Midterm 1 Flashcards
What is homeostasis??
It is the relatively stable condition of ECF that results from regulatory system actions
What are the factors that effect homeostasis regulation?
Concentration of nutrients, O2/CO2, waste products, pH, water, salt, electrolytes, plasma, blood pressure and temperature.
What is a feedback system?
It’s response counteracts the initial stimuli, at the body level effecting tissue, organs and cells.
What is a feedforward system?
It is an anticipatory response, and primes the body for challenges to come/ fight or flight.
What is positive feedback?
It adds to the initial stimuli; changes that move the body away from homeostatic balance.
What is the job of the respiratory system?
To obtain O2 for cells and eliminate CO2 produced in the body.
What is external respiration?
The exchange of O2/CO2 between external environments and cells in the body.
What are the 4 steps of external respiration?
- Ventilation/movement of air in/out of the lungs
- O2/CO2 exchanged between air in alveoli and blood by diffusion
- blood transports O2/CO2 to lungs and tissues
- O2/CO2 exchanged between tissues and blood by diffusion
The anatomy of the respiratory system consists of:
The lungs, alveoli, diaphragm and ribs.
Where does gas exchange occur?
It takes place in the alveoli sacs
What is the conducting zone?
Where air moves through them
What is the cilia’s function in the conducting zone?
To sense temperature and air flow, it also traps foreign particles and sends them upward.
What does a feedback system consist of?
A sensory system, a relay system and response system.
What does the airway consist of?
Nose, mouth, pharynx, larynx,trachea, bronchi and bronchioles.
Why is it important to have a thin alveolar wall?
To help maximize the diffusion capabilities in gas exchange.
What is the function of type 2 alveolar cells?
To secrete pulmonary surfactant which lubricates alveoli and minimizes surface friction.
What is the function of the pores of Kohn?
To allow the movement of air between alveoli.
What is the primary muscle of inspiration?
The diaphragm
What happens when the diaphragm contracts?
It flattens and pulls the thoracic cavity down and expands.
What happens during expiration?
The inspiratory muscles relax, pressure will rise compressing the lung allowing air to move out.
What factors challenge the diaphragm?
Pregnancy, Obesity and Tumors.
Why is the pleural sac important to the lung?
It helps maintains shape, holding the chest wall and lungs in place and maintains change in pressure.
What are the 2 pleural sacs?
Visceral: attaches to the outer lung
Parietal: attaches to the thoracic wall and diaphragm
What are the 4 different pressure considerations?
Atmospheric pressure, alveolar pressure, pleural pressure and transpulmonary (recoil) pressure
Which pressure is most important for air flow in/out of lungs?
Alveolar pressure
What determines pressure?
Volume, temperature and number of molecules.
Boyle’s Law is?
P1V1=P2V2
Poiseuille’s Law is?
F= △P/R
What happens when P(pl) and P(a) are equal
The recoil pressure = 0 and theres a collapsed lung
What is lung compliance?
How much effort is required to stretch or distend the lungs.
What happens when lungs become less compliant?
The lungs stiffens up, more work is required to inflate/deflate the lung.
What determines compliance?
- Highly elastic connective tissue
- Alveolar surface tension
What is pulmonary surfactant?
A complex mixture of lipids and proteins, dispersed by water molecules in fluid lining the alveoli
What are the benefits of surfactant?
- Reduces work of lungs
- Reduces recoil pressure across different alveoli
What is law of laplace?
P=2T/R
What is the formula for air resistance?
R=△P/F
What are physical factors that influence air resistance?
- Transpulmonary pressure
- Muscus Accumulation
What neurological factors influence air resistance?
- Parasympathetic constricts radius
- epinephrine dilates
- histamine constricts
What does asthma affect?
It affects or impairs flow
What are factors of COPD?
Emphysema and chronic bronchitis
What does each disease result in?
Increased airway resistance and decreased air flow.
What do restrictive diseases do?
They reduce lung capacity
What are some examples of restrictive lung diseases?
Pulmonary Fibrosis and Neuromuscular disorders
What is tidal volume? (VT)
The volume of air in/out during a single breath
What is inspiratory reserve volume? (IRV)
The forced air passed tidal volume
What is inspiratory capacity? (IC)
The maximal volume that can be inspired
What is total lung capacity? (TLC)
The maximal volume of air lungs can hold
What is expiratory reserve volume? (ERV)
The air that is forced out during expiration
What is residual volume? (RV)
The volume of air remaining after maximal expiration
What is functional residual capacity? (FRC)
The volume of air left in lungs after a normal expiration
What is vital capacity? (VC)
The maximal air expired normally after maximal inspiration
What is FEV1?
The forced expiratory volume in 1 second
How is FVC different to VC?
FVC is forced
What does the FEV1/FVC ratio measure?
The index of flow
What is ventilation?
The amount of air moved in/out of the alveoli
What is dead space ventilation?
Gas that gets stuck in conducting airways that don’t make it to the alveoli
What is the formula for ventilation with and without dead space?
Without: VE=(VT)(f)
With: Va=(VT-VD)(f)
How do we know if alveolar ventilation is sufficient?
By looking to see if CO2/O2 levels are normal
What is the formula for alveolar ventilation?
PaCO2=(VCO2/Va)(k)
What is Dalton’s law of partial pressure?
(Pp) = Total pressure x gas fraction
What is atmospheric air comprised of?
FN2 is 0.7904 79.04%
FO2 is 0.2093 20.93%
FCO2 is 0.0003 0.03%
What is Henry’s law of gas
Cgas = Pgas x k
What is ventilation adequacy?
- hyperventilation (breathing too much)
- hypoventilation (not breathing enough)
When can inadequate gas exchange occur?
- The surface area for gas exchange is decreased
- Thickness of air and blood barrier increased
Why does hemoglobin bind O2?
It is a more efficient way to transport O2
