HK 368- Exam II

Which of the following would be considered an excellent VO2 maximum for a college-aged man? A) >60 ml/kg/min B) 50 ml/kg/min C) 30 ml/kg/min D) 20 ml/kg/min

A) >60 ml/kg/min

Increasing end diastolic volume would result in an increase in: (1 point) A) preload B) end systolic volume C) a-vO2 difference D) arterial oxygen content

A) preload

While exercising in a hot, dry environment the predominate means of cooling the body is (assume no influence of clothing or wind velocity)? A) sweating B) radiation C) convection D) evaporation

A) sweating

Stroke volume can increase with dynamic exercise due to an: A) increase in sympathetic stimulation B) increased end-diastolic volume C) metabolic vasoconstriction in skeletal muscle D) decreased venous return

B) increased end-diastolic volume

formula for MAP

MAP=DBP + 1/3 ( SBP-DSP ) or MAP = CO x TPR

What are the three variables used to calculate oxygen consumption?

Stroke volume, heart rate, and arteriovenous difference

fick equation

VO2 = CO x a-vO2 difference

factors that influence afterload

anything that opposes ventricular ejection 1. peripheral resistance (primary factor during exercise) 2. viscosity of blood 3. valve dysfunction

PNS

dominant at rest, more stimulation= lower heart rate, less stimulation= higher HR. innervates SA and AV nodes

SNS

dominate during exercise and stress, more stimulation= higher HR, less stim= lower HR. innervates nodal tissue and contractile tissue

blood flows

down a pressure gradient- high to low normal systolic Bp = 120 mmHg

effect of a larger pressure difference

increased blood flow

veins

low pressure system and deoxygenated blood

glucagon

the hormone of "starvation" and promotes the mobilization of these fuels when nutrient supply is low

blood flow to skin during high intensity exercise

vasoconstriction, to conserve CO

blood flow to skin during moderate intensity exercise

vasodilation, cooling response

preload dictates

ventricular filling pressure

preload can be influenced by...

ventricular filling time, ventricular compliance, atrial systole

preload

volume of blood in chamber before contraction

end diastolic volume

volume of blood in each ventricle at end of diastole- filling phase

end systolic volume

volume of blood remaining in each ventricle after systole- contraction phase

if resistance increases, what happens to ΔP in order to maintain blood flow?

ΔP must increase

what cells secrete insulin?

β cells

what does vasodilation of skeletal muscle cause?

decreased TPR

effect of increased resistance on Q

decreased blood flow

how do we get more blood flow to working muscles?

1. increase cardiac output 2. shunt blood flow, send more to working muscles 3. decrease TPR 4. vasodilation in working muscle

breakdown of a triglyceride results in...

1 glycerol and 3 FFA's

3 ways stretching of cardiac muscle results in greater tension

1. creates optimal actin/myosin overlap 2. myocites become more sensitive to calcium 3. opening of stretch-activated Ca channels

cardiac output

= blood flow =how much blood is being delivered to muscles

Increasing calcium levels in the cardiac myocytes is the primary mechanism for: A) Increasing contractility B) Increasing heart rate C) Decreasing TPR D) Increasing preload

A) Increasing contractility

VO2max is greater in aerobically trained individuals primarily due to an increase in: A) maximum heart rate B) a-vO2 difference C) end systolic volume D) stroke volume

A) maximum heart rate

Deoxygenated blood from the veins first reaches the ______________ before being transported to the lungs. A) Left Atrium B) Right Atrium C) Left Ventricle D) Right Ventricle

B) Right Atrium

Which of the following would likely increase during acute exercise? A) Venous oxygen content B) a-vO2 difference C) Arterial oxygen content D) Liver blood flow

B) a-vO2 difference

An increase in which of the following could increase left ventricular stroke volume? A) contractility B) afterload C) ESV D) parasympathetic stimulation

B) afterload

Factors contributing to an increase in stroke volume with exercise include: A) increased EDV, decreased ejection fraction, and increased SNS stimulation. B) increased venous return, increased plasma epinephrine, and increased contractility. C) decreased venous return, increased PNS activity, and increased ESV. D) increased preload, increased SNS stimulation, and increased EDV.

B) increased venous return, increased plasma epinephrine, and increased contractility.

In an unacclimated individual, which of the following would be greater at any given exercise intensity when exercising in a hot environment compared to exercising in a cooler environment? A) Central blood volume B) Stroke volume C) Heart rate D) Muscle glycogen content

C) Heart rate

Which of the following would impair/reduce the ability to cool the body during exercise? A) Water ingestion B) Exercising in your underwear C) High relative humidity D) Cloudy day

C) High relative humidity

Why does exercising in a full football uniform result in greater rise in core temperature during exercise? A) Enhances convection B) Reduces skin blood flow C) Limits evaporation of sweat D) Prevents sweat loss

C) Limits evaporation of sweat

Trained individuals have a greater capacity for heat dissipation because of: A) increased skin blood flow B) decreased sweat rate C) increased VO2max D) decreased blood volume

C) increased VO2max

Heat acclimatization improves heat dissipation by: A) increasing heart rate during exercise B) decreasing VO2 max C) increasing sweat production D) decreasing skin blood flow

C) increasing sweat production

formula for cardiac output

CO = HR x SV

Which of the following would result in an increase in ejection fraction A) Increased afterload B) Decreased preload C) Increased venous return D) Increased contractility

D) Increased contractility

What is one reason why excessive sweating could result in a reduction in exercise performance? A) Lower heart rate B) Lower plasma volume C) Increased skin blood flow D) Increased plasma sodium

D) Increased plasma sodium

Which of the following does not increase with increasing exercise intensity? A) Heart rate B) Stroke volume C) SNS stimulation D) PNS stimulation

D) PNS stimulation

Which adaptation aids the trained athlete in reaching a higher preload in the left ventricle and, thus enhanced exercise performance? A) Increased skeletal muscle capillary density B) Reduced sympathetic stimulation C) Increased parasympathetic stimulation D) Plasma volume expansion

D) Plasma volume expansion

1. Measurement of carbon dioxide production and calculations of ____________ help determine the contributions of fat and carbohydrate to the energy expenditure of the activity. A) Heart Rate B) Stroke Volume C) Minute Ventilation D) Respiratory Exchange Ratio

D) Respiratory Exchange Ratio

Using a fan during exercise will promote body cooling by facilitating: A) evaporation and convection B) convection and conduction C) radiation and evaporation D) conduction and evaporation

D) conduction and evaporation

During dynamic exercise, blood flow increases specifically to active skeletal muscle largely as a result of: A) an increase of sympathetic vasoconstrictor nerve activity. B) shunting of blood to the liver. C) an increase in parasympathetic nerve activity. D) local production of vasodilator metabolites.

D) local production of vasodilator metabolites.

During dynamic exercise, e.g. running, diastolic blood pressure often remains stable or decreases. Which of the following physiological changes that occur with exercise could account for the effect of exercise on diastolic blood pressure? A) an increase in contractility. B) a decrease in total peripheral resistance. C) an increase in preload. D) the shunting of blood to the skin.

D) the shunting of blood to the skin.

formula for ejection fraction

EF = ( SV / EDV ) *100

Insulin's effect on Liver

Higher storage of glucose Higher glycogen synthesis Lower gluconeogenesis Promotes conversion of glucose to fat

Insulin's effect on Skeletal Muscle

Principle site of glucose disposal Increased glucose uptake Higher glycogen synthesis Higher glucose breakdown and oxidation, which promotes formation of triglycerides Higher protein synthesis Lower protein degradation

path of blood flow

Right atrium→ right ventricle → contraction → lungs → left atrium → left ventricle → contraction → aorta → tissues

stroke volume formula

SV = EDV - ESV

afterload

The pressure the ventricle must generate to eject blood.

insulin

When nutrients are in excess, insulin stores the excess as fuel.

a-vO2 difference

a- arterial O2 content v- venous O2 content difference- how much O2 was extracted from the arterial blood

what cells secrete glucagon?

alpha cells

pressure gradient

blood flows from high to low pressure

oxygen extraction during exercise

can increase three fold, decreased venous oxygen, greater a-vO2 difference

systole

contraction phase

low CHO diet

dec muscle glycogen stores and dec aerobic exercise time to exhaustion

relationship between blood flow, pressure, and resistance

flow is directly proportional to blood pressure gradient and inversely proportional to resistance Q (blood flow) = ΔP (change in pressure) / R

Glucogeonesis

glycogen (stored glucose) --> glucose

starling's law

greater stretch of the cardiac muscle results in greater force of contraction

arteries

high pressure system and oxygenated blood

effects of static exercise on SV

impedes venous return--> lower SV

effects of dynamic exercise on BP

inc SBP, DBP may dec due to dec vascular resistance, little to mod increase in MAP

effects of static exercise on BP

inc TPR --> dec flow, SBP and DBP inc, MAP inc due to DBP inc

how does glucagon work to increase blood sugar levels

inc gluconeogenesis to raise blood glucose levels

high CHO diet

inc muscle glycogen stores and inc aerobic exercise time to exhaustion

effects of CHO consumption during aerobic exercise

inc time to fatigue and maintains power output during prolonged exercise

preload increase

increased venous return = increased EDV = increased tension = increased force of contraction

effects of static exercise on CO

increases due to increased HR

order of carbohydrate supply for active muscles from largest to smallest

muscle glycogen > liver glycogen > plasma glucose

Islets of Langerhans

pancreatic cells that secrete glucagon and insulin

primary energy sources during long term (~4 hr) exercise, after muscle glycogen has depleted

plasma FFA's and adipose tissue triglycerides

three things that contribute to SV

preload, afterload, contractility

glucagon action on the liver

promotes synthesis of glucose promotes gluconeogenesis promotes glycogen breakdown and inhibits synthesis enhances glucose release

diastole

relaxation phase

which side of the heart is smaller and why

right side is smaller- less muscle since there is lower pressure because the pulmonary circuit is smaller than systemic.

how does insulin work to lower blood sugar

stores glucose as glycogen to lower glucose content in blood

effect of length-tension relationship on cardiac muscle

stretching of cardiac muscle gives optimal actin/myosin overlap and increases passive tension. both contribute to greater force production