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

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

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

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.