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7/29/2019 kumpulan slide kuliah batuk Univ muh yogyakarta

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Fisiologi Batuk

Ikhlas Muhammad Jenie


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Receptor

Afferent fibers

Central nervous

system

Efferent fibers

Effector

Reflex arc


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Physiologic mechanism to maintain the

tracheobronchila tree

1. Respiratory movement (passive or active)

2. The secretion from the bronchial glands

3. The ciliary activity of the epithelium liningthe trachea and bronchi

4. The cough reflex or the act of coughing


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Reseptor Batuk

Mekanoreseptor Chemoreseptor

Intrapulmoner Ekstrapulmoner

Slowly adapting receptor

(SAR)

Rapidly adapting receptor

(RAR)


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Mekanoreseptor

Low threshold mechanoreceptor

Activated by one or more mechanical stimuli

Generally do not respond directly to chemicalstimuli, unless the stimulus acts upon airway

structural cells to result in mechanical

distortion


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SAR and RAR

Originate in the nodose ganglia of the vagus

nerve

Terminate in the intrapulmonary airways and

lung parenchyma

Conduct AP in the A-range (10-20 m/s)


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SAR and RAR

Sensitive to:

Lung inflation (changes in lung volumes)

Bronchospasm (contraction of the smooth muscle

cells)

Airway wall oedema


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SAR

Display slowly adaptation --- a slow reduction in thenumber of action potential

Active during tidal inspiration, peaking just prior to

the initiation of expiration

Involved in the Hering-Breuer reflex, which

terminates inspiration and initiates expiration when

the lungs are adequately inflated

Antagonize cholinergic drive to the airway smoothmuscle, resulting in a reduction in airway tone


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RAR

Display rapidly adaptation --- a rapid reduction

in the number of action potential during

sustained lung inflation

Active during both inflation and deflation of

the lungs (including lung collapse)

Evokes tachypnea and airway smooth muscle

contraction (bronchospasm)


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Extrapulmonary

low threshold mechanoreceptors

Sensitive to punctate mechanical stimuli (such

as touch)

Insensitive to:

Physiologically-relevant tissue stretching

Changes in luminal pressure

Airway smooth muscle contraction

Slower conduction velocity (5 m/sec) in the

range of A-nerve fiber


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Extrapulmonary

low threshold mechanoreceptors

Originate also from the nodose ganglia of the

vagus nerve

Located in the extrapulmonary airways:

Larynx

Trachea

Large bronchi

May not be activated during normal breathing


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Chemoreceptors

Generally quiescent in the normal airways,becoming recruited during airways

inflammation or irritation

Derived from both the nodose and jugularvagal ganglia, as well as from the dorsal root

ganglia

conduct action potentials in the C and A-fiberrange

Sometime, it is called high threshold

mechanoreceptors


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Afferent fibers of coughing reflex

From the receptors in the pharynx, the impulse is

propagated along the afferent fibers of the

glossopharyngeal nerve (the IXth cranial nerve)

From the receptors in the larynx, trachea, and largerbronchi, the impulse is propagated along the

afferent fibers of the vagus (the xth cranial nerve)

[and also through n.laryngeus superior]

The ascending impulse is to reach the nucleus of

tractus solitarius (NTS)


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Cough Center

Medulla oblongata (brain stem) near the

respiratory center

Receptors in MO:

Opioid receptors

5-hydroxytryptamine receptors (5HT1A)

GABA receptors

NMDA antagonist

(N-methyl-D-asparate)


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Efferent fibers of coughing reflex

The descending fibers arising from NTS to the

spinal primary motor neurons and n.laryngeus

recurrence.


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Effectors

Laryngeal muscles

Diaphragm

The intercostal muscles The abdominal muscles


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The action of cough

The air is inspired (2.5 L)

The epiglottis is closed, and the vocal cords

shut tightly to entrap the air within the lungs

The abdominal muscle contract forcefully,

pushing against the diaphragm, while other

expiratory muscle contract forcefully the

pressure in the lungs > 100 mmHg


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The action of cough (2)

The vocal cords and epiglottis suddenly

opened widely, so that the air under pressure

in the lungs explodes outward (velocity 75

100 miles/ hour)

The rapidly moving air usually carries with it

any foreign matter that is present in the

bronchi or trachea


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The act of cough

Deep inspiration

Glottis is closed

Forced expiratory effort against

the closed glottis

Raised intrathoracic & intraabdominal

pressure

Glottis is suddenly opened

A drop in intralaryngeal pressure

Increased air flow (axial & radial)

Brief violent rush of air out of trachea

(800 km/h)


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Sites for eliciting cough

The origins of cough are part of respiratory tract:

Pharynx

Larynx (the endings of n.laryngeal superior)

Trachea (at the bifurcation or carina)

Segmental bronchi

Others:

External ear

Pleura Esophagus

Abdominal organs


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Stimulus for cough

Abnormal secretion within respiratory tract

Edema or ulceration of respiratory mucous

membrane

Irritation produced by foreign bodies Pressure from outside of respiratory tract

(mediastinal tumor, aortic aneurysms, Hodgkins

disease)

Pressure upon the recurrent laryngeal nerve

Irritation of the pleural surface (pleurisy,

effusion)


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Clinical cough

Acute and chronic non-asthmathic cough

Postnasal drip syndrome

Asthma Gastro-esophageal reflux

Chronic bronchitis

Angiotensin-converting enzyme inhibitors(ACE inhibitors)


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Clinical cough (2)

Others:

Pharyngitis

Pulmonary congestion

Pulmonary tuberculosis

Intrathoracal malignancies

Pleural effusion

Pleurisy


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