Respiratory System Flashcards

Flashcards about the respiratory system.

Larynx

Commonly called the “voice box”, the larynx is involved in breathing, producing sound, and protecting the trachea against food aspiration.

Trachea

A cartilaginous tube that connects the pharynx and larynx to the lungs and allows passage of air. Also known as the “windpipe”, the trachea is a long membranous tube that is capable of lengthening and widening as air passes through. It is the largest airway of the body and it is reinforced with 20 rings of cartilage to keep it from collapsing. The trachea moves into the lungs by branching into two separate tubes called bronchi.

Bronchi

Extensions of the trachea that carry air from the trachea in the lungs. There are two main bronchi that directly originate from the trachea; these main bronchi continue to branch into smaller and smaller bronchi. Each main bronchus supplies air to a single lung. While they are similar in structure to the trachea with cartilage and a mucous membrane, bronchi are also supported with a layer of smooth muscle fibres between the membrane and cartilage.

Bronchiole

As they branch off and become smaller, bronchi eventually undergo a structural change and become bronchioles - smaller, thin-walled airways that lack cartilage and are composed of epithelial tissue cells and smooth muscle fibres. Bronchioles deliver air to little air sacs called alveoli.

Alveoli

Terminal air sacs that are located at the end of the respiratory tree (alveolus/alveolar sac singular). Upon inhalation, the alveoli fill with air; upon exhalation, air leaves the alveoli. They are just one cell thick and lined with a fluid called a surfactant to maintain shape and surface tension, the wall of each alveolus is the site of gas exchange via diffusion. The primary function of an alveolus is to exchange oxygen and carbon dioxide to and from the blood stream. The anatomy of an alveolus consists of an epithelial layer lining the alveolar membrane. Alveoli are further surrounded by blood vessels known as capillaries to allow oxygen and carbon dioxide to move freely between the respiratory and circulatory systems. The endothelial cells of the capillary often fuse with the epithelial cells of the alveoli to allow for rapid diffusion.

Lungs

A pair of spongy respiratory organs that expand and fill with air on an inhale, and deflate and empty of air on an exhale. They are located on either side of the chest and bordered by the diaphragm. Connected to the trachea via the left and right main bronchi, the lungs are the main organ utilized in the respiratory system. The right lung is shorter and wider than the left lung, and the left lung occupies a smaller volume due to the cardiac notch, an indentation on the surface of the left lung which allows space for the heart. The lungs are covered by a pair of serous membranes known as pleurae, which act as a lubricant and allow the lungs to optimize their capacity to expand and contract, in addition to separating the lungs from the wall of the thoracic cavity.

Diaphragm

Located below the lungs, the diaphragm is the major muscle of respiration and separates the abdomen from the chest. During inhalation, the diaphragm contracts and flattens which creates negative pressure, similar to vacuum, and pulls air into the lungs. During exhalation, the diaphragm relaxes and pushes air out of the lungs.

Breathing

The movement of air into and out of the lungs.

External Respiration

The exchange of O2 and CO2 between AIR and BLOOD

Internal Respiration

The exchange of O2 and CO2 between BLOOD and TISSUE FLUID

Cellular Respiration

The process which produces ATP in mitochondria → requires O2 and releases CO2

Vocal Cords

Elastic ligaments called vocal cords (or vocal folds) stretch from the back to the front of the larynx, just at the sides of the glottis.

Tidal Volume

The average human breathes in, on average, 500 mL of air per breath.

Vital capacity

The maximum that can be breathed in per breath, and averages as much as 6000 mL.

Dead air space

The part of the air that is stuck in bronchioles and does not get into the alveoli.

Residual air

About 1000 mL of air remains in the lungs after expiration.

Carbonic Anhydrase

The enzyme in red blood cells that speeds up the reaction as CO2 leaves the blood.

Hemoglobin

An iron- containing respiratory pigment that is found within our red blood cells (RBCs).

Common Cold

Caused by a mild viral infection (about 150 viruses are known to cause colds). Symptoms: sore throat, and watery nasal discharge with mucus.

Influenza

Caused by a more severe viral infection. Symptoms: cold-like symptoms, fevers, and aches.

Bronchitis

Usually caused by viral infection of the nasal cavities that then spread to the bronchi, and causes a secondary bacterial infection.

Pneumonia

Caused by bacteria or viruses which infect the lungs. The lobes of the lungs fill up with mucus and pus.

Emphysema

Most often caused by smoking, which leads to deteriorating bronchioles. This can cut off the alveoli, and lead to the ballooning of the lungs due to trapped air. This trapped air can then cause the alveoli to rupture. Symptoms: coughing, sluggishness, and the starving of oxygen in the heart and lungs

Tuberculosis

Caused by Mycobacterium tuberculosis (MTB) bacteria. Can be detected with a skin test and X-rays. If the bacteria infects the lungs, it can cause the formation of muscle masses called tubercles. These tubercles can cause impairment of breathing, coughing, and release of sputum, which can kill the sufferer.

Lung Cancer

A progressive disease … early detection is important! Progress of disease: 1. lungs are exposed to carcinogenic irritants 2. bronchial cells thicken and callous, and cilia die 3. “atypical cells” start appearing in the thickened bronchial lining 4. some of these cells break loose and penetrate other tissue (known as metastasis) 5. tumours grow, tubes become blocked, lungs collapse, and secondary infections can occur