Anaphy (RESPIRATORY)

respiratory

Gas exchanges between the blood and external environment occur only in

1. alveoli of the lungs 

**Upper respiratory tract**

1. passageways from the __nose to larynx__

nose:

__only structure that is externally visible__

**Lower respiratory tract**

1. passageways from __trachea to alveoli__

**Conducting zone**

air Pathways but not directly related to exchange of gasses (trachea to bronchioles)

Lining of the respiratory system is covered by

__mucosa__

__mucosa__

for humidity, warm, purify: retains moisture and has enzymes that ensures filtering and destroying harmful substances

**Cilia**:

* filtering the unnecessary materials in the air

**coughing**

* dislodge the materials in the lower respiratory tract

**sneezing**

non respiratory movement to dislodge the materials in the upper respiratory tract

**EXTERNAL RESPIRATION**

alveoli and blood exchange

Internal respiration

blood and tissue cells exchange

**Respiratory Zone**

structures directly connected and participates in the __*actual exchange of gas (respiratory bronchioles)*__

Oral cavity

accessory organ; if clogged nostrils it facilitates the entry of gases

Pharynx

throat; common passage- way for food and air

Lymphatic vessels form by

budding

Larynx

anterior of esophagus (voicebox); hyaline

Trachea

windpipe; Divided to L and r primary bronchi

Carina

junction at the middle portion of trachea

Fissures

* responsible for lobation of the lungs

**Nostrils (nares)**

route wherein air enters the nose

**Nasal cavity**

 interior of the nose

**Nasal** **septum**

divides the nasal cavity; produce mucus

**Olfactory receptors**

* __mucosa on the superior surface__

respiratory mucosa

rest of the cavity is lined with

**Conchae**

* __projections from the lateral wall; increase surface area, turbulence__

**palate**

* __separates the nasal cavity from the oral cavity__

**Hard palate**

*anterior separation of mouth and nose and supported by bone*

**Soft palate**

*posterior separation of mouth and nose and unsupported by bone*

**Paranasal sinuses**

* Cavities within the frontal, sphenoid, ethmoid, and maxillary bones surrounding the nasal cavity

Sinuses:

* __Lighten the skull__
* __Act as resonance chambers for speech__
* __Produce mucus__

**Uvula**

dangling piece of tissue

* Gagging reflex
* One way food inside

Three regions of the pharynx

**Nasopharynx; Oropharynx; Laryngopharynx**

The pharynx

Muscular passageway from nasal cavity to larynx

**Nasopharynx**

*  __superior region of pharynx__ *behind nasal cavity*

**Oropharynx**

__middle region__ *behind mouth*; entry point of both air and food 

**Laryngopharynx**

__inferior region__ *attached to larynx*

**Epiglottis**

* __routes food into the posterior tube__, the esophagus

**Pharyngotympanic tubes**

* open into the nasopharynx
* __drain the middle ear__

**Tonsils**

clusters of __*lymphatic tissue*__

**Pharyngeal tonsil (adenoid)**

*  __a single tonsil__, is *located in the nasopharynx*

**Palatine tonsils (2)**

*in the oropharynx at the end of the soft palate*

**Lingual tonsils (2)**

*found at the base of the tongue*

**The Larynx**

voice box, __routes air and food into the proper channels__ and plays a role in speech.

This larynx

* inferior to the pharynx
* *eight rigid hyaline cartilages*
* **Thyroid cartilage (Adam’s apple)** is the largest

**Epiglottis**

* *Spoon-shaped flap of elastic cartilage*
* Protects the superior opening of the larynx

**Vocal folds (true vocal cords**)

* Vibrate with expelled air
* Allow us to speak


* The glottis includes the vocal cords and the opening between the vocal cords

**The Trachea**

* __*4-inch-long*__ tube that *connects to the larynx*
* reinforced with __*C-shaped rings*__ of hyaline cartilage
* **the windpipe**

Cilia beat

* continuously in the __opposite direction of incoming air__

**Main Bronchi**

* Formed by division of the trachea
* Bronchi subdivide into smaller and smaller branches

**hilum**

Each bronchus enters the lung at the **hilum** (medial depression of lungs)

__*Right bronchus*__

__*wider, shorter, and straighter than left*__

**Lungs**

* Occupy the entire thoracic cavity except for the central mediastinum (occupied by the heart) 
* apex=clavicle
* base = near diaphragm

**left lung**

 two lobes

**right lung**

three lobes

**Serosa**

covers the outer surface of the lungs

Pulmonary (visceral) pleura

covers the lung surface

Parietal pleura

 lines the walls of the thoracic cavity

**Pleural fluid**

* fills the area between layers
* Allows the lungs to glide over the thorax
* Decreases friction during breathing

**Pleural space**

* (between the layers) is more of a potential space

**The bronchial tree**

* Main bronchi subdivide into smaller and smaller branches
* __network of branching passageways__

**Bronchioles**

*smallest conducting passageways*

**Respiratory Zone**

* Respiratory bronchioles
* Alveolar ducts
* Alveolar sacs
* **Alveoli** (air sacs)—__the only site of gas exchange__

**Alveoli**

__Simple squamous epithelial cells__ largely composed the walls

*Alveolar pores*

* __connect neighboring air sacs__

Pulmonary capillaries

* cover external surfaces of alveoli

**Respiratory membrane**

* **(air-blood barrier)**
* On __one side of the membrane is air__, and __on the other side is blood__ flowing past
* diffusion

Formed by *alveolar and capillary walls*

Partial pressure diffusion of gases

* __move from an area of High partial pressure to low partial pressure__.

**Alveolar macrophages**

“dust cells” __Add protection__ by picking up bacteria, carbon particles, and other debris

**Surfactant**

 **lipid molecule;** __Coats gas-exposed alveolar surfaces__

* Functions of the respiratory system

* __Supply the body with oxygen__
* __Dispose of carbon dioxide__

**Pulmonary ventilation**

1. __moving air into and out of the lungs__ (commonly called **breathing**)

*Respiratory gas transport*

1. __transport of oxygen and carbon dioxide__ via the **bloodstream**

__four distinct events__

* Pulmonary ventilation
* External respiration
* Respiratory gas transport
* Internal respiration

**Pulmonary ventilation**

* __depends on volume changes in the thoracic cavity__
* __pressure changes__, which lead to the __flow of gases to equalize pressure__

**Two phases of pulmonary ventilation**

* __*Inspiration*__ = inhalation
* Flow of air into lungs
* __*Expiration*__ = exhalation
* Air leaving lungs

**Inspiration (inhalation**)

* __Diaphragm and external intercostal muscles contract__
* **Intrapulmonary volume increases**
* **Gas pressure decreases**
* Air flows into the lungs until intrapulmonary pressure equals atmospheric pressure

**Expiration (exhalation)**

* passive process that depends on natural lung elasticity
* __Gas pressure__ __*increases*__ (*greater interaction between air molecules*)

__Intrapulmonary volume__

*actual space inside the lungs*

__*Normal breathing*__

500 ml

**Forced expiration**

* contraction of **internal** intercostal muscles to depress the rib cage

**Inspiration**

Intrapulmonary volume __*increases*__, pressure __*decreases*__

**Expiration**

Intrapulmonary volume __*decreases*__, pressure __*increases*__

**Intrapleural pressure**

* pressure within the pleural space -negative

If intrapleural pressure equals atmospheric pressure

* the lungs recoil and collapse (should be avoided)

Volume of breath

* at peak in between inspiration and expiration

**Factors affecting respiratory capacity**

* size
* sex
* age
* physical capacity

**Tidal volume (TV)**

* Normal quiet breathing
* __***500 ml of air***__ is moved in/out of lungs with each breath

**Inspiratory reserve volume (IRV)**

* Amount of air that can be taken in forcibly over the tidal volume
* Usually around __***3,100 ml***__

**Expiratory reserve volume (ERV)**

* amount of air that can be forcibly exhaled after a tidal expiration

Approximately __**1,200 ml**__

**Residual volume**

* Air *remaining in lung* after expiration
* Cannot be voluntarily exhaled 
* Allows gas exchange to go on continuously, even between breaths, and *helps keep alveoli open (inflated)*
* About __**1,200 ml**__

**Vital capacity**

* total amount of exchangeable air
* TV + IRV + ERV

Vital capacity of men

__**4,800**__

Vital capacity of women

__**3,100 ml**__

**Dead space volume**

* Air that remains in conducting zone and *never reaches alveoli*

About __**150 ml**__

**Functional volume**

* Air that actually reaches the respiratory zone

Usually about __**350 ml**__

__**spirometer**__

**Respiratory capacities are measured with**

**Cough and sneeze**

* clears lungs of debris

**Crying**

emotionally induced mechanism; increases respiratory rates

**Laughing**

similar to crying