ex phys test 3

systole

contraction phase "pumping"

diastole

relaxation phase "filling"

P wave

atrial depolarization (contraction)

QRS complex

ventricular depolarization (contraction) and atrial repolarization (relaxation)

T wave

ventricular repolarization (relaxation)

increases with work, later moderate rise due to SV limit

Q changes with incremental exercise

increases with work until max plateau

HR changes with incremental exercise

increases with work until 40-60% max

SV changes with incremental exercise

SBP changes with incremental exercise

increases with work

DBP changes with incremental exercise

generally unchanged due to vasodilation from exercise

poiseuille's law of flow

factors affecting resistance

the effects of radius, viscosity, etc. on blood flow

vessel length -- increase leads to increased resistance

blood viscosity -- increase leads to increased resistance

vessel radius -- increase leads to decreased resistance

autonomic nervous system effects on HR

- increased parasympathetic (vagal) activity; SA node inhibition - decreased HR

- increased sympathetic activity; SA node stimulation - increased HR

body temperature effects on HR

- low body temp - decreased HR

- high body temp - increased HR

1st auscultation

atrioventricular (AV) valves close close together; left: bicuspid (mitral): right tricuspid, lub sound

2nd auscultation

semilunar valves close together; left: aortic; right: pulmonic, dub sound

Q is maintained

Q output changes during prolonged exercise

EDV (end diastolic volume)

amount of blood at completion of the filling phase

ESV (end systolic volume)

amount of blood left behind after the pumping phase

reflects the amount ejected

the difference of EDV and ESV ..

preload effects of SV

reflects EDV; more blood filling the left ventricle = more SV; high - high SV; low - low SV; determined by venous return

vasoconstriction

skeletal muscle pump

respiratory pump

factors promoting venous return

afterload effects on SV

reflects mean arterial pressure (MAP) of aorta; high pressure in vessels acts as a "wall" blocking SV; high - low SV; low - high SV

LV

large A

arterioles

precapillary sphincters

capillaries

venules

large veins

general pressure differences among blood vessels (first is largest, last is smallest)

aorta and arteries

highest pressures

venules and veins

pressure is extremely low

left ventricle is the thickest chamber and is the only one that can develop with exercise. right atrium and left atrium are thinner and right ventricle is a little thicker to pump to lungs

structural differences among the 4 heart chambers

ceiling of RA

SA node

floor of RA

AV node

septum

bundle of His

branch upwards from bb into the ventricular myocardium

purkinje fibers

split from the bundle of His with the septum

right and left bundle branches

flow = pressure / resistance

formula for flow of liquid through a vessel

vessel radius

has the biggest influence; affects flow to the 4th power

general mechanism for redistribution of blood flow

increased to working skeletal muscle due to vasodilation; reduced to less active organs by vasoconstriction; both self-regulate blood flow based on demand (autoregulation)

systolic

peak pressure when the heart contracts (120)

diastolic

represents the lowest pressure when the heart relaxes and fills (80)

increased Q

increased O2 extraction at muscle (higher arterio-venous blood oxygen difference (a-vO2 diff))

redistribution of blood flow

sources of improvement for VO2 max

HR max 0%

SV max 50% (increased preload and contractility and decreased afterload)

a-vO2 max 50% (increased muscle blood flow, capillary density, mitochondrial number)

increase in VO2 max based on initial fitness level and training intensity

VO2 max can decrease by 20% if training stops

early loss - stroke volume (pumps less blood per beat)

later loss - muscle mass and oxygen extraction ability (a-vO2 difference)

heart rate may increase slightly to compensate but cannot fully offset losses

fitness adaptations are not permanent and require consistent training

order of results related to detraining and losses of VO2 max

AT (anaerobic threshold)

refers to the lactate and ventilatory threshold phenomena; exercise intensity at which lactate and/or ventilation rise exponentially rather than predictably;

exercise prescription to increase AT

high intensity exercise just below AT; interval training (frequency is moderate due to injury risk)

expected increase in AT

increases regardless of population; more trainable than VO2 max

oxygen -- diffuses into blood; binds to hemoglobin

carbon dioxide -- diffuses into alveoli; removed by exhalation

diffusion -- passive process; requires no ATP

gas exchange occurs because of pressure gradients (not active transport)

conversion of CO2 into bicarbonate (temporary conversion and facilitates enhanced transport)

elevated PCO2 causes CO2 to combine with H2O

catalyzed by carbonic anhydrase found in RBCs

basic events at the alveolus with regards to gas exchange

beginners, older adults, cardiac pts

usually exercise below AT because it is safer, easier to maintain and cause less fatigue

athletes and well trained individuals

train at or above AT to improve endurance and performance

converted to bicarbonate in the blood (70%)

combined with hemoglobin in blood (20%)

dissolved in blood (10%)

percentages of CO2 transport

android/male pattern - high risk (apple shape)

gynoid/female pattern - moderate risk (pear shape)

anthropometric obesity types and associated risks

waist-hip ratio

divide waist circumference by hip circumference; based on body shape and location of excess fat (males > 0.95 = increased risk; females > 0.8 = increased risk)

BMI

height-to-weight comparison; doesn't reflect body fat %; low risk = 18.5 - 25; overweight = 25-29; obese = 30+

body density

used to estimate body fat percentage from equations based on age, gender, and/or race

underwater weighing

involves weighing submerged body; lower density of fat causes buoyancy compared to lean tissue

BIA

measures body composition using a small electrical current; estimates: body fat %, muscle mass, water content; quick, inexpensive and easy to use

DEXA

uses low-dose Xrays to measure body fat, lean mass, bone density; often considered a "gold standard" body composition test

skinfold techniques

involves measuring thickness of subcutaneous fat with a caliper device (high density = low fat and high lean; low density = low lean and high fat)

effects of ventilation after training

lower for trained individuals when at the same work rate as untrained; VT occurs at a higher work rate for trained individuals comapred to untrained

classical glycogen loading plans

prolonged intense exercise to deplete glycogen stores on first day; normal training and 50% carbs for 3 days; no training and 90% carbs for 3 days

Modified Glycogen Loading plans

3+ days of tapering long to medium workouts and 50% carb diet; 2 days of short workouts and 70% carb diet; 1 day of rest and 70% carb diet

both are similar and modified is best

effectiveness and ease of use for glycogen loading plans

limiting factors of the pulmonary system on aerobic performance

at submaximal exercise: absolutely not a limiting factor

at maximal exercise: generally not a limiting factor; may be limiting in elite endurance athletes due to ventilation:perfusion ratio mismatch

mitochondrial number response to endurance training

increase

oxidative enzymes response to endurance training

increase

NADH shuttling system response to endurance training

increased

capillary density response to endurance training

increase

B-oxidation enxymes response to endurance training

increase

FFA oxidation response to endurance training

increase

O2 deficit response to endurance training

decreased

lactate production response to endurance training

decreased

PC depletion response to endurance training

decreased

Reasons for diffusion of gases

gas moves from high-low partial pressure; btw lung and blood; btw blood and tissue

partial pressure of gases

total air pressure equals sum of each individual gas (N2, O2, CO2) pressure; designations: PO2 (greater in alveoli) and PCO2 (greater in blood)

0 mmHg

pressure at RA

100 mmHg

pressure at LV

RA->tricuspid valve->RV->pulmonary arteries->capillary beds of lungs->pulmonary veins->LA->bicuspid valve->LV->aorta->systemic arteries->capillary beds of tissues ->systemic veins->superior/inferior vena cava

circuit of blood flow

blood volume

total peripheral resistance

cardiac output

factors that influence blood pressure

blood volume

more blood = high pressure

athlete - increased BV (O2 transport)

sedentary - Na intake increase H2O retention and blood volume, reducing salt or using diuretics can lower pressure

total peripheral resistance

how open/closed vessels are; constricted vessels: higher resistance, higher pressure; dilated vessels: lower resistance, lower pressure; athlete: training signals nervous system to relax smooth muscle around vessels, leading to dilation; sedentary: pharmaceuticals can relax smooth muscle and cause vasodilation

cardiac output

amount of blood ejected from the heart per minute (HRxSV); higher Q = more blood pushed against vessel walls, higher pressure

HRxSV

Q=

EDV-ESV

SV=

DBP+1/3(PP)

MAP=

SBP-DBP

PP=

increased cardiac output

increased O2 extraction at muscle

redistribution of blood flow

3 methods of increasing oxygen delivery

increased cardiac output

due to increased HR or SV

increased O2 exctraction at muscle

leads to higher arterio-venous blood oxygen difference (a-vO2 diff)

Redistribution of blood flow

increased to working skeletal muscle due to vasodilation; reduced to less active organs by vasoconstriction; both self-regulate blood flow based on demand

Q-maintained

HR- gradual increase due to increased body temp and dehydration

SV-gradual decrease due to reduction of plasma volume from sweating

circulatory responses to prolonged exercise

increased parasympathetic (vagal) activty (SA node inhibition - decreased HR)

increased sympathetic activity (SA node stimulation - increased HR)

autonomic nervous system regulation of HR

inspiration

diaphragm contracts/lowers, reducing intrapulmonary pressure below 760 mmHg; flow of air into lungs to create equilibrium

expiration

diaphragm relaxes/rises, increasing intrapulmonary pressure above 760 mmHg; flow of air out of lungs to lower pressure environment

refers to the combined LT and VT phenomena - exercise intensity at which lactate and/or ventilation rise exponentially rather than predictably

Anaerobic threshold (AT)

blood lactate testing, ventilatory threshold, talk test

measurement of AT

blood lactate testing

blood samples are taken during exercise; measures lactate levels directly; AT is identified when lactate rises sharply

ventilatory threshold

measures breathing and gas exchange; AT occurs when ventilation increases disproportionately; common during Vo2 max tests

talk test

simple field method: below AT = can speak comfortably; Near/above AT = talking becomes difficult

conducting zone

functions: conduct, warm, humidify and filter air; components: trachea, bronchial tree, bronchioles

respiratory zone

function: exchange gases between air and blood; components: respiratory bronchioles; alveolar sacs