Ch 11 - (Gas Exchange in Humans) Flashcards
What are the features of gas exchange surfaces?
- Large surface area: To allow faster diffusion of gases across the surface
- Thin walls: To ensure distance diffusion is shorter
- Good ventilation with air: To maintain diffusion gradient
- Good blood supply: Maintain a high concentration gradient so diffusion occurs faster.
Description of ribs
Bone structure that protects the internal structure lungs
Description of intercoastal muscles
muscles between the ribs that control their movement causing inhalation and exhalation
Description of trachea
windpipe that connects the mouth and nose to the lungs
Description of larynx
also known as the voice box, when air passes across here we are able to make noise.
Description of bronchi
large tubes branching off the trachea with one bronchus for each lung
Description of bronchioles
split to form longer tubes that connects to the alveoli
Description of alveoli
tiny air sacs where gas exchange takes place
Description of diaphragm
sheet of connectives tissue and muscles at the bottom of the thorax that helps change the volume of thorax to allow inhalation and exhalation.
What is present when we breathe in and out?
- When we breathe out contains more water vapor.
- Temperature of exhaled air is higher
What is the composition of inspired air in the following:
a) Oxygen
b) Carbon dioxide
c) Nitrogen
a) Oxygen - 21%
b) Carbon dioxide - 0.04%
c) Nitrogen -78%
What is the composition of expired air in the following:
a) Oxygen
b) Carbon dioxide
c) Nitrogen
a) Oxygen - 16%
b) Carbon dioxide - 4%
c) Nitrogen - 78%
What is the effect of exercise on breathing?
Increases the frequency and depth of breathing.
How can the effect of physical exercise effect on breathing.
By counting breaths taken during one min at rest and measuring average chest expansion for 5 breaths
What are the 2 intercoastal muscles?
- Internal intercostal muscles (found inside the ribcage)
- External intercoastal muscles (found outside the ribcage)
What is a cartilage?
A structure that surrounds the trachea
What is the function of the cartilage?
- Supports the Airways
- Keeps them open during breathing
If not present:
- Sides could collapse inwards
- air pressure inside the tubes drops
What is a diaphragm?
A thin sheet of muscles that separates the chest cavity from the abdomen.
What is the diaphragm responsible for in breathing?
Controlling ventilation
What happens to the diaphragm when you breathe in?
- Diaphragm contracts and it flattens
- This increases the volume of chest cavity
- Decrease in air pressure
- Draws air in
What happens to the diaphragm when you breathe out?
- Diaphragm relaxes and moves upward into dome shaped
- Decreases the volume of chest cavity
- Increase in air pressure in the lungs
- Draws air out
How do the external and internal intercoastal muscles work while breathing?
Work as antagonist pairs (they work in different directions to each other)
What happens during inhalation?
- External set of intercoastal muscles contract
- pull the ribs up and out
- Increases the volume of chest cavity, that decreases air pressure.
- forces air to move in
What happens during exhalation?
- Set of internal coastal muscles relaxes,
- ribs drop down and in
-decreases the volume of chest cavity, increasing air pressure
- forces air to move out
What is the composition of oxygen in inspired and expired air?
Inspired air = 21%
Expired air = 16%
why is the composition of oxygen in inspired and expired air different ?
- O2 is removed from the blood by respiring cells so blood returning to lungs has a lower O2 concentration than air in the alveoli.
What is the composition of carbon dioxide in inspired and expired air?
Inspired air = 0.04%
Expired air = 4%
why is the composition of carbon dioxide in inspired and expired air different ?
- CO2 is produced by the respiration in the cells
- blood transports the CO2 to the lungs where it diffuse into the alveoli as it is in a higher concentration in the blood than the alveoli.
What is the composition of water vapour in inspired and expired air?
Inspired air = lower
Expired air = higher
why is the composition of water vapour in inspired and expired air different ?
- Water evaporates from the moist lining of the alveoli into the expired air as a result of the warmth of the body
What is the composition of nitrogen in inspired and expired air?
Inspired air = 78%
Expired air = 78%
why is the composition of nitrogen in inspired and expired air different ?
nitrogen gas is very stable and cannot be used by the body, it’s concentration does not change.
Why does the sequence and depth of breathing increase when exercising?
- Muscles are working harder and respiring more aerobically
- need more oxygen to be delivered to them.
- to keep up with the energy demand.
What happens when energy demand cannot be met?
Respire anaerobically producing lactic acid
After exercise has finished, what needs to be done?
- Lactic acid needs to be removed
- It lowers the pH of cells and denatures enzymes catalyzing cell reactions.
How can lactic acid be removed?
By combining with oxygen
- repaying the oxygen debt
How can we test if lactic acid is still in our body?
By seeing how long it takes for breathing rate and depth to return to normal.
The longer it takes, the more lactic acid is produced during exercise and the greater the oxygen debt that needs to be repayed.
What increases in muscle cells when exercising?
Rate of respiration
What is a product of respiration?
CO2
CO2 level increases in the cells
What is the process for increasing breathing mechanism during exercise?
- CO2 diffuses out of the cells into the blood plasma
- CO2 drops in pH and becomes acidic
- Blood flows around circulatory system
- Increases CO2 concentration is detected by chemoreceptors in the brain
- Brain sends nerve impulses to the diaphragm and intercostal muscles to increase the rate and depth of muscle contraction.
- The rate of inspiration increases, with the volume in and out
What is the passage down the lungs lined with?
Ciliated epithelial cells
What does the cilia help do?
- Push mucus up the passage towards the nose and throat
- Traps particles, pathogens like bacteria or virus, and dust prevents them from getting into the lungs and damaging the cells.
What is the mucus made by?
Goblet cells
What are chemoreceptors?
cells that detect chemical changes in the body
What do the chemical receptor detect?
change in blood gas level , and change in pH
Located in medulla oblongata
