THE HUMAN RESPIRATORY SYSTEM Flashcards
INTRODUCTION TO BREATHING
Breathing is something we usually don’t think about, but it’s essential for our survival. On average, a person breathes about 15 times per minute, which adds up to around 21,600 breaths in a single day. Each breath brings oxygen into our lungs, and every exhale releases carbon dioxide from our body.
is the group of organs and tissues in the body that help you breathe. Its main job is to bring oxygen into the body and remove carbon dioxide, which is a waste product. The respiratory system keeps your body supplied with oxygen and gets rid of carbon dioxide so your cells can function properly.
RESPIRATORY SYSTEM
- the nose serves as the primary
entry point for air. Inside the nose, we find the nasal cavity, which warms, moistens, and filters incoming air with the help of mucus and tiny hairs called cilia.
NOSE AND NASAL CAVITY
(RESPIRATORY ORGANS)
- an alternative entry point for air, especially during heavy breathing or nasal congestion. The oral cavity allows larger volumes of air to enter quickly, but unlike the nasal cavity, it does not filter, warm, or humidify the air as efficiently.
MOUTH AND ORAL CAVITY
(RESPIRATORY ORGANS)
- also known as the throat; a muscular passageway that serves both the respiratory and digestive systems by allowing the passage of air to the larynx and food to the esophagus.
PHARYNX (THROAT)
(RESPIRATORY ORGANS)
- commonly called the voice box; located between the pharynx and trachea, it houses the vocal cords and is responsible for sound production. It also helps protect the airway during swallowing.
LARYNX (VOICE BOX)
(RESPIRATORY ORGANS)
- also known as the windpipe; a rigid tube reinforced with cartilage rings that conducts air from the larynx to the bronchi, ensuring an open airway.
TRACHEA (WINDPIPE)
(RESPIRATORY ORGANS)
- the bronchi are the major air passages that branch off from the trachea into each lung. The primary bronchi are the first branches, with one leading to each lung. These then divide into secondary bronchi, which enter the lobes of the lungs, and further into tertiary bronchi, which supply specific lung segments. The bronchi have cartilage in their walls to keep them open and are lined with mucus and cilia to help trap and remove particles.
BRONCHI
(RESPIRATORY ORGANS)
- bronchioles are the smaller, thinner airways that branch off from the tertiary bronchi. Unlike the bronchi, they lack cartilage and are more flexible. They continue to divide into even smaller tubes, ending in respiratory bronchioles, which lead to alveolar ducts and sacs. Bronchioles play a crucial role in directing airflow to different regions of the lungs and are involved in controlling air resistance and distribution.
BRONCHIOLES
(RESPIRATORY ORGANS)
- alveoli are tiny, balloon-like air sacs located at the ends of the respiratory bronchioles. They are the primary site of gas exchange in the lungs.
ALVEOLI
(RESPIRATORY ORGANS)
PULMONARY ARTERIOLE & VENULE
Pulmonary Arteriole - a small branch of the pulmonary artery that delivers deoxygenated blood from the heart to
the alveoli for oxygenation.
Pulmonary Venule - a small vessel that carrie oxygenated blood away from the alveoli and back toward the heart.
(RESPIRATORY ORGANS)
- the smallest blood vessels that wrap around each alveolus; they are the sites of direct gas exchange with the alveolar air.
CAPILLARY
(RESPIRATORY ORGANS)
- a dome-shaped muscle located below the lungs; it contracts and flattens during inhalation to allow the lungs to expand, and relaxes during exhalation.
DIAPHRAGM
(RESPIRATORY ORGANS)
PROCESS OF BREATHING
Breathing begins with inhalation, a process initiated when the diaphragm (a dome-shaped muscle located below the lungs) contracts and moves downward. This action creates negative pressure inside the chest cavity, which causes the lungs to expand. As a result, air is drawn into the body from the outside environment.
SUMMARY OF BREATHING PROCESS:
- You breathe in.
- Air goes through the nasal cavity, gets cleaned and warmed.
- Then it moves through the pharynx and larynx.
- It travels down the trachea.
- Cilia and mucus trap and move out unwanted stuff.
- Air finally reaches the lungs.
- Your diaphragm helps push air in and out as you breathe.
Primary Bronchi
Air enters the lungs through the primary bronchi. The primary bronchus divides, creating smaller and smaller diameter bronchi until the passages are under 1 mm (.03 in) in diameter when they are called bronchioles as they split and spread through the lung.
Alveolar
Ducts are attached to the end of each respiratory bronchiole. At the end of each duct are alveolarsacs, each containing 20 to 30 alveoli.
OXYGEN TRAVEL
This flowchart simplifies a complex process that captures the essential steps involved in oxygen transport and gas exchange within the respiratory system.
- Air enters through the nose or mouth. It passes through the pharynx and larynx. The trachea carries air down into the bronchi.
- The bronchi divide into smaller bronchioles. These bronchioles lead to clusters of alveoli in the lungs.
- In the alveoli, oxygen diffuses into the bloodstream. Carbon dioxide diffuses out of the bloodstream into the alveoli.
- The diaphragm relaxes, pushing air out of the lungs. Air exits through the trachea, larynx, and either the nose or mouth.
GAS EXCHANGE
During external respiration, oxygen-rich air enters the alveoli during inhalation.
Oxygen molecules diffuse across the thin alveolar walls into the bloodstream, where they bind to hemoglobin in red blood cells.
Simultaneously, carbon dioxide (produced by cellular metabolism) diffuses from the blood into the alveoli.
During internal respiration, oxygen is delivered to body tissues, and carbon dioxide is removed from the tissues and transported back to the lungs for exhalation.
refers to the process by which oxygen is carried from the lungs to the tissues via the blood.
Oxygen transport
FORMS OF TRANSPORT
Oxygen exists in two forms in the blood:
- Simple dissolved form (plasma)
- Chemically-bound form (hemoglobin)
• Hemoglobin-bound oxygen accounts for 97% of total oxygen.
• Hemoglobin’s role is central to oxygen transport.
plays a crucial role in oxygen transport by binding to oxygen molecules. Hemoglobin’s primary function is to facilitate the delivery of oxygen to the body’s tissues and organs. This process is essential for cellular respiration, which provides energy for the body’s functions.
Hemoglobin
STEPS OF OXYGEN TRANSPORT
- LOADING - in the lungs, oxygen binds to hemoglobin.
- TRANSPORT - oxygen rich blood is pumped to tissues and circulated throughout the body.
- UNLOADING - hemoglobin releases oxygen where it is needed.
PULMONARY VS PERIPHERAL CAPILLARIES
Pulmonary capillaries (in the lungs): Oxygen is loaded onto hemoglobin.
Peripheral capillaries (in the tissues): Oxygen is unloaded from hemoglobin to cells.
