Download Internal Respiration and CO 2 Exchange

yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Homeostasis wikipedia, lookup

Organisms at high altitude wikipedia, lookup

Biology 12
Respiratory System Notes
Oxygen is moved to lungs →
CO2 moved away from cells of body→ _______ → outside of body
Air is filtered, warmed and hydrated as moves along air passages
throughout the system
A. Nose
Made of 2 _______ ________
_________ are openings to nasal cavities
Separated by bone or cartilage
Inside nasal cavities have hairs and cilia which filter out
contaminants such as dust, pollen, etc.
 Have sensory receptors in nasal cavities for smell
 Nasal cavities connected to sinuses in the head—i.e. bony cavities
lined with mucous membrane
 Nasal cavities open up into the ___________
Figure 1: Nasal Cavity
B. Pharynx
 Composed of ___________, ___________ and _____________
 Where ________, _________ and ________ are found
C. Larynx
 ______ found on top of trachea—Adam’s apple at front of larynx
 ______ is opening lying above larynx→ moves up and against
____________ when swallowing to block trachea
Figure 2: Larynx
 Larynx contains ________ _______ (mucus membranes and elastic
ligaments) which vibrate as air passes them→ sound
 More narrow cords→
Figure 3: trachea in relation to esophagus
D. Trachea
 Surrounded with cartilaginous c-shaped rings that help maintain
open airways
 Lined with cilia that help keep airway clean by sweeping up
contaminants caught in mucus to throat where swallowed
 ______________—procedure where opening is made in trachea if
 At end of trachea are main ___________
Figure 4: Trachea and larynx
Figure 5: Tracheostomy
E. Lungs
2 lungs—
Each divided into lobes
R lung has 3 lobes and left has 2→
Lobes are further divided into smaller lobules
F. R & L Bronchus (pl.= Bronchi)
 Right and Left main __________→ lead into lungs
 Maintain cartilaginous rings
 Divide to form smaller and smaller diameter and thinner _____
eventually losing cartilage
 Eventually, bronchi become structures called bronchioles which
end in small sacs called _________
Figure 6: Lung structure
G. Alveoli
 Thin structures only 1 cell layer thick—simple squamous
 Covered by capillaries
 Alveoli covered by a thin film of a ____________ __________—
chemical that lowers surface tension—prevents them from
collapsing and clinging due to surface tension of water lining
alveoli which would cause alveoli to collapse
 Infant ___________ ________ __________—where babies do not
produce this and have collapse of alveoli—result is trouble
breathing; treatment = surfactant replacement therapy
Figure 7: Alveoli
Mechanism of Breathing Overview
 Different kinds of respiration
a) Breathing
 Expiration (breathing out)
b) External respiration
c) Internal respiration
d) Cellular Respiration
 ATP production in mitochondria: C6H12O6 + O2 → ATP + CO2 +
H2 O
Respiratory Volumes
a) Tidal Volume
 Volume of air inhaled and exhaled at rest
b) Inspiratory reserve volume
 Forced inspiration
 3.0 L
c) Expiratory Reserve Volume
 About 1.4 L
Note: both inspiratory reserve volume and expiratory reserved volume
are used with physical activity
d) Residual Volume
 Air remaining in lungs even after forced expiration (1.0 L)
 ____________—residual volume builds & not used for gas
exchange and thereby reducing vital capacity
e) Vital Capacity
 Sum of tidal volume + inspiratory reserve volume + expiratory
reserve volume (about 4.5 to 5.7 L)
f) Functional Residual Capacity
 i.e. E.R.V. + R.V. (2.5 L)
g) Dead Space
 E.g. nasal cavities, pharynx, larynx, etc.
Mechanism of Breathing
 Air passes from outside to pharynx → alveoli
 Lungs are in sealed _________ ________
 ____ ______ (with intercostals muscles) forms ____ and ______ of
this cavity
 _____________ (domed muscle) forms lower part of thoracic cavity
 _________ ___________ is double membrane associated with lungs
and thoracic cavity
 One layer attached to lungs exterior and other layer closely adheres
to chest wall and diaphragm
 In between 2 pleural membranes is thin layer of fluid (mostly H2O)
 __________ _________ is about 4mm Hg less than atmosphere—
keeps them together
 _____________—condition whereby air enters intrapleural space
and causes lungs to collapse
 Active process—i.e. requires energy
 _________ center in medulla senses CO2 and H+ levels in blood
plasma→ automatically causes inspiration
 Levels of mostly H+ and CO2 as well as O2 are also sensed by _____
bodies (in carotid arteries) and _______ bodies (in aorta) which are
_______________ that send signal to respiratory center in medulla
via nerves
 The more CO2 and H+ in blood, the higher the rate and depth of
 _________ nerve → nerve to diaphragm that causes contraction
 ___________ nerves → send nerve impulses to intercostals muscles
to contract
 When diaphragm and intercostals muscles contract → expand
volume of thoracic cavity→ lungs expand → negative pressure in
lungs → air enters lungs
 If inhale deeply → stretch receptors in alveoli → inhibitory nerve
impulses to respiratory centre → stops sending signals to diaphragm
and intercostals
 Respiratory center → stops signal to diaphragm and rib muscles →
diaphragm and muscles relax → abdominal organs press against
diaphragm → volume of chest cavity decreases → pressure builds up
→ air is forced out
External Expiration
 Gas exchange (CO2, O2 and H20) in alveoli and pulmonary capillaries
occurs due to ___________
Internal Respiration
External Respiration and 02 Exchange
Blood temp. =
pH of blood = 7.4
Hb has 4 binding sites for oxygen
Oxygen bound to Hb called HbO2 or ______________
Internal Respiration and O2 Exchange
Blood temp =
pH of blood = 7.35 (from cell metabolism)
Hb-02 →
Hb becomes unbound again
Internal Respiration and CO2 Exchange
 CO2 + H20 react in red blood cells to give H2CO3 –a reaction catalyzed
by enzyme __________ anhydrase
Reaction: CO2 + H20 → H2CO3 → [HCO3-] + H+
H+ ions are bound by Hb to produce HHb or _________ Hb
Above allows blood to be buffered against changes in pH
Some CO2 binds to Hb to give ______________________ (HbCO2)
Some very small amount transported as dissolved gas in plasma as
External Respiration and CO2 Exchange
 At alveolar capillaries:
 pH higher and temp. lower than at tissues→ release of CO2 and H+
from Hb
 next HCO3 and H+ combine to form carbonic acid by ___________
______________ enzyme
Reaction: HCO3- + H+ → [H2CO3] → CO2 + H2O
 then carbonic acid is converted into H2O and CO2 by enzyme _____
 Some CO2 also leaves from HbCO2 as well as dissolved CO2 in plasma
leaving the plasma for the alveoli
Driving Force of Gas Exchange
 Recall that gas exchange occurs by diffusion
 This gradient is accomplished by partial pressure differences of PCO2
and PO2
 Blood in pulmonary capillaries has higher PCO2 and low PO2
 Thus, CO2 diffuses out of capillaries into alveoli and O2 diffuses out
from alveoli into capillaries
Effect of PO2/Temperature/pH on Hemoglobin Saturation
a. Oxyhemoglobin Dissociation Curve & PO2
 Notice that as PO2 increases, the oxygen saturation of Hb
increases to a point
 Notice also that at any given PO2, a rise in temperature or a
lowering of pH will result in a lower Hb saturation and therefore
more oxygen given off