Respiratory System

Lecture

Processes of Respiration:

ventilation/breathing, which is the movement of air into & out of the lungs,

exchange of 02 and CO2 between the air in lungs and blood

transport of O2 and CO2 in the blood

exchange of O2 and CO2 between the blood and tissues

Functions of Respiratory System:

Regulation of blood pH

Voice production

Olfaction

Innate Immunity

Anatomy of Respiratory System has two divisions, what are the two divisions called?

upper respiratory tract (nose, pharynx, larynx)

lower respiratory tract (trachea, bronchi, lungs)

It consists of external nose (visible structure, composed mainly of hyaline cartilage) & nasal cavity (extends from nares to choanae).

Nose

external openings of nose

Nares/Nostrils

openings into the pharynx

Choanae

partition dividing nasal cavity into right and left parts

Nasal Septum

floor of nasal cavity, separating it from oral cavity

Hard Palate

body ridges on each side of nasal cavity; increase the surface area of nasal cavity & cause air to churn to be cleansed, humidified, & warmed

Conchae

air-filled spaces within bone & open into nasal cavity; resonating chambers; reduce weight of skull, produce mucus, & influence the quality of voice

Paranasal Sinuses

carry tears from eyes & open into nasal cavity

Nasolacrimal Ducts

Processes in the Nose and Nasal Cavity:

Coarse hairs inside the nares & the mucus produced by goblet cells trap large particles.

Cilia sweep the debris-laden mucus towards the pharynx, where it is swallowed.

Air is warmed by blood vessels underlying the mucous epithelium & humidified by moisture.

Sneeze Reflex:

1. Foreign substance detected by sensory receptors in superior part of nasal cavity.

2. Action potentials conducted along trigeminal nerve (V).

3. Sent to medulla oblongata.

4. Reflex is triggered.

5. Uvula & soft palate are depressed to allow the rapidly flowing air from lungs directly through nasal passages.

6. Foreign substances dislodged.

stimulated by exposure to bright light; associated with complicated wiring to pupillary reflex (pupils constrict in response to bright light)

Photic Sneeze Reflex/ACHOO (Autosomal-Dominant-Compelling-Helio-Ophthalmic-Outburst)

common passageway for both respiratory and digestive systems; divided into three regions:

Pharynx/Throat

one of the three regions of Pharynx; lined with pseudostratified ciliated columnar epithelium continuous with nasal cavity; takes in air

Nasopharynx

one of the three regions of Pharynx; lined with stratifies squamous epithelium that extends from uvula to epiglottis where oral cavity opens; takes in food, drink, & air

Oropharynx

one of the three regions of Pharynx; lined with stratified squamous & ciliated columnar epithelium which passes posterior to larynx & extends from top of epiglottis to esophagus; food & drink pass through

Laryngopharynx

located in anterior throat, extends from base of tongue to trachea; consists of 9 cartilage structures

Larynx/Voice Box

cartilage region; largest, attached to hyoid bone; opens passageway for air movement

Thyroid Cartilage/Adam’s Apple

cartilage region; most inferior cartilage that forms the base of larynx; opens passageway for air movement

Cricoid Cartilage

cartilage region; has elastic cartilage; protects airway by covering the glottis as larynx elevates during swallowing

Epiglottis

cartilage region; paired on top part; form an attachment site for vocal folds

Cuneiform Cartilage

cartilage region; paired on middle part; form an attachment site for vocal folds

Corniculate Cartilage

cartilage region; paired on bottom part; form an attachment site for vocal folds

Arytenoid Cartilage

Major Functions of Larynx:

Maintain an open airway

Protects the airway during swallowing

Produces the voice

inferior set of ligaments (true vocal cords); primary source of voice production; air moves past, causes them to vibrate & producing sounds

Vocal Folds/Vocal Cords

superior set of ligaments forms?

vestibular folds (false vocal cords)

allows air to flow into the lungs; consists of 16-20 C-shaped pieces of hyaline cartilage; projects through mediastinum & divides into the right & left primary bronchi at level of 5th thoracic vertebra

Trachea/Windpipe

Cough Reflex:

1. Foreign substances detected by sensory receptors.

2. Action potentials conducted along vagus nerve (X)

3. Sent to medulla oblongata; Reflex id triggered

4. Smooth muscle of trachea contracts (decreasing trachea’s diameter)

5. Air moves rapidly through the trachea expelling mucus & foreign substances

each connected to left & right lung & lined with cilia

Main Bronchi/Primary Bronchi

more horizontal due to displacement from heart’s location

Left Main Bronchi

wider, shorter, more vertical, more in direct line with trachea

Right Main Bronchi

principal organs in respiration; cone-shaped with its base resting on diaphragm & apex extending superiority to a point about 2.5 cm above the clavicle

Lungs

how many lobes are there in the right lung?

3 lobes

how many lobes are there in the left lung?

2 lobes

division of each lobe which separated from one another by connective tissue septa; not visible as surface fissures

Bronchopulmonary Segments

how many segments are there in the right lung?

10 segments

how many segments are there in the left lung?

9 segments

Main Bronchi > Lobar Bronchi/Secondary Bronchi (2 in left lung; 3 in right lung) > Segmental Bronchi/Tertiary Bronchi (lead to bronchopulmonary segments of lung) > Bronchioles > Terminal Bronchioles > Respiratory Bronchioles > Alveolar Ducts > Alveoli

Tracheobronchial Tree

small air-filled chambers where the air & blood come into close contact with each other; surrounded by elastic fibers that allow them to expand during inspiration & recoil during expiration

Alveoli

formed by walls of alveoli & capillaries where gas exchange takes place; consists of two layers of simple squamous, including alveolar fluid, & separating spaces

Respiratory Membrane

Layers of Respiratory Membrane:

Thin layer of alveolar fluid

Alveolar epithelium (simple squamous)

Basement membrane of alveolar epithelium

Thin interstitial space

Basement membrane of capillary endothelium

Capillary endothelium (simple squamous)

spaces around each lung; lined with a serous membrane called pleura; contains pleural fluid

Pleural Cavities

What does the pleura consist of?

Parietal Pleura (lines thoracic cavity) & Visceral Pleura (covers lung’s surface)

What are the two functions of Pleural Fluid?

>acts as lubricant, allowing the parietal & visceral pleura to slide past each other as lungs & thorax change shape during respiration

>helps hold the pleural membranes together

Process of moving air into and out of lungs; regulated by changes in thoracic volume, which produce changes in air pressure within the lungs

Ventilation/Breathing

Structure: Thoracic Cavity Volume

Inspiration/Inhalation: ?

Expiration/Exhalation: ?

Increases

Decreases

Structure: ?

Inhalation: Higher

Exhalation: Lower

Atmospheric Pressure

Structure: Alveolar Pressure

Inhalation: ?

Exhalation: Higher

Lower

Structure: Diaphragm

Inhalation: Contracts to move inferiority to expand the rib cage

Exhalation: ?

Relaxes in quiet expiration

Structure: ?

Inhalation: contracts to elevate ribs & sternum

Exhalation: Relaxes

External Intercostals

Structure: ?

Inhalation: Relaxes

Exhalation: ?

Internal Intercostals

Contracts in forceful exhalation to depress ribs & sternum

Physical Principles in Airflow into & out of Lungs:

1. Changes in volume results in changes in pressure (As the thoracic cavity volume increases, the pressure decreases)

2. Air flows from an area of higher pressure to an area of lower pressure (The greater the pressure difference, the greater the rate of airflow)

tendency for an expanded lung to decrease in size during quiet expiration; due to elastic fibers and thin film of fluid lining alveoli

Lung Recoil

What are the factors that keep the lungs from collapsing?

Surfactant

Pleural Pressure

pressure in pleural cavity; normally less that alveolar pressure to expand alveoli which is cause by fluid removal by lymphatic system & lung recoil

Pleural Pressure

mixture of lipoprotein molecules produced by secretory cells of alveolar epithelium that reduces the surface tension

Surfactant

process of measuring volumes of air that move into & out of the respiratory systems

Spirometry

the device that measures these respiratory volume (measures of the amount of air movement during different portions of ventilation)

Spirometer

respiratory volume; air inspired/expired with each breath; about 500mL at rest

Tidal Volume

respiratory volume; air inspired forcefully; about 3L

Inspiratory Reserve Volume

respiratory volume; air expired forcefully; about 1L

Expiratory Reserve Volume

respiratory volume; remaining air after maximum expiration; about 1.2L

Residual Volume

sums of two or more respiratory volumes; total volume of air contained ranged from 4 to 6 L

Respiratory Capacities

expiratory reserve volume + residual volume

Functional Residual Capacity

Inspiratory Capacity

tidal volume + inspiratory reserve volume

tidal volume + inspiratory & expiratory reserve volume

Vital Capacity

Total Lung Capacity

tidal + residual + inspiratory reserve + expiratory reserve volume

rate at which lung volume changes during direct measurement of vital capacity

Forced Expiratory Vital Capacity

The site of respiration inside the lungs are?

Alveoli

What is the function of trachea?

Carries air to lungs

Which of the followingi