respiration Flashcards
peak flow
a person’s maximum speed of expiration measured with a peak flow meter
tidal volume
the amount of air which enters the lungs during normal inhalation at rest
average tidal vol
500ml
vital capacity
the greatest volume of air that can be expelled from the lungs after taking the deepest breath possible
ventilation rate
the amount of air inhaled in a specific time period
VO2 max
the maximum or optimum rate at which the heart, lungs and muscles can effectively use oxygen during exercise, used as a way of measuring a person’s individual aerobic capacity
O2 dissociation curve
a curved determined by plotting on a graph the partial pressure of oxygen in the blood as the abscissa and the percentage of haemoglobin combined with oxygen in the form of oxyhemglobins as the ordinate
bohr shift
haemoglobin oxygen binding affinity is inversely related to acidity and to the conc of carbon dioxide
typical vent rate
12-20 breaths per minute at rest
vital capacity
adults 3-4 litres
inhalation mechanics
when we inhale the intercostal and diaphragm contract to expand the chest cavity. The diaphragm flattens and moves downwards and the intercostal muscles move the rib cage up and out.
This increase in size decreases the internal air pressure and so air from outside rushes into the lungs to equalise the pressures
exhalation mechanics
diaphragm and intercostal muscle relax and return to their resting positions. This reduces the size of the thoracic cavity, thereby increasing the pressure and forcing air out of the lungs
cell resp formula
C6H12O6 + 6O2 –> 6CO2 + 6H2O + ATP
Gas exchange occurs in the
alveoli
oxygen is carried by the ….. to the body tissue
blod
specialised structures of the alveoli
- walls are thin
- large surface area to vol ratio
- fluid lined enabling gases to dissolve
- many capillaries
- blood in capillaries do not flow too quickly yo allow maximum diffusion of gases
blood shunting
a pulmonary shunt is a physiological condition which results when the alveoli of the lungs are perfused with blood as normal, but ventilation fails to supply the perfused region. Ventilation/ perfusion ratio is zero
ventilation/ perfusion ratio
ratio of air reaching alveoli to blood perfusing them
blood perfusion
the process of a body delivering blood to a capillary bed in its biological tissue
hypoxic pulmonary vasoconstriction
pulmonary arteries constrict in the presence of hypoxia , without hypercapnia blood flow is redirected to alveoli with a higher oxygen content c
constriction and hypoxic pulmonary vasoconstriction
constriction leads to redistribution of blood flow to better ventilated areas of the lung, which increases the total area involved in gaseous exchange
what does hypoxic pulmonary vasoconstriction improve
ventilation/perfusion ratio and artery oxygenation- less helpful with long term- whole body hypoxia
what is the process of red blood cell production called
erythropoiesis
how long do stem cells take to become mature erythrocytes
7 days
mature erythrocytes live in blood circulation for about
100-120 days
erythropoietin
a hormone produced by the kidneys in response to hypoxia, which stimulates erythropoiesis
erythrocytes differentiate from
erythrotopietic bone marrow cells (hemopoeitic stem cell) found in red bone marrow
liver is the main site of
RBC production
what causes erythropoietin to be released
hypoxia
following eryptosis
haemoglobin content of cell is broken down and recirculated throughout the body
-broken down into iron ions and a green bile pigment, bilirubin which is released into the plasma and recicurculated to the liver, then bound to albumin and stored in gallbladder (bile)
bilirubin
a green bile pigment
haematopoietic stem cells
found in bone marrow of adults forming blood cells
diff between haemotopoietic stem cells and progenitor stem cells
progenitor cells can only divide qa number of time
EPO is released by the kidneys in response to
hypoxia- not enough oxygen in blood suggesting that new red blood cells have to be produced to cater for oxygen supply from the air
therefore when EPO is released hematopoietic and progenitor cells are stimulated to mature into RBCs
short term production of red blood cells is controlled by
EPO
hypercapnia
CO2 retention, elevated CO@ levels in the blood
Hypocapnia
a state of reduced CO2 in the blood–> usually results from deep or rapid breathing (hyperventilation
when there is reduced levels of CO2 in the blood, the body reacts by
increasing tidal volume and ventilation rate-> to inhale more oxygen
when there is reduced haemoglobin the body responds by
increasing tidal volume and ventilation rate
-due to haemoglobin needing to be as saturated as possible
adaptations of the respiratory system at high altitude
- additinal red blood ells asn capillaries are produced to carry more oxygen and CO2 due to EPO secretion by the kidneys
- lungs increase in size to facilitate the osmosis of O2 and Co2
- increase in vascular network of muscles which enhances the transfer of gases
breathing rate regulation
controlled by the medulla oblongata
inspiration occurs due to
increased firing of inspiratory nerves and so increases recruitment of motor until within the intercostals and diaphragm
exhalation occurs due to
a sudden stoop in impulses along the inspiration nerves
breathing rate is controlled by
chemoreceptors in the main arteries measuring levels of oxygen and CO2
increased H+ conc in the blood (due to too much CO2)
increases ventilation rate (also occurs when lactic acid is produced during exercise)
tissues and their cells in the trachea
cartilage tracheal muscle mucosa- cili and goblet cells submucosa- seromucous glands blood vessels to warm cold air
tissues and their cells in the bronchi
ciliated columnar cells smooth muscle controls air flow tertiary have less cartilage very few goblet cells folded epithelium
tissues and their cells in the bronchioles
no goblet cells no cartilage no glands smooth muscle some Clara cells Citrated cuboidal epithelium
tissues and their cells in the
95% type 1 oncocytes 5% type 2 thin basement membrane Pores of Kohn Macrophages surfactant
pore of Kohn
holes in walls of adjacent alveoli
Clara cells
dome shaped cells with short microvilli, found in small airway of he lungs–> found in the ciliated simple epithelium
ciliated epithelium contain
Ciliated epithelium contains goblet cells, which secrete mucous.
carina
ridge where the trachea separates into bronchi
tracheal bifurication
ridge of cartilage in the trachea (carina) that occurs between the division of the two main bronchi
3 layers of intercostal muscle
external intercostal
internal intercosta
inner most intercostal muscle
most powerful respiratory muscle
diaphragm
less powerful intercostal
intercostal
accessory msucles
neck muscles- used in extreme distress
all respiratory muscles are..
skeletal and not smooth
smooth muscle
involuntary, non striated –> function in contraction of internal organs e.g. stomach. slow but sustained. spinal shaped muscle, cells are uninucleate
skeletal muscle
rapid contraction but tire quickly, striated, cells are multinucleate, attached to bone via tendon, body movement
Pleura
the pleural cavity is the thin fluid-filled space between the two pulmonary pleurae (visceral and parietal) of each lung. A pleura is a serous membrane which folds back onto itself to form a two-layered membranous pleural sac.
parietal pleura
thoracic cavity
visceral pleura
lines lungs
pleural cavity
between parietal and visceral pleura –> separates cavities
2 factors to overcome whilst breathing
resistance and compliance
resistance
resistance of respiratory tract to airflow during inspiration and expiration
–> affected by diameter of the airways
compliance
measure of the lungs ability to stretch and expand
low compliance
fibrosis
high compliance
emphysema
resistance is predominately an
expiratory problem and increases respiration rate
pneumothorax
pleural seal broken. Negative pressure cannot be generated causing bad ventilation–> lungs collapse –> elastic recoil of alveoli
atmospheric pressure
760 mm Hg
order of pleura
parietal on outside of lung cavity, pleural cavity in-between ribs and lungs, visceral- surrounds the lungs
intrapulmonary pressure
within the lungs- 760
intraplural pressure
pleaural cavity -756
transpulmnary pressure
760-756= 4 mm Hg
transpluaral pressure
pressure across wal of an organ–> Pip= atm
Boyles law
pressure and volume of a gas have an inverse relationship–> top is held constant
as volume decreases, pressure increases
cervical pleura extends
2.5cm above clavicle
lower pleura
below 12th rib margin posteriorly