the heart Flashcards
what is myogenic
Myogenic is the capacity of the heart to generate its own impulses at rest.
whats the Sympathetic system
A part of the automatic nervous system that speeds up heart rate
whats the Parasympathetic system
A part of the automatic nervous system that decreases heart rate.
what is Medulla oblongata
The most important part of the brain as it regulates processes that keep us alive as breathing and heart rate.
what are Chemoreceptors
Tiny structures in the carotid arteries and aortic arch that detect changes in blood acidity caused by an increase or decrease in the concentration of carbon dioxide.
what are Baroreceptors
Special sensors in tissues in the aortic arch, carotid sinus, heart and pulmonary vessels that respond to changes in blood pressure to either increase or decreases heart rate.
what are Proprioceptors
Sensory nerve endings in the muscles, tendons and joints that detect changes in muscle movements
whats Adrenaline
A stress hormone that is released by the sympathetic nerves and cardiac nerve during exercise which causes an increase in heart rate.
whats Stroke volume
The volume of blood pumped out by the heart ventricles in each contraction.
whats the Diastole phase
When the heart relaxes to fill with blood.
whats the Ejection fraction
The percentage of blood pumped out by the left ventricle per beat.
what do the Mechanoreceptors do
detect muscle contraction
stroke volume
the volume of blood pumped out by the heart ventricles in each contraction
heart rate
The number of times the heart beats per minute
Cardiac output
The volume of blood pumped out by the heart ventricles per minute
Ejection fraction
The percentage of the blood pumped out by the left ventricle per beat
whats cardiovascular drift
the progressive increase in heart rate and decrease in stroke volume that begins after approximately 10 min of prolonged moderate-intensity exercise
factors in cardiovascular drift
starts after ten mins
heart/pulse rate increases
decrease in stroke volume / ejection fraction
fluid lost as sweat
plasma is reduced
reduced venous return
starlings law
cardiac output increase due to more energy to cool the body
what is starlings law
the stroke volume of the left ventricle will increase as the left ventricular volume increases due to the myocyte stretch causing a more forceful systolic contraction.
starlings law how it works
Increased venous return —> greater diastolic filling of the heart —> cardiac muscle stretched —> more force of contraction —> increased ejection fraction
what are pukinje fibres
specialised cardiac tissue which spreads a cardiac impulse throughout the myocardium, causing the ventricles to contact
whats the sinoatrial node (SAN)
a mass of specialised cardiac muscle fibres located in the right atrium responsible for emitting the cardiac impulse. also known as the pacemaker of the heart
whats the atrioventricular node
a mass of conducting cells located in the right atrial wall which acts as a distributor passing the cardiac impulse down through the septum
whats bundle of HIS
two branches of the conduction system of the heart that run down the entire length of the septum
