Unit 16 Respiratory System

PRIMARY FUNCTIONS

1. Exchange gases (oxygen and CO₂)

2. Produce vocal sounds

3. Sense of smell

4. Regulate blood pH

Respiration = process of gas exchange

External respiration  = air enters the lungs,  (air → blood)
Internal respiration = blood travels to body parts and exchanges gas with those tissues (blood → tissues)

Does CF cause a problem with internal or external respiration? External because the mucus buildup reduces her function to breath as described in the diary.

Why do we need oxygen?

Cellular respiration  =  cells use oxygen and sugars to create energy in the form of ATP

    *ATP is then used to power cellular processes

Upper Respiratory Tract – nose, nasal cavity, sinuses, pharynx
Lower Respiratory Tract – larynx, trachea, bronchial tubes, lungs

Nasal concha – bones that divide the nasal cavity, support the mucus membrane and increase surface area (superior, middle, inferior) 

Mucus Membrane - warms and moistens air, also traps dust and other particles

Paranasal Sinuses - spaces within the bones

They are named after the bones: 

• maxillary

• frontal

• ethmoid

• sphenoid

  reduce the weight of skull and are resonant chambers for voice.

Pharynx – behind the oral cavity, between the nasal cavity and larynx (space, not a structure)

Epiglottis - this flap closes when you swallow, preventing food from going into the airway.

Heimlich maneuver - used to save someone who is choking.

Larynx – enlargement at the top of the trachea, houses vocal cords.

Composed of muscles and cartilage

GLOTTIS: part of the larynx consisting of the vocal cords 

- false vocal folds  – close airway during swallowing

- true vocal folds - produce sound

LARYNGITIS

Inflammation of the larynx that  makes the voice hoarse

Caused by illness, allergies, smoking, some medications.

If you have chronic laryngitis, you might want to see an…
OTOLARYNGOLOGIST: Ear, nose, and throat doctor

Laryngoscope: Used to visualize the Larynx and structures surrounding the throat.

Trachea  (windpipe)

• cylinder with stiff cartilage to keep it from collapsing

• Trachea leads to  the BRONCHIAL TREE

Goes from…

Trachea →   Primary bronchi  →   Secondary bronchi → Tertiary bronchi → Bronchiole

Bronchioles have air sacs called alveoli which are connected to the circulatory system via capillaries.

1. Channels in the epithelium move chlorine ions out of the cell.

2. If those channels are “broken”, chlorine builds up  which attracts water (osmosis!).

3. This water causes a thick mucus to build up extracellular space, restricting air flow. 

Respiratory Epithelium -  In CF patients, the CFTR channel is broken, this causes what problem? Respiratory failure and then death.

LUNGS - spongy tissue that sit within the pleural cavity

• Right Lung
           = 3 lobes

• Left Lung
            = 2 lobes

• Cardiac notch - space for heart

• Serous fluid lubricates lungs during breathing

Breathing Mechanism

1. Diaphragm moves down, forcing air into airways
2. Intercostals contract, enlarging cavity.
3. Surface tension in alveoli and surfactant keep air sacs from collapsing
4. Other muscles force a deeper breath.
5. Relaxing the diaphragm causes elastic recoil (exhalation)

Why is the first breath of a newborn the most difficult?  Due to the lack of surfactant

Respiratory Cycle = one sequence of inhalation and exhalation

1. Inspiration - air enters the lungs 
                       (inhale)

2. Expiration - air leaves the lungs 
                       (exhale) 

• Inspiration occurs when muscles of the diaphragm change the pressure in the pleural cavity, causing air from the outside to enter the lungs. 

Respiratory rate for for adults is 12-18 breaths per minute

Respiratory Air Volumes:

Spirometry - measures the amount (volume) of air moving in and out of the lungs.

Resting Tidal Volume =  amount of air that enters the lungs during one cycle

   *take a normal breath

Vital Capacity (lung capacity)

the amount of air that can be forced in or out by taking a deep breath.

A = tidal volume 

B = vital capacity

FEV1 =  Forced expiratory volume in 1 second is an established marker of cystic fibrosis (CF) disease progression

Factors that can Affect Breathing

1. Rise in CO₂
2. Emotional upset, fear and pain
3. Low blood oxygen

Hyperventilation - increased breathing, lower CO₂ concentration

Respiratory Membrane 

Gas exchange occurs across a membrane - a layer of simple squamous cells

Oxygen DIFFUSES into the bloodstream

*Alcohol can be detected in breath

Hypoxia is a disease in which there is an overall lack of oxygen content within the body's tissue and vital human organs (specifically the brain). 

Blue skin is an indication of hypoxia, also called cyanosis.

Asphyxia deficient supply of oxygen that arises from being unable to breathe normally. 

*An example of asphyxia is choking. 

Career: Respiratory Therapist

2021 Median Pay

     $61,830 per year 

     $29.73 per hour

Typical Entry-Level Education: Associate's degree 

Number of Jobs, 2021: 135.800

Job Outlook, 2021-31: 14% (Faster than average)

ILLNESSES RELATED TO THE RESPIRATORY SYSTEM

COPD = Chronic obstructive pulmonary disease

*Most commonly caused by smoking

Bronchitis = inflammation of the main air passages to the lungs

Bronchitis may be short-lived (acute) or chronic, meaning that it lasts a long time and often recurs.

Sleep Apnea = Pause or slowing of breathing during sleep

Pulmonary Embolism
- a blood clot that moves to the lungs

- this can cause shortness of breath, rapid heartbeat

- hypoxia

Lung Cancer

Lung cancer starts when abnormal cells grow out of control in the lungs. 

There usually are no signs or early symptoms of lung cancer. 

As lung cancer stages advance, lung cancer symptoms may include:

• Coughing

• Wheezing

• Shortness of breath

• Bloody mucus

Altitude Sickness = Atmospheric Pressure is necessary for breathing

Lack of pressure on mountains can be dangerous.  Hundreds of bodies are lying on Mount Everest

Case Study - How Do Tibetans Survive at High Altitude? 

Genetic Adaptations:

• EPAS1: Plays the role in regulating red blood cells and hemoglobin levels

• EGLN1: Involved in the oxygen homeostasis system

Physiological Adaptations:

• Low Hemoglobin Concentrations: Maintain low hemoglobin levels which makes people less susceptible to altitude sickness.

• Wider Blood Vessels: enhances oxygen levels to tissues

• Nitric Oxide: Exhale more nitric oxide → vasodilation(widened blood vessels) → improved blood flow and transportation

• Increased Lung Capacity: Better lungs and response to respiration

Asthma = Inflammation of bronchial tubes, increased production  of sticky secretions.

Symptoms:

• coughing

• wheezing

• shortness of breath

• chest tightness

• pain or pressure

  Bronchodilators are used to open airways.

Bacterial or Viral Infections: Pneumonia, influenza, rhinovirus, Covid-19.

Whooping Cough (Pertussis)

Causes serious coughing and gasping for breath, dangerous for infants.  

Pneumothorax - Collapsed Lung

- pressure from fluid in the pleural cavity deflates lung

- causes breathing difficulties

- treatment includes draining fluid from the cavity

Covid-19

- primarily affects lungs

- some patients are INTUBATED and placed on a VENTILATOR

- There is a vaccine!

Cystic Fibrosis - hereditary disease, mucus clogs the lungs, making it difficult to breathe and causing infections

If both parents are carriers, what is the chance they will have a child with the disease? A 25% chance

Treatment of Patients with Cystic Fibrosis:

• Antibiotics

• Medicines to reduce mucus

• Medicines to widen airways

• Medicines to absorb food better (GI tube)

• Medicines to increase movement of Cl+ across membranes

• Lung transplant

*Average lifespan is 44 years