Explain the gross anatomy and functions of the respiratory system.

Discuss the structure and functions of the upper and lower respiratory tracts in detail, including a description of the histology in each region.

Identify the pleural cavities, its membranes and the muscles of ventilation.

Respiratory System Function

Major Functions

Upper respiratory system:1. Air conditioning2. Defense against

pathogens

Lower respiratory system:1. Speech & other

respiratory sounds 2. Gas exchange3. Maintenance of

homeostasis, e.g. pH Fig 24-1

Respiratory Epithelium

Structure?

Mucus produced by ________

Mucus escalator

Defense by means of •filtering hairs•ciliary escalator•sticky mucous

Nasal Conchae

Superior, middle and inferior

Other name: “Turbinate bones” because they create ______

Advantage ?

! Respirator breathing !

Fig 24.3

Upper Respiratory System

1) Nose external and internal nares turbinates or conchae (superior, middle, and inferior) nasal septum hard palate

2) Pharynx - shared passageway for respiratory and digestive systems

nasopharynx - part above uvula and posterior to internal nares oropharynx – portion visible in mirror when mouth is wide open

uvula - posterior edge of soft palate laryngopharynx – between the hyoid bone & the esophagus

Fig 24.3c

Lower Respiratory System

Anything below Pharynx

Larynx: Cartilaginous cylinder (from C4- C7) 

Made up of 9 cartilages– 3 large unpaired (know these!)– 3 small paired (involved in construction of voice box

Stabilized by ??

C3

C4C5

C6C7

Fig 24.4

Trachea

Passageway to lungs (attached via ligament to ?)

Lining ?

Incomplete cartilage rings (C-shaped) - completed by trachealis muscle. Significance?

Annular ligament

Fig 24-7

Tracheal Blockage

oorr

Heimlich Maneuver Heimlich Maneuver or abdominal thrustor abdominal thrust

TracheostomyTracheostomy

From Bronchi to Lungs

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

Fig 24.9

Fig 24.11

Paired Lungs

Situated in _________

Subdivided into lobes (each supplied by 2 bronchus)

Right lung: 3 lobes (rel. broad and short)

Left lung: 2 lobes (long and narrow)

Right and left lung separated by __________

Lung hilus

Why?Fig 24-8

Fig 24-8

Alveolar Organization

Alveoli are site of gas exchange

Close association with capillaries

Lots of elastic fibers in alveolar wall

Alveolar cells Type I cells – respiratory epitheliocytesType II cells – septal cells – produce surfactantAlveolar Macrophages – dust cells – phagocytic

Fig 24-11

Fig 24-12

Respiratory Membrane

Different from respiratory epithelium

Super thin. Made up of 4 layers:

1. epithelium of alveolus 2. its basement membrane

back to back and fused to the

3. basement membrane of capillary endothelium

4. endothelium of capillary

Chronic progressive enlargement of alveoli accompanied by destruction of their wall

Due to prolonged exposure to respiratory irritants (??)

Emphysema

Pleural Cavities and Membranes

Two cavities separated by mediastinum

Lining of cavities?

pleurisy

Pneumothorax

Conducting blood supply to the lungs via bronchial arteries. Venous return to pulmonary veins (consequence ?)

Fig 24-13

Pulmonary Embolism

Causes for development of emboli in veins of legs:

Immobilization

Trauma

Long surgeries

Oral contraceptives

Obesity

Cigarette smoking

Hypertension

See p. 805

Respiratory Muscles

Diaphragm: depresses inhalation

External intercostals: elevate ribs inhalation

Internal intercostals: depress ribs active exhalation

Accessory muscles - serratus anterior, scalenes, pectoralis minor, sternocleidomastoid, internal and external obliques, transverse abdominus, rectus abdominus

Fig 24-14