what does the respiratory system consist of?

nose

pharynx

larynx

trachea

bronchi

lungs

what is the volume of anatomic dead space?

150ml

what are alveoli?

what is it function?

small, thin walled sacs that have capillary beds in their walls

site of gas exchange between air and blood

what is respiratory membrane?

lungs?

alveolar - capilary membranes that seperate the air molecules in the alveoli from the blood in the capillaries.

has a very surface area - 70sq -- size of a tennis court

L: conducting airways, alveoli, blood vessels and elastic tissue

what is fick's law of diffusion?

what is boyles law?

the pressure of gas is inversely proportional to its volume

P1V1 = P2V2

explain the mechanics of breathing

• molecures move from areas of high pressure or concentration to area of low pressure / concentration.

• movement of air in and out of the lungs = pressure differences b/w the pulmonry air and the atmostphere

what is inspiration?

active process; where the idaphram descends and external intercostal muscles contract thus increasing the volume of the thorcic cavity.

  air molecules move through the respiratory tubes into the lungs from the atmosphere following the pressure gradient

they work @ the hardest when they produce a negative presure as great as -30mmHg below atmostphereic pressure in the alveoli

what is expiration?

passive process at rest; secondary muscles like abdominal muscles become involved in exercise

what happens during forced expiration?

produces intra-alveolar pressure as great as 50 mmhg above atmostpheric pressure

what happens during exercise / respiration

mouth breathing tends to replace nasal breathing -- less resistance to airflow

air enters the respiratory passage via the nose or mouth which is quickly saturated with water vapor adn warmed to body temp

what is compliance?

it is the amount of volume change in the lung for a given change in alveolar pressure

@ rest. normal values are?

minute ventilation

tidal volume

breathing frequency

expiratory reserve volume

inspiratory capacity

total lung capcity

VE - 6-8 L/min

VT - 500ml/ insiration and expiration

ERV - aprox 25% of vital capacity

FR - 12 -16breaths/ minute

IC - aprox 75% of VC

TLC- vital capacity plus reidual volume - theres always iar left in the lung

what is alveolar ventilation?

volume of air that reaches that alveoli per minute. this value is very important because this is the only air that participates in gas exchange. with blood.

what are the 2 reasons for most volumes and capacities decrease when a person lies down and increases when standing?

1. abdominal contents push up and against the diaphram

2. there is an increase in a trapulmonary bood volume in the horizontal position that decrease the space available for pumonary air.

what are pulmonary function test normal usually based on?

sex, age, and height.

what are the two things important to know about the population used to construct the norm?

pop size and make up

what are the problems with pulmonary function norms?

1. consider the "size" of the subject -- chest size

2.be better to use sitting height rather than standing height

what are the two chronic pulmonary dysfunctions that can be divided into?

1. obstructive disorders

2. restrictive disorders

explain obstructive disorders

blockage or narrowing of the aircause that cause increased airway resistance --- asthma, bronchitis, emphysema

-- result of inflammation and edema, smooth muscle constriction, bronchiolar secretion

air is difficult to move air rapidly in and out of lungs.

explain restrictive disorders

- no problem with the airway, but theres damage to the lung tissue.

loss of elasticity and compliance -- limited exansion of the lungs, pulmonary fibrosis, pneumonia

all lung volumes are reduced because lung tissue is stiff and cant expan really far.

pulmonary function test must be interpreted in relation to what?

patients medical history, occupational history, smoking habits and chest X rays

what is ventilatory threshold?

the point at whichminute ventilation incresae disproportionatel with O2 consumption during graded exercise

what happens during exercise in relations to minute ventilation ?

minute ventilation increase linearly with increasing exercise intensity and o2 uptake until approx 60% of Vo2 max --

in untrained subjects and 75-80 % of Vo2 max in endurance athletes