Lecture 5: Respiration Flashcards
(29 cards)
What is Respiration?
The process of exchanging gases:
ventilation
external respiration
transport of gases
internal respiration
cellular respiration
what are the two divisions of the respiratory system
Upper Respiratory tract: filters, warms and humidified air
nose
nasal cavity
sinuses
pharynx
Lower Respiratory tract:
Larynx
Trachea
Bronchial Tree
Lungs
The Nose and Nasal cavity
The hollow space behind the hard palate and cribiform plates
Separated by the nasal septum
lined with mucous membrane (with pseudostratified ciliated epithelium)
air is warmed, moistened and filtered
Paranasal Sinuses
The sinuses are air filled spaces in the maxillary, frontal, ethmoid and sphenoid bones of the skull
Mucous membrane lining is continuous with the lining of the nasal cavity
The sinuses reduce the weight of the skull and serve as voice resonant chambers
Pharynx
The pharynx is posterior to the oral cavity and between the nasal cavity and the larynx:
NasoPHARYNX
OroPHARYNX
LaryngoPHARYNX
Larynx
Larynx is an enlargement in the airway superior to the trachea and inferior pharynx
It is composed of a framework of muscles and cartilages bound by elastic tissue
Larynx is made up of:
Three single cartilages:- Thyroid, cricoid and Epiglottic
Three paired cartilages:- Arytenoid, Corniculate and Cuneiform
What happens during swallowing in regards to the Larynx
The Larynx will elevate causing the epiglottis to move down and form a lid over the glottis, closing it off
The glottis
The glottis consists of a pair of folds of mucous membrane called:
true vocal cords (vocal folds)
space between them is called rima glottidis
THE VOCAL FOLDS ARE THE PRINCIPLE STRUCTURE OF VOICE PRODUCTION
Voice Production…
1) Laryngeal muscles attach to both the rigid cartilages and the vocal folds
2) Contracting and relaxing the muscles varies tension in the vocal cords
3) Air passing through the larynx vibrates the folds and produce sound - phonation, by setting up sound waves in the pharynx, nose and mouth
4) THE VARIATION IN THE PITCH OF THE SOUND IS RELATED TO THE DIAMETER, LENTGH AND TENSION IN THE VOCAL FOLDS
5) The greater the pressure of air, the louder the sound produces by the vibrating vocal folds
In a patient with Laryngitis what can we see:
Edema/ swelling
hoarseness of voice
Trachea
The Trachea is a flexible cylindrical tube
As it extends downward anterior to the oesophagus and into the thoracic cavity, it splits into the right and left primary bronchi
Left side has 3 lobes
Right side has 2 lobes
Lines with ciliated mucous membrane
wall has C shaped rings of hyaline cartilage to keep the trachea open
Bronchial Tree
bronchial tree consists of branches airways leading from the trachea to the microscopic air sacs in the lungs
Esch primary bronchus leads from the treachea to enter a lung
airway branching
conducting zone: where air is passed through
Respiratory zone : where rerspiration occurs
Development
develops from ventral aspect of Anferior Foregut Endoderm
1)Embryonic- rudimentary lungs, formation of major airways and pleura
2) Pseudoglandular - bronchia tree
3) Canalicular - Dista; airways, branching complete, first air blood barrier, appearance of surfactant, detectable acini
4) Saccular - expansion of air spaces
5)Alveolar - Alveolarization, Microvascular maturation
structure of the alveoli
As the bronchi continue to branch, they become narrower:
The amount of cartilage decreases until it disappears in the bronchioles
The smooth muscle becomes more prominent, then begins to diminish from bronchioles to alveoli
These respiratory tubes become thinner and thinner and the cell layers thin AND change until the alveoli are reached
- Alveolar wall is composed of simple squamous epithelium
Gas Exchange
The alveoli are the sites of the vital process of gas exchange between the air and the blood
Two Types of cells
type 1: Simple squamous epithelium
Type 2: Special cells that secrete surfactant
Gas exchange between alveolar air and the blood occurs through the respiratory membrane
alevolar wall - simple squamous epithelium
blood capillary wall - simple swuamous epithelium
Basement membrane - between alveolus and capillary
gas diffuses from areas of high partial pressure to areas of low partial pressures
Oxygen Transport
98% of oxygen is transported by the protein hemoglobin in the form of oxyhemoglobin
and
2% is dissolved in the blood plasma
factors which increase the release of o2 from hemaglobin are#:
decrease inPO2
Increase inpco2
increase in acidity
increase in temperature
When O2 is released it moves from blood into tissues
- about 75% of the o2 remains bound to hemaglobin in the venous blood ensuring safe co2 levels and thereby pH
Carbon Dioxide Transport
Blood flowing through the capillaries gains co2 because the tissues have a high pco2
The co2 is transported to the lungs in one of three forms
as co2 dissolved in plasma
as part of a compound with hemaglobin
as part of a bicarbonate ion - most is transported this way
Lungs
The right and left lungs are soft, spongy, cone shaped organs in the thoracic cavity separated by mediastinum
The right lung has three lobes and the left has three lobes
surrounded by Pleura:
Visceral
Parietal
Breathing Mechanisms
Breathing or ventilation is the movement of air from outside of the body into the bronchial tree and the alveoli
The actions responsible for these air movements are inspiration ( inhalation) and expiration (exhalation)
Pleural Fluid
Lubricating fluid secreted by the membranes
This reduces friction between the membranes, allowing them to slide easily over one another during breathing
Pleural fluid also causes the two membranes to adhere to one another
- a phenomenon called surface tension
Separates pleural cavities surround the left and right lungs
Boyles law
The volume of a gas varies inversely with its pressure
Muscles of Respiration
External intercostal
Sternocleidomastoid
Diaphragm
Respiratory cycle
One sequence of inspiration and expiration
