respiratory system Flashcards
Nasal Cavity:
Hairs filter dust, pollen and other particles
Air is warmed and moistened
Pharynx:
Commonly known as the throat
Connects the nasal cavity to the larynx
Larynx
Commonly known as the voice box
Has rigid walls of cartilage
Connects the pharynx to the trachea
Trachea
Commonly known as the wind pipe
Is surrounded by rings of cartilage
Branches into the left and right bronchi
Epiglottis
Small flap of cartilage that allows food to pass into the stomach and not into the lungs
Lungs
The lungs are an organ that allow oxygen to be drawn
into the body
You have a left and right lung
Bronchi
Bronchi branch off from the trachea and carry air into the lungs. They branch off 25 times.
Bronchioles
Bronchioles are small airways that extend from the bronchi
they are about 1mm in diameter
They connect the bronchi to the alveoli
alveoli
Alveoli are a mass of tiny air sacs
There are about 300,000,000 alveoli in each lung
Gaseous exchange happens at the alveoli and capillaries
Diaphragm
Is a flat muscle that is located beneath the lungs
The muscle is involved in inspiration and expiration
Thoracic Cavity
This is the chamber in the chest that is protected by the ribs and sternum (thoracic wall)
Internal Intercostal Muscles
Muscles lie inside the ribcage
They draw the ribs downwards and inwards
External Intercostal Muscles
Muscles lie outside the rib cage
They draw the ribs upwards and outwards
Inspiration
. internal intercostals relax, external contract
. diaphragm contracts, flattens, and external intercostal muscles raise the ribs upwards and outwards
. increases volume of thoracic cavity= decreases pressure in lungs compared to outside= air forced into lungs
. when exercising: scalenes muscle, sternocleidomastoid muscle and pectoralis major/minor all contract to help expiration
Expiration
. external intercostals relax, internal contract
. diaphragm relaxes, raises up, and the internal muscles contacts they lower the ribs downwards and inward
. decreases volume of thoracic cavity= increased pressure in lungs to outside= air forced out
. exercise: abdominals and internal intercostals contract to help with expiration
gas exchange
O2 passed down respiratory system to alveoli. O2 diffuses out of alveolar epithelium into the dense capillary network surrounding it (blood- attaches to haemoglobin). It is now in bloodstream, so O2 can travel where needed in body.
at muscles, oxygen in capillaries exchanges with CO2, so myoglobin will pick it up and transfer to mitochondria.
At the same time, CO2 (deoxygenated blood) passes from capillary into alveolus, ready to be breathed out.
Inspiration= O2 breathed in, diffuses from alveoli to bloodstream
Expiration= CO2 from bloodstream (byproduct of respiration) diffuses into alveoli and breathed out
Has plentiful blood supply= more efficient exchange
Large SA for diffusion of gases = due to many alveoli/ capillaries and very small
Moist lining of alveoli = assists diffusion of O2 into blood as some blood dissolves here and so passes into plasma as a dissolved substance = efficient
Thin alveolar/capillary walls (1ct) = short diffusion pathway= efficient
simple diffusion across the respiratory membrane as blood entering the capillaries from the pulmonary arteries has a lower oxygen concentration and a higher carbon dioxide concentration than the air in the alveoli. So O2 diffuses from higher O2 conc in alveoli to low O2 conc in capillary, and CO2 diffuses from high CO2 conc in capillary to lower CO2 conc in alveoli.
Tidal Volume
Is the amount of air inspired or expired in a normal breath when the person is at rest
On average it is 0.5 litres
Vital Capacity
Is the volume of air that can be forced out the lungs after maximal inspiration
Vital capacity can be as much as 4.8 litres
Residual Volume
Is the amount of air left in the lungs even after forced breathing out
This volume of air cannot be breathed out
It prevents the lungs from collapsing
Average volume is 1.2 litres
Total Lung Capacity
Is the vital capacity + residual volume
Average volume is 6.0 litres
Pulmonary Ventilation
The process of moving air in and out of the lungs is called pulmonary ventilation
Minute Volume
The passing of air through the lungs in one minute is known as minute volume
Breathing and exercise
. exercise= more 02 needed for ATP= breathing rate needs to increase
. The medulla oblongata is responsible for involuntary functions such as breathing
Responses of the respiratory system to exercise: Increased Breathing Rate
. exercise= more O2 demand= CO2 levels increase= breathing rate increases
. more intense exercise = increased breathing rate
. stop exercise = breathing rate slows
. Prior to exercise = anticipatory rise in breathing rate
Responses of the respiratory system to exercise: Increased Tidal Volume
. tidal volume increased due to O2 demand
. = more air to pass through the lungs (pulmonary ventilation)
. = O2 goes to working muscles
. = tidal volume increases for both aerobic and anaerobic exercise
Adaptations of the respiratory system to training: Increased Vital Capacity
Training will increase vital capacity
An increase in vital capacity will mean there will be a more efficient supply of oxygen to the working muscles
Adaptations of the respiratory system to training: Increased Strength of Respiratory Muscles
Training will increase the strength of the diaphragm and intercostal muscles
A stronger diaphragm and intercostal muscle will increase the chest cavity allowing more oxygen to be taken into the lungs
Adaptations of the respiratory system to training: Increased Oxygen and Carbon Dioxide Diffusion Rate
Due to the increase in capillaries there is an increase in efficiency of the diffusion of gasses
More oxygen can be delivered to the working muscles
More carbon dioxide can be removed and exhaled
Additional factors affecting the respiratory system: Asthma
Asthma = condition whereby the airways of the respiratory system become restricted
Asthma = the bands around the airways contract and tighten = air cannot move
freely in or out of the body, phlegm can also narrow the airway further
Exercise can induce an asthma attack
Asthma reduces performance = restricts oxygen getting to the working muscles
Exercise can benefit someone with asthma = can reduce the effects by increasing
respiratory muscles, vital capacity and the oxygen and carbon dioxide diffusion rate
Additional factors affecting the respiratory system: Partial Pressure/Altitude
. Oxygen moves from high pressure (alveoli) to low pressure (capillaries) until the pressure are equal
. The greater the difference in gasses, the faster the rate of diffusion
. At altitude there is less oxygen reducing the partial pressure = you have to work harder this can cause: shortness of breath, dizziness and difficulties in concentration
. lack of oxygen altitude = hypoxia which causes an increase in breathing rate and depth
. Performance levels at altitude will reduce, however over a period of time your respiratory system will adapt
. Elite athletes will train at altitude so their body adapts = include an increase in red blood cells & capillaries which will allow more oxygen to be carried and diffused to the working muscles
neural control
- involuntary (controlled by respiratory centre = medulla oblongata and Pons)
- voluntary (cerebral cortex = holding breath/deliberately hyperventilating)
- two areas: (DRG) Dorsal respiratory group and (VRG) Ventral respiratory group. They are responsible for the ‘rhythm generation’ that allows rhythmic and continuous breathing.
chemical control- when active
- chemoreceptors receive info about chemicals in blood. Located in Medulla Oblongata, Carotid arteries or aortic arch
- change in CO2 conc (increases when exercising, so breathing rate increases so can remove CO2 faster)
- change in pH activity (exercise means lactic acid builds up, pH decreases, breathing rate increases, lactate breakdown faster)
- During inhalation, signals increase frequency, diaphragm and external intercostals contract more forcefully.
- during exhalation, internal intercostals are recruited to actively pull the rib cage down.
- these responses allow for greater minute ventilation (vol of air breathed in per min)
Explain why gaseous exchange of oxygen is faster at the alveoli during exercise than at rest. (4)
Muscles are using more O2 (1) therefore a lower partial pressure/ppO2 in the capillaries near the alveoli (1). There is an increased breathing rate (1), which means more O2 /higher partial pressure/ppO2 is in the alveoli (1) which creates a steeper diffusion gradient (1) and O2 moves quicker (from the alveoli) into the blood/capillaries (1)
Name the structures, A–C, described in Table 1.
A flap of cartilage at the base of the tongue, which
prevents food from entering the windpipe.= Epiglottis
Large single tube strengthened by rings of
cartilage = Trachea
Tiny airways that carry oxygen to the alveoli. = Bronchioles
Explain the role of the diaphragm during inspiration and expiration.
When inspiring/breathing in the
diaphragm contracts/flattens/is
forced downwards (1) to increase the
size/decrease the pressure of the
thoracic cavity (1)
When expiring/breathing out the
diaphragm
relaxes/rises/domes/moves up (1)
to decrease the size/increase the
pressure of the thoracic cavity (1)
(a) State the meaning of the term ‘tidal volume’.
The volume of air breathed in and out
with each breath (1)
