Cardiovascular system Flashcards
What are erythrocytes?
red blood cells
what are leukocytes?
white blood cells
what are thrombocytes?
platelets
what is the function of thrombocytes and where are they formed?
formed in bone marrow from large cells called megakaryocytes
stop bleeding by forming a ‘plug’
what is the function of erythrocytes and where are they formed?
transports oxygen from lungs to tissues
formed in bone marrow
what volume of the blood does plasma take up?
55%
What is vasodilation?
widening/relaxation of the blood vessels (particularly arteries)
what is vasoconstriction?
narrowing/contraction of the blood vessels
what are some common causes of vasoconstriction?
medications
pain
infection
smoking
dehydration
what are some common causes of vasodilation?
alcohol
medications
emotional stress
sepsis
change in body temp
what are baroreceptors and where are they located?
specialised nerve endings that monitor blood pressure, located in the carotid sinus (neck) and the aortic arch
what are chemoreceptors and where are they located?
detect changes in oxygen/CO2 content of the blood, located in the carotid sinus (neck) and aortic arch
What would be a typical physiological response to hypertension?
bradycardia (slow HR) and/or vasodilation
What would be a typical physiological response to hypotension?
tachycardia (fast HR) and/or vasoconstriction
What would be a typical physiological response to low oxygen levels/high CO2 levels
increase in heart rate, respiratory rate and blood pressure
What 2 centres of the brain are responsible for blood pressure control?
Hypothalamus
Medulla oblongata
How does the brain respond to changes in blood pressure?
Hypothalamus and medulla oblongata adjusts heart rate, stroke volume and the size of vessel lumen to regulate BP
What role do hormones play in blood pressure changes?
epinephrine and norepinepherine (released from adrenal glands) can rapidly increase heart rate and cause vasoconstriction which raises BP
