Exam 7 CV Vascular Physiology
Exam 7 CV Vascular Physiology
Terms in this set (10)
What mechanisms control flow to an organ?
Flow = Change in pressure/Resistance 1. Pressure difference 2. Resistance a) Decrease radius to ↑ resistance and ↓ flow to organ
What are the physiologic situations that control cardiac output?
Heart trate and contractility influenced by 1. Sympathetics = ↑ 2. Parasympathetics = ↓ 3. Epinephrine = ↑ Remember
Venous Return (VR) = Cardiac Output (CO)
(CO) *VR=ΔP/R: Venous return is a type of flow. (Remember F=ΔP/R) ??
What is MAP (mean arterial pressure) and How do you find it? What is systolic pressure and diastolic pressure and how do you find them?
a. MAP = Pdiastole+1/3(Pp) (Pp = pulse pressure) b. Pulse pressure = Psys - P dia c. MAP also = 2/3Pd + 1/3Ps (Mike's easier formula, the math checks out) d. MAP = CO x TPR (cardiac output x total peripheral resistance) i.CO = HR x SV (heart rate x stroke volume)
Discuss the main points of working a story problem about filtration vs absorption.
a. Hydroscopic pressures (pushes away from itself - FILTRATION FORCE) i. Capillary pressure (Pc) 15-35mmHg - main one that tends to be the only one to change. ii. Interstitial fluid pressure (IFP or Pt) averaged ~0mmHg b. Colloidal osmotic (oncotic) pressures (pulls towards) i. Plasma oncontic pressure (πp) 28mmHg - high due to lots of proteins in blood ii. Tissue oncontic pressure (πt) 3mmHg - Albumin is large and tends to stay in blood c. Filtration (Cap hydro P + Tissue oncotic P) - Absorption (Cap onc P + Tissue Hydro P) = either net filtration or absorption d. "The only thing that really tends to change is capillary hydroscopic pressure)
What is the peripheral circulation circuits?
Basic Circuit: Conduit arteries -> resistance arteries ->arterioles->apillaries->venules ->eins Two main circuits 1.Pulmonary: to the lungs a) Arteries are deoxygenated, veins are oxygenated b) Connects right ventricle to left atrium c) All blood flow goes to one organ (Lung receives 100% of cardiac output) 2. Systemic: to the body a) Arteries are oxygenated, veins are deoxygenated b) Connects left ventricle to right atrium. c) Each organ only receives a fraction of cardiac output. d) Much higher arterial pressure
What are the functions and histology of the lymphatic vessels.
FUNCTION: i. Returns protein from tissues to the vascular system ii. Maintains low interstitial fluid pressure and helps prevent edema iii. Lymph propulsion requires lymphatic contraction and/or external compression of the lymphatics iv. 80-90% of fatty acids absorbed by small intestine are transported by lymphatics HISTOLOGY i. Overlapping endothelial cells form flap-like valves ii. Anchoring filaments attached to lymph vessel to keep vessel open even in times of ↑ pressure/swelling iii. Propulsion from collecting lymphatics (pressure increases are you get to larger vessels, which pushes lymph up gradient, and valves prevent backflow) iv. Present in all organs except CNS and bone
What are the locations of the BP sensors and mechanism by which they function?
Baroreceptors (sense pressure and send stimuli to medulla) 1. Aortic Arch 2. Carotid Sinus Mechanism: 1. Increase pressure -> Increase BR activity Ends with Decrease in pressure (MAP = CO x TPR) ***** 1. pressure -> Baroreceptor activity 2. Baroreceptor activity -> PSNA, SNA 3. PSNA, SNA -> heart rate, contractility -> CO 4. SNA -> dilation of arterioles and venules 5. Arteriolar dilation -> TPR 6. Venodilation -> Vv, EDV -> SV -> CO 7. CO X TRP -> pressure (MAP = CO X TPR)
What are the definitions and implications of encased tissue (swelling)?
a.Encased tissue swelling: like pulp of a tooth, or brain in a skull
i. ↑ volume will quickly and drastically ↑ pressure (limiting total ability to ↑ volume further which would normally compensate for the ↑ pressure in a non-enclosed tissue)
ii. Compression of venule, which further ↑ pressure, and ↑ filtration
iii. Compromised blood flow -> ischemia/necrosis
What is the relationship between venous return and cardiac output?
VR=CO: Venous return = cardiac output (the heart cannot pump out blood it doesn't receive)
What is the organ distributions for parallel circulations?
Parallel circulation distributions: ??