HBIOANA Respiratory System (c/o Zab)

- Provide oxygen to body tissues for cellular respiration
- Remove the waste product carbon dioxide
- Used for non-vital functions, such as sensing odors,
speech production, and for straining
- Help maintain acid-base balance

Functions of the Respiratory System

Acidosis & alkalosis

may occur if acid-base in the body is not balanced

conducting zone

- includes the organs and structures, not directly involved in gas exchange
- Provide a route for incoming and outgoing air
- Remove debris and pathogens from the incoming air.
- Warm and humidify the incoming air

respiratory zone

- Where gas exchange occurs
- Includes structures that are directly involved in gas exchange.
- Begins where the terminal bronchioles join a respiratory bronchiole, which then leads to an alveolar duct, opening into a cluster of alveoli

Epithelium of the nasal passages

essential to sensing odors

Bronchial epithelium

lines the lungs can metabolize some airborne carcinogens

External Nose

surface and skeletal structures that result in the outward appearance of the nose

root

region of the nose located between the eyebrows

bridge

connects the root to the rest of the nose

dorsum nasi

length of the nose

apex

tip of the nose

ala

cartilaginous structure that forms the lateral side of each naris

Naris

nostril opening

philtrum

concave surface that connects the apex of
the nose to the upper lip

root and bridge

The \_________ & \_________ of the nose consists of bones

Cartilage

The protruding portion of the nose in made up of \_________

nasal bone

- One pair of bones
that lies under the root and bridges the nose.
- Articulates superiorly with the frontal bone and laterally with the maxillary bones

Septal cartilage

Flexible hyaline cartilage connected to the nasal bone, forming the dorsum nasi

alar cartilage

The apex of the nose surrounding the naris

nares

Open into the nasal cavity, which is separated into left and right sections by the nasal septum

nasal septum

Formed anteriorly by a portion of the septal cartilage (flexible portion) and posteriorly by the perpendicular plate of the ethmoid bone and the thin vomer bones

superior, middle and inferior conchae

Serve to increase the surface area of the nasal cavity and to disrupt the flow of air as it enters the nose causing air to bounce along the epithelium, where it is cleaned and warmed

conchae and meatuses

conserve water and prevent dehydration of the nasal epithelium by trapping water during exhalation

hard palate

At anterior region of the nasal cavity is composed of bone

soft palate

At the posterior portion of the nasal cavity consists of muscle tissue

Paranasal Sinuses

- Serve to warm and humidify incoming air.
- Lined with mucosa.
- Named for its associated
bone
- Produce mucus and lighten the weight of the skull

- Frontal sinus
- Maxillary sinus
- Sphenoidal sinus
- Ethmoidal sinus

All types of sinuses

Mucosa of the nares and anterior nasal cavities

- Mucous membranes containing sebaceous glands and hair follicles.
- Prevent the passage of large debris, such as dirt, through the nasal cavity.
- Capillaries located beneath the nasal epithelium warm the air by convection

olfactory epithelium

Used to detect odors found deeper in the nasal cavity

conchae, meatuses, and paranasal sinuses

Lined by respiratory epithelium composed of
pseudostratified ciliated columnar epithelium.

Goblet cells

produce mucus to trap debris

Cilia

help remove the mucus and debris from the
nasal cavity with a constant sweeping motion towards the throat to be swallowed

Pharynx

- A tube formed by skeletal muscle.
- Lined by mucous membrane that is continuous with that of the nasal cavities.
- Divided into the nasopharynx, the oropharynx, and the laryngopharynx.

Nasopharynx

- Flanked by the conchae of the nasal cavity.
- Serves only as an airway.

Pharyngeal tonsil (an adenoid)

- An aggregate of lymphoid reticular tissue similar to a lymph node that lies at the superior portion of the nasopharynx.
- Contains a rich supply of lymphocytes and is covered with ciliated epithelium that destroys invading pathogens that enter during inhalation.
- Large in children, but tend to regress with age and may even disappear

Uvula

- Small teardrop-shaped structure located at the apex of the soft palate
- Prevent ingested material from entering the nasal cavity

Auditory (Eustachian) tubes

Connect each middle ear cavity to the nasopharynx

Oropharynx

- A passageway for both air and food.
- Bordered superiorly by the nasopharynx and anteriorly by the oral cavity.
- The epithelium changes from pseudostratified ciliated columnar epithelium to stratified squamous epithelium.
- Contains the palatine and lingual tonsils

palatine and lingual tonsils

Composed of lymphoid tissue that trap and destroy pathogens entering through the oral or nasal cavities

Palatine tonsil

pair of structures located laterally in the
oropharynx

Lingual tonsil

Located at the base of the tongue

Larungopharynx

- Inferior to the oropharynx and posterior to the larynx.
- Continues the route for ingested material and air until
where the digestive and respiratory systems diverge.
- The stratified squamous epithelium of the oropharynx is continuous with the laryngopharynx.
- Anteriorly, the laryngopharynx opens into the larynx.
- Posteriorly, it enters the esophagus

Larynx

- A cartilaginous structure that connects the pharynx to the trachea.
- Helps regulate the volume of air that enters and leaves the lungs.
- Formed by several pieces of cartilage.

Thyroid cartilage

- The largest piece of cartilage that makes up
the larynx
- Where the Adam's Apple can be found

Laryngeal Prominence

Adam's Apple

Cricoid cartilage

Forms a ring, with a wide posterior region and a
thinner anterior region

Arytenoids, corniculates, and cuneiforms

Paired cartilages attached to the epiglottis and the vocal cords and muscle that help move the vocal cords

epiglottis

- Attached to the thyroid cartilage.
- A very flexible piece of elastic cartilage that covers the opening of the
trachea

glottis

Composed of thevestibular folds, the true vocal cords, and the space between these folds

vestibular fold or false vocal cord

One pair of folded sections of mucous membrane

true vocal cord

- Membranous folds attached by muscle to the thyroid and arytenoid cartilages of the larynx
- Folds in males tend to be larger, which create a deeper voice

act of swallowing

- Causes the pharynx and larynx to lift upward,
allowing the epiglottis to swing downward, closing the opening to the trachea.
- Preventing food and beverages from entering the trachea

Mucosal lining

- The superior portion of the larynx is lined with stratified squamous epithelium, transitioning into pseudostratified ciliated columnar epithelium that contains goblet cells.
- Produces mucus to trap debris and pathogens as they enter the trachea

Tranchea

- Extends from the larynx toward the lungs.
- Lined by pseudostratified ciliated columnar epithelium.
- Formed by 16-20 C-shaped hyaline cartilage that are connected by dense connective tissue.

fibroelastic membrane

- Formed by trachealis muscle and elastic connective tissue, which closes the posterior
surface of the trachea.
- Allows trachea to stretch inhalation and exhalation

tracheal rings

Provide structural support and prevent the trachea from collapsing

Bronchial Tree

- The collective term used for these multiple-branched bronchi.
- Provide a passageway for air to move into and out of each lung.
- The mucous membrane traps debris and pathogens
- The trachea branches into the right and left primary bronchi at the carina

Bronchi

- Lined by pseudostratified ciliated columnar epithelium containing mucus-producing goblet cells
- Rings of cartilage support the structure and prevent collapse

carina

Contains nervous tissue that induces violent coughing if a foreign body is present

primary bronchi

Enter the lungs at the hilum, a concave region where blood vessels, lymphatic vessels, and nerves also enter the lungs

Bronchioles

- Branch out from the tertiary bronchi.○ About 1 mm in diameter.
- Continues to branch until they become the tiny
terminal bronchioles.
- Muscular walls of the bronchioles do not contain cartilage like those of the bronchi, instead, it can change the size of the tubing to increase or decrease airflow through the tube

Terminal bronchioles

Lead to the structures of gas exchange

alveolar duct

A tube composed of smooth muscle and connective tissue, which opens into a cluster of alveoli

alveolus

- One of the many small, grape-like sacs that are attached to the alveolar ducts.
- ~200 μm in diameter with elastic walls that allow the alveolus to stretch during air intake.
- Connected to their neighbors by alveolar pores

Type I alveolar cell

- A squamous epithelial cell of the alveoli.
- Constitute up to 97% of the alveolar surface area.
- About 25 nm thick and highly permeable to gases

Type II alveolar cell

- Interspersed among the type I cells.
- Secretes pulmonary surfactants.
- Composed of phospholipids and proteins that
reduce the surface tension of the alveoli

Alveolar macrophage

Phagocytic cells roaming around the alveolar wall, which removes debris and pathogens that have reached the alveoli

respiratory Membrane

- Formed by the simple squamous epithelium of alveolus and that of capillaries.
- About 0.5 mm thick.
- Allows gases to cross by simple diffusion.
- Allow oxygen to be picked up by the blood for transport and CO2 to be released into the air of the alveoli

Lungs

- Pyramid-shaped organs connected to the trachea by the right and left bronchi.
- Bordered by the diaphragm inferiorly.
- Enclosed by the pleurae, which are
attached to the mediastinum.

cardiac notch

An indentation on the surface of the left lung, and allows space for the heart

apex of the lung

superior region of the lung

base of the lung

near the diaphragm

costal surface

borders the ribs

mediastinal surface

faces the midline

Superior, middle, and inferior lobes

Lobes of the right lung

Superior and inferior lobes

Lobes of the left lung

Fissures

Separates the two lung from each other

bronchopulmonary segment

- A division of a lobe.
- Each segment receives air from its own tertiary
bronchus.
- Supplied with blood by its own artery

Blood supply of the lungs

- Plays an important role in gas exchange.
- Serves as a transport system for gases throughout the body

Innervation by both the parasympathetic and sympathetic
nervous system

Provides an important level of control through dilation and constriction of the airway

The pulmonary artery

- Arises from the pulmonary trunk and carries deoxygenated, arterial blood to the alveoli.
- Branches follow the bronchi.
- Each branch becomes progressively smaller in diameter.

pulmonary capillary network

- Consists of tiny vessels with very thin walls that lack smooth muscle fibers.
- Branch and follow the bronchioles and structures of the alveoli.
- At this point, the capillary wall meets the alveolar wall, creating the respiratory membrane.

Hilum

Once the blood is oxygenated, it drains from the alveoli by way of multiple pulmonary veins, which exit the lungs through the \__________.

Autonomic nervous system

- Controls Parasympathetic & Sympathetic
- Controls reflexes such as coughing.
- Regulate oxygen and carbon dioxide levels

Parasympathetic

causes bronchoconstriction

Sympathetic

stimulates bronchodilation

Sensory nerve fibers

Arise from the vagus nerve, and from the second to fifth thoracic ganglia.

Pulmonary plexus

- A region of the lung root formed by the entrance of the nerves at the hilum.
- Innervate muscle fibers, glands, and blood vessels

Pleura of the lungs

- A serous membrane that surrounds the lung.
- The right and left pleurae are separated by the mediastinum.
- Produce pleural fluid and create cavities that separate the major organs.

visceral pleura

The layer that is superficial to the lungs, and extends into and lies the lung fissures

parietal pleura

The outer layer that connects to the thoracic wall, the mediastinum, and the diaphragm

pleural cavity

The space between the visceral and parietal layers

Pleural fluid

- Lubrication reduces friction between the two layers to prevent trauma during breathing.
- Creates surface tension that helps maintain the position of the lungs against the thoracic wall.
- Causes the lungs to enlarge when the thoracic wall expands during ventilation.

mesothelial cells from both layers

Secretes pleura fluids

Pulmonary ventilation

- The act of breathing, which can be described as the movement of air into and out of the lungs
- In a gas, pressure is a force created by the movement of gas molecules that are confined

Inspiration (or inhalation) and expiration (or exhalation)

Dependent on the differences in pressure between the atmosphere and the lungs

Ventilation control center

- Multiple regions in the brain signal the muscles used in pulmonary ventilation to contract.
- Result in a rhythmic, consistent ventilation rate.
- Provides the body with sufficient amounts of oxygen, while adequately removing carbon dioxide

The medulla oblongata & The pontine respiratory group

major brain centers involved in the ventilation control center

The dorsal respiratory group (DRG)

- Involved in maintaining a constant breathing rhythm by stimulating the diaphragm and intercostal muscles to contract resulting in inspiration.
- Stopping stimulation will cause relaxation of the diaphragm and intercostals resulting in expiration.

The ventral respiratory group (VRG)

- Involved in forced breathing.
- Stimulate the accessory muscles involved in forced breathing to contract.
- Also stimulates the accessory muscles involved in forced expiration to contract