Respiratory system Flashcards
what are the functions of the respiratory system?
-gas exchange-intake of O2 and removal of CO2
-regulates blood pH
-smell
-filters inspired air
-vocal sounds (phonation)
-excretes small amounts of water and heat
what houses the lungs?
the thorax
what are the respiratory system structural zones?
-upper respiratory tract
-lower respiratory tract
what does th upper respiratory tract consist of?
-nose
-pharynx
what does the lower respiratory tract consist of?
-larynx
-trachea
-bronchi
-lungs
what are the respiratory system functional zones?
-conducting zone
-respiratory zone
what does the conducting zone do?
-it is involved with brining air to the site of external respiration and consists of the nose, pharynx,larynx,trachea,bronchi and bronchioles and terminal bronchioles
what does the respiratory zone do?
-it is the main site of gas exchange and consists of the respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli
where does air passing through the respiratory tract transverse?
-nasal cavity
-pharynx
-trachea
-primary (1) bronchi
-secondar (2) bronchi
-tertiary (3*) bronchi
bronchioles
-alveoli (150million/lungs)
how is the nasal cavity?
-it has an external nose that is visible on the face
-has an internal nose with is a large cavity beyond the nasal vestibule
how is the nasal cavity divided?
-it is divided ny the nasal septum into right and left nares
what is the pharynx?
- a hollow tube that starts posterior to the internal nares and descends to the opening of the larynx in the neck
how is the pharynx formed?
by a complex arrangement of skeletal muscles that assist in deglutition
what are the functions of the pharynx?
it acts as:
-passageway
-resonating chamber
-housing for tonsils
what’s the larynx?
-the voice box
-it is composed of 9 pieces of cartilage and forms a short passageway connecting the laryngopharynx with the trachea
what is the trachea?
-a semi-rigid pipe made of semi circular cartilaginous rings
-it is 12cm long and extends from the inferior portion of the larynx
where is the trachea located?
anterior to the oesophagus
how is the trachea divided?
it is divided into right and left primary bronchi
what are the 4 layers the trachea is composed of?
-one layer of mucous secreting epithelium,the mucosa
-three layers of CT (submucosa, hyaline,cartialge and adventitia)
what does the respiratory tract cilia in the upper respiratory tract do?
-move mucous and trapped particles down toward the pharynx
what does the respiratory tract cilia in the lower respiratory tract do?
-moves mucous and trapped particles up toward the larynx
what changes happen to the bronchial tree?
changes that cause all the branches from the trachea to the terminal bronchioles conduct airways and do not participate in gas exchange
what do respiratory bronchioles do?
-give way to alveolar ducts and the epithelial (simple cuboidal) changes to simple squamous which comprises the alveolar ducts, alveolar sacs and alveoli
-they also mark the start of the respiratory zone
how is the pulmonary lobule?
each pulmonary lobule is wrapped in elastic connective tissue and contains a lymphatic vessel, an arteriole,a venue and a terminal bronchiole
what are alveoli?
-cup shaped out pouching which participate in gas exchange
-they have alveolar macrophages
-there are fibroblasts which are reticular/elastic fibres
-the alveolar sac comprises two or more alveoli that share a common opening
what do alveolar macrophages do?
remove dust
what is a type 1 alveoli cell?
-it is a simple squamous epithelial cell
-it is the site of gas exchange
what is a type 2 alveoli cell?
-it is a cuboidal epithelial cell
-it has microvilli
-it secretes surfactant
-it decrease surface tension
pneumothorax
air
hemothorax
blood/pus
how do the lungs receive blood supply?
via two sets of arteries:
-pulmonary arteries
-bronchial arteries
what do the pulmonary arteries do?
carry deoxygenated blood from the right heart to the lungs for oxygenation
what do the bronchial arteries do?
-branch from the aorta and deliver oxygenated blood to the lungs primarily perfusing the muscular walls of the bronchi and bronchioles
what is ventilation-perfusion coupling?
the relationship between the air reaching the alveoli (ventilation) and the blood flow (perfusion) in the lungs
why is ventilation-perfusion coupling important?
-blood flow to each area of the lungs matches the extent of airflow to the alveoli in that area
what does vasoconstriction in the lungs in response to hypoxia do?
directs pulmonary blood from poorly ventilated areas of the lungs to well ventilated regions
what does hypoxia cause in all other body tissues but the lungs?
-causes dilation of blood vessels to increase blood flow
what can disruptions in ventilation-perfusion coupling lead to?
-conditions like hypoxia (low oxygen)
what are the three main steps of the process of gas exchange?
-pulmonary ventilation-breathing
-external pulmonary respiration
-internal tissue respiration
what happens in pulmonary ventilation-breathing?
-involves the movement of air between the atmosphere and the alveoli and consist of inhalation and exhalation
-changes to intathoracic volume allow ventilation to take place
what does the rate of airflow and effort required for pulmonary ventilation depend on?
-alveolar surface tension
-compliance of the lungs
-airway resistance
what happens in external (pulmonary) ventilation?
-gas is exchanged between the alveoli and the blood
what happens in internal (tissue) respiration?
gas is exchanged between the systemic capillaries and the tissues of the body
what does the rate of pulmonary and systemic gas exchange depend on?
-Partial pressure difference of the gases- link to altitude sickness
-Surface area available for gas exchange-link to emphysema
-Diffusion distance-link to pulmonary oedema
-Molecular weight and solubility of gases
what is oxygenated Hb called?
-oxyhaemoglobin
what is the most important gator that determines how much O2 binds to haemoglobin?
-the PO2, the higher the PO2 the more O2 combines with Hb
what happens with oxygen transport in the blood?
in the blood
-some O2 is dissolved in the plasma as a gas (about 1.5%,which is not enough to stay alive)
-most O2 (about 98.5%) is carried attached to haemoglobin (Hb)
what are the three different forms that CO2 is transported in, in the blood?
-7% is dissolved in the plasma as a gas
-70% is converted into carbonic acid by carbonic anhydrase (CA) before dissociating into bicarbonate and protons
-23% is attached to Hb forming carbaminohaemoglobin (Hb-CO2) but not at the same binding sites as oxygen
what is the equation that shows how CO2 dissociates into bicarbonate and protons?
CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-
what does Boyle’s law explain?
-the volume-pressure relationship
-it states that the pressure of a gas in a closed container is inversely proportional to the volume of the container
how is the respiration controlled?
-some stimulus disrupts homeostasis by increasing the arterial blood Pco2 pr decreasing pH or Po2
-the receptors input nerve impulses to the control centre
-there is then an output of nerve impulses to the effectors
-there is then a decrease in arterial blood Pco2,increase in pH and increase in Po2
-there is then a return to homeostasis when the response brings arterial blood Pco2,pH and Po2 back to normal
what is the control centre for the control of respiration?
-it is the inspiratory area in the medulla oblongata
what is the effectors in the control of respiration?
-muscles of inhalation and exhalation which contract are forcefully and frequently (hyperventilation)
what are the receptors in the control of respiration?
-central chemoreceptors in the medulla
-peripheral chemoreceptors in the aortic and carotid bodies
