CV Regulation And Cardiac Output Flashcards
Short term BP regulator?
Baroreceptors
Long term BP regulator?
RAAS
Cranial nerve involved in Carotid Sinus?
IX (Glossopharyngeal)
Cranial nerve involved in Aortic Arch?
X (Vagus nerve)
What would an increase in BP in the aortic arch and/or carotid sinus do?
- ⬆️ parasympathetic activity.
2. ⬇️ sympathetic activity
What would a decrease in BP in the aortic arch and/or carotid Sinus do?
- ⬇️ parasympathetic activity
2. ⬆️ sympathetic activity
What does activation in baroreceptors do to ADH?
- ⬇️ADH secretion
Drugs/hormones that ⬆️ MAP? (Vasoconstrictors)
- NE (norepinephrine) via Alfa1 receptors (Gq) –> Ca++
- EPI (epinephrine) via Alpha 1 (Gq)
- Angiotensin II via AT1 receptor (Gq)
- ADH via V1 receptor (Gq)
Drugs/Hormones that ⬇️ MAP? (Vasodilators)
- ⬇️ sympathetic (NE–> Alpha 1 stimulation)
- EPI stimulation via Beta-2 receptors (Gs-cAMP)
- NO
- Adenosine, CO2, K+ and H+
Name the upstream and downstream portions for Venous Return (VR):
- Mean Systemic Filling Pressure (Psf) = 7 mmHg
UPSTREAM - Right Atrial Pressure (RAP)= 0 mmHg
DOWNSTREAM
Mean Systemic Filling Pressure (Psf) depends on what factors?
- Volume = ⬆️ Volume –> ⬆️Psf and ⬇️Volume –> ⬇️Psf
2. Compliance = ⬆️Compliance –> ⬇️Psf and ⬇️Compliance –> ⬆️Psf
What are the 4 determinants of Cardiac Output (CO)?
- HR
- Contractility
- Afterload
- Preload
How does Exercise-induced Tachycardia prevent SV from falling?
- ⬆️Sympathetic –> ⬆️VR
- ⬆️ Contractility
- ⬆️ Conduction Velocity
- ⬆️ Skeletal Pump –> ⬆️ VR
Why does CO fall with tachyarrythmias ?
- ⬆️HR –> ⬇️diastolic ventricular filling –> ⬇️CO.
- Sympathetic is unable to fully compensate.
- No muscle pump –> ⬇️ VR
Why does TPR ⬇️ in exercise but MAP ⬆️ slightly?
Because MAP = CO x TPR and CO ⬆️⬆️ more than TPR ⬇️, thereby MAP is slightly elevated.
What vascular changes does exercise induce?
- Local vasodilation in active muscle due to local chemical changes (NO, K+, H+, CO2, adenosine, etc).
- Vasoconstriction in GI and Renal system.
- ⬆️SBP and ↔️DBP = Slight increase in MAP.
What Pressure difference is there between arteries and veins do to gravity?
- There’s no difference. Both increase by 80 mmHg
Why when placing a central venous line does the patient have to be in Trendelenburg position?
- To prevent embolism.
Explanation: Trendelenburg position —->⬆️ Central Venous Pressure –> Prevents Air Embolus from forming
What happens to the BP when you take it above the heart level?
- It’s lower than it should be
What happens when you take BP lower than the heart level?
- BP is higher than normal .
What happens to VR and CO when a person goes from supine to upright WITHOUT compensation?
- ⬇️ VR –> ⬇️CO
Explanation:
- ⬆️Volume and pressure in dependent veins (below heart)
- ⬇️VR
- ⬇️CO
What happens in order to compensate for ⬇️CO when going from supine–> upright ?
- Activation of Baroreceptors—> ⬆️Sympathetic and ⬇️PNS –> ⬆️TPR ⬆️VR and ⬆️HR (SV and CO)
What is the relationship between Pulse Pressure (PP) and SV and Arterial Compliance?
PP = directly proportional to SV
PP = inversely proportional to Arterial Compliance
PP = SV/AC
Factors affecting Systolic Pressure ?
- STROKE VOLUME (main factor)
- Contractility
- Arterial Systemic Compliance (Aorta) –> arteriosclerosis
Factors affecting Diastolic Pressure?
- Blood volume
- TPR
- HR
- SV
Factors that increase PP?
- ⬆️ SV (⬆️⬆️SBP and ⬆️DBP)
2. ⬇️ Compliance (⬆️ SBP and ⬇️DBP)