Cardiovascular system Flashcards
Pathway of blood
- Vena cava
- Right atrium
- Tricuspid valve
- Right ventricle
- Semi lunar valve
- Pulmonary artery
- Lungs
- Pulmonary vein
- Left atrium
- Bicuspid valve
- Left ventricle
- Semi lunar valve
- Aorta
- Heart - muscles/ body
Pathway of the Cardiac impulse
- Sinoatrial node (SA node)
- Atrio ventricular node (AV node)
- Bundle of HIS
- Bundle branches
- Perkinje fibres
What is the SA node
The SA node is also known as the pacemaker, located in the right atrium.
What is the AV node
Is an electrical relay situated between the atrium and ventricles.
Describe diastole
When the heart fills with blood while relaxing
Describe systole
When the heart empties while contracting
Stroke volume (SV)
The amount of blood ejected out of the left ventricle per beat.
- Resting - 85ml
- Sub maximal - 160-200ml
- maximal - 160-200ml
Heart rate (HR)
The number of beats per minute.
- resting - 60-80bpm
- sub maximal - 80-120bpm
Cardiac output (Q)
The amount of blood ejected by the left ventricle per minute.
SV X HR = Q
- resting - 5L
- sub max - 15-20L
- max - 30-40L
Chemoreceptors
- detect change in chemicals
Decrease in pH
Increase pp co2
Decrease pp o2
Proprioreceptors
Detects change in heart rate and stroke volume
Baroreceptors
Detects increase in blood pressure and decrease heart rate
Adrenaline
Increases heart rate and stroke volume
Vascular shunt mechanism
The process of redistributing cardiac output
Vascular shunt mechanism
Controlled by the vasomotor centre (VCC). Located in the medulla oblongata, stimulates the SNC to either vaso dilate or constrict the supply of blood to the muscles and organs.
What is venous return
Blood returning to the right side of the heart via the veins
What aids venous return
- muscle pump
- pocket valves
- respiratory pump
- smooth pump
- gravity
What is muscle pump
Muscle contract and pump the blood in the veins back to the heart
What is respiratory pump
Respiratory muscles contract and compress veins
What is pocket valves
Prevent back flow of blood and blood pooling in the veins
What is gravity
Blood that is in the upper region on the body will go back to the heart due to gravity
What is smooth muscle
Surrounds the veins, contracts and pumps blood back to the heart
What is vasoconstriction
The narrowing of the lumen and restricting blood flow
What is vasodilation
The widening of the lumen allowing blood flow
Coronary heart disease (CHD) risk factors
- physical inactivity
- smoking
- obesity
- high blood pressure
- high lipid diet
Cardiovascular drift
The CV drift Is the upward drift of HR overtime, with SV declining and continued maintenance of Q.
Side effects of exercising in warm weather on the cardiovascular system
- increased HR
- plasma volume will decrease due to water loss
- decreased blood volume
- decreased Q
- decreased SV
- decreased blood pressure
Side effects of exercising in warm weather on the respiratory system
- increased mucus production
- constriction on airways
- decreased volume of air
What is blood pressure
The amount of pressure exerted by the blood against the atrial blood vessel walls
