2. Composition of inspired, expired, and
alveolar air.
Air O2 (%) CO2 (%) N2 et.al (%)
Atmosph
air 20,93 0,03 79,04
Alveolar
air 14,0 5,5 80,5
Expired air 16,0 4,5 79,5
3. O2 consumption is 400 ml/min (at rest)
CO2 elimination is 320 ml/min
Partial pressure depends on % of gase
F.ex.: O2 in air 21%; 760mmHg – 100%
160 mmHg -21%
“Tension of gase” is applied for gase,
dissolved in a liquid
4.
5. Motive force of gases exchange is gradient
of gases tensions
Gas Dry Alveolar air Ven. Bl Arterial Bl Tissu
Inspired air (mmHg)
PO2 160 100 40 100 10-30
O2 = 60 O2 = 70
PCO2 0,23 40 46 43 70-80
CO2 = 6 CO2 = 30
6. Oxygen Transport by blood
O2 dissolved in solution (0,3%)
HbO2 oxyhemoglobin
O2 capacity of blood is maximal amount
of O2, can be connected by 100 ml of
blood.
21,44 ml/ O2 per 100 ml of blood
1g Hb can connect 1,34 ml O2
160 g Hb – 214,4/l; 21,44/100ml
10. Coefficient of oxygen utilization
COU = O2% art - O2% ven ;
O2% art
COU = (19% -13%):19%= 1/3 (30%)
1/3 part of oxygen is utilized by tissues in
rest
11. CO2 transport by blood
Dissolved CO2 (2,4% in arterial blood;
3,6% in venous blood)
HbCO2 (4-4,5%);
H2CO3 (7%); Carbonic anhydrase
Major form is HCO3
- (more than 80%) in
form of NaHCO3 and KHCO3 . They
form basic reserve of blood. 58% CO2 in
ven. and 52% CO2 in arterial blood
15. Indexes of Respiration during
Exercise
MPV (min. pulm.ventilation) increases from 8 l at
rest up to 120-150l/min
CPV (coef.pulm.vent) increases from 1/7 up to
½
O2 consumption increases from 400 ml up to
4000ml/min during exercise;
COU (coefficient of O2 utilization) increases from
30% at rest up to 50-60%
16. Respiration at high altitude
(low pressure)
Alveolar and arterial PO2 is decreased
(hypoxemia). As a result: hyperventilation,
erythropoetins production, Hb, RBC increases
At heights less than 3.000 m HbO2 is 88%
3.000-5.000m hyperventilation, elimination of
CO2 from blood, reduces excitability of
respiratory center.
5.000-6.000m hypopnoe, mountain or altitude
sickness may occur.
7.000-8.000m HbO2 is 50%. Gases can go out
from blood, hermetic mask with (O2+5%CO2)
19. Central control of breathing
Medullary respiratory center
Inspiratory center (dorsal respiratory group)
α- inspiratory neurons (for inspiratory
rhythm and excitation of spinal motoneur)
β- inspiratory neurons (less excitable, for
changing of inspiration to expiration by
activation of inhibitory neurons)
Output to sp.cord: C3-5, Th1-12, then to
inspiratory muscles by phrenic nerve
20. Expiratory center (ventral respiratory
group, n.ambiguous).
75% expiratory neurons, active during
exercise.
Pneumotaxic center (upper 1/3 of pons)
Apneustic center (lower 2/3 of pons)
Hypothalamus
Brain Cortex
21. Respiratory neurons in the brainstem
Respiratory neurons in the brain stem. The effects of various lesions and brain transections. The
spirometer tracings indicate the depth and rate of breathing. DRG-dorsal group of respiratory
neurons; VRG-ventral group of respiratory neurons; NPBL – nucleus parabrahialis (pneumotaxic
center); IC –inferior colliculus; 4th vent-forth ventricle.
22. Rhythmic
impulsation of the
respiratory neurones
of the pre –
Bottzinger’s complex
(pre – BOTC
complex)
IO – inferior olivary
nucleus;
LRN – Lateral reticular
nucleus;
NA – n. ambiguous;
XII – n. of XII pair of
cranial nerves;
5SP – spinal n.
trigeminus;
23.
24. Chemoreceptors
Peripheral – in aortic arch (X),
in carotid synus (IX) ( CO2, O2)
Central - on the ventral surface of the
medulla oblongata ( CO2, ph)
25. Organization of the Carotid body
Type I (glomus) cells
contain
catecholamines. When
exposed to hypoxia,
they release
catecholamines, which
stimulate the cup-like
endings of the carotid-
sinus nerve fibers in
the glossopharyngeal
nerve. The glia-like
type II cells surround
the type I cells probably
have sustentacular
function.
28. The cause of the first inhalation
in the newborn is excess of CO2
in blood
Mechano- and termoreceptors of skin are
also stimulated
29. Non chemical influences on respiration
1.Mechanoreceptors of lungs and bronchiol,
LSR n.vagus, (reflexes of Hering – Breier).
2. Irritant receptors (chemo-, mechano-)
trachea, chemical agents (histamine),
cough, bronchospasm and secretion of
mucous;
3. J – receptors, juxta-capillary; are
stimulated during the hyperventilation,
oedema of lungs tissues.
