Biology 12 Unit G - The Respiratory System

Pulmonary ventilation

AKA breathing; physical process of moving air in and out of the lungs

Inhalation/inspiration

Active process of moving air into the lungs; intercostal muscles and diaphragm contract to increase chest volume; larger volume creates less pressure inside the thoracic cavity

Exhalation/expiration

Passive process of moving air out of the lungs; intercostal muscles and diaphragm relax to decrease chest volume; less volume creates more pressure inside the thoracic cavity

Cellular respiration

Process of cells breaking down sugar into energy

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + heat

Formula for cellular respiration

3

Number of lobes in right lung

2

Number of lobes in left lung

Inspiration highway

Path of air moving to the mouth, trachea, bronchi, bronchioles, and alveoli

Bronchioles

Very narrow tubes that enter the lungs; feed into lobes of the lungs

Lobes

Lungs are divided into upper and lower halves that are divided by fissures

Alveoli

Endpoint of bronchioles; have high surface area (100 times the surface area of the skin) like clusters of grapes; site of gas exchange via diffusion; 300 million per lung; membrane is only 1 cell thick; inside walls are coated with a special oily lipoprotein that prevents cohesion that would otherwise cause these to stick and stay closed forever

Pleural membrane

Saran wrap-like membrane surrounding the outside of the lungs

Pleural space/cavity

Between the lung and pleural membrane; filled with serous fluid that decreases friction between the lungs and thoracic cavity as you breath; no damage due to expanding/contracting lungs hitting the chest wall

Ribs

One requirement to help fill the lungs; protects them and provides stability during breathing; move up and out during inhalation; increases chest volume, allowing lungs more space; are hinged

Intercostal muscles

Located between the ribs; during inhalation, these contract using rib bones for stability to pull ribs up and out; during exhalation, these relax and ribs drop down

Diaphragm

Big sheet of muscle (largest in the body); divides the contents of the thoracic cavity from the abdominal cavity

Thoracic cavity

Second-largest hollow space in the body; enclosed by the rib cage, spine, and sternum, and separated from the abdomen by the diaphragm; houses vital organs—primarily the heart and lungs—as well as major blood vessels and airways

Abdominal cavity

Largest hollow space in the human body; houses the majority of your digestive tract, as well as the liver, pancreas, spleen, kidneys, and adrenal glands; enclosed by the diaphragm, abdominal muscles, and spine

External respiration

AKA pulmonary circuit; takes place at the lungs; gas exchange occurs between air in the alveoli in lungs and blood in capillaries

Internal respiration

AKA systemic circuit; takes place at the tissues of the body; gas exchange occurs between blood in capillaries and fluid surrounding cells in our tissue

Red blood cell/erythrocyte

Most abundant cell type in the blood; primary function is to transport oxygen from the lungs to tissues throughout the body and carry carbon dioxide waste back to the lungs to be exhaled; 25 trillion red blood cells in the body

Hemoglobin

Iron-rich protein in red blood cells that carries oxygen from the lungs to the rest of the body and returns carbon dioxide back to the lungs; primary component that gives blood its red colour; made of 4 polypeptide chains and carry heme groups (iron compounds); when red blood cells are exposed to O2, the iron rusts (carries O2); 270 million hemoglobin per red blood cell; 4 heme per hemoglobin

Atmospheric pressure

Column of gas sitting on top of you and pushing you down because gas has mass; measured by a barometer; made up of many gases in the air

760 mm Hg

Normal air pressure at sea level

Partial pressure

Amount of pressure created by one specific part of the entire mixture

Autonomic nervous system

Primary control of breathing; automatically regulates essential bodily functions

Medula/medulla oblongata/brainstem

Where the respiratory centre of the nervous system is located

Chronic obstructive pulmonary disorder

Progressive, long-term lung disease that blocks airflow and makes it hard to breathe; primarily encompasses two main conditions: emphysema (damaged air sacs) and chronic bronchitis (inflamed, mucus-filled airways)

Pneumothorax

AKA collapsed lung; air in pleural space prevents lungs from filling

Emphysema

A form of COPD; alveoli are damaged and have lost surface area; cannot transfer O2 and CO2 as well as a healthy lung can

Pleural effusion

Fluid build-up in the pleural space; decreases lung volume; can lead to collapsed lung

Sleep apnea

Common condition in which breathing stops and restarts many times while you sleep

Pneumonia

Infection that inflames the air sacs in one or both lungs, which can fill with fluid or pus; when lungs fill with fluid (mucus) and water creates a barrier