Chapter 9 Regulation of Arterial Pressure Flashcards
What is the single most important requirement for proper operation of the cardiovascular system?
To provide adequate perfusion of all tissues in the body at all times
What is the system wide consequence of individual changes in local vascular resistance?
Change in total peripheral resistance
How are CO and MAP related (give two equations)
CO = HR x SV MAP = CO x TPR (MAP = (HRxSV) x TPR)
When arterial pressure is abnormal, short term and long term changes occur via what major mechanisms.
Short (seconds to minutes) - adjustments in MAP are made by changes in the activity of the autonomic nerves leading to the heart and peripheral vessels
Long (hours to days) - Blood volume adjustments involving renal mechanisms for fluid regulations are more important
What is the single most important mechanism of short term regulation of MAP?
the arterial baroreceptor reflex
What is the sensory component of the arterial baroreceptor reflex arc
The arterial baroreceptors
Describe in general the afferent pathway of the arterial baroreceptor reflex arc
Bonus points - describe more specifically from the two major baroreceptors
Actions potentials in the baroreceptors stimulate afferent fibers which lead to the CNS.
Carotid sinus = carotid sinus nerve joins glossopharyngeal before entering CNS
Aortic = vagus to CNS (both afferent and efferent nerve)
What occurs in regards to central integration in the baroreceptor reflex arc
Bonus points - Describe central integration in regards to anatomy (afferent, specific medullary centers, parasympathetic nerves/sympathetic nerves leaving)
The CNS contains medullary cardiovascular centers. These centers receive sensory information from the afferent fibers. These centers in the medulla also contain the cell bodies of the efferent fibers of the arc.
The afferent sensory information from the arterial baroreceptors enter the nucleus tractus solitarus. The cell bodies of the efferent vagl parasympathetic cardiac nerves are located in the nucleus ambiguus. Sympathetic autonomic erfferent informaitons leaves via the rostral ventrolateral medulla group of neruons (excitatory spinal path) or via the raphe nucleus (inhibitory)
Most central integration occurs in the medulla. What higher center is also involved
the hypothalamus
nervous control of vessels in which organs is more important?
kidney, skin, splanchnic, brain, heart
the reflex response to a fall in arterial pressure could cause what?
a significant increase in renal vascular resistance and a decrease in renal blood flow without changing the cerebral vascular resistance or flow
Describe the reflex receptors in the heart and lungs
Cardiopulmonary receptors consist of a host of mechanoand chemoreceptors that are in the atria, ventricles, coronary vessels and lungs.
Describe how increased CVP is affected by the cardiopulmonary receptors
increased CVP and volume cause stretch activation of low pressure receptors which increases afferent activity to the medullary centers and elicit a reflex decrease in sympathetic activity.
