Chapter Four Flashcards
The respiratory system allows gas exchange
Mucus lining
- In the nasal cavity and the upper airway
- The epithelial lining contains goblet cells which secrete a clear sticky mucous
- Traps dirt particles and microbes before they enter the lungs
Nasal cavity
- The nose
- Air enters and leaves the body through here
- Air is cleaned, warmed and moistened before entering the body
- Nasal secretions contain an anit-bacterial enzyme (lysozyme)
Larynx
- A box like structure of cartilage
- Where vocal cords are found
- Entrance is protected by epiglottis
Trachea and bronchi structure
C-shaped cartilage that prevent tubes collapsing during inspiration
Upper airways
- Lined with ciliated mucus membrane
- Mucus traps dirt particles and microbes
- Cilia sweep dirty mucus up the trachea and into the throat to be expelled
Bronchi
- The structure splits off into 2, one for each lung
- These further split into secondary bronchi which take air into the lobes of each lung
- These then divide to form bronchioles
Bronchioles
- Split into millions of terminal bronchioles
- No cartilage
- Made up of smooth muscle, allows them to control flow of air into the lungs expanding when needing more oxygen
-Cilia and mucous are also present protecting the lungs from contaminents
Alveoli
- The bronchioles terminate in microscopic clusters of air sacs (alveoli)
- Where gas exchange occurs
- Made of smooth tissue
Purpose of breathing
Exchange O2 and CO2 with the lungs and the air
Inspiration steps
- Diaphragm contracts and flattens
- Intercostal muscles contract and ribs move up and out
- Pleura membrane moves with chest cavity
- Internal space increases as does internal pressure
- External pressure decreases
- Air flow through nose and trachea until pressure is equalized
Expiration steps
- Diaphragm relaxes and rounds
- Intercostal muscles relax to move ribs down and in
- Pleura membrane moves back with the chest cavity
- Internal space decreases so does internal pressure
- External pressure increases
- Air flows through nose and trachea until pressure is equalized
Propeties of alveoli which make it suitable for gas exchange
- Very thin
- Large surface area
- Moist
- Large blood supply
Alveoli > very thin
gas molecules dont have to travel far to move in/out of the blood
Alveoli > large surface area
Many of them which increases surface area which increases the amount of gas that can be exchanged in a short time period
Alveoli > moist
Prevents evaporation of the dissolved gas fluid
Alveoli > large blood supply
Increases the amount of blood in contact with the air in the sacs, it maintains the needed concentration levels in the blood
Oxygen concentration (inspiration)
I- 20.95% E- 15.80%
Carbon dioxide concentration
I- 0.04% E- 4.30%
Oxygen gas exchange
- Blood travels to the lungs
- It has a low concentration of oxygen as it has been used by the bodys cells
- Lower than the amount is inspired
- As a result there is a net diffusion of O2 through the moisture layer out of the alveoli into the blood capillaries
- Blood then travels to the cells of the body
CO2 gas exchange
- Blood travels to lungs
- High concentration of CO2 due to cellular respiration
- Higher than the concentration in the alveoli
- As a result a net diffusion of CO2 into the alveoli from the blood capillary
Respiratory diseases
- Emphysema
- Asthma
- Pneumonia
- Tuberculosis
What happens when alveoli is damaged
- Its ability to efficiently exchange gas is reduced
- Symptoms include > coughing and shortness of breath
Emphysema
- Long term exposure to particles in the air taken into the lungs (exccessively)
- Alveoli lose elasticity, break down and reduce the surface area of the lungs
- Breathing becomes difficult
- Inadequate SA for gas exchange + difficulty in ventilating lungs
- Once lung damage begins it cant be stopped
Pneumonia
- Infection of the lungs via bacteria, viruses and fungi
- Inflammation causes secretion of mucous into the alveoli thus restricting the amount of air they can contain
- SA for gas exchange is reduced
- Breathing is difficult
Tuberculosis
- Infection, usually of the lungs, caused by bacterium mycobacterium tuberculosis
Hygiene and particle spread
- Most infections spread by droplets
- Coughing, sneezing, spitting, may be inhaled by others causing the spread
- Good hygiene practices, washing hands etc, help reduce spread of lung infections
Asthma
- Medical conditions that cause difficulty in breathing due to narrowing of the airways
- Smooth muscles contracting narrowing the airway
- Inflammation causing the lining to thicken and narrow
- Allergic or non-allergic response
Asthma attack
- Dust, pollens, smoke, stress, emotions, medication, animals, cold weather adn some food substances
- Muscles surrounding the bronchioles spasm
- Narrowing of the airways
Steps of the respiratory system
- Nasal/ Oral cavity
- Pharynx
- Larynx
- Trachea
- Bronchi
- Bronchioles
- Alveoli
Alveoli (def)
The air sacs in the lungs
Bronchiole (def)
A very small tube in the lung
Epiglottis
A cartilage flap at the base of the pharynx that covers the trachea during swallowing
Larynx (def)
The structure at the top of the trachea that contains the vocal cords
Pharynx (def)
The throat; the pharynx joins the mouth cavity to the oesophagus and the larynx
Pleura (def)
A membrane covering the surface of the lungs
Pleural fluid (def)
A thin layer of fluid within the pleura that allows the lungs to move during breathing
Primary bronchi (def)
The first branching from the trachea entering the left and right lungs
Respiratory system (def)
The system specialised to facilitate the intake of oxygen and the removal of carbon dioxide
Secondary bronchi (def)
The division of the primary bronchi taking air into each lobe of the lungs
Terminal bronchioles (def)
The end of the bronchioles before they form alveoli
Tertiary bronchi (def)
The division of the secondary bronchi
Trachea (def)
The tube that takes air from the throat to the lungs; the windpipe
Ventilation (def)
The process of inhalation and exhalation
Vocal cord (def)
Membrane in the larynx that vibrate producing sounds
Haemoglobin (def)
A red protein that carries oxygen through the blood
External intercostal muscle (def)
The outermost of the three intercostal muscles that arise from the lower border of the rib above the respective intercostal space
Pleural cavity (def)
The space enclosed by the pleura
Thoracic cavity (def)
A space in the chest that contains organs, blood vessels, nerves and other important body structures
Diaphragm (def)
A dome shaped muscular partition separating the thorax from the abdomen
Intercostal muscles (def)
Groups of muscles that run between the ribs and help form and move the chest wall
Tidal volume (def)
The amount of air that moves in or out of the lungs with each respiratory cycle
Cilia role in respiratory system
Move microbes and debris up and out of the airways
