RESPIRATORY SYSTEM

Jhia Anjela D. Rivera1,2

1Department of Biology, College of Science, Polytechnic University of the Philippines2Department of Biological Sciences, School of Science and Technology, Centro Escolar University

RESPIRATORY SYSTEM

VENTILATION EXTERNAL RESPIRATION

O2 and CO2 BLOOD TRANSPORTATION

INTERNAL RESPIRATION

RESPIRATION

• allows the exchange of these gases between the air and the blood• Four processes included:

• Ventilation (movement of air into and out of thelungs)

• External Respiration - gas exchange between theair in the lungs and the blood

• Transport of O2 and CO in the blood• Internal Respiration - gas exchange between theblood and the tissues

FUNCTIONS OF THE RESPIRATORY SYSTEM• GAS EXCHANGE - allows oxygen from the air to enter the

blood and carbon dioxide to leave the blood and enter theair

• REGULATION OF BLOOD pH - can alter blood pH by changingblood carbon dioxide levels

• VOICE PRODUCTION - Air movement past the vocal foldsmakes sound and speech possible

• OLFACTION - sensation of smell occurs when airbornemolecules are drawn into the nasal cavity

• PROTECTION - preventing their entry into the body and byremoving them from respiratory surfaces

RESPIRATORY SYSTEM

• Divided into the upper and lower respiratory tract

FUNCTIONAL DIVISION

CONDUCTING ZONE

Function: for air movement exclusively

Organs: Nose, Pharynx, larynx, trachea, tracheobronchial tree

RESPIRATORY ZONEFunction: gas exchange between the air and blood

Organs: Alveoli, Respiratory membrane, lungs

NOSE•Also called nasusConsists of:•External nose – a visible structure thatforms the prominent feature of the face•Nasal cavity – extends from nares tochoanae•Nares / Nostrils – external openings of thenasal cavity

•Choanae – openings into the pharynx, nasalpassages that connect nose to the throat

NOSE•Nasal Septum – partition dividing thenasal cavity into right and left parts•Conchae – composed of three bonyridges•Meatus – located beneath eachconchae

NOSE

NOSE

PHARYNX•Opening for both digestive andrespiratory system•Receives air from the nasal cavity andreceives air, food, and drink from theoral cavity3 Regions•Nasopharynx•Oropharynx• Laryngopharynx

PHARYNX

NASOPHARYNX• located posterior to the choanae andsuperior to the soft palate• Soft Palate

• Incomplete muscle and connective tissue partitionseparating the nasopharynx from the oropharynx

• prevents swallowed materials from entering thenasopharynx and nasal cavity

• Uvula• posterior extension of the soft palate

ADENOID/PHARYNGEAL TONSIL• Located at the posterior surface of thenasopharynx which helps defend the bodyagainst infection

• Two auditory tubes from the middle ears open intothe nasopharynx. Air passes through them toequalize air pressure between the atmosphereand the middle ears.

OROPHARYNX•extends from the soft palate to the epiglottis

• Fauces – opening of the oral cavity into theoropharynx

• Palatine tonsils and Lingual tonsils – two sets of tonsilslocated near the fauces

OROPHARYNX

EXTERNAL NOSE

LARYNGOPHARYNX•extends from the tip of the epiglottis to theesophagus and passes posterior to the larynx• Food and drink pass through thelaryngopharynx to the esophagus

LARYNGOPHARYNX

LARYNX• located in the anterior part of the throatand extends from the base of the tongue tothe trachea•passageway for air between the pharynxand the trachea•connected by membranes and/or musclessuperiorly to the hyoid bone and consists ofan outer casing of nine cartilagesconnected to one another by muscles andligaments

LARYNX• thyroid and cricoid cartilages maintain anopen passageway for air movement•prevents the entry of swallowed materialsinto the LRT and regulates the passage of airinto and out of the LRT•vocal folds are the primary source of soundproduction

LARYNX•Has 9 cartilages

• 6 are paired• 3 are unpaired• Thyroid – largest unpaired cartilage, also knownas Adam’s apple

•Cricoid – most inferior unpaired cartilage, formsthe base of the larynx on which the othercartilages rest

LARYNX

LARYNX

EPIGLOTTIS•attached to the thyroid cartilage andprojects superiorly as a free flap toward thetongue• Two pairs of ligaments extend from theanterior surface of the arytenoid cartilagesto the posterior surface of the thyroidcartilage• Vestibular folds (false vocal chords) – superiorligament

• Vocal folds (true vocal chords) – inferiorligament

EPIGLOTTIS

EPIGLOTTIS

TRACHEA•Windpipe•Membranous tube attached to the larynx•Consists of dense regular connective tissue andsmooth muscle reinforced with 15–20 C-shapedpieces of hyaline cartilage, that protects thetrachea and maintain an open passageway forair

• has an inside diameter of 12 mm and a length of10–12 cm, descending from the larynx to the levelof the fifth thoracic vertebra

TRACHEA

TRACHEA•Divides to form 2 smaller tubes – mainbronchi (extends to the lungs)•Carina – most inferior tracheal cartilage thatforms a ridge that separates the openingsinto the main bronchi

TRACHEOBRONCHIAL TREE• Term for all the respiratory passagewaysbeginning from the tracheaMain Bronchi

Lobar Bronchi (2°)

Segmental Bronchi (3°)

Bronchioles

Terminal Bronchioles ( → respiratory bronchioles)

TRACHEOBRONCHIAL TREE

ALVEOLI• small, air-filled chambers where gasexchange between the air and blood takesplaceTerminal Bronchioles

Respiratory bronchioles

Alveoli

Alveolar Ducts

Alveolar Sacs

ALVEOLI• Small, air-filled chambers where gasexchange between the air and blood takesplace•Alveolar Ducts - long, branching hallways withmany open doorways

•Alveolar Sacs – chambers connected to 2 ormore alveoli

ALVEOLI

RESPIRATORY MEMBRANE•where gas exchange between the air andblood takes place• formed mainly by the alveolar walls andsurrounding pulmonary capillaries•very thin to facilitate the diffusion of gases

RESPIRATORY MEMBRANE

LUNGS• very thin to facilitate the diffusion of gases•One of the largest organs (by volume)• Each lung is conical in shape with its base restingon the diaphragm and its apex extendingsuperiorly to a point approximately 2.5 cm superiorto the clavicle• 2 surfaces – costal and mediastinal surface• 3 borders – inferior, anterior, posterior

LUNGS• Hilum - region on the medial surface of the lung where structures, such as the main bronchus, blood vessels, nerves, and lymphatic vessels, enter or exit the lung

• Root of the Lung - All the structures passing through the hilum

LUNGS

LUNGS

RIGHT LUNG• Composed of 3 lobes and 2 fissures• Oblique fissure – separates the inferior lobe from the superior lobe and middle lobe

• Horizontal fissure - separates the superior lobe from the middle lobe

RIGHT LUNG

RIGHT LUNG

LEFT LUNG• Composed of 2 lobes and 1 fissure• Oblique fissure separates the superior and inferior lobe

LEFT LUNG

LEFT LUNG

LUNGS

LUNGS• Each lobe is supplied by the lobar bronchus• Lobes are subdivided into bronchopulmonary segments –which is supplied by the segmental bronchi• Bronchopulmonary Segment – smallest functionally independent

region of a lung and the smallest area of lung that can be isolated and removed without affecting adjacent regions

LUNGS

LUNGS

LUNGS• Each lobe is supplied by the lobar bronchus• Lobes are subdivided into bronchopulmonary segments –which is supplied by the segmental bronchi• Bronchopulmonary Segment – area of lung supplied by a

segmental bronchus and its accompanying pulmonary artery branch

• smallest functionally independent region of a lung and the smallest area of lung that can be isolated and removed without affecting adjacent regions

DIAPHRAGM• Musculotendinous organ that seals the inferior thoracic aperture

• Dome-shaped; right dome is higher than the left, reaching as far as rib V

• Separates the thoracic cavity from the abdominal cavity• Responsible for breathing

DIAPHRAGM• As the diaphragm contracts, the height of the domes decreases and the volume of the thorax increases