[Exam 2] Lecture 1 Flashcards
What typically happens to blood when there is a significant blood loss?
blood can pool in the legs if not regulated
blood pressure may drop
The body has mechanisms to prevent blood pooling and maintain arterial pressure.
What are the two main baroreceptors involved in maintaining blood pressure?
- Carotid baroreceptors
- Aortic arch baroreceptors
Carotid baroreceptors are connected to the brainstem via the glossopharyngeal nerve, while aortic arch baroreceptors are connected via the vagus nerve.
What is the primary neurotransmitter involved in regulating systemic vascular resistance (SVR)?
Norepinephrine
Norepinephrine is released locally by nerves or dumped into circulation by adrenal glands.
True or False: The kidneys are protected circulatory beds during systemic stress.
False
The coronary circulation and central nervous system are the most protected, while the kidneys are less so.
What happens to the kidneys during increased stretch in the atria?
Urine output increases
This is due to reduced sympathetic tone to the kidneys, helping to decrease blood volume.
Fill in the blank: The Renin-Angiotensin-Aldosterone System (RAAS) helps regulate _______.
Blood pressure
RAAS is crucial for maintaining blood pressure during systemic changes.
What is the role of vasopressin in the cardiovascular reflex system?
It can increase systemic vascular resistance (SVR) during emergencies
Vasopressin release is typically modulated by changes in osmolarity.
What is Atrial Natriuretic Peptide (ANP) primarily responsible for?
Increasing urine output and reducing blood volume
ANP is released when the right atrium is overstretched.
What does Brain Natriuretic Peptide (BNP) indicate in heart failure treatment?
BNP Increase: Ventricles are stretched, treatment is not working
BNP Decrease: Ventricles are less stressed, treatment is working
What is a consequence of increased blood volume on circulation rate?
Slower circulation rate
This can lead to coagulation problems and increased risk of blood clots.
What happens when compensatory mechanisms like Angiotensin II are removed?
The overall ability to maintain cardiac output and blood pressure decreases
This highlights the importance of these mechanisms in cardiovascular stability.
What is the primary function of the autonomic nervous system in low-pressure areas?
To regulate kidney output based on blood volume and pressure
Stretch receptors in veins and atria signal the kidneys to adjust urine output.
True or False: ANP and BNP are effective natriuretic agents for long periods.
False
They are effective for only a couple of weeks, necessitating the use of diuretics for long-term management.
What is the effect of beta-blockers on the cardiovascular system?
They reduce the effectiveness of epinephrine and norepinephrine at the heart
This can impair compensatory mechanisms during stress.
What is the purpose of ANF/ANP in the cardiovascular system?
To prevent problems caused by excess blood volume expansion
ANF (Atrial Natriuretic Factor) and ANP (Atrial Natriuretic Peptide) are hormones that help regulate blood pressure and fluid balance.
What is the average blood volume in the human body?
Approximately 5 liters
What is the plasma portion of blood volume?
About 3 liters
What is hematocrit?
The proportion of blood volume that is made up of red blood cells, typically around 0.4
What is oncotic pressure and what is its normal value?
The pressure exerted by proteins in the blood plasma, typically 28 mmHg
What happens if 20% of blood volume is lost?
Not typically fatal, but can lead to significant physiological changes
How much plasma is lost when 1 liter of blood is lost?
About 600 cc’s
What happens to fluid distribution after blood loss?
Fluid from the interstitial compartment shifts into the cardiovascular system
What is the effect of losing plasma proteins on oncotic pressure?
It decreases oncotic pressure, making it harder to maintain blood volume
Why can normal saline be problematic for volume replacement?
Only 1/4 to 1/5 remains in the cardiovascular system; the rest goes to the interstitium
systemic circulation can handle this, the pulmonary circulation can not = pulmonary edema
