MIKE RES Flashcards
List of hyoid bones
Thyrohyoid bone Keratohyoid bone Epihyoid bone Stylohyoid bone Tympanohyoid cartilage Basihyoid bone
Hierarchy of words for larynx area
Cricoid Thyroid Arytenoid Hyoid Epiglottis
Cats Tripped At Happy Easter
List the four main cartilages
Epiglottis
Thyroid
Cricoid
Arytenoid
List the four main processes of the Arytenoid cartilage
Cuneiform proces
Corniculate process
Muscular process
Vocal Process
List the three articulations of the thyroid cartilage and explain movement
Cricothyroid
Cricoarytenoid
Thyrohyoid
List the 4 main ligaments of the larynx
Vestibular ligament
Vocal ligament
Cricothyroid ligament
Cricotracheal ligament
Name the 3 folds and ventricle of the larynx
Aryepiglottic fold
Vestibular fold
Lat.ventricle
vocal fold
List the 4 sections of the larynx
Aditus laryngis
Vestibule
Rima glottidis
Infraglottic cavity
List the three extrinsic muscles and what the overall fx is
Overall fx = deglutition
Thyrohyoid m
Hypoepiglottic m
Geniohyoid m
List the five intrinsic muscles
Adductors (close glottis) Cricothyroid Lateral cricoartenoid Transverse arytenoid Thyroarytenoid
Abductors (open glottis)
- Dorsal cricoarytenoid
Cricothyroid m
Intrinsic adductor
Ori- lat cricoid
Ins- lat thyroid
Fx- tenses vocal fold preventing abduction
Lateral cricoartenoid m
Intrinsic adductor
Ori- lat ros cricoid
Ins- muscular process arytenoid
Fx- ventral edge arytenoid = adduct vocal cords
Transverse arytehoid m
Intrinsic adductor
Ori + ins = strap over dorsally, arytenoid mus process to bus process
Fx= close/fine tunes
Thyroarytenoid m
Intrinsic adductor
Dog/horse = divided into ventricular (ros) and vocalis (caud)
Ori = epiglottis + thyroid (midline)
Dorsal cricoarytenoid m
Intrinsic abductors
Ori - on cricoid
Ins - muscular process of arytenoid
Which cranial nerve does innervation of the larynx come from and the two main branches
Vagus n. —> cranial laryngeal n and caudal laryngeal n (arises from recurrent laryngeal n).
Recurrent laryngeal pathway, left vs right
L = around the aortic arch, goes up ventral groove between trachea and oesophagus
R = around R subclavian a. Continues up the dorsalateral trachea
Roaring in horses
Left recurrent laryngeal hemiplegia
dorsal cricoarytenoid m. (Only abductor)
Surgery correction
Caudal laryngeal n. Fx
Motor innervation for all intrinsic mm except cricothyroid Lateral cricoartenoid m Transverse arytenoid m Thyroarytenoid m Dorsal cricoarytenoid m
Cranial laryngeal n. Fx
And branches
Internal Cranial Laryngeal n
sensory to mucosa
External canal laryngeal n
- motor to cricothyroid
Microanatomy of trachea
Mucosa ( epi= pseudostratified columnar ciliated + goblet cells) (lamina propria = loose, vascular connective tissue) (mucosa cilia elevator)
Submucosa (seromucous tracheal glands)
Musculo - cartilaginous
Adventitia
Two sectioning of larynx
Cervical
oesophagus Dorsal to trachea rostral 2/3 then on left side caudal 1/3
Thoracic
- Dorsal to cranial vena cava
- bifurcates dorsal to base heart level 4th - 6th intercostal space
Tracheal stx 3 parts
C shaped hyaline cartilage Open dorsal Annular ligaments (fibre-elastic) Trachealis m Dorsal aspect in gap of rings Smooth m Carnivores = external, herbivores = opposite Shaped different
Pleura Stx
Serous membrane
simple squamous
Thin lamina propria
Serous fluid/ exudate (fluid leaks out of blood vessels) = lubrication
Formation of the pleura including “pulmonary visceral pleura”
As lung grows out from principle bronchi it pulls pulmonary visceral pleura with it
List the three layers of the pleura
Pulmonary visceral pleura
Parietal pleura
Pleural space
Importance and fx of pleura cavity
Fx - make lungs + pulmonary visceral pleura stick
Achieved =
- Slight vacuum in pleural space
- Innate surface tension of fluid
Mediastinum definition
Contains everything in the thoracic cavity except
lungs, caudal vena cava, right phenric artery
Cranial mediastinum
Pre cardiac Tracheal Oesophagus Blood vessels Sympathetic trunk Vagus Recurrent laryngeal Phenric
Middle mediastinum
Cardiac region heart ❤️ (pericardium) Descending aorta Oesophagus Bifurcation of tracheal Vagus n. Phrenic n.
Caudal mediastinum
Post-cardiac
plica venae cava (Caudal vena cava, R phenric n.)
Mediastinal recess (accessory lobe-horses)
Pulmonary ‘ligament’ (pleural fold)
Costo-diaphragmatic recess
no lung
3 surfaces of the lung
Costal
Mediastinal
Diaphragmatic
3 borders of the lung
Dorsal
Ventral (with cardiac notch)
Basal
List lung lobes L and R
L = Cranial (cranial + caudal) R = Cranial, intermediate, caudal, accessory
Tracheal bronchus
Extra tracheal bronchus (pigs + ruminants) on the right
Horse called the primary bronchus
Cardiac notch
The heart pokes out
Hilus explained an list the things coming out
Anchors lungs to trachea and heart Contains principal bronchus Pulmonary vessels Bronchial vessels Lymphatic vessels and nodes Nerves
The two divisions of internal structure and the parts in it
Conducting = branching bronchi Respiratory = respiratory bronchioles down
1 bronchi principal
1.Mucosa
longitudinal fold, epi = pseudo, lamina propria = loose connective (lymphocytes, capillary)
2. Smooth muscle = (circular to spiral)
3. Submucosa = (sero-mucous bronchial glands, elastic fibres BV)
4. Fibroelastic/cartilage (cartilage plates —> less continuous, them trachea)
2 secondary bronchus
ciliated epithelium bronchial glands elastic fibres smooth muscle (circular) cartilage
3 secondary bronchus
smooth muscle is spiral, bronchial glands and cartilage
Bronchioles
But muscle v important in controlling resistance to air flow and distribution of air to alveoli
- Bronchioles small but many of them = largest cross-sectional area of airway
have smooth muscle (spiral) and mucous around
Terminal bronchioles
Usually Respiratory bronchioles
2 from each term. Bronchioles
Occasional alveoli
CLUB CELLS
Explain the levels of the trachea
Club cells
(Formerly ‘Clara cells’)
Replace goblet cells of respiratory bronchioles and onwards
Secrete = “lipoprotein surfactant”
List the alveoli cells
Pneumocyte
Endothelial cell
Capillary
Alveolar space
Explain Blood-gas barrier
Type 1 epithelial cells
Basement membrane
Endothelial cells of capillaries
Explain the 3 factors which the lung has to combat and the 3 adaptions they have
Alveoli = delicate
Exposed to air
Smooth muscles = control rate
So air is humidified, warmed and filtered
Superficial lymphatics
Lx = sub-pleural connective tissue
Deep lymphatics
Lx follows bronchial tree Follows bronchial tree Tracheal-bronchial Pulmonary Mediastinal Lymph nodes
Innervation of lungs
Vagus (parasympathetic) -broncho-constriction Sympathetic -broncho-dilation -vasoconstriction bronchial aa
Explain the two divisions of the blood system
Functional Oxygenation Relatively simple Pulmonary arteries and veins Provide nutrition to alveoli (O2)
Nutritional
Supply (pleura, stroma
List the phases of embryology larynx, trachea and lungs
Starts at pharyngeal region laryngotracheal groove in floor foregut Pseudo glandular Canaliculi - Repiratory bronchioles, air sacs, blood supply Terminal sac - epithelium differentiates type I and II Alveolar stage - alveoli
Explain the pump mechanism
Lung have elasticity which helps with contraction
Inspiration (expansion) based on thoracic wall and diaphragm
Thoracic cavity bounded by
first 2 ribs cranially Thoracic vertebrae dorsally Sternum ventrally Ribs laterally Diaphragm caudally IMPORTANT = a sealed cavity by costal and diaphragmatic pleura
Thoracic cage
Ribs, vertebrae and sternum
Thoracic inlet
Cranial end of thoracic cage Bound by 1st vertebrae 1st pair of ribs laterally Manubrium sterni ventrally
Thoracic outlet
Caudal extreme
Last thoracic vertebrae
Last pair of ribs + costal arch
Diploid cartilage
Movement of thorax during respiration, the two joints
Costo-vertebral joints
Sternal ribs have costa-sternal joints
Costs-vertebral joints, the two parts
- Articulation of the head
2 convex facets articulate 2 adjacent vertebral bodies
Rotatory or trochoid joint
Ligament of the head + inter capital ligament - Articulation of tubercle
tubercle projects caudally at junction of neck and body
Tubercle art
Costa-sternal joints
synovial joints
Costal cartilage inter-sternebral cartilages (equivalent to intervertebral disc)
Joint capsule thin except dorsal and ventral, joint is strengthened by “stero-costal radiate ligaments”
Costo-chondral joints
fibrous joints between rib and costal cartilage
Periosteum and perichondrim merge
Motion of the rib movement
- Mainly rotation around head-tubercle axis
- greater movement in caudal ribs than cranial
Intercostal muscles
External
Run up/forwards, drawing ribs cranially and laterally for inspiration
Internal
Muscle fibres run down/forwards
“Action controversial, possible involved in inspiration”
List 9 muscles that may assist with breathing
Scalenus Latissimus dorsi Longissimus thoracic Iliocostalsis Rectus thoracis Transverse thoracis Serratus dorsalis Serratus cranialis Serratus caudal
Thoracic wall blood vessels dorsal branch
This branch is divided into
spinal branch - spinal cord and its coverings
Dorsal cutaneous branch to dorsal skin
Thoracic wall blood vessels ventral branch
Runs down medial surface medial surface of internal intercostal muscles, immediately caudal to ribs
Gives off multiple branches of lat. cutaneous branches
Explain the anastomoses of dorsal intercostal artery
It anastomoses with the dorsal intercostal arteries
Thoracic wall nerves
Run with the blood vessels
Diaphragm attachements
Dorsal = near thoracolumbar junction Laterally = roughly along line of last rib Ventrally = near xiphisternum
Diaphragm structure
Tendinous centre surrounded by muscular periphery which radiate from centre Has three parts Lumbar Costal Sternal
Explain the lumbar part of the diaphragm
Lumbar part is wider, has two muscular crura attached to lumbar vertebral bodies
Right crus is larger than left (right extends past midlineover to left side)
Explain the costal part of the diaphragm
Attachment from 8-last rib
This part periphery interdigitates with transverse abdominal muscle
Explain the sternal part of the diaphragm
Attachment arises from dorsal surface of sternum just cranial to diploid cartilage
Where is the only place where pleura and peritoneum come together
Lumbocostal arch = between crura and attachment to last rib, passing over the posts muscles without attachment.
List the three hiatus in the diaphragm
- `Aortic
most dorsal
Contains (aorta, right azygos vein and cisterna chyli) - Oesophageal hiatus
located at the junction of right and tendinous centre
Contains (oesophagus, vagus nerve trunk and oesophageal vessels - Caval foramen
an opening in tendinous centre on the right side
Caudal vena cava
Diaphragm blood supply
Musculophrenic artery supplies muscular periphery A terminating branch of internal thoracic artery Cranial phrenic artes supplies crura Arises from thoracic aorta at aortic hiatus Phrenic-abdominal artery arising from abdominal aorta Also applies diaphragm
Phrenic nerves description
Motor and sensory to diaphragm
Arises from ventral branches of cervical nerves (5-7)
Untie just cranial to thoracic inlet to form left and right phrenic nerves
pass medial to subclavian arteries
At level of 1st rib L and R communicates with cervical-thoracic (stellate ganglion), via a communicating branch
`Phrenic nerves L vs R
Left stays in mediastinum and runs across surface of the heart
Right phrenic nerves leaves mediating to run with caudal vena cava in the plica vena cave
Phrenic nerve termination
Many branches on surface of diaphragm
Explain innervation of periphery of diaphragm
Also receives sensory fibres form last several intercostal nerve
Step of mechanics of breathing which decreases pressure
Volume change by ribs swinging forward with increases value laterally.
Astral ribs swing downwards which increases volume ventrally
Diaphragm contracts = caudal volume increases
Explain the negative pressure in the inter-pleural region normally
Inter pleural is always slightly negative
Explain tracheal collapse, difference between cough on expiration and inspiration
Common signalment = older small and toy breeds
Goose-honk cough
Cough on
Inspiration = collapse in cervical trachea
Expiration = collapse in thoracic trachea
Anatomical dead space
Air in tract which does not undergo gaseous exchange
- trade off = narrow airways which reduce dead space but increase resistance with narrow lumen
What happens at birth
Born, lungs filled with fluid Remove as much fluid asap Exaggerated respiratory movements open alveolar sacs A quick transition to air-filled lungs Need to make sure surfactant produced
Nose components
External nose
Nasal cavities
Paranasal sinuses
Bones of the nose
Nose and nasal cavity is supported by none and cartilage lined by mucous membrane
Supporting bones of the nose
Nasal, maxillary, incisive, frontal, lacrimal, zygomatic, ethmoid
Floor of the nasal cavity
Roof of oral caivty, formed by the bones
Incisive
Maxillary palatine process
Palatine
External nose
Species specific
Morphology= lateral nasal cartilages + type of skin round nose
Nose is supported by dorsal and ventral lateral nasal carriages
Sometimes an accessory cartilage present
Lateral nasal carriages
Are extensions of cartilaginous nasal septum
Dog, cat and goat nasal cartilage
Cartilages are complete laterally
Thick hairless skin (plenum nasale)
confined to area around nostrils
Well defined philtrum
Pig nose cartilage
Complete laterally
-extra medial supported by rostral bone
Plenum rostral is continuous with upper lip
Small philtrum
Ox external nose cartilage
Complete laterally
Plenum nasolabialis continuous with upper lip
No philtrum
Horse eternal nose cartilage
Lateral cartilages are small
Extra alar cartilages
supports dorsal, medial + ventral carriages
No cartilage support laterally allowing for great distension fo nostrils ( as obligate breathers)
Normal hairy skin around nostrils
Blind ending diverticulum
Gland present and not present in planum based on species
Present in ruminants and pigs
Absent in carnivores but lateral nasal glands, glands in septic and lachrymal glands have same fx in providing moisture for nose
Nasal septum role
Divides nasal cavity into left and right halves
Nasal septum consists of
- Perpendicular plate (caudally) (continuous with cribriform plate
- Cartilaginous nasal septum
Nasal conchae
Thin complies, bony scrolls projecting from lateral wall
There sections
dorsal (slightly curled)
Ventral (tightly folded series of scrolls)
Mucosal folds
Straight fold rostral extension of dorsal conchae Alar fold -rostal extension of ventral conchae - alar fold appears bulbous particular in dog (diverting air to increase evaporation)
Ethmoidal conchae (ethmoturbinates)
are series of folding plates (not scrolls)
Caudal part of nasal cavity
Associated with ethmoid bone
Cranial border = frontal sinus
What are the three meatuses
Dorsal and ventral conchae divide the cavity into 3 spaces called meatuses
Dorsal
Middle
Ventral
List four structures associated with nasal
Incisive duct
Vomero-nasal organ
Lateral nasal gland
Naso-lacrimal
Explain the incisive ducts
Aka naso-palatine
Paired ducts
Connect oral and nasal cavities
Nasal opening is in the ventral meatus at the level of canine tooth
Oral opening is on the incisive papillae just caudal to upper incisors
Explain horse incisive ducts
Duct does not open into oral cavity (ends blindly)
Explain the vomer-nasal organ
Aka organ of Jacobson
paired blind sacs that run caudal from incisive ducts and end at the level between 2nd and 4th cheek teeth
Supported by cartilage
Fx
epithelium of ducts has both respiratory and olfactory mucosa
Detect pheromones & ‘flehmen’ response
Associated with the relationship between taste and smell
Explain lateral nasal gland
produces serous fluid, is microscopic
Present in all species except ox
Near nasomaxillary opening, duct opens into middle meatus near end of straight fold
Fx
moistens inhaled air, may aid comer-nasal organ
In dogs = moistens nose and aids thermoregulation
Explain naso-lacrimal duct
runs from medial cantos of eye into nasal cavity
Opens into floor of nostril at the junction of skin and mucosa
Pigs (often dogs) have a second opening on lateral surface near the end of the ventral conchae)
drains eye to prevent weeping
Aids in moistening nose and nasal cavity
Often blocked in brachiocephalic breeds
Microanatomy of nasal cavity
There are two regions
Respiratory
Olfactory
Location of respiratory mucosa
paranasal sinuses
Part of dorsal and all ventral conchae
Lateral, dorsal, ventral nasal wall and part of the septum
Explain the respiratory mucosa histology layers
Epi- pseudostratified columnar, ciliated w goblet cells (same as trachea and bronchi)
Paranasal sinuses are more cuboidal to squamous epithelium with fevered glands and goblet cells
Laminar propria and submucosa
loose connective tissue, blends w periosteum or perichondrium
Contains simple branched tubuloacinar mixed nasal glands (less in sinuses)
Deeper layers contain erectile venous plexuses with smooth muscle sphincters
Olfactory mucosa Lx
Lines these structures Ethmoturbinates Parts of the dorsal conchae Part of the nasal septum vomeronasal organ
Olfactory mucosa 3 cell types of the epithelium
Sensory (olfactory) cells
bipolar neurons
Extend through entire height of epithelium
Long non-motile cilia
2. Sustentacular (supporting cells)
slender cells, many microvilli (no cilia)
3. Basal cells
- rough spherical, nuclei close to basement membrane
Olfactory mucosa laminar propria and submucosa
contains Bowman’s glands (mainly serous)
Moistens surface so odiferous molecules can dissolve
Flush surface of epithelium to remove odiferous substances
Deep layers contain deep erectile venous peruses and bundles of non-myelinated olfactory nerve fibres (film olfactorum)
Three functions of the nasal cavity
Olfaction macrosmatic = good animal smell Microsmatic = poor sense of smell (humans) Anosmia = no smell sense 2. Filtration of inspired air dust and bacteria are trapped in mucous layer Removed by ciliary action 3. Warming and humidifying air maintain a layer of moisture in alveoli Humidified air assist with olfaction Warm air holds more moisture Warming air= thermoregulation
Explain paranasal sinuses generally
are diverticulum of the nasal cavity that extend into surrounding bones
Continuous with naso cavity
Lined by mucoperiosteum
Originate in embryo continues to enlarge after birth as skull matures
List 6 possible fx of paranasal sinuses
Lighten skull Thermally insulate Protect eyes, nasal passages and cranial cavity Absorb shock to head Impart resonance to voice Increase area of olfactory membrane
Give general description of maxillary sinus
Largest, communicates with middle meatus via has-maxillary opening Species variation hard palate - palatine sinus Sphenoid bone - sphenoid sinus Medial aspect of orbit - lacrimal sinus Nasal conchae - conchal sinus
Frontal sinus
Opens into ethmoidal meatus of nasal cavity
- except in horse - opens into caudal maxillary sinus
Ethmoidal meatus
Narrow cavity located obliquely below the superior concha
List the four pairs of horse paranasal sinuses
Maxillary
Frontal (or conch-frontal)
Sphenopalatine
Ethmoidal
Explain paranasal maxillary sinuses
incomplete bony septum divides rostral and caudal parts
Drains -= middle meatus via nasomaxillary opening
Longitudinal plate of infraorbital canal divides it into lateral and medial
Important communication with cheek teeth
Explain paranasal frontal
-with dorsal conchal diverticula
drains = caudal maxillary sinus via frontomaxillary opening (not directly into nasal cavity)
Many incomplete bony septa in frontal sinus
Ox paranasal sinuses
6 pairs of sinuses Maxillary sinus with with diverticula palatine Lacrimal Sphenoid Conchal
Frontal sinuses
completely surround cranial cavity
Involves frontal, parietal, interparietal, part of temporal, occipital bones
Corneal diverticulum in adults (deworming adult cattle exposes mucoperiosteum of frontal sinus)
Explain pig paranasal sinuses
5 Pairs of paranasal sinuses Maxillary sinus with 3 diverticula Lacrimal Sphenoid Conchal Frontal sinus involves frontal and parietal bones Large (up to 5 cm deep) Difficult to stem pigs mechanically
Explain dog paranasal sinuses
Two basic Paris of sinuses
Maxillary
often called maxillary recess as communicates freely with nasal cavity
Carnassial tooth embedded in later wall of sinus
Frontal sinus = small and insignificant
Cat paranasal sinus
two basic pairs of sinus, similar to dog
Maxillary
0 can have sphenoid extension
P3 and P4 just under orbit therefore infection here can cause discharge and swelling in the eye
Frontal sinus
- blockage or infection of frontal sinus can be alleviated by flushing ethmoidal meatus via sinus
Explain the Nasopharynx
Air reaches here from the choanae(internal nares) to nasopharynx
chonanae are separated by vomer (dorsal to palatine bone)
Explain the Eustachian tubes
Nasopharynx is connect to middle ear via the auditory (Eustachian) tubes
supported by a cartilaginous trough open ventrally
Keeps middle ear at ambient pressure
In horse = ventrally to form large paired guttural pouches
Explain guttural pouches
paired, ventral invaginations of E tubes
Thin walled
Occupy space between base of cranium, atlas and pharynx
Lined with pseudostratificed columnar epithelium
Goblet cells present (mucous)
Guttural pouches sit over stylohhyoid bone which divides them into a small lateral and large medial portion
List blood vessel associated with guttural pouch walls
Blood vessels
external and internal carotid artiery
Maxillary artery and vein
Ventral cerebral and transverse facial veins
List nervous structures associated with guttural such walls
Facial CNVII IX X XI XII cranial cervical ganaglion
List gland structures associated with guttural such walls
Salivary glands - parotid and submandibular
Drainage of guttural pouches
Each pouch communicates w nasopharynx via the silt- like pharyngeal orifice of auditory tube opens into nasopharynx
slit supported by cartilage
Opens durning grazing and swallowing
Fluid can accumulate whne block or excessive secretion
Surgical access to guttural pouch
Via Viborg’s triangle
lingo facial vein
Ramus of mandible
Tendon of sternocephalic muscle
Guttural pouch possible fx
selective cooling of brain
Blood to brain internal carotid artery
Allow loose attachment to pharynx to increase swallowing efficiency in long necked animals
Cardio-respiratory evolution
Major changes in cardiovascular system have accompanied changes in respiratory system
Over time it has become more efficient with 4 chambers and seperate pulmonary and systemic circulation
Cardio-respiratory evolution in fish
Gas exchange in gills
Requires flow through mouth and over membranes to allow gas exchange
Fish have 1 capillary bed before return to heart
Mammals have 2 capillary beds before return to heart
Cardio-respiratory evolution from fish to land
Lobe-finned fish were first to have both gills and lungs
- lungs evolved from single ventral out-pouching of gut
- then due to stability problems with ventral position in water, the lungs migrated to a dorsal position
Swim bladder in fish
In modern boney, ray-finned fish is a homolog of lungs
Some swim bladders retain connection with gut via pneumatic duct (trachea homolog)
Lost in most advanced fish, gas regulated by red body
Cardio-respiratory evolution in amphibians
Can respire though any moist well-vascularised mucous membrane (mouth, skin, primitive lung)
Cardio-respiratory evolution in amniotes
Amniotes = (reptiles, birds, mammals)
Have a distinct, thorax and neck
lungs further from thorax
Evolution of conducting airway and separation of conducting and respiratory components
Cardio-respiratory evolution in birds and mammals
Developed completely separate pulmonary circulation, 4 chamber heart, on functional aortic arch
Cardio-respiratory evolution of reptile heart
Septum only partly divides ventricle
Vasculature still retains several aortic arch derivatives
Cardio-respiratory evolution of birds
different but very efficient system of pulmonary ventilation compared with mammals
System of air sacs
A flow through system
No gas exchange in air sacs
Air flows through lungs during both inspiration and expiration
Counter current blood flow system as air flows one way
(Very efficient at extracting O2)
