Vascular Shunt Mechanism Flashcards
What does ‘Q’ mean?
Distribution of cardiac output
During exercise what does the cv do?
Distributes the blood to the working muscles during exercise
At rest how much blood each
Muscles-20%
Organs-80%
Where and how much blood goes to body?
80% is supplied to muscles
20%- organs (mainly brain as it needs to control muscle actions that are being produced)
What does the vaso control centre control?
The Vascular Shunt Mechanism
What’s the role of chemoreceptors?
Inform the brain thst the lactic acid has increased and co2 levels. Oxygen levels have decreased (chemical changes)
What’s the role of the Bororeceptors?
Informs the brain that systolic blood pressure levels have increased
What are veins?
Blood vessels that carry the blood to the heart
Arteries?
Blood flowing from the heart
Where does superior vena cava receive blood from?
Receives blood from the head, neck and chest
Where does the inferior vena cava receive blood from?
Receives blood from the trunk and lower limbs
What is the role of valves?
To prevent blood back flow
Which valve is in the right atrium?
Tricuspid valve
What is the vascular control centre?
The vcc controls the vascular shunt mechanism
What is the role of the sympathetic nervous system?
Increases the sympathetic nerve information, vasoconstrictor arterioles to organs to reduce the amount of blood going to them and vasodilation to the muscles to receive more blood during exercise
What is venous return?
Basically veins that carry blood back to the heart, during exercise venous return is massive.
What is the disadvantage of venous return?
Gravity always tries to pull blood down, this is why pocket valves are in use to reduce this from happening.
What is the muscle pump mechanism?
During rest, veins travel in between muscle groups, when muscle is relaxed vein is open and blood will collect.
During exercise- when muscles contract, muscles bulge out and squeeze the vein which will squeeze the blood back to the heart
What happens when theres more contractions?
Increases pressure
What is blood poling?
VR requires a force to push blood back to the heart, if no pressure blood will sit in pocket valves (heavy legs) Good for cool down
How is Sv increased?
During exercise theres a greater q because the athlete requires more blood and oxygen to be required to the muscles, increase In blood helps to remove lactic acid etc. Heart beats faster during exercise so more waste products get out of body.
What happens during diastole?
Heart relaxes, fills with blood. Blood pressure decreases.
What happens during systole?
Heart pushes blood around the body during systole and pressure increases
What is SV?
The volume of blood pumped out of the heart per beat
What is Hr?
The number of beats per minute
What is starlings law?
Venous return increases, End of volume of diastole increases, stretch increases, recoil increases, force increases and sv increases= Q
What is determined by VR
SV (starlings ;aw)
What is the equation that links q, hr and sv
Q= HR X SV
What does the sympathetic nervous system do?
Increases HR and force of contraction, stimulates SA node to increase HR and SV which means and increase Iin Q
What does the parasympathetic nervous system do?
Vagus stimulates the SA node, to reduce HR and SV which decreases Q
What side is does
right
what side is ox
left
Whats the job of the atria?
Where the blood enters
what is the job of the ventricles
where the blood exits
What is the route of the blood
Superior vena cava- inf VC- deox enters RA- Through tricuspid valve into RV- Deox pumped through pul arteries- lungs (semi lunar prevents blood entering the heart)- Blood is oxygenated at the lungs- Oxgenated blood returns back to the heart through pul veins- ox enters L Chamber- Bicuspid valve into LV- ox blood passed through aorta into muscles and organs
What are the properties of arteries?
Thick muscular walls, bp is high
what is the vascular shunt?
Redistribution of Q during exercise.
VCC controls the vascular shunt
What are arterioles?
Arteries that carry ox blood to muscles and organs with a middle layer that can vaso constrict, vaso dilate
What is the respiratory pump?
Breathing increases during exercise Pressure changes in thorax and abdomen, squeezes large veins back to the heart
what is smooth muscle?
Contraction/relaxation of smooth muscle in middle layer of vein walls help push blood through veins towards the heart.
What is vR?
The transport of blood from the capillaries through the venues, veins back tot he ra of the heart
At rest how is VR maintained?
Maintained by blood pressure and structure of veins
During excise how is VR maintained?
Pressure of blood in veins is too low to maintain VR, sv and q decreases. Body needs support to pus blood against gravity through veins- increase vr and sv (5 mechanism)
What is the resting sv?
70ml
What is the anticipatory rise during intensities?
Body prepares to be active- oxygen is available for working muscles
What is the plateau during the intensity fo workout graph?
Hr matches oxygen demands of muscles
What is the after exercise graph and why plateau decreases>
Waste products are removed, oxygen debt is repaid from beginning
Why is a large venous return needed fro high intensity exercise?
Stroke volume increases if venous return increases an increase in venous return means the ventricles stretch further before contracting forcing more blood out of heart- starlings law
Why is a large venous return needed fro high intensity exercise?
Stroke volume increases if venous return increases an increase in venous return means the ventricles stretch further before contracting forcing more blood out of heart- starlings law
What do the pre capillary sphincters control?
Blood flowing to the capillaries, they are smooth muscle surrounding the intersection between the capillaries and arterioles
What are the neural factors for heart rate?
Baro- blood
Prop-muscle
Them- acidity
What are the hormonal factors of heart rate?
Adrenaline- increases hr by stimulating adrengeic receptors and sa node
Noradrenaline- Released in stressful situations to increases hr and prepare body
What are the intisinc factors of heart rate?
Temperature, increasing temperature increase heart rate to increase blood flow to skin where heat is lost
How is athletes blood redistributed before exercise?
anticipatory rise, working muscles store up oxygen- venous return muscle pump, sympathetic
