CARDIO-Circulation

Question 1

What open and close the entrance to the capillary to perfuse them?

Answer 1

Precapillary spincters- via arterioles, these are a small msk ring that contrict and dialate

Question 2

These structures have direct control of local blood flow via capillaries?

Answer 2

arterioles and metaartioles

Question 3

Capillaries role is to do what?

Answer 3

1. Exchange w/in ciruclatory system 2. Local control of blood flow at tissue of organ. 3. Total peripheral resistance

Question 4

Which capillary have diff permeablity based on structure?

Answer 4

All are different depending on location.

Question 5

Describe structure of a capillary?

Answer 5

10billion, single layered wall, Endothelilum + small basement memebran, no smooth msk, some have fenestrated/windows

Question 6

Describe structure of a glomerulus capillary of kidney, brain, and liver?

Answer 6

Kidney-High pressure cap, fenstrated(window). Brain- tight junction via BBB. Liver- gap junctions

Question 7

How are capillaries perfused or shunted?

Answer 7

Perfusion via artieroles, spincter dialate. Shunted spincters contricts, blood either bypasses capilliary bed to venous or continue in arteriole

Question 8

What stucture allows blood to move past the capillary bed to dump/shunt in the venous?

Answer 8

Meteateriole

Question 9

What is intermittent contraction of metarteriole?

Answer 9

Vasomotion- normal intermitency through capillaries

Question 10

What occurs when local tissue is oxygen deprived?

Answer 10

Spincheters dialate to perfuse to capillary bed. If oxygen rich spinchters contrict

Question 11

How is diffusion within capillary flow controlled passively?

Answer 11

Thermal controlled- Warmth quicker. Solubility-Lipid soluble O2, CO2 (faster), concentraction gradient- how much on both sides of membrane

Question 12

Cl, Na, glucose diffuse through what w/in the membrane?

Answer 12

Intracellular pores.

Question 13

What determines molecular permeablity through membranes?

Answer 13

Weight, size, charge, concentration. Ex. Protein, larger, neg. Repelled in cell membranes due membran neg.

Question 14

What is gelatin like, small space, similar to plasma, where structures diffuse through?

Answer 14

Insterstial fluid- Proteins and plasma reside sometimes

Question 15

The arteriole end of the capillary has high hydrostatic pressure, thus > than interstial fluid hydrostatic pressure, then this favors what?

Answer 15

Filtration. Sum of OUTWARD greater than INWARD

Question 16

The venous end of the capillary has low hydrostatic pressure, then this favors what?

Answer 16

Absorbtion- hydrostatic pressure declines. Venous oncotic/collid pressure is low. Sum of INWARD greater than OUTWARD

Question 17

IF the ICF/interstium has high colloid/oncotic pressure, what will occur?

Answer 17

Movement will be OUT from the capillary

Question 18

What are the 4 starling forces?

Answer 18

1. Hydrostaic Pressure/BP of the capillary- push OUT force 2. Instertiial hydrostatic fluid pressure- INWARD force 3. Plasma capillary colloid pressure-substance concentraion INWARD force to dilute blood 4. Instertial fluid colloid/oncotic pressure-substance concentration OUTWARD force

Question 19

What make protein less difusable?

Answer 19

Donning Equilibrium-Sodium, Calcium, Potassim form halo around protein. Serum concentratin don’t always account for that

Question 20

What occures as flow is moved through capillaries?

Answer 20

Hydrostatic pressure decrease due to Net filtration higer on one end of capillery. And low towards venous end

Question 21

Why is venous net absorbtion different from arteriole net filtration accounts for the leak of fluid due to inc filtration across the capillaries?

Answer 21

Returned by the lymphatic system. Capillary don’t absorb everything. Must values stay constant b/c lypmh

Question 22

What is only change amongst capillary bed?

Answer 22

Capillary hydtostatic pressure. To calculate, can simply =Venous Net= Change in BP- Net filtration of capillary

Question 23

Is the circulatory system balanced?

Answer 23

Almost, most of the filtration is absorbed. The 0.3 difference is absorbed by lymphatics

Question 24

Inc pressure= INC filtration= INC fluid accumlated by lymph. This leads to what?

Answer 24

Ascites edema. The lymph can only absorb so much

Question 25

What are characteristic of lymph flow?

Answer 25

1.NO pump 2. One way valve system 3. Not a circuit 4. Lymph nodes accumulate-WBC 5. Most in tight closed location, Axilla, Groin, Neck, near orfics openings. 6. Needs MSK and glands to move 7. Thoracic pressure during inspiration promotes lymph flow 8. Low volume and flow rate system. 2ml/min/2L/day vs HEART 5L/min

Question 26

whay is ICF now a outward force?

Answer 26

Moved over to make +, Closed cavity create negative pressure

Question 27

Fluid volue leaving capillarys is balanced by?

Answer 27

Absorbtion from other capillary and lypmh. Starling equilibrium