Ch 22 respiratory system

Gas exchange

Supplies body with O2 and removes CO2

Processes of Respiration

Pulmonary ventilation

External Respiration

Transport of Respiratory of Gases

Internal Respiration

.  Pulmonary ventilation (breathing)

inspiration and expiration, movement of  

        air into and out of lungs-exchange of air b/w atmosphere and alveoli of

        lungs.

and expiration, movement of
air i

.  External Respiration

lungs (pulmonary capillaries)

  Oxygen moves from the lungs into blood

  Carbon dioxide moves from the blood into the lungs

Transport of respiratory gases

Transport of oxygen from the lungs to the tissue cells

  Transport of carbon dioxide from the tissue cells to the lungs

.  Internal Respiration-

body tissues- (systemic capillaries)

  Oxygen moves from the blood to the body cells

  Carbon dioxide moves from the body cells into the blood

larynx up

Upper respiratory system-

larynx down

Lower respiratory system

Functions of external nose:

1.  provides an airway for respiration

  2.  warms, moistens, and filters incoming air

  3.  detects olfactory stimuli

  4.  speech chamber- modifies vibrations as they

       pass through the resonating chambers

Two types of mucous membranes in nasal cavity

Respiratory mucosa

Olfactory mucosa

Respiratory mucosa

Nasal     

        Mucosa

  – pseudostratified ciliated columnar epithelium w/      large amounts of globlet cells

Olfactory mucosa

Olfactory epithelium

  - olfactory receptors for smell

What are the 3 regions of pharynx

3 Regions:

         Nasopharynx

         Oropharynx

         Laryngopharynx

 

Lined with Pseudostratified ciliated columnar epithelium

Nasopharynx

rises up to close of 

     nasopharynx and prevent food

     from entering

Uvula-

nasopharynx contains

adenoids (pharyngeal tonsils)

  -tubal tonsils

what are the 5 opening

-5 openings: 

       2 internal nares

       2 openings to the auditory tube                   

       1 opening  into oropharynx

Lined with stratified squamous

 epithelium

Oropharynx

respiratory and digestive function

food, drink and air passage

-contains tonsils

-palatine tonsils

lingual tonsils

Oropharynx

Lined with stratified squamous

 epithelium

Laryngopharynx

respiratory and digestive function

air and food passage

Description of the Larynx

Short passageway connecting laryngopharynx with trachea

air passage, switching mechanism to route food and air into the

     proper channels, and voice production.

Cilia in upper respiratory tract move mucous and trapped particles down toward pharynx

Cilia in lower respiratory tract move them up toward pharynx

prevents food from entering the trachea

Epiglottis

sound

pitch

speech:

Trachea

Posterior Tracheal Wall

Conducting Zone Structures

Trachea-(primary) bronchi-(secondary bronchi)-(tertiary Bronchi)- bronchioles-Terminal bronchioles-respiratory bronchioles-alveolar ducks

     - last bronchiole before 

       alveoli

Terminal bronchiole

- exhibit  alveoli

-wall consists entirely of

       alveoli

Respiratory bronchioles

- terminate in sacs of alveoli

Alveolar duct

     - consist of two or more

       alveoli

=

Alveolar sac

– structure in lung where gas

        exchange takes place

Alveoli

Respiratory Zone

Respiratory bronchioles-alveolar ducts (lead into alveolar sacs)

Overall Histological changes as respiratory passages branch:

1.  loss of cartilage

2.  proportional amount of smooth muscle increases (though it is absent in alveoli)

3.  gradual thinning of epithelium

1° bronchi àtertiary bronchi-  psuedostratified ciliated columnar epithelium

      bronchioles - simple columnar epithelium (w/ globlet cells)

       terminal bronchioles - simple cuboidal

      ducts + sacs- simple squamous - smooth muscle

          alveoli - very elastic - have elastic fibers

What are the three types of Aveolar

-Type I alveolar cells

macrophages

-Type II alveolar cells

-- form alveoli – site of gas 

    exchange

-Type I alveolar cells

("dust cells") remove  

   dirt and debris from alveolar space

macrophages

-secretes surfactant  - prevents 

          alveolar  collapse upon recoil

   -secrete alveolar fluids-keeps air

  moist

  -secretes antimicrobial proteins

-Type II alveolar cells

-the barrier that respiratory gases must pass during external respiration

*Membrane made up of alveolar wall and capillary wall

The Respiratory Membrane (alveolar capillary membrane):

Paired organs in thoracic cavity

    -Fissure divide the lungs into lobes

  - Right lung 3 lobes

  - Left lung 2 lobes 

   

-Left lung about 10% smaller

  than right lung

=

Lungs

Each lung enclosed by double-layered pleural membrane

Parietal pleura

Visceral pleura

most superficial           

               lines wall of thoracic cavity

Parietal pleura

covers lungs themselves

Visceral pleura

space between layers

Pleural cavity

reduces friction, produces surface tension

Pleural fluid

inflammation of pleural  membrane-     

              causes pain due to friction between layers- if it 

              persists, excess fluid is produced and accumulates

              in pleural space -pleural effusion

Pleurisy=pleuritis-

- lung collapse usually just part of lung;

             rarely entire lung

Atelectosis

-is 760mmHg at sea level

external air pressure

atmospheric pressure (P_atm)

(during quiet inhalation pressure

    inside alveoli decreases to 758mmHg

-air pressure in alveoli

- Alveolar pressure (P_alv)=

(always about 4 mmHg less

     than alveolar pressure- this must be

     maintained to prevent collapse of lungs

pressure exerted by pleural

     fluid in pleural cavities

intrapleural pressure (P_ip)

n  involves changing volume of thoracic cavity to produce  

       pressure gradients (drives air into or out of lungs)

Pulmonary Ventilation

describes the relationship between the pressure and     

          volume of a gas.

Boyles law

In the lungs- when the lungs expand, lung volume  increases, 

         and pressure inside the lungs falls below atmospheric  pressure

         and air moves into the lungs. what happens to the diaphragm

diaphragm contrast ( lungs inhale)

In the lungs- when lung volume decreases (expiration), pressure

         inside the lungs is greater than the atmospheric pressure

         (pressure increases) and air moves out of the lungs. What happens to the diaphragm

diaphragm relaxes lungs exhale

nInvolves muscle contraction.

  *air moves into lungs when the air pressure inside    the lungs is less than the air pressure in the 

            atmosphere.

Inspiration is active

– most important muscle of inhalation

Flattens, lowering dome when contracts, this increase in volume decreases the pressure inside the lungs below atmospheric pressure and allows air to enter

Responsible for 75% of air entering lungs during normal quiet breathing

Diaphragm

Contraction elevates ribs

this increases the volume by increasing the diameter of the thoracic cavity

25% of air entering lungs during normal quiet breathing

External intercostals

Accessory muscles for deep, forceful inhalation

sternocleidomastoid, pectoralis minor,and scalenes

Normally passive – muscle relax instead of contract 

due to elastic recoil of lungs and chest wall

Exhalation

Forced expiration (active) involves contraction of abdominal muscles and internal intercostals -occurs during exercise and playing wind instruments.

Forced Expiration

What are the 3 nfactors affect rate of airflow and ease of pulmonary ventilation

Alveolar Surface Tension

Lung compliance

Airway resistance

Alveolar Surface Tension

Lung compliance

.  Airway resistance

Ventilation can be measured using a

spirometer