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