Circulatory System Flashcards
structure and functions of arteries/arterioles
thick muscular elastic walls
supply the necessary elements to the bodys organs
structure and functions of capillaries
tiny blood vessels have thin walls. Oxygen and nutrients from the blood can move through the walls and get into organs and tissues. The capillaries also take waste products away from your tissues. Capillaries are where oxygen and nutrients are exchanged for carbon dioxide and waste.
structure and function of pre capillary sphincters
rings of smooth muscle
help to direct blood flow into capillaries
structure and function of veins/venules
thin walls, wide lumen
blood to the heart at a low pressure, deoxygenated blood
pocket valves
little muscle doors
prevent back flow of blood
whats plasma
the fluid part of the body (mainly water) that surrounds blood cells and transports them
whats haemoglobin
an iron containing pigment found in red blood cells, which combines with oxygen to form oxyhemoglobin
whats myoglobin
its an iron containing muscle pigment in slow twitch muscle fibres which has a higher affinity for oxygen than haemoglobin. it stores oxygen in muscle fibres which can be used quickly when exercise begins.
whats mitochondria
often referred to as the powerhouse of the cells as respiration and energy production occur there.
mechanism of venous return
Contraction of the skeletal muscles surrounding veins increases the pressure within the veins, pushing open the proximal valve and forcing blood toward the heart. For example, when calf muscles contract during exercise, blood is forced toward the heart, thus increasing venous return.
what is the Bohr shift
describes the movement of the oxygen dissociation curve to the right of normal. This occurs due to increased levels of carbon dioxide, such as when a person increases their exercise level, which causes an increased concentration of carbonic acid to be formed.
why does the Bohr shift occur
increase in carbon dioxide
decrease in PH(blood more acidic)
blood temp increases
what happens during the Bohr shift
increase in heomoglobin dissociation due to increase in co2 etc
whats the effect of the Bohr shift
has an affect on oxygen delivery to the muscles as there is an increase in resaturation of myoglobin.
The aim of myoglobin is to deposit oxygen and keep full saturation this then helps us with exercise as oxygen can be diffused into the muscles faster.
what is the skeletal muscle pump
when muscles contract and relax meaning they change shape and press on nearby veins to make a pumping effect. This squeezes blood towards the heart
what is the respiratory system
when muscles contract and relax during breathing in or out, pressure change in the thoracic(chest) and abdominal(stomach) cavities. these changes in pressure press on nearby veins and assist blood return to the heart
what mechanisms aid with venous return
- skeletal muscle pump
- respiratory pump
- pocket valves
- gravity
what is venous return
the return of blood to the right side of the heart via the vena cava
what is pulmonary circulation
deoxygenated blood moving from the heart to the lungs and oxygenated blood moving back to the heart
what is systemic circulation
oxygenated blood moving from heart to the body and then the return of deoxygenated blood from the body to the heart
flow chart showing the order of the key blood vessels
heart - arteries - arterioles - capillaries - venues - vein - heart
what is the definition of blood pressure
the force exerted by the blood against the blood vessel wall
what is systolic pressure
the pressure in the arteries when ventricles are contracting
what is diastolic pressure
the pressure in the arteries when the ventricles are relaxing