Lecture 4 Flashcards
which term refers to the mechanism that describes the ability of a tissue to adjust its own blood supply through vasomotion or angiogenesis?
autoregulation
what is autoregulation?
ability of a tissue to adjust its own blood supply through vasomotion or angiogenesis?
what do vasoactive chemicals do?
what are 3 examples of vasoactive chemicals?
stimulate vasodilation
histamine, bradykinin, prostaglandin
what is angiogenesis?
growth of new blood vessels
what is hypercapnia?
excess of CO2 in blood
a general insufficient blood flow to a tissue is called ___
ischemia
what is the medullary ischemic reflex and what does it do?
monitors blood perfusion to brain
when perfusion to brain drops:
- vasoconstriction of arteries except those supplying the brain
- increased contractility force
- increased HR
what do vasoactive chemicals do?
stimulate vasomotion
what is vasomotion?
vasoconstriction or vasodilation
what does the hormone do?
angiotensin II
potent vasoconstrictor that raises BP
what does the hormone do?
aldosterone
promotes Na+ retention, which increases blood volume and raises BP
what does the hormone do?
natriuretic peptides
promotes Na+ excretion, which reduces blood volume and lowers BP
what does the hormone do?
antidiuretic hormone
increases BP by promoting water retention
acts as a vasoconstrictor at extremely high concentrations
excess of CO2 in blood is known as…
hypercapnia
By which process does the medulla oblongata monitor its own blood supply and activate corrective reflexes when it senses a state of ischemia?
medullary ischemic reflex
what does the hormone do?
epinephrine and norepinephrine
adrenal and sympathetic catecholamines that bind to alpha-adrenergic receptors on the smooth muscle of most blood vessels
stimulates vasoconstriction and raises blood pressure
what are chemicals given off by systemic capillary blood to the perivascular tissues?
glucose
antibodies
hormones
oxygen
what are the effects of antidiuretic hormone (ADH)?
vasoconstriction
water retention
what is oncotic pressure?
difference b/n colloid osmotic pressure of blood and tissue fluid
what can cause systemic edema?
failure of right ventricle
how does net filtration pressure change from arterial end of a capillary bed to the venous end?
NFP is greater at the arterial end of a capillary bed which forces liquids to move out of the capillary at the arterial end of the bed and then be reabsorbed at the venous end
what refers to return of blood to the heart?
venous return
A process in which endothelial cells pick up material on one side of the plasma membrane by pinocytosis or receptor-mediated endocytosis, transport the vesicles across the cell, and discharge the material on the other side by exocytosis is called ___
transcytosis
what are the mechanisms of venous return?
1) pressure gradient
2) gravity
3) skeletal muscle pump
4) thoracic (respiratory) pump
5) cardiac suction
interstitial fluids typically enter the venous end of a capillary bed via which process?
osmosis
Tissue fluids that are not reabsorbed by blood capillaries are absorbed by which of the following?
lymphatic capillaries
True or false: Large veins of the neck are normally partially collapsed and their venous pressure is close to zero.
T – when sitting or standing, gravity does all the work pushing blood back to the heart –> large veins of the neck are normally collapsed and venous pressure is close to zero
Which condition presents a threat of suffocation as fluid replaces air in the lungs?
pulmonary edema
The thoracic pump does which of the following?
aids in venous flow from abdominal to thoracic cavity
Which is the most important force in venous flow?
pressure generated by the heart
Which statement best summarizes the general process of capillary fluid exchange?
Fluid moves out of a capillary bed at the arterial end, exchanges materials with the tissue cells, then reenters the blood at the venous end.
The mechanism by which contracting limb muscles squeeze blood out of the compressed part of a vein in only one direction is known as which of the following?
The skeletal muscle pump
Which conditions can be caused by failure of the right ventricle?
Systemic edema
The thoracic pump generates force by which of the following?
Increased abdominal pressure created during inhalation
Interstitial fluids typically enter the venous end of a capillary bed via which process?
Osmosis
True or false: In the skeletal muscle pump, muscle contractions squeeze the blood in veins and valves making sure that the blood flows only in one direction.
T – The skeletal muscle pump is dependent upon contractions of skeletal muscle and venous valves to prevent backflow of blood.
