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 are 1. Nose 2. 3. Larynx 4. Trachea 5. Two bronchi 6. Bronchioles 7. Two lungs and their coverings

‐ Intercostal muscles and diaphragm Æ respiration NOSE AND :

‐ 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, . ‐ 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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