4 - Blood transport Flashcards
What are the 5 blood vessels?
Arteries Veins Capillaries Arterioles Venules
Name the circulation humans have.
Double circulatory system
Name the two circulations in the body and where the blood goes in each.
Pulmonary - from the heart to the lungs and back
Systemic circulation - from the heart to the body
Describe the terms vasoconstriction and vasodilation.
When the arterioles constract and dilate by sphincters contracting and relaxing due to the action of sympathetic nerves, to affect blood flow to muscles.
What are the characteristics of arteries?
Thick, elastic walls
Small lumen
Carry blood away from the heart
What are the characteristics of veins?
Thin walls
Large lumen
Valves to stop backflow of blood
Carry deoxygenated blood back to the heart
What are arterioles and venules?
Smaller veins and arteries that branch from the main veins and arteries. they join the veins and arteries to the capillaries.
What are the characteristics of capillaries?
Tiny blood vessels
Supply nutrients to cells, remove waste materials.
One cell thick
Very close to muscle site and alveoli
Explain the redistribution of blood in exercise.
In exercise blood is not needed in the digestive system so sphincters contract in the arterioles and reduce the blood flow to those areas while exercising. This is why you get cramp if you eat before exercise.
More blood is pumped to the blood surface to cool down.
The blood flow to the brain stays constant.
What is systolic and diastolic pressure?
Systolic - The hearts pressure when contracting.
Diastolic - The hearts pressure when relaxing.
How does the velocity change in each blood vessel?
Velocity is highest in the arteries, medium in the veins and very low in the capillaries.
Describe venous return and the pumps involved.
Venous return are the mechanisms involved in assisting the return of blood to the heart.
Skeletal pump - Muscle action squeezes the veins and forces the blood towards the heart.
Respiratory pump - breathing motion forces the blood to flow towards the heart by increasing the pressure within the chest. When we inhale the abdominals are squeezed which squeeze the veins.
What is the Bohr Shift
Movement to the right of the oxyhemoglobin dissociation curve which results in the release of more oxygen in exercising muscles.
What causes the Bohr Shift and what are the consequences of the shift
Increase in carbon dioxide/ higher blood acidity
Increase in temperature
Presence of lactic acid
Oxygen dissociates from haemoglobin quicker
(Higher affinity for O2 at lungs, lower affinity and muscle site)
What is A-Vo2 Difference
The difference in oxygen levels between the arteries and veins
