Exercise Science Chapter 3

Nora is the subject in a laboratory experiment where they will determine physiological responses to exercise. Before she exercises, they will take baseline measurements while she rests in a chair. At rest, Nora has her blood volumes and gases analyzed as well as her respiratory gases. Her resting heart rate was measured at 65 bpm, her stroke volume was measured at 75 ml/beat, and her arterial blood contained 20 ml of oxygen per 100 ml of blood and her venous blood contained 15 ml of oxygen per 100 ml of blood. What is her ABSOLUTE VO2 at rest?

.24 L/min .24 L O2/min

Plasma

50% of the blood's volume sweat is a derivative of plasma when plasma is lost, osmolarity of the blood increases, can negatively affect performance (>2%)

average heart impulse

60-80 times per min

Which of the following statements is TRUE? Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a The middle, muscular layer of the heart wall is known as the endocardium. b The SA node is a group of autorhythmic cells that depolarize (fire) at regular intervals. c The heart is approximately the size of a golf ball. d The heart has three chambers, two upper atria and one lower ventricle.

The SA node is a group of autorhythmic cells that depolarize (fire) at regular intervals.

stroke volume

The amount of blood ejected from the heart in one contraction

action potential

change of electrical state in a cell- stimulates and allows transmission of a signal

what needs to happen for cellular metabolism to take place?

each cell needs to receive a constant supply of oxygen and nutrients

3 layers of the heart

epicardium, myocardium, endocardium

parasympathetic division of autonomic nervous system on the cardiovascular system

exerts it's influence on the cells of the SA node at rest promotes conversion of energy of and a reduced heart rate "rest and digest"

Chronic adaptations to exercise will improve the efficiency of the body's physiologic function - for example, energy production within cells and the efficiency of the cardiovascular system - during exercise but has no effect on the body's physiologic function during rest.

false

The sympathetic nervous system adapts to exercise training leading to a person having a higher maximal heart rate during exercise.

false

When an individual performs physical activity or exercise in a hot and/or humid environment, the blood flow to the skin is reduced and more blood will be directed to the internal environment.

false

Purkinje fibers

fibers in the ventricles that transmit impulses to the right and left ventricles, causing them to contract

capillaries

have considerably thinner walls compared to arteries and veins which make them well suited s sites of exchange for gasses, nutrients, and waste

relationship between heart rate and workload

heart rate increases in a linear fashion with increased workloads

thermoregulation

heat is a byproduct of physical exertion vasodilation of blood vessels in the skin to allow for heat loss blood carries heat to the body surface where it can be lost by radiation (flushes skin)

blood vessels

hollow tubes that allow blood to flow from the heart to tissue and back

a-v O2 difference

how much O2 is extracted by the tissues difference in O2 concentration in the atrial and venous circuits more O2 extracted, greater difference as mechanical activity increases, more O2 will be extracted from the blood

how does the myocardium contract at rest

in a rhythmic manner

how does the cardiovascular system respond to increased demand for O2 and nutrient delivery by:

increased heart rate

blood doping

increasing a person's hematocrit by taking synthetic erythroprotein

endocardium

innermost layer of the heart a single layer of flattened cells that is very similar to the lining of blood vessels. helps to regulate the function of the muscular myocardium

what does the body do to the nutrients that are in the highest demand?

it can redirect delivery of nutrients and O2 to those tissues

what happens once the impulse leave the av node

it reaches the bundle of his at the base of the ventricles the bundle of his bifurcates into the right and left bundle branches which run along the thick interventricular septum

Bundle of His (AV bundle)

located next to the AV node; provides the transfer of the electrical impulse from the atria to the ventricles

Thermodynamics

mechanisms involved in blood flow --->changes as bod adapts to internal and external enviornment changes with physical exertion, changes in temp, hormonal flunctuations

Myocardium

middle muscular layer of the heart thickest layer, made up of cardiomyocytes (the contractile cells of the heart) when myocardium of ventricles contract, blood is moved into the pulmonary or systemic unit

red blood cells

most abundant, transport oxygen from lungs to body tissues

Regular exercise results in the following change that would improve health in a person with cardiovascular disease.

none of these

heart rate

number of times the SA nodes fires each minute

heart bundle branches

off shoots of the bundle of his in the heart's ventricle

blood vessel 3 layers

outer fibrous layer middle muscular layer thin inner lining (endothelium)

epicardium

outermost layer of the heart is a part of the serous membrane that reduces the amount of friction between closely associated structures within the mediastinum

what happens as we transition from rest to exercise

oxygen demand and consumption increases, myocardium and skeletal muscle require more energy

Hematocrit

percentage of blood volume occupied by red blood cells

Where is cardiac output redirected to

working muscles and away from the liver, kidneys intestines

Is Ben's resting a-v O2 difference within normal range?

yes

without the external influence of neural or endocrine signaling, SA node will fire ___ times per min

100

normal venous O2 content

12-15 ml/dl

average a-v O2 difference during exercise

15-20 ml/dl of blood

normal arterial O2 content

17-20 ml/dl

Kate went in for baseline testing for a research study she is participating in. She was told that she has a resting heart rate of 75 bpm. Her resting stroke volume is 244 ml/beat. Her calculated resting cardiac output is blank1 - Word Answer L/min. Does this fall within normal physiological range? blank2 - Word Answer

18.3 18.3 L/min 18.3 L 18.3L, no

how much hemoglobin per each red blood cell

250,000 hemoglobin each carries 4 O molecules

Sam is the subject in a laboratory experiment where they will determine physiological responses to exercise. As Sam exercises, he has his blood volumes and gases analyzed as well as his respiratory gases. At one point of the exercise test, his heart rate was measured at 180 bpm, his stroke volume was measured at 140ml/beat, his arterial blood contained 20 ml of oxygen per 100 ml of blood and his venous blood contained 5 ml of oxygen per 100 ml of blood. What is his ABSOLUTE VO2 at this workload? blank1 - Word Answer

3.78 L O2/min 3.78 L/min

normal blood hematocrit female

37%-47% hematocrit

Ben's arterial blood oxygen is 20 ml O2 per 100 ml blood. His venous blood oxygen is 16 ml O2 per 100 ml blood. What is his a-v O2 difference?

4 ml O2/100 ml blood

average a-v O2 difference at rest

4-6 ml/dl of blood

Quincy has a resting heart rate of 60 bpm and a resting stroke volume of 75 ml/beat.Quincy's resting cardiac output is __ L/min. (round to nearest tenth)

4.5

Larry is a 25 year old male of average height and weight. His resting heart rate is 70 bpm and his resting stroke volume is 70 ml/beat. At rest, his cardiac output is ___ L/min.

4.9

normal blood hematocrit male

42%-52% hematocrit

The average cardiac ouptut blank1 - Word Answer is L.min

5

VO2 max

How much O2 your tissues are consuming at a given workload (ex. rest, while jogging, etc) VO2= cardiac output x a-v O2 difference

Can you summarize how the cardiovascular system adapts to increased physical activity?

The cardiovascular system adapts to increased physical activity with increased heart rate and myocardium force, and by redirecting the delivery of nutrients and oxygen to the organs that are the highest in demand (the muscles being that are worked). The heart responds to the increased demand of nutrients and oxygen in the muscles by pumping blood more forcefully and faster. The sympathetic division of the autonomic nervous system communicates with the heart to do so. During physical activity, the heart also pumps a higher percentage of blood towards the muscles being worked, while organs like the liver receive a lower percentage of blood. This is because the muscles need a higher percentage of blood to receive the nutrients and oxygen they need to generate ATP in order to continue exercising.

cardiac output

The volume of blood ejected from the left side of the heart in one minute (how much oxygenated blood is directed to the tissues) heart rate x stroke volume increases with exercise intensity at rest = 5L/O2

Fick equation

VO2 = Q x a-vO2 difference The equation for oxygen consumption

blood

a connective tissue that flows through the heart and blood vessels

the heart

a fist-sized muscular organ that rests between your lungs within the mediastinum responsible for generating force to move blood from chamber to chamber and into the great vessels that extend from the base of the heart

The Fick equation is used to determine oxygen consumption (VO2) at a given workload. The Fick equation states that oxygen consumption is a product of cardiac output and _.

a-v O2 difference

the av node

acts as a pacemaker in case of SA node failure

what happens every time the SA node depolarizes

an electrical impulse travels from the SA node along the atrial walls impulse causes cells of atrial myocardium to depolarize and initiate contraction The impulse will reach another region of the cardiac cells (AV node) This cluster of cells will transmit the impulse to the ventricles but the impulse will be delayed. The atria are allowed time to complete contraction before ventricles are stimulated to contract

oxygen is delivered to our cells by

an expansive vascular network

pulmonary artery

artery carrying oxygen-poor blood from the heart to the lungs

Hemoglobin

binds O2 and transports through blood bc O2 doesnt dissolve well in plasma

when the myocardium of the atria contract

blood is moved into the ventricles

what happens to blood vessels during exercise

blood vessels that feed into disgestive organs vasoconstrict, causing a reduced delivery of oxygen rich blood, while blood vessels feeding into skeletal muscle will vasodilate causing an increased delivery of oxygen rich blood

blood vessel resistance to blood flow

can increase or decrease diameter of the lumen

Gas and nutrient exchange occurs in the _.

capillary beds

arteries

carry blood away from the heart (usually oxygenated)

white blood cells

carry out immune responses

pulmonary veins

carry the oxygenated blood from the lungs into the left atrium of the heart

erythroprotein production by kidney is stimulated by

decreased O2 concentrations in the blood

sinoatrial (SA) node

primary pacemaker of the heart (generates action potential) if left uninhibited, likely to fire (depolarize) 100 bpm

Thermoregulatory mechanics

processes that are used to help maintain a relatively unchanging core temp when you sweat, a portion of plasma is lost through the sweat pores to cool the body plasma aids in transporting heat away from working muscles to the blood vessels near the skin surface

sympathetic division of autonomic nervous system on the cardiovascular system

promotes mobilization of energy stores, increased heart rate, and stroke volume "fight or flight"

Which of the following are functions of the cardiovascular system? Choose all that apply.

pumping deoxygenated blood through the pulmonary circuit regulating body temperature Correct Answer protecting the body from foreign pathogens aids in maintaining fluid balance transportation of nutrients

2 upper atria

receive blood from the systemic and pulmonary circuits, when they contract, they assist in filling the 2 lower ventricles

chronic cardiovascular responses regular, repeated stresses causes the body to adapt:

resting heart decreases (slower, more efficient) myocardium will contract more forcefully during exercise because the heart muscle gets stronger. increased filling the increased stroke volume ventricles fill with more blood before they contract

veins

return blood to the heart (usually deoxygenated)

path of blood flow throughout the heart

right atria--> right ventricle--> pulmonary circuit--> gas exchange-->left atrium-->left ventricle-->out to body--> arteries--> arterioles--> capillaries--> in tissues O2 is released from hemoglobin--> diffuses into cells-->deoxygenated blood returns to the heart

depolarization steps

sa node---> right and left atria depolarize impulse travels throughout atrial walls causing atrial myocardium to depolarize and initiate contraction impulse reaches the av node is delayed before the impulse travels to the ventricles impulse travels to the septum, reaches bundle of his branches into left and right purkinje fibers conduct impulse throughout ventricle walls, causing depolarization contraction

lumen

space within a tubular part or organ, such as the space within a blood vessel

The _ nervous system influences the heart to contract faster than it would if left uninhibited.

sympathetic

why does the heart pump

the heart pumps to circulate blood throughout the chambers of the heart and provides the force to move blood into arteries

autorhythmicity

the heart usually contracts (beats) at regular intervals due to a group of specialized cells within the myocardium that direct the myocardium to contract- cells exhibit this

compoments of the cardiovascular system

the heart, blood vessels, blood

Platelets

vital for clot formation in response to tissue damage

plasma

water, plasma proteins, dissolved solutes

osmolarity of blood

the total molarity of those dissolved particles that cannot pass through the blood vessel wall

Jack and Jill took a hike at Lums Pond. After 15 minutes, Jill complained to Jack that she was sweating through her shirt. Jack explained that sweating is necessary for Jill to properly ____.

thermoregulate

Functions of the cardiovascular system

transport regulation protection

A person's cardiac output is determined by the product of the rate of the heart contracting per minute and the volume of blood ejected from the ventricles per minute.

true

Oxygen moves from the atmospheric air, across the respiratory membrane, into capillaries that will deliver blood to the left side of the heart.

true

Synthetic erythropoietin, blood doping and training at high altitude increases red blood cell numbers in humans and this can lead to an improvement in aerobic endurance performance.

true

You are re-testing your client to determine the effectiveness of an endurance training program. You measure your client's resting heart rate before the exercise test. You note that the resting heart rate is lower than it was during baseline (initial) testing a few months prior. This change in resting heart rate is due to an increase in parasympathetic tone and is a normal, positive adaptation to training.

true

The __ are thick-walled chambers of the heart that are responsible for pumping blood to the lungs and body tissue.

ventricles

2 lower ventricles

ventricles are more muscular than the thin-walled atria allowing them to generate forceful contractions to pump blood to the lungs and systemic circulation

Acute Cardiovascular Responses to exercise

• Heart rate increases with exercise intensity (generally in a linear relationship) • Stroke volume increases • Cardiac output increases • Blood flow distribution changes (digestive system, organs, skin, muscles) • Blood pressure changes withdraw of parasympathetic influence sympathetic nervous system stimulates nodal cells to depolarize at a faster rate---> myocardium contracts more forcefully---> larger stroke volume