Respiratory SystemChapter 23

Superficial To Deep

Nose Produces mucus; filters, warms and moistens

incoming air

Superficial To Deep

Pharynx Passageway for air and food

Superficial To Deep

Larynx Air passageway; prevents food from entering

lower respiratory tract Houses vocal cords

Superficial To Deep

Trachea Air passageway; cleans, warms and moistens

incoming air

Superficial To Deep

Pleurae Produce lubricating fluid and

compartmentalizes lungs

Superficial To Deep

Lungs House passageways of bronchial tree and

alveoli

Superficial To Deep

Bronchial Tree Air passageway connecting trachea with

alveoli; warms and moistens incoming air

Superficial To Deep

Alveoli Main sites of gas exchange

Who is the Main Player?

ALVEOLI Site of gas exchange Oxygen and Carbon Dioxide

Inspiration and Expiration

Atmospheric pressure at sea level is equal to 760 mmHg.

In order to inhale, pressure inside the lungs must decrease by at least 1.

Inspiration and Expiration

Inspiratory muscles contract (diaphragm descends; rib cage rises)

Inspiration and Expiration

Thoracic cavity volume increases

Inspiration and Expiration

Lungs stretched; intrapulmonary pressure drops

Inspiration and Expiration

Intrapulmonary pressure drops (at least 1 mmHg relative to the atmosphere)

Inspiration and Expiration

Air (gases) flows into lungs down its pressure gradient until intrapulmonary pressure is 0 (equal to atmospheric pressure)

Inspiration and Expiration

In order to exhale, pressure must be greater in the lungs than outside.

Inspiration and Expiration

Inspiratory muscles relax (diaphragm rises; rib cage descends due to gravity)

Inspiration and Expiration

Thoracic cavity volume decreases

Inspiration and Expiration

Elastic lungs recoil passively; intrapulmonary volume decreases.

Inspiration and Expiration

Intrapulmonary pressure rises (at least 1 mmHg relative to the atmosphere)

Inspiration and Expiration

Air (gases) flows out of lungs down its pressure gradient until intrapulmonary pressure is 0

Inspiration and Expiration

Intrapleural pressure is always -4mmHg compared to intrapulmonary

pressure Pleural fluid secures the pleurae together,

similar to two slides held together by water.

Inspiration and Expiration

The importance of the negative pressure is: Any condition that equalizes the intrapleural

pressure with intrapulmonary pressure (or atmospheric) causes lung collapse.

Inspiration and Expiration

The presence of air in the intrapleural space is called pneumothorax

One lung can be fine and the other be collapsed since they are in separate cavities

Structure and Function

External respiration, or ventilation, brings oxygen into the lungs

Internal respiration exchanges oxygen and carbon dioxide between blood and body cells

Cellular respiration changes acid produced during metabolism into harmless chemicals in the cells

Mechanics of Breathing

Following the Inhalation Process

Air enters the respiratory system through the nose or mouth

Air from the nose or mouth is then funneled through the throat and into the trachea

The trachea branches into two tubes called bronchi

Following the Inhalation Process

Each bronchus enters one of the lungs and then branches into smaller tubes called bronchioles

The bronchioles have small sacs at their ends called alveoli

Capillaries in the walls of the alveoli exchange oxygen and carbon dioxide by the process of diffusion

Assessment Techniques

Rate The normal rate of respiration varies with age,

gender, posture, exercise, temperature, and other factors

Character Respirations should have a regular rhythm,

occurring at regular intervals

Sounds Breath sounds can be heard by using a stethoscope

Assessment Techniques (continued)

Lung volume The amount of air that can be brought into the

lungs is called respiratory capacity

Blood gases Studies measure how much oxygen (O2) and carbon

dioxide (CO2) are in the blood, the blood's pH and other gases

Respiratory Capacity

Disorders of the Respiratory System

Anthrax Caused by spores of the bacterium

Asthma attack May result from exposure to an allergen, cold

temperature, exercise, or emotion

Atelectasis A collapse of part or all of a lung, caused by a

tumor in the thoracic cavity, pneumonia, or injury

Disorders of the Respiratory System (continued)

Bronchitis An infection of the bronchi

Carbon monoxide poisoning Occurs from breathing carbon monoxide

Chronic obstructive pulmonary disease A group of chronic respiratory disorders including

asthma, chronic bronchitis, and pulmonary emphysema

Disorders of the Respiratory System (continued)

Cold A respiratory infection

Cystic fibrosis A genetic disorder of the exocrine glands

Emphysema The alveoli lose elasticity and become dilated and

do not exchange gases well

Disorders of the Respiratory System (continued)

Hay fever A respiratory inflammation caused by allergens

such as plants, dust, and food

Lung cancer Directly linked to smoking and smoke products

Disorders of the Respiratory System (continued)

Pleural effusion A condition in which air or fluid enters the pleural

cavity

Pleurisy An inflammation of the membranes that line the

lungs

Pneumonia An inflammation of the lungs, in which a buildup of

excessive moisture impairs breathing

Disorders of the Respiratory System (continued)

Respiratory distress syndrome A condition that occurs when the alveoli do not

inflate properly

Sinusitis An inflammation of one or more of the paranasal

sinuses

Sudden infant death syndrome (SIDS) A respiratory disorder of newborns

Disorders of the Respiratory System (continued)

Tuberculosis Caused by bacteria that are difficult to destroy, and

it can be transmitted through the air

Upper respiratory infection Caused by a virus or bacteria in the nose, pharynx,

or larynx