Physio 18

Question 1

What is the primary function of local tissue control mechanisms in relation to blood flow?
a) Increasing systemic arterial pressure
b) Redistributing blood flow to different body areas
c) Adjusting blood flow in the tissues and organs of the body
d) Increasing pumping activity by the heart

Answer 1

Adjusting blood flow in the tissues and organs of the body

Question 2

Which part of the autonomic nervous system is described as “by far the most important” for regulating the circulation?

Answer 2

The sympathetic nervous system

Question 3

Through which spinal nerves do sympathetic vasomotor nerve fibers primarily leave the spinal cord?

Answer 3

All thoracic spinal nerves and the first one or two lumbar spinal nerves

Question 4

Which of the following is one of the two routes by which sympathetic nerve fibers pass from the sympathetic chain to the circulation?

a) Directly into the brain stem
b) Through specific sympathetic nerves innervating the internal viscera and heart
c) Via the vagus nerves to the peripheral vasculature
d) Through the phrenic nerve to the diaphragm

Answer 4

Through specific sympathetic nerves innervating the internal viscera and heart

Question 5

Which types of blood vessels are generally innervated by sympathetic nerve fibers in most tissues?

Answer 5

All vessels except the capillaries

Question 6

How does sympathetic innervation of the small arteries and arterioles affect blood flow?

a) It decreases resistance to blood flow, increasing its rate.
b) It increases resistance to blood flow, decreasing its rate.
c) It has no significant effect on blood flow.
d) It only affects the volume of blood, not the flow rate.

Answer 6

It increases resistance to blood flow, decreasing its rate.

Question 7

What is the effect of sympathetic stimulation on large vessels, particularly veins, in terms of blood volume?

Answer 7

It decreases the volume of these vessels, pushing blood into the heart.

Question 8

How does sympathetic stimulation affect the activity of the heart?

Answer 8

It increases heart rate and enhances its strength and volume of pumping.

Question 9

What is the most important circulatory effect of the parasympathetic nervous system?

Answer 9

To control heart rate via the vagus nerves.

Question 10

What are the principal effects of parasympathetic stimulation on heart function?
a) A marked increase in heart rate and enhanced contractility.
b) A slight increase in heart rate and decreased contractility.
c) A marked decrease in heart rate and a slight decrease in heart muscle contractility.
d) No significant effect on heart rate or contractility.

Answer 10

A marked decrease in heart rate and a slight decrease in heart muscle contractility

Question 11

The nervous system controls the circulation almost entirely through which system?

Answer 11

The autonomic nervous system

Question 12

Part of the autonomic nervous system that contributes importantly to regulation of heart function

Answer 12

Parasympathetic nervous system

Question 13

Controls multiple gastrointestinal actions but plays only a minor role in regulation of vascular function in most tissues.

Answer 13

Parasympathetic nervous system

Question 14

Carry large numbers of vasoconstrictor nerve fibers and only a few vasodilator fibers

Answer 14

Sympathetic nerves

Question 15

Organs highly affected by sympathetic vasoconstrictors

Answer 15

1. Kidney
2. Intestines
3. Spleen
4. Skin

Question 16

Located bilaterally mainly in the reticular substance of the medulla and of the lower third of the pons is an area called the _______

Answer 16

vasomotor center

Question 17

Located bilaterally in the anterolateral portions of the upper medulla

Answer 17

vasoconstrictor area

Question 18

The neurons originating in this area distribute their fibers to all levels of the spinal cord, where they excite preganglionic vasoconstrictor neurons of the sympathetic nervous system

Answer 18

vasoconstrictor area

Question 19

Located bilaterally in the ante-rolateral portions of the lower half of the medulla.

Answer 19

vasodilator area

Question 20

fibers from these neurons project upward to the vasoconstrictor area just described; they inhibit the vasoconstrictor activity of this area

Answer 20

vasodilator area

Question 21

Located bilaterally in the tractus solitarius in the posterolateral portions of the medulla
and lower pons.

Answer 21

Sensory area

Question 22

Neurons of this area receive sensory nerve signals from the circulatory system mainly through the vagus and glossopharyngeal nerves

Answer 22

Sensory area

Question 23

Signals from this sensory area then help
to control activities of both the vasoconstrictor and vasodilator areas of the vasomotor center

Answer 23

Sensory area

Question 24

Vasomotor center transmits signals continuously to the sympathetic vasoconstrictor nerve fibers over the entire body, causing continuous slow firing of these fibers at a rate of about one half to two impulses per second

Answer 24

Sympathetic vasoconstrictor tone

Question 25

Impulses from vasoconstrictor area normally maintain a partial state of contraction in the blood vessels, called as?

Answer 25

Vasomotor tone

Question 26

Transmit excitatory impulses through the sympathetic nerve fibers to the heart when there is need to increase heart rate and contractility

Answer 26

Lateral portions of the vasomotor center

Question 27

Large numbers of small neurons located throughout the reticular substance of the _____, ______, _____ can either excite or inhibit the vasomotor center.

Answer 27

pons, mesencephalon, and diencephalon

Question 28

___ ____ of the vasomotor center sends signals to the adjacent dorsal motor nuclei of the vagus nerves, which then transmit parasympathetic impulses through the vagus nerves to the heart to decrease heart rate and heart contractility

Answer 28

Medial portion

Question 29

Heart rate and strength of heart contract ordinarily increase when _____ occurs

Answer 29

Vasoconstriction

Question 30

_____ portions of the hypothalamus cause mainly excitation

Answer 30

Posterolateral

Question 31

_______ portion of the hypothalamus can cause either mild excitation or inhibition

Answer 31

Anterior

Question 32

Parts of cerebral cortex that can either excite or inhibit vasomotor center

Answer 32

1. anterior temporal lobe 2. orbital areas of the frontal cortex 3. anterior part of the cingulate gyrus 4. amygdale 5. septum 6. hippocampus

Question 33

True or False. Widespread basal areas of the brain can have profound effects on cardiovascular function.

Answer 33

True.

Question 34

In which species does dilator fibers release acetylcholine, instead of norepinephrine?

Answer 34

cats

Question 35

What is the primary substance secreted at the endings of the vasoconstrictor nerves?

Answer 35

Norepinephrine

Question 36

On what type of receptors does norepinephrine primarily act on vascular smooth muscle to cause vasoconstriction?

Answer 36

Alpha adrenergic receptors

Question 37

When sympathetic impulses are transmitted to the adrenal medullae, what two hormones do they secrete into the circulating blood?

Answer 37

Epinephrine and norepinephrine

Question 38

In which specific scenario can epinephrine cause vasodilation, and what type of receptor is involved? a) In all tissues, acting on alpha receptors b) In a few tissues, due to a beta adrenergic receptor stimulatory effect c) Only in the brain, acting on muscarinic receptors d) Only in the kidneys, acting on nicotinic receptors

Answer 38

In a few tissues, due to a beta adrenergic receptor stimulatory effect

Question 39

What type of sympathetic nerve fibers, in addition to constrictor fibers, are carried to skeletal muscles?

Answer 39

Sympathetic vasodilator fibers

Question 40

In some animals (like the cat), what substance is released by sympathetic vasodilator fibers at their endings?

Answer 40

Acetylcholine

Question 41

What is the principal area of the brain controlling the sympathetic vasodilator system?

Answer 41

The anterior hypothalamus

Question 42

What is "Emotional fainting" commonly known as?

Answer 42

vasovagal syncope

Question 43

During emotional fainting (vasovagal syncope), what two major physiological changes occur that lead to a rapid fall in arterial pressure and loss of consciousness? a) Increased heart rate and systemic vasoconstriction b) Muscle vasodilator system activation and strong vagal cardioinhibitory signals to the heart c) Increased respiratory rate and sweating d) Release of large amounts of norepinephrine and epinephrine

Answer 43

Muscle vasodilator system activation and strong vagal cardioinhibitory signals to the heart

Question 44

Three major simultaneous changes that occur when the nervous system rapidly increases arterial pressure

Answer 44

1. Most arterioles of the systemic circulation are constricted. 2. The veins (and other large vessels) are strongly constricted. 3. The heart itself is directly stimulated by the autonomic nervous system.

Question 45

How rapidly can nervous control increase arterial pressure? a) Within minutes to hours b) Within seconds, often doubling pressure within 5 to 10 seconds c) Over the course of several days d) Only during extreme physical exertion

Answer 45

Within seconds, often doubling pressure within 5 to 10 seconds

Question 46

How rapidly can sudden inhibition of nervous cardiovascular stimulation decrease arterial pressure? a) Within 1 to 2 hours b) To as little as one-half normal within 10 to 40 seconds c) Only very slowly over several minutes d) It cannot decrease pressure rapidly.

Answer 46

To as little as one-half normal within 10 to 40 seconds

Question 47

What happens in the brain at the same time the motor areas are activated for exercise, leading to increased arterial pressure? a) Inhibition of the reticular activating system b) Decreased stimulation of the vasomotor center c) Activation of most of the reticular activating system of the brain stem d) Activation of the parasympathetic system only

Answer 47

Activation of most of the reticular activating system of the brain stem

Question 48

What is the "alarm reaction" described as during extreme fright?

Answer 48

A rise in arterial pressure by as much as 75 to 100 mm Hg within a few seconds

Question 49

What type of reflex mechanisms primarily operate subconsciously to maintain normal arterial pressure?

Answer 49

Negative feedback reflex mechanisms

Question 50

What are the stretch receptors that initiate the baroreceptor reflex called?

Answer 50

Baroreceptors or pressoreceptors

Question 51

Other term for baroreceptors

Answer 51

Pressoreceptors

Question 52

Where are baroreceptors extremely abundant? a) In the capillaries of the skin b) In the wall of each internal carotid artery (carotid sinus) and the aortic arch c) In the walls of pulmonary veins d) In the brain ventricles

Answer 52

In the wall of each internal carotid artery (carotid sinus) and the aortic arch

Question 53

Signals from the "carotid baroreceptors" are transmitted through small Hering's nerves to which larger nerves?

Answer 53

Glossopharyngeal nerves

Question 54

Signals from the "carotid baroreceptors" are transmitted through small Hering's nerves to Glossopharyngeal nerves, and then to what brainstem area?

Answer 54

tractus solitarius in the medulla

Question 55

At what arterial pressure range are carotid sinus baroreceptors not stimulated at all?

Answer 55

Between 0 and 50 to 60 mm Hg

Question 56

How do baroreceptors respond to a rapidly changing pressure compared to a stationary pressure? a) They respond less to rapidly changing pressure. b) They respond much more to a rapidly changing pressure. c) Their response is identical regardless of pressure change rate. d) They only respond to stationary pressure.

Answer 56

They respond much more to a rapidly changing pressure.

Question 57

After baroreceptor signals enter the tractus solitarius, what are the net effects on the circulatory system? a) Vasoconstriction and increased heart rate b) Vasodilation of veins and arterioles, and decreased heart rate and strength of contraction c) Increased peripheral resistance and increased cardiac output d) No effect on blood vessels, only on heart rate

Answer 57

Vasodilation of veins and arterioles, and decreased heart rate and strength of contraction

Question 58

Why is the baroreceptor system called a "pressure buffer system"?

Answer 58

Because it opposes either increases or decreases in arterial pressure

Question 59

Known as the baroreceptor system

Answer 59

Pressure buffer system

Question 60

What is the approximate range within which mean arterial pressure remained throughout the day when baroreceptors were functioning normally in the observed dog?

Answer 60

85 and 115 mm Hg

Question 61

Types of chemosensitive cells are chemoreceptors sensitive to: (3)

Answer 61

Oxygen lack Carbon dioxide excess Hydrogen ion excess

Question 62

Where are the two main carotid bodies located?

Answer 62

In the bifurcation of each common carotid artery

Question 63

At what arterial pressure level does the chemoreceptor reflex become a powerful arterial pressure controller?

Answer 63

Below 80 mm Hg

Question 64

What are the stretch receptors in the walls of the atria and pulmonary arteries called?

Answer 64

Low-pressure receptors

Question 65

What is the "Volume Reflex" primarily responsible for? a) Directly increasing heart rate b) Causing significant reflex dilation of afferent arterioles in the kidneys and decreasing ADH secretion to increase fluid loss c) Increasing systemic vasoconstriction in response to volume overload d) Triggering immediate muscle contraction

Answer 65

Causing significant reflex dilation of afferent arterioles in the kidneys and decreasing ADH secretion to increase fluid loss

Question 66

What is the nervous reflex that causes an increase in heart rate due to an increase in atrial pressure, helping to prevent damming of blood?

Answer 66

The Bainbridge reflex

Question 67

What is the overall response called when a baroreceptor or chemoreceptor reflex elicits nerve signals through skeletal nerves to abdominal muscles, helping to translocate blood toward the heart?

Answer 67

The abdominal compression reflex