10: Respiratory system Flashcards
The function of the respiratory system
supply body with oxygen and to rid co2
Pulmonary ventilation
movement of air into and out of the lungs
external respiration
exchange of O2 and CO2 between air within the lings and blood
Transport of respiratory gases
via blood stream
Internal respiration
exchange of O2 and CO2 between blood and tissues (ISF)
Other integral roles of the respiratory system include;
- Speech/vocalisation
- Olfactory sense facilitation
- Control pH of body fluids via co2 removal
- Creation of pressure gradients that promote the flow of venous blood and lymph
- Help expel abdominopelvic urination, defecation and childbirth via breath holding.
Structure and function of the upper respiratory system
clean, humidify and warm incoming air, reabsorb heat and water from out going air.
Structure and function of the lower respiratory system
conducts air to the gas exchange surface (trachea and bronchi also help to clean, warm and humidify incoming air), gas exchange.
The function of the conducting zone
passageway that conducts, cleanses, humidifies and warms incoming air and reabsorb heat and water from outgoing air.
The function of the respiratory zone
where gaseous exchange occurs. Includes bronchioles, alveola ducts and alveoli.
Structures of the respiratory zone (upper respiratory system)
the nose or nostrils, nasal cavity, mouth, throat (pharynx), and voice box (larynx)
Structures of the conducting zone (lower respiratory system)
the passageway that conducts, cleanses, humidifies and warms incoming air and reabsorb heat and water from the outgoing air.
The nose summary
- only external structure
- beginning of the system
nostrils
nares
Nasal cavity contains
hair
mucosal epithelium lining
olfactory epithelium
sensory nerve endings- trigger sneeze to prevent irritants from getting to lungs
Mucosal epithelium purpose?
- around 1-1.5L/day is produced
- traps particles
humidified incoming air
contains antibacterial agents such as lysomes and definsins
Cilia structure and function
small hairs that move contaminated mucociliary to throat
mucociliary escalator
cilia and mucous
- moves contaiminated mucus up the throat-> stomach
protects respiratory zine from infection.
What stops cilia from working well?
age
cold temps (hence colds in winter)
damage from smoking (hence smokers cough)
nasal conchae structure and function
called a nasal turbinate or turbinal, is a long, narrow, curved shelf of bone that protrudes into the breathing passage of the nose in humans and various animals
- increases surface area of mucosal and creates turbulence so particles hit the walls and get stuck to the mucus.
Pharynx structure and function
aka the throat
- for both food and air
- shaped like a funnel that connects mouth to larynx
- Passageway for air (nasal cavity to larynx) and food (oral cavity to oesophagus)
- Contains lymphoid tissue (tonsils) which help to protect against pathogens
3 regions of the pharynx
1- nasopharynx (air only)
2- oraopharynx (dual)
3- laryngopharanyx (dual but begins to diverge)
Larynx structure and function
Structure= cartilage Function= - provide an open air wat to the trachea - separate food and air - facilitates voice production (holds vocal cords that are mucosal covered elastic fibers that vibrate when air rushes out of lungs to produce sound.) - includes the mucociliary escalator
Trachea structure and function
aka windpipe
connects the larynx to main bronchioles
structure= highly elastic, lined with ciliated mucociliary membrane, smooth muscle can constrict when we need to cough.
Function= mucociliary escalator, cartilage rings keep it from closing
approx 15-20 rings
Lungs and conducting zone structure and function
- Cone shaped
- elastic organs
- Apex= smallest tip. Lies deep to the clavicle
- Concave base= lies in superior to diaphragm
- Apex of heart lies to the left of the mid line
- Each lung is suspended in its own plural cavity, separated by plural membrane that compartmentalises the parts of the lung.
- Advantageous if one is infected/impacted the others can still able to function normally.
Parietal pleura structure and function
- Lines outside of lung separating it from thoracic wall.
- Continuous membrane that turns into visceral pleura when on lungs surface
Plural space structure and function
- Holds pleural fluid
- Acts at lubricant so that visceral and parietal and plural can slide along one another.
- Clings lungs to the thoracic wall
How many lobes are on each lung
Left: 2 (superior and inferior)
Right: 3 (superior, middle and inferior)
Lobes of the lungs structure
- Each lobe is functionally independent
- Each lobe is further divided into segments via connective tissue
- Each segment is served by;
o own artery
o own vein
o own airway (segmental bronchus)
Bronchi subdivisions
- divide into right and left primary bronchi
- branch up to 23 times to form bronchial tree of 2400km of airways
i. Primary bronchi
ii. Bronchi (that supply each lobe)
iii. Tertiary bronchi (divide repeatedly)
iv. Bronchioles= diameter <1mm
v. Terminal bronchioles= diameter <0.5mm
vi. Respiratory bronchioles= diameter <0.5mm
Respiratory zone
- where gas exchange occurs
Alveoli structure/components and function
Structure= thin-walled, expandable sacs
Function= site of gaseous exchange
Connected via pores
-
The function of alveoli pores
Pores= small holes that allow air pressure through lungs to be equalised + another rote for air to travel to other alveloi whos bronchi may have collapsed.
- similar to the artery circle in the brain, is helps avoid major damage and allows for function when injury occurs.
Alveoli macrophages
macrophages= provide as defense against any particles that manage to evade the cleansing processes of the upper respiratory ways
Two types of epithelial cells in the membrane
- Walls= made of type 1 epithelial cells for the respiratory membrane where they contact capillaries.
- Type 2 epithelial cells= scattered in alveoli and secrete fluid containing surfactant- detergent-like substance that coats alveoli surface, helping to keep them open.
Respiratory membrane structure and function
Function= Site of gas exchange via simple diffusion.
Structure= Thin air-blood barrier (0.5 nanometre wide)
- Thinness facilitates efficient gas exchange in conjunction with large surface area
- Respiratory membrane coated with fluid containing surfactant to;
o prevent delicate membrane from drying out
o acts to facilitate gas exchange.
Compose of
- single alveolar epithelial cell (types 1 cell)
- basement membrane
- Pulmonary capillary endothelial cell
Surfactant=
A fluid secreted by the cells of the alveoli (the tiny air sacs in the lungs) that serves to reduce the surface tension of pulmonary fluids; surfactant contributes to the elastic properties of pulmonary tissue, preventing the alveoli from collapsing.
2 ways blood is supplied to the lungs
- Pulmonary circulation
2. Bronchial circulation
Describe pulmonary ventilation
- Pulmonary arteries deliver deoxygenated blood to lungs
- Provide nutrients to alveoli (e.g. glucose)
pulmonary circulation: provides blood w/ nutrients to alveoli
Bronchial circulation
- Rise from aorta to provide oxygenated systemic blood to all lung tissue (except alveoli)
Bronchial circulation: all lung tissue except alveoli