Chapter 3: The Cardiorespiratory System Flashcards
cardiorespiratory system
a system of the body composed of the cardiovascular and respiratory systems
cardiovascular system
a system of the body composed of the heart, blood, and blood vessels
heart
- a hollow muscular organ that pumps a circulation of blood through the body by means of rhythmic contraction
- positioned obliquely in the center of the chest (or thoracic cavity), lying anteriorly (in front) to the spine and posteriorly (behind) to the sternum
mediastinum
the space in the chest between the lungs that contains all the internal organs of the chest except the lungs
sinoatrial (SA) node
a specialized area of cardiac tissue, located in the right atrium of the heart, which initiates the electrical impulses that determine the heart rate; often termed the pacemaker for the heart
atrioventricular (AV) node
a small mass of specialized cardiac muscle fibers, located in the wall of the right atrium of the heart, that receives heartbeat impulses from the sinoatrial node and directs them to the walls of the ventricles
atrium
the superior chamber of the heart that receives blood from the veins and forces it into the ventricles
ventricle
the inferior chamber of the heart that receives blood from its corresponding atrium and, in turn, forces blood into the arteries
stroke volume
- the amount of blood pumped out of the heart with each contraction
- the difference between the ventricular end-diastolic volume (EDV) and the end-systolic volume (ESV)
heart rate (HR)
the rate at which the heart pumps
cardiac output (Q)
- heart rate x stroke volume, the overall performance of the heart
- the volume of blood pumped by the heart per minute (mL blood/min)
blood
- fluid that circulates in the heart, arteries, capillaries, and veins, carries nutrients and oxygen to all parts of the body, and also rids the body of waste products
- consists of cells suspended in a watery liquid called plasma that also contains nutrients such as glucose, hormones, and clotting agents
blood vessels
network of hollow tubes that circulates blood throughout the body
arteries
vessels that transport blood away from the heart
capillaries
- the smallest blood vessels, and the site of exchange of chemicals and water between the blood and the tissues
- connect venules with arterioles
veins
vessel that transport blood from the capillaries toward the heart
arterioles
small terminal branches of an artery, which end in capillaries
venules
the very small veins that connect capillaries to the larger veins
respiratory system
- a system of organs (the lungs and respiratory passageways) that collects oxygen from the external environment and transports it to the bloodstream
- includes the trachea, bronchi, alveoli, and the lungs
respiratory pump
is composed of skeletal structures (bones) and soft tissues (muscles) that work together to allow proper respiratory mechanics to occur and help pump blood back to the heart during inspiration
inspiration
the process of actively contracting the inspiratory muscles to move air into the body (inhalation)
expiration
the process of actively or passively relaxing the inspiratory muscles to move air out of the body (exhalation)
diffusion
the process of getting oxygen from the environment to the tissues of the body
maximal oxygen consumption (VO2 max)
the highest rate of oxygen transport and utilization achieved at maximal physical exertion
approximate size of adult heart
- size of a typical adult fist
- weighs roughly 300g or 10 ounces
what type of muscle is cardiac muscle?
involuntary (cannot typically be consciously controlled)
characteristics of cardiac muscle fibers
- shorter and more tightly connected than skeletal muscle
- irregularly spaced dark bands between cardiac cells called intercalated discs
intercalated discs
- irregularly spaced dark bands between cardiac cells
- help hold muscle cells together during contraction
- create an electrical connection between the cells that allows the heart to contract as one functional unit
typical resting heart rate
70-80 beats per minute
interatrial septum
separates the atria
interventricular septum
separates the ventricles
right side of the heart
- pulmonic side
- receives blood from the body that is low in O2 and high in CO2 (deoxygenated) and pumps it to the lungs and then back to the left atria
left side of the heart
- systemic side
- pumps blood high in O2 and low in CO2 (oxygenated) to the rest of the body
right atrium
gathers deoxygenated blood returning to the heart from the entire body
left atrium
gathers oxygenated blood coming to the heart from the lungs
right ventricle
- thin walls
- pumps under low pressure because it only has to pump blood a short distance (to the lungs)
- receives the deoxygenated blood from the right atrium and then pumps it to the lungs to be saturated with incoming oxygen
left ventricle
- thicker walls
- pumps under high pressure because it pumps blood out to the rest of the body
- receives oxygenated blood from the left atrium and proceeds to pump it to the entire body
how is each chamber of the heart separated?
- via valves
- prevents a backflow or spillage of blood back into the chambers
- these valves include the atrioventricular valves (tricuspid and mitral) and the semilunar valves (pulmonary and aortic)
end-diastolic volume (EDV)
- the filled volume of the ventricle before contraction
- typically about 120mL of blood
end-systolic volume (ESV)
- the residual volume of blood remaining in the ventricle after ejection
- typically above 50mL of blood
how to manually monitor heart rate
- place the index and middle fingers around the palm side of the wrist
- locate the artery by feeling for a pulse and apply light pressure
- during rest: count the number of beats in 60 seconds
- during exercise: count the number of beats in 6 seconds and add a zero to that number
3 kinds of cells in the blood
- red blood cells
- white blood cells
- platelets
red blood cells
carry oxygen from the lungs throughout the body
white blood cells
help fight infection
platelets
help with clotting
how much of the blood is made of plasma?
55% (remaining 45% made up of blood cells)
how much blood does the average adult have?
4-6 L
blood: transportation
- transports oxygen and nutrients to tissues
- transports waste products from tissues
- transports hormones to organs and tissues
- carries heat throughout the body
blood: regulation
-regulates body temperature and acid balance in the body
blood: protection
- protects the body from excessive bleeding by clotting
- contains specialized immune cells to help fight disease and sickness
3 major types of blood vessels
- arteries
- capillaries
- veins
aorta
- largest artery in the body
- carries blood away from the heart
role of the respiratory system
- works intimately with the cardiovascular system to accomplish optimal cellular function by transporting oxygen from the environment and transferring it to the bloodstream, and transferring carbon dioxide from the blood to the lungs and eventually transporting it to the environment
- this entire process is accomplished through the integrated functioning of the respiratory pump to move air in and out of the body and the respiratory passageways to channel the air
breathing (or ventilation)
- the actual process of moving air in and out of the body
- requires optimal functioning of the respiratory pump and all of its components
inspiratory ventilation
- active
- requires active contraction of inspiratory muscles to increase the thoracic cavity volume, which decreases the intrapulmonary pressure (or pressure within the thoracic cavity)
- when the intrapulmonary pressure decreases below that of the atmospheric pressure, air is drawn into the lungs
two forms of inspiratory ventilation
- normal resting state (quiet) breathing
2. heavy (deep, forced) breathing
normal resting state (quiet) breathing
requires the use of the primary respiratory muscles (i.e., diaphragm, external intercostals)
heavy (deep, forced) breathing
requires the additional use of the secondary respiratory muscles (scalenes, pectoralis minor)
expiratory ventilation
- can be both active and passive
- during normal breathing, it is passive as it results from the relaxation of the contracting inspiratory muscles
- during heavy breathing, it relies on the activity of expiratory muscles to compress the thoracic cavity and force air out
what happens to intrathoracic pressure during inspiration?
it decreases, causing a drop in pressure in the right atrium of the heart, and helps improve blood flow back to the heart
2 categories of respiratory passages
- conducting airways
2. respiratory airways
conducting airways
- consist of all the structures that air travels through before entering the respiratory airways
- the nasal and oral cavities, mouth, pharynx, larynx, and bronchioles provide a gathering station for air and oxygen to be directed into the body
- these structures also allow the incoming air to be purified, humidified, and warmed or cooled to match body temperature
respiratory airways
- collect the channeled air coming from the conducting airways
- at the end of the bronchioles sit the alveoli, which are made up of clusters of alveolar sacs, where gases such as O2 and CO2 are transported in and out of the bloodstream via diffusion
role of the cardiorespiratory system in the human movement system
- provide many essential elements (such as oxygen)
- remove waste product that can cause dysfunction in the body
oxygen uptake / consumption
- the use of oxygen by the body
- VO2
resting oxygen consumption (VO2)
- approximately 3.5 mL of oxygen per kilogram of body weight per minute
- typically termed 1 metabolic equivalent or 1 MET
- calculated as follows: VO2 = Q x a - vo2 (Fick equation)
what is the best measure of cardiorespiratory fitness?
maximal oxygen consumption (VO2max)
how to determine VO2 max?
- directly measure ventilation, oxygen consumption, and carbon dioxide production during a maximal exercise test
- expensive and not readily available (preferred method is to estimate from a submaximal exercise test)
tests that can be used to predict VO2 max
- Rockport Walk Test
- Step Test
- YMCA bike protocol test
abnormal breathing patterns associated with stress and anxiety
- breathing becomes more shallow, using the secondary respiratory muscles more predominantly than the diaphragm
- increased respiratory muscle activity and excessive tension may result in headaches, lightheadedness, and dizziness , and negatively impact posture
- excessive breathing can lead to altered CO2 and O3 content and can lead to feelings of anxiety that further initiate an excessive breathing response
- inadequate oxygen and retention of metabolic waste within muscles can create fatigued, stiff muscles
- inadequate joint motion of the spine and rib cage, as a result of improper breathing, causes joints to become restricted and strict
results of abnormal breathing patterns
decreased functional capacity that may result in headaches, feelings of anxiety, fatigue, poor sleep patterns, and poor circulation
