Respiratory System Flashcards
What is Physiological respiration?
Physiological respiration:
process by which animals exchange gases with their surroundings – how they take in O2 from the environment and deliver it to body cells, and remove CO2 from body cells and deliver it to the environment
What is cellular respiration?
Cellular respiration: includes all the oxidative reactions that lead to production of ATP in mitochondria of animal cells – where O2 is used and CO2 is released
What two things does gas exchange in animals depend on?
how gas exchange occurs in an animal depends on its respiratory medium and the nature of its respiratory surface
What is respiratory medium?
the respiratory medium for aquatic animals is water, for terrestrial animals, it is air – amphibians use both
What is breathing?
exchange of gases with the respiratory medium is called breathing, whether the medium is air or water
What is the respiratory surface?
the respiratory surface, formed by a layer of epithelial cells, is the interface between the body and the respiratory medium
What are the two structural properties that face a high rate of diffusion?
respiratory surfaces typically have two structural properties that favor a high rate of diffusion – they are thin, and they have large surface areas
By what method does gas exchange occur in animals?
in all animals, exchange of O2 and CO2 across the respiratory surface occurs by simple diffusion – movement of molecules from a region of higher concentration to a region of lower concentration
What does this equation indicate?
(t = x2/4D)
Rate of diffusion:
inversely proportional to the square of the distance over which diffusion occurs
This expression appears to be related to the time (t) it takes for diffusion to occur. It suggests that the rate of diffusion is inversely proportional to the square of the distance (x) and directly proportional to the diffusion coefficient (D). This relationship is derived from the solution to Fick’s Second Law in a one-dimensional system under certain conditions.
The equation suggests that the time of diffusion is directly proportional to the square of the distance (x2) and inversely proportional to the diffusion coefficient (D). This implies that if the distance is increased, the time for diffusion will increase, but if the diffusion coefficient is increased, the time for diffusion will decrease.
What does this equation mean? (dQ/dT = DA (dC/dx)
Rate of diffusion
directly proportional to the surface area across which diffusion occurs (dQ/dt = DA (dC/dx))
becomes higher with larger concentration gradients and with increasing temperature (dQ/dt = DA (dC/dx))
This equation represents the rate of diffusion (dQ/dt) and is proportional to the product of the diffusion coefficient (D), the surface area (A), and the concentration gradient (dC/dx). This relationship highlights that a larger surface area, a steeper concentration gradient, and a higher diffusion coefficient contribute to a higher rate of diffusion.
This statement reinforces the idea that a higher concentration gradient (dC/dx) contributes to a higher rate of diffusion. Additionally, it mentions that increasing temperature can also lead to a higher rate of diffusion. Higher temperatures generally increase the kinetic energy of particles, making them move more rapidly and thereby facilitating the diffusion process.
What comprises the respiratory surface in some small animals?
What animals does this include?
in some relatively small animals, such as sponges, ctenophores, roundworms, flatworms, and some annelids, the entire body surface serves as the respiratory surface
What forms the respiratory surface in large animals?
in larger animals, specialized structures (gills and lungs) form the primary respiratory surface for exchanging gases with water and air
in water-breathing animals, ____ are ____ of the body – they extend outward into the respiratory medium
gills . . . evaginations
What are tracheal systems?
a system of branching tubes channels air from the outside to the internal organs and most individual cells of the animal
What forms the respiratory surface in insects?
in insects, a system of branching tubes (tracheal system) channels air from the outside to the internal organs and most individual cells of the animal
in terrestrial animals, ____ are ____ of the body surface, deep in the body interior where they are less susceptible to drying out
lungs . . . invaginations
While must the respiratory surface be wetted?
gases must dissolve in water to enter and leave epithelial cells – the respiratory surface must be wetted, either directly by the respiratory medium or by a thin film of water
What are evaginations?
Evagination refers to the outward folding or projection of a structure
What is responsible for gas exchange? (think general)
the respiratory system is responsible for gas exchange
What does the respiratory system consist of?
consists of all parts of the body involved in exchanging air between the external environment and the blood
What is invagination?
Invagination refers to the inward folding or infolding of a structure.
What do gills extend into for water-breathing animals?
in water-breathing animals, gills are evaginations of the body – they extend outward into the respiratory medium
What is perfusion?
perfusion – the flow of blood or other body fluids to the internal side of the respiratory surface
most animals have structures that ___ ___ ___ of the respiratory surface?
increase the area
What three major things does the respiratory system contain in mammals?
in mammals, includes the airways leading to the lungs, the lungs themselves, and the structures of the chest used to move air through the airways, into and out of the lungs
What 2 features help animals maintain the difference in concentration between gases outside and inside the respiratory surface, maximizing the rate of gas exchange?
Ventilation and perfusion
What is ventilation?
ventilation – the flow of the respiratory medium (air or water) over the external side of the respiratory surface
What are external gills?
external gills are gills that do not have protective coverings
extend out from the body, in direct contact with water
in animals whose skin serves as the respiratory surface, the body is ____________________?
body is elongated or flattened
What does the respiratory surface have in animals with gills?
in animals with gills, the respiratory surface has highly branched structures with many small projections
Water vs air:
What takes more energy to move over respiratory surface?
it takes significantly more energy to move water than air over a respiratory surface
What does the respiratory surface have in animals with lungs or tracheae?
in animals with lungs or tracheae, the respiratory surface has many branched tubes, folds, or pockets
Water vs air:
What holds more O2?
What is O2 content affected by?
water holds less oxygen than air, and O2 content is affected by temperature and solutes
What 3 properties of air reduce the energy required for ventilation?
relatively high O2 content, low density, and low viscosity of air greatly reduce the energy required for ventilation
How do animals that live in water exchange gases?
most animals that live in water exchange gases through the skin or gills – aquatic mammals exchange gases through lungs
What is the down side of an air medium?
however, animals lose water during breathing
Water vs air:
Rate of diffusion of gas molecules?
gas molecules diffuse faster in air than in water
Down side to external gills?
exposed to mechanical damage and must be immersed in water to keep them from collapsing or drying
How do animals that live on land exchange gases?
most animals that live on land exchange gases through lungs – some exchange gases through gills, and others exchange gases using a tracheal system
What are internal gills?
internal gills are located within a body chamber and have a cover that protects the gills from drying
Down side of internal gills?
water must be brought to internal gills
What environments have animals with external gills?
Examples?
animals with external gills are limited to relatively protected aquatic environments
EXAMPLES: certain annelids and mollusks, aquatic insects, larval forms of some bony fishes, and certain amphibians
What do clams and oysters have to work cooperatively with gills?
clams and oysters use beating cilia to circulate water over their internal gills
Where find animals with internal gills?
gills allow animals to live in diverse aquatic habitats and moist terrestrial habitats
What do cuttlefish use cooperatively with gills?
cuttlefish use contractions of the muscular mantle to pump water over their gills
What do body fish feature relative to their gills?
gills of bony fishes extend into a chamber covered by gill flaps or opercula, which help ventilate the gills
What is countercurrent exchange?
How does this work?
countercurrent exchange uses one-way flow of water over the gills to maximize the O2 and CO2 exchanged with water
water flowing over the gills moves in a direction opposite to the flow of blood under the respiratory surface
at any point along the gill filament, the water is more highly oxygenated than the blood – O2 diffuses from the water into the blood across the entire respiratory surface
How do insects breathe?
insects breathe air through air-conducting tubes (tracheae), which are invaginations of the outer epidermis of the animal reinforced by rings of chitin – the material of the exoskeleton
How much oxygen does counter current exchange remove from water?
countercurrent exchange removes 80-90% of water’s O2 content
What gets air in and out of insects?
alternating compression and expansion of the body pumps air through the tracheal system
How does air enter and leave the tracheal system of insects?
What are these structures called?
air enters and leaves the tracheal system at openings in the chitinous exoskeleton (spiracles), which open and close in coordination with body movements
What is a secondary purpose of trachea?
at places within the body the tracheae expand into internal air sacs that act as air reservoirs
Where are trachea and what do they connect in insects?
trachea lead from the body surface and branch extensively to almost every cell inside the animal
What type of lungs do lungfishes and mature amphibians have?
lungfishes and mature amphibians have lungs consisting of thin-walled sacs – air is obtained by positive pressure breathing, a gulping motion that forces air into the lungs
What are at the ends of trachea in insects?
the finest branches (tracheoles) are dead-end tubes with very small fluid-filled tips that are in contact with cells of the body, forming the respiratory surface
What adaptations allowed for animals to live in terrestrial environments?
lungs are one of the primary adaptations that allowed animals to live in terrestrial environments
What does air flow throw in birds to gas exchange?
within the lungs, air flows through fine, parallel tubes (parabronchi)
What is positive pressure breathing?
a gulping motion that forces air into the lungs
How do reptiles and mammals fill their lungs?
reptiles and mammals fill their lungs by negative pressure breathing – muscular contractions that expand the lungs, lowering the pressure and causing air to be pulled inward
What is negative pressure breathing?
muscular contractions that expand the lungs, lowering the pressure and causing air to be pulled inward
What do birds have in addition to lungs?
in addition to paired lungs, birds have nine pairs of air sacs that branch off the respiratory tract and allow air to flow in one direction through the lungs, rather than in and out
What are the muscular structures of airway?
the walls of the smaller bronchi and bronchioles contain smooth muscle cells that contract or relax to control the amount of air flowing to and from the alveoli
What has the most efficient and complex lungs and what makes this possible?
in birds, a countercurrent exchange system provides the most complex and efficient vertebrate lungs
What does the epithelium of bronchi contain?
Why?
the epithelium of bronchi contain cilia and mucus-secreting cells that trap bacteria and airborne particles and moves them upward into the throat
What are parabronchi?
What do they allow for
parallel tubes that are surrounded by a capillary network – blood flows in the direction opposite to air flow (countercurrent exchange)
What can tobacco smoke do to cilia in lungs?
tobacco smoke paralyzes the cilia
What separates thoracic and abdominal cavity?
a dome-shaped sheet of skeletal muscle (the diaphragm) separates the chest cavity containing the lungs from the abdominal cavity
What are the non-muscular airway structures?
the larynx, trachea, and larger bronchi are nonmuscular tubes encircled by rings of cartilage
Seven structures that air moves through in humans?
- nostrils and mouth
- throat (pharynx)
- “voice box” (larynx)
- windpipe (trachea)
- (bronchi)
- (bronchioles)
- (alveoli), s
air enters through the nostrils and mouth
air moves through the throat (pharynx) and “voice box” (larynx) into the windpipe (trachea)
the trachea branches into two airways (bronchi) leading to the two lungs
inside the lungs, the bronchi narrow and branch, becoming progressively narrower and more numerous
terminal airways (bronchioles) lead into cup-shaped pockets (alveoli), where gas exchange occurs
How do lungs do exhalation?
lungs are elastic and resist stretching as they are filled – stretching stores energy, which can be released to expel air from the lungs
when a person at rest exhales, the diaphragm and rib muscles relax – elastic recoil of the lungs expels the air
What muscles allow for inhalation?
contraction of the diaphragm and external intercostal muscles between the ribs brings air into the lungs by a negative pressure mechanism
What are lungs covered by?
What does this allow for?
lungs are covered by a double layer of epithelial tissue (the pleura) – a slippery fluid between the inner and outer layers allows the lungs to move freely within the chest cavity
What happens to exhalation when oxygen demand increases?
when oxygen demand increases, air is expelled forcefully by contraction of abdominal wall muscles and internal intercostal muscles, reducing the volume of the chest cavity
What is tidal volume?
tidal volume is the volume of air entering and leaving the lungs during inhalation and exhalation
about 500 mL at rest, increasing with physical activity
What is vital capacity?
vital capacity is the maximum tidal volume of an individual
about 3,400 mL in females and 4,800 mL in males
What is residual volume?
residual volume is the amount of air that remains in the lungs after forceful exhalation
about 1,000 mL in females and 1,200 mL in males
What can higher brain centers do in breathing?
signals from higher brain centers in the cerebrum can override the respiratory controls of the brain stem
What acts as the primary stimulator of inhalation at rest?
signals from a dorsal group of interneurons in the medulla act as the primary stimulator of inhalation, causing the diaphragm and the external intercostal muscles to contract
What role does the pons have in breathing?
two interneuron groups in the pons modulate the signals from the medulla so that breathing is gradual and controlled
Where is the rate and depth of breathing controlled?
the rate and depth of breathing is controlled by groups of interneurons in respiratory centers of the medulla and pons, which form part of the brain stem
What else can breathing rate and depth be modified by?
breathing rate and depth are modified by emotional states – controlled by centers in the limbic system of the brain
Where are 3 places chemoreceptors in body located to modulate breathing?
chemoreceptors are located centrally on the surface of the medulla, and peripherally in the carotid arteries (carotid bodies) and the aorta (aortic bodies)
What must be true of PP for CO2 to diffuse outward across respiratory surface?
for CO2 to diffuse outward, its partial pressure must be greater inside than outside
What do automated controls in the lungs do?
Reduced O2 concentration?
Increased O2 concentration?
automated controls within the lungs match the rates of ventilation and perfusion by responding to O2 concentrations in the blood
reduced O2 concentration causes smooth muscles in the walls of arterioles in the lungs to contract, giving blood more time to pick up O2
rising blood O2 concentration causes the smooth muscle cells in arteriole walls to relax, increasing the rate of blood flow through lung capillaries
What sends signals for breathing during exercise?
during physical exercise, a ventral group of interneurons in the medulla sends signals for both inhalation and exhalation
What must be true of PP for O2 to diffuse inward across respiratory surface?
for O2 to diffuse inward across a respiratory surface, its partial pressure must be greater outside than inside
What do respiratory centers in the brain integrate sensory information from?
the respiratory centers in the brain integrate sensory information sent by chemoreceptors that monitor O2 and CO2 levels in the blood and body fluids
What do receptors in medulla detect to modulate breathing?
receptors of the medulla detect pH changes in cerebrospinal fluid – determined mostly by CO2 concentration in the blood
What is partial pressure?
when gases are present in a mixture, the pressure of each individual gas (its partial pressure) is determined by its proportion in the mixture
What does CO2 and O2 diffuses between in lungs and why does this happen?
O2 and CO2 diffuse passively down partial pressure gradients between alveolar air and plasma in pulmonary capillaries
Normal atmospheric pressure?
in dry air at sea level, the total atmospheric pressure under standard conditions is 760 mm Hg
Where does CO2 produced by cellular oxidation diffuse to and what are the pressure of CO2 in these regions?
CO2 produced by cellular oxidations diffuses from active cells into interstitial fluid (PCO2 ~46 mm Hg), then into the capillary networks (PCO2 ~40 mm Hg)
What percentage of O2 in blood in carried by what?
about 98.5% of the O2 in blood is carried by hemoglobin and about 1.5% is carried in solution in the blood plasma
Where does O2 go after diffuse into blood plasma?
after entering the plasma, O2 diffuses into erythrocytes, where it combines with hemoglobin
Partial pressure/percentage of O2 and CO2?
the proportion of O2 in dry air is about 21% – the partial pressure of O2 (PO2) is 760 X 21/100, or 160 mm Hg
the partial pressure of CO2 (PCO2) in dry air is 760 X 0.04/100, or about 0.3 mm Hg
What does hemoglobin contain?
hemoglobin has four heme groups, each containing an iron atom that can combine reversibly with an O2 molecule
What does the top part of the hemoglobin-O2 dissociation curve show?
the top plateau part of the S-shaped curve (above 60 mm Hg) is in the PO2 range found in pulmonary capillaries – in this range, blood remains highly saturated
What does the binding of O2 to hemoglobin cause?
combination with hemoglobin lowers the PO2 of the plasma and allows additional O2 molecules to diffuse into the blood
What facilitates the reaction of CO2 into carbonic acid?
this reaction takes place both in blood plasma and erythrocytes, facilitated by the enzyme carbonic anhydrase
What is the reversible combination of O2 and hemoglobin related to and shown by?
the reversible combination of hemoglobin with O2 is related to the partial pressure of O2 in a pattern shown by the hemoglobin-O2 dissociation curve
What does the steep part of the hemoglobin-O2 dissociation curve show?
the steep part between 0 and 60 mm Hg is in the PO2 range found in body capillaries – in this range, small changes in PO2 result in a large change in O2 bound to hemoglobin
What contributes to the release of O2 from hemoglobin?
several factors contribute to the release of O2 from hemoglobin, including increased acidity (lower pH)
What is the P O2 and pH in lungs?
In the alveoli, in which the PO2 is about 100 [104mmhg] mm Hg and the pH is 7.4, most hemoglobin molecules are 100% saturated, meaning that almost all have bound four O2 molecules.
How does low pH in body tissues help?
What is the lower pH formed by?
acidity increases in active tissues – oxidative reactions release CO2, which combines with water to form carbonic acid (H2CO3)
lowered pH alters hemoglobin’s conformation, reducing its affinity for O2, (the Bohr effect) – O2 is released and used in cellular respiration
What happens to the majority of CO2? How much is this?
some CO2 remains in solution in the plasma – most (about 70%) combines with water to produce carbonic acid (H2CO3), which dissociates into bicarbonate (HCO3–) and H+ ions
What happens to the hydrogen ions produced by the dissociation of carbonic acid?
most H+ ions produced by the dissociation of carbonic acid combine with hemoglobin or proteins in the plasma – which buffers blood pH, maintaining it at pH 7.4
Why is pH homeostasis important?
pH homeostasis is important because many enzymes are sensitive to minor changes in pH
How does CO2 leave the body if it dissociates into carbonic acid?
as blood enters the capillary networks surrounding the alveoli, the process of CO2 uptake is reversed – CO2 diffuses from blood into the air
What is CO?
What is it produced by?
Why is it harmful?
carbon monoxide (CO), a colorless gas produced when fuels are incompletely burned, binds so strongly to hemoglobin that it displaces O2
What happens if CO is inhaled in high quantities?
if CO is inhaled in high quantity, the reduction in oxygen delivered to the brain can lead to brain damage and death by hypoxia (lack of oxygen)
Why can people die from CO poisonings without noticing?
because the brain regulates breathing based on CO2 levels rather than O2 levels, victims breathing CO can become unconscious and die from hypoxia without noticing anything
Study the study guide material for the respiratory system!
Study the study guide material for animal nutrition!
Study the study guide material from the case studies!
