week 6: respiratory physiology: structure and function Flashcards
what is the respiraoty system
network of organs and tissues that helps us to breath
airways, lungs, blood vessels, respiratory muscles
collectively work toghether to move ox around body and remove waste products
functions of respiratory system (7)
-respiration
-speech and smell
-warms and humidifies atmospheric air to match body temp
-protects airways form harmful substances
-contributes to acid base balance in blood
-enhances venous return by respiratory pump
-activates certain plasma proteins as they pass through pulmonary circulation
respiratory function can be divided into
external respiration
internal (cellular) respiration
external respiration 4 components
- pulmonary ventilation
- gas exchange between lungs and blood
- O2 and CO2 transport in blood
- gas exchange: systematic tissues and blood
pulmonary ventilation
movement of air into and out of lungs
inspiration and expiration
occurs as a result of bulk flow
gas exchange betweens lung and blood occurs via
diffusion
what does internal (cellular) respiration involve
using O2 withing mitochondria to generate ATP by oxidative phosphorylation
inspiratory capacity
tidal vol+ inspiratory reserve vol
functional residual capacity
expiratory reserve vol+ residual volume
vital capacity
tidal vol+ inspiratory reserve + expiratory reserve
total lung capacity
vital capacity+ residual capacity
hyperpnea
an increase in ventilation to meet an increase in the metabolic demands of the body
dyspnoea
laboured or difficult breathing
apnoea
temporary cessation of breathing
tachypnoea
rapid, shallow breathing
hyperventilation
a condition in which ventilation exceeds the metabolic demands of the body
hypoventilation
a condition in which ventilation is insufficient to meet the metabolic demands of the body
hypoxia
a deficiency of oxygen in the tissues
hypoxemia
a deficiency of oxygen in the blood
hypercapnia
an excess of carbon dioxide in the blood
hypocapnia
a deficiency of carbon dioxide in the blood
extra-thoracic airways refer to airways
upper airways-outside of chest
intra-thoracic airways refers to airways
inside the chest
upper airways key function
warm, moisten and filters air as it travels through mouth and via naval passages
upper airways refers to air passages in
head and neck
conducting zone
functions to conduct air from larynx to lungs
upper airway, larynx, trachea, primary bronchi, secondary bronchi, tertiary bronchi, smaller bronchioles, bronchioles, terminal bronchioles
respiratory zone
site of gas exchnane
inner diameter as you move down conducting zone
decreases
reason for abudance of cartillage in larynx and trachea
upper airway needs high proportion of cartillage to prevent collapsing
bronchioles and terminal bronchioles and cartilage
do not contain any, makes them capable of collapsing,
therefore they contain elastic fibers to prevent
conducting zone lined with
epilthelium
function of epithelium of conducting zone
acts as protective barrier, secretes and absorbs substances
function of epithelium lining larynx and trachea (and bronchi to less extent)
contain goblet cells and ciliated cells
goblet cells
secrete mucus
coats airways and acts to trap foreign particles in inhaled air
ciliated cells
hair like projection of ciliated cells
beat together to propel mucus containing trapped particles towards glottis and pharynx- mucus escalator
prevents mucus build up in airways
build up of mucus in airways increases likelihood of
respiratory tract infection
as it promotes growth of bacteria
cilia are paralysed by
cigarette smoke
at levels below bronchi, foreign matter engulfed by
macrophages engulf
in interstitial space and surface of epithelium
wall of alveolus
single layer of epithelia cells - type 1 alveoli cells
overlying basement membrane
fused basement membrane between alveolar epithelial cells and endothelial cells of capillaries
in many places in lungs alveolar epithelial cells and endothelial cells of capillaries are so close together their basement membrane fuse together
respiratory membrane
capillary and alveolar walls form barrier
respiratory membrane function
separates air from blood
0.5micrometres thick- essential for efficient gas exchange
number of alveoli in human
3 million in a lung
100 square metre surface area
type 2 alveoli cells and alveolar macrophages
engulf foreign particles/ pathogens inhaled into lungs
dead macrophages are removed from alveolar
into conducting zone, swallowed with mucus
chest wall
composed of structures that act and work together to protect lung
ribcage, sternum, thoracic verterbrae, associated respiratory muscles and connective tissues
each lug surrounded by separate
plueral sac
pleura composed of
layer of epithelial cells and connective tissue
visceral pleura
pleural sac attached to lung tissue
parietal pleura
pleural sac attached to chest wall
between visceral and parietal pleura
intrapleural space
contains intrapleural fluid
diaphragm is
highly oxidative and fatigue resistant as it is always contracting and relaxing to support pulmonary ventilation
expiration during normal, tidal breathing is a
passive process
driven by elastic recoil of thoracic wall
when does expiration become an active process
increasing respiratory demands
