RESPIRATORY SYSTEM(Basic Anatomy)

DR TINKU JOSEPH

DM ResidentDepartment of Pulmonary Medicine

AIMS, Kochi

Email: tinkujoseph2010@gmail.com

Respiratory System starts at the nares

Major Functions

Upper respiratory system:1. Air conditioning (warming)2. Defense against pathogens3. Gas Transport

Lower respiratory system:1. Speech & other

respiratory sounds2. Gas exchange (ventilation)3. Maintenance of

homeostasis, e.g. pH

Respiratory Epithelium

• Histology? Pseudo…

• Mucus produced by numerous goblet cells

• Defense by means of

• filtering hairs

• turbinates

• ciliary escalator

(mucociliary blanket)

• sticky mucus

Respiratory Muscles

Diaphragm: depresses on contraction inhalation

External intercostals: elevate ribs inhalation

Internal intercostals: depress ribs active exhalation

(Accessory muscles - serratus anterior, scalenes, pectoralisminor, sternocleidomastoid, internal and external obliques, transverse abdominus, rectus abdominus)

Upper Respiratory System

1. Nose

2. Nasal Cavity

3. Paranasal sinuses

4. Pharynx

Upper Respiratory System

1) Nose External and internal nares =

Nostrils Nose Hairs = vibrissae Alar cartilages on the nose Paranasal Sinuses

Upper Respiratory System

• 3) Nasal Cavity

• Nasal Conchae:

– Superior, middle and inferior

– Other name: “Turbinate bones” because they create

– Advantage ?• nasal septum• hard palate, soft palate

Upper Respiratory System

3)Paranasal Sinuses

• Named after their bones

– Frontal

– Ethmoid

– Sphenoid

– Maxillary

Upper Respiratory System

4) Pharynx

Shared passageway for respiratory and digestive systemsNasopharynx - part above uvula and posterior to internal

naresOropharynx – portion visible in mirror when mouth is wide

openfauces = the openinguvula - posterior edge of soft palate

Laryngopharynx – between the hyoid bone & the esophagus

Lower Respiratory System = Anything inferior to the Pharynx

Larynx: Cartilaginous cylinder (from C4- C7)

Made up of 9 cartilages– 3 large unpaired (know

these!) Thyroid, Cricoid, and Epiglottis

– 3 small paired (involved in

construction of voice box)

Larynx (voice box)

Hyoid Bone

Epiglottis

Thyroid Cartilage

Adam’s Apple

Cricoid Cartilage

Vocal Folds

Larynx, cont’d

The pitch of sound is from tension of the elastic fibers of the vocal folds

Resonance from shape of pharynx and mouth

The glottis is the opening between the vocal folds

Innervation via laryngeal nerves

Branches of CN X

Left recurrent laryngeal nerve loops around aorta

From Bronchi to Lungs: The Bronchial Tree

1 bronchi (enter lungs at hilus, complete cartilage rings)

2 bronchi (from now on cartilage plates)

3 bronchi

Bronchioles

Terminal bronchioles

Respiratory bronchioles

Alveolar ducts

Alveolar sacs

Conducting portion

Respiratory portion

Lungs

Light, soft, spongy

Conical in shape, apex, base, costal surface, medial surface, hilus. Note various impressions

Right lung

Three lobes; superior, middle and inferior

Oblique and horizontal fissure

Left Lung

Two lobes; superior and inferior also Lingula and Cardiac notch, oblique fissure

Right Lung

Right Lung

Right Lung

Left Lung

Left Lung

Left Lung

Surface Anatomy

Surface Anatomy

Surface Anatomy

Airways

Trachea, primary bronchi, secondary bronchi, tertiary bronchi out to 25 generations

All comprised of hyaline cartilage

Trachea

Begins where larynx ends (about C6)

10 cm long, half in neck, half in mediastinum

20 U-Shaped rings of hyaline cartilage – keeps lumen intact but not as brittle as bone

Lined with epithelium and cilia which work to keep foreign bodies/irritants away from lungs

Airways

Primary Brochi

One to each lung – continuation of trachea Right bronchus is wider and shorter 2.5 cm as opposed to

5 cm and branches from the trachea at a greater angle

Secondary bronchi – one to each lobe, three in right, two in left

Tertiary – one to each bronchopulmonary segment –approximately 10 per lung

All of the above are hyaline cartilage with no ability to change diameter

Bronchoscope

Tumor

Tumor

Tumor

In and Out

Bronchopulmonary Segments

Bronchopulmonary Segments

Bronchopulmonary Segments

Bronchioles

First level of airway surrounded by smooth muscle; therefore can change diameter as in brocho-constriction and broncho-dilation

Terminal

Respiratory

3-8 orders

alveoli

Bronchioles

Bronchioles

Gas Exchange

Pulmonary arteries carry deoxygenated blood to aleoli

Gas exchange occurs via diffusion through the capillary beds

Returned to heart via pulmonary veins

Gas Exchange

Innervation

Pleura via intercostal (thoracic) nerves

Tracheobronchial tree

Parasympathetic via CN X efferent function = broncho-constriction via smooth mm., also to epithelial cells in trachea; afferent = responsible for cough reflex

Sympathetic from T1-T5 efferent = brocho-dilation

Intercostal to Pleura

Innervation

Pleural Cavities and Membranes

Two cavities separated by mediastinum

Lining of cavities

– Parietal Pleura

– Visceral Pleura

– Pleural Cavity

Pleurisy

Pneumothorax, (hemothorax, pyothorax, pleural effusion)