Essentials of Exercise: Chapter 5 - Physiology of Training Flashcards
To meet the increaseed demands of muscle during exercise, what two major adjustments in blood flow mus occur?
Increase in Cardiac Output and a redistribution of blood from inactive organs to the active skeletal muscle.
Cardiac Output
The amount of blood pumped by the heart per minute; usually expressed in liters of blood per minute.
Heart Rate (HR)
The number of heart beats per minute.
Stroke Volume (SV)
The amount of blood pumped from the left ventricle of the heart with each beat.
What is the equation for Cardiac Output
Heart Rate x Stroke Volume
Sinoatrial Node (SA node)
A group of specialized myocardial cells, located in the wall of the right atrium, that controls the heart’s rate of contraction; the “pacemaker” of the heart.
What are the two most prominent factors that influence heart rate?
The parasympathetic and sympathetic divisions of the autonomic nervous system.
Autonomic Nervous System
The part of the nervous system that regulates involuntary body functions, including the activity of the cardiac muscle, smooth muscles, and glands.
Depolarize
To decrease decrease the electrical potential across a membrane, as when the inside of a neuron becomes less negative to the outside.
Repolarize
To restore the difference in charge between the inside and outside of the plasma membrane of the muscle fiber or cell following depolarization.
Atrioventricular Node (AV node)
The specialized mass of conducting cells in the heart located at the atrioventricular junction.
Vagus Nerves
The tenth cranial nerve; parasympathetic, general sensory nerve.
Acetylcholine
A white crystalline neurotransmitter and derivative of choline that is released at the ends of nerve fibers in the somatic and parasympathetic nervous systems and is involved in the transmission of nerve impulses in the body.
Cardiac Accelerator Nerves
Part of the sympathetic nervous system that stimulates the SA node to increase heart rate.
Catecholamine
Hormone (e.g., epinephrine and nor-epinephrine) released as part of the sympathetic response to exercise.
Epinephrine
A hormone released as part of the sympathetic response to exercise; also called adrenaline.
Norepinephrine
A hormone release as part of the sympathetic response to exercise.
Diastolic Blood Pressure (DBP)
The pressure in the arteries during the relaxation phase of the cardiac cycle; indicative of total peripheral resistance.
Diastole
The period of filling of the heart between contractions; resting phase of the heart.
Frank-Starling Mechanism
The mechanism by which an increased amount of blood in the ventricle places a stretch on the cardiac muscle fibers, thereby causing a stringer ventricular contraction to increase the amount of blood ejected.
Vasoconstriction
Narrowing of the opening of blood vessels (notably the smaller arterioles) caused by contraction of the smooth muscle lining the vessels.
Vasodialation
Increase in diameter of the blood vessels, especially dilation of arterioles leading to increased blood flow to a part of the body.
Autoregulation
Local control of blood distribution (through validation) in response to a tissue’s changing metabolic needs.
Viscera
The collective internal organs of the abdominal cavity.
Parasympathetic Nervous System
A subdivision of the autonomic nervous system that is involved in regulating the routine functions of the body, such as heart beat, digestion, and sleeping.
Stimulates digestive secretions, slows the heart, constricts the pupils, dilates blood vessels.
Sympathetic Nervous System
Responsible for mobilizing the body’s energy and resources during times of stress and arousal.
Reduces digestive secretions, speeds the heart, contracts blood vessels.
Systolic Blood Pressure (SBP)
The pressure exerted by the blood on the vessel walls during ventricular contraction.
What factors contribute to Systolic Blood Pressure increase during exercise?
- Increased heart contractility and stroke volume increase the force with which blood leaves the heart.
- Muscle action requires greater force or pressure to deliver blood into the exercising muscles.
- Vasodilation within the exercising muscles allows more blood to drain from the arteries through the arterioles and into the muscle capillaries, thus minimizing changes in diastolic pressure.
