with correct answers provided
What does the autonomic nervous system contribute to the cardiovascular system in terms of regulation
- ✅✅Sympathetic contributes to circulation
Parasymnpatheitc contributes to heart funciton
What does the sympathetic system contribute to cardiovascular system - ✅✅It increases the activity
of the heart by increasing HR and its strength and volume of pumping
Sympathetic nerves also carry large numbers of vasoconstrictor nerve fibers and only a few vasodilators
Where is the sympathetic vasoconstriction effect most powerful, where is it least potent - ✅✅Most
powerful In kidneys, intestines, and skin
Least potent in skeletal muscle and brain
What vessels arent innervated by sympathetic innervation - ✅✅Capillaries because they are too small
How does sympathetic innervation to precapillary sphincters and metarterioles compare to that of small
arteries, arterioles, and veins - ✅✅There is innervation but is not as dense
How does the role of parasympathetic system in regulation of vascular function compare to sympathetic
- ✅✅It is small in comparison
What nerve is parasympathetic activity expressed through, what does it do - ✅✅The vagus nerve
It causes a marked decrease in heart rate and a slight decrease in heart rate muscle contractility
Where is the vasomotor center of the brain located, generally what does it do - ✅✅Located
bilaterally in the medulla and of the lower third of the pons
, It regulates stimulation of the heart and blood vessel by parasympathetic and sympathetic system
What are the main areas of vasomotor center, what does each region do - ✅✅1. Vasoconstrictor
area: located bilaterally in upper medulla. Neurons here excite preganglionic vasoconstrictor neurons of
the sympathetic nervous system
2. Vasodilator area: located bilaterally in the lower half of the medulla. The neuron in this region inhibit
vasoconstriction area, causing vasodilation
3. Sensory area: located bilaterally in the tractus solitarius in posterolateral portions of medulla and
lower pons
4. Cardioihibitor: acts on parasympathetic to reduce heart activity, located centrally
5. Cardioaccelerator area: acts on sympathetic to increase heart activity
Cycle of action of Sensory area of vasomotor center, give an example of one of the reflexes -
✅✅Neurons receive sensory signals; about blood pressure through vagus and glossipharyngeal
nerves and output signals from this sensory control the activities of both vasoconstrictor and dilator
areas; reflex control of many circulatory functions. Like the barorecptor reflex
What is sympathetic vasoconstrictor tone, how is this proven - ✅✅Under normal conditions the
vasoconstrictor area of the vasomotor center transmits signals continuously to the sympathetic
vasoconstrictor nerve fibers over the entire body, causing slow firing of these fibers
This maintains partial contracted state in blood vessels called vasomotor tone
This can be proven when administering total spinal anesthasia which would reduce blood pressure
What do the lateral portions of the vasomotor center transmit, what does this cause - ✅✅Lateral
portions of the vasomotor center transmit excitatory impulses through the sympathetic nerve fibers to
the heart
This causes increase in heart contractility and HR
What does the medial portion of the vasomotor center transmit, what does this cause - ✅✅Transmits
signals to stimulate adjacent dorsal motor nuclei of vagus nerve
This causes decrease in heart rate