Breathing, which involves the physical movement of air into and out of the lungs is

pulmonary ventilation(respiratory system)

transport of oxygen and carbon dioxide between lungs and tissue
(circulatory system)

transport

exchange of O2 and CO2 between the lungs and the blood(respiratory system)

External respiration (respiratory system)

O2 and CO2 exchange between systemic blood vessels and tissues

Internal respiration(circulatory system)

Four processes that supply the body with O2 and dispose of CO2

pulmonary ventilation, External respiration, transport, Internal respiration

site of gas exchange

Respiratory zone

conduits to gas exchange sites

Conducting zone

diaphragm and other muscles that promote ventilation ( expand volume of chest cavity)

Respiratory muscles

microscopic structure of respiratory zone

respiratory bronchioles, alveolar ducts, and alveoli

account for most of the lungs’ volume and are the main site for gas exchange

alveoli

how many alveoli do we have

approximately 300 milion

the thickness of air-blood barrier in respiratory membrane

~ 0.5 micrometer

the Single layer of squamous epithelium

alveolar wall

the simple squamous lining the alveoli is called

type 1 cells

type 2 cell secrete

surfactant

alveoil is Surrounded by and contain

fine elastic fibers, open pore

open pores that Connect adjacent alveoli

–Allow air pressure throughout the lung to be equalized

_____ House alveolar macrophages that keep alveolar surfaces sterile

Alveoli

lung that is smaller, has two lobes and an oblique fissure

left lung

right lung has

is larger has three lobes separated by oblique and horizontal fissures

blood supply

there are two circulations:
1. pulmonary (low pressure, high volume)
2.bronchial ( high pressure, low volume) provides these tissues with oxygen and nutrients

thin double layered serosa, produce pleural fluid

pleurae

Parietal pleura cover

thoracic wall and superior face of diaphragm

pleura on external lung surface

visceral

function of the pleural fluid

fills the slitlike pleural cavity and Provides lubrication and surface tension

Pulmonary ventilation consists of how many phase

2, inspiration and expiration

gases flow into the lungs

inspiration

expiration

gases exit the lungs and has positve pressure

Pressure exerted by the air surrounding the body

Atmospheric pressure (Patm)

Atmospheric pressure (Patm) is _____ at sea level

760 mm Hg or 1 atm

is the pressure within the aveoli, its always very close to the (Patm)
It fluctuates with breathing but equalizes quickly with the (Patm)

Intrapulmonary (intra-alveolar) pressure (Ppul)

Negative respiratory pressure is less than or greater than Patm or equal to Patm

less than

positive respiratory pressure is less than or greater than Patm or equal to

greater than Patm

zero respiratory pressure is less than or greater than Patm or equal to Patm

equal to Patm

is the pressure within the pleural cavity between lungs and thoraciv wall. This pressure is always slightly less than the (Ppul) and atmospheric pressure and always a negative pressure

Intrapleural pressure (Pip)

Negative Pip is caused by

opposing forces

___force promote lung collapse and ____ force tends to enlarge the lungs

inwards force, outward force

Two inward forces promote lung collapse in intrapleural pressure

• Elastic recoil of lungs decreases lung size
• Surface tension of alveolar fluid reduces alveolar size

Elasticity of the chest wall pulls the

thorax outward

if intrapleural pressure is equal to intrapulmonary pressure Pip = Ppul, what happens to the lungs?

lose the negative pressure and the lungs collapse

transpulmonary pressure calculation

760 mm Hg - 756 mm Hg = 4 mm Hg

Intrapleural pressure

756 mm Hg
(- 4 mm Hg)

Intrapulmonary pressure

760 mm Hg
(0 mm Hg)

transpulmonary pressure

intrapulmonary pressure minus intrapleural pressure.

function of transpulmonary pressure

keeps the airways open (keeps the lungs from collapsing)

The greater the transpulmonary pressure, the larger or smaller the lungs

larger

Atelectasis

collapse of lung tissue

Atelectasis (lung collapse) is due to

–Plugged bronchioles ---- collapse of alveoli

–Wound that admits air into pleural cavity (pneumothorax)

Mechanical processes that depend on volume changes in the thoracic cavity

Pulmonary Ventilation

Pulmonary Ventilation

Volume changes lead to pressure changes and in turn flow of gas to quickly equalize pressure

Pulmonary ventilation
- volume changes leads to what

pressure changes

inspiration is an active or passive process

active

what happens to the inspiratory muscles during inspiration

contract

does the thoracic volume increase or decrease during inspiration?

increase

what happens to the lungs and intrapulmonary volume during inspiration?

lungs stretch
intrapulmonary VOLUME increases

what happens to the intrapulmonary pressure during inspiration and expiration?

inspiration-it drops to -1 mm Hg

expiration- Ppul rises (to +1 mm Hg)

what happens to air during inspiration and expiration?

during inspiration air flows into the lungs, down its pressure gradient, until Ppul = Patm while in expiration Air flows out of the lungs down its pressure gradient until Ppul = 0

is forced expiration passive or active

active

what happens to the inspiratory muscles during expiration

they relax

what happens to the thoracic volume during expiration

decrease

what happens to the lungs and intrapulmonary volume during expiration

lungs recoil
intrapulmonary volume decreases

what happens to the intrapulmonary pressure as lung volume increases during inspiration?

pressure inside the lung decreases

during each breath, the pressure gradient moves how many liters/ml of air into and out of the lungs?

500 ml or 0.5 liters

Inspiratory muscles consume energy to overcome 3 physical factors that hinder air passage and pulmonary ventilation

1. airway resistance
   2. alveolar surface tension
   3. lung compliance

As airway resistance rises, breathing movements become more

strenuous

What effect does severely constricting or obstruction of bronchioles have?

–Can prevent life-sustaining ventilation

–Can occur during acute asthma attacks and stop ventilation

can dilates bronchioles and reduces air resistance

Epinephrine

alveolar surface tension

–Attracts liquid molecules to one another at a gas-liquid interface

–Resists any force that tends to increase the surface area of the liquid

Detergent-like lipid and protein complex and can Reduces surface tension of alveolar fluid and discourages alveolar collapse

Surfactant

what is lung compliance

A measure of the change in lung volume that occurs with a given change in transpulmonary pressure

lung compliance is diminished by 3 things:

1.non-elastic scar tissue (fibrosis)
2. reduced production of surfactant
3. decreased flexibility of the thoracic cage

Dalton's Law of Partial Pressures

total pressure= PP of a gas A+PP of gas B
the partial pressure of each gas is directly proportional to its percentage in the mixture

Basic Properties of Gases

air is a mixture of gases carbon dioxide, oxygen and nitrogen

Henry's Law

when a mixture of gas is in a liquid (plasma) each gas will dissolve in the liquid in proportion to is partial pressure

The amount of gas that will dissolve in a liquid also depends upon its

solubilty

CO2 is ___times more soluble in water than O2

20 X

External Respiration

Exchange of O2 and CO2 across the respiratory membrane

Factors influencing external respiration

–Partial pressure gradients and gas solubilities

–Ventilation-perfusion coupling

–Structural characteristics of the respiratory membrane

does CO2 diffuses in equal amounts or greater amount or lesser amount with oxygen

equal amount

________amount of gas reaching the alveoli

ventilation

respiratory membrane

–0.5 to 1 mm thick

–Large total surface area (40 times that of one’s skin)

the respiratory membaene become what if lungs become waterlogged and edematous, and gas exchange becomes inadequate

thicken

Loading and unloading of O2 is facilitated by

change in shape of Hb

As O2 binds, Hb affinity for O2______ while As O2 is released, Hb affinity for O2 ______

increase, decease

oxygen is fully saturated when

all four heme groups carry O2

oxygen is Partially saturated when

one to three hemes carry O2

Rate of loading and unloading of O2 is regulated by

–Po2, Temperature, Blood pH, Pco2

percentage of bound O2 is unloaded during one systemic circulation

20-25%

Increases in temperature, H+, Pco2, and BPG

–Modify the structure of hemoglobin and decrease its affinity for O2

As cells metabolize glucose, Pco2 and H+

increase in concentration in capillary blood

• CO2 is transported in the blood in how many forms

three

–7 to 10% dissolved in plasma

–20% bound to globin of hemoglobin (carbaminohemoglobin)

–70% transported as bicarbonate ions (HCO3–) in plasma

HCO3–

bicarbonate ions

Control of Respiration involve

neurons in the reticular formation of the medulla and pons

Medullary Respiratory Centers

Dorsal respiratory group (DRG) and Ventral respiratory group (VRG)

Sets eupnea is

12–15 breaths/minute

Depth and Rate of Breathing are modified

in response to changing body demands

____ are the most powerful respiratory stimulant

Rising CO2 levels

_______ is increased depth and rate of breathing that makes the body remove too much CO2

Hyperventilation

what is an apnea

period of breathing cessation that occurs when Pco2 is abnormally low

what is Hyperpnea

Increase in ventilation (10 to 20 fold) in response to metabolic needs

COPD

Chronic obstructive pulmonary disease

irreversible decrease in the abilty of COPD

force air out of the lungs

COPD is exemplified by

chronic bronchitis and emphysema

common features of COPD

• History of smoking in 80% of patients
• Dyspnea: labored breathing (“air hunger”)
• Coughing and frequent pulmonary infections
• Most victims develop respiratory failure (hypoventilation) accompanied by respiratory acidosis

homeostatic imbalance that is Characterized by coughing, dyspnea, wheezing, and chest tightness. it is also an Active inflammation of the airways precedes bronchospasms

Asthma

Lung cancer

–Leading cause of cancer deaths in North America

–90% of all cases are the result of smoking

the three most common type of lung cancer

Squamous cell carcinoma, Adenocarcinoma, and Small cell carcinoma