vascular system Flashcards
What is the pulmonary system
takes deoxygenated blood from the heart to the lungs and oxygenated blood back to the heart
what is the systemic system
takes oxygenated blood to the body from the heart and then the return of deoxygenated blood from the body to the heart
what are the 5 different blood vessels in the body
Heart -> Arteries -> arterioles -> capillaries -> venules -> veins -> heart
how do you work out blood pressure
blood pressure = blood flow x resistance
what is systolic pressure
this is where the heart contracts - blood is forced out under high pressure
what is diastolic pressure
where the ventricles relax and lower pressure
how do you measure blood pressure
12o mmHg / 80 = milimetres of mercury
what happens if the pressure in the lungs is low?
this makes it hard to return blood to the heart. the larger lumen offers little resistance to blood flow.
what mechanics are needed if pressure in the veins is low
The skeletal muscle pump
the respiratory pump
pocket valves
what is the skeletal muscle pump
muscles contracting and relaxing pressing on nearby veins causing a pumping effect. this squeezes the blood back to the heart
what is the respiratory pump
when muscles contract during breathing in and out pressure changes occur in the thoracic and abdominal cavities. this compresses nearby veins and assists blood flowing back.
what are pocket valves
it is important that blood in veins only flows in one direction. valves ensure this happens. They close once blood has passed through to prevent blood from flowing back.
what are other factors thatr aid venous return
very thin layer of smooth muscle on vein walls, which help to squeeze blood back into the heart.
gravity helps blood from the upper body return to the heart
the suction pump action of the heart
what is the equation of venous return
venous pressure - right atrial pressure / venous vascular resistance
How is oxygen transported transported by
During exercise, oxygen diffuses into the capillaries to serve the skeletal muscles.
3% dissolves into the plasma, 97% combines with haemoglobin to form oxyhaemoglobin.
when fully saturated haemoglobin will carry oxygen molecules.
this happens when partial pressure of oxygen in the blood is high
At the tissues, oxygen is released from the oxyhaemoglobin due to lower pressure of oxygen in the tissues - this is known as oxygen dissociation
In the muscle oxygen is stored in the mitochondria until it is used by the muscles
mitochondria are the centres in the muscles where aerobic respiration takes place.
what happens to the oxyhaemoglobin dissociation curve.
what is the Bohr shift
Durine exercise, the s-shaped curve shifts to the right because when muscles require more oxygen, the dissociation of oxygen from haemoglobin in the blood capillaries to the muscle tissues occur more efficently - this is known as Bohr shift
what are three factors are responsible for the Bohr shift
increase in blood temperature
partial pressure of carbon dioxide increases
PH - more carbon dioxide lower blood PH
Redistribution of blood?
what happens if you eat a meal before a competition?
a full gut would result in more blood being directed to the stomach.
less blood being redirected to the working muscles
detrimental affect on performance as less oxygen is available
where is the vasomotor centre located and what does it control
the vasomoter is found in the medulla oblongata of the brainand helps to control both blood pressure and blood flow.
what doe chemoreceptors do?
they detect chemical changes e.g increased carbon dioxide and lactic acid. they send a signal to the vasomotor centre which redistributes blood to flow through
what happens when sympathetic stilumation increases
vasoconstriction occurs
what happens when sympathetic stimulation decreases
vasoldilation occurs
why is the redistribution of blood important
increases the supply of oxygen to the working muscles
removes waste products from the muscles, such as carbon dioxide and lactic acid
Ensure more blood goes to the skin during exercise
direct more blood to the heart during exercise.
what is arterio- venous oxygen difference
the difference between the oxygen content of the arterial blood arriving at the muscles and the venous blood leaving the muscles.
what is the difference of the arterio-venous oxygen when it is low and then during exercise
at rest the arterio venous differenc is low not as much oxygen is required to the working muscles.
but during exercise as more oxygen is needed for the working muscles the arterio venous difference is high
