Cardiorespiratory system Flashcards
Blood composition and types
BLOOD PLASMA: Liquid substance of the blood. 55%. It helps transport all of the nutrients around the body.
ERYTHROCYTES: Help transport O2 and CO2.
LEUKOCYTES: Less than 1%. It helps fight disease, identify pathogens and remove them from the body.
THROMBOCYTES: Platelets. Help to form clots which prevent bleeding inside and outside the body and help to form scabs.
Anatomy of the heart
Four chambers: RIGHT ATRIUM, LEFT ATRIUM, RIGHT VENTRICLE AND LEFT VENTRICLE.
Four vessels:
PULMONARY ARTERY: Takes deoxygenated blood to the lungs.
AORTA: Takes oxygenated blood out of the heart and to the rest of the body.
PULMONARY VEIN: Brings in oxygenated blood from the lungs to the heart.
VENA CAVA: Supplies the heart with deoxygenated blood.
Four valves: They prevent backflow. PULMONARY VALVE, AORTIC VALVE, TRICUSPID VALVE, BICUSPID/MITRAL VALVE.
CORONARY ARTERY: Provides the heart its own blood supply, so it has got the oxygen to allow contraction to take place.
Pulmonary and systemic circulation
PULMONARY CIRCULATION
Blood circulates to the lungs.
It starts in the right ventricle. The pulmonary artery takes deoxygenated blood to the lungs to become reoxygenated and it does that by a gas exchange. After doing that, the blood returns to the heart via the pulmonary vein and enters the left atrium.
SYSTEMIC CIRCULATION
Blood circulates to the body systems.
As the blood leaves the left ventricle, it goes through the aorta, which takes oxygenated blood all over the body. It is the biggest blood vessel in the body, and it takes the blood to the muscles, the digestive system and wherever is required. Once the oxygen has arrived in the blood, it diffuses again, aerobic respiration takes place, carbon dioxide is diffused into the bloodstream and that leaves the blood deoxygenated.
Intrinsic and extrinsic regulation of heart rate
INTRINSIC: Within the heart.
The heart is myogenic, it creates its own impulse.
The SA NODE is responsible for both atrium contractions at the same time. It is located on the right atria. The ventricular contractions are via the PURKINJE FIBERS.
SA NoDe sends impulse to AV NODE (which is in the bottom of the right atria). AV node slows the impulse allowing atrial contraction to be completed.
Then, the AV node sends the impulse to the ventricle via the BUNDLE OF HIS.
After, it branches left and right into the ventricular walls to the purkinje fibers to allow ventricular contraction. This happens over and over again.
When people exercise or when adrenaline is secreted by the adrenal medulla, it directly affects the SA node, increasing the impulse and therefore heart rate.
EXTRINSIC: Not in the heart itself, it takes place in the CENTRAL NERVOUS SYSTEM. It impacts the heart. It comes from the AUTONOMIC NERVOUS SYSTEM. This is divided into SYMPATHETIC and PARASYMPATHETIC nervous systems.
SYMPATHETIC: Fight or flight. Increases heart rate. Within the lungs, the bronchi dilates. This allows more air into the bronchi. Digestive system is restricted with blood flow. Adrenaline also has an impact on glycogen and lipid breakdown for energy production. The priority is for the blood to go to the heart and the muscles. Dilate pupils, inhibit salivation, activity of stomach, gallbladder, activity of intestines, increase heart beat, relax airways, secrete epinephrine and norepinephrine, relax bladder.
PARASYMPATHETIC: Rest and digest. Decreases heart rate. Acetylcholine is the hormone that is released. This brings the heart rate back down to normal. Lungs’ bronchi constrict, not allowing much air in, bringing down to a normal breathing state. Promotes blood to the digestive system. Constrict pupils, stimulate saliva, slow heart beat, contrict airways, stimulate activity of stomach, stimulate gallbladder, stimulate activity of intestines, contract blandder.
Heart rate, Stroke volume & Cardiac output during exercise and between groups + cardiac hypertrophy
HEART RATE: Amount of times the heart beats per minute (bpm).
STROKE VOLUME: Amount of blood ejected from the heart per beat (ml).
CARDIAC OUTPUT: Heart rate x Stroke volume. Amount of blood that leaves the heart per minute.
During exercise
Immediate exercise: The three go up. Stroke volume increases, heart rate too, therefore cardiac output as well. This is because the demand for oxygen increases. Everything has to increase to provide the oxygen to the working muscles, to keep respiring and producing energy and keep moving.
Long-term effects: After a six week training program, for instance, the heart has changed. Cardiac output slightly increases. The relationship between stroke volume and heart rate changes.
CARDIAC HYPERTROPHY: The heart experiences strength as part of the aerobic and cardiovascular training, therefore it is bigger and stronger. The left ventricle wall strengthens resulting in increased stroke volume. Each contraction is more forceful.
Due to cardiac hypertrophy, there is less demand on the heart to beat often. The heart then is more efficient. Heart rate can decrease. Heart will also beat less during exercise because the athlete will be more efficient at providing muscles with oxygen. Less heart rate, more stroke volume, cardiac output has to remain constant.
MALES vs FEMALES:
Males have a slightly higher stroke volume.< Males have a bigger heart, so they produce a bigger stroke volume. Cardiac output is also slightly higher because of the heart’s size.
TRAINED vs UNTRAINED:
A trained athlete will have a much stronger stroke volume, because of cardiac hypertrophy, during rest and exercise.
YOUNG vs OLD.
The resting heart rate for a younger person will be slightly lower than the resting heart rate of an older person. During exercise, the heart rate increases much more for the younger person. The older person has a smaller range for exercise. The intensity cannot reach the same as a younger person. The stroke volume is stronger for the younger person because the heart is stronger. As people get older, the heart loses strength, so there is less strength in each contraction. Cardiac output reduces with age.
Cardiovascular drift
It is a thermoregulatory response to dehydration over 30 minutes of exercise. It involves cardiac output, stroke volume and heart rate.
It happens when the body enters a state of dehydration, due to the excess of heat or because the body heats because of exercise.
Heart rate increases in line with intensity. This always happens with exercise. The stroke volume and cardiac output start to flatten during submaximal exercise.
This flattening or PLATEAU gets affected by the VENOUS RETURN (amount of blood that returns to the heart per minute). Venous return is challenged when dehydrated. Blood plasma is lost to the skin and it leaves the skin through sweat. Therefore, there is less blood plasma in the blood, less blood going around the body, so more strain on the heart.
Once submaximal exercise exceed 10 minutes, the following occurs:
Heat is produced as a byproduct of energy production (ATP is broken to ADP + P and creates energy. Heat is a byproduct that is released).
So, core temperature is increased. Form 37º up to 40º, particularly when it goes beyond 30 minutes or in extreme heat.
Evaporation occurs at the skin, allowing heat to dissipate and as the fluid/sweat evaporates, the body cools down.
This causes a reduction in blood plasma, increasing blood viscosity (thickness). In turn, reducing stroke volume and venous return.
This reduction in stroke volume places an increased demand on the heart rate to maintain a steady cardiac output.
Every ten minutes, the stroke volume decreases and heart rate increases. Cardiac output remains constant.
Systolic and diastolic blood pressure
Blood pressure is the amount of force exerted against arterial walls.
Measured in mmHg (millimeters of mercury).
SYSTOLIC: Contract and spill. Force exerted on arterial walls as blood is ejected from the ventricles (contraction). Contracted ventricles, arteries stretch.
DIASTOLIC: Relax and fill. Force exerted on arterial walls as blood fills the ventricles (relaxation). Relaxed ventricles. Arteries go back to normal and by doing so push blood too.
Above 140/90: HIGH.
120/80: GOOD.
Below 90/60: LOW.
Systolic and diastolic blood pressure data at rest and during exercise and response to static and dynamic exercise
During exercise, systolic pressure increases and diastolic stays the same or slightly decreases.
DYNAMIC EXERCISE RESPONSE: Where a muscle contracts, the opposite relaxes, etc. Example: a run, a press up. Isotonic muscle contraction. Systolic blood pressure increases and diastolic decreases.
STATIC EXERCISE: Weightlifting. Holding a weight out to the side in a T-shape working on your shoulders. Isometric muscle contractions. Example: a plank. Systolic increases and diastolic as well.
Static and dynamic exercise both increase cardiac output.
Dynamic exercise recruits a greater number of muscle groups than static exercise. Therefore, more muscle will experience dilation in the blood vessels. There is more blood, more dilation, so when we are relaxing there is a reduction in diastolic. The squeezing of the heart will increase, but the blood vessels going to the muscles of the body will dilate.
Less muscle groups are recruited during static exercise, however, an increase in cardiac output is still experienced. Therefore, an increased blood flow in the non-recruited muscle groups occurs, as the vessels are in a more constricted state.
At rest: 5 liters
During exercise: 25 liters/minute.
Digestive organs
20-25% (1-1.25l)
5% (1-1.25l)
Heart
5% (250ml)
5% (1.25l)
Skin
5% (250ml)
3% (750ml)
Bones
5% (250ml)
1% (250ml)
Brain
15% (750ml)
3% (750ml)
Kidneys
20% (1L)
3% (1l)
Muscles
15-20% (750-1000ml)
80-85% (20l)
Cardiovascular adaptation resulting from endurance exercise training
CARDIAC HYPERTROPHY: Big and stronger heart. Increased left ventricular contraction force (faster and stronger), increased stroke volume. So, decreased resting and working heart rate.
Increased capillarisation around the lungs and working muscles. More gas exchange can take place, delivering more oxygen.
Increased arterio-venous oxygen difference. There is a large amount of oxygen approaching the muscle at the artery end, but then most of the oxygen diffuses because there is a bigger capillary network so when it gets to the venous end at the aftermath of the muscle there is less oxygen at the venous end. It means that more of the oxygen has diffused into the muscle. Difference in oxygen at the artery when it arrives at the muscle and at the vein as it just leaves the muscle. The bigger the difference in oxygen between those two points, the bigger the offload of oxygen, which means its diffused more into the muscles, therefore more oxygen in the muscles, you can train at a higher intensity or longer or faster.
Maximal oxygen consumption, its variability in selected groups and within different modes of exercise
VO2/MAX: Maximum volume of oxygen consumption. Maximum volume of oxygen that can be consumed at one time. Is a relationship between heart, lungs and muscles to deliver oxygen to your working muscle cells.
Higher VO2 max, longer performance at a higher intensity.
Ml/kg/min.
Vital in distance sports such as cycling, swimming and running.
81ml/kg/min is fitter than a guy with 65 ml/kg/min.
Cross country skiers have the highest VO2 max value, as high as 90 ml/kg/min.
The higher the VO2 max, the fitter, and the highest chance of winning.
Trained vs untrained
Trained people experience more adaptations to the CV system, respiratory system and muscles. Relationships will be stronger and have a higher VO2 max than the untrained.
Male vs female
Male are bigger, have a bigger heart, a bigger respiratory system, bigger muscles with bigger capillary networks. More gas will be exchanged, more can be taken in from the atmosphere and a stronger heart pump to send it around the body. Males tend to have a higher VO2 max because of this difference.
Old vs young
VO2 max decreases - 10 ml/kg/min in 10 years since leaving university.
ELITE performers train hard and are genetically predisposed. Surpasses the non-athlete for a VO2 max and enables them to get a much higher VO2 max.
Running on a treadmill using the big major muscles in legs, torso, core, arms. Weight-bearing exercise. Requires a great deal of oxygen.
Cycle ergometer using the big major muscles in legs. Seated position. Less oxygen required. This does not mean that the VO2 max of elite cyclists is less than the ones of elite runners.
Arm ergometer, steady isokinetic, bicep contraction with a light dumbbell and many reps. Less oxygen required, only works muscles in the arm. Strain less on VO2 max.
Principal structures of the ventilatory system
What takes the air in from the atmosphere is the NASAL CAVITY and the MOUTH. The nasal cavity is the first and primary function for breathing. Takes oxygen from the air. It helps to filter and warm the air as it breathes in. The mouth takes in oxygen from the environment as well.
Both of these cavities are met at the back of the throat, in the PHARYNX. Where the two airways become one. The pharynx then transports the air down to the LARYNX (our voice box + where the EPIGLOTTIS which prevents food and liquid for going down the trachea is), TRACHEA (long thick cartilage rich tube that stays wide open so air can travel through on its journey towards the lungs). At the end of the trachea we branch right and left into each lung. These are called the BRONCHI. The right BRONCHUS and the left BRONCHUS. Bronchi: trunk of a tree.
Inside the lung there are many BRONCHIOLES, at the end of each Bronchi. It increases the surface area massively so oxygen can spread all over the lung.
At the end of the bronchioles there are ALVEOLI (air sacs), an important aspect of the lungs when we talk about gas exchange. This is where it takes place. They are like the leaves of a tree.
At the bottom of the lung, just underneath it, there is a muscle called the DIAPHRAGM. It assists with breathing.
Functions of the conducting airways
Warms and moistens the air: the nose warms and moistens the air so it enters the lungs in a wet state. The lung is wet and moist. No dry gas goes into the lungs.
Lowers air pressure: Air is then funneled into the pharynx and the air pressure is lowered as it goes into the trachea. The low air pressure enables it to enter the lungs in the state that it needs to be.
Protects trachea: Along with the epiglottis, the larynx prevents food and fluid from entering the lungs. When we choke, there is pressure in the epiglottis and it causes us to choke and it temporarily closes the trachea. That is why we feel that we can’t breathe. The epiglottis prevents food and water to go into the trachea and makes sure only pure air gets in there and then to the bronchi and into the lungs.
Pulmonary ventilation
Inflow and outflow of air between the atmosphere and the lungs (breathing)
Total lung capacity
Volume of air in the lungs after a maximum inhalation. Vital capacity + residual volume. Air to breathe and to keep you alive. The total amount of air that the lung can hold.
Vital capacity
Maximum volume of air that can be exhaled after a maximal inhalation. Tidal volume + IRV + ERV. What you need to breathe. Maximal amount of air that can be inhaled and exhaled during a respiratory cycle.
