OIA1004 (TERMS) RESPIRATORY SYSTEM II

Pulmonary Ventilation

Air exchange between atmosphere and lungs.

Inhalation

Active process involving muscle contraction.

Exhalation

Passive process, except during forced exhalation.

External Respiration

Gas exchange between lungs and blood.

Internal Respiration

Gas exchange between blood and cells.

Boyle's Law

Pressure inversely varies with volume at constant temperature.

Diaphragm

Muscle that contracts to facilitate inhalation.

External Intercostal Muscles

Muscles that assist in rib cage elevation.

Lung Compliance

Ease of lung expansion during breathing.

Surface Tension

Force that affects alveolar fluid dynamics.

Thoracic Volume

Volume of the thoracic cavity during breathing.

Intrapulmonary Pressure

Pressure within the lung's airways.

Forced Inhalation

Involves additional muscles like scalenes.

Forced Exhalation

Involves abdominal and internal intercostal muscles.

Gas Exchange

Oxygen and carbon dioxide transfer in respiration.

Respiratory Gases Transport

Mechanisms for oxygen and carbon dioxide in blood.

Regulation of Respiration

Control mechanisms for breathing rate and depth.

Pulmonary Capillaries

Small blood vessels for gas exchange in lungs.

Systemic Capillaries

Blood vessels for gas exchange in tissues.

Factors Affecting Ventilation

Includes air pressure, surface tension, and compliance.

Respiratory System Functions

Involves breathing, gas exchange, and regulation.

Airway Resistance

Friction in respiratory passageways affecting airflow.

Air Pressure Changes

Variations in pressure during pulmonary ventilation.

Surface Tension

Force exerted by alveolar fluid on alveoli.

Alveolar Fluid

Liquid coating alveoli, affecting surface tension.

Pulmonary Surfactant

Lipid-protein complex reducing surface tension in alveoli.

Type II Alveolar Cells

Cells secreting pulmonary surfactant in lungs.

Respiratory Distress Syndrome (RDS)

Condition in premature infants due to surfactant deficiency.

Lung Compliance

Measure of lung stretchability and distensibility.

Elasticity of Lung Tissues

Ability of lung tissues to return to original shape.

Pulmonary Edema

Fluid accumulation in lungs reducing compliance.

Emphysema

Destruction of elastic fibers in lungs, reducing compliance.

Chronic Obstructive Pulmonary Disease (COPD)

Group of diseases causing increased airway resistance.

Airway Diameter

Width of air passages affecting resistance levels.

Sympathetic Nervous System

Part of nervous system reducing airway resistance.

Bronchiolar Dilation

Widening of bronchioles increasing airway diameter.

Inward Pressure

Pressure within alveoli that can cause collapse.

Surface Tension Reduction

Decreased effort needed to expand lungs with surfactant.

Asthma

Condition causing increased airway resistance and difficulty breathing.

Medium-Sized Bronchi

Location where airway resistance peaks during breathing.

Detergent-like Complex

Description of pulmonary surfactant's structure and function.

Tidal Volume (TV)

Air volume per breath at rest, ~500 mL.

Minute Ventilation (MV)

Total air volume inhaled/exhaled per minute.

MV Calculation

MV = respiratory rate x tidal volume.

Inspiratory Reserve Volume (IRV)

Air inhaled forcefully after normal inhalation.

Expiratory Reserve Volume (ERV)

Air exhaled forcefully after normal exhalation.

Residual Volume (RV)

Air remaining after forced exhalation, ~1100-1200 mL.

Inspiratory Capacity (IC)

Max air inspired after normal expiration, IC = TV + IRV.

Functional Residual Capacity (FRC)

Air remaining after normal expiration, FRC = ERV + RV.

Vital Capacity (VC)

Max air expired after max inhalation, VC = TV + IRV + ERV.

Total Lung Capacity (TLC)

Max air in lungs after max inhalation, ~4200-6000 mL.

Dalton's Law

Total pressure equals sum of individual gas pressures.

Partial Pressure

Pressure exerted by each gas in a mixture.

Gas Diffusion

Gas moves from high to low partial pressure.

Henry's Law

Gas dissolved in liquid proportional to its partial pressure.

Gas Solubility

CO2 is 24x more soluble than O2 in blood.

Alveoli

Site of gas exchange with large surface area.

Spirometer

Device measuring air volume exchanged during breathing.

Pulmonary Malfunction Indicator

Decreased minute ventilation suggests lung issues.

Factors Affecting Lung Volumes

Gender, height, age, smoking, and diseases.

Healthy Adult Breathing Rate

Normal rate is 12 breaths per minute.

Minute Ventilation Example

12 breaths/min x 500 mL/breath = 6 L/min.

Lung Volumes vs. Capacities

Volumes are measurable; capacities are inferred.

Respiratory membrane

0.5 µm thick barrier for gas exchange.

Partial pressure

Difference in gas concentration affecting diffusion rate.

Diffusion rate

Increases with higher partial pressure differences.

Gas exchange

Oxygen and carbon dioxide transfer in lungs.

Internal respiration

Gas exchange between blood and tissues.

Solubility of gases

CO2 is more soluble than O2 in plasma.

Ventilation

Amount of gas reaching the alveoli.

Perfusion

Blood flow in pulmonary capillaries.

Ventilation/Perfusion coupling

Matching ventilation with blood flow for efficiency.

Oxygen transport

Process of delivering oxygen to tissues.

Dissolved oxygen

Only ~1.5% of O2 is dissolved in plasma.

Haemoglobin (Hb)

Protein in RBCs that carries oxygen.

Oxyhaemoglobin (HbO2)

Formed when oxygen binds to haemoglobin.

Saturation of haemoglobin

Fully saturated Hb binds 4 O2 molecules.

Factors affecting O2 binding

Includes PO2, blood pH, temperature, BPG.

BPG (2,3-bisphosphoglycerate)

Decreases Hb-O2 affinity, promoting O2 release.

Carbon dioxide transport

CO2 is transported dissolved, bound, or as bicarbonate.

Carbaminohaemoglobin

CO2 bound to haemoglobin's amino groups.

Acidosis

Increased CO2 lowers pH, reducing Hb-O2 affinity.

Alkalosis

Increased pH raises Hb-O2 affinity.

Bicarbonate ions

Main form CO2 is stored in blood.

Respiratory centre

Neurons controlling the rhythm of breathing.

Medullary rhythmicity area

Controls basic rhythm of respiration.

Pneumotaxic area

Regulates transition between inhalation and exhalation.

Apneustic area

Coordinates inhalation and exhalation depth.

Normal respiratory rate

12 to 15 respirations per minute.

Hyperpnea

Increased respiratory rate for extra oxygen needs.

Physical factors

Exercise, coughing, and talking influence breathing.

Conscious control

Voluntary regulation of breathing patterns.

Emotional factors

Emotions can affect breathing rate and depth.

Chemical factors

CO2 and O2 levels regulate respiration.

Negative feedback mechanism

Regulates breathing based on blood gas levels.

Central chemoreceptors

Respond to changes in [H+] or PCO2.

Peripheral chemoreceptors

Detect changes in [H+], PO2, or PCO2.

Upper respiratory tract infections

Includes rhinitis, sinusitis, and pharyngitis.

Lower respiratory tract infections

Includes pneumonia and bronchitis.

Asthma

Chronic inflammatory disorder causing reversible airway obstruction.