L02 Respiratory System Flashcards
What is the Larynx?
It connects the back of the nose and the trachea. Also known as the voice box because it contains muscles and ligaments that form vocal chords
Why is the nasal cavity lined with hairs?
Traps dust, pathogens & pollen
What do goblet cells do?
Produce mucus which traps unwanted substances. The mucus also moistens the air inhaled.
Role of the epiglottis
It is a flap of cartilage behind the tongue which prevents food from entering the trachea
What is the pharynx
Connects the nasal cavity to the trachea
Structure and function of the trachea
Made up of C-shaped cartilage (this is so food can still pass in the oesophagus). It supports the trachea structurally to prevent collapse.
Has ciliated epithelium to trap unwanted substances
connects the pharynx to the lungs
Structure and function of Bronchi
smaller in diameter than trachea
c-shaped cartilage
branch from trachea to bronchioles
contain mucus
Structure of bronchioles
smaller in diameter compared to bronchi.
connects bronchi to alveoli
Structure and function of alveoli
Air sacs at the bottom of bronchioles
they have a large surface area
they are moist
they have thin walls (1 cell thick)
excellent blood supply
elastic fibres to withstand pressure
where gas exchange occurs
Role of diaphragm
Muscle that separates the chest from abdomen. Contracts and relaxes to push lungs up and down/ in and out
What are the 3 main processes in the respiratory system
Pulmonary ventilation
Gaseous exchange
Cellular respiration
What is pulmonary ventilation
breathing air into and out of the lungs
What is gaseous exchange
The diffusion of oxygen and carbon dioxide into and out of the blood stream
What is cellular respiration
the process where oxygen and glucose make energy/ATP in cells
Explain what happens in the respiratory system during inspiration
Diaphragm: Contracts + flattens
Lungs: Inflate, volume increases, pressure decreases
External intercostal muscles: contract
Internal muscles: relax
Rib cage: Upwards and outwards
Explain what happens in the respiratory system during expiration
Diaphragm: relaxes
Lungs: deflate, volume decreases, pressure increases
External intercostal muscles: relax
Internal intercostal muscles: contract
Rib cage: Moves downwards and inwards
What is the pleural membrane
two layers of thin membrane.
moist and slippery
contain pleural fluid
prevents friction as the lungs move
If the space between the membranes is punctured the lung on that side will not inflate
What is the role of the pleural fluid
Lubricates the surface of the lungs allowing the layers of membrane to slide over each other.
Allows the lungs to move easily within the chest cavity
How are the alveoli adapted for gaseous exchange
walls are 1 cell thick = short diffusion pathway
surrounded by capillaries = provides concentration gradient
large surface area = large amount of gaseous exchange can take place
Moist = allows oxygen to dissolve before diffusing through alveoli and capillary walls
What is meant by diffusion gradients?
Diffusion: movement of molecules from an area of high concentration to an area of low concentration
particles diffuse down a concentration gradient
capillaries: lower concentration of oxygen than alveoli
so oxygen diffuses from high concentration (alveoli) to low concentrations (blood stream)
What does ATP stand for
Adenosine Triphosphate
Where does cellular respiration take place
Mitochondria
What are the two types of respiration inside cells
Aerobic - needs oxygen
Anaerobic - does not need oxygen
What substrates are required for aerobic respiration
Glucose and oxygen
What is produced during aerobic respiration
32 ATP molecules
carbon dioxide
water
What does anaerobic respiration require ?
glucose
What does anaerobic respiration produce
Lactate and 2 ATP
What is glycolysis
Process in the cytoplasm that breaks down glucose into pyruvate
How many ATP are generated during glycolysis?
2
How many ATP are generated during the electron transport chain?
32
How many ATP are generated during the Krebs cycle?
2
What happens during inspiration?
external Intercostal muscles contract = ribcage up & out
(external intercostal relax)
Diaphragm contracts & flattens
Thoracic cavity increases in volume + volume inside lungs increases
Pressure inside lungs falls below atmospheric pressure so air is drawn in
What happens during expiration?
external Intercostal muscles relax so ribcage returns to normal (internal intercostal contract)
Diaphragm relaxes and returns to dome shape
Thoracic cavity gets smaller, so does the volume of air inside the lungs
Pressure inside lungs increases above atmospheric pressure so air moved out of the lungs
Role of the intercostal muscles
To draw air into and out of the lungs
Brain sends nervous messages to the accessory muscles
Ribcage is attached to spin = contraction of external muscles = ribcage spring up and out
Exam Question
“The organ of the body which adds oxygen to the blood is the lungs…Describe how this happens” [6]
- Gas exchange happens at the alveoli
- Air entering alveoli has high concentrations of oxygen
- Oxygen dissolves in thin moist layer
- Movement occurs due to concentration gradient
- Diffuses across the alveolus and into the capillary
- Oxygen attaches to haemoglobin in RBC
Exam Question
“Identify two purposes of gas exchange” [2]
- To obtain oxygen for aerobic respiration and production of ATP
- To prevent acidic carbon dioxide from building up in the blood and preventing cell activity
Differences between breathing and respiring
breathing is a physical process whereas respiring is a biochemical process
During breathing no energy is released, in respiration energy in the form of ATP is released
There are no enzymes used in breathing but there is in respiration
Breathing is confined to certain organs but respiration happens in all cells in the body.
Why do we need respiration?
Synthesising large molecules
Pumping molecules or ions across membranes by active transport
Moving muscle fibres during contraction
Overview of aerobic respiration
Pyruvate from glycolysis enters mitochondrial matrix via active transport
Pyruvate is broken down into carbon dioxide and water
A large amount of ATP is produced (36 molecules)
Stage 1A: Glycolysis
Cytoplasm + no oxygen
Glucose (6C) gets split into two smaller pyruvate molecules (3C)
ATP and NAD are made
Net yield of Two ATP
Stage 1B: The Link Reaction
Carbon is removed from pyruvate (decarboxylation) = acetate
Acetate is oxidised (removal of hydrogen)
NAD molecules accept the hydrogen forming NADH
Acetyl group binds with coenzyme causing acetyl coenzyme A
Stage 2: Krebs cycle
Mitochondrial matrix
Each complete cycle results in the breakdown of an acetyl group
Carbon dioxide is produced
32 ATP produced
NADH & FADH2
Stage 3: Electron Transport Chain
Cristae of mitochondria & requires oxygen
Uses hydrogen atoms collected by the coenzymes
Hydrogen atoms split into hydrogen ions and electrons
High energy electrons are used to make ATP
Energy is released as electrons pass through a series of carriers
At the end of the ETC electrons join hydrogen ions and oxygen to form water
Key points of anaerobic respiration
Less efficient
Happens during exercise when oxygen is not readily available
No oxygen means there’s no final receptor of electrons do Krebs and ETC do not happen
Lactic acid is poisonous and builds up in muscles causing fatigue and cramp
“oxygen debt” = continue to breathe deeply after exercise for a short period of time
Lactic acid converted back to glucose by the liver but this requires oxygen
Exam Question:
“Outline the role of oxygen in providing the cells with energy” [6]
- Used in oxidative phosphorylation
2.Oxygen accepts electrons at the end of ETC - also accepts hydrogen ions to form water
- Allows ATP production
- Allows a high yield of ATP from glucose in respiration
- Needed for aerobic respiration
What is asthma?
A chronic lung disease which is caused by the inflammation of bronchi. It was be worsened/ triggered by contact with allergens. This makes the airways narrow because the muscles around them tighten.
Biological causes of asthma
Smoking
Dust
Allergens such as pollen
Respiratory infections
Physical activity
Cold air
Lifestyle changes/ impacts with asthma.
Do not smoke + avoid socialising with other smokers
Pollen: Keep windows closed during summer
Dust: Clean house regularly
Air pollution: not going out in smog warnings or in congested traffic
Pet hairs: Avoid pets
Do not go out in the cold
Biological Causes of emphysema
Smoking
Chemical fumes
Respiratory infections
Impact of emphysema
Destruction of alveoli
Less surface area for gas exchange
Less oxygen obtained
Lack of energy
Immobility & wheelchair needs
One story house needed
Oxygen cylinder to help with breathing
Requirement of more home help
Biological cause of cystic fibrosis
A defective gene
impact of cystic fibrosis
Mucus is sticker & thicker than usual
Problems with breathing because of mucus blockages
Chest infections as pathogens get trapped in airways
Lack of oxygen due to impaired gaseous exchange
