The Human Respiratory System Biology 314 Mr. Doron
Game Plan • Introduction to the respiratory system • Pathway the air takes • Role of the nasal cavity • Role of the pharynx • Role of the epiglottis • Role of the trachea • Role of the bronchi & lungs • Fun FAQ’s (yawning, sneezing, hiccups)
Respiratory System Nasal Cavity Mouth Trachea Bronchioles Lung Diaphragm
Human Respiratory System • The respiratory system has two parts • The respiratory airways (nasal, cavity, pharynx, trachea, bronchi) • The lungs • What pathway does air take in the respiratory system? • Nasal cavity --> pharynx --> trachea --> bronchi --> lungs
What is the role of the nasal cavity? • Hairs: filters out the largest foreign particles in the air that enters the nostrils • Capillaries: warm up the air that is inhaled • Mucous glands: moisten the air
The Role of the Pharynx • Pharynx: crossover point (for the digestive and respiratory tracts). • collects incoming air from the nose and passes it downward to the trachea (windpipe).
The Role of the Epiglottis • Known as the switching mechanism • It is a flap of tissue that guards the entrance to the trachea, closing when anything is swallowed that should go into the esophagus and stomach
What is the role of the trachea? • The larynx is situated at the upper end of the trachea. • Contains vocal chords • In males it’s the adam’s apple.
Role of the Trachea Con’t • The walls of the trachea are lined with numerous cilia (hair) and mucous glands • The mucus secreted by the mucous glands capture the foreign particles that have escaped nasal filtration. • The beating of the cilia move the particles now coated with mucus back to the pharynx. • At the pharynx, they are either swallowed down the esophagus or expelled from the respiratory tract.
Role of the Pharynx • Serve as the crossover point • Serves as the pathway that either • Air enters the respiratory tract or • Food enters the esophagus
Role of the Bronchi • Extensions of the trachea • Branch into the bronchioles • Carry air to the lungs • Have cilia and mucous glands
Role of the Lungs • Each bronchus enters a lung and branches into smaller bronchi known as bronchioles. These in turn subdivide into millions of alveoli. • Alveolus is the functional unit of the lungs • It is here that venous blood (carbon – dioxide carrying blood) is oxygenated to become arterial blood (oxygen carrying blood) • Thus, oxygen enters the alveolus • Carbon dioxide leaves the alveolus
A Picture is Worth 1000 words Chest Anatomy
More Pictures X ray of human chest
Air The ribs Intercostal muscles Enters the body Move out and up Contract, moving the rigs up and out, the diaphragm contacts and moves down Work in Class / Homework • Do Page 83, 84 & 85. Copy in your notes #1-
Why Do You Yawn? • When you are sleepy or drowsy the lungs do not take enough oxygen from the air. This causes a shortage of oxygen in our bodies. The brain senses this shortage of oxygen and sends a message that causes you to take a deep long breath---a YAWN.
Why Do You Sneeze? • Sneezing is like a cough in the upper breathing passages. It is the body's way of removing an irritant from the sensitive mucous membranes of the nose. Many things can irritate the mucous membranes. Dust, pollen, pepper or even a cold blast of air are just some of the many things that may cause you to sneeze.
What Causes Hiccups? • Hiccups are the sudden movements of the diaphragm. It is involuntary --- you have no control over hiccups, as you well know. • There are many causes of hiccups. The diaphragm may get irritated, you may have eaten to fast, or maybe some substance in the blood could even have brought on the hiccups.