Anatomy Flash cards (16)

Nasal cavity & characteristics

The nasal cavity is divided by the nasal septum into right and left chambers. The entire nasal cavity is lined with mucous membrane that has an abundant supply of blood vessels. As incoming air is channeled through the meat, it is warmed from the heat provided by the nearby bloodstream learn more. The sticky mucus traps small particles such as bacteria and dust and carries them to the pharynx, where they are usually swallowed.

Bronchial tree (bronchi, bronchioles, etc.)

The divisions of the bronchi within the lungs are referred to as the bronchial tree. The distal end of the trachea splits into the right and left primary bronchi within the thoracic cavity. The bronchioles are a series of small tubes that arise as branches from tertiary bronchi within each lung. The bronchioles continue to divide into yet smaller tubes, called alveolar ducts, which terminate as round, microscopic pouches known as alveoli.

Pharynx

The throat, or pharynx, is a chamber that extends from the back of the nasal cavity to the larynx. Its walls are formed by skeletal muscle and are internally linked with mucous membrane.

Larynx

The voice box, or larynx, is a short passageway that connects the pharynx with the trachea. It provides passage to air traveling between these structures, and prevents solid material from entering the trachea. It houses the vocal cords, and thereby provides for the production of sound.

Trachea

The windpipe, or trachea, is a tubular air passageway that is about 12 cm long and 2.5 cm wide. It is located in front of the esophagus and can be felt as a hard, ridged structure just deep to the anterior surface of the neck. It extends from the larynx downward into the thoracic cavity, where it divides into the right and left bronchi.

Alveoli

The alveoli are microscopic air sacs within the lungs. The bronchioles continue to divide into smaller tubes which terminate as round, microscopic pouches, known as alveoli.

Internal vs. external respiration

The internal respiration is the exchange of respiratory gases between the blood and body cells. The external respiration is the exchange of respiratory gases between the lungs and the bloodstream.

Mechanics of breathing

Breathing, or pulmonary ventilation, provides for an exchange of air between the external environment and the spaces within the alveoli of each lung. It sets the stage for the vital process of gas exchange with the bloodstream. Breathing involves two events: inspiration (inhalation, or breathing in) and expiration (exhalation, or breathing out).

Inspiration

Inspiration is the act of drawing air into the lungs. It is also called inhalation.

Expiration

Expiration is the process of expelling air from the lungs to the external environment, or breathing out. It is also called exhalation.

Diaphragm

An internal, circular muscle dividing the thoracic cavity from the abdominopelvic cavity

Surfactant

Surfactant is a lipid secretion produced by the lungs that reduces surface tension within alveoli.

Breathing volumes (tidal, residual capacity, etc.)

Normal quiet breathing moves about 500 ml of air into and out of the lungs with each breath. This is called the tidal volume (TV). The amount of air that can be inhaled forcibly over the tidal volume is the inspiratory reserve volume (IRV) 3100 ml. The maximum amount of air that can be forcibly exhaled after a tidal expiration is about 1200 ml and is called the expiratory reserve volume (ERV). The volume of air remaining in the lungs after a forced expiration averages 1200 ml. This is the residual volume (RV). The total amount of exchangeable air is found by adding the tidal volume, IRV, and ERV. This sum averages about 4800 ml, and is called the vital capacity (VC). The total lung capacity (TLC) is the sum of the vital capacity and the residual volume 6000 ml.

Epiglottis

A part of the larynx that consists of a leaf-shaped piece of hyaline cartilage that forms a movable lid over the opening into the trachea, called the glottis.

Nasal septum, nasal conchie

The two openings at its base are the nostrils, or external names, which are separated by a partition in the midline called the nasal septum. The nasal septum continues behind the external nares to divide the nasal cavity in half. The nasal cavity is divided by the nasal septum into right and left chambers. Attached to the lateral walls of both chambers are three bony projections called nasal conchae.