Cardiovascular changes Flashcards
How much % does resting cardiac output increase?
30-50%
How much % does resting HR increase by?
25%
How many bts.min does resting HR increase in 1st and 2nd/3rd trimester?
1st = 5-10bts.min
2nd/3rd = 15bts.min
What 2 things stimulates the HR increase?
Increased Oestrogen and human chorionic gonadotropin
What does Oestrogen and progesterone do to resistance??
Reduce peripheral vascular resistance.
How much is peripheral vascular resistance reduced by from the Oestrogen and progesterone?
20%
Why does HR increase due to the peripheral vasodilation?
To maintain/increase BP.
What nervous system is increased so that HR can be increased?
The sympathetic nervous system
How much % does SV increase by?
25%
What causes an increase in blood volume?
Progesterone increases production on Renin which reabsorbs sodium and makes blood more concentrated - expand plasma volume.
What causes an increase in left ventricle size?
Maternal hormones
Oestrogen stimulates myocardial … and increased … ?
Hypertrophy
Contractility
The increased blood volume which stimulates myocardial hypertrophy is what sort of growth?
Eccentric
How much growth in SV even by the 1st trimester?
10%
What happens to afterload which means SV must be increased?
Afterload reduced.
How much is blood volume increased by?
35 -50%
The increased blood volume is offset by an increase in what?
Venous capacitance
- This then means blood pressure is not increased.
What is postural hypertension?
Sudden increased in blood pressure when stand up.
What mechanisms help prevent hyperthermia during exercise?
Increased vasodilation at the skin, increases heat loss
What does Anaemia result from?
Relatively greater increase in plasma volume than red cell mass.
How much % is RBC mass increased by?
20%
How much Hb is there pre pregnancy and then in 3rd trimester?
150g. L pre
120g. L 3rd trimester
Blood becomes slightly … due to increase in blood volume and not as much increase in RBC?
DILATED
TRUE or FALSE - White cell production also increased?
TRUE
Extra fluid in system will help protect against what at birth?
Haemorrhage - blood loss at birth
Why is there a blood clotting risk?
Relaxation of the blood vessel walls with hormonal changes and pressure of uterus on inferior vena cave
How does exercise assist decreasing risk of blood clot?
Increases muscle pump and stop congestion as blood flow increases in legs and feet with exercise
