Fitness Theory Chap 6: Cardiorespiratory System Physiology Flashcards
What are the three components of the cardiorespiratory system?
the heart, the lungs, and the blood vessels
Name the three types of blood vessels
arteries, veins, and capillaries
What are the significant functions of the cardiorespiratory system?
- transport oxygen and other nutrients to the cells of the body
- transport carbon dioxide and other by-products away from the cells to the lungs
- regulate body temperature (thermoregulation)
- regulate the levels of fluid in the body cells and blood (important for efficient function)
- exchange oxygen and carbon dioxide at the lungs and at the tissue sites (alveoli and muscle cell)
What causes a heart murmur?
when the valves do not completely close between beats there is a mixing or ‘back flow’ of blood
What is pulmonary circulation?
the circulation of blood between your heart and lungs
process: blood is pumped from the RV through the pulmonary semilunar valve to the lungs by way of pulmonary arteries. In the lungs, exchange of oxygen and carbon dioxide takes place, and the blood, now rich in oxygen, flows back to the LA through the pulmonary veins
What is systemic circulation?
the circulation of blood between the heart and the rest of the body
process: blood that has returned to the LA flows into the LV through the left AV valve, and is then pumped out through the aortic semilunar valve into the aorta. From the aorta, blood continues into the arteries and finally into the capillaries
What are capillaries?
thin-walled blood vessels in active tissue that allow oxygen and carbon dioxide to flow in and out very easily (capillaries surround the alveoli and receive oxygen from the alveoli and deliver it into the red blood cells)
What are arteries?
thick-walled, and carry richly oxygenated blood away from the heart
What are veins?
thin-walled, have one-way valves, and carry poorly oxygenated blood back to the heart
Explain cardiac output (Q)
the amount of blood pumped out by each side of the heart in one minute. Cardiac output is a combination of heart rate (HR) and stroke volume (SV)
Define heart rate (HR)
the number of beats per minute
Define stroke volume (SV)
the volume of blood pumped by the ventricle each beat (average stroke volume for a male is 70-75 ml of blood per beat and females about 65-70 ml/beat)
Define blood pressure
the pressure exerted by blood against the walls of the large arteries in the systemic circulation system
What is the normal blood pressure range?
110-120/70-80 mm Hg
What is systolic pressure?
the pressure in the arteries when the heart is contracting and forcing blood out
What is diastolic pressure?
the pressure in the arteries when the heart is in between beats and filling up with blood
List some factors that affect blood pressure
- narrowing of the arteries (e.g. from plaque or stress)
- increased thickness of the blood (e.g. from dehydration)
- body position (e.g. declined position as when performing a bench press)
- age
- kidney function ( by allowing more or less water to leave the body through urine, the volume of blood and blood pressure can change)
- excessive salt in the diet
What is hypotension?
defined as low blood pressure when ‘systolic’ is less than 100 mm Hg
What is hypertension?
defined as high blood pressure when readings are 140/90 (borderline hypertension) or greater
What is venous pooling?
veins do not have smooth muscle and as a result, cannot assist in maintaining blood pressure or in returning blood to the heart. Therefore, if someone stands for a long period of time or sits down right after exercise, the blood can pool in the veins of the lower body. This can decrease the blood returning to the heart and cause blood pressure to drop
What are the components of the respiratory system?
- nose
- pharynx (throat)
- trachea (wind pipe)
- bronchi (conducting tubes of oxygen)
- lungs and alveoli (sites of exchange of oxygen and carbon dioxide)
Explain pulmonary ventilation
air from the environment moves into the nose and mouth and travels into the pharynx, trachea and bronchi where it is warmed, cleaned and moistened
Explain external respiration
oxygen in the lungs diffuses into the blood and carbon dioxide (a waste product of cell activity) in the blood moves into the lungs where it can be exhaled. The alveoli are the sites of external respiration
What are alveoli?
grape-like clusters of elastic hollow sacs. They represent the last stop for air coming into the lungs before oxygen moves into the blood
Where are the sites of gas exchange (oxygen and carbon dioxide)?
at the alveoli, capillary beds, and muscle cell
What is hemoglobin?
an oxygen-carrying protein that exists inside the red blood cells of the human body. Hemoglobin has oxygen and carbon dioxide binding sites and releases oxygen to cells as it travels through the blood stream
What is the Haldane effect?
carbon dioxide is more readily dissolved in deoxygenated blood, facilitating its removal from the body after the oxygen has been released to tissues undergoing metabolism
Define ventilation rate
the number of breaths an individual takes per minute
What is tidal volume?
the amount of air taken in during normal inspiration or expiration (around 600 ml for males and 500 ml for females)
What is total lung capacity (TLC)?
maximum inspiration volume (normal value for males is 6L and for females is 4-5L. For elite athletes in aerobic sports, 7-8L)
What is maximal oxygen consumption (maxVO2)?
the maximal amount of oxygen that is delivered to, and is used (consumed) by muscles
What is maximum heart rate (MHR)?
the uppermost limits of your pulse per minute. Can be determined by this equation:
220 - age = MHR
What is the formula used to determine the upper and lower limits of your target heart rate (THR) during aerobic exercise?
MHR x the desired % of intensity for the upper and lower limits according to the client’s goal
e.g. 40 year old male
MHR = 220 - 40 = 180
THR upper limit of training = 180 x 0.85 = 153 BPM
THR lower limit of training = 180 x 0.70 = 126 BPM
What is the average resting heart rate (RHR)?
between 60-80 beats per minute
Exercise requires the body to redirect a greater percentage of the cardiac output to the exercising muscles. At rest, what percentage of the cardiac output goes to the muscles? What percentage during an all-out exhaustive exercise?
at rest: about 15%
during all-out exhaustive exercise: 80%
What is the arterial-venous oxygen difference?
the difference in the amount of oxygen in arterial blood (blood rich in oxygen leaving the heart), and venous blood (blood returning to the heart after oxygen has left and gone into the muscles)
Define hyperventilation
respiration beyond what is necessary to meet the needs of the body
What is dyspnea?
shortness of breath often experienced during exercise by beginners exercising too hard
The Valsalva Maneuver is the result of what three factors?
- forceful contraction of the abdominal muscles and diaphragm
- forceful contraction of the muscles of the chest cavity
- closed epiglottis (covers the windpipe or trachea)
What is the Valsalva Maneuver?
when the large veins in the abdominal and chest cavity are compressed and blood return to the heart is reduced
Explain the difference between the cardiovascular system and the respiratory system
cardiovascular system: carries oxygen in the blood through the heart and blood vessels
respiratory system: responsible for getting oxygen into the body, filtering, warming and moisturizing the air, and exchanging oxygen and carbon dioxide at the lungs and capillary networks
During exercise, a ‘steady state’ occurs when. . .
the oxygen supply requirement meets the oxygen demand of the body
Oxygen transport and utilization: once air flows into the alveoli of the lungs, the oxygen moves into the alveolar capillaries, and is transported in the blood through the circulation system. Describe the four ways this occurs
- oxyhemoglobin: oxygen binds to an iron-protein compound inside red blood cells to form oxyhemoglobin
- in fluid or the blood (plasma): a small amount of oxygen can travel freely through plasma
- exercise, high altitude, and a change in body temperature: can affect how much oxygen is bound to hemoglobin
- maximal oxygen consumption (maxVO2)
What is internal respiration?
oxygen that has traveled in the blood to body cells moves into the cells and carbon dioxide moves from the cells into the blood. The oxygen, now in the cells, can be used for energy production (cellular respiration)
During rest, when the body does not need large amounts of oxygen, how many ml of oxygen leave the alveoli each minute and go into the blood? How many ml of carbon dioxide move from the blood into the lungs?
200-250 ml of oxygen
175-200 ml of carbon dioxide
What is the cardiac output at rest? During exercise?
5-6 L/min at rest
20-40 L/min during exercise
What are some of the reasons given to explain the ‘second wind’ individuals often experience during exercise?
- the respiratory system, including breathing muscles, has adjusted to the workload and is in a comfortable steady state
- any lactic acid that accumulated in the blood at the start of exercise has been removed and aerobic energy systems are working at peak efficiency
- chemicals (endorphins) produced by the brain act as natural painkillers during exercise
- psychological factors including stress reduction and enjoyment of the exercise
