Chapter 49-The Respiratory System Flashcards
Oxygen is needed why?
final electron acceptor during electron transport. Without oxygen, animal cells obtain insufficient energy to survive
Gas exchange
- the gases diffuse into the aqueous layer covering the epithelial cells that line the respiratory organs
- diffusion of gasses is passive, driven only by the difference in O2 and CO2 concentrations on the two sides of the membranes and their relative solubilities in the plasma membrane
Body surface for gas exchange
only in amphibians and annelids, a few others
tracheal tubes
insect’s structure for gas exchange
lungs
reptiles, birds, and mammals structure for gas exchange
Gills
specialized extensions of tissue that project into water, extract oxygen from water and release carbon dioxide
-increase surface area for diffusion
Internal gills
gills of bondy fishes are located between oral cavity and opercular cavities
- two cavities function as pumps that alternately expand.
- move water into mouth, through gills, and out of the fish through the open operculum or gill cover
Lamellae
each gill filament is made of these, thin membranous plates that project into water flow
countercurrent flow
blood flows opposite to direction of water movement in lamellae
- maximizes ocygenation of blood
- gills are more efficient of all respiratory organs
cutaneous respiration
amphibians who exchange gas through body surface
1 atm of pressure
is a pressure of 760mm Hg
partial pressure
pressure contributed by a gas (i.e. oxygen) to the total atmospheric pressure
how does pressure change
changing the number of molecules exerting the force or by changing the surface area
positive pressure breathing
force air into their lungs by creating a positive pressure in the buccal cavity (push oxygen into lungs) (frogs)
negative pressure breathing
expand rib cages by muscular contractions, creating lower pressure inside the lungs
Tubes of respiratory system
larynx, glottis, trachea, right and left bronchi, bronchioles, alveoli
partial pressure of oxygen depleted blood returning from systemic circulation
partial pressure of 40mm Hg
Partial pressure of oxygen in alveoli
105 mm Hg
partial pressure of oxygen in blood leaving lungs
100mm Hg
partial pressure of CO2 in alveoli
40 mm Hg
partial pressure of CO2 in blood leaving lungs
40 mm Hg
partial pressure of CO2 in blood entering lungs
46 mm Hg
How do lungs move
attached to thoracic cavity through pleural cavity
- during inhalation, thoracic volume increases through contraction of external intercosal muscles (expands rib cage) and contraction of the diaphragm (expands volume of thorax and lungs
- -this increases surface area and decrease pressure to below atmospheric pressure
tidal volume
volume of air moving in and out of lungs in a person at rest
vital capacity
macimum amount of air that can be expired after a forceful respiration
Hypoventilation
insufficient breathing, blood has abnormally high CO2 partial pressure
Hyperventiliation
excessive breathing, blood has an abnormally low CO2 partial pressure
what initiates each breath
neurons in a respiratory control center in the medulla oblongata (autonomic nervous system)
-stimulates external intercostal muscles and diaphragm to contract, causing inhalation
what causes exhalation
the neurons stop producing impulses, respiratory muscles relax
carbonic acid
produced in the event of a rise in blood CO2, lowers blood pH.
COPD
chronic obstructive pulmonary disease
-refers to any disorder that obstructs airflow on a long term basis
Asthma
COPD
-allergen triggers the release of histamine, causing intense constriction of the bronchi and sometimes suffocation
Emphysema
COPD
- alveolar walls break down and the lung exhibits larger but fewer alveoli
- lungs become less elastic
- often caused by smoking
Lung cancer
caused mainly by cigarette smoking
-spreads so rapidly its usually in other organs by the time of diagnosis
Hmoglobin
consists of 4 polypeptide chains
-each chain is associated with a heme group, which binds with oxygen
Bohr shift
pH effect on hemoglobins affinity for 02
- increased CO2 increases H+
- lower pH reduces hemoglobins affinity for O2
- increased temperature has similar effect
transportation of CO2
20% of CO2 is bound to hemoglobin
- 8% is dissolved in plasma
- 72% is in red blood cells
