Respiratory System Homeostasis

Respiratory System Homeostasis

• The muscular system supports increased activity of skeletal muscles during exercise, needing a higher breathing rate and depth
• The nervous system has receptors in the nose for smell (olfaction) and vocal folds create sounds via vibrations of air
• The endocrine system produces angiotensin-converting enzyme (ACE) which aids venous blood return to the heart
• The cardiovascular system's respiratory pump supports lymph flow
• The lymphatic system and immunity are aided by hairs in the nose, cilia, mucus, and alveolar macrophages
• The digestive system uses the forceful contraction of respiratory muscles for defecation
• The urinary system and reproductive systems work with the respiratory system to regulate pH and adjust body fluids.

Respiratory System Contributions

• The respiratory system helps regulate pH and adjust body fluids through exhalation of CO₂
• It provides oxygen to support activity during sexual functions and in general activity.

Respiratory System Disorders

• Asthma
• Chronic obstructive pulmonary disease
• Lung cancer
• Pneumonia
• Tuberculosis
• Common cold
• Pulmonary edema
• Cystic fibrosis
• Asbestos-related diseases
• Sudden infant death syndrome
• Acute respiratory distress

Aging and the Respiratory System

• Aging causes a decrease in vital capacity, blood O₂ levels, and alveolar macrophage activity
• Ciliary action of respiratory epithelia is reduced, making the elderly more prone to pneumonia, bronchitis, emphysema, and other issues
• Elderly people are more susceptible to respiratory infections due to reduced respiratory function.

Exercise and the Respiratory System

• The respiratory and cardiovascular systems adjust during exercise
• Cardiac output increases, resulting in increased blood flow to lungs (pulmonary perfusion)
• The diffusion capacity of oxygen may increase threefold during intense exercise, allowing for greater O₂ diffusion

Summary of Stimuli Affecting Breathing Rate and Depth

• Stimuli that increase breathing rate and depth include voluntary hyperventilation, elevated arterial blood PCO₂ (and thus H+), decreased arterial blood PO₂, increased body temperature, and proprioceptor activity.
• Stimuli that decrease breathing rate and depth include voluntary hypoventilation, decreased arterial blood PCO₂ (and thus H+), decreased body temperature, severe pain, and irritation of the pharynx or larynx

Control of Respiration

• Cortical influences allow conscious control over breathing to avoid inhaling noxious gasses or water
• Chemoreceptors, central and peripheral, monitor levels of oxygen and carbon dioxide to provide input to the respiratory center, allowing the body to respond to changes in the body.

Transport of O₂ and CO₂ in the Blood

• 1.5% of oxygen is dissolved in plasma; 98.5% is carried by hemoglobin (Hb).
• 7% of carbon dioxide is dissolved in plasma; 23% is carried by Hb (carbaminohemoglobin); 70% is transported as bicarbonate ions (HCO₃⁻).

External and Internal Respiration

• In external respiration, oxygen diffuses from the alveoli into pulmonary capillaries, while CO₂ moves in the opposite direction.
• In internal respiration, oxygen diffuses from systemic capillaries into tissues, while CO₂ moves in the opposite direction.

Exchange of Oxygen and Carbon Dioxide

• During gas exchange, oxygen moves from the lungs to the bloodstream; Carbon dioxide moves from the bloodstream to the lungs. This exchange occurs between the alveoli and tiny blood vessels (capillaries) in the lungs

Modified Breathing Movements

• Coughing, sneezing, sighing, yawning, sobbing, crying, laughing, and hiccupping are modified breathing movements, or reflexes that can help clear respiratory passages or express emotions
• Hiccupping is a sudden contraction of the diaphragm followed by a spasmodic closure of the rima glottidis

Breathing Patterns and Respiratory Movements

• Eupnea is normal breathing, Apnea is absence of breathing, Dyspnea is difficulty breathing, Tachypnea is rapid breathing, Costal breathing is primarily using the rib cage, and Diaphragmatic breathing primarily uses the diaphragm

Boyle's Law

• Boyle's Law states that the pressure of a gas varies inversely with its volume
• Increased volume leads to decreased pressure; decreased volume leads to increased pressure

Pulmonary Ventilation

• Air flows between the atmosphere and alveoli based on pressure differences caused by alternating contraction and relaxation of respiratory muscles. During inhalation, the diaphragm contracts and the lungs expand, lowering pressure, allowing air to enter. During exhalation, the diaphragm relaxes and the lungs contract, raising pressure, forcing air out.

Blood Supply to the Lungs

• Blood enters the lungs via the pulmonary arteries, and exits via the pulmonary veins
• Blood flow is altered (vasoconstriction or vasodilation) to match the need for oxygen supply in well-ventilated areas.

Respiratory Membrane

• The respiratory membrane is composed of a type I and type II alveolar cells, an epithelial basement membrane, a capillary basement membrane, and the capillary endothelium. This interface is crucial for gas exchange.

Alveoli

• Alveoli are sac-like structures in the lungs where gas exchange occurs. There are two types of alveolar cells, type I and type II.

Lungs

• The lungs are paired organs in the thoracic cavity, enclosed and protected by the pleural membrane.

Bronchi

• At the superior border of the 5th thoracic vertebra, the trachea branches into primary bronchi, one for each lung

Trachea

• The trachea extends from the larynx to the primary bronchi

Larynx

• The larynx, or voice box, contains vocal folds that produce sound when they vibrate
• It's a passageway from the pharynx to the trachea; aids in speech production, and protection of the airway from food and foreign particles.

Pharynx

• The pharynx acts as a passageway for air and food. It's involved in speech sounds and houses the tonsils, which aid the immune system. It comprises nasopharynx, oropharynx, and laryngopharynx.

Surface Anatomy of the Nose

• The nose has four main parts: root, apex, bridge, and external naris (nostrils).

Explore the intricate relationships between the respiratory system and other body systems. This quiz covers how the respiratory system supports various functions such as exercise, pH regulation, and immunity. Test your knowledge on the roles played by different systems in maintaining homeostasis.