Respiration (lesson five) Flashcards
what is the mixture of gas we breathe?
78% Nitrogen, 21% Oxygen, 1% Argon, 0.04% Carbon Dioxide and trace amounts of other gases
do only animals need oxygen?
All plant and animal cells need oxygen to survive
Oxygen is a key reactant in aerobic cellular respiration, the process we use to obtain energy from food
Aerobic Cellular Respiration
- The process by which oxygen is used to obtain energy from food is
called aerobic cellular respiration - 64% of energy is thermal energy: which maintains body temperature
- The remaining 36% is stored energy
- ATP is used by cells to power almost all of their processes
Basic equation
- C₆H₁₂O₆ + 6O₂ ——> 6CO₂ + 6H₂O + energy
- Glucose +Oxygen —–> Carbon dioxide + water + energy (ATP)
Storing Energy
1) Glucose molecules break down releasing energy
2) Phosphorylation: a phosphate is added to a molecule (adenosine diphosphate [ADP])
3) Energy is stored as Adenosine triphosphate (ATP)
4) Cells can then use ATP to power all other functions
ADP + P –ADP phosphorylation–> ATP
how ATP formed
- ATP is formed when energy from the breakdown of glucose is used to attach a phosphate group (Pi) onto a molecule called adenosine diphosphate
(ADP). The process that forms ATP from ADP, phosphate, and energy is called phosphorylation
phosphorylation
- the addition of a phosphate group to a molecule; in aerobic cellular respiration the phosphate group is added to ADP, creating the ATP molecule in which energy is stored
- The process that forms ATP from ADP, phosphate, and energy is called
phosphorylation
ADP vs ATP
ADP has two phosphate groups, and ATP has three
expanded formula for cellular respiration
C6H12O6 + 6O2 + 36 ADP + 36 Pi
—–> 6CO2 + 6H2O + 36 ATP + thermal energy
(glucose + oxygen + adenosine diphosphate + phosphate —–>
carbon dioxide + water + adenosine triphosphate + thermal energy)
How does oxygen get to our cells?
- Gas Exchange: oxygen diffuses into cells, while carbon dioxide diffuses out
Gas exchange in simple organisms
- In simple organisms, this can occur directly through cell membranes to/from the surrounding environment (i.e. Jelly Fish)
gas exchange in complex organisms
In more complex organisms, specialized organs/systems and structures are required
Gas Exchange
- We get the oxygen required for aerobic cellular respiration through gas exchange
- This is the process by which oxygen diffuses into, and carbon dioxide diffuses out of our cells
- In simple organisms, this is done directly through the cell membrane
is gas exchange the same in animals and humans?
- The process is much different for humans and most other large multicellular animals
- This is because they have so many cells in their body that do not come into contact with the environment so they cannot depend on simple diffusion
- They require a specialized organ system to accomplish the same task
where are the two locations where gas exchange can occur?
In humans and other mammals, gas exchange occurs at two locations: the lungs and the body cells
gas exchange in the lungs
- In the lungs, oxygen diffuses from the
air into the bloodstream. - Oxygen is transported through the bloodstream and diffused into all the cells of the body.
gas exchange in the cells
- The cells of all tissues in the body are surrounded by a fluid called tissue fluid (also known as interstitial fluid).
- Oxygen diffuses from the blood into the tissue fluid, and from there into the cells.
- At the same time, carbon dioxide diffuses from the cells into the tissue fluid, then into the bloodstream.
Respiratory Structure
The human respiratory system has 4 important structural features that allow it to function well:
- A thin permeable respiratory membrane across which diffusion can occur
- A large surface area to facilitate gas exchange
- A good supply of blood
- A breathing system for bringing oxygen rich-air into the system
Inhalation (Nose and Mouth)
Air from the outside enters the respiratory system by your nose and mouth
- The air is warmed and moistened in your nasal passage before it enters the lungs which prevents damage to the thin, delicate tissue of your lungs
- The nasal passage is also lined with hairs and mucus to filter out and trap any airborne particles
Inhalation (upper tract)
The air then travels into the pharynx (throat)
- Then, the air will reach the glottis (opening to trachea) and it will NOT be blocked by the epiglottis (the epiglottis will not close, it will be left open to allow the air to enter the trachea)
Your trachea has c-shaped rings of cartilage around it to keep it semi-rigid and open
- It also is lined with mucus-producing cells and cilia (hair like projections) which protect the lungs from foreign matter (by trapping foreign particles and sweeping them upward to be swallowed, coughed, or sneezed out
In the lungs
The trachea branches into two bronchi
- The bronchi then branch off into smaller tubes called the bronchioles
- These tubes end in small sacs called the alveoli which are surrounded by a network of capillaries
- Each alveolus is tiny, and is surrounded by a bed of even tinier capillaries
the lungs
- the lungs are the major part of the respiratory system
- These organs provide the thin respiratory membrane, large surface area, and supply of blood required
- They are contained within your thoracic cavity and are protected by your rib cage
Alveoli
- alveoli allow for maximum surface area for gas exchange
-This is facilitated by the warm, moist, and extremely thin membrane they are made of - This allows for easy diffusion of gases across the membrane and into the blood
Ventilation
- The process of moving oxygen-rich air to the lungs and carbon dioxide-rich air away from the lungs is called ventilation
-ventilation is the process in more complex organisms that ensures a flow of oxygen-rich air to the lungs
what is ventilation based on?
- This process is based on air pressure in the lungs in comparison to the atmospheric pressure
- If Plungs > Patm, then airflow out of lungs
- If Plungs < Patm, then air flows into the lungs
diaphragm
- The thoracic cavity is separated from the abdominal cavity by a sheet of muscle called your diaphragm
- When you inhale, this muscle contracts which shortens and flattens the muscle
- At the same time, your external intercostal muscle between each rib contract which pulls the rib cage up and out
- All these processes act to increase the volume of the thoracic (chest) cavity, which decreases the pressure and causes air to rush into the lungs
pleural membranes
- These are membranes that cover the lungs and line the thoracic cavity
- It is filled with fluid which acts like a lubricant
- outer layer is parietal pleura
- inner layer is visceral pleura
