1. LECTURE EIGHTEEN RESPIRATORY SYSTEM
HUMAN ANATOMY
LECTURE EIGHTEEN
RESPIRATORY SYSTEM

2. FUNCTIONS Gas exchange - (O2 and CO2) in lungs
Regulation of blood pH - alters blood CO2 levels
Voice production - movement of air past vocal cords
Immunity - protection against microorganisms by preventing
entry and removing them from respiratory surfaces
Olfactory stimulation – airborne chemicals enter with
inhalation

3. TERMINOLOGY Ventilation - movement of air into and out of lungs
External respiration - gas exchange between air in lungs
and blood stream
Internal respiration - gas exchange between blood and tissues
Cellular respiration – production of energy (ATP) in the cell

5. RESPIRATORY ANATOMY Upper tract
Nose, nasal cavity, pharynx, and associated structures
Lower tract
Larynx, trachea, bronchi, and lungs
Respiratory mucosa
lines the conducting portion
consists of epithelial cells with
underlying areolar layer (lamina propria)
upper tract layer contains mucosa glands
lower tract layer contains bundles of
smooth muscle cells
Epithelial layer changes:
pseudostratified ciliated columnar cells line nasal cavity and pharynx, and portions of lower tract
smaller bronchioles become cuboidal
with some cilia
alveoli contain simple squamous epithelium

6. NOSE AND NASAL CAVITY
External nose composed of cartilage with bone across the bridge
Nasal cavity extends from nares through to choane (entrance to pharnyx)
- hard palate makes up the floor and
separates nasal from oral cavity
- nasal septum divides left and right
sides
- conchae (3) are bony ridges on
lateral walls to increase surface
area
- meatuses are areas between conchae
- paranasal sinuses are air filled
spaces within bone that open into the
nasal cavity and are lined with mucus
membrane (reduce weight of skull,
produce mucus, influence voice tone)

7. FUNCTIONS OF NASAL CAVITY
- nasolacrimal ducts (carry tears) also enter into cavity
- olfactory receptors found in superior area of nasal cavity
FUNCTIONS OF NASAL CAVITY
passageway for air
trap debris from air:
- coarse hairs within epithelial lining (stratified squamous epithelium)
- pseudostratified columnar epithelium containing cilia and mucus
producing goblet cells - mucus traps debris and cilia sweep mucus to
pharynx (to be swallowed)
air is warmed by nasal capillaries and moistened by mucus
smell
resonating chambers for speech

8. PHARYNX Common passageway of respiratory and digestive systems
Divided into three regions:
Nasopharynx
- internal nares to ulva
- pseudostratified columnar
epithelium with goblet cells
- auditory tubes enter
- contains pharyngeal tonsils
Oropharynx
- ulva to epiglottis
- stratified squamous
epithelium (protects against
abrasion from food)
- palatine and lingual tonsils
Laryngopharynx
- from epiglottis to esophagus
- lined with stratified squamous
and ciliated columnar epithelium

9. LARYNX

10. LARYNX Found below hyoid bone in throat
Consists of nine cartilages (three are unpaired and six form three pairs)
connected by muscles and ligaments
epiglottis is attached to thyroid and has flap near base of tongue (elastic
rather than hyaline cartilage)
largest is the thyroid cartilage (Adam’s apple)
most inferior is the cricoid cartilage – forms base of larynx
Vocal Cords
held together by paired ligaments
- superior pair form the vestibular folds (false vocal cords)
- inferior pair form the vocal folds (true vocal cords)

11. FUNCTIONS OF LARYNX Maintain an open passageway for air movement
Epiglottis and vestibular folds prevent swallowed material from moving into larynx
Vocal folds are primary source of sound production
- greater amplitude of vibration, louder the sound
- frequency of vibration determines pitch

12. VOCAL FOLDS

13. TRACHEA
Extends from the cricoid cartilage of the larynx through the mediastium and divides into the right and left bronchi
Membranous tube of dense connective tissue and smooth muscle (trachealis) supported by hyaline cartilage
16 to 20 C-shaped tracheal cartilage rings open posteriorly - provide protection and maintain open airway
Lined with pseudostratified columnar epithelium with cilia and goblet cells that produce mucus – sweep mucus and debris upward so may be swallowed

14. BRONCHI
Trachea branches in mediastium into right and left primary bronchi
C-shaped cartilagenous rings maintain open airway
Before branching each primary bronchus travels along the medial groove (hilus) of the lung

15. BRONCHIAL TREE
Primary bronchi divide inside the lungs into smaller passageways - secondary bronchi (two in the left and three in the right lung)
Secondary bronchi divide into tertiary bronchi extending to the bronchopulmonary area of the lungs
Walls of secondary and tertiary bronchi have progressively less cartilage and more smooth muscle - diameter decreases
- pseudostratified columnar epithelium with cilia and mucus producing goblet
cells
Tertiary bronchi branch into bronchioles
and finally terminal bronchioles
Terminal bronchioles branch into respiratory
bronchioles ending in alveolar ducts
- open into alveoli (small sacs)
- thin simple squamous epithelium

17. ALVEOLI Each alveoli is surrounded by an extensive capillary network
- capillaries are surrounded by a
network of elastic fibers to hold
alveoli and bronchioles and push
air out
Alveolar epithelium is simple squamous epithelium - thin and very delicate for gas exchange
Roaming macrophages patrol epithelial surface for foreign particles
Septal cells produce superfactant (phospholipids and proteins) - to keep sacs open

18. RESPIRATORY MEMBRANE Site of gas exchange in alveoli Composed of:
(1) squamous cells lining alveoli
(2) endothelial cells lining adjacent
capillary
(3) fused basal laminae between
alveoli and endothelial cells
Allows for quick exchange of O2 and CO2 across membrane

19. LUNGS Each is cone-shaped with: - base resting on diaphragm
- apex extending beyond clavicle
- hilus on medial surface is where
bronchi, blood vessels, nerves, and
lymphatics enter - form root
Divided into lobes (right has three and left has two) separated by deep fissures
Each lobe is divided into bronchopumonary segments separated by a connective tissue septa - supplied by tertiary bronchi
- divided into lobules - supplied by bronchioles

20. PLEURA Lungs sit inside thoracic cavity
Each lung is surrounded by a separate pleural cavity filled with pleural fluid (lubricant holds membranes close together)
Each cavity is lined with a serous membrane called pleura
visceral pleura - adheres to lung
parietal pleura - adheres to thoracic wall

21. THORACIC WALL
Thoracic vertebrae, ribs, costal cartilages, sternum and associated muscles
Thoracic cavity is the space enclosed by the thoracic wall and the diaphragm
Diaphragm separates thoracic cavity from abdominal cavity