Lec 10D Flashcards
(40 cards)
What are the two major goals of circulation?
- Proper gas and heat transport
- Arterial blood pressure
These goals are crucial for short-term survival and maintaining homeostasis.
What is the priority of the cardiovascular system at rest?
To maintain consistent delivery of O2 to key organs, especially brain, heart, and kidneys
Proper removal of CO2 and acid is also essential.
What must cardiac output (C.O.) be reset to during activity?
Higher, to boost flow to skeletal muscles and often to the skin for heat removal
This adjustment is necessary to support increased metabolic demands.
What is the primary reason for maintaining arterial blood pressure?
To ensure adequate gas transport
This is considered the first priority of arterial blood pressure regulation.
What is the minimum average pressure needed for ultrafiltration in the kidneys?
About 80 mm Hg
This pressure is necessary for proper kidney function.
What happens if diastolic pressure drops to 50 mm Hg or less?
Blood cannot overcome gravity to reach the top of the human brain
This illustrates the importance of maintaining adequate pressure for brain perfusion.
What are the secondary priorities of arterial blood pressure regulation?
- High enough to overcome gravity and resistance factors
- Not so high that it creates extra work for the heart or risks vascular damage
These factors ensure the heart and vessels remain healthy.
What is the second regulatory priority of arterial pressure?
Homeostasis of arterial pressure
This priority can conflict with other pressure needs.
What is the impact of chronic high blood pressure (Hypertension) on C.O.?
Excessive resistance impedes flow and increases ΔP to restore proper C.O.
This is a common disorder in mammals such as humans and cats.
How does the hypothalamus regulate temperature in mammals?
By dilating cutaneous (skin) arterioles to eliminate excess heat
This can lead to a fall in blood pressure despite reflex responses for vasoconstriction.
True or False: High blood pressure can be lethal within minutes.
False
Low cardiac output (C.O.) and thus low O2 delivery can be lethal within minutes, whereas high blood pressure may take years to be fatal.
Fill in the blank: Proper blood flow for gas and heat transport is the priority of the _______.
cardiovascular system
This priority is essential for short-term survival.
What regulates gas transport and blood pressure?
Arterial sensors and the cardiovascular control center
The cardiovascular control center is located in the medulla.
What is the role of the cardiovascular control center?
Regulates cardiac output and arteriolar resistance
It acts as an integrator receiving input from sensors.
What type of pathway is the efferent pathway from the cardiovascular control center?
Autonomic nervous system
What is the primary feedback mechanism for the cardiovascular control center?
Negative feedback
What are the two priorities monitored by the cardiovascular control center?
- Proper blood flow for gas transport
- Delivery of O2 and removal of CO2
Where are arterial chemosensors located?
Carotid and aortic arteries
What do chemoreceptors respond to?
Low O2 or high acid levels in the blood
What is the main function of chemoreceptors?
To reflexly increase respiratory activity for more O2
What monitors arterial pressure?
Baroreceptors located in the aortic arch and carotid sinus
Why are baroreceptors strategically located?
To provide critical information about arterial blood pressure
