Chapter 4 - gas exchange and excretion Flashcards
What is gas exchange in humans
The take in of oxygen and the removal of carbon dioxide
Where does gas exchange occur in humans
- In humans, gas exchange occurs in the alveoli in the lungs
- Gas exchange occurs via diffusion
What parts are used to move air in the alveoli
They move alongthe trachea and the bronchi and bronchioles
How does deoxygenated blood move to the alveoli
It moves along capillaries that branch from the pulmonary artery
How does oxygenated blood move from the alveoli
Along the capillaries that join up to the pulmonary vein
How does oxygen diffuse from the alveoli to the blood
- Capillaries lie close to the walls of the alveoli
- oxygen diffuses form the air inside the alveoli into the capillaries
- this occurs because the concentration of oxygen is higher inside the air in the alveoli than in the deoxygenated blood
- Hence there is a diffusion gradient for oxygen, from the alveoli to the blood
Why does carbon dioxide diffuse from the blood into the air inside the alveoli
- Because the concentration of carbon dioxide is higher in the deoxygenated blood than in the air inside the alveoli
- Thereofre, there is a diffusion gradient for carbon dioxide, from the blood into the alveoli
Which features allow maximum gas exchange to occur
Large surface area - faster diffusion
Thin walls - short diffusion distance
Good ventilation with air - so diffusion gradients are maintained
Good blood supply - To maintain a high concentration gradient so diffusion occurs faster
Describe the diagram of gas exchange
Why are the alveoli kept moist
To stop them from drying out
Label this
What is the role of the ribs
Its a bone structure that protect vital organs
What is the role of interocstal muscles
Muscles between ribs which control their movement causing inhalation and exhalation
What is the role of the diaphram
Sheet of connective tissue and muscle at the bottom of the thorax that helps change the volume of the htorax to allow inhalation and exhalation
What is the role of the trachea
It is a windpipe that connects the lungs with the mouth and nose
Role of the larynx
The voice box; when air passes across the larynx a sound is made
What is the role in bronchi
large tubes branching of the trachea with one bronchus for each lung
Role of the bronchioles
Bronchi split to form bronchioles in the lungs which connect to alveoli
What is the role of alveoli
They are tiny air sacs where gas exchange takes place
Features of the trachea and their functions
Rings of cartilidge surround the trachea to provide support for the airways and to keep them open during breathing
What are goblet cells
Cells that secrete mucus
What are cilia cells
Cells covered in tiny hairs called cilia
- They are used to beat and push mucus out of the lungs into the throat