Lecture 1 - Respiratory System Structure Flashcards
What are the 5 functions of the respiratory system?
- Provides extensive gas exchange surface area between air and circulating blood
- Moves air to and from exchange surfaces of the lungs
- Protects respiratory surfaces from outside environment
- Sound production
- Olfactory sense
Define respiratory tract
Passageway carrying air to and from the exchange surfaces in the lungs
What are the different portions of the respiratory tract?
Conducting portion - nasal cavity to terminal bronchioles
Respiratory portion - respiratory bronchioles and alveoli
Or upper (nasal to pharynx) and lower (larynx and down)
In total how many times do the airways branch?
23 - large network of branched passageways
What is an irregular dichotomous pattern?
Each pathway gives rise to 2 pathways
What are alveoli?
Buds in the bronchiole wall from branch 17 then from 20 it is all alveoli
What is the difference between the left and right lung?
Right lung - superior lobe, inferior lobe and middle lobe
Left lung - Superior lobe and inferior lobe - no middle lobe as the heart lies there - allows it to function without friction (cardiac notch)
What is the respiratory mucosa?
It lines the conducting portion of the respiratory system
It has an epithelial layer and an areolar layer
Ciliated - moves upwards towards the top of the tract
What is the lamina propria?
It underlies the respiratory mucosa
It has mucus glands in the upper tract - aiding the mucous ciliar elevator to remove harmful pathogens from the lungs
In the lower tract it has smooth muscle for dilation and constriction
Outline the structure of the nasal cavity
External nares - opening of the nostril
Nasal vestibule - contains nasal hairs which make up the first particle filtration system
Air then flows through the 3 nasal meatuses - controls humidity of the air
Outline the palates
Hard palate - separates the nasal cavity and oral cavity
Soft palate - Extends posterior to hard palate and divides the superior nasopharynx from the lower pharynx
Outline the pharynx
A chamber shared by digestive and respiratory systems
Extends from the internal nares to entrances of larynx and esophagus
3 divisions - nasopharynx, oropharynx and laryngopharynx
Outline the larynx
A cartilaginous structure that surrounds the glottis
What is the epiglottis?
Small moveable lid which protects from food getting down the respiratory tract
Outline the glottis?
Sits inside the larynx
Opening between the vocal folds
Sound and control of pitch
Outline sound production
Sound is produced by air passing through the glottis it vibrates the vocal folds and produces sound waves
Outline sound variation
Tension on the vocal folds
Voluntary muscles
Outline speech
Phonation - sound production at the larynx
Articulation - modification of sound by other structures
Outline the trachea
Bottom of the larynx to first branch of the primary bronchi
Rings of cartilage - aren’t complete to keep the airways open and needs to be flexible for movement
Outline the esophagus
For food
Outline the role of the trachealis muscle
Force of contraction to remove something that has got past the epiglottis and for forced expiration
Outline the primary bronchi
Right and left separated by an internal ridge - carina
Right is larger in diameter and splits more - it descends at a steeper angle as the left has to avoid the heart
These travel to a groove (hilum) along medial surface of the lung
What is the bronchial tree?
Primary bronchi and their branches
Primary branches to form secondary bronchi (lobar) 1 to each lobe
What is the difference between the extrapulmonary and intrapulmonary bronchi?
Extra is the branches outside of the lungs
Intra is within
What are secondary bronchi?
Branch to form tertiary bronchi also called segmental bronchi which supplies air to a single bronchopulmonary segment
The right has 10 and left has 8 or 9
Outline the structure of the bronchi
The walls of primary, secondary and tertiary contain progressively less cartilage and more smooth muscle
Each tertiary bronchus branches into multiple bronchioles which branch into terminal bronchioles
How many terminal bronchioles are formed from 1 tertiary bronchus?
6500
Define bronchodilation
Dilation (widening) of bronchial airways, caused by sympathetic ANS activation, reduces resistance
Define bronchoconstriction
Constriction of bronchi, caused by parasympathetic ANS (autonomic) activation or histamine release (allergic reactions)
Outline the alveoli
Air filled pockets within the lungs
All gas exchange takes place here
Short diffusion distance with 1 cell thick walls
