Three basic functions of the Larynx

• protect airway during swallowing
• intrathoracic pressure (coughing)
• sound production
• passive (respiration)

3 unpaired cartilages of larynx

• epiglottis
• thyroid
• cricoid

3 paired cartilages

of larynx

• arytenoids
• corniculates
• cuneiforms

Arytenoid Cartilage

• artenoid cartilages have vocal proccess and muscle process
• vocal process is anterior and attaches vocal ligaments

Thyrohyoid membrane

• goes from thyroid to hyoid
• has two thickened parts, medial thyrohyoid ligament and lateral thyrohyoid ligament
• has hole that allows passage of internal laryngeal nerve (sensory) and artery

Cricothyoid ligament

• runs from cricoid cartilage to thyroid cartilage
• has a thickened middle part called medial cricothyroid ligament

Vocal Folds

• vocal process forward to thyroid cartilage
• top edge of cricothyroid ligament on inside

Quadrangular Membrane

• tube that comes from the edge of teh arytenoid and wraps around to the epiglottis 
• tube with in the tube of the thyroid cartilage
• top is opening into larynx itself
• bottom edge is called vestibular ligament and sits right about the vocal ligaments

Ventricle of Larynx

• space between false (sup) and true (inf) vocal folds
• false vocal fold in vestibule of larynx
• sometimes called glottis? 
• so epiglottis is above it

Cricothyroid muscle

• from cricoid cartilage to thyroid cartilage
• rotates thyroid cartilage on top of cricoid cartilage
• has effect of stretching the vocal folds

Lateral Cricoarytenoid

• goes from cricoid to musclular process of arytenoid
• closes rema glottis ( space between vocal folds)

Posterior Cricoarytenoid

• from back posterior side of of cricoid to musclular proccess of arytenoid
• pivots arytenoid, opening up the rima glottis (space between vocal folds?

Transverse Arytenoids

and

Oblique Arytenoids

• goes from muscular process of one arytenoid to the other (transverse)
• muscular process of one to the apex of the other (oblique)
• both of these slide the arytenoids together, closing vocal folds

Thyroarytenoid muscle

• relaxes the folds by sliding them arytenoids forward
• provides substrate for vocalis muscle (thyroaretynoid muscle to folds themself)
• responsible for pitch(high and low)

Innervation of intrinsic laryngeal muscles

• superior laryngeal does cricothyroid
• recurrent laryngeal does all other motor
• sensation is divided between the 2 at the vocal folds

Vascular system of larynx

• superior laryngeal artery off superior thyroid artery(external carotid)
• inferior laryngeal artery off inferior thyroid artery(subclavian)

4 Steps of speech

• respiration (generation of energy)
• phonation (creation of sound)
• resonation (filtering and enhancing of sound)
• articulation (taking sound and turning into language)

Respiration

• energy production as you inhale/exhale
• normal respiration is about 1:1 inhale/exhale
• speach is about 1:8 inhale/exhale seconds
• controled by different parts of brain 
• rhythm and rate and neural control is different

Phonation

• sound production
• vocal fold vibration from exhaled air
• vibration of airwaves is sound (mechanoreceptor)
• pitch=frequency of vibrations
• males have deep voices because thyroid cartilage is bigger making vocal folds longer
• change w/ age (womens folds get longer)
• pathology (tissue level make up of folds)
• hoarsness is tissue around folds becomeing swallen
• damage to recurent laryngeal nerve would damage voice (left more often)
• thyroid surgery can also damage nerves

Resonation

• amplification and enhancement (inaudible to audible)
• makes voices unique
• adds energy and volume
• use sinuses, nasal and oral cavity, vestibule of larynx and pharynx
• also can use surfaces (opera and back pharyngeal wall)
• vibrations of solid matter and air within a cavity

Articulation

• anatomical articulators: change/modify airflow, create speech
• joining of two structures
• tongue, teeth, cheeks and soft palate working together, lips
• unvoiced sounds dont need vocal chord vibration

Bacterial Pnomonia

• caused by food getting into the airway
• common for really old and really young

Liquid Swallow

• done mostly by tongue 
• tongue works as pump
• eppiglottis covers larynx

Process model of swallowing

• stage I transport
• Processing
• Stage II transport
• Swallowing

Stage I Transport 

(swallowing)

• tongue carries food to molar region "pullback" mechanism
• tongue rotates to place food on the occlusal surfaces of lower teeth

Food Processing

• food particles: softened adn reduced in size
• chemical and physical processing
• jaws and tongue in constant motion
• food constantly repositioned
• tongue movt critical in mastication
• soft palate motion linked to jaw motion

Stage II Transport

(swallowing)

• food propelled into the oropharynx
• squeeze back mechanism
• processing continues
• tongue and jaw motions linked
• happens at same time as chewing
• bolus accumulates in the oropharynx and valleculae

Swallowing 

(solids)

• bolus propelled primarily by posterior thrust of tongue
• pharyngeal clearance-sequential contraction of constrictor muscles
• assisted by gravity
• requires opening of Upper Esophageal Sphincter

Traditional Model of Human

Swallowing

• spaces separate: seal btw oral cavity and oropharynx
• activities/stages separate: analyze each behavior independently
• food held in mouth until swallow onset

Disordered Oropharyngeal Swallowing

• difficulty initiating swallow (not enough sensory signal) (give up and airway opens)
• Nasopharyngeal regurgitation (soft palate doesnt block and liquid goes up nose)
• pulmonary aspiration
• residual is not moving all food out

Neurohypophysis

• pars nervosa and infundibular stalk, light staining
• resident cell is pituicyte, a support cell that expresses glial fibrillary acidic protein (GFAP) and associates with neuronal axons from hypothalmus
• Paraventriular nucleus (close to ventricule above supraoptic and most superior) produces oxytocin
• supraoptic nucleus (just above optic chiasm) produces ADH
• neural hormones stored in herring boddies

Oxytocin

• paraventricular nucleus of neurohypophysis
• promotes milk letdown from mammary gland by stimulating contraction of myoepithelial cells
• stimulates myometrial smooth muscle cells in the uterus to contract during parturition
• love/bonding connection

ADH

• also called vasopressin
• supraoptic nucleus
• increases water reabsorption by collecting ducts in kidney
• prootes contraction of vascular smooth muscles

Hypothalmo-hypophyseal portal system

• starts out at superior hypophyseal artery
• ends at hypophyseal veans
• between hypothalmus and adenohypothesis

Median Eminence

• arcuate or tuberal nucleus produce physiotropic hormones
• releasing or inhibiting hormones
• transported in portal system
• protein peptide hormones (bind to cell surface)

Acidophils

• in pars distalis
• somatotrophs (growth hormones) and lactotrophs (prolactin)

Basophils

• in pars distalis
• produce corticotrophs (adrenal cortex hormone), gonadotrophs(FSH and LH) and thyrotrophs (thyroid stimulating hormones)

Pineal Gland

• from epithalmus
• produces melatonin (sleep hormone)
• less light, more melatonin produced
• causes gonadotropin and Growth hormone and thyroid stimulating hormone might be inhibited by melatonin
• pinealocytes found in chords produce melatonin
• find accumulations of brain sand

Melatonin signliling pathway

• light sensitive cells in glanglion layer utilize photosensitve pigment melanopsin
• retinohypothalmic tract to cell odies of suprachiasmic nucleus of hypothalmus
• travel down spinal chord in hypothalmo-spinal tract
• synapse with sympathetic preganglionc in IML
• pre ganglionic axons to superior cervical ganglion
• post ganglion axon to pineal gland 

Thyroid gland cells

• parafollicular cells produce calcatonin
• folicular cells produce thyroid (T3 and T4) cells
• uses atp to move iodide into cell to make thyroid hormones, enzyme then gets rid of electron (makes iodine)
• thyroglobulin and tyrosine?