Cardiac Output and Autonomic Nervous System

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Questions and Answers

Which divisions of the nervous system are responsible for the following events: You're experiencing some anxiety while reviewing your anatomy notes, and your glossopharyngeal nerve monitors blood pressure in your aortic sinus, resulting in the contraction of smooth muscle in the walls of your blood vessels?

Parasympathetic system

Afferent system (correct)

Somatic efferent system

Sympathetic system (correct)

Which divisions of the nervous system are responsible for the following events: as you prepare lunch in your kitchen, your vestibulocochlear nerve detects a buzzing sound, resulting in you voluntarily turning your head towards the sound?

Sympathetic system

Afferent system (correct)

Parasympathetic system

Somatic efferent system (correct)

Blood reflexes, hormones, and neural centers can modify cardiac output (CO) when necessary. Modifying CO is important under different circumstances, and our body does so by manipulating our heart rate (HR) and stroke volume (SV). Which of the following conditions would ultimately DECREASE your CO?

A patient is administered a positive chronotrope.

Sympathetic nerves stimulating the pacemaker cells

More blood entering the ventricles to cause the ventricular reflex.

The cardiac reflex centers send signals along parasympathetic nerves. (correct)

Norepinephrine release from the adrenal glands.

The conducting system of the heart includes some modified structures that allow the propagation of an electrical signal throughout the heart. Which of the following statements below is FALSE about this system?

The cells of the SA node are self-excitatory as they gradually repolarize on their own, causing contraction. Signup and view all the answers

What is the primary role of the autonomic nervous system?

To regulate involuntary bodily functions Signup and view all the answers

Which component of the peripheral nervous system carries sensory signals?

Afferent nervous system Signup and view all the answers

During which state is the parasympathetic nervous system most active?

While at rest Signup and view all the answers

Which effectors are primarily controlled by the somatic nervous system?

Skeletal muscles Signup and view all the answers

How do the subdivisions of the autonomic nervous system generally interact?

Their antagonizing activities balance bodily functions Signup and view all the answers

Which cranial nerve is NOT involved in the parasympathetic nervous system's rest-and-digest processes?

Cranial nerve V Signup and view all the answers

Which of the following statements accurately describes the peripheral nervous system?

It connects the central nervous system to the limbs and organs. Signup and view all the answers

What function does the autonomic nervous system NOT regulate?

Voluntary movement of limbs Signup and view all the answers

What primarily activates the sympathetic nervous system?

Stressful or dangerous situations Signup and view all the answers

Which part of the spinal cord contributes to the nerves that control heart rate and contraction strength?

Thoracic and lumbar regions Signup and view all the answers

How is cardiac output calculated?

Heart rate multiplied by stroke volume Signup and view all the answers

What role does the sinoatrial (SA) node play in the heart?

Depolarizes to initiate heartbeats Signup and view all the answers

What is the effect of norepinephrine on the SA and AV nodes?

It increases their rate of self-depolarization Signup and view all the answers

What is a primary factor that leads to changes in stroke volume?

The preload or volume of blood returning to the heart Signup and view all the answers

During what scenario would the body utilize both HR and SV adjustments effectively?

Stabilizing blood pressure during large fluctuations Signup and view all the answers

Which structure allows for the electrical signal to travel from the atrioventricular node to the ventricles?

Atrioventricular bundle Signup and view all the answers

What effect does hypoperfusion have on pyruvate metabolism?

Pyruvate is metabolized anaerobically, producing lactic acid. Signup and view all the answers

Which system is primarily responsible for acute responses to increase cardiac output during shock?

The sympathetic nervous system Signup and view all the answers

What is a primary consequence of ATP insufficiency during severe shock?

Impaired operation of the Na+/K+ ion pump Signup and view all the answers

Which response is NOT a part of the body's compensation mechanisms during shock?

Enhanced diuresis to eliminate excess fluids Signup and view all the answers

Which of the following statements about the RAA system is correct?

It leads to peripheral vasoconstriction. Signup and view all the answers

What can result from the rupture of lysosomes during metabolic acidosis?

Release of reactive oxygen species and cell death Signup and view all the answers

During distributive shock, which change is typically observed?

Loss of sympathetic nervous activity Signup and view all the answers

Which of the following best describes the cellular impact of sodium concentration increase in shock?

Cellular edema and dysfunction of organelles Signup and view all the answers

What primarily influences stroke volume?

End diastolic volume Signup and view all the answers

How does ventricular hypertrophy affect stroke volume?

It limits stroke volume by reducing ventricular space. Signup and view all the answers

What effect does increased arterial pressure have on end systolic volume?

It increases end systolic volume. Signup and view all the answers

Which of the following best describes shock?

Failure of the circulatory system to supply adequate blood. Signup and view all the answers

What happens during decompensation in shock?

Heart rate can no longer maintain blood pressure. Signup and view all the answers

How is blood pressure related to vascular resistance?

Blood pressure is positively correlated with vascular resistance. Signup and view all the answers

What signifies the development of morbidities in shock?

Duration of hypoxia on the cells. Signup and view all the answers

Which factor contributes to maintaining low end systolic volume?

Effective contractility of the ventricles. Signup and view all the answers

Study Notes

Cardiac Output, Autonomic Nervous System, and Shock

Cardiac output is the volume of blood pumped by the heart per minute, calculated by multiplying heart rate (beats per minute) by stroke volume (volume per beat).
The autonomic nervous system regulates involuntary functions like heart rate, blood vessel tone, digestion, and urination.
The autonomic nervous system has two divisions: the sympathetic nervous system and the parasympathetic nervous system, working antagonistically.
The sympathetic system prepares the body for stress ("fight or flight"), increasing heart rate and blood pressure.
The parasympathetic system promotes rest and digestion, decreasing heart rate and blood pressure.

Autonomic Nervous System

The central nervous system (CNS) integrates and coordinates nervous signals, including the brain and spinal cord.
The peripheral nervous system (PNS) includes cranial nerves and spinal nerves that carry sensory and motor signals to and from the brain and spinal cord.
The PNS is further divided into afferent (sensory) and efferent (motor) divisions.
The efferent system has somatic (voluntary) and autonomic (involuntary) components.

Peripheral Nervous System

Afferent (Sensory) division: Carries sensory signals from receptors to the CNS.
Efferent (Motor) division: Carries motor signals from the CNS to effectors (muscles, glands).
Somatic nervous system: Controls voluntary movements of skeletal muscles.
Autonomic nervous system: Controls involuntary functions (e.g., heart rate, digestion).
- Further divided into sympathetic and parasympathetic systems.

Shock

Shock is a circulatory failure where tissues and organs don't receive enough blood.
Hypoxia (low oxygen) is a primary cause of shock complications.
Initial compensatory mechanisms (e.g., sympathetic nervous system response) maintain blood pressure and perfusion temporarily but are often overwhelmed in severe cases.
Decompensation occurs if compensatory mechanisms fail, leading to tissue damage and organ failure.
The two major responses are sympathetic activation(acute; increasing heart rate, blood pressure), and renin-angiotensin-aldosterone (RAA) system (chronic response to maintain blood pressure by increasing blood volume).

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Description

This quiz covers key concepts related to cardiac output, the role of the autonomic nervous system, and the physiological responses of the body to stress and relaxation. Understand how heart rate and stroke volume are critical to maintaining blood flow and how the sympathetic and parasympathetic systems interact. Test your knowledge on these fundamental aspects of human physiology.