Cardio 7 Flashcards
distribution of blood to tissues is based on..
amount and size of arteries
total blood flow through all arterioles =
cardiac output
flow for each arteriole depends on…
resistance
main integrating center for reflex control and distribution of blood
medullary cardiovascular control centre (CVCC)
CVCC
ensures adequate blood flow to brain and heart by maintaining mean arterial pressure
baroreceptor reflex
primary reflex pathway for homeostatic control of mean arterial blood pressure
baroreceptors found on..
aorta and on carotid artery
peripheral chemoreceptors
located on aortic arch and carotid artery; sense alterations in blood/gas conc. and changes in blood pH
peripheral chemoreceptors activation..
changes ventilation within respiratory system
vasovagal syncope
fainting in response to sight of blood, phlebotomy; the combination of decreased CO and decreased peripheral resistance cause a large fall in mean arterial pressure
3 TYPES OF CAPILLARIES
CONTINUOUS, FENESTRATED, SINUSOIDAL (DISCONTINUOUS)
capillary exchange occurs via…
diffusion (trans or paracellular) or transcytosis
bulk flow
mass movement of fluid as the result of hydrostatic or osmotic pressure gradients.
absorption
if bulk flow is resulting in fluid moving into the capillaries
filtration
f bulk flow is resulting in the movement of fluid out of the capillaries
hydrostatic pressure
the pressure in the blood vessels drives fluid out of the capillaries through pores and leaky cell junctions (filtration)
colloid osmotic pressure or oncotic pressure (pi)
the pressure that draws fluid into the capillaries is the pressure created by plasma proteins in the blood
oncotic pressure
osmotic pressure created by proteins
net pressure
hydrostatic pressure - colloid osmotic pressure
positive net pressure
indicates filtration
negative net pressure
indicates absorption
lymphatic vessels
assists cardiovascular system with returning fluid and proteins lost through capillaries
lymphatic vessels are made of..
single endothelial cell layer
lymphatic vessels contain..
- large inter endothelial junctions that act as one way valves
- nodes that contain immune cells
expansion phase of lymphatics
the interstitial hydrostatic pressure is higher than inside the lymphatic causing the microvalves to open and fluid to flow in
compression phase
lymphatic hydrostatic pressure exceeds interstitial, the microvalves close and the secondary valves open.
edema
an abnormal accumulation of fluid in interstitial space
causes of edema
- inadequate lymph drainage
2. disruption in normal balance between capillary filtration and absorption
disruption in normal balance between capillary filtration and absorption caused by..
- increased capillary hydrostatic pressure (heart failure)
- decrease in plasma protein conc. (malnutrition, liver failure)
- increase in interstitial proteins (excessive leakage of proteins out of capillaries)
