Introduction to Respiration Quiz

Learning Objectives

• Define respiration and the three phases
• Identify anatomical components of the upper and lower respiratory systems and their locations
• Explain how respiratory structures' structures match their functions
• List bones/tissues forming the nasal cavity
• Describe histological changes in the bronchial tree (epithelial lining, cartilage support)
• Explain how respiratory structures' histology relates to their physiology
• Explain inhalation and exhalation mechanics
• Define lung volumes and capacities
• Determine gas diffusion direction at respiratory surfaces
• Identify factors affecting hemoglobin saturation
• Compare/contrast oxygen and carbon dioxide transport
• Define the chloride shift and its significance in homeostasis
• Explain breathing control and the low blood pH negative feedback loop
• Describe exercise's effects on the respiratory system
• Explain how smoking affects respiratory function

Introduction to Respiration

• Respiration is the acquisition of oxygen and the elimination of carbon dioxide
• Three steps in the human body:
  1. Pulmonary ventilation
• Gas exchange between atmosphere and lung tissues 2. External respiration
• Gas exchange between lung tissues and blood 3. Internal respiration
• Gas exchange between blood and body tissues

Anatomy of the Respiratory System

• Upper respiratory system
• Nose, nasal cavity, pharynx, and associated structures
• Lower respiratory system

Upper Respiratory System

• The Nose
• Made of bone, cartilage, and connective tissue
• Contains the nasal cavity
• Air enters through external nares (nostrils)
• The Nasal Cavity
• Interior space of the nose
• Bounded by nasal bones and oral cavity
• Divided into left and right halves by the nasal septum
• Lined with mucous membranes containing conchae
• Vibrates to permit singing and speech
• Swirls inhaled air

Lower Respiratory System

• The Bronchi
• Trachea splits into the right and left bronchi
• Carina: ridge at the branch point, sensitive to mucous membrane; triggers cough reflex
• Bronchi branch into smaller tubes called bronchioles, which end in small sacs called terminal bronchioles
• Mucous membranes lining the bronchi change throughout the bronchial tree, with supporting cartilage gradually diminishing and smooth muscle increasing
• The Lungs
• Wrapped in pleural membranes
• Two serous membranes form a space called the pleural cavity, containing lubricating fluid to reduce friction during breathing
• Lungs are separated by the mediastinum
• The superior portion of each lung is the apex
• The inferior portion is the base
• Lobes (divided by oblique and horizontal fissures)
• Superior
• Middle
• Inferior
• Lobules: smaller compartments of each lobe, containing
• Bronchial branches
• Arterioles and venules
• Lymphatic vessels, all wrapped in elastic connective tissue
• Alveoli: microscopic air sacs of the lungs
• Lined with simple squamous epithelium
• Two types of alveolar cells:
• Type I: simple squamous epithelium
• Type II: non-ciliated cuboidal epithelium that produces surfactant, preventing collapse

Respiratory Membrane

• Thin membrane composed of alveoli and associated capillaries
• Layers, from superficial to deep:
• Alveolar wall (Type I and II alveolar cells and macrophages)
• Epithelial basement membrane
• Capillary basement membrane

Blood Supply to the Lungs

• Two sets of arteries
  1. Pulmonary arteries: bring deoxygenated blood from the right ventricle.
  2. Bronchial arteries: bring oxygenated blood from the aorta

Pulmonary Ventilation

• Inhalation: active process involving muscle contraction to expand the thoracic cavity and decrease pressure, causing air to flow in.
• Diaphragm: primary muscle, depresses/contracts to increase the volume
• External intercostals: assist in increasing volume
• Exhalation: passive process involving muscle relaxation and elastic recoil.
• Elastic recoil of the lungs and thoracic cavity decrease is the primary force, causing air to flow out.
• Internal intercostals, external obliques, internal obliques, transverse abdominis, and rectus abdominis (during forceful expiration) may also contract to help further reduce thoracic volume.

Regulation of Breathing

• Respiratory center: cluster of neurons in the brain stem (medulla oblongata and pons) that controls breathing.
• Medullary respiratory group (DRG): controls the basic rhythm of breathing; further divided into dorsal and ventral groups
• Pontine respiratory group (PRG): adjusts the rhythm of breathing, particularly during transitions between inhalation and exhalation
• Factors influencing breathing
• Central and peripheral chemoreceptors: respond to changes in blood CO2, O2, pH; send signals to the respiratory center to adjust breathing rate
• Cortical input: conscious control over breathing (talking, singing)

Factors affecting Respiration

• Partial pressure gradient: affects the rate and direction of gas diffusion. Lower partial pressures result in a slower rate.
• Surface area: larger surface areas facilitate faster diffusion rates.
• Distance: shorter distances between gas exchange sites lead to quicker and more efficient diffusion.

Oxygen Transport

• Hemoglobin (Hb) transports most oxygen in the blood.
• Hb binds to oxygen reversibly, forming oxyhemoglobin (HbO2)
• Factors affecting Hb saturation include partial pressure of oxygen, blood pH, temperature and partial pressure of carbon dioxide (PCO2).

Carbon Dioxide Transport

• CO2 is transported in three forms:
  1. Dissolved in plasma
  2. Bound to hemoglobin (carbaminohemoglobin)
  3. As bicarbonate ions (HCO3−)

Chloride Shift

• Movement of chloride ions (Cl−) across the erythrocyte membrane to maintain ionic balance during CO2 transport.
• Reverse chloride shift aids exhalation by removing HCO3−

Respiratory Processes

• External Respiration: gas exchange between the lungs & blood
• Internal Respiration: gas exchange between the blood & tissues

Test your knowledge on the respiratory system with this quiz. Covering the phases of respiration, anatomical components, and how structures relate to their functions, you'll explore key concepts like lung volumes and the mechanics of breathing. Perfect for students studying human biology or anatomy!