1.1 Venous Return And The Transportatiok Of Oxygen Flashcards
What are the mechanisms that help venous return
Teh skeletal muscle pump The respiratory pump Pocket valves Thin layer of smooth muscle Gravity Suction pump action
What is the skeletal muscle pump
Muscles contract and relax so change shape
The change in shape means that muscles press on the nearby veins and cause a pumping effect
What is the respiratory pump
When muscles contract and relax during breathing in and out, pressure changes occur in the thoracic and abdominal cavities
These pressure changes compress the nearby veins
What are pocket valves
Ensure blood flows in one direction.
What is oxyheamoglobin dissociation
The release of oxygen from oxyheamoglobin to the tissues
What is oxygen stored by in the muscles
Myoglobin
What is the Bohr shift
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 tissue occurs more readily
What causes the Bohr shift
Increase in blood temp
Partial pressure of carbon dioxide increases
pH - more co2 lowers the pH
What is the vascular shunt mechanism
Redirecting of blood flow to areas where it is most needed
What controls blood pressure and blow flow
Vasomotor centre
In medulla oblongata of the brain
What are the 2 mechanisms of blood redistribution
Vasodilation
Vasoconstriction
Of arterioles
What are pre- capillary sphincters
Aid blood redistribution
Tiny rings of muscle located at the openings of capillaries
When they contract blood flow is restricted through capillary
When they relax blood flow is increased
Why is redistribution of blood important
Increase supply of o2
Remove waste products
Ensure more blood goes to skin during exercise to regular body temp
Direct more blood to heart
What is the aterio-venous difference
The difffenec between the oxygen content in the arterial blood arriving at muscles and the venous blood leaving muscles
