerides, more ACCoa is produced from fats compared to carbohydrates
- Kreb Cycle will turn 8 times
49
(a) What is the total energy yield of ATP produced from a single FA?
(b) What is the total energy yield of ATP produced from all 3 FA?
(c) How much ATP does glycerol produce?
(d) What is the total energy yield of ATP produced from the complete oxidation of fats?
(e) Why can't fat support high intensity exercise? But what can it maintain?
(a) 129 ATP
(b) 387 ATP
(c) 19 ATP
(d) 406 ATP
(e) Even though fats yield this much energy, it CANNOT support anything higher than 50% VO2max due to many steps it takes to fully oxidize fat. But it CAN maintain/produce prolonged exercise
50
What is calorie referred to and what is it actually?
"Calorie (C)" is what we refer to in food
- It's actually a kilocalorie (c)
- 1 kilocalorie (c) = 1 calorie (C)
51
What is a kilocalorie? What is heat synonymous with?
The amount of heat required to raise the temperature of 1 kilogram of water one degree Celsius
- heat = energy
52
What is a direct calorimetry and what does it determine? What is it only useful for? Name an example of a direct calorimeter?
Direct calorimetry is able to measure the energy expended by allowing the subject to be inside this structure. The heat that is being produced and released by the subject will be measured, which can then determine what their kcal burn is.
- ONLY USEFUL for resting BMR
- Bomb calorimeter
53
List out the pros (2) and cons (4) for direct calorimetry.
Pros:
- Accurate over time
- Good for RESTING metabolic measurements
Cons:
- Expensive, slow
- Exercise equipment adds extra heat
- Sweat creates errors in measurements
- Not practical or accurate for exercise = errors caused ; not practical for energy expenditure of exercise
54
What is used to measure energy expenditure during exercise and how?
Indirect calorimetry
- Estimates total body expenditure based on O2 used and CO2 produced
55
What is VO2?
VO2: volume of O2 consumed per minute
56
What is VCO2?
VCO2: volume of CO2 produced per minute
57
What can the measurements of VO2 and VCO2 be also used for? What calculation is used?
- These measurements are used to assess the fuel selection our body is making during exercise
- Respiratory exchange ratio / R-value
58
What is the calculation for respiratory exchange ratio (RER or R-value)?
RER = VCO2/VO2
59
What does R-value range from? What is the intensity at those range and what fuel source will you be predominantly using?
0.71 - 1.00
0.71 - Low intensity, predominantly using fats
1.00 - High intensity, predominantly using carbohydrates, but still oxidizing fats
60
What are two things that R-value can inform us of an individual?
1. Can help calculate what fuel source one is using in a given activity(fat, CHO, or both).
2. Give an indication of the training status of the individual (trained or untrained); from calculation of energy expenditure for a given activity
61
If two individuals were given different exercise intensity (one is running and the other walking), is caloric expenditure the same in a fixed distance or a timed distance? Why?
Caloric expenditure is still the the SAME in a FIXED DISTANCE even if two individuals were given different exercise intensity. Since the distance being covered is the same, both individuals will expend the same amt. of calories wether you walk or run
However, with a timed distance, the individual that is running is not only able to cover more distance than the individual walking, but also expend MORE calories per minute
62
What is more effective for weight loss, high intensity short duration exercise or prolonged low intensity endurance exercise? Why?
High intensity short duration is more effective for weight loss since the caloric expenditure per min is higher, thus being more efficient for weight loss compared to prolonged low intensity exercise. Furthermore, high intensity turns on the oxidation for both fats and carbohydrates
63
What will be the R-value for an individual that is aerobically trained? Why?
They will have a slightly lower R-value as they do not have to use as much oxygen to combust carbohydrates and fats.
64
If an individual goes from rest and start increasing exercise intensity, what is the first fuel they will be predominantly using? How long will they continue to rely on it?
Fats
- Up to 50% VO2max (maximal rate of fat oxidation)
65
If one is doing low intensity exercise, up to 50% VO2max, what is 100% of your fuel coming from?
Fats
66
As intensity of exercise increases, what happens to the rate of fat oxidation? What other fuel source will be implemented to sustain that exercise intensity?
The individual will continue to oxidize fat at that SAME RATE and SAME AMOUNT.
- But when working at a higher intensity, the individual will have to start adding/using carbohydrates, turning glycolysis on at a HIGHER rate.
* WE DO NOT CHANGE THE AMT. OF FAT, WE ARE JUST ADDING CHO!
67
(a) What is VO2max?
(b) What is it the the best single measurement of?
(c) What is it not the best predictor of? Give an example
(d) What is VO2max expressed in? What is it suitable for?
(e) What is VO2 max scaled/normalized for?
(a) Maximal O2 uptake
(b) Aerobic fitness (how much O2 one actually consumes)
(c) Not the best predictor of endurance performance
- Marathon runners have nearly identical VO2max , thus can't dictate who will win
(d) Expressed in L/min. Suitable for non-weight bearing activities
(e) Normalized for body weight
68
What is lactate threshold?
Lactate threshold: Point at which blood pyruvate accumulation increased markedly
- Pyruvate production rate > pyruvate clearance rate
69
How is lactate threshold measured? How is LT typically depicted in a graph?
- Measured by having the subject on a bicycle or treadmill and attaining a blood sample throughout while also increasing the workload
- Shown as a nonlinear increase
70
How does lactate threshold occur?
As exercise intensity increase, glycolysis is turned on at a high rate to be able to produce as many ATP.
- At some point, more pyruvate is produced than can be taken into the mitochondria, thus can cause an accumulation of lactate
- This is where we see the nonlinear increase of blood lactate concentration.
71
What is lactate threshold a good indicator of? Why? Give an example?
LT is a good indicator of potential for endurance exercise
- Why? An individual with a lactate threshold that occurs at a higher % VO2max may run faster for a longer period of time as they have LESS PYRUVATE accumulating
- Marathon runners who have a higher LT may run for a longer period of time than those who have a lower LT
72
What is lactate threshold usually expressed as?
Expressed as a percentage of VO2max
73
What is the lactate threshold for an untrained individual vs. trained individual?
UT: 50-60% VO2max
TR: 70-80% VO2max
74
What would be the lactate threshold for world-class elite marathon runners?
Can be as high as 88-92% VO2max
75
How does one self-select their running pace?
One selects a running pace that is at or below their lactate threshold
76
What is EPOC? What happens to O2 during and after exercise?
EPOC: Excess Post-Exercise Oxygen Consumption; the rate of O2 consumption that is relatively high and an excess from the given state of your activity (post-exercise)
- During exercise, consumption of O2 is at a steady-state
- At the end of exercise, O2 consumption remains relatively high as that is the amt. we would typically use if exercise was to continue
77
What are the 5 components of EPOC? Elaborate.
- Replenishing of the ATP/CrP stores
- Continued substrate cycling (glucose and FAs) = can still be used to produced ATP aerobically as the substrates don't just go away instantaneously
- Elevated rates of fatty acid oxidation
- Increased body (muscle) temperature = enzymes will work more efficiently with glycolysis + Kreb Cycle + ETC
- Increase levels of catecholamines in the blood ; takes a while for these hormones to be cleared from the blood
* EVERYTHING GRADUALLY REVERSES ITSELF
78
What are the 2 definitions of fatigue? How can it be reversed?
1. Decrements in muscular performance with continued effort, accompanied by sensations of tiredness
2. Inability to maintain required power output to continue muscular work at a given intensity
- Reversible by rest
79
What are two scenarios that fatigue can occur?
1. Short duration, high intensity
2. Prolonged endurance exercise
80
Describe the 2 factors that causes fatigue during short duration, high intensity exercise.
1. CrP depletion
- Fatigue sets in at 14 sec. due to muscle running out of CrP
2. Metabolic by-products (glycolysis is turned on at a high rate = fatigue sets in at 3-5 mins.)
- High amt. of pyruvate → Increased lactate concentration = Increase of [H+]
a. Decrease in pH = make muscle acidic (~6.4 pH)
b. Decreased rate of glycolysis (enzyme doesn't work in acidic environment)
c. Interferes with Ca2+ binding to troponin; H+ binds to troponin (competitive inhibition) = no contraction (fatigue)
81
Describe the factors that causes fatigue during prolonged endurance exercise (in terms of not adding anymore fuel and only with the fuel you start with)
* LOW LIVER + MUSCLE GLYCOGEN
* LOW BLOOD GLUCOSE
= RUN OUT OF FUEL
Occurs within 70% VO2max with 2-3 hours of exercise (marathon)
a. Glycogen depletion
1. Muscle glycogen levels
- As exercise continues, muscle glycogen levels gets lower, so it will have to start relying on the glycogen in the liver and the blood glucose in order to maintain that glycolytic flux
2. Liver glycogen levels
- Liver glycogen converts to glucose via glycogenolysis to maintain the blood glucose
- However, due to limited supply of glycogen in the liver, the blood glucose level will also go down later in the exercise.
- Therefore, the rate of liver glycogenolysis is LESS/SLOWER than the rate of blood glucose uptake by the muscle, resulting in blood glucose to also go down
- Fatigue sets in due to the inability to provide an adequate supply of fuel to the muscle
82
(a) What will happen to a marathon runner during the race after they have become fuel depleted?
(b) What fuel source did the runner run out of to complete the race at a high intensity?
(c) So what fuel source does the runner have to rely on now to finish the race?
(d) What are things that marathon runners can consume to maintain glycolytic flux during a race?
(a) They will finish the race but at a much lower rate and very low intensity.
(b) The runner ran out of carbohydrates (glycogen depleted)
(c) Runner now has to rely on fats which can now only support up to 50% VO2max
(d) Ingest carbohydrates
83
What does the endocrine system consists of?
1. The organ (gland) ; secretes the hormones
2. The substance released (i.e., hormones)
- Not much hormone is needed to get affect
3. The target tissue (has to have a specific receptor for the hormone in order for an effect to an occur)
84
How do we get adequate fuel delivery/fuel mobilization to our skeletal muscle during exercise?
Via hormonal control
85
What are the 2 family types of hormones?
Steroid and nonsteroid hormone
86
What are steroid hormones?
- Derived from cholesterol (from fat w/n body stored)
- Lipid soluble, diffuse through membranes
- Anabolic hormones = growth differentiate (transcription + translation of protein synthesis)
87
Describe the process of how a steroid hormone gets activated as it enters the cell.
1. Steroid hormone diffuses through the cell membrane easily and will bind to its receptors in the cytoplasm or the nucleus
2. The hormone-receptor complex will get activated w/n the nucleus, resulting in transcription and translation of the cell's DNA
88
What are nonsteroid hormones? What are the two groups of nonsteroid hormones?
- Not lipid soluble, cannot cross membranes
- Has to bind to a receptor located on the cell membrane to enter, and another for it to be activated
- Divided into two groups:
1. Protein/peptide hormones
2. Amino-acid derived hormones
89
Describe the process of how a nonsteroid hormone gets activated as it enters the cell. Consider the hormone that is needed to activate this system.
*Catecholamines will need to activate this system
1. Nonsteroid hormone binds to its receptor on the cell membrane, which will result in the activation of adenylate cyclase (converts ATP to cAMP)
2. From activation of cAMP, this leads to amplification of signals resulting in cellular changes and hormonal effects
90
What are two factors that regulate and control the release of hormone?
1. Intensity of exercise (↑ intensity = greater release of hormone for fuel mobilization; vice-versa)
2. Prolonged endurance exercise - fatigue mechanisms: hormones will ensure adequate fuel delivery to active muscle
91
What is gluconeogenesis?
"Creation of new glucose"
92
Where does gluconeogenisis occur?
Gluconeogenisis can occur w/n two places: liver (predominantly) + kidneys
93
What are the three carbon compounds that gluconeogenisis takes?
1. (MAINLY) Amino acids
2. Pyruvate
3. Lactate
94
Which part of the nervous system can only run on glucose?
CNS - Central nervous system
95
Determine the gland + location and its effect on fuel mobilization on the following hormone. Mention its fun fact:
Growth hormone
Gland and location: Pituitary gland, anterior lobe (base of brain)
Effect on Fuel Mobilization:
↑ lipolysis- GH activates the enzyme HSL
↑ liver gluconeogenesis
Post-exercise promotes muscle growth (can be an anabolic hormone post-exercise)
Hormone Fun Fact:
As intensity or duration of exercise ↑, the [hormone] released into the blood
96
What hormone is known as the "permissive hormone" and why?
Thyroxine (T4) and Triiodothyronine (T3)
- Permits other hormones to do their jobs and is NEEDED for other hormone to function properly
97
Determine the gland + location and its effect on fuel mobilization on the following hormone:
Thyroxine (T4) and Triiodothyronine (T3)
Gland and location: Thyroid Gland (midline of neck below larynx)
Effect on Fuel Mobilization: (T3 & T4 share similar functions)
↑BMR
- hypothyroidism (BMR is low = weight gain) vs hyperthyroidism (BMR is high = hard time gaining weight)
↑glucose uptake
↑glycolysis & gluconeogenesis
↑lipid mobilization
*Needed for other hormones to function properly
98
Which gland had direct interaction with the sympathetic nervous system?
Adrenal medulla
99
What innervates the adrenal medulla, resulting in the release of hormones?
Sympathetic nervous system
100
Determine the gland + location and its effect on fuel mobilization on the following hormone. Mention its fun fact:
Epinephrine and Norepinephrine (catecholamines)
Gland and location: Adrenal Medulla (atop of each kidney) - innervated by SYMPATHETIC NERVOUS SYSTEM
Effect on Fuel Mobilization:
*Released when the sympathetic nervous system is active
↑liver & muscle glycogenolysis (more glycogen breakdown in liver!)
↑lipolysis (will also activate HSL in adipocytes = fat mobilization)
Hormone Fun Fact:
Aerobic Training results in ↓ hormone levels at same Exercise Intensity (i.e., exercise is less stressful)
101
Which hormone is increased during the pre anticipatory response for exercise and why? What does it do?
Increased secretion of catecholamines due to SNS being activated during exercise
- Upregulates glycogenolysis
102
Why can an individual who is aerobically trained find exercise less stressful?
- Individual who is aerobically trained is under/less metabolic stress = less hormone circulation due to NOTNEEDING MUCH FUEL MOBILIZATION in a given exercise intensity vs. someone not aerobically trained
103
Determine the gland + location and its effect on fuel mobilization on the following hormone:
Cortisol (a glucocorticoid)
Gland and location: Adrenal Cortex (atop of each kidney)
Effect on Fuel Mobilization:
↑amino acid mobilization that supports gluconeogenesis; (mobilize A.A. away from skeletal m. and go to liver → A.A. will enter the metabolic pathway)
↑glycogen breakdown (in the liver!)
↑ lipolysis (will also activate HSL)
- Anti-inflammatory agent
104
What type of hormone is cortisol?
Catabolic hormone: break things down
105
Determine the gland + location and its effect on fuel mobilization on the following hormone:
Insulin
Gland and location: Pancreas (behind/below stomach)
Effect on Fuel Mobilization:
↑Glucose uptake and glycogen storage in muscle and liver
↑Fatty acid uptake and triglyceride STORAGE in muscle, liver and adipocytes
↑ Amino Acid uptake in cells (supports protein synthesis)
- Inhibits liver gluconeogenesis (If insulin is elevated = inhibits gluconeogensis since there's already adequate glucose in blood)
106
What type of hormone is insulin? When are insulin levels high and why? What is insulin involved in?
- Insulin is an anabolic hormone
- Elevated when fed and rested = state at which blood glucose levels are high
- Very involved in FUEL STORAGE
107
What hormones is considered the "counter regulatory hormone" and why?
Glucagon and Insulin
- They both have opposite functions from each other
108
When are glucagon levels elevated? What does it activate?
- Elevated when blood glucose levels are low (fasted state = lack of fuel)
- Activates all the enzymes that are part of the gluconeogenic pathway in the liver and bit of kidney
109
Determine the gland + location and its effect on fuel mobilization on the following hormone:
Glucagon
Gland and location: Pancreas (behind/below stomach)
Effect on Fuel Mobilization:
↑liver gluconeogenesis
↑liver glycogenolysis (assuming that one is in a fasted or energy depleted state = breakdown of glycogen in liver to maintain blood glycogen)
110
Between glucose and insulin, which hormone will deplete and which hormone will be maintained during exercise? Why?
Insulin will deplete within the onset of exercise due to the fuel that is stored is being used. Glucose will be maintained during exercise due to hormones doing their job. As insulin goes down, the other hormones will then have to work to mobilize fuel from the stored location
111
What are the four main hormones that assists in the mobilization of blood glucose/glycogenolysis? Which of the four hormones causes a big change of stimulating more glucose coming out the liver?
- Epinephrine and NE (catecholamines), glucagon, and cortisol
- Catecholamines
112
What are the three hormones that assist in gluconeogensis?
GH, T3 + T4, glucagon
113
What are the four main hormones that assists in the mobilization of fat?
Growth hormone, cortisol, epinephrine and NE (catecholamines)
114
Distinguish the 4 hormones responsible for lipolysis?
GH, T3 + T4, Cortisol, Catecholamines (Epinephrine and NOE)
115
What are the two hormones that regulate the plasma volume?
1. Anti-diuretic hormone (ADH)
2. Renin-Angiotensin-Aldosterone (RAA)
116
What is plasma? What status of the body is important for plasma volume?
Water component of blood
- Hydration is important
117
What activates ADH and describe its effect.
- Activated by: Increase of blood osmolality (due to sweating → blood plasma ↓) = dehydration
- Effect: ADH targets the kidneys to retain water (→ decrease urine output) to reestablish the normal plasma volume
118
What activates RAA and describe its effect.
- Activated by: Decrease of blood flow to kidney (due to dehydration) activates RAA system
- Effect: ALDOSTERONE works on kidneys to retain water to increase/maintain plasma volume
119
If glycolysis was to be turned on at a high rate for an untrained individual, what happens to pyruvate and why?
For an untrained individual, pyruvate will end up going becoming lactate acid.
- Due to not being adequately trained, the amount of pyruvate CANNOT be cleared into the mitochondria as efficiently compared to a trained individual
120
How can some individual muscle fiber adapt/transform?
Due to aerobic training
121
What does suboptimal mean in regards to an unaerobictally trained muscle?
Less concentrations of contents within a muscle cell will result in the muscle to not perform as well
122
In an aerobically trained muscle, what are the 4 skeletal muscle adaptations to aerobic training? Explain each one in detail.
1. Capillary density
In an aerobically trained muscle, there is 1 more capillary per fiber versus a non-aerobically trained muscle, thus increasing the delivery of O2 and fuel to skeletal m.
- Lactate in skeletal m. is cleared by capillaries
- CO2 produced in Kreb Cycle is cleared/taken by the capillaries and to the lungs
2. Myoglobin density
Due to increase of capillary density, there's an 80% increase of myoglobin concentration to compensate for the O2 being delivered to skeletal m.
- High amounts of O2 are able to be delivered to the mitochondria due to high myoglobin concentration
3. Mitochondrial density
Mitochondria is considered as the "factory" that produces ATP aerobically. Mitochondrial density is increased/network is expanded with a 100% increase.
- Increases the capacity for aerobic production of ATP by being able to turn glycolysis on at a high rate = the pyruvate being produced at this rate is able to enter the mitochondria = don't see lactate being accumulated until a greater %VO2max due to pyruvate being cleared by mitochondria
- Able to oxidize fat (B-ox) at a higher rate (and won't have to mobilize as much fat due to ↑IMTG in TR athletes) = allows more fat to enter the mitochondria
4. Oxidative capacity
- Increased rate of aerobic ATP production
- Oxidative enzymes associated with mitochondria (B-ox, K.C. ETC) will increase their enzymatic activity = increase rate of aerobic ATP production
- Moving pyruvate out of the sarcoplasm and into the mitochondria and going through the complete oxidation
- Because of B-ox occurring at high rate, citrate that is produced within the Kreb Cycle is able to inhibit activation of PFK, thus slowing the rate of glycolysis = less pyruvate produced (less accumulation of lactate)
- Muscle glycogen is used at a slower rate for aerobically trained muscle = fuel is not used as fast but still able to do the same workload
123
What are two things that occur in an aerobically trained muscle if no downstream changes occur from the myoglobin adaptions?
If downstream doesn't change →
1) Pyruvate can't move out of sarcoplasm
2) Can't produce ATP aerobically as you can't oxidize the fuel
124
Since an aerobically trained athlete has a higher ceiling of their VO2max, what can their fat oxidation support up to? Why?
Still 50% VO2max
- Even though their VO2max is higher, an aerobically trained athlete can work harder and will have to OXIDIZE MORE FAT in order to support their workload, thus not having to rely on glycolysis as much
- They can support higher absolute work rate albeit the relative workrate (50%) being the same
125
How long does it take to see the aerobic training adaptions to be expressed?
It requires years of training for adaptations to occur
126
What enzyme in the Kreb cycle can be used as a measure as a marker of aerobic activity in skeletal muscle?
Citrate synthase
127
Compare the oxidative capacity between the UT Type I muscle fiber versus the TR Type IIb muscle fiber. What does this mean?
The oxidative capacity/trainability of the Type IIb muscle fiber is unmatched for the oxidative capacity of the UT Type I muscle fiber.
- Wether trained or untrained, Type I muscle fibers will have the highest oxidative capacity out of all the fiber types
128
Can all fiber types be trainable?
Yes
129
What is necessary/required in order for aerobic adaptations to take place in the skeletal muscle?
Skeletal muscle has to be ACTIVATED electrically/recruited and generating FORCE(LOAD)/DO WORK in exercise in order for exercise signals to induce peripheral adaptions to occur
130
What type of training is key for the activation of all muscle fiber types?
Interval training or high intensity training
131
What happens to the oxidative capacity in muscle for athletes that are doing high intensity training?
The total oxidative capacity of the muscle fiber types increases
- High intensity training = activation of all muscle fiber types
132
What are the 2 metabolic adaptions that are occcuring due to aerobic training
1. Pyruvate/Lactate threshold
- Occur at a higher percent of VO2max
- Decrease pyruvate production, increase pyruvate clearance
- Allows higher intensity without pyruvate accumulation
2. Respiratory exchange ratio (RER)
- Decrease (of workload) at both absolute and relative submaximal intensities
- Increase rates of ATP production through B-oxidation/fat (aerobically trained skeletal m. can process fat effectively) = can sustain a higher workload, which will decrease reliance on glycolysis (don'e have to turn on glycolysis at a high rate)
133
What are 3 factors that are important in a training program/exercise prescription. Describe them and distinguish which is the most important.
Frequency
- Optimal: 3 to 5 days per week
Duration
- Optimal: 20 to 30 mins per day
Intensity
- Most important factor!
- Textbook recommendation: 70% VO2max (however, the problem is the likelihood of recruiting Type IIb muscle fiber is low)
* Muscle MUST be ACTIVE and performing WORK for adaptations to occur
134
What can anaerobic training also be referred to? What do they not require?
Plyometric, speed, and power activities
- Does not require O2
135
Can improvements in performance occur in an athlete that did anaerobic training?
Yes!
136
What should be considered when assessing changes in metabolic pathways?
Rate limiting enzyme activity
- Changes in activity proves that changes occur in the metabolic pathway system
137
What are the adaptions that DO NOT occur due to anaerobic training?
*NO CHANGES OCCUR IN THE KEY ENZYMES
*ATP-PCr system
- Little enzymatic change with training
*Glycolytic system
- Minor increase in key glycolytic enzyme activity with training (phosphorylase, PFK, LDH, hexokinase); but still doesn't change how pyruvate is cleared no matter the rate of glycolysis = not much change
138
Where exactly do the performance gains come from in anaerobic training?
Performance gains from:
- Increase in strength
- Recruitment patterns; neural patterns down skeletal muscle
- Buffering capacity; prevent changes in pH, sustaining H+ ions before accumulation occurs
139
What does blood volume (BV) refer to?
The volume of blood in the L ventricle
140
Trace the pathway/flow of blood in the heart
SVC + IVC → R atria → R ventricle → Pulmonary arteries (to the lungs) → Pulmonary veins (from the lungs) → L atria → L ventricle → out the heart to the rest of the arterial circulatory system
141
What is stroke volume (SV) and its formula?
Stroke volume (SV): volume of blood PUMPED OUT from L ventricle in one heartbeat; mL
SV = EDV — ESV
142
What is EDV?
The volume of blood in the L ventricle just before the heart contracts
143
What is ESV?
The amount of blood that remains in the L ventricle after the heart has contracted
144
What is cardiac output (Q) and its formula?
Cardiac output (Q): total volume of blood pumped per minute; L/min
Q = HR x SV
145
What are the three major functions of blood?
1. Transportation of O2, nutrients, waste (from compartment to compartment)
2. Temperature regulation (moves heat away from various compartments)
3. Acid-base (pH) balance
146
What is the blood volume for men and women?
Related to body stature
Men: 5 to 6 L
Women: 4 to 5 L
147
What is whole blood composed of?
Whole blood = Plasma (water component) + formed elements ( RBC - 99% ; WBC 1%)
148
What percentage does plasma makes up of the blood volume?
*Makes up majority of blood
55-60 % of blood volume
149
What does plasma consists of and its percentage?
- 90% water
- 7% protein
- 3% nutrients/ions/etc.
150
What percentage does formed elements makes up of the blood volume?
40-45% of blood volume
151
What does formed elements consists of and its percentage?
– Red blood cells (erythrocytes: 99%) ; makes up majority of it!
– White blood cells (leukocytes: <1%)
– Platelets (<1%)
152
What is hematocrit?
Hematocrit: total percent of volume composed of formed elements
153
What is the hematocrit for men and women?
Men: 42-45%
Women: ~38-42% (due to menstruation)
154
What gives the yellow color of plasma?
Albumin
- a plasma protein part of fatty transport
155
Under resting condition, where is majority of the blood located?
(64% of blood) Veins
156
How can blood location be changed in the body?
By the state of activity
157
Distinguish the differences between veins and arteries
Veins:
- Compliant
- Greater diameter
- Smooth m. is thin
- 2/3 of blood in veins at rest
Arteries:
- Wall is rigid and no distention = efficient for blood movement/transport
158
What is the splanchnic region?
- Region that represents all the organs in the gut
- Consists of: Liver, stomach, pancreas, and intestines
159
At rest, what is the cardiac output? Which parts of the body gets the most distribution and least distribution of blood flow?
Cardiac output = 5 L/min
Most distribution: Splanchnic and kidney
Least distribution: Skeletal m. and skin
160
During heavy exercise, what is the cardiac output? Which parts of the body gets the most distribution and least distribution of blood flow?
Cardiac output = 25 L/min
Most distribution: (PREDOMINANTLY) Skeletal m. and skin (variable depending on the environmental condition; hot is greater & cold is less)
Least distribution: Splanchnic and kidneys
161
What is the mechanisms that allows for blood to get redistributed from a resting state to an active state?
Intrinsic control of blood flow: Ability of local tissues (muscles) to constrict or dilate arterioles = alteration of blood flow
162
What are the structures in the arterioles that regulate the amount of blood that can flow through the capillaries(bed)?
Precapillary sphincter
163
What do the capillaries/capillary bed surround?
Muscle fibers
164
In an active muscle, what condition are the precapillary sphincters at? Trace the blood flow.
When muscle become active, the sphincters open.
Blood flow through capillaries (getting through muscle fibers) → capillary bed → venules → venous circulation
165
In a resting muscle, what condition are the precapillary sphincters at? Trace the blood flow.
When muscles are inactive, the sphincters are closed.
Blood flow through arterioles → venules →venous circulation
166
What causes the precapillary sphincters to open, resulting in increase of blood flow in muscle? Think of the intrinsic control of blood flow.
Intrinsic (LOCAL) control of blood flow - Metabolic mechanisms (VD; Vasodilation - arterioles OR venodilation - vein)
– Buildup of local metabolic by-products
– ↓ O2 ; when muscle starts to contract, PO2 decrease in muscle tissue
– ↑ CO2, K+, H+, lactic acid (specifically H+)
~ K+ is normally inside the muscle cell, but when muscle contracts, K+ gets released
167
What is the mechanism that causes the reduction of blood flow from the splanchnic region?
Extrinsic neural control of blood flow
168
What is the extrinsic neural control of blood flow and what causes it? What occurs during exercise and when exercise is over?
*Redistribution of flow at organ, system level so that blood can go to the skeletal m.
*Sympathetic nervous system innervates smooth muscle in arteries and arterioles
– Baseline sympathetic activity → vasomotor tone
– ↑ Sympathetic activity (during exercise) → ↑VC
~ Vasoconstriction in vascular system of splanchnic region to get blood in the active m.
– ↓ Sympathetic activity (when exercise is over) → ↓VC (passive VD = allow for return of blood to splanchnic region when one is at rest)
169
What does the venous return of blood refer to?
Blood that goes back to heart (via IVC and SVC)
170
What environmental context defies where the blood should go/be (heart)?
Gravity
171
What can the heart pump out?
The heart can pump out what it RECIEVES BACK.
172
What position makes the venous return to heart more difficult?
Upright posture
173
What are the three mechanisms that assist venous return?
1. One-way valves ; allows for one way flow of blood
2. Muscle pump
3. Respiratory pump - occurs when one is doing heavy exercise, more air moves in and out of lungs = change in THORACIC PRESSURE → help cycle blood back to heart
174
Which mechanism that assists venous return is damaged when varicose veins appears?
One-way valves
175
Explain how does muscle pump work?
When a skeletal m. contracts, the veins that it surround pushes blood to go up through the open valve that will lead to the heart. Muscle pump also consists of a closed valve that doesn't allow the backflow of blood
176
Why should we not keep our knees locked?
May inhibit venous return to our heart from our lower limbs. Contractile activity does not occur with knees locked, thus keeping the blood being pooled and not returning to the heart, causing one to collapse.
177
What are the 5 variables involved that alters heart function/peripheral circulatory adaptations?
– Heart rate
– Stroke volume
– Cardiac output
– Blood pressure
– a-vO2diff
178
What stimulates heart rate (HR) to go from rest to maximal intensity of exercise, in other words, control it? What does it target?
Neural control/stimulation/ Nervous system
* SA node (pacemaker of the heart)
179
What type of increase is HR from rest to max?
Linear increase
180
What is the initial control of HR at rest?
(PNS) Parasympathetic nervous system
181
(a) What allows HR to increase from rest to 100 bpm?
(b) What occurs at 100 bpm?
(a) Through the gradual withdrawal of PNS activity
(b) The full withdrawal of PNS activity
182
(a) What allows HR to increase from 100 bpm and beyond?
(b) If heart rate was to increase from 100 bpm to 105 bpm, what is being activated?
(c) How much is its activation?
(d) As exercise intensity increases, was it expected of the degree of activation?
(e) At maximal intensity of exercise, what occurs for the activation?
(a) Increased/Gradual increase SNS activity
(b) SNS activity
(c) Little activation
(d) SNS activity will start to increase
(e) FULL activation of SNS at maximal intensity exercise
183
How much does SV increase up to from rest? What type of increase is this? What occurs after?
Rest to 60% VO2max (Linear increase) → plateau
184
What are the two causes that changes the SV during acute exercises?
↑SV = ↑EDV - ↓ESV
1. Increased EDV
- LVEDD (L ventricle end diastolic diameter = size of L ventricle)
- Increased venous return! - redistribution of blood to the the heart
2. Decreased ESV
- Increase in contractility! (due to sympathetic nervous system = forceful contraction)
- (Frank-starling mechanism) - chamber is filled with the preload of blood in L ventricle, causing it to stretch, sending signals to the connective tissue, so that when the heart contracts it causes a forceful contraction = more blood gets pumped out
185
When and why does plateau occur in SV during acute exercises?
Plateau at 60% VO2max
Why?
- Heart size (LVEED): fixed chamber size in L ventricle
- Blood volume: limited amount of blood than can be distributed/back to heart
186
What regulates cardiac output from rest to 60% VO2max? What type of increase is this?
An increase in HR and SV
- Linear increase
187
From 60%VO2max to max, what regulates cardiac output? What type of increase it this?
Increase in HR ONLY
- Linear increase
188
What is blood pressure referred to as and what is it? What is the formula for BP?
Systolic BP
BP is the resistance to blood flow
BP = Q x TPR
189
What is TPR?
TPR - Total Peripheral Resistance
- How much vasodilation is the arteries getting?
190
What is the cardiac output at rest and at maximal exercise intensity?
Rest: 5 L/min
Max: 25 L/min
191
As exercise intensity increases, consider the following:
(a) Does more blood get pushed through the circulatory system?
(b) What happens to systolic BP?
(a) Yes
(b) Increases
192
Describe blood pressure as one goes from a resting state to an exercising state.
- Blood pressure is the resistance to blood flow.
- At a resting state, blood pressure is typically low, since cardiac output is 5 L/minute.
- But as exercise intensity increases, there is a significant increase of cardiac output to 25 L/min, and blood vessels will start to dilate, delivering blood to active muscle, due to local factors but its degree is not as significant to cardiac output since it is just a slight decrease in TPR, thus resulting in systolic blood pressure also increasing.
193
During exercise, why is systolic BP much higher in the arms than the lower limbs?
There is smaller muscle groups and a smaller vasculature system in the arms versus the legs.
194
What does a-vO2 diff stand for? What is the units used?
a: arterial
v: venous
O2: oxygen that is in the arterials and venous
Units - mL of O2/100mL of blood
195
At sea level, what is the O2 concentration for arterials? What is this based on?
20 mL of O2/100mL of blood
- Based on hemoglobin concentration
196
What is the O2 concentration for venous side going to R atria at rest and at max. intensity? Why?
Rest (little activity): 15 mL of O2/100mL of blood
~ Tissues/muscles do NOT need much to extract O2 from arterial blood, thus lots of O2 in venous blood when going back to heart
Max: 5 mL of O2/100mL of blood
~ Tissues/muscles extract a greater amount of O2 from blood
197
What is the a-vO2 diff at rest and at max. exercise intensity? In other words, how much O2 did the venous extract from the arterials in these conditions? Why do we extract that much amount at max.?
Rest: 20 - 15 = 5 mL of O2/100 mL of blood
Max: 20 - 5 = 15 mL of O2/100 mL of blood
~ a-vO2 diff. is much larger during max. so that the large amount O2 that is being extracted can support a greater aerobic production of ATP
198
As exercise starts, where does the signal start at? What will it do?
Starts at the higher brain center
- Activates the appropriate HR, BP, and VENTILATORY RESPONSE for the amount of muscle mass that is activated at the onset of exercise
199
What regulates BP? Where are they located?
Baroreceptors: regulate BP
Located throughout the heart and carotid bodies
200
What is the difference between respiration and ventilation?
Respiration: oxidation of fuel occurring at the level of the cell (substrate-level phosphorylation)
- EX: RER - O2 is used to combust CHO and fat and produce CO2
Ventilation: Movement of gases across the lung and diffusion of CO2 in blood and tissue
201
Where does gas excahnge occur?
In the alveoli and the tissues
202
What is air made up of? What is the gas that makes up the most of it?
100% Air = 79.04% N2 + 20.93% O2 + 0.03% CO2
- Nitrogen makes up the bulk of it!
203
What are atmospheric gases referred to? What is the unit used?
Partial pressures
Units: mmHg
204
What is the standard atmospheric pressure?
760mmHg
205
How will gases moves?
Gases will always move from an area of HIGH partial pressure to LOW partial pressure
206
What is the partial pressure for the following atmospheric gases:
(a) PN2
(b) PO2
(c) PCO2
(a) PN2 = 600.7 mmHg
(b) PO2 = 159.1 mmHg
(c) PCO2 = 0.2 mmHg
207
When air is being breathed in through our nose and mouth, what else is being added? What other atmospheric gas should be considered?
Humidity will also be added as we breathe through out nose and mouth
- Water pressure also has to be counted that gets into the alveoli
208
In the alveoli, where does O2 go vs. where CO2 go? Why?
O2 - goes to the blood (capillaries)
CO2 - goes to lung (alveoli)
Why? They go from HIGH partial pressure to LOW partial pressure
209
(OPTIONAL) Memorize the value (including units) of PO2 & PCO2 in…
1. alveoli
2. arteries entering tissue (systemic) capillaries
3. veins leaving tissue capillaries
Alveoli
* PO2: 105 mmHg
* PCO2: 40 mmHg
Arteries entering tissue (systemic) capillaries
* PO2: 100 mmHg
* PCO2: 40 mmHg
Veins leaving tissue capillaries
* PO2: 40 mmHg
* PCO2: 46 mmHg
210
Are pulmonary arteries filled with oxygenated blood or deoxygenated blood? What about pulmonary veins?
- Pulmonary arteries are filled with deoxygenated blood, which is the only time we see PCO2 (46mmHg) in the pulmonary versus the PO2 (40mmHg).
- The pulmonary veins on the other hand will carry oxygenated blood back to the heart with the PO2 at 100mmHg and PCO2 at 40 mmHg.
211
When is the only time we see PCO2 being greater than PO2?
Pulmonary artery from the R ventricle that is going to the lungs
212
Compare the PO2 in an active muscle vs. inactive muscle
Active muscle:
PO2 in the muscle will go down as it will use the O2 in the mitochondria to produce ATP aerobically
~ This reduction of PO2 is the driving force for O2 to come out of the blood and into the muscle
Inactive Muscle:
PO2 is high because there is not much need of diffusion of O2 from blood going to the muscle
213
In the venous side what gas is being extracted and what is being produced?
- O2 extracted
- CO2 produced
214
What are the two ways that oxygen can be transported in blood?
1. (PREDOMINANTLY) >98% bound to hemoglobin (Hb) in red
2. <2% dissolved in plasma
- gases don't travel well in liquid
215
What is oxyhemoglobin and deoxyhemoglobin?
Hemoglobin = protein
– O2 + Hb: oxyhemoglobin
– Hb alone: deoxyhemoglobin
216
How many hemoglobin is in a male and female?
Male: 15g Hb in every 100 mL of blood
Female: 12.5g Hb in every 100 mL of blood
217
How many mL of O2 is bound to one hemoglobin?
1.34 mL of O2 bound to 1 hemoglobin
218
What are two characteristics of hemoglobin?
1. Bind to oxygen (affinity) at a really high capacity when blood is in the alveoli to have high saturation in Hb in order to deliver adequate amount of O2 to the tissues
2. However, at some point, O2 should be released/dissociate by Hb
219
In the oxygen-hemoglobin dissociation curve, where does high affinity of O2 and Hb occur and where does significant offloading of O2 from hemoglobin occur in the body and at what PO2?
High affinity: At the alveoli
Significant offloading: At the skeletal muscle
-PO2 is lower at 40 and 50 mmHg
220
What is the Bohr effect? What characteristic is beneficial during exercise.
Changes in tissue pH and temperature alters the oxygen-hemoglobin dissociation curve
- Higher body temp. and acidic pH is beneficial for exercise as it cause a greater and easier unloading of O2 at skeletal m.
221
Describe the effect temperature and pH each have on the oxyhemoglobin dissociation curve. Focus when pH becomes acidic and body temp. increases!
— Effect of Temperature on Oxygen Transport
* Curve shifts to the right (higher body temp.) ! = less affinity (bond) for O2 = GREATER unloading of O2
* Curve shifts to the left (lower body temp.) = more affinity (bond) for O2 = LESSER unloading of O2
— Effect of pH on Oxygen Transport
* Curve shifts to the right (Less pH) ! = less affinity (bond) for O2 = GREATER unloading of O2
* Curve shifts to the left (High pH) = more affinity (bond) for O2 = LESSER unloading of O2
222
What are the three ways that carbon dioxide can transport (away from tissue and to the lungs) and what are the percentages?
1. Bicarbonate (MAJORITY - 60-70%)
2. Dissolved in plasma (7-10%)
3. Bound to Hb (carbaminohemoglobin); (20-33%)
223
What is the percentage of bicarbonate used to transport CO2 in blood to lungs?
Transports 60 to 70% of CO2 in blood to lungs
224
Describe what, where and how carbonic acid (H2CO3) is formed?
CO2 + water (from RBC) form carbonic acid (H2CO3)
– Occurs in red blood cells
– Catalyzed by carbonic anhydrase (accelerates this reaction)
225
What occurs when carbonic acid (H2CO3) dissociates? What happens at the lungs after?
Carbonic acid dissociates into bicarbonate
CO2 + H2O→ H2CO3 → HCO3- + H+
– H+ binds to Hb (buffer), triggers Bohr effect = better offloading
– Bicarbonate ion diffuses from red blood cells into plasma
226
(OPTIONAL) Memorize the Carbonic Acid Reaction
CO2 + H2O (w/carbonic anhydrase →) H2CO3 → HCO3- + H+
227
(a) What is the percentage of dissolved CO2 used to transport CO2 in blood to lungs? Why
(b) When can we see a large amount of CO2 being dissolved in plasma? Why?
(a) 7 to 10% of CO2 dissolved in plasma
- Liquid is not the best way to transport gases
(b) When tissue PCO2 is high = to get more PCO2 in plasma, so when PCO2 low (in lungs), CO2 comes out of solution, diffuses out into alveoli
228
(a) What is the percentage of carbaminohemoglobin used to transport CO2 in blood to lungs?
(b) How is CO2 able to bind Hb with O2 there? Do they compete? What binds to what part?
(c) What can affect the interaction between CO2 and Hb?
(d) What type of hemoglobin binds to CO2 easier?
(a) 20 to 33% of CO2 transported bound to Hb
(b) Does not compete with O2-Hb binding
– O2 binds to heme (iron component) portion of Hb
– CO2 binds to protein (-globin) portion of Hb
(c) PCO2 affect CO2-Hb binding
– ↑ PCO2 → easier CO2-Hb binding
– ↓ PCO2 → easier CO2-Hb dissociation
(d) Deoxyhemoglobin binds CO2 easier versus oxyhemoglobin
229
What is the major driving force for O2 to move out of the arterials?
Partial pressure
230
At PO2 being 3-4mmHg, hemoglobin has off loaded a great amt. of O2, but what occurs during myoglobin? What does this say about the affinity for myoglobin?
In the skeletal m., the mitochondria has a PO2 of 3-4mmHg.
- Myoglobin will continue to hang onto the O2 until it gets to mitochondrial reticulum to release it
- Myoglobin has a much higher binding affinity until it is at close proximity with the mitochondria
231
(a) What causes the pre-exercise ventilation elevation?
(b) What is ventilation proportional to in exercise?
(a) Ventilation at the onset of exercise is from the pre-anticipatory response
(b) Ventilation is proportional to the amt. of muscle mass that's active
232
What is the 2 step approach of ventilation during exercise?
1. During onset of exercise, an initial ventilatory rate is set by the higher brain centers
2. Feedback from other areas of body that help fine-tune the ventilatory rate
233
Describe the pulmonary ventilation regulation process.
1. High brain center - initial signal for ventilation to occur (sets HR, BP, & ventilation); proportional to muscle mass that is activated
2. Ventilatory control centers (medulla oblongata) - regulates initial ventilatory rate
- Peripheral chemoreceptors + central chemoreceptors and mechanoreceptors/muscles (from skeletal m.) help fine tune
3. Ventilatory muscles - external and internal intercostals, obliques, diaphragm
234
Where is the initial signal for ventilation to occur?
Higher brain center
235
What are peripheral chemoreceptors sensitive to and where are they located?
(Peripheral) Chemoreceptors: Sensitive to blood PO2, PCO2, H+
Located in: Aortic bodies and carotid bodies
236
What do central chemoreceptors detect?
Chemoreceptors: detect [CO2]
237
Why is ventilation NOT a limiting factor for VO2max?
Large amount of CO2 and O2 can move in and out of the alveoli and blood due to the LARGE SA of the alveoli
- Ventilation muscles account for 10% of VO2, 15% of Q during heavy exercise
- Ventilation muscles are fatigue resistant
- CAN be a limiting factor if one has lung disease or lung cancer
238
How can blood help regulate pH AKA acid-base balance? What is a good buffer?
With the use of the of buffer it can drive metabolic acid away from skeletal m. ; aka acid-base balance system
- Metabolic processes produce H+ → ↓pH
- If ion is free in solution it will have an affect in pH... however, if ion is bound to a buffer, it will NOT have an effect in pH of solution
- H+ + buffer → H-buffer
- Blood is a good buffer
239
What is the first line of defense against pH shift during exercise?
Buffers
240
In the muscle, if acid is produced, what are the 3 buffers that can be used and what is the one that is being primarily used? What will these do once bound to the acid?
Phosphate buffer (PRIMARILY), cell proteins, and bicarbonate buffers
- Buffer will give acid/ion away to blood
241
What are the 3 buffers within the blood and what is the buffer that is being primarily used?
Bicarbonate buffer (PRIMARILY), blood proteins, hemoglobin
242
(a) Give an example for passive recovery and active recovery.
(b) What happens to blood lactate concentration after exercise if one was to do passive recovery or static recovery? Why?
(c) Between passive recovery and active recovery, which is more efficient for lactate clearance post-exercise.
(a) Passive recovery - Sit
Active recovery - Walk at 30% VO2max or pool
(b) Blood lactate concentration remains HIGH post-exercise for people that did PASSIVE recovery. However, people that did ACTIVE recovery were able increase rate of lactate clearance by maintaining blood flow to active muscles (blood will then go to the liver)
(c) Active recovery
243
What are 2 ways that lactate can be used?
- 60% of lactate gets taken up by the liver, where it will then be converted to glycogen
- Lactate can also be taken by adjacent muscle cells where it will be oxidized and produce ATP aerobically
244
(a) Does being on land versus on water during active recovery change the rate of lactate clearance post-exercise?
(b) Why do some athletes prefer to be in water post-exercise, in other words, why did athletes perceive that they have full lactate clearance when they went to the water post-exercise?
(a) No, blood lactate clearance is still the same, however, some athletes feel better with water active recovery post-exercise
(b) - No bodyweight is involved when in the pool
- Hydrostatic pressure, due to legs being in the water, may have helped with venous return
