PSC 126 Chapter Notes - Chapter 3: Left Ventricular Hypertrophy, Hypertension, Cardiovascular Disease
Notes
● The cardiovascular stress -response
○ Want to increase the force with which your heart beats
○ Sympathetic nervous system causes veins to constrict, get more rigit
■ Causes returning blood to blast through veins w/ more force
■ Blood returns to heart w/ more force, slamming into heart walls
■ Heart walls, like a stretched rubber band, snap back w/ more force
○ Heart rate & blood pressure go up
○ Arteries leading to muscles are relaxed
■ Increases blood flow & energy delivery
○ Blood flow drops to nonessential parts of the body
■ Ex: digestive tract & skin
○ Kidneys
■ Decrease blood flow to kidneys
■ Brain tells kidneys to stop urine formation
● Water needs to be reavsorbed into circulatory system
■ Reabsorptive, bidirectional organs
● Once urine leaves to kidneys and goes to bladder, the bladder is
unidirectional
● When stressed, bladder contains extra weight
○ So body wants to empty bladder (answer to why we wet
our pants when scared)
● Chronic stress and Cardiovascular disease
○ If heart, blood vessels, & kidneys activated every time someone irritates you, you
increase risk of heart disease
○ Cardiovascular disease - number 1 killer in US
Cardiovascular stress- response makes heart & blood vessels work harder for a
while
■ If you trigger them on a regular basis, they will wear out
■ Heart like mechanical pump
■ Blood vessels like hoses
○ 1st step to stress -related disease is developing hypertension, chronically
elevated blood pressure
■ High blood pressure means more force
■ Thus vessels work harder to regulate blood flow
■ Vessels build thicker musclalyer around them to better control the
increased force of bloood blow
● As result, the thicker vessels now have become more rigid, more
resistant to the force of blood flow
○ Which increases blood pressure & vascular resistance
○ Over time, heart muscle wall will thicken
■ Left ventricular hypertrophy
● Increased mass of left ventricle
Document Summary
Want to increase the force with which your heart beats. Sympathetic nervous system causes veins to constrict, get more rigit. Causes returning blood to blast through veins w/ more force. Blood returns to heart w/ more force, slamming into heart walls. Heart walls, like a stretched rubber band, snap back w/ more force. Heart rate & blood pressure go up. Blood flow drops to nonessential parts of the body. Brain tells kidneys to stop urine formation. Water needs to be reavsorbed into circulatory system. Once urine leaves to kidneys and goes to bladder, the bladder is unidirectional. So body wants to empty bladder (answer to why we wet our pants when scared) If heart, blood vessels, & kidneys activated every time someone irritates you, you increase risk of heart disease. Cardiovascular disease - number 1 killer in us. Cardiovascular stress- response makes heart & blood vessels work harder for a while.
