Breathing and exchange of gases

What baseline rules dictate an animal's type of respiratory organ?

Habitat and level of organization (e.g., aquatic use gills, terrestrial use lungs).

Which animals breathe using simple body surface diffusion?

Lower invertebrates (like Protozoans, Poriferans, Coelenterates, and Flatworms).

What specialized respiratory structure is used by scorpions and spiders?

Book lungs (distinct terrestrial structures found in specific arachnids).

What mechanism of respiration is utilized by cockroaches and earthworms?

Cockroaches use tracheal tubes; earthworms use their moist skin (cutaneous respiration).

At what exact vertebral marker does the human trachea branch into bronchi?

Fifth thoracic vertebra (T5 level) where the windpipe forks into left and right sides.

What keeps the main human windpipe from flattening or collapsing?

Incomplete cartilaginous rings (16-20 C-shaped hyaline structures that secure the airway).

What anatomical flap acts as a lid to keep food out of the windpipe?

Epiglottis (a yellow elastic cartilage shield that seals the glottis when swallowing).

What specific cell types construct the human alveolar lining?

Type I cells (squamous cells for gas exchange) and Type II cells (septal cells secreting surfactant).

What is the primary function of pulmonary surfactant secreted by Type II cells?

Lowers alveolar surface tension (keeps the tiny air pockets moist and prevents lung collapse).

What structural components form the thin respiratory membrane for diffusion?

Alveolar epithelium, epithelial basement membrane, capillary basement membrane, and capillary endothelium.

How do the right and left human lungs differ in physical lobes?

Right lung has three lobes (superior, middle, inferior); Left lung has two lobes.

Which major respiratory muscles actively contract to pull air into the lungs?

Diaphragm and external intercostal muscles (together they drive normal inhalation).

How do the diaphragm and chest wall change the thoracic space during inhalation?

Diaphragm moves down (anterior-posterior axis expansion); external intercostals pull up/out (dorso-ventral axis expansion).

Which specific muscle groups must contract during active, forceful expiration?

Internal intercostal muscles and abdominal muscles (they pull the ribs back and push the diaphragm up).

What is the average breathing frequency for a healthy adult at rest?

12 to 16 breaths per minute.

What physiological term defines the standard volume of a single resting breath?

Tidal Volume (TV), which averages about 500 mL.

What portion of inspired tidal volume remains in non-exchange pathways?

Respiratory Dead Space Volume (approx. 150 mL trapped in conducting zone pipelines).

What formula defines a person's total Inspiratory Capacity (IC)?

IC = Tidal Volume (TV) + Inspiratory Reserve Volume (IRV) (approx. 3000-3500 mL).

What is Functional Residual Capacity (FRC) and its exact formula?

Air left in lungs after a normal exhale; FRC = Expiratory Reserve Volume (ERV) + Residual Volume (RV).

What is Vital Capacity (VC) and why excludes Residual Volume?

Max air exhaled after forced inhale (VC = ERV + TV + IRV); excludes RV because RV cannot be exhaled.

What instrument records respiratory air volumes and what value can it NOT track?

Spirometer (creates a spirogram); cannot track Residual Volume (RV) or Total Lung Capacity (TLC).

What chemical index is tracked by Ganong’s respirometer and what is its fat value?

Respiratory Quotient (RQ = CO2 evolved / O2 consumed); equals 1.0 for carbs and 0.7 for fats.

Why does carbon dioxide diffuse much faster than oxygen across membranes?

Higher solubility (CO2 is 20-25 times more soluble in blood plasma than O2).

What are the precise partial pressures of O2 and CO2 inside the alveoli?

pO2 = 104 mm Hg; pCO2 = 40 mm Hg (creates the baseline loading gradient).

What are the precise partial pressures of O2 and CO2 in deoxygenated blood?

pO2 = 40 mm Hg; pCO2 = 45 mm Hg (blood returning from cellular tissues).

What are the precise partial pressures of O2 and CO2 in oxygenated blood?

pO2 = 95 mm Hg; pCO2 = 40 mm Hg (blood leaving the lungs).

How is the vast majority of oxygen carried throughout human blood?

As oxyhemoglobin (97% to 98.5% binds to the iron atom in red blood cell hemoglobin).

How many oxygen molecules can securely bind to a single hemoglobin protein?

Four O2 molecules (one for each iron-containing heme subunit).

How much oxygen does 100 mL of healthy blood deliver to resting body tissues?

5 mL of O2 (unloaded from a total oxygen carriage of 20 mL per 100 mL).

What chemical conditions force the Oxygen-Hemoglobin curve to shift to the Right?

Low pO2, high pCO2 (hypercapnia), high acidity (low pH), high temperature, and high 2,3-DPG.

What physiological principle defines the Bohr Effect at the tissue level?

High pCO2 and high H+ ions decrease hemoglobin's affinity for O2, causing oxygen release.

Why does fetal hemoglobin have a stronger oxygen affinity than adult hemoglobin?

Binds 2,3-BPG less strongly (allows fetus to draw oxygen efficiently from maternal placenta).

What are the three core transport methods for carbon dioxide in the blood?

Bicarbonate ions (70%), Carbaminohaemoglobin (23%), and Dissolved in plasma (7%).

What critical zinc-containing enzyme drives bicarbonate production in red blood cells?

Carbonic Anhydrase (CA), which rapidly bonds water and carbon dioxide.

What electrical balancing movement occurs during the Chloride Shift or Hamburger's Phenomenon?

Chloride ions (Cl-) shift into the RBC from plasma to balance exiting bicarbonate ions (HCO3-).

What respiratory feedback mechanism is described by the Haldane Effect?

Oxygen binding in the lungs prompts hemoglobin to displace and release carbon dioxide.

Where is the primary involuntary respiratory rhythm center located in the human brain?

Medulla oblongata (the brainstem core regulating automated breath tracking).

What is the functional role of the pneumotaxic center located in the pons?

Limits inhalation duration (shortens inspiration to step up the overall respiratory rate).

Which specific bodily fluids and chemical shifts activate the brain's chemosensitive area?

Increases in blood pCO2 and hydrogen ions (H+), which lowers overall fluid pH.

Where are the primary peripheral chemoreceptors situated in the circulatory tree?

Aortic arch (aortic bodies) and carotid arteries (carotid bodies).

What clinical pathology characterizes an acute Asthma attack?

Bronchiolar smooth muscle spasms and airway inflammation leading to difficult breathing and wheezing.

What internal damage happens during cigarette-smoke-induced Emphysema?

Alveolar walls break down, elasticity is permanently lost, and gas exchange surface area shrinks.

What dynamic lung condition is categorised under Occupational Respiratory Disorders?

Pneumoconiosis (dust inhalation causing terminal lung scarring and tissue fibrosis).

Define the medical distinctions between Eupnea, Dyspnea, and Hypercapnia.

Eupnea is normal relaxed breathing; Dyspnea is painful/difficult breathing; Hypercapnia is high blood CO2.

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Answer

What is the clinical term for surgical restructuring of the nose?

Rhinoplasty (medical procedure to reshape or reconstruct nasal bone/cartilage).

What condition is characterized by inflammation of the vocal cords?

Laryngitis (causes swelling of the larynx and leads to temporary hoarseness or voice loss).

What muscle regulates the dynamic diameter changes of the trachea?

Trachealis muscle (smooth muscle that spans the rear opening of the cartilaginous rings).

What is the clinical term for inflammation of the pleural membranes?

Pleurisy or Pleuritis (causes friction and sharp chest pain during breathing movements).

What is the buildup of excess fluid inside the pleural space called?

Pleural Effusion (abnormal fluid accumulation that compresses the lung tissue).

What medical procedure involves inserting a needle to drain fluid from the chest?

Thoracentesis (surgical puncture of the chest wall to clear pleural fluid).

Define Pneumothorax and Hemothorax in clinical pathology.

Pneumothorax is air or gas in the pleural cavity; Hemothorax is blood pooling in the pleural cavity.

What is the medical term for a partial or complete collapsed lung?

Atelectasis (deflation of alveoli due to airway obstruction or pressure changes).

Which non-respiratory neuropeptides and lipid mediators are processed by the lungs?

Neuropeptides: Serotonin, Calcitonin, CGRP, GRP; Lipid mediators: Prostaglandins and Leukotrienes.

Define Hypoxic hypoxia and Anaemic hypoxia as listed in your slides.

Hypoxic hypoxia: Low arterial O2 at high altitudes; Anaemic hypoxia: Poor O2 delivery due to low functional hemoglobin.

Define Stagnant hypoxia and Histotoxic hypoxia.

Stagnant hypoxia: Poor delivery due to low cardiac output/vasoconstriction; Histotoxic hypoxia: Cells unable to use O2 due to cyanide poisoning.

What genetic disorder produces unusually thick, sticky mucus that clogs airways?

Cystic Fibrosis (leads to severe congestion and recurring life-threatening lung infections).

What is Bronchiectasis and how does it affect human airways?

Obstructive lung condition where the airways permanently widen, stretch out, and become flaccid.

What viral infection causes swelling of the throat and a loud 'barky' cough?

Croup (common childhood respiratory infection affecting the larynx and trachea).

What condition occurs when an artery in the lung gets blocked by a blood clot?

Pulmonary Embolism (blockage caused by a clot, fat bubble, or tumor fragment floating from elsewhere).

What is Sarcoidosis and how does it manifest in respiratory health?

Inflammatory disease causing tiny clumps of swollen immune cells (granulomas) to develop in the lungs.

Define Hypopnea and Hemoptysis according to clinical respiratory indices.

Hypopnea represents shallow breathing episodes during sleep; Hemoptysis is coughing up blood from the airways.

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Answer

What explicit structural dimensions are assigned to the human trachea?

Tracheal Dimensions: Measures exactly 12 cm in length and 2.5 cm in diameter.

Between which specific cervical vertebrae is the larynx positionally situated?

Larynx Vertebral Level: Located directly above the trachea, spanning from the C4 to C6 cervical vertebrae.

Which specific bones structuralize the margins of the human nasal cavity?

Nasal Cavity Skeleton: Framed by 1 frontal bone, 2 nasal bones, and 2 maxillae bones.

What specific type of ciliated neuro-cells lines the human nasal chambers?

Olfactory Epithelium: Lined by specialized bipolar neurons wrapped in a ciliated matrix.

What are the exact time allocations for individual inhalation vs exhalation phases?

Breathing Phase Durations: Normal inspiration lasts for about 2 seconds, while normal expiration lasts for about 3 seconds.

What exact numerical value denotes the standard human P50 index on the O2 curve?

P50 Value: The partial pressure of oxygen at which hemoglobin reaches 50% saturation is exactly 25 mmHg.

What is the structural order of microscopic structures between bronchioles and alveoli?

Deep Pulmonary Pathway: Progresses from Bronchioles → Alveolar ducts → Atria → Alveolar sacs.

What are the exact partial pressures of O2 across varying mountain altitudes?

Altitude Pressure Drops: Measures 159 mmHg at sea level, dropping down to 110 mmHg at 10,000 ft, and hitting 73 mmHg at 20,000 ft.

How much oxygen gas is carried within every 100 mL of oxygenated blood?

Oxygen Volumetric Carriage: Contains a total equivalent of 20 mL of gaseous O2 (0.3 mL dissolved in plasma, 19.7 mL bound to Hb).

What is the concentration and O2 binding capacity of human hemoglobin?

Hemoglobin Carriage Capacity: Normal blood holds 15 g of Hb per 100 mL, and exactly 1 gram of Hb chemically binds with 1.34 mL of O2.

How much oxygen does 100 mL of blood unload to tissues during strenuous exercise?

Exercise Oxygen Delivery: Delivers approximately 15 mL of O2 per 100 mL of blood under heavy workload conditions.

What total volume of gaseous carbon dioxide is contained in resting venous blood?

Venous CO2 Carriage: Every 100 mL of deoxygenated blood carries an equivalent of 53 mL of gaseous CO2.

What fraction of total lung elastic recoil is directly driven by alveolar surface tension?

Recoil Fractions: Alveolar fluid surface tension accounts for exactly two-thirds (2/3) of overall lung elastic recoil.

What chemical precursors from NaHCO3 and KCl interact during a reverse chloride shift?

Reverse Shift Ions: Cl- ions dissociate from KCl in blood plasma while HCO3- ions dissociate from NaHCO3 inside the RBCs.