Lecture 13- Respiratory Flashcards
is the process of obtaining oxygen from the external environment and eliminating carbon dioxide
respiration
oxidative processes
within cells
cellular respiration
exchange of O2 and CO2 between the organism and its environment
External respiration
Gases ___ ___pressure gradients in the lungs and other organs
diffuse down
Gases diffuse down as a result of differences in___ ____
Partial pressure
is the pressure exerted by a particular gas in a mixture of gases
Partial pressure
Components of gas-transfer system
- Breathing movements
- DIffusion of O and CO2 across the respiratory equilibrium
- Bulk transfer of gases by the blood
- Diffusion of O and CO2 across capillary walls
Conditions of gas-exchange regions for diffusion to be effective
- Moist
- Thin
- Relatively large
- In contact with teh environment
Enhances the effectiveness of diffusion
Vascularization
source of O2 or respiratory medium for animal
Air or water
Types of breathing
- Unidirectional
- Bidirectional or tidal
- in most fish gills
- continuous ventilation
- water enters the buccal cavity through the mouth, passes across the gill curtain and exits flowing in one direction
Unidirectional
– in lung ventilation
- with air entering and exiting through the same channel
- ventilation is not continuous
Bidirectional or tidal
Patterns of gas exchange
- Crosscurrent flow
- Uniform pool
- airflow and blood flow cross each other obliquely
- avian lungs
crosscurrent flow
lung ventilation keep the partial pressure of gases within the alveolar spaces uniform through frequent breathing, mixing gases, and absence of significant
barriers to diffusion
Uniform pool
in crosscurrent flow, airflow and bloodflow cross each other _____
obliquely
in uniform pool, where do lung ventilation keeps the partial pressure of gases?
Alveolar spaces
What are some respiratory organs
- Gills or branchia
- Lungs
A series of bones in bony fish and chimaeras
- protects the gills, provides facial support, and is used for respiration and feeding
Operculum
exchange of substance between two fluids in opposite directions
Countercurrent flow/exchange
system of branching ducts conveys air
to the lungs
Respiratory system
hair-like projections
- line the primary bronchus to remove microbes and debris form interior of the lungs
Cilia
alternating inhalation and exhalation or air; ventilates the lungs
Breathing
A frog ventilates its lungs by ___ ___ ___
Positive pressure breathing
what does positive pressure breathing do?
forces air down the trachea
How do mammals ventilate their lungs
Negative pressure breathing
How does air get to alveoli
Trachea –>Primary bronchi (left, right) –> Secondary bronchi (each
lobe) –> Tertiary bronchi –> bronchioles –>Alveoli
envelope the lungs
Pleural cavities
carries O2 blood from
each lung to heart
2 pulmonary veins
carries dO2 blood to
each lung
1 pulmonary artery
The primary muscle of respirations
Diaphragm
Function of Diaphragm for Constraction during inspiration
- Increases volume of thoracic cavity
- Decreases pressure of thoracic cavity
- Air moves into lungs (high -> low
presssure)
Diaphragm function during forced contraction (voluntary)
Used for defecation, urination and labor
How does Diaphragm works for defecation, urination and labor
- Increases pressure in abdominal cavity
- Pushes on abdominal organs to move contents out
Lift ribs to expand chest cavity for inspiration
Intercostal muscles
no blind ended alveoli in and out of which air moves
Avian lungs
voluminous, thin walled diverticula of the lungs which penetrate the centra (pneumatic foramina) except in ratites
Air sacs
___ of the lungs extensively distributed throughout of the body
Diverticula
Where do gas transfer in birds takes place?
Small air capillaries
have the most efficient
vertebrate lungs
Birds
In bird respiratory system; ____ ____ allow oxygen-rich air to pass ____ ____ on both inhalation and
exhalation
Air sacs
Respiratory surfaces
Control of breathing can be:
- Chemical
- Nervous
Chemical control of breathing is dependent to
- Blood CO2 levels
- pH
- Chemoreceptors
Control of breathing; Chemoreceptors
Central : Monitors CSF
Peripheral: Caraotid and aoritic bodies
Nervous control of breathing can be..
- Voluntary
- Involuntary
Voluntary control of breathing
◦ Cerebral cortex
◦ Protective in nature
◦ Limited control
Involuntary control of breathing
- Medullary rhytmicity area
- Pons
Maintains basic rhythm of respiration
Medullary rhythmicity area
Coordinates transition between inspiration and expiration
Pons
Control of Breathing in Humans; when the control center registers a slight drop in pH, it ….
- Increases the depth and rate of breathing
- Excess CO2 is eliminated in exhaled air
Facilitates inspiration and helps control depth of inspiration
Apneustic center
Helps control rate of respiration
Pneumataxic center
- This group maintains the basic rhythm of respiration.
- The pons coordinates transition between inspiration and expiration.
Brainstem group (involuntary)
Cerebral cortex group
Voluntary
Influence the timing of inspiratory cut-off by providing a tonic input to the respiratory pattern generators located in the inspiratory center
Pneumotaxic center
Pneumotaxic center influences the respiratory response to what stimuli?
Hypercapnia
Hypoxia
Lung infection
- found in the lower pons
- source of impulses that terminate inspiration “inspiratory cut-off switch”
Apneustic center
inactivation of Apneustic center results in
apneustic breathing
rhythmic respiration
with a marked increase
in inspiratory time and
a short expiration
phase
Apneustic breathing
Two groups of medullary center
- Inspiratory dorsal respiratory group (DRG)
- Experiatory ventral respiratory group (VRG)
- is the site of projection of proprioceptive afferents from the respiratory muscles and chest wall.
- site of origin of the normal rhythmic respiratory drive consisting of repetitive bursts of inspiratory action potentials.
DRG (inspiratory dorsal respiratory group)
innervates respiratory effector muscles through the phrenic,
intercostal, and
abdominal respiratory
motoneurons
ventral respiratory group (VRG)
– most important factor
H+ concentration
aids the H+ concentration by forming carbonic acid
Carbon dioxide
are complexes of proteins and metallic ions
Respiratory pigments
oxygen diffuses across the respiratory epithelium into the blood - combines with a
Respiratory pigment
most vertebrates and some invertebrates use
Hemoglobin
What is the Bunsen solubility coefficient for oxygen in blood at 37°C
- 2.4 ml of oxygen per 100 ml of blood per atmosphere of oxygen pressure
What is the concentration of oxygen in a physical solution (not bound to a respiratory pigment) in human blood at normal arterial Po2?
0.3 ml of oxygen per 100 ml blood, or 0.3 vol % oxygen
What is the total oxygen content of human arterial blood at a normal arterial Po2
20 vol %
How does the combination of oxygen with hemoglobin affect oxygen content in blood
causes a 70-fold increase in oxygen content
color of a respiratory pigment changes with its
Oxygen content
Color of hemoglobin when loaded with O2
Bright red
what color is hemoglobin when it becomes deoxygenated?
Dark maroon-red
- tetrameric protein
- four folded polypeptide chains of amino acids
Globin
- four iron containing porphyrin prosthetic groups
- transports oxygen
heme
Molar weight of Hemoglobin
68,000
Hemoglobin is composed of?
Heme and protein globin
two dimers, α1β1, and α2β2, each of which is a tightly cohering unit
Globin molecule
more loosely connected to each other by salt bridges, except that the two β chains do not touch
Two dimers
alters these bridges; conformational changes in the hemoglobin molecule
Oxygenation
ferrous state (Fe2+) bound by porphyrin ring of the heme, forming coordinate links with four pyrrole nitrogens
Iron
Fe2+ is oxidized to Fe3+; does not bind oxygen; nonfunctional
Methemoglobin
reduces methemoglobin to the functional ferrous form
RBC with methemoglobin reductase
red color of blood and its oxygen-combining ability
Heme group
one hemoglobin molecule binds four oxygen molecules
Oxyhemoglobin
form of hemoglobin with absence of O2
Deoxyhemoglobin
act either to oxidize hemoglobin or to inactivate methemoglobin reductase, thereby increasing the level of methemoglobin and impairing oxygen transport.
Certain compounds (eg. Nitrated and Chlorates)
- formed from the incomplete combustion of carbon dioxide
- interferes with the binding of oxygen to hemoglobin
- has an affinity a higher (200X) affinity to hemoglobin than does oxygen
Carbon monoxide (CO)
hemoglobin saturated
with CO
Carboxyhemoglobin
Other blood pigments
Hemerythin
Chlorocruorin
Hemocyanin
Blood pigments in Priapulida, Brachiopoda, Annelida (violet, Fe2+)
Hemerythrin
Blood pigemnts for Annelida; (green,
Fe2+)
Chlorocruonin
Blood pigment for (Mollusca, Arthropoda; blue; deoxygenated: colorless; not packaged in cells)
Hemocyanin
How many oxygen can hemoglobin carry
- Four oxygen molecules
relationship between percent saturation and the partial pressure of oxygen
Oxygen dissociation curves
oxygen dissociation curves of other vertebrate
Sigmoid
What does P50 represent in terms of hemoglobin’s oxygen affinity?
partial pressure of O2 at which the pigment is 50% saturated with O2
The lower the ___ the higher the oxygen affinity
P50
Condition that Oxygen affinity is reduced
- elevated temperature
- Binding of organic phosphate ligands (DPG, ATP, or GTP by hemoglobin)
- Decrease in pH (increase in H+ concentration)
- Increase in carbon dioxide
a change in the oxygen dissociation curve caused by carbon dioxide levels
Bohr effect
predominant form of CO2
Bicarbonate (HCO3^-)
Total CO2 content varies with
PCO2
A decrease in pH at a constant PCO2 is associated with the fall in _____
bicarbonate
Most of the bicarbonate in the blood is in the
___
plasma
most O2 combines with hemoglobin in red blood cells to form
Oxyhemoglobin
some CO2 combines with hemoglobin to form
carbaminohemoglobin
CO binds to Hb as
carboxyhemoglobin
normal, quiet breathing typical of an animal at rest
Eupnea
increase or decrease in the amount of air moved into and out of the lungs by changes in the rate and depth of breathing
Hyperventilation or Hypoventilation
increased lung ventilation due to increased breathing in response to elevated carbon dioxide production
Hypernea
Absence of breathing
Apnea
labored breathing associated with an unpleasant sensation of breathlessness
Dyspnea
increase in breathing rate w/o an increase in the depth of breathing
Polypnea
Average rate of breathing of an adult
14-20 cycles/minute
Rise in temperature will decrease the _____-
Oxygen affinity -> making oxygen transfer between oxygen and blood difficult
contains γ chains, rather than adult β chains, has a higher oxygen affinity than adult hemoglobin
Human fetal hemoglobin
influenced by properties of the medium and requirements of the
animal
Structure of gas-transfer system
minimize diffusion distances in water, creating a thin layer of water over the respiratory surface
Design of fish gills
properties of the alveolar wall and the surface tension at the liquid-air interface
Lung wall tension
force that tends to minimize the area of a liquid surface
Surface tension
- low surface tension of the liquid lining the lungs
- lipoprotein complexes that bestow a very low surface tension on the liquid-air interface
Surfactants
predominant lipid in these lipoprotein complexes
Dipalmitoyl lecithin
newborns produce no lung surfactants = cannot inflate their lungs at birth without assistance (premature babies)
Newborn respiratory distress syndrome
- the volume of air an animal inhales and exhales with each breath
Tidal volume
Average tidal volume in resting humans
500 mL
- maximum volume of air that can enter the lung;
- about 3.4 L and 4.8 L for college-age females and males, respectively
Vital capacity
amount of air that persists in the lungs after maximal expiratory effort
Residual volume
sum of residual volume and vital capacity
Total lung capacity
tidal volume minus residual volume (anatomic dead-space volume)
Alveolar ventilation volume
Respiratory system of Insects and other terrestrial arthropods
- consists of branched tracheae
- Oxygen enters tracheae at spiracles
- Tracheae branch until end in tracheoles that are in direct contact with body cells
movement of the ribs, diaphragmaticus muscles and liver
Crocodilians
movement of the pelvic girdle
in Turtles
