Physiology Flashcards
According to Fick’s law, what two things is the diffusion of small, water-soluble substances across a capillary wall dependent on?
Permeability and the concentration gradient
Ultrafiltration typically occurs at the (arteriolar/venular) end of capillary beds?
Arteriolar end
What occurs at the venular end of capillary beds?
Reabsorption
How are exchangeable proteins typically moved across capillary walls?
Vesicular transport
(T/F) Plasma proteins generally cannot cross the capillary wall
True
What is the term for the osmotic pressure due to the presence of colloids dissolved in the blood plasma?
Oncotic pressure
What results from the increased oncotic pressure contained in capillaries due to the inability of colloids to readily diffuse across the capillary wall?
Tendency for movement of water into capillaries
At the arteriolar end of a capillary, the hydrostatic pressure outward is (higher/lower) than the oncotic pressure inward, resulting in ultrafiltration predominating.
Higher
At the venular end of a capillary, the hydrostatic pressure outward is (higher/lower) than the oncotic pressure inward, resulting in reabsorption predominating.
Lower
What type of vessels collect the small volume of fluid and plasma protein that is filtered but not absorbed by capillaries?
Lymphatic vessels
What is the term for the clinical condition in which excess fluid accumulates in the tissues, usually in the interstitial spaces?
Edema
Abnormalities of which Starling force causes the forcing of excess fluid out of the capillaries?
Hydrostatic forces
Right sided heart failure tends to result in high pressure edema, describe the issue.
Pressure in veins is too high → hydrostatic pressure on venular end is too high → decreased reabsorption → edema
What type of Starling force is primarily affected by hypoalbuminemia?
Oncotic pressure
Increased capillary pressure ________ (favors/diminishes) fluid filtration into tissues and __________ (favors/diminishes) reabsorption from tissues.
Favors, diminishes
Pulmonary edema is associated with right/left heart failure.
Left
Edema of what is promoted by right heart failure?
Systemic organs; liver, GI tract
What is released in immune hypersensitivity/allergic reactions that increases vascular permeability leading to edema?
Histamine
The highest level of vascular control is regulation by hormones (Epinephrine, norepinephrine, and angiotensin II) and what type of nerves?
Vasomotor nerves
What are the two principal factors responsible for basal vascular tone?
Tonic sympathetic autonomic nervous system activity and arteriolar smooth muscle cell myogenic activity
An increase in alpha1 receptor activity leads to what? What effect on resistance and blood flow does that then lead to?
Vasoconstriction; increased resistance and decreased blood flow
What two things can cause passive vasodilation?
Decreased alpha1 receptor activity and increased blood pressure
What does increased beta2 receptor activity and increased cholinergic receptor activity cause?
Active vasodilation
Vasodilation is associated with ________ (increased/decreased) resistance and __________ (increased/decreased) blood flow.
Decreased resistance, increased blood flow