HK 3810 Package 1 notes.docx

All inputs to vsm are additive one does not override

Info icon This preview shows pages 9–11. Sign up to view the full content.

View Full Document Right Arrow Icon
All inputs to VSM are additive, one does not override the other (except for physical factors) State of VSM = sum of constrictors + sum of dilators Since we want MAP in the aorta to be at 100 mmHg, arterioles are one of the tools used to maintain it at that Total peripheral resistance (TPR) is the sum of the resistances in body o A large number of resistance arterioles need to be vasoconstricted in order to change TPR bc vasocontricting one set will result in no change in TPR For systemic circulation: CO = (MAP – RAP)/TPR; since RAP = 0, CO = MAP/TPR MAP = CO x TPR Capillaries Downstream of the resistance arterioles Site of exchange of substrates and metabolites o LS can diffuse directly through endothelial cell membranes o NLS (ions, glucose, water) can pass through spaces between the cells (cleft pores) o There are different sizes of cleft pores depending on tissue (skeletal muscle ~ 6-7nm size filter); H2O, glucose, ions, urea can pass through but not plasma proteins (albumin, haemoglobin) Important for cell survival; each cell of the body is approx. 20um from a capillary Important for adjusting blood volume in the short term – what determine fluid movement? o CFC – capillary filtration coefficient Describes fluid permeability characteristics of capillary bed Dependent on: Endothelial cell spacing (cleft pore size) – relatively constant but can be changed based on local environment (histamine – promotes swelling) Surface area of capillaries Number of flowing capillaries at any given time
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
HK 3810 Package 1 Usually constant o Pc – capillary pressure Hydrostatic pressure in the capillary exerted by blood Principle force in capillary filtration Pressure to move H2O from capillaries to ISS Increase MAP increase volume into capillary bed, volume out of capillary bed is constant increase volume and pressure in capillary bed Decrease MAP decrease volume into capillary bed, volume out of capillary bed is constant decrease volume and pressure in capillary bed Increase venous pressure (MCFP) decrease volume out of capillary, volume into capillary bed is constant increase volume and pressure in capillary bed Decrease venous pressure (MCFP) increase volume out of capillary bed, volume into capillary bed is constant decrease volume and pressure in capillary bed Vasoconstrict arterioles (increase resistance) decrease volume into capillary bed, volume out of capillary is constant decrease volume and pressure in capillary bed Decrease resistance in arterioles increase volume into capillary bed, volume out of capillary bed is constant increase volume and pressure in capillary bed o Pt – ISS hydrostatic pressure Pressure exerted bt fluid in ISS Ranges from +5 (tight) to 0 to -6 (loose) mmHg Pressure to move H2O from ISS to capillaries o ∏c – colloid osmotic pressure in capillaries Pressure to move fluid by osmosis
Image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern