1. Flashcards
Breathing:
mechanical process where air moves in and put out the lungs
Gaseous Exchange:
Oxygen and carbon dioxide go across a gaseous exchange surface
Cellular Respiration:
gradual release of energy from organic compounds with O2 present
Necessities of Gaseous Exchange:
》respiratory system is to absorb O2 from atmosphere making it available to cells for respiration
》CO2 is released by cells during respiration and is continously removed during gaseous exchange
》CO2 concentration in the body can dangerously lower the pH in bodily fluids
Requirements for an effective gaseous exchange system:
》must be large to maximise gaseous exchange
》thin- quick and easy diffusion
》moist- O2 & CO2 must be in a solution so it can be diffused through a surface
》transport system- efficient transport of gases
》well protected- fragile & thin
Human Gaseous Exchange:
What do the air passages do and consist of?
》transportation of air to and from lungs
》nasal passages, pharynx, trachea, bronchi, bronchioli
What are the nasal cavities and what do they do?
》the 2 external nostrils lead to the 2 nasal cavities that are separated by a septum
》small hairs in the nasal cavities filtration largest particles from inhaled air
》they are divided into 3 passages by 3 curved turbinate bones
》lined with a mucous membrane (ciliated columnar epithelial cells)
• richly supplied with superficial blood capillaries that warm incoming air
What are goblet cells?
》secrete mucous
》traps dust and germs
》an antiseptic and prevents inhaled germs from multiplying
》moistens incoming air and prevent gaseous exchange surfaces from drying out
What do the cilia do?
》perform sweeping movements in the direction away from lungs, therefore dust carrying mucus is expelled to the outside
Pharynx:
》nasal cavities open into pharynx
》has 2 openings:
• glottis leading to the trachea
• oesophagus aka gullet
Trachea:
》a long, tubular structure (+/- 12cm) infront of the oesophagus
》larynx aka voice box houses the vocal chords which is located at the top of the trachea
》lined with ciliated columnar epithelial tissue that secrete mucus
》C-shaped cartilage rings
• covered with involuntary muscle tissue
Larynx:
》a 🔺️ cartilage box
》top of larynx, a thin leaf-shaped structure (epiglottis)
What does the epiglottis do?
》closes the glottis during swallowing
》prevents food from entering the trachea and choking
How does the involuntary muscle assist the oesophagus?
allows it to expand when food moves down
What happens when dust particles and germs enter trachea?
trapped in mucus and is moved to the pharynx by a sweeping action of cilia = coughing or swallowing
How is the trachea divided?
》Into the R and L bronchus
》entering the R and L lung
What is the bronchi lined with?
a mucous membrane
What are the bronchi held open by?
O-shaped cartilage rings
What does the bronchi divide into?
smaller branches
What happens when they become smaller branches?
they lose their cartilage and form bronchioles
Group of alveoli:
infundibulum (each bronchioli ends with one)
Adaption:
Nasal cavities have hairs
Function:
filters larger dust particles from inhaled air
Adaption: AIR PASSAGES
Richly supplied with superficial capillaries
warms incoming air
Adaption:
Goblet cells that secrete mucus
》traps dust and germs
》antiseptic- prevents multiplication of pathogens
》moistens incoming air- prevention of G.E. drying out
Adaption:
Cilia perform sweeping movements
carries dust-and-germs-carrying mucus outside
Adaption:
Opening to the trachea walls supported by C-shaped cartilage rings
supports and keeps trachea open
Adaption:
‘Open’ sides of C-shaped rings in contact with oesophagus
ability to stretch its walls when ingesting food
EXTERNAL STRUCTURE:
Lungs
》surround and protected by 12 pairs of ribs
》intercostal found between ribs
》R lung- 3 lobes
》L lung- 2 lobes
》Spongy & elastic
What is each lung surrounded by?
a double membrane aka the pleura
What lies between the double membrane and its functionality?
》intrapleural fluid
》prevention of friction when contracting and expanding
Why are the lungs conical?
there is a dome-shaped muscle plate that is situated at the bottom, aka the diaphragm
What epithelial tissue is surrounded by the alveoli?
squamous
Alveoli is surrounded by…
capillaries
What are the capillaries surrounded by?
1 layer of squamous epithelial tissue, aka endothelium
When pulmonary arteries enter the lungs, what do they branch out into?
smaller arterioles to form a network of capillaries around the walls of the alveoli
When the capillaries unite…
they form venules flowing into larger veins > pulmonary veins, which leave the lungs
Adaption:
Bronchioli ends with millions of alveoli
Function:
increase G.E. surface
Adaption:
Alveoli are surrounded by a network of blood capillaries
Function:
transportation of O2 to tissues and CO2 to lungs
What is ventilation of the lungs?
mechanism of breathing
Why is there a movement of air between the atmosphere and lungs?
difference in air pressure between atmospheric air and air in the thoracic cavity and lungs
What are the respiratory muscles?
》diaphragm
》intercostal muscles
Inhalation:
Air from environment > lungs
Exhalation:
Air from lungs > environment
When we inhale…
》diaphragm contracts
》thoracic cavity enlarges from T > B
》external intercostal muscles contract
》ribs ‘expand’
》thoracic cavity enlarges extensively
》abdominal muscles relax so the abdominal cavity can accommodate the viscera (internal organs) bring pushed down by the diaphragm
》T.V.- increases
》P- decrease
》elasticated lungs EXPAND
What is inhalation?
an ACTIVE process associated with the contraction of the diaphragm & external intercostal muscles = increasing of thoracic cavity volume
When we phewwww…
》diaphragm chills out, returning to its original dome shape
》thoracic cavity ↓
》external intercostal muscles relax
• ribs move ↓ & →←
》 thoracic cavity reduces all round
》T.V.- reduced
》P- increase
》CO2 rich air flows put the lungs
What is exhalation?
a passive action associated with the relaxation of the diaphragm and external intercostal muscles = decreasing volume of the thoracic cavity
What happens when we 😮💨 or 😪 ?
》Exhalation becomes an ACTIVE process
Why does exhalation become active?
》internal intercostal muscles contract = ribs →←
》abdominal muscles contract and the intestines ads pushed up against the diaphragm forcing it further ↑
》volume of the thoracic cavity ↓
》pressure within the chest significantly ↑
ALVEOLI:
How does the exchange of O2 work?
》 the inhaled air in the alveoli has a higher O2 concentration in the blood in the surrounding blood capillaries. A diffusion gradient is therefore created between the air we only and the blood in the capillaries. CO2 dissolves in a thin layer of moisture that lines the alveoli and diffuses through the thin walls of the squamous epithelium of the alveoli and the endothelial walls of the capillaries into the blood
ALVEOLI:
Explain the exchange of CO2?
》blood that reaches the alveoli from the tissues has the highest CO2 concentration is an air in the alveoli.
》the diffusion gradient is fearful created between the blood in the capillaries and the air in the alveoli
》CO2 diffuses from the blood into the capillaries through the end of the walls of the capillaries and the squamous epithelial walls of alveoli into the air of the alveoli
TISSUES:
How does the exchange of O2 work?
》oxygenated blood reaches the tissues
》blood in the capillaries have a higher concentration of O2 then cells of the tissues
》diffusion gradient is therefore created between the blood in the capillaries and cells
》O2 diffuses through the endothelial walls of the capillaries into tissue fluid surrounded by cells and into cells
TISSUES:
How does the exchange of CO2 work?
》cells have a higher concentration of CO2 than blood in capillaries
》diffusion gradient is therefore created between the cells and blood in capillaries
* CO2 is released during cellular respiration
》CO2 diffuses from the cells into tissue fluid and then diffuses into the blood of the capillaries
How is O2 transported?
》 majority of O2 that is diffused from the air in the alveoli to blood in capillaries combined with haemoglobin in red blood cells to form oxyhaemoglobin
What dissolves in blood plasma?
A very small portion of O2
How is CO2 transported?
》 most of CO2 that diffuses from the cells into the blood of the capillaries combined with H2O to form carbonic acid which dissociates and is transported as bicarbonate ions
What is the combination of CO2 and haemoglobin called?
carbaminohaemoglobin
What is dissolves into the blood plasma?
A small portion of CO2
When we exercise our body, it requires a larger amount of O2 and respiration and more energy, therefore resulting in excess CO2. What would have to be altered for inhaling more O2-rich air and releasing CO2-rich air?
》increase in rate and depth of breathing
》the heart rate also accelerates
What is the medulla oblongata?
a section of the brain which helps control the breathing rate
The respiratory centre sends…
nerve impulses to respiratory muscles to
1. accelerate
2. decelerate
3. contract
4. relax
What is also known as the medulla oblongata?
the cardiovascular centre
What does the cardiovascular centre do?
controls heart rate
The cardiovascular centre sends…
netve impulses to the heart muscle to:
1. accelerate
2. decelerate
3. contract
4. relax
What is lung capacity?
refer to the TOTAL volume of air that the lungs can accommodate
A human lung can capacitate about…
5 ℓ (5000 cm³)
Amount of air breathed in and put during NORMAL breathing is…
tidal volume
What is inspiratory reserve volumn?
after normal inhalation and breathing in additional air
What is expiratory reserve volume?
breathing out addition air after a normal exhalation
What is vital capacity?
the two reserve volumes as well as the tial volume
What is residual volume?
after the full expiratory reserve volume has been exhaled BUT there is still air in the lungs
With inhalation, fresh air mixes with…
residual volume
When times for a demand of O2 increases…
》the tidal volume increase by using the reserve air volume to get fresh air into the lungs
》results= depth and rate of breathing ↓
》 can be determined before and after exercise by measuring the tidal volume before and after exercise
HOMEOSTATIC CONTROL:
What is sensitive to the changes of CO2 concentration in blood?
Chemoreceptors in the wall of the aorta and the absence of the jugular arteries
HOMOSTATIC CONTROL:
When CO2 concentration increases…
the chemoreceptors send nerve impulse to the respiratory and cardiovascular centres in the medulla oblongata of the brain
HOMOSTATIC CONTROL:
What does the respiratory centre do?
sends nerve impulses to the heart muscle and arterioles
HOMOSTATIC CONTROL:
Why is more CO2-ladsn air exhaled?
rate and depth of breathing ↑
HOMOSTATIC CONTROL:
What does the cardiovascular centre send?
nerve impulses to the heart muscle and arterioles
HOMOSTATIC CONTROL:
Heart rate ↑…
the arterioles constrict and blood flows faster
HOMOSTATIC CONTROL:
CO2 is transported to the lungs faster…
where it can be inhaled
HOMOSTATIC CONTROL:
Therefore, the CO2 in the blood…
returns to normal
What is the effect of altitude on gaseous exchange?
》 with an increase in altitude atmospheric pressure drops, and so does the amount of oxygen in the atmosphere
》people living at a high-altitude usually have more red blood cells to transport a maximum amount of O2 effectively
》if a person living at sea level goes to an area high above sea level for a while, his or her body will adapt after a few days or even weeks and produce red blood cells
》 the O2 carrying capacity of the blood is increased
》 it is especially important for athletes living at the coast to plan to participate in a competition at high altitude to arrive at high altitude in Avon this gives his or her body is not time to adjust if the athlete’s body does not have enough time to adjust he or she with higher very quickly heal her body will have you too few red blood cells to carry enough O2 the muscle tissues for respiration and consequent energy released
