Control of Respiration in Human Physiology

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What controls the basic rhythm of respiration?

Medullary respiratory center (correct)

Dorsal respiratory group (DRG)

Pontine respiratory group (PRG)

Ventral respiratory group (VRG)

The lungs have a built-in pacemaker similar to the heart.

False

Which areas of the brain contain respiratory centers?

Medulla oblongata and pons

The _____ respiratory group is active during forceful breathing.

ventral Signup and view all the answers

Which group of neurons modifies the basic rhythm of breathing during activities like exercise?

Pontine respiratory group (PRG) Signup and view all the answers

Match the following respiratory components with their functions:

Dorsal respiratory group (DRG) = Normal quiet breathing Ventral respiratory group (VRG) = Forceful breathing Pontine respiratory group (PRG) = Modifying rhythm during activities Central chemoreceptors = Respond to chemical stimuli Signup and view all the answers

Cortical influences allow unconscious control of respiration.

False Signup and view all the answers

What type of receptors are involved in modifying the activity of the respiratory center?

Peripheral nervous system receptors Signup and view all the answers

What are peripheral chemoreceptors primarily responsive to?

Changes in H+ concentration and PCO2 Signup and view all the answers

The Hering–Breuer reflex helps in preventing over-inflation of the lungs.

True Signup and view all the answers

Where are the carotid bodies located?

In the wall of the left and right common carotid arteries. Signup and view all the answers

The reflex that prevents excessive inflation of the lungs is known as the __________ reflex.

Hering–Breuer Signup and view all the answers

What results from the activation of baroreceptors during lung over-inflation?

Inhibition of the DRG Signup and view all the answers

Match the following conditions with their corresponding effects:

Bronchial asthma = Bronchoconstriction and wheezing Emphysema = Difficulty exhaling air Inflation reflex = Prevention of lung over-inflation Stretch receptors = Inhibition of inhalation during over-inflation Signup and view all the answers

What type of muscle contraction is caused by airway irritation during an asthma attack?

Bronchoconstriction Signup and view all the answers

Inhalation is generally more difficult than exhalation for a person with asthma.

False Signup and view all the answers

Study Notes

Control of Respiration

Breathing is automatic, unlike the heart, which lacks a built-in pacemaker.
Lung ventilation relies on coordinating complex skeletal muscle actions.
Unconscious breathing is regulated by respiratory centers in the medulla oblongata and pons.
Thoracic size changes due to breathing muscle contractions and relaxation, controlled by nerve impulses from the brain.
Respiratory center is divided into two areas based on location and function: the medullary respiratory center (controls basic rhythm).
- Two neuron collections: dorsal respiratory group (DRG) (formerly inspiratory area).
  - Normal breathing: DRG neurons trigger diaphragm and external intercostal muscle contractions, causing inhalation.
- Ventral respiratory group (VRG) (formerly expiratory area).
  - Activated with forceful breathing.
  - Pre-Bötzinger complex is crucial in breathing rhythm generation.
Pontine respiratory group (PRG) (pneumotaxic area):
- Active during inhalation and exhalation.
- Modulates the basic breathing rhythm by influencing the DRG.

Chemoreceptors and Respiration

Respiratory center activity can be modified by inputs from other brain areas, peripheral nervous system receptors, and factors related to homeostasis.
Cortical influences allow for conscious control of breathing.
Chemical stimuli influence how quickly and deeply we breathe (e.g., noxious gases, water).
Central chemoreceptors are in or near the medulla oblongata in the CNS.
- Respond to changes in H+ concentration and/or PCO2 in cerebrospinal fluid.
Peripheral chemoreceptors are located in:
- Aortic bodies within the arch of the aorta.
- Carotid bodies in the common carotid arteries' branching points.
- They respond to changes in H+, PCO2, and PO2 in blood.

Stretch Receptors and Inflation Reflex

Stretch receptors in bronchi/bronchioles send signals to the DRG (medullary respiratory center) upon lung over-inflation.
This inhibits the DRG, causing diaphragm and external intercostal muscle relaxation and initiating exhalation.
Stretch receptors stop sending signals when lungs deflate. DRG inhibition stops, and inhalation resumes—the inflation reflex (or Hering-Breuer).
In adults, this reflex protects against lung over-expansion.

Other Influences on Respiration

Other factors influencing respiration include blood pressure, limbic system activity, temperature, pain, anal sphincter stretching, and irritation to respiratory mucosa.

Bronchial Asthma and Emphysema

Bronchial asthma involves an allergic reaction to inhaled substances (e.g., pollen, dust mites).
Excessive mucus and edema in smaller airways impede airflow (bronchoconstriction).
Wheezing sound accompanies air movement through narrowed airways.
Expiration is more difficult than inspiration in asthma.
Emphysema is a degenerative lung condition (destroys alveolar walls and air sacs).
Alveolar surface area declines, reducing gas exchange efficiency.
Loss of elasticity prevents sufficient exhalation.

Chronic Bronchitis

Persistent cough producing mucus for at least three months in two consecutive years.
Symptoms include overweight, cyanosis, peripheral edema, rhonchi, and wheezing.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz explores the automatic and complex nature of breathing regulation in humans. It covers the roles of various brain structures, including the medulla oblongata and pons, in maintaining respiratory rhythm and the mechanics of lung ventilation. Test your understanding of the respiratory centers and their functions.