Respiration and Breathing 1 Flashcards
What are the key events of respiration and breathing.
5 things
(Bob Eats Ten Enormous Icecreams)
Breathing/ ventilation (moving air in and out of lungs). Gas exchange between air in lungs and blood (external respiration: oxygen uptake and carbon dioxide removal). Gas transport around the body. Gas exchange between blood and body cells. Internal respiration (cellular metabolism: oxygen consumption and production of carbon dioxide)
What happens in healthly lungs
They expand to fill the chest cavity
What is the space between the lung and plural membrane called
Intraplural space
What are the components of the upper respiratory tract
Nasal cavity, pharynx, larynx
What are the components of the lower respiratory tract
Trachea, primary bronchus, lungs, diaphragm
What is the purpose of the ribs
To protect the soft mass of the lungs
What are alveoli
The mass of lungs and sight of gas exchange
What is are the functions of the respiratory system
To provide a sight for gas exchange and to maintain normal levels of oxygen and carbon dioxide in systemic arterial blood
Why does the respiratory system provide a sight for gas exchange
Intake of oxygen and for delivery to respiring cells and elimination of Co2 produced by respiring cells
What is normal arterial partial pressure of oxygen
98mmHg/13KPa
What is normal arterial pressure of carbon dioxide
40mmHg/5.3kPa
What is respiration matched to
Metabolism
What are the other functions of the respiratory system
Contributes to regulation of blood pH. Filters, warms and humidifies inspired air. Contains smell receptors. Produces sounds. Metabolism of biologically active chemicals
How does the respiratory system contribute to the regulation of blood pH
Increased CO2 results in acidification of the body. pH must be maintained as enzymes are optimised at specific pHs
Why does the respiratory system filter, warm and humidify air
Filtering air helps protect from harmful products, warming and humidifying air means diffusion takes place faster so helps oxygen uptake
Describe the conducting zone/ dead zone
No gas exchange takes place. Air moves by bulk flow and is conditioned, filtered and warmed. As airways branch the space becomes narrower
Describe the transitional and respiratory zones
Location of respiration, at Z17 alveoli start to appear enabling respiration to take place. Whenever alveoli occur they are encased by a capillary network which enables the delivery of oxygen to blood and removal of CO2
When does ventilation occur
When active muscle force is applied to a relaxed respiratory system
What type of process is inspiration
An active process and so requires ATP
What happens during inspiration
The volume of the thorax is increased, as the diaphragm contracts and flatterns the external intercostal muscles contract.
What is the most important muscle in inspiration
The diaphragm. If there are issues with the diaphragm assistance is needed to breathe
What happens as the volume of the thorax increases
Intrapleural pressure falls. Lungs expand. Alveolar pressure is less than atmospheric pressure (pressure gradient is established). Air flows into lungs until alveolar pressure is equal to atmospheric pressure. Air moves passively due to change in volume
What type of process is expiration
A passive process (so no ATP required)
What happens during expiration
The diphragm and external intercostal muscles relax. The elastic recoil of the lungs and chest walls reduces the volume of the thorax (passive mechanism).
What happens as the volume of the thorax decreases.
Intrapleural pressure rises. Lungs recoil. The pressure of the alveoli is greater than atmospheric pressure. Air is expelled from the lungs
What is used to measure lung function
A spirometer
What is a spirometer
A drum that moves to measure movement, movement data is sent to a computer
What are spirometers useful in
Health diagnostics, measuring the effectiveness of treatment, monitoring disease
What is normal tidal volume
1/2-1/4 of a litre
What is maximum tidal inspiration and expiration
5 litres (10x bigger than normal tidal volume)
During inspiration what resistive forces oppose airflow
Airway resistance. Pulmonary tissue resistance.
Inertia of air and tissues
What is airway resistance
Resistance to movement of air through airways (intrinsic resistance which requires 90% of work done to overcome)
What is pulmonary tissue resistance
Friction between lungs and chest wall
What is inertia of the air and tissues
Coughing or sneezing results in a sudden change from static to dynamic and therefore energy is required to overcome the inertia
During inspiration what resistive forces assist airflow
Elastic recoil of lungs and chest wall. Surface tension in alveoli
What is elastic recoil of lungs and chest wall
The fibres are made from elastin and collagen and therefore are stretchy and recoil after expansion
What is surface tension in the alveoli
The fluid lining of the alveoli dissolves oxygen from gas to aqueous, however oxygen in solution generates more surface tension due to attractive forces of the molecules in the fluid lining and the alveoli, this contributes to ejecting air
