RESPIRATORY SYSTEM

The Anatomy and Physiology of the Respiratory System

WHAT IS HUMAN RESPIRATION?

  • Human respiratory system allows one to obtain oxygen, eliminate carbon dioxide
  • Breathing consists of two phase
      * Inspiration - the process of taking in air
      * Expiration - the process of blowing out air

 

 

 COMPONENTS OF THE UPPER RESPIRATORY TRACT

Upper respiratory tract function

  • Passageway for respiration
  • Receptors for smell
  • Filters incoming air to filter larger foreign material
  • Moistens and warms incoming air
  • Resonating chamber for voice

 COMPONENRS OF THE LOWER RESPIRATORY TRACT

Lower respiratory tract functions

  • Larynx - maintains an open airway, routes food and air appropriately, assists in sound production
  • Trachea - transports air to and from lungs
  • Bronchi - branch into lungs
  • Lungs - transport air to alveoli for gas exchange

 Gas exchange between the blood and alveoli

 Respiratory Cycle

 Measurement of Lung Capacity

 

FOUR RESPIRATION PROCESS

  • Breathing (ventilation) - air into and out of lungs
  • External respiration - gas exchange between air and blood
  • Internal respiration - gas exchange between blood and tissues
  • Cellular respiration - oxygen use to produce ATP, carbon dioxide as waste

Functions of the Respiratory System

  • Air Distributor
  • Gas exchanger
  • Filters, warms, and humidifies air
  • Influences speech
  • Allows for sense of smell

Divisions of the Respiratory System

Upper respiratory tract (outside thorax)

  • Nose
  • Nasal Cavity
  • Sinuses
  • Pharynx Larynx

   

Divisions of the Respiratory System

Lower respiratory tract (within thorax)

  • Trachea
  • Bronchial Tree
  • Lungs

   

Structures of the Upper Respiratory Tract

Nose - warms and moistens air

  • Palatine bone separates nasal cavity from mouth
  • Cleft palate - Palatine bone does not form correctly, difficulty in swallowing and speaking.
  • Septum - separates right and left nostrils
      * rich blood supply = nose bleeds
  • Sinuses - 4 air containing spaces – open or drain into nose - (lowers weight of skull).

Pharynx (throat)

  • Base of skull to esophagus

  3 divisions

  • Nasopharynx - behind nose to soft palate.
      * Adenoids swell and block.
  • Oropharynx - behind mouth, soft palate to hyoid bone.
      * tonsils
  • Laryngopharynx - hyoid bone to esophagus.

• Changes shape to allow for vowel sounds = phonation.

Larynx

  • voice box
  • Root of tongue to upper end of trachea.
  • Made of cartilage

  2 pairs of folds

  • Vestibular - false vocal cords

  • True vocal cords

 

Thyroid cartilage

  • Adam’s apple
  • larger in males due to testosterone.

Epiglottis

  • flap of skin (hatch) on trachea, moves when swallowing and speaking and closes off trachea when swallowing food

Trachea (windpipe)

  • Larynx to bronchi
  • Consists of smooth cartilage and C shaped rings of cartilage.
  • Tracheostomy - cutting of an opening in trachea to allow breathing.

  Bronchi

  • Tubes that branch off trachea and enter into lungs
  • Ciliated– WHY?
  • Branches: Primary bronchi — secondary bronchi — tertiary bronchi — bronchioles – Bronchioles branch into microscopic alveolar ducts. Terminate into alveolar sacs – Gas exchange with blood occurs in sacs.

 Lungs

  • Extend from diaphragm to clavicles
  • Divided into lobes by fissures.
  • Visceral pleura adheres to the lungs
  • Pleurisy = inflammation of the pleural lining (Plural – bronchi)

 

Respiratory Physiology

  • Pulmonary Ventilation = breathing
  • Mechanism
      * Movement of gases through a pressure gradient - hi to low.
  • Inspiration - When atmospheric pressure (760 mmHg) is greater than lung pressure ---- air flows in
  • Expiration - When lung pressure is greater than atmospheric pressure ---- air flows out

 

  • Pressure gradients are established by changes in thoracic cavity.
  • increase size in thorax = a decrease in pressure --- air moves in.
  • Decrease size in thorax = increase in pressure --- air moves out.

 

 

  • Inspiration - contraction of diaphragm and intercostal muscles

 

  • Expiration - relaxation of diaphragm and intercostal muscles
Volumes of Air Exchange

• Tidal volume

- amount of air exhaled normally after a typical inspiration. (about 500 ml)

• Expiratory Reserve volume

- additional amount of air forcibly expired after tidal expiration (1000 - 1200 ml).

• Inspiratory Reserve volume

- (deep breath) amount of air that can be forcibly inhaled over and above normal.

• Residual volume

- amount of air that stays trapped in the alveoli (about 1.2 liters).

• Vital capacity

- the largest volume of air an individual can move in and out of the lungs.

• Vital capacity = sum of IRV+TV+ERV

Depends of many factors

• size of thoracic cavity

• posture

• volume of blood in lungs

  • congestive heart failure, emphysema, disease, etc.

• Eupnea

- normal quiet breathing, 12-17 breaths per minute.

• Hyperpnea

- increase in breathing to meet an increased demand by body for oxygen.

• Hyperventilation

- increase in pulmonary ventilation in excess of the need for oxygen.

Someone hysterical (exertion) → Breathe into paper bag.

• Hypoventilation - decrease in pulmonary ventilation.

• Apnea - temporary cessation of breathing at the end of normal expiration.

Heimlich Maneuver

  • Lifesaving technique that is used to open a windpipe that is suddenly obstructed.
  • Air already in lungs used to expel object.

 

Technique - Conscious victim

– Ask the victim if he/she can talk

– Stand behind victim and wrap your arms around their waist

– Make a fist with one hand and grasp it with the other hand

– Place thumb side of fist below xiphoid process and above navel.

– Thrust your fist in and upward - about 4 times.

  • DO NOT press on ribs or sternum

Technique - Unconscious victim

• Catch victim if they begin to fall - place on floor face up.

• Straddle hips

• Place one hand on top of other on the victims abdomen - above navel and below xiphoid process.

• Forceful upward thrusts with heel of hand - several times if necessary.