Micro & Special Circulations Flashcards
What is the importance of the microcirculation?
What influences the flow of blood through the microcirculation?
Pressure, metabolites, precapillary sphincters, vasocontriction/dilation of smooth muscle via local & systemic factors.
What are the 3 types of capillaries?
What is an Arteriovenous anastomosis?
An Arteriovenous anastomosis is capillary bed bypass
True or false:
Capillary substance exchange between blood & interstitial space occurs via simple diffusion, which is governed by Fick’s first Law of diffusion.
True.
How does the terminal lymphatics function?
- All Lymph on left side of body & both sides below the waste will return to the heart via the thoracic duct which will drain into the subclavian vein
- All lymph from the upper right side of the body will be carried back to the heart via the right lymphatic duct
What causes edema?
Edema occurs when the volume of interstitial fluid exceeds capacity of lymphatics – block or excess filtration
Fluid exchange in the capillaries are dependent on what variables?
Osmotic/Oncotic pressure
Pulls water & metabolites back into the capillaries, back from the interstitial space.
Hydrostatic pressure does what?
Pushes water & metabolites out of the capillary into the interstitial space
Negative net pressure in the capillaries causes what?
Negative net pressure in the capillaries will cause fluid to be pulled into the capillaries from the interstitial space
Positive net pressure in the capillaries causes what?
positive net pressure in the capillaries will cause fluid to be pushed out of the capillaries into the interstitial space.
What are some common pathologies of capillary fluid movement?
What are some common cases & examples of edema formaton?
What are the special circulations of the body?
- Coronary
- Cerebral
- Skeletal
- Cutaneous
- Pulmonary
What are important characteristics of coronary circulation?
** Greatest coronary blood flow is actually during (left ventricular) diastole - anncrease in heart rate shorten diastole, which will decrease coronary perfusion length/time
What are important characteristics of cerebral circulation?
- BBB; lacks fenestrations in it’s capillaries
- extremely complex tight-cell junctions
- high levels of mitochondria
What are the main factors affecting cerebral blood flow?
What is the Cushing’s phenomenon?
Rise in intracranial pressure will cause Cushing’s triad of symptoms:
- High BP
- Bradycardia
- Irregular respiration/breathing
What are important characteristics of skeletal muscle circulation?
Get 20% of cardiac output at rest, but during exercise up to 80% of CO can be allocated
What are some major cutaneous blood flow/microvascular disruptions/disorders?
What are important characteristics of pulmonary circulation?
Special circulations summary
Lecture summary
