ch. 39 Flashcards
is ATP needed for passive diffusion?
no
what is passive diffusion?
diffusion across membranes of O2 and CO2 from high to low concentration
what is needed for respiratory surfaces? what are they surrounded by?
moisture; a thin layer of water
what is fricks law of diffusion?
diffusion rate = diffusion coefficient * surface area * pressure difference / diffusion difference
what are the three best ways to optimize diffusion rate?
- increase surface area
- decrease diffusion distance
- increase concentration difference
what is the order of organisms in least to most complexity of gas exchange systems?
single cell organisms —> amphibians —> echinoderms —> insects —> fish —> mammals
what are gills?
specialized tissues projecting into water for O2 exchange
what animals have external gills?
some fishes and some amphibians
what is the disadvantage of external gills?
they are vulnerable
what are the two types of internal gills?
branchial and opercular
what is the advantage of internal gills?
they are protected
what is ram ventilation?
when an organism swims with their mouth open to force water over gills (constantly need to swim)
what is a buccal-opercular pump?
expansion and contraction of the mouth cavity powers breathing, promoting movement of either water or air into the gills or lungs
buccal open and opercular closed —> buccal fills —> buccal closed and opercular open —> water flows over gills in one direction
what animals use cutaneous respiration?
mostly amphibians; some fishes and sea snakes
what is used for cutaneous respiration?
highly vascularized skin with dense capillaries close to the surface
what is important about cutaneous respiration?
obligatory and facultative
what animals have a tracheal system?
arthropods
what are spiracles?
openings in the skin that may open/close that connect to a tubular network for respiration
what does the tracheal system consist of?
spiracles, trachea, and tracheoles
what is the tracheal system?
a network of small tubes that carries oxygen to the entire body
why were gills replaced by paired lungs?
- gravity and lack of support
- water loss though thin tissue
how do paired lungs minimize evaporation?
- transport air internally via tubes
- saturate inspired air with moisture
- they have a thin fluid layer and membrane
what is the process of positive pressure breathing?
air is taken first into the mouth through the nostrils, and then pushed by positive pressure into the lungs by elevating the throat and closing the nostrils
what animals use positive pressure breathing?
amphibians
what is the buccal cavity?
the oral cavity
what is the gas exchange process of positive pressure breathing?
Nostrils open:
• Buccal cavity
• Drop buccal floor
• Air comes in
– Nostrils close:
• Raise buccal floor
• Force air into lungs
what can positive pressure breathing be augmented with?
cutaneous
what animals use negative pressure breathing?
reptiles and mammals
what has a higher surface are, negative or positive pressure breathing?
negative
what is used in negative pressure breathing?
the thoracic cavity and muscle action
what are characteristics of air sacs?
they hold air but perform no exchange; complete respiration
what are parabronchi?
gas exchange center in avian lungs that have a two-breath cycle
what are characteristics of avian lungs?
1-way movement, only fresh air, very efficient, high metabolic rate
what are conduction structures in the mammalian respiratory system?
they move air and perform no exchange
includes:
- nose
- pharynx
- larynx and trachea
- bronchi
- bronchioles
additional roles
- filter air
- warm air
- communication
what is the function of alveoli?
gas exchange center
what are structural characteristics of alveoli?
- high surface area (80 m^2)
- two cells thick
- very sensitive
describe inhalation
- external intercostal and diaphragm contract
- thoracic volume increases and pressure decreases
- creates negative pressure
- air passes into the lung due to the difference in pressure
- thorax and lungs —> elastic tension
describe exhalation
- external intercostal and diaphragm relax
- elastic tension is released (volume decreases and pressure increases)
- non-forced inhalation
- abdominal muscles may forcible contract
- produce greater exhalation
what is tidal volume?
the volume of air inhaled in a single, normal breath
what is the average tidal volume at rest for a human?
500 mL
what drives breathing rate?
CO2 pressure
what is hypoventilation?
increase in CO2 pressure
what is hyperventilation?
decrease in CO2 pressure
what does the respiratory control center initiate when you are holding your breath?
– Blood PCO2 ↑
– Blood PO2 ↓
– Blood H2CO3 ↑
– Blood pH (H +) ↓
– Chemoreceptors stimulated
– Impulse to RCC
– RCC impulse to EI & Diaphragm
– Involuntary inhalation occurs
what factors affect respiratory pigments?
- pigment type
- temperature
- pH
- CO2
- loading vs unloading
what is binding affinity?
the ability to hold O2 (P50 = 50% saturation)
what is hemoglobin (Hgl)?
- found in RBCs
- 4 heme groups
- 4 Fe atoms
- oxyhemoglobin
- deoxyhemoglobin
- each hemoglobin can bind 4 O molecules
what is a heme group?
centralized iron-containing group that is surrounded by the alpha and beta subunits of hemoglobin
what is myoglobin?
- protein found in muscles
- one Fe atom
- high binding affinity
- found in marine animals
what is alveolar gas?
PO2: partial pressure of oxygen in the alveoli (105 mmHg)
PCO2: 40 mmHg
what is the partial pressure in arterial blood?
PO2: 100 mmHg
PCO2: 40 mmHg
how is CO2 transferred in the respiratory system?
CO2 binds to proteins in Hgl
- carbonic anhydrase converts CO2 to H2CO3 and removes from the plasma
- decrease in affinity for O2
what organs do URIs affect?
nose, sinuses, pharynx, larynx
what are examples of URIs?
Sinusitis, Laryngitis, Tonsillitis, Flu, Common cold, Epstein-Bar, Pertussis, & Step throat
what organs do lower respiratory infections affect?
bronchus, bronchioles, and lungs
what are examples of LRIs?
bronchitis, pneumonia, and tuberculosis
(can be viral or bacterial)
what are chronic obstructive pulmonary diseases?
Long-term obstruction of air ways (ex: Chronic bronchitis, Asthma, and Emphysema)
what is asthma?
- inflammation is triggered by environmental factors; Inflammation obstructs the airways
- genetic and environmental
- allergens and histamines
- treatment: dialators/anti-inflammatory
what is emphysema?
- mostly arises from smoking (90%)
- walls of alveoli are destroyed, decreasing surface for gas exchange
- lose elasticity
- lungs become fibrotic
what is black lung?
– Pneumoconiosis
– Coal miners
– Coal dust
• Repeated exposure
• Inflammation
• Causes scarring
– Not genetic
– leads to difficulty talking
what is lung cancer?
- majority of cancer deaths
- originates in bronchi
- metastasizes quickly
- 3% survival after metastasis
- chronic cough with blood
what are the types of lung cancer and their causes?
– Small cell Lung Cancer
• Smoking & air pollution
• 10 – 15% of all cases
– Non-Small cell Lung Cancer
• 80% of all cancer
• 85 – 90% of all cases
– Mesothelioma
• Asbestos exposure
• Pleura of lung
