Respiratory System

Respiratory System

1. Anatomy

   • Clear, open pathway from extrenal surroundings to lungs for Air
   • Stretchy Structures and organs = air movement and distribution
   • Large surface area = rapid diffusion to blood
   • Trauma to one lung may not affect the other
   • Apex of lung is superior to the rest of the lung and extends past the clavicles
   • The concave base of the lungs rests of the diaphragm
   • Lung has 2 or 3 lobes and these are dicided by fissures
   • Pleural membrane
     • Visceral Pleura covers lung
     • Parietal Pleura lines thoracic cavity wall
     • Serous fluid in Pleural cavity
       • Reduce friction during breathing
       • membranes to adhere each other
     • Mechanical coupling = both layers move together when breathing

2. Function

   • Gas exchange in lings between Alveoli and blood
   • Ph Regulation - CO2 concentration
   • Sense of Smell
   • Voice Production
   • Helps Venous blood and Lymph back to heart

3. Structure

   • Upper Respiratory Tract
     • Nose
       • Bone
       • Cartilage
       • Nostril - Bounded laterally by flared alae
     • Nasal Cavity
       • Mucous Membrane lined
       • Ciliated cells
       • Sensory nerve endings present = Sneezing
       • Blood capillaries and thin walled veins
       • Nasal cavity dicided by septum = part bone and part cartilage
       • Nasal conchae from lateral wall
         • Increase surface area
         • generate turbulence = warm and moisten inspired air
     • Phranyx
       • Nasopharynx
         • Pharyngeal tonsils (adenoids)
           • destroy/trap pathogens
         • Auditory tube
           • Drains the middle ear
           • middle ear pressure = atmospheric pressure
       • Orthopharynx
         • palatine tonsils
         • lingual tonsil
         • posterior to oral cavity
       • Laryngopharynx
         • opens to larynx anteriorly
         • open to oesophagus posteriorly
   • Lower Respiratory tract
     • Larynx
       • Passageway - connects Larynchpharynx to Trachea
       • Thyroid Cartilage (adams apple)
       • Epiglottis
         • Anchored by anterior rim of thryoid cartliage
         • Mucous Membrane coverage
         • Guards entrance of Glottis
         • Breathing = held open anteriorly
         • Swallow = pulled back to close off glottic opening
       • Glottis
         • Vocal cords that vibrate produce sound is here
       • Passage for air
       • Vocal cords = sound
       • initiate cough reflex
       • switching mechanism = swallowing and breathing opening
     • Trachea
       • passage for air
       • From Larynx and divides into 2 main brochi in lungs
       • Cilia = propel debris-laden mucous towards external
         • smoking damages cilia
       • Elastic tissue = flexible
       • sub-mucousal layer
       • Cshaped cartilage rings
       • Leads to Carina = sensitive = coughing if foreign objects makes contact
     • Primary Bronchi
       • Rings of C shaped cartilage
         • Does not collapse
       • Right is more wider and short and more vertical
         • risk of foregin object being inhaled and stuck is higher
     • Bronchioles
       • Connects to Tertairy bronchi and Alveoli
       • Cartliage replaced by smooth muscles
         • controlled by autonomic nervous system
       • Mucous producing cells and cilia sparse
       • airflow can be heard at posterior or anterior chest = make it easier to hear adventitious sound
       • Simple cuboidal epithelium replaces cili cells = diffusion of gases to blood and vice versa
     • Alveoli
       • Pulmonary Lobules
         • Wrapped in elastic tissue
         • around alveolus
         • lymphatic vessel
         • an arteriole
         • a venule
         • a Terminal Bronchiole
         • Alveolar sac
       • Large surface are for gas to exchange with blood
       • Lined with simple squamous epithelium for effiecient diffusion
       • Rich supply of blood capiliaries and fluid around each alveolus (pulmonary lobules)
       • Moist = contains surfactant to lower surface tension
       • Surfactant prevents alveolar collapse
       • Macrophages remove particles from alveoli
     • Secondary Bronchi
       • Supply all 3 lobes in the RIGHT lung
       • Supply all 2 lobes in the LEFT lung
       • Rings of cartilage replaced by strips of cartilage
     • Tertiary Bronchi
       • Supply lobes of each lung
       • Strips of cartilage
   • CN I = Olfactory Neurons
     • Sense of smell
     • Stimulated by odour
     • axons travel up through bones in the bones superior to nasal cavity

4. Physiology

   • Pressure Gradient = air flow
   • Filter and humidifies air particles = prevention of microbes into Lungs
   • O2 and CO2 effieciently exchanged between atmosphere and blood

5. Imbalance of Homeostasis

   • Viral and Bacterial infections cause inflammation of mucous membrane (nasal cavity)
     • excess mucus production
     • Nasal Congestion
     • Postnasal Drip
     • Upper Resp tract infections
   • Sinusitis = infections may spread to paranasal sinuses
     • infectious material block passageway
     • air absorbed = vacuum
     • causes sinus headaches over inflammed area
   • Laryngitis
     • Inflammation of vocal cords
     • Vocal cords swell = disturbing vibration
       • Produce hoarse sounds
       • whisper
     • Infection
     • Overuse of voice
     • Irritants e.g smoke/cigarette

6. Cell Respiration

   • Aerobic respiration
     • Uses Glucose and O2
     • Produces CO2 , heat and many ATP
   • Anaerobic respiration
     • Uses Glucose
     • Produce minimal ATP and Pyruvic Acid
     • Production of Lactic Acid

7. Ageing

   • Airways, tissues = less elastic, more rigid.
   • Reduce Vital capacity
   • Reduce O2 and its level. unable to excercise vigourously