PC1000

anatomy - thoracic/respiratory

Bony thorax

bones and cartilage

thoracic wall

made up of muscles

thoracic cavity

mediastinum and 2 pleural cavities

pleural cavities

contains the lungs

central mediastinum

oriented longitudinally and contains the heart, oesophagus, trachea, plus major nerves and vessels

costal cartilage

made up of hyaline cartilage, attaches to the anterior part of the ribs to the sternum, allowing the thoracic cage to be flexible for movement - CPR

ribs

lateral

sternum

anterior and made up of 3 parts, manubrium, body, and xiphoid process, it joins the connects the ribs through costal cartilages forming the thoracic cage

12 thoracic vertebrae

posterior

how many ribs are there in total

24, 12 pairs

true ribs

1-7 ribs which are directly attached to the sternum through the costal cartilage

false ribs

8-12 which don’t directly connect to the sternum and allows the thorax to have the mobility necessary for respiration

floating ribs

11-12

vertebrae column

gives us our longitudinal axis, contains the spinal cavity thus protects and supports the spinal cord

how many vertebrae are there

33 vertebrae:

* 7 cervical
* 12 thoracic
* 5 lumbar
* 5 sacral fused
* 4 coccygeal fused

how are vertebrae separated

each vertebrae is separated from its neighbour by an intervertebral disc of cartilage which is supported by ligament and trunk muscles

discs

cushion of fibrocartilage and the principal joint between two vertebrae in the spinal column

cervical

neck, flexion and extension, lateral flexions, rotation C1 and C2

thoracic

chest, rotation only, other movements limited by almost vertical spinous processes and ribs

lumbar

back, flexion and extension, lateral flexion

sacral

pelvis, nil, fused

coccygeal

tail, small movement during childbirth and defecation

how many thoracic vertebrae are there

12

typical thoracic vertebrae

* inferiorly projecting spine
* large transverse processes
* costal demifacets
* body

inferiorly projecting spine

formed by the laminae which allows a degree of mobility that would otherwise not be possible due to the ribs

transverse processes

to support the articulation within the ribs

tubercle

used for attachment of ligaments to the vertebrae

subcostal groove

underneath each rib there is a subcostal groove containing the intercostal nerve, artery and vein

anterior end

attaches to the costal cartilage of that rib

posterior end

has a head, neck and tubercle

sternal angle

angle between the manubrium and the body at their joints, an important surface anatomy landmark used for physical examinations - to identify other anatomical points

muscles of respiration

* internal intercostal muscles
* accessory muscles
* external intercostals

internal intercostals

muscles for expiration, depresses and brings the ribs closer together

accessory muscles

any muscle that attaches to the ribs that could assist with respiration, eg. muscles of the trunk (adnominal muscles)

external intercostal

muscles for inspiration, elevates and spreads the ribs

diaphragm

for inspiration, primary muscle for respiration, flattens lowering the floor of thoracic cavity

rib movement during respiration

respiration movement, bucket handle movement, pump handle movement

respiration moment

increases the A-P diameter of the thoracic cavity - involves the upper 6 ribs

increases the transverse diameter of the thoracic cavity - lower 6 ribs

bucket handle movement

lower 6 ribs, elevation of lateral shaft of ribs

pump handle movement

upper 6 ribs, superior and anterior movements of sternum

A-P

antero-posteriorly, involves true ribs mainly, ribs elevate, sternum moves anteriorly

thoracic volume changes

* vertical
* anteroposterior
* transverse

vertical

flattening of the diaphragm

anteroposterior

sternum moves anteriorly and forward

transverse

mediolateral, low rib cages moves laterally

non-respiratory movements

* cough
* sneeze
* yawn
* sigh

primary curvatures

present in foetus life as part of the foetus’ original C-shaped vertical column T2 to T12

lumbar curvature

as the child begins to walk the lumbar curvature develops T12 to T15

secondary curvatures

develop after the foetal period which is critical to be able to walk upright as it balances and gives support

cervical curvature

C2 to T2 develops as an infant begins to lift the head and crawl

inspiration

both the diaphragm and external intercostal muscles contracts and further increases the size of the thoracic cavity

allows air to flow into the lungs

expiration

passive process that requires no muscle contraction

involves gases leaving the lungs

congenital

deformities present at birth

neuromuscular

abnormalities or trauma to the nerves and muscles around the vertebral column

idiopathic

unknown cause

structural divisions of airways

* upper respiratory tract (nose to larynx)
* lower respiratory tract (trachea to alveoli)

function divisions of airways

* conducting zone
* nose to bronchioles
* respiratory zone (alveoli)

nose

the start of the respiratory tract, hyaline cartilage forms the end of the nose and nostrils

nasa hairs

capture dirt and debris

nasal cavity

* provides airways for respiration
* houses the effectory receptors
* filters and cleans inspired air
* moistens and warms entering air
* contains conchae

conchae

protrudes from each lateral wall of the nasal cavity, they increase the mucosal surface area to slow down the movement of air

covered in mucus membrane to warm and humidify air

mucus

secreted by the respiratory epithelium that lines most of the cavity

production of mucous

pseudo stratified ciliated columnar epithelium with goblet cells produce mucus and water to trap particles and humidify air

paranasal sinuses

* spaces located within the skull
* decreases weight of the skull
* resonance to voicee
* al connect to the nasal cavity

pharynx

connection between nasal cavity, mouth to the larynx and the oesophagus inferiorly

components of pharynx

long muscular tubular structure which can be divided into 3:

* nasopharynx
* oropharynx
* laryngopharynx

nasopharynx

posterior to nasal cavity and superior to soft palate

soft palate

lies able the point where food enters the body should serve as an airway passage only - separates the mouth and nose

larynx

* voice production
* located at the top of trachea
* helps route air and food to the correct location via epiglottis
* protects the airways beneath it
* provides an open airway for breathing

abbucted

together

abducted

apart

nose and cavity

encased by cranial and facial bones

pharynx

throat

larynx location

anterior neck, lies anterior to the oesophagus, keeps food and liquid out of the respiratory tract

lined with stratified squamous nonketanized epithelium which prevents larynx surface from abrasions due to contact with food

trachea

mediastinum

upper respiratory tract

passageways from nasal cavity to the lungs

lower

passageways from trachea to alveoli

alveoli

air sacs where gases are exchanged

trachea

* open tube (patent)
* kept open by hyaline cartilage rings - C-shaped

oesophagus

lies posteriorly to the tranchea

mucosa

consists of a respiratory epithelium, secretes mucous and has cilia

Corina

point in which the trachea ends

tracheal wall

made of respiratory mucosa - goblet cells containing ciliated pseudsotratified columnar epithelia

outermost layer of trachea

outermost layer is a connective tissue reinforced by 16-20 rings of hyaline cartilage which helps keep airways open

not-complete rings on the outermost layer of trachea

open posteriorly, connected by smooth muscle fibres called tracheal muscle which helps force air upwards from lungs

mucous glands

secretes mucous containing enzymes - each day glands secrete about a litre of mucous containing lysosome

lysosome

after mucous traps dirt and bacteria, lysosome attached and destroys bacterial chemically

bronchial tree

* starts at the left and right go the primary bronchus
* bronchus tree ends at the terminal
* as the airways/respiratory tract divide they get smaller

bronchulus

smallest component and they have no cartilage

left bronchus

angular, longer and narrower

right bronchus

shorter, wides and more vertical

respiratory zone

* starts at the respiratory bronchioles
* branch into alveolar ducts and terminate at the alveoli sacs
* no cartilage and no smooth muscles

type I alveolar cells

* simple squamous epithelial cells
* forms a continuous lining of alveolar cells
* exceedingly thin, which permits rapid diffusion of gases across their plasma membranes

type II

* rounded epithelial cells secrete alveolar fluid called surfactant
* surfaced owers surface tension of alveolar fluid and prevents them from collapsing

respiratory membrane

* capillary wall + alveoli wall + basement membranes

walls of alveoli

squamous epithelia - very thin

external walls of alveoli

covered with pulmonary capillaries

pulmonary delivery of drugs

drugs can be administered through the lungs

* local treatment (respiratory diseases)
* systematic treatment

function of respiratory membrane

provides large surface area for rapid absorption rate from the blood stream

pleura

* thin, double layered