Human Respiratory System Overview

Human Respiratory System

• Functions to obtain oxygen and eliminate carbon dioxide through two phases: inspiration and expiration.
• Inspiration refers to the inhalation process of taking in air, while expiration is the exhalation process of blowing out air.

Organs of the Respiratory System

• Nose/Nasal Cavity: Warms, moistens, and filters incoming air; also referred to as external nares.
• Pharynx: Serves as a passageway for the respiratory and digestive systems; commonly known as the throat; leads to the trachea.
• Larynx: Contains vocal cords, known as the voice box.
• Trachea: Keeps the windpipe open; lined with cilia that filter air before it reaches the lungs.
• Bronchi: Two primary branches diverging from the trachea; lead into each lung.
• Bronchioles: Smaller branches from the bronchi leading to lung tissue and ultimately alveoli.
• Alveoli: Small air sacs within the lungs where gas exchange occurs.
• Pleura: Protective membrane surrounding each lung.

Functions of the Respiratory Tract

• Upper Respiratory Tract: Provides air passage, contains smell receptors, filters foreign materials, moistens and warms air, and acts as resonating chambers for voice.
• Lower Respiratory Tract: Maintains open airway, appropriately routes food and air, assists in sound production, transports air to and from the lungs.

Processes of Respiration

• Breathing: Involves air moving into and out of the lungs.
• External Respiration: Refers to gas exchange between air and blood.
• Internal Respiration: Involves gas exchange between blood and tissues.
• Cellular Respiration: Uses oxygen to produce ATP, generating carbon dioxide as a waste product.

Diseases of the Respiratory System

• Asthma: Severe allergic reaction causing tightness of bronchioles.
• Bronchitis: Inflammation of the bronchial lining.
• Emphysema: Deterioration of alveoli leading to loss of lung elasticity.
• Pneumonia: Accumulation of fluid in alveoli, blocking gas exchange.
• Lung Cancer: Characterized by irregular and uncontrollable cell growth in lung tissue.

Human Circulatory System

• Transports nutrients and oxygen to cells and removes waste for excretion.
• Maintains fluid balance and normal temperature in the body.
• Acts as a defense mechanism against harmful pathogens.
• Known as a closed transport system or internal transport system.

Heart Structure and Function

• Heart: Muscular organ, fist-sized, located between lungs and behind the breastbone; surrounded by the pericardium protective membrane.
• Heartbeat: Rhythmic contraction and relaxation of heart muscles for pumping blood.

Blood Composition

• Blood comprises 45% blood cells and 55% plasma.
• Plasma: Nonliving liquid portion, over 90% water, contains proteins, salts, and transported materials.
• Fibrinogen: Protein in plasma essential for blood clotting.
• Red Blood Cells (RBC): Transport gases (O2, CO2); also called erythrocytes, have a lifespan of 100-120 days, produced in the red marrow.
• White Blood Cells (WBC): Defend against pathogens; larger and fewer than RBC, with a lifespan of 13-20 days. Two types: those with granules (neutrophils, eosinophils, basophils) and without (lymphocytes, phagocytes).
• Platelets: Aid in clotting, preventing bleeding; known as thrombocytes, with a lifespan of 3-5 days.

Blood Types and Discovery

• Discovered by Karl Landsteiner; involves antigens A and B on RBCs and corresponding antibodies anti-A and anti-B in serum.
• Blood Types:
  • Type A
  • Type B
  • Type AB: Universal recipient
  • Type O: Universal donor
• Blood-letting: Historical practice of drawing blood from a person.

Types of Blood Vessels

• Arteries: Carry oxygen-rich blood away from the heart to tissues.