Cardiorespiratory System Flashcards
Blood is separated into
55% plasma
<1% leukocytes
45%platelets and erythrocytes
Blood is responsible for transporting
Oxygen, nutrients, metabolic byproducts.
Normal blood pH range and influential factors
7.4 normal
Between 6.9 and 7.5
Exercise, stress, disease
MusclenpH range
6.63 - 7.10
pH is regulated by buffers such as
Bicarbonate, ventilation, kidney function
O2 transport quantities
Dissolved O2 is .3 ml O2 per 100ml of blood or 2%.
Via hemoglobin:
Each gram of hemoglobin can carry 1.39 ml of O2
Healthy blood carries 15 grams of hemoglobin per 100 ml.
Therefore blood carries 20.8 ml O2/100ml blood
Average body carries 5 liters blood, about 7% of body weight
Partial pressure
Pressure exerted by one gas in a mixture of gasses. Calculated at the product of total pressure of a gas mixture and the % concentration of the specific gas.
Normal atmospheric pressure = 760mmHg
O2 percent concentration in the atmosphere is 20.93%. It partial pressure 159mmHg (760x[20.93/100])
O2-hemoglobin dissociation curve
The relationship of O2 and O2 saturation is sigmoidal due to cooperative binding. The O2 molecule binding to hemoglobin increases hemoglobin affinity for O2
Saturation begin to plateau at 60 mmHg. 90%
An increase from 60 mmHg to 100 mmHg -> 99% hemoglobin saturation with O2
Factors affecting oxyhemoglobin curve
Decreased body temp- shifts left
Inc body temp- shirts right
Low pH (acidity) - shifts right High pH (alkalosis) - shifts left
O2 is released from hemoglobin at a higher partial pressure so it can be used by working muscles.
The heart is copses of
Cardiac muscle
Mononucleated
4 chambers
Under involuntary neural control
SA node - primary intrinsic pacemaker generating electrical impulse across the atrium .08m/s. to the
AV node - spreads the impulse through the R&L bundle branches into the purkinje system, fibers that surround the ventricles. -> ventricular contraction.
Electrocardiogram
P wave - atrial depolarization. The impulse travels from the mSA node to the AV node
QRS wave - ventricular depolarization. The impulse continues from the AV node tot he Purkinje fibers throughout the ventricles.
T wave - repolarization (electrical recovery) of the ventricles.
Arteries pressure system
100 mmHg in aorta to 60 mmHg in arterioles
Veins pressure and structure
Low pressure, one way valves, smooth muscle bands facilitated by muscular contraction.
Total peripheral resistance
Resistance of the entire circulation
Affected by vessel constriction or dilation from exercise , sympathetic nervous system, metabolism, environmental stressors,
Cardiac cycle
From the start of one heart beat to the start of another.
Includes the diastolic pressure exerted on the arterial walls when the heart is filing with blood and no blood is being ejected.
The systolic BP exerted against the arterial walls during ventricular contraction
Rate-pressure product
RPP = SBP x HR
Describes the work of the heart and provides an estimate of myocardial o2 uptake. Also referred to as double product.
Mean arterial pressure
Ther mean BP throughout the cardiac cycle
MAP = DBP + [.333 x (SBP - DBP)]
Cardiac output.
The amount of blood pumped by the heart in one min.
Q = SV x HR
Stroke volume
The amount of blood ejected per HB
SV = EDV - ESV
Frank-starling principle
Based on the length tension relationship
The more more the left ventricle is stretched the more forceful the contraction and greater the volume.
An increase in preload EDV is directly influenced by the feart volume and venous return
Respiratory structure
Nasal cavities for warming moisturizing purifying -> trachea -> bronchi -> bronchioles (23 generations) -> alveoli
Respiratory muscles at est
Rest
Inhalation - diaphragm & external intercostal contract. Lung space incrrases, pressure decreases, air enters.
Exhalation - passive relaxation of diaphragm and ext. int. decrease volume & increases pressure. .
Respiratory muscles at exercises
Inhalation - diaphragm, external intercostals, SCM, scalenes, Pec minor and major
Exhalation - internal intercostals, abs, facilitate quicker removal.
Lung volume
Sprirometer
Gas exchange - diffusion
Occurs cm between the capillaries and the alveoli.
The movement of gas such ad O2 & CO2 across cel membranes
Occurs when a concentration gradient of gas is greater on one side.
Partial pressures from gas exchange.
Inspired PO2 159mmHg At alveoli PO2 100 mmHg Venous blood PO2 40 mmHg, PCO2 46 mmHg. Arterial blood PO2 100 mmHg, PCO2 30 mmHg. Muscle PO2 40 mmHg, PCO2 46 mmHg
Oxygen uptake / Oxygen consumption
Measured a the mouth using a metabolic cart.
The ability of the heart and circulatory system to transport O2 via the blood to the tissues and the ability of the tissues to extract O2.
The Fick equation:
VO2 = Q x a-vO2
= (HR x SV) x a-vO2
= ((HR) x (EDV-ESV) x a-vO2
Activity levels and O2 extraction
Arterial side - 20ml O2/100ml blood
Venous side:
Rest - 14 ml O2/100ml blood
Moderate -10 ml O2/100ml blood
High - 4 ml O2/100ml blood
Extraction:
6, 10, 16
Maximal Oxygen Consumption (VO2 max)
The highest amount of O2 that can be used at a cellular level.
Correlates with the degree of physical conditioning and measures cardiovascular fitness.
Typical resting VO2 3.5 ml • kg-1 • min-1
Possible VO2max 80 ml • kg-1 • min-1
Bioenergetics
The conversion of food, large carbohydrates, protein, and fat molecules into biologically usable forms of energy
Catabolic
The break down of large molecules to small molecules such as carbohydrates to glucose causing a release of energy.
Anabolic
The synthesis of larger molecules from smaller one by using the energy released from catabolic reactions.
Example, the formation of protein from amino acid
Metabolism
The constant state of anabolism and catabolism
Adenosine triphosphate (ATP)
An intermediate molecule that releases energy from catabolic reaction. The energy is then use to drive anabolic reactions
Required for muscle activity and growth
ATP make up
Adenine, a nitrogen-containing base
Ribose, a five carbon sugar
Three phosphate groups. ATP - high energy
Two phosphate groups ADP
one phosphate group AMPo
Three energy systems
Phosphates system - anearobic process.
Glycolysis - fast and slow glycolysis, Borge anearobic
Oxidative - aerobic.
Phosphagen system
Primary source of ATP for short term high I intensity activities
Active at start of all types of exercise.
The energy for the muscular activity
relies on chemical reactions of phosphagens ATP and creatine phosphate.
Myosin ATPase increases the rate of break down of ATP to form ADP and inorganic phosphate Pi -> energy release / catabolic reaction.
Creatine kinase increases the rate of synthesis of ATP from creatine phosphate & ADP by supplying a phosphate to form ATP/
Anabolice reaction.
Type II fast twitch fibers contain greater concentrations of phosphagens.
Exercise increases break down of ATP> increase in ADP>elevated creatine kinase activity> regulating the breakdown if creatine phosphate> formation of ATP .
Discontinuation if exercise or continuation is exercise at a low enough intensity allows transition to glycolysis or oxidative system and reduction of creatine kinase activity.
Glycolysis
The breakdown of carbohydrates, either glycogen stores in the muscle or glucose delivered in the blood, to produce ATP.
Supplements the phosphagen system initially, then becomes the primary source for high-intensity muscular activity they lasts up to about 2 mins (600-800m)
Enzymes in the sarcoplasm are involved in glycolysis.
Fast glycolysis - anearobic glycolysis. The end product piruvate is converted to lactate providing energy (ATP) at a faster rate.
Glucose+2Pi+2ADP->2lactate+2ATP+H2O
Slow glycolysis - aerobic
Glycolysis. Piruvate is transported to the mitochondria for energy production through the oxidative sytem. Another biproduct is reduced nicotinamide adenine dinucleotide - 2NADH
Glucose+2P+2ADP+2NADH+->2pyruvate+2ATP+2NADH+2H2O
Energy yield of glycolysis
2 molecules of ATP from 2 molecule of glucose.
Glycogen ( the stored form of glucose) -> 3 ATPs because ohosphorylating which requires 1 ATP is bypassed.
Glycolysis regulation
Stimulated by ADP, P1, ammonia and a slight decrease in pH, and strongly stimulated by AMP.
Inhibited by markedly lowered pH during periods of inadequate O2 supply and increased ATP, creatine phosphate, citrate, and free fatty acidstgat are usually present at rest.
Rate limiting step - PFK is the primary regulator of the rate of glycolysis.
Lactic acid and blood lactate
Fast glycolysis during periods of reduced O2 availability results in lactate which can be converted to lactic acid.
Fatigue more likely from decreased pH from many sources of acid including the intermediates of glycolysis.
Decreased pH inhibits calcium binding to troponin, inhibiting actin-myosin cross bridge formation. Inhibits Enzo activity of the cell’s energy systems.
Lactate - an energy substrate in type I and cardiac muscle fibers. Used in gluconeogenesis. It’s clearance in the blood indicates a persons ability to recover. Cleared by oxidation within the muscle fiber, blood transport, to other muscle fibers or to the love to be converted to glucose - the cori cycle
Blood lactate returns to normal within an hour after activity.
Livht activity removes it quicker
Normal .5-2.2 mail/L
Peak occurs at 5mins post
Exercises
Lactate threshold
Increase reliance on anaerobic mechanisms. Begins at 50-60% of Max VO2 in untrained subjects . 70-80% in trained subjects
Onset of blood lactate accumulation OBLA @ ~ 4 mmol/L
Blood lactate near 4 mmol/L
Intermediate or large motor units are recruited string increasing exercise intensity - type II
LT or OBLA occurs at a higher intensity of exercise in a trained person due to increased mitochondria.which allows for greater production of ATP
Through aerobic production.
Oxidative system
Primary source of ATP at rest, & during aerobic activities.
At rest, 70% from fats, 30% from carbohydrates.
High intensity aerobic, almost 100% from carbohydrates.
Prolonged Aerobics shifts to fats and eventually proteins
When Is protein metabolized
Long term starvation
Exercise greater than 90mins
Glucose and glycogen metabolism
Begins with glycolysis. The end product , pyruvate, is transported tot eh mitochondria . Converted to acetylCoA. Enters the Krebs cycle for further ATP production.
Gay oxidation
Triglycerides stored in fat cells are broken down as hormone sensitive lipase. Free fatty acids are released, enter the mitochondria and undergo beta oxidation. Acetyl CoA is formed, enters the Krebs cycle. The hydrogen atoms are carried by nadh & fadh to the etc
Protein oxidation
Broken down to amino acids, converted to glucose by gluconeogenesis, pyruvate…->Krebs cycle
3-18% of energy requirements in prolonged exercise.
Waste products are urea and ammonia. Eliminated via urine
Oxidative system regulation in the Krebs cycle.
The conversion of isocitrate to alpha-ketoglutarate that is controlled by isocitrate dehydrogenase.
System. Rate of ATP prod . Capacity
Phosphagen. 1. 5. Fast glycolysis. 2. 4. Slow glycolysis. 3. 3. Oxidation of carbohydrate. 4. 2. Oxidation of fat and protein. 5. 1.
Duration of event. Intensity. Energy system
1-6s. Very intense. Phosphagen
6-30s. Intense. Phosphagen & fast glycolysis.
30s-2m. Heavy. Fast glycolysis
2-3m. Moderate. Fast glycolysis & oxidative system
>3m. Light. Oxidative system
Fatigue is frequently associated with the depletion of
Phosphagens and glycogen
Patterns of phosphagen depletion and repletion
High intensity anearobic exercise. Creatine phosphate by 50-70% in 5-30 s Muscle ATP not more than 60% Complete resynthesis of ATP in 3-5m Creatine phosphate in 8mins
Glycogen depletion and depletion rates
300-400 g stored in muscle
70-100 g in the liver
Resting storage can be influenced by all training and diet.
Muscle glycogen for mod-high intensity exercise
Liver glycogen for low intensity exercise
Depletion is variant. Depletion is optimal if .7-3G of carbs per kilo of body weight every 2 hours. Complete depletion in ~ 24 hours
Oxygen deficit
The anearobic contributioon to the total energy cost of exercise
Oxygen debt or EPOC (excess post exercise oxygen consumption
Post exercise oxygen uptake.
