Sports science - circulatory responses to exercise Flashcards
What is the functions of the CV system?
- delivery
- removal
- transport
- maintenance
- protection (white blood cells)
Is the CV system and open loop or closed loop system?
closed
What are the components of the CV system?
- a fluid medium - BLOOD
- a system of channels - BLOOD VESSELS
- a pump - HEART
What component of blood can you measure hydration by?
plasma
What are the 2 main components of blood?
- plasma (55%)
- formed elements (45%)
What is plasma made up of?
- water (90%)
- plasma proteins (7%)
- other (3%)
What is the formed elements made up of?
- red blood cells (99%)
- white blood cells + platelets (1%)
Does plasma volume increase or decrease after endurance training?
increase
Does red blood cell volume increase or decrease after endurance training?
decrease
Why does more plasma lead to easier blood flow?
- less viscous
- less resistant to flow
What does the vascular system consist of?
- brain
- lungs
- heart
- arteries
- veins
- arterioles
- capillaries
What is the role of arterioles?
determine blood flow to individual organs
What is the importance of arterioles?
the redistribution of blood flow with exercise
What type of vessels can arterioles be referred as?
resistance
What type of vessels can the venous system be referred as?
capacitance
What is venous pooling?
trouble with getting blood to the brain due to hydrostatic pressure
Is blood in the venous system at high or low pressure?
low
What is the role of a muscle pump?
- contraction of muscles pushes blood up the veins
- forces blood back to the heart under pressure
How many pumps does the heart consist of?
2
What are the names of the 2 heart pumps?
- pulmonary (right)
- systemic (left)
List the roles of arteries and arterioles
- carry blood away from the heart
- determine redistribution of blood flow during exercise
What is the role of capillaries?
exchange of oxygen and carbon dioxide and nutrients within tissues
List the roles of veins and venules
- carry blood towards the heart
- skeletal muscle pump, increases the amount of venous blood returning to the heart during exercise
How do you calculate cardiac output (Q)
Q = heart rate (HR) x stroke volume (SV)
What are the 2 nervous systems?
- parasympathetic
- sympathetic
What is the role of the parasympathetic nervous system?
slows HR by inhibiting sinoatrial (SA) and atrioventricular (AV) node
What is the role of the sympathetic nervous system?
increases HR by stimulating SA and AV node
What factors affect stroke volume (SV)?
- increase force of contraction = increased SV
- increase sympathetic nervous system activation
. effects of circulating adrenaline and noradrenaline
. direct stimulation of the heart muscle - increase end diastolic volume (EDV)
. length-tension relationship
. increase EDV = increased stretch of ventricular sarcomeres
. increase stretch = increased force of contraction
What are the major factors affecting EDV?
- increased activity of sympathetic nerves to veins
- increased blood volume
- increased skeletal muscle pump
- increased inspiration movements
What does cardiac output increase due to?
- increased HR
- increased SV
Why does oxygen delivery to exercising skeletal muscle increase?
- increased cardiac output
- redistribution of blood flow from inactive organs to the contracting skeletal muscle
Why does cardiac output increase as a linear function of oxygen during exercise?
- stroke volume reaches a plateau at approximately 40% of VO2 max
- at work rates above 40% VO2 max, the rise in cardiac output is due to increase in HR alone
