S2 A&P Respiratory system Flashcards
How does the body obtain oxygen
Oxygen from the air is diffused across the delicate exchange surfaces of the lungs.
It exchanges it for CO2 in the lungs
What is the respiratory system responsible for? (3)
Production of sound
Gas exchange surface area between the air and blood
Participates in olfactory senses
What is the respiratory tract and what does it consist of?
Is the pathway that carries air to surfaces in the lungs for gas exchange,
It consists of a conducting zone that transports the air, and the respiratory zone where gas exchange occurs.
Describe the general structure of the bronchial tree in the lungs
They are a network of branched passageways, that branch a total of 23 times.
They are in an irregular dichotomous pattern – meaning each airway gives rise to two daughter airways
What is the purpose of the irregular dichotomous pattern of the lungs
It allows for a larger number of alveoli, and hence a larger surface area for gas exchange
Where do alveoli appear in the bronchioles?
From Branch 17-20 they are buds in the walls
From 20 onward the whole airway is alveoli
What surrounds alveoli
A dense network of capillaries
Describe the structure of the lungs
Both the two lungs are made of multiple lobes.
Right has 3, whereas the left has 2 and a cardiac notch to allow the heart to sit.
Each lobe is has many individual lobules which are the compartmentalized regions
What lines the conducting portion of the respiratory system
Respiratory mucosa, a mucus membrane
Describe the structure and function of the respiratory Mucosa
Has an epithelial and areolar layer
The epithelia are ciliated, meaning it has hair like structures that beat together moving mucus containing unwanted particles to the top of the tract
What underlines the respiratory mucosa
The lamina propria:
Which in the upper respiratory system contains mucous glands, and in the lower contains more smooth muscle to allow for bronchodilation and bronchoconstriction.
What does air pass through in the nasal cavity
External nares (nostrils)
Nasal vestibule
Three nasal membranes
What happens in the nasal vestibule
Nasal hairs acts as the first particle filtration system
What happens to air in the nasal membranes
The temperature and moistness of the air is controlled before it enters the lungs.
What does the hard and soft palate do?
Hard - forms the roof of the oral cavity and the base of the nasal cavity
Soft - extends posterior to the hard palate and divides the nasopharynx from the lower pharynx
What is the pharynx and its three subdivisions
Is a shared chamber between the respiratory and digestive system. It extends from the internal nares to the entrance of the larynx and the esophogus
nasopharynx
Oropharynx
Laryngopharynx
What does the epiglottis do
Is a smooth lid that protects the top of the pharynx and larynx, preventing unwanted things (like food) getting in.
What is the glottis
Whats known as the voice box, which is the opening between the folds in the larynx. Is involved in sound production and the change in pitch
How is sound produced
From air passing through the glottis, which vibrates the vocal folds and produces sound waves. Tension on the cords allows for sound variation via voluntary muscles.
Describe the structure of the Trachea
Is the trunk of the Bronchial Tree
About 2.5cm in diameter
Extends from the larynx to the top of the bronchi
Is surrounded by C shaped cartilaginous rings.
Why are the Cartilage rings around the Trachea C shaped (3)
To provide rigidity to keep the airway open, whilst providing an element of flexibility.
Gap in C shape can be expanded for easier passage.
Trachealis muscle sits in the gap, which contracts to give large inhalations.
Describe the structure of the bronchi
Is the large air passage that leads from t he trachea to the lungs. The right and left sides are separated by the carina
What is the difference between the right and left bronchi
The right is larger and descends at a steeper angle (as supports more weight as more lobes) than the right
What is the organisation of the bronchial tree
The primary bronchi branch to secondary bronchi to tertiary bronchi which branch into multiple bronchioles with branch to terminal bronchioles that contain bundles of alveoli.
What is the wall of the bronchial tree made from
The walls of the primary, secondary and tertiary contain progressively less cartilage and more smooth muscle. This is to increase the muscular effect on airway constriction and resistance
Describe the structure of bronchioles
They have no cartilage, and are dominated by smooth muscle
They are regulated by autonomic control, which controls the diameter of the bronchioles and airflow resistance.
What is bronchodilation and bronchoconstriction?
Bronchodilation - Is the widening of the bronchial airways by the parasympathetic ANS to reduce resistance
Bronchoconstriction - Is the narrowing of the bronchi, caused by the parasympathetic ANS or the release of histamine
What are alveoli
Air filled pockets within the lungs where gas exchange takes place
What is pulmonary ventilation and what does it cause
The movement of air in and out of the respiratory tract, which provides alveolar ventilation, which is the movement of air in and out of the alveoli
What is Boyles Law
Defines the relationship between gas pressure and volume. Stating that pressure is the inverse of volume of gas.
What is inspiration
How the body allows air into the lungs
It is initiated by the respiratory control center in the medulla oblongata which causes contraction of the diaphragm and intercostal muscles.
How does the diaphragm and intercostals allow for breathing
The diaphragm moves downwards and rotates the lower ribs towards the horizontal plane (1cm in normal, up to 10cm in forced)
The external intercostals move the ribs up and out to increase the size of the thoracic cavity.
What is expiration, and what powers is?
The process of breathing out. It is a passive event done by elastic recoil, powered by the elastic fibres in the connective tissue of the lungs. As well as surface tension of a film of fluid on the alveoli
