B2 Respiratory System Flashcards
How is trachea adapted for it’s function?
Has rings of cartilage for support so it does not collapse
List the order of the structures air passes through in the respiratory system.
Trachea to the bronchi to the bronchioles to the alveoli
What type of tissue is the diaphragm?
Muscle
What type of cells line the trachea, bronchi and bronchioles?
Ciliated epithelial and goblet cells
What cells make up the alveoli?
Squamous epithelial cells
Why do the surface of alveoli have to be moist?
So oxygen can dissolve in the water before it can diffuse into the blood capillaries.
What 2 things maintain the steep concentration gradients between blood and alveoli?
- Ventilation
- blood flow through capillaries.
What gives a large surface area to alveoli?
Many small alveoli
What happens during inspiration? (4marks)
o external intercostal muscles contract to raise rib cage up and out
o diaphragm contracts and flattens
o increase in volume of the thoracic cavity reduces pressure in lungs
o so air enters, from outside, down the pressure gradient
What happens during expiration?
o external intercostal muscles relax so rib cage moves down and in
o internal intercostal muscles contract to pull ribs down and in during forced expiration
o diaphragm relaxes and domes
o decrease in volume of the thoracic cavity increases pressure inside lungs
o air is forced out down the pressure gradient, aided by the elastic recoil
When are ventilators used to assist breathing?
- When there is muscle weakness
- In severe lung infections
What are pleural membranes in the lungs ?
o are serous membranes
o one side lines body cavity wall and the other lines lungs
o secrete serous fluid that reduces friction and enables the membranes to slide over each other
o prevent lungs adhering to body cavity wall
What do goblet cells produce?
Mucous
What does the elastin in the walls of the alveoli allow to happen?
Allows stretch and recoil.
What is the benefit of the squamous epithelial cells of the alveoli being flat and only one cell thick?
Gives a short diffusion distance for gas exchange
What 3 principles relate to a good and efficient gas exchange in the human lung?
o short diffusion pathway
o large surface area
o maintaining diffusion gradients
Why is oxygen needed in cells?
Aerobic respiration for the production of ATP
What is a peak flow meter used for?
o measure the maximum speed of expiration, known as peak expiratory flow rate (PEFR)
o measure the ability to breathe out air and can monitor degree of obstruction in airways
o are used to determine lung functionality and the severity of asthma and emphysema symptoms
What does PEFR stand for?
Peak expiratory flow rate
What causes the peak expiratory flow rate (PEFR) to vary?
Age
Gender
Fitness levels
What is forced vital capacity?
The amount of air that can be forcibly exhaled after a deep breath in.
What can the measurement of forced vital capacity (FVC) help to determine?
The presence and severity of lung disease, such as asthma, bronchitis, emphysema and chronic obstructive pulmonary disease
What causes the forced vital capacity (FVC) to vary?
Age
Gender
Fitness levels
How does exercise effect tidal volume and breathing rate?
Tidal volume increases during and just after exercise.
Breathing rate increases during and just after exercise.
