CHAPTER VIII PDL 101 HUMAN ANATOMY & PHYSIOLOGY
Ms. K. GOWRI. M.Pharm., Lecturer.
Respiratory system Introduction:
‐ Cells of body need energy for activity to maintain homeostasis and this is obtained by oxygen.
‐ Releases oxygen
‐ The organs of respiratory system are 1. Nose 2. Pharynx 3. Larynx 4. Trachea 5. Two bronchi 6. Bronchioles 7. Two lungs and their coverings
‐ Intercostal muscles and diaphragm Æ respiration NOSE AND NASAL CAVITY:
‐ Position and structure
‐ Contains large irregular cavity divided into two equal
passage by a septum.
‐ Hyaline cartilage
‐ Roof, floor, medial plane, lateral walls, posterior walls.
‐ Lining of nose – ciliated columnar epithelium consists
goblet cells.
‐ Openings into the nasal cavity Æanterior nares, posterior
nares, paranasal sinuses. ‐ Maxillary sinuses and frontal and sphenoidal, ethmoidal
sinuses are present.
Respiratory functions of nose:
‐ Air is warmed, moistened and filtered.
‐ Humidification.
‐ Olifactory function of nose.
‐ Olifactory nerves to brain Æ sensation of smell. Pharynx:
‐ Position – 12‐14cm long.
‐ 6th cervical vertebrae
‐ Structure – superiorly — inferior surface of skull. – inferiorly – continuous with the oesophagus. – anteriorly – the wall is incomplete because of nose, mouth and larynx. – posteriorly—areolar tissue, involuntary muscle.
‐ Nasopharynx Æ auditory tubes pharyngeal tonsils.
‐ Oropharynx Æ palatine tonsil, uvula.
‐ Laryngopharynx Æ 3rd to 6th cervical vertibrae. Structure:
1. Mucous memerane lining 2. Fibrous tissue 3. Muscle tissue
‐ Blood and nerve supply. Functions:
‐ Passage way for air and food ‐ Warming and humidifying
‐ Taste
‐ Hearing
‐ Protection
‐ Speech Larynx:
‐ Position – voice box.
‐ Structure – superior – hyoid bone and tongue
– inferior – trachea – anterior – muscles of neck – posterior – 3rd and 6th cervical vertebrae – lateral – thyroid gland Structure:
‐ Cartilage – 1 thyroid cartilage
– 1 cricoid cartilage } hyaline cartilage
– 2 arthenoid cartilage
– 1 epiglottis – elastic fibro cartilage
‐ Ligaments and memberanes are present
‐ Blood and nerve supply Æ parasympathetic nerve supply
‐ Cervical ganglia one on each side
‐ Laryngeal arteries
‐ Inferior of the larynx – vocal cords, relaxationÆ abduction AductedÆ stretching Functions:
‐ Production of sound – pitch, volume, resonance
‐ Speech
‐ Protection of the lower respiratory track
‐ Passage way for air
‐ Humidifying, filtering and warming Trachea:
‐ Position Æ 5th thoracic vertebrae
‐ Structures – superior – larynx
– inferior – bronchi – anterior – isthmus, aorta – posterior – oesophagus . – lateral – lungs and lobes ‐ Contains 16‐20 C‐ shaped hyaline cartilages
‐ Three layers of tissue – outer layer
– middle layer – inner layer Functions:
‐ Support and patency
‐ Mucociliary escalator
‐ Cough reflex
‐ Warming, humidifying and filtering of air Bronchi & smaller air passages:
‐ Right and left bronchi
‐ Bronchi, bronchioles ‐ Their structure Æ terminal bronchioles, respiratory bronchioles, alveolar ducts, alveoli.
‐ Nerve and blood supply, lymph drainage.
‐ Arterial blood supply – right and left bronchial arteries.
‐ Lymphatic vessels and lymphatic nodes
‐ Functions of air passage not involved in gaseous exchange:
1. Control of air entry. 2. Warming and humidifying. 3. Support and patency. 4. Removal of particulate matter. 5. Cough reflex. Functions of respiratory bronchioles & alveoli: 1. Defence against microbes 2. Warming &humidifying Lungs:
‐ The apex, base, costal surface & medial surface are present
‐ Two lungs, cone shaped
‐ Pulmonary artery & two veins draining out
‐ Space between in mediastinum Organization of the lung:
‐ Right lung – superior, middle & inferior
‐ Left lung – two lobes – superior inferior
‐ Pleura & pleural cavity ‐ Visceral pleura, parietal pleura, pleural cavity
‐ Inferior of the lung
‐ Pulmonary blood supply – pulmonary artery, deoxygenated blood
‐ Two pulmonary veins Respiration:
‐ Inflation &diflation of lungs occurring with each breath ensures that regular exchange of gasses takes place between the alveoli & external air.
‐ Diaphragm – dome shaped separating thoracic & abdominal cavities Muscles of respiration:
‐ Intercostal muscles ‐ External intercostal muscles
‐ Internal intercostal muscles cycle of respiration:
‐ Inspiration Æ active & energy is needed three respiratory pump
‐ Expiration – relaxation Æ passive
‐ Pause – next cycle begins Physiological variables affecting respiration:
‐ Elasticity
‐ Compliance ‐ Airflow resistance
Lung volumes & capacities:
‐ 15 complete respiratory ctcles per minute
‐ Anatomical dead space
1. Tidal volume: about 500ml Æin & out 2. Inspiratory reserve volume – maximal inspiration 3. Inspiratory capacity – 500ml+ inspiratory reserve volume 4. Functional residual volume – amount remained after expiration 5. Expiratory reserve volume – largest volume of expiration 6. Residual volume – cannot be measured, remaining air 7. Vital capacity – max volume into & out Vc= tidal volume+IRV+ERV
‐ Alveolar ventilation= (TV‐anatomical dead space)xRR
= (500‐150)ml x 15 per min = 5.25 litr/min ‐ Composition of air:
‐ Mixture of gasses like nitogen, oxygen, carbondioxide, water vapour & small quantities of inert gasses.
‐ Alveolar air & expired air
‐ Diffusion of gasses
‐ External respiration
‐ Internal respiration
‐ Transport of gases in blood stream Oxygen:
‐ Oxyhaemoglobin
‐ In solution in plasma water
‐ 2,3‐diphosphoglycerate Æ Co2 & head Æincreased release of
O2
Co2:
‐ bicarbonate ions are formed in plasma.
‐ Dissolved in plasma.
‐ Carried in erythrocytes, carbaminohaemoglobin. Control of respiration:
‐ Respiratory centre
‐ Chemoreceptors Æ central chemoreceptor Æperipheral chemoreceptors
Other factors influensing respiration are:
1. speech, singing 2. emotional displays, eg—crying, laughing, fear 3. drug – sedatives, alcohol 4. sleep Disorders of the upper respiratory tract:
‐ Infectious & inflammatory disorders
‐ Common cold & influenza
‐ Sinusitis, tonsillitis, pharyngitis
‐ Laryngitis & tracheitis
‐ Diphtheria ‐ Hay fever Æ childhood onset asthma
Æ eczema in infants & young children Æ food allergies Tumours:
‐ Benign (haemangiomata)
‐ Carcinoma of the nose, sinuses, nasopharynx
Disease of bronchi:
‐ Acute bronchitis
‐ Chronic bronchitis
‐ Asthma Æ cold air
Æ cigarette smoking Æ air pollution Æ upper respiratory tract infection Æ emotional stress Æ strenuous exercise
‐ Bronchiectasis, emphysemia Æ pulmonary emphysemia
‐ Pneumonia – bronchopneumonia
– lobularpneumonia
‐ Lung absess
‐ Tuberculosis Æ mycobacterium tuberculae
Æ Pneumoconioses Æ due to industrial chemicals, silicosis, asbestos related diseases etc&
‐ Bronchial carcinoma, etc...
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