ashish seminar

8/4/2019 Ashish Seminar

1/45

ANATOMY OF LARYNX &

TRACHEOBRONCHIAL

TREE AND CONTROL OF

BREATHING

-Dr Ashish Pareek

1st year residentDept of Anaesthesiology


2/45

23-2

Respiratory System


3/45

Lower Airway

Larynx

Tracheobronchial Tree (TB Tree)

Trachea

Bronchi

Bronchioles

Respiratory

Terminal


4/45

Larynx

Voice Box

Function

Prevents aspiration

Generates sound for speech

Conducts air between the pharynx andtrachea

Creates pressure changes


5/45

Cartilages of the Larynx

Composed of nine cartilagesThree unpaired cartilage

Thyroid

Cricoid Epiglottitis

Three paired cartilages (six total)

Arytenoid

Corniculates

Cuneiforms


6/45


7/45


8/45

Thyroid Cartilage

The largest laryngeal cartilage is thethyroid cartilage

Adams Apple

Superior border has a V-shaped notch.

Suspended from hyoid bone.

Posterior wall is open.

The true and false vocal cords are found on

the interior of the larynx.


9/45


10/45

Cricoid Cartilage

Resembles signet (class) ring.

Inferior to Thyroid.

Only complete ring of laryngeal structures.

Inferior border is attached to the first C-shaped tracheal ring.

The narrowest portion of the airway in aninfant.

We use this fact when ventilating infantsas infant ET tubes do not have cuffs toseal the trachea.


11/45

Epiglottis

Spoon-shaped cartilagewhich preventsaspiration by covering

the opening of thelarynx duringswallowing.

The tongue and the

epiglottis are connectedby folds of mucousmembranes which forma small space called the

vallecula.


12/45

Paired Cartilages

The Arytenoids, Cuneiforms, and Corniculatesare all associated with movement of the vocal

cords and are used in phonation.


13/45

Vocal Cords

Two pairs of folds that protrude inward:

Upper pair False cords

Lower pair True cords

The space between the vocal cords is called

the rima glottidis or glottis

Narrowest portion of the adult airway


14/45

Vocal Cords


15/45

Vocal Cords

Vocal Cord AbductionCords are opening or moving away from

the midline

This occurs during inspiration

Vocal Cord Adduction

Cords are moving toward the midline or

coming together

This occurs during expiration


16/45


17/45

Histology of the Larynx

Above the vocal cords

stratified squamous epithelium

Below the vocal cordspseudostratified columnar

epithelium

Trachea to respiratory bronchioles


18/45

Muscles of larynx

Cricothyroid

Posterior cricoarytenoid

Lateral cricoarytenoid

Transverse arytenoid Oblique arytenoid

Aryepiglotticus

Thyroarytenoid

Thyroepiglotticus

Vocalis


19/45

Nerve supply of larynx

Motor nerves

All the muscles of larynx are supplied by the

recurrent laryngeal nerve except cricothyroidwhich is supplied by external laryngeal nerve

Sensory nerves

Internal laryngeal nerve- upto level of vocal foldReccurent laryngeal nerve- below vocal fold


20/45

Blood supply & lymphatic drainage of

larynx

Upto vocal folds - sup laryngeal artery & vein

- anterosuperior group of

deep cervical lymph nodes

Below vocal fold - inf laryngeal artery & vein

- posteroinferior group of

deep cervical lymph nodes


21/45

Applied anatomy

Laryngospasm

A laryngeal reflex which will close thevocal cords inside the larynx

Laryngospasm results from

Extubations

Near drowning

Inhalation of noxious substances

Smoke inhalation


22/45

Tracheobronchial Tree

Two DivisionsCartilaginous Airways

Primarily conducting airways; no gasexchange.

Trachea to terminal bronchioles which isciliated for removal of debris, mucuslined

Noncartilaginous Airways Both conducting airways and sites of gas

exchange.


23/45

Cartilaginous Airways

Trachea

Main Stem Bronchi

Lobar Bronchi

Segmental Bronchi

Subsegmental Bronchi


24/45

Lobar Bronchi


25/45

Trachea

Generation 0

11 13 cm long and 1.5 2.5 cmwide.

Extends from Cricoid cartilage (6

th

cervical vertebrae) to the 2nd costalcartilage (5th thoracic vertebrae).

15 -2

0 C-shaped cartilages supportsthe trachea.

Posterior wall is contiguous withesophagus.


26/45

The end of the trachea is called thecarina.

This is the division of the trachea intothe right and left mainstem bronchi.

The carina is located at approximatelyT5 or the Angle ofLouis.

The surgical opening into the trachea iscalled a tracheostomy.

2nd or 3rd tracheal ring.


27/45

Main Stem Bronchi Generation 1

Trachea divides into the right and leftmainstem bronchi one for each lung

Right Mainstem is wider, shorter and

more verticalBranches at a 25 degree angle

LeftMainstem

Branches at a 40 60 angle Infants

Both mainstem bronchi form a 55

angle with the trachea


28/45

Newborn


29/45

Applied-Complications of Intubation

During intubations, if the tube is advanced tofar, the tube will usually go into the rightmainstem bronchi.

Lung inflation will be absent on the left but

present on the right. Withdraw tube until bilateral sounds are

heard.

Failure to hear lung sounds or visualize chestinflation on either side means the tube isprobably in the stomach.

Extubate the patient and re-attempt the

intubation.


30/45

Aspiration

Children who aspirate objects

Foreign body usually lodged in right

main stem bronchi secondary to theangle being less acute.

Wheezing on right or absent lung

sounds (breath sounds).


31/45

Lobar Bronchi

Generation 2

Lobar Bronchi correlate to the number of

lobes of the lung.

The right mainstem bronchi will divide

into the right upper, right middle and

right lower lobe bronchi.

The left mainstem bronchi will divide into

the left upper and left lower lobe

bronchi.


32/45

Segmental Bronchi

Generation 3

Correlate with the segments of the lung.

There are 10 segmental bronchi on theright.

There are 8 segmental bronchi on the

left.


33/45

Subsegmental Bronchi

4th to 9th Generations

1 to 4 mm in diameter

Connective tissue containing:Nerves

Lymphatics

Bronchial Arteries


34/45

Non-Cartilaginous Airways Bronchioles

10th to 15th Generation.

1 mm in diameter.

Simple cuboidal epithelium.

No cartilage.

Terminal Bronchioles

Less than 0.5 mm in diameter.

No cartilage (lack of support).

Cilia and mucous glands disappear.

Clara Cells appear


35/45

Blood Supply Bronchial Blood Supply

--Bronchial arteries nourish thetracheobronchial tree

--The arteries arise from the aorta and follow

the tracheobronchial tree as far as theterminal bronchioles.

--Beyond the terminal bronchioles pulmonary

arteries & capillaries feed the airways &alveoli.

--Normal bronchial blood flow is approximately

1% of the cardiac output.


36/45


37/45

23-37

Respiratory Areas in Brainstem

Medullary respiratory center

Dorsal groups stimulate the diaphragm

Ventral groups stimulate the intercostaland abdominal muscles

Pontine (pneumotaxic) respiratory group

Involved with switching between

inspiration and expiration


38/45

23-38

Respiratory Structures in Brainstem


39/45

23-39

Rhythmic Ventilation

Starting inspiration Medullary respiratory center neurons are continuously active

Center receives stimulation from receptors and simulation from parts ofbrain concerned with voluntary respiratory movements and emotion

Combined input from all sources causes action potentials to stimulate

respiratory muscles

Increasing inspiration More and more neurons are activated

Stopping inspiration

Neurons stimulating also responsible for stopping inspiration andreceive input from pontine group and stretch receptors in lungs.Inhibitory neurons activated and relaxation of respiratory musclesresults in expiration.


40/45

23-40

Modification of Ventilation

Cerebral and limbic

system

Respiration can bevoluntarily controlled

and modified by

emotions

Chemical control

Carbon dioxide is major

regulator

Increase or decrease in

pH can stimulate chemo-

sensitive area, causing a

greater rate and depth of

respiration

Oxygen levels in blood

affect respiration when a

50% or greater decrease

from normal levels exists


41/45

23-41

Modifying Respiration


42/45

23-42

Regulation of Blood pH and Gases


43/45

23-43

Herring-Breuer Reflex

Limits the degree of inspiration and prevents

overinflation of the lungs

Infants

Reflex plays a role in regulating basic rhythm of

breathing and preventing overinflation of lungs

Adults

R

eflex important only when tidal volume large as inexercise


44/45

23-44

Ventilation in Exercise

Ventilation increases abruptly At onset of exercise

Movement of limbs has strong influence

Learned component

Ventilation increases gradually

After immediate increase, gradual increaseoccurs (4-6 minutes)

Anaerobic threshold is highest level of exercisewithout causing significant change in blood pH

If exceeded, lactic acid produced by skeletal muscles


45/45

23-45

Effects of Aging

Vital capacity and maximum minute

ventilation decrease

Residual volume and dead space increase

Ability to remove mucus from respiratory

passageways decreases

Gas exchange across respiratory membrane

is reduced

ashish seminar

Documents