Introduction of Respiratory System
- the respiratory system is responsible for taking the proper amount of oxygen in the blood and removing the co2 from the blood.
- The respiratory tract is divided into the upper and lower respiratory tract
- Upper respiratory tract from the nose to the larynx
- Lower respiratory tract from the trachea to the bronchioles
- Respiratory tract is
- Conducting caution of the respiratory tract is responsible for the transport of air including (the nose and nasal cavity, pharynx, larynx, and trachea).
- The respiratory portion of the respiratory tract is responsible for carrying out the gas exchange.
Key Point
- The upper respiratory tract consists of – Nose to the larynx
- The lower respiratory tract consists of – Trachea to bronchioles
Nose Anatomy
- Nose pizza man route of air entry and the first part of the respiratory tract.
- Nose inspired the humidified, warm and filtered air
- The external opening of the nose is called the nares or nostrils.
- 3 prominence (nasal concha) -superior, middle and inferior
- 3 space (meatus)- superior, middle and inferior
- palette acts to separate the nasal cavity and oral cavity.
- nose hair helps to protect entering the dust particle into the respiratory tract from the environment.
Bones surrounded the nasal cavities
- Frontal bone
- Sphenoid bone
- Ethmoid bone
- Maxillary bone
Nasal cartilage
- Septal
- Lateral
- Minor alar
- Major alar
- Goblet cells responsible for secret mucus in the nose
- the shape of the nose depends upon the nasal bone formation and formation of the bridge of the nose
Blood supply – The nose receives blood supply from ophthalmic, maxillary and facial arteries
Key Point
- The external opening of the nose is called – Nostrils/nares
- Which cell is responsible for secreting mucus in the nose – Goblet cell
Larynx Anatomy
- Larynx also called the vocal cord or voice box
- The larynx is responsible for the production of voice sound
- a larynx is an air pass or organ, situated below the pharynx at the level of C3 to C6 vertebrae.
- Larynx size in males – 44 mm and females- 36 mm
- In puberty, the male larynx rapid growth the female larynx
- The larynx is generally composed of various irregular shapes of cartilages
- The larynx considers the 3 pairs and 3 unpaired cartilage.
- 3 paired cartilage are-
- Corniculate
- Arytenoid
- Cuneiform
- 3 unpaired cartilage are –
- Thyroid
- Cricoid
- Epiglottis
Thyroid cartilage
- the thyroid cartilage is a ‘V’ shape in cross-section and the most prominent laryngeal cartilage
- These cartilages is made of hyaline cartilage.
- Thyroid cartilage’s upper part is made by the stratified squamous epithelium and the lower part is made by ciliated columnar epithelium tissue.
Cricoid cartilage
- The cricoid cartilage is ring-shaped cartilage situated below the thyroid cartilage
- These cartilages also made of hyaline cartilage
- The cricoid cartilage is strong and thick cartilage than thyroid cartilage
- The narrow anterior part of the record cartilage is called the arch, and the posterior broad is called the lamina.
Epiglottis cartilage
- epiglottis cartilage is a leaf-shaped elastic flap structure, that is situated at the top of the larynx
- epiglottis help to prevent the food passes in the tracheobronchial tree and cover the glottis during swallowing
- It is a flexible and fibroelastic cartilage
- Epiglottis cause temporary apnea during eating
Arytenoid cartilage
- arytenoid cartilage is 2 small pyramid shaped cartilage, that are situated at top of the cricoid cartilage
- This cartilage is form the posterior part of the larynx
- There are two folds of mucous membrane on each side of the larynx
- The upper fold is a vestibular fold
- The lower fold is a vocal fold
Key Point
- Which body part is responsible for the production of voice sound – The larynx
- The larynx extends from – C3 to C6 vertebra
- Leaf shape elastic flap cartilage of larynx – Epiglottis
- Ring-shaped cartilage of larynx – Cricoid cartilage
- The lower fold of the larynx is a – Vocal fold
- Low pitch sound produced by the larynx in case – Vocal cord muscles are relaxed
Pharynx
- The pharynx is a common pathway for air and food passes.
- Pharynx located behind the oral and nasal cavity
- Pharynx age 12 – 14 cm long tube, that is extended from base of the skull to 6th cervical vertebra.
- The pharynx is divided into-
- Nasopharynx (from the base of the skull to the soft palate)
- Oropharynx (from the soft palate to C3 vertebra)
- Laryngopharynx (from C3-C6 vertebrae)
- Laryngopharynx is a caudal part of the pharynx and is also called the hypopharynx.
Muscles of pharynx
- It is divided into 2 groups
-
Longitudinal muscles
- Palatopharyngeus
- Stylopharyngeus
- Salpingopharyngeus
-
Pharyngeal constrictors
- Superior
- Inferior
- Middle
Pharynx Blood supply – pharynx receives blood supply from the external carotid artery
The external carotid artery is –
- Lingual artery
- Facial artery
- Maxillary artery
Pharynx Nerve supply – major 3 cranial nerves.
- Maxillary nerve
- Vagus nerve
- Glossopharyngeal nerve
Key Point
- Other names of laryngopharynx – Hypopharynx
Vocal Cord
- vocal cords are covered with mucous membrane, that is located below the larynx and at the top of the trachea.
- the vocal cord attached anteriorly with the thyroid cartilage posterior attach with arytenoid cartilage
- When vocal cord muscles relax, the larynx causes a low pitched sound.
- When vocal cord muscles contract, the larynx causes the High pitched sound.
- larynx divided into three parts due to vestibular and vocal fold-
- Vestibule of larynx- top part of vegetable fold.
- Sinus or sinus of ventricle of the larynx – between vestibular and vocal fold.
- Infraglottic part – below part of vocal fold.
Intrinsic muscle of the larynx
- Cricothyroid muscle
- Transverse arytenoid unpaired muscle
- Thyroarytenoid and thyroepiglottic muscles
- Posterior cricoarytenoid triangular muscle
- Oblique arytenoid and aryepiglottic muscle
- Lateral cricothyroid muscle
Vocal Cord Blood supply
- The larynx receives blood supply from the superior and inferior laryngeal artery
Vocal Cord Venous drainage
- venous drain by thyroid vein, that connect with internal jugular vein
Vocal Cord Nerve supply
- parasympathetic supply by the superior and recurrent nerve that is the branch of the vagus nerve.
Trachea Anatomy
- Also known as the windpipe
- trachea occupied the lower part of the neck and in the superior mediastinum
- the starting point of the trachea connects with the lower and of the larynx
- The isthmus of the thyroid gland is covering the trachea
- The trachea situated between the larynx and bronchus
- Length of trachea – 12 cm (10-15)
- Diameter of trachea – Male – 2cm Female – 1.5cm
- lover and off tracker divided into the right and left principal bronchi, at the level of T5 (carina) vertebral level.
- The right bronchus is slightly wider and more vertical than the left bronchus.
- Left bronchus is longer and narrower than right bronchus.
Structure of trachea
- The trachea is a cartilaginous structure of the middle respiratory tract.
- The trachea is extracted from the C6 vertebra to the T5 vertebra.
- 16 to 20 regular incomplete C-shaped hyaline cartilage rings provide the support of the trachea.
- These rings make the tubes convex anterolaterally.
- rings are incomplete at the posterior surface, which prevents the collapse of the trachea.
Trachea layers
- The outer layer (made of elastic tissue)
- The middle layer (made by smooth muscles)
- The inner layer (made of epithelium tissue)
Relation of trachea
- Anteriorly
- Brachiocephalic artery
- Aortic arch
- Lymph node
- Manubrium sterni
- Sternothyroid muscle
- Posteriorly
- Vertebral column
- Oesophagus
- Right side
- Azygos vein
- Right lungs and pleura
- Right vagus
- Left side
- Left common carotid artery
- Left subclavian artery and arch of aorta
- Tracheobronchial tree
Blood supply of Trachea
- The trachea receives blood supply from the inferior thyroid artery
Trachea Venous drainage
- Drain into left brachiocephalic vein
Trachea Nerve supply
- trachea receive nerve supply from sympathetic and parasympathetic laryngeal nerve
Teachea Lymphatic drainage
- Into paratracheal and paratracheal nodes.
Key Point
- Windpipe of respiratory tract – Trachea
- Average length of the trachea is – 12 cm
- Trachea is divided into right and left bronchus at the level of – T5 vertebra
- The trachea extends from – C6 vertebra to T5 vertebra
Lungs Anatomy
- Lungs are respiratory organs, occupying the thoracic cavity.
- Lungs cover the major portion of the thoracic cavity.
- lungs are spongy in texture and right and left are divided by the mediastinum.
- lungs are extended from just above the clavicle to the diaphragm
- Normal lung colour is the grey or brown but black colour of lungs due to deposition of carbon particles.
- Weight of lungs
- Right lung – 650 gm
- Left lung – 600 gm
- Thoracic cages (ribs) protect the lungs from injury.
- The pleura is a serous membrane that covers the lungs.
- The space between the parietal and visceral layer is called the pleural cavity.
- Pleural cavity filled with serous fluid
Parts of lungs
- Costal surface – it is the outer surface of the lungs, that is occupied against the costal cartilage. (large and convex shape service)
- Medial surface – medial surface area of lungs is face is the mediastinum. medial surface divided into posterior vertebral part and anterior mediastinal part.
Border of lungs
- Anterior border
- Posterior border
- Inferior border
Anterior border
- It is a very thin and shorter border than the posterior border
- These borders correspond to the pleural reflection
Posterior border
- It is a thick border
- Extend from C7 to T10
- help to separate the vertebral part of the medial surface from the costal part.
Inferior border
- The border helps to separate the base of medial and postal service.
Fissures in the lungs
- Fissures are helpful to divide each lobe into lobs.
- Right lungs consist two fissures-
- Horizontal fissures
- Oblique fissures
- Right lungs consist 3 lobes –
- Upper lobe
-
- Middle lobe
- Lower lobe
- Left lung consists 1 fissure – oblique fissure
- Left lung consists 2 lobe – upper and lower
Cardiac notch
- cardiac notch is an indentation on the left lung surface that provides the space for the lungs.
- It is occupied the anterior border of the left lung
Difference between right lung and left lung
| Right lung | Left lung |
| The anterior border is straight | The anterior border is interrupted due to cardiac notch |
| Consist 3 lobes | Consist 2 lobes |
| Shorter and broader | Longer and narrow |
| Consist 2 fissures | Consist 1 fissure |
| Weight about 650 gm | About 600gm |
| Provide the space for liver | Provide the space for heart |
| Lingula absent | Lingula present |
- Each lung consists that 10 bronchopulmonary segment
Hilum (roots of lungs)
- The hilum is a palace, where structures enter or leave the lungs.
- Roots of lungs situated opposite side of, 6th and 7th thoracic vertebra.
Contents
- Principal bronchus
- 2 pulmonary vein
- 1 pulmonary artery
- Bronchial artery and vein
- Areolar tissue
- Bronchopulmonary lymph node
Blood supply of lungs
- lungs receive the deoxygenated blood from the pulmonary artery and receive oxygenated blood from the pulmonary vein.
Nerve supply of lungs
- Parasympathetic nerve supply from the vagus nerve
- Sympathetic nerve supply from the 2nd and 5th sympathetic ganglia.
Key Point
- Which structure covers a major portion of the thoracic cavity – The lungs.
- The normal colour of the lungs – Gray, and brown colour.
- The pleural cavity is filled with – Serous fluid.
- Dome shaped part of the lungs is – Apex.
- A cardiac notch is an indentation of – Left lungs.
Diaphragm Anatomy
- The diaphragm is a chief regulatory muscle of respiration.
- The form is responsible to separate the thoracic and abdominal cavities.
- The diaphragm is a dome-shaped muscle.
- 75% inspiration done by diaphragm at resting period.
- Diaphragm muscles fibres
- Sternal
- Costal
- Lumbar
- Sternal muscle fibres arise from the back of the xiphoid process.
- Costal muscle fibres arise from the inner surface of the cartilage.
- Lumbar muscle fibre arises from lateral and medial costal arches.
- The right diaphragm is slightly higher.
- During inspiration, the diaphragm descends into the abdominal cavity.
- During expiration, diaphragms move upward in the thoracic cavity.
Opening of diaphragm
- The oesophageal opening.
- The aortic opening.
- Gastric and vagus nerve opening.
- Vena cava opening.
Diaphragm relation
Superiorly – pericardium, pleurae
Inferiorly – liver, stomach fundus
- Suprarenal and kidney
- Peritoneum
- Spleen.
Diaphragm blood supply –
- Diaphragm receive blood supply from inferior phrenic arteries, Musculo phrenic artery, pericardiophrenic artery
Diaphragm venous drainage –
Venous drain into the inferior phrenic vein and superior phrenic vein.
Diaphragm nerve supply –
The diaphragm receives nerve supply from phrenic and lowers intercostal nerves.
Key Point
- Chief regulatory muscles of respiration – Diaphragm
- Normal shape of diaphragm is – Dome shape
Lungs Volume
Tidal volume – normal respiration volume.
- Normal tidal volume about 500 ml.
- Tidal volume is an amount of air, which is inspired and expired during single respiration.
- Conductive airway – Airway from Rose to terminal bronchioles.
- Normal conductive airway tidal volume = 150 ml.
- Respiratory airway – airway from bronchiole to alveoli.
- Normal respiratory airway tidal volume = 350 ml.
Inspiratory reserve volume (IRV)
- IRV is an extra amount of air, which is inspired forcefully, after normal respiration.
- Volume = 3300 ml.
Expiratory reserve volume (ERV)
- ERV is an extra amount of air, which is expelled forcefully beyond tidal volume.
- Volume= 1000 ml.
Residual volume – The lungs cannot be empty completely even after the forcefully expiration.
- So residual volume is a remaining amount of air in the lungs after the forceful expiration.
- Volume = 1200 ml.
Key Point
- Normal tidal volume – 500 ml
- Normal residual volume of lung – 1200 ml
Lungs Capacity
- Vital capacity – Vital capacity is a maximum amount of forceful best battery volume after maximum inspiration.
VC = TV + IRV + ERV
= 500 + 3300 + 1000
= 4800 ml.
- Vital capacity also no timed Vital capacity.
- Inspiratory capacity – Maximum amount of forceful inspiratory volume after normal respiration.
IC = TV + IRV
= 500 + 3300
= 3800 ml.
- Total lung capacity – Maximum amount of air present in the lungs after the deep respiration.
TLC = TV + IRV + ERV + RV
= 500 + 3300 + 1000 + 1200
= 6000 ml.
- Residual capacity – Functional residual capacity is the volume of air, that is present in the lungs at the end of the passive expiration.
FRC = ERV + RV
= 1000 + 1200
= 2200 ml.
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