Chapter 2 in IB textbook: Exercise Health

Erythropoietin

(EPO) is responsible for simulating red blood cell production. This may be injected illegally in order to produce more blood cells in the body (see next slides).

rebreathing (case study)

(using a paper bag when hyperventilating) when someone breathes back in the CO2 and restores arterial carbon dioxide levels.

VE

(volume exhaled) describes the volume of air being exhaled per minute

The process of breathing and how exercise affects this process:

1) Oxygen rich air is inhaled through mouth or nose (this can be voluntary or involuntary). In order for air to be breathed in, air pressure in the lungs needs to be lower than in the atmosphere. 2) As air is inhaled, the diaphragm pulls downward (w/ the help of other chest muscles) and increases the volume of the lungs. This volume increase reduces pressure in the lungs causing air to flow from the atmosphere in to the lungs. 3) No energy is required for exhalation. The lungs recoil and increase in pressure so that air flows out through the mouth again. 4) During exercise, active muscles need more oxygen, thus inhalation needs to occur at a faster rate. During exercise, lung size can increase to an even greater volume and chest muscles can compress the lungs at a faster rate, allowing fast breathing.

Two loops of circulation of blood in the heart

1) Pulmonary circulation 2) Systemic circulation

specialist cells in the heart and their functions:

1) Sinoatrial node (pacemaker or SAN) - stimulates heart muscle contractions 2) Atrioventricular node (AV node) - slows the electrical current sent by (SAN), serves as an electrical relay system 3) Purkinje Fibers - fibers spread out through atria and ventricle walls, transfers electricity across the bottom of the heart 4) Bundle of His - transmit electrical messages from the AV node, the bundle of Purkinje fibers.

What two ways may VO2 max be expressed?

1) absolute VO2 max is reported in L/min 2) relative VO2 max is the same value but normalized according to body mass in ml/kg/min Example: when doing weight bearing activities it makes more sense to use relative VO2 max because it accounts for an individual's size and mass. Size and mass is important because the variability between people in active muscle mass, heart size, and blood volume.

Adaptations from endurance training:

1) larger cardiac output 2) more effecting blood shunting (redistribution) 3) increase in skeletal muscle microcirculation (ratio of capillaries to muscle fibers) 4) capillarization- new blood vessels + capillaries develop in new parts of the body for blood to be delivered to.

process of specialist cells working in the heart

1) pacemaker sends impulse trough walls of atria to atrioventricular node 2) this cause muscles in atria to contract simultaneously & increase pressure in atria, forcing blood from the atria though the AV valves into the ventricules 3) AV valves then close 4) Impulse is then conducted via the Bundle of His along the Purkinje Fibers that spread the impulse across the ventricle walls 5) This causes the fibers in the wall to contract at the same time, increasing pressure and forcing the blood up through the main arteries to leave the heart 6) Semi-lunar valves at the opening to main arteries close 7) Cycle starts again

2 ways that represent the decrease of our body's need to breathe as a result of hyperventilation:

1) rebreathing 2) holding breath

Resting, healthy adult's systolic and diastolic blood pressures:

120mmHg (systolic) 80mmhg (diastolic)

lungs have...

A very large surface area, good blood supply, and the distance between blood and the alveoli is very thin.

O2 and CO2 as they diffuse in the lungs

Air breathed into the lungs is high in oxygen and low in carbon dioxide. Blood being pumped via the heart to the lungs is low in oxygen and higher in carbon dioxide. Therefore, oxygen will diffuse from the alveolus in the lungs across the pressure gradient into the blood while carbon dioxide diffuses from the blood through the pressure gradient into the alveolus. (The opposite occurs when oxygen is being transferred to different muscles and parts of the body for use).

Breathing sequence:

Air goes through conducting airways (nasal and oral passage ways, trachea and bronchi), is moistened by the airway linings, goes to the smaller bronchi branches and eventually end up in small air sacs called alveolus. Gas exchange takes place here (where Oxygen and Carbon dioxide enter the blood). (Nolan Makes Pumpkin Lattes To Be (a) Barista Like Andrew) Stands for: Nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, lungs, alveoli.

white blood cells (leucocytes)

Are primarily used in immune functions and protecting the body from infection. They combat disease possible infections.

capillaries

Are very narrow, have very thin walls, and form the branching network through tissues where exchange of Oxygen between the blood and tissues occurs.

cardiac output equation:

Cardiac output (liters per min) = heart rate (beats per min) X stroke volume (milliliters per min) /100

Cardiac output and venous O2 difference between children and adults:

Cardiac output of child cycling: 9.4 L/min Cardiac output of adult cycling: 12.4 L/min Cardiac output of child running: 6.7 L/min Cardiac output of adult running: 12.3 L/min Venous O2 difference of child cycling: 11.1 ml/100ml Venous O2 difference of adult cycling: 8.9 ml/100ml Venous O2 difference of child running: 8.7 ml/100ml Venous O2 difference of adult running: 8.4ml/100ml *Conclusion: Cycling is more difficult for the child because he/she is so small and does not have many large muscles in only their legs.

cardiovascular drift

Cardiovascular drift: when cardiac output remains the same yet the heart rate is slowly and progressively increasing as a result of a decrease in stroke volume

Pressure gradients during exercise

During exercise, the pressure gradient at the tissues and lungs becomes greater as more oxygen is being used up and more carbon dioxide is being produced. The challenge for the lungs is to maintain resting partial pressures in the alveoli. This is achieved by breathing out the air with less oxygen and more carbon dioxide and then breathing in fresh air to maintain the pressure gradients for diffusion to occur.

purpose of the heart valves

Ensure that there is no back flow of blood and enables an increase in the chambers so that blood can be ejected

features of the heart

Four chambered, double pump system, separated by a septum, contains SA and AV nodes, 4 valves, and sends blood to the upper and lower body.

At what rate does one's VO2 max begin to decrease?

From adulthood, VO2 max tends to decrease by 1% each year. (This means a decline in endurance capacity, due to injury). There are exceptions to this rule however.

arteries

Have a large diameter, thick muscular walls, and the blood exerts a large amount of force on these walls. Responsible for taking blood AWAY from the heart to bodily tissues. Easy to remember because Arteries go Away (both "A").

Cardiac output depends on...

How fast the heart is beating and stroke volume

What would limit VO2 max?

Limitation comes from the inability of the cardiovascular system to deliver oxygen. There are exceptions to this (ex/ extremely high aerobic fitness levels).

Testing VO2 today

Tests of physiological functions used to only be done for research. Today these tests are done in a variety of ways in a variety of places (ex/ hospitals). This is partly do to technology. (Refer to bike image in textbook as visual).

Why do children have much smaller cardiac outputs than that of adults?

The Venous O2 difference in children help compensate for this lower output compared to adults in order to achieve similar VO2.

How will the type of exercise being performed effect one's VO2 max?

The more muscle mass being used during exercise, will promote the use of oxygen and thus a greater VO2 uptake. (ex/ running requires more Oxygen then cycling) ex/ cross country skiers, who work both their upper and lower body, is an example of an athlete who is known for their high VO2 maxes.

VO2 max measurements (in the world)

There are records of one's VO2 max being larger than 90ml/kg/min in men and 75 in females, while is has also been recorded to reach as low as 20ml/kg/min

platelets

These are cell fragments in the white blood cells and assists in the process of repair following an injury. They form blood clots and prevent (excess) bleeding.

Factors that stimulate or inhibit ventilation:

These include gas partial pressures, acidity, temp, and hormones. The contribution of these factors depends on characteristics of the exercise (ex/ intensity, duration) (ex/ oxygen receptors increase ventilation when someone is at a high altitude)

untrained male vs trained male cardiac output

Untrained: Rest: 4.6 liters/min Max: 19.7 liters/min Trained: Rest: 4.5 liter/min Max: 32.2 liters/min

untrained male vs trained male stroke volume

Untrained: Rest: 60 ml/beat Max: 120 ml/beat Trained: Rest: 90 ml/beat Max: 190 ml/beat

untrained male vs trained male heartbeat

Untrained: rest: 75 beats/min max: 197 beats/min Trained: rest: 50 beats/min max: 195 beats/min

Calculation/formula for VE

VE=VT(Bf) volume exhaled= tidal volume x breathing frequency

Fick equation

VO2 Max = maximum cardiac output X maximum aterio-venous oxygen difference

How does training affect VO2 max?

VO2 max can be increased as a result of adaptations in the cardiovascular system (central adaptations), heart, and muscle (peripheral adaptations). The increase in VO2 can be a result of increase stroke volume, though heart rate does not change with training. The increase of stoke volume is mainly a result of increased volume in the left ventricle (more blood per contraction). Muscles can also develop more capillaries that give muscles more oxygen.

Does age effect one's VO2 max? If so, how?

VO2 max peaks in the early 20s for males and mid-teens for females. Children generally have a lower VO2 max then adults because they are much smaller. However, when the values are normalized to body mass, male children and adults have very similar VO2 values. For women, VO2 max increases with growth, though tends to decrease in teen years. This is partly due to body composition.

As oxygen demand increases, so does the ________

VO2 max. These variables will increase until the VO2 max limit is reached. Someone can still be doing activity, but they would soon have to stop. For this reason, VO2 max is also known as aerobic capacity.

Does gender have an effect on VO2 max? If so, how?

VO2 maxes are generally lower in females because of size differences, body composition, and lower hemoglobin content then men. (i.e. more muscle mass in men requires a higher VO2 max in order for all muscle to receive the adequate amount of blood during exercise).

the left and right side of the heart

Work simultaneously (both the right and left atrium's receive blood, push it to the right and left ventricles, then push it out of an artery into the body.

The partial pressure in oxygen is ____a_______ in arterial blood supplying exercising muscles than in the muscle tissue. Therefore, oxygen will diffuse ___b_____ the blood ____c_____ the muscle.

a) higher b) from c) to

The partial pressure of carbon dioxide is _____a_____ in the lungs (alveoli) than in the blood returning from exercising muscles. Therefore, carbon dioxide will diffuse __b___ the lungs ____c____ the blood.

a) lower b) to c) from

During exercise, blood will primarily flow to the...

active muscles. There, more capillaries will open within the network of muslces. The amount of capillaries taking blood to other muslces will close to prevent a drop in blood pressure throughout the entire system and reduce blood flow to those organs.

Arteries branch into smaller ________

arterioles

Injecting EPO

athletes can inject a synthetic EPO to get the same results as blood doping.

diastolic blood pressure

blood pressure between the heartbeats when the heart is relaxed

systolic blood pressure

blood pressure when the heart is contracting

Heart is also a tissue that needs to be supplied with oxygen through _________

coronary arteries

veins

deliver deoxygenated blood from tissues BACK (TOWARDS) to the heart. They are less muscular and fiberous than arteries. The pressure in them is low, they are flexible, and have valves (in the larger veins) that prevent back flow.

pulmonary circulation

delivers blood from the right side of the heart to lungs for oxygenation, then back to the left side of the heart

systemic circulation

delivers oxygenated blood from the left side of the heart to other tissues in the body where oxygen is used up, then the deoxygenated blood is brought back to the right side of the heart.

myogenic contraction

describes how the heart can contract without nerve stimulation. A sequence of these contractions initiates a specialist group of cells (the pacemaker/sinoatrial node)

You need both _____ and _____ to produce health?

food and exercise

pacemaker/sinoatrial node

found in the wall of the right atrium. The rate at which it contracts the heart can be affected by the following factors: 1) hormonal stimulation 2) drugs 3) automatic nervous system (involuntary) by adjusting the parasympathetic and sympathetic branches (ex/ of homeostasis by increasing or decreasing amount of neurotransmitters)

as the intensity of an exercise increases, so does the _______ and __________

heart rate and stoke volume, and thus the cardiac output until it reaches its maximum rate and volume. If exercise is maintained at the same level, cardiac output will also remain consistent. While the stroke volume will slowly decline, the heart rate will slowly increase slightly.

The cardiovascular and ventilator systems are essential in maintaining...

homeostasis during exercise.

exercise is a good indicator of...

how efficient the systems in our body are working

heart rate

how fast the heart is beating (heart rate in beats per minute)

when exercise becomes harder, ventilation_____

increases and the arterial partial pressure of oxygen is preserved.

hemoglobin

iron rich pigment in blood that oxygen attaches itself to in order to be transported. (oxygen attaches to Iron on hemoglobin in the lungs, then releases by active tissue (muscles)).

BF

is breathing frequency (number of breaths)

Diameter of arteries, arterioles and capillaries need to be relatively consistent to

keep blood pressure at a constant level

Blood pressure __________ as is goes from the arteries to the arterioles and then capilarries.

lessens

Pressure in the veins and venules are relatively _____

low and consistent

Homeostasis

maintenance of a constant internal environment (many internal systems in the body must continuously work together to do this). *Homeostasis is hard to regulate during exercise.

red blood cells (erythrocytes)

make up 40-45% of blood volume (which is known as hematocrit). Used mainly for transport of materials (especially hemoglobin/oxygen).

Hemoglobin concentration may be manipulated by...

manipulating the hormone erythropoietin, more oxygen can be transported and aerobic performance will improve. (training in high altitudes). However, the levels of hemoglobin following high altitude training may go back to normal, not a permanent adaptation. *The same results from altitude training can be achieved through illegal methods. (ex/ blood doping, injecting EPO)

plasma

material that makes up 55% of blood and contains dissolved substances.

VO2 max is a good indicator of someone's ________

overall fitness. As VO2 max expresses overall cardio-respiratory fitness

blood composition

plasma, red blood cells, white blood cells and platelets.

parasympathetic nerve system

regulate's body's unconscious actions of relaxing the body (and very often slowing down heart rate)

sympathetic nerve system

regulates body's unconscious actions "flight-or-fight" response. Part of the nervous system that prepares the body for intense physical activity (and very often speeds up the heart rate)

Blood doping

removing blood with high hemoglobin content then storing it to use before a competition so that they have a higher O2 intake.

partial pressure

represents the pressure exerted by a single gas

The diameter of arteries, arterioles, and capillaries is maintained through _____

smooth muscle, which lines the walls.

Fick equation purpose

summarizes the relationship between maximum cardiac output , maximum arterio-venous oxygen difference and VO2 max.

stroke volume

the amount of blood being ejected with each contraction (milliliters per beat)

cardiac output

the amount of blood ejected from the left side of the heart (therefore supplying the whole body except the lungs) (in litres per minute). Directly proportional.

Oxygen uptake/VO2

the amount of oxygen taken into the body and used (a good indicator of how well internal systems are working together) VO2 may be measured to evaluate health and fitness in an individual.

Bicarbonate

the form in which CO2 is transferred from the body tissues to the heart in the blood.

hyperventilation

the increase in ventilation above what is actually required to meet oxygen demands. This causes us to breathe out more CO2 and thus our CO2 levels create less desire for our body to breathe.

VO2 max

the maximum amount of oxygen that the body can take in and use Is measured by the gas concentration and volume of air being breathed out at progressively increasing intensities of exercise

physiology

the study of how the body functions

gas exchange

the transfer of carbon dioxide and oxygen between systems

To maintain resting gas partial pressures in the lungs and arterial blood supply to active tissues...

the volume of air is increase as a result of more breaths and a greater tidal volume during exercise.

If all the smooth muscle in the walls of arteries, arterioles, and capillaries were relaxed...

then blood could not return to the heart because there is no pressure. Thus the nervous and cardiovascular system work together work together to contract some parts and relax others to maintain pressure.

Holding breath (and effects)

this can be achieved for long periods of time when someone hyperventilates before hand to lower carbon dioxide levels.

VT

tidal volume

main function of blood during exercise

to transport materials (gases, nutrients, waste products, hormones, or heat) to and from tissues.

___________ thicken to form veins

venuoles

diffusion

where gas will move along a gradient from an area of higher partial pressure to a lower partial pressure.