Cardiovascular and respiratory systems Flashcards
Pulmonary circuit
circulation of blood through the pulmonary arteries to the lungs and pulmonary veins back to the heart
Systemic circuit
circulation of blood through the aorta to the body and vena cavae back to the heart
SA node
generates electrical impulses, causing atria walls to contract.
Bundle of His
located in the septum, this splits the impulse in two, ready to be distributed to the ventricles
AV node
this collects the impulses and delays it by 0.1 seconds to allow the atria to finish contracting
Bundle branches
carry the impulse to the base of each ventricle
Purkinje fibres
distribute the impulse through the ventricles walls, causing them to contract
Diastole
the relaxation phase of cardiac muscle where chambers fill with blood
- low pressure
- Av valves open
- semilunar valves are closed
Systole
the contraction phase of cardiac muscle where blood is forcibly ejected into the aorta and pulmonary artery
Atrial Systole
atria contact, forcing blood into the ventricles
Ventricular systole
ventricles and AV valves close/contract, blood is pushed out of the ventricles leaving the heart
Stroke volume
amount of blood ejected from the left ventricle per beat
Cardiac output
amount of blood ejected from the left ventricle per minute
Venous return
the return of the blood to the right atrium through the veins
Frank-Starling mechanism
increased venous return leads to increased SV, due to an increased stretch of the ventricular walls and therefore force of contraction
Cardiac control centre
a control centre in the medulla oblongata responsible for HR regulation
Sympathetic nervous system
part of the autonomic system responsible for increasing HR, specifically during exercise
Parasympathetic nervous system
part of the autonomic system responsible for decreasing HR, specifically during recovery
Proprioceptors
in muscles, tendons and joints, these inform the CCC that movement had increased
Chemoreceptors
located in the aorta and carotid arteries, these detect a decrease in blood pH due to an increase of lactic acid
Baroreceptors
located in blood vessel walls, these inform the CCC of increased blood pressure
Arteries and arterioles
carry oxygenated blood from the heart to muscles and organs
Capillaries
gas exchange takes place
Veins and venules
carry deoxygenated blood from the muscles and organs back to the heart
Venous return mechanisms
pocket valves smooth muscle gravity muscle pump respiratory pump
Vasodilation
widening of arteries, arterioles and pre-capillary sphincters
Vasoconstriction
narrowing of arteries, arterioles and pre-capillary sphincters
Venodilation
widening of the veins and venules
Venoconstriction
narrowing of the veins and venules
Vascular shunt mechanism
the redistribution of cardiac output around the body from rest to exercise which increases the % of blood flow tot he skeletal muscles
Pre-capillary sphincter
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
located in the medulla oblongata responsible for cardiac output distribution
Gaseous exchange
the movement of O2 from the alveoli into the blood stream and CO2 from the blood stream into the alveoli
Pulmonary ventilation
breathing of air into and out of the lungs
Breathing rate
the number of inspirations or expirations per minute
Tidal volume
the volume of air inspired or expired per breathe
Minute ventilation
the volume of air inspired or expired per minute
External intercoastal muscles inspiration rest
contract pulling chest walls up and out during rest
External intercoastal muscles expiration rest
relax so that the chest walls move in and down
Internal intercoastal muscles expiration exercise
contract and pull ribs down and in
Diffusion gradient
difference between high and low pressure
Oxyhaemoglobin dissociation curve
a graph showing the relationship between pO2 and % saturation of haemoglobin
Bohr Shift
a move in the oxyhaemoglobin dissociation curve to the right caused by increased acidity in the blood stream
Effects of Bohr Shift
increased blood and muscle temperature
increased pp of CO2
increased production of lactic acid and carbonic acid