1.2: Cardiovascular and respiratory systems Flashcards
Pulmonary circuit
circulation of blood through the pulmonary artery to the lungs and pulmonary vein back to the heart
Systemic circuit
circulation of blood through the aorta to the body and vena cava back to the heart
Oxygenated blood
blood saturated with oxygen and nutrients, such as glucose
Deoxygenated blood
blood depleted of oxygen, saturated with carbon dioxide and waste products
Conduction system
a set of structures in the cardiac muscle which create and transmit an electrical impulse, forcing the atria and ventricles to contract
Myogenic
the capacity of the heart to generate its own electrical impulse, which causes the cardiac muscle to contract
Diastole
the relaxation phase of cardiac muscle where chambers fill with blood
Systole
the contraction phase of cardiac muscle where the blood is forcibly ejected into the aorta and pulmonary artery
Heart rate
the number of times the heart beats per minute (resting HR, approximately 72 bpm)
Stroke volume
the volume of blood ejected from the left ventricle per beat (resting SV, approximately 70 ml)
Cardiac output (Q)
the volume of blood ejected from the left ventricle per minute. HR x SV = Q (resting Q, approximately 5 l/min)
Bradycardia
a resting heart rate below 60 bpm
Venous return
the return of blood through the right atria through the veins
Sub-maximal
a low-to-moderate intensity of exercise within a performer’s aerobic capacity
Maximal
a high intensity of exercise above a performer’s aerobic capacity that will induce fatigue
Frank-Starling mechanism (Starling’s law)
increased venous return leads to an increased stroke volume, due to an increased stretch of the ventricle walls and therefore force of contraction
Cardiac Control Centre (CCC)
a control centre in the medulla oblongata responsible for HR regulation
Sympathetic nervous system
part of the autonomic nervous system responsible for increasing HR, specifically during exercise
Parasympathetic nervous system
part of the autonomic nervous system responsible for decreasing HR, specifically during recovery
Vasodilate
widening of arteries, arterioles and pre-capillary sphincters
Vasoconstrict
narrowing of arteries, arterioles and capillary sphincters
Inspiration
drawing of air into the lungs
Expiration
expelling of air from the lungs
Blood pooling
accumulation of blood in the veins due to gravitational pull and lack of venous return
Active recovery
low-intensity activity post exercise to maintain elevated heart and breathing rates
Vascular shunt mechanism
the redistribution of cardiac output around the body from rest to exercise which increases the percentage of blood flow to the skeletal muscles
Arterioles
blood vessels carrying oxygenated blood from the arteries to the capillary beds, which can vasodilate and vasoconstrict to regulate blood flow
Pre-capillary sphincters
rings of smooth muscle at the junction between arterioles and capillaries which can dilate or constrict to control blood flow through the capillary bed
Vasomotor control centre
the control centre in the medulla oblongata responsible for cardiac output distribution
Vasomotor tone
the partial state of smooth muscle constriction in the arterial walls
Alveoli
clusters of tiny air sacs covered in a dense network of capillaries which together serve as the external site for gaseous exchange
Gaseous exchange
the movement of oxygen from the alveoli into the blood stream and carbon dioxide from the blood stream into the alveoli
Haemoglobin
an iron-rich globular protein in red blood cells which can chemically combine with four O2 molecules to form oxyhaemoglobin
Oxygen
the essential gas required for aerobic energy production in the muscle cells
Carbon dioxide
the waste product of aerobic energy production in the muscle cells
Breathing rate
the number of inspirations or expirations (breaths) per minute (resting, approximately 12-15 breaths/min)
Tidal volume
the volume of air inspired or expired per breath (resting, approximately 500ml)
Minute ventilation
the volume of air inspired or expired per minute.
TV x f = VE (resting, approximately 6-7.5 l/min)
Respiratory control centre (RCC)
a control centre in the medulla oblongata responsible for respiratory regulation
Inspiratory centre (IC)
a control centre within the RCC responsible for inspiration
Expiratory centre (EC)
a control centre within the RCC responsible for expiration
Partial pressure
the pressure exerted by an individual gas held in a mixture of gases
Diffusion
the movement of gases across a membrane down a gradient from an area of high pressure (or concentration) to an area of low pressure (or concentration)
Diffusion gradient
the difference in areas of pressure (or concentration) from one side of a membrane to the other
Association
the combining of oxygen with haemoglobin to form oxyhaemoglobin
Dissociation
the release of oxygen from haemoglobin for gaseous exchange
Oxyhaemoglobin dissociation curve
a graph showing the relationship between pO2 and percentage saturation of haemoglobin
Bohr shift
a move in the oxyhaemoglobin dissociation curve to the right caused by increased acidity in the blood stream
