Respiratory System

Question 1

What is Physiological respiration?

Answer 1

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

Question 2

What is cellular respiration?

Answer 2

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

Question 3

What two things does gas exchange in animals depend on?

Answer 3

how gas exchange occurs in an animal depends on its respiratory medium and the nature of its respiratory surface

Question 4

What is respiratory medium?

Answer 4

the respiratory medium for aquatic animals is water, for terrestrial animals, it is air – amphibians use both

Question 5

What is breathing?

Answer 5

exchange of gases with the respiratory medium is called breathing, whether the medium is air or water

Question 6

What is the respiratory surface?

Answer 6

the respiratory surface, formed by a layer of epithelial cells, is the interface between the body and the respiratory medium

Question 7

What are the two structural properties that face a high rate of diffusion?

Answer 7

respiratory surfaces typically have two structural properties that favor a high rate of diffusion – they are thin, and they have large surface areas

Question 8

By what method does gas exchange occur in animals?

Answer 8

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

Question 9

What does this equation indicate?
(t = x2/4D)

Answer 9

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.

Question 10

What does this equation mean? (dQ/dT = DA (dC/dx)

Answer 10

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.

Question 11

What comprises the respiratory surface in some small animals?

What animals does this include?

Answer 11

in some relatively small animals, such as sponges, ctenophores, roundworms, flatworms, and some annelids, the entire body surface serves as the respiratory surface

Question 12

What forms the respiratory surface in large animals?

Answer 12

in larger animals, specialized structures (gills and lungs) form the primary respiratory surface for exchanging gases with water and air

Question 13

in water-breathing animals, ____ are ____ of the body – they extend outward into the respiratory medium

Answer 13

gills . . . evaginations

Question 13

What are tracheal systems?

Answer 13

a system of branching tubes channels air from the outside to the internal organs and most individual cells of the animal

Question 13

What forms the respiratory surface in insects?

Answer 13

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

Question 13

in terrestrial animals, ____ are ____ of the body surface, deep in the body interior where they are less susceptible to drying out

Answer 13

lungs . . . invaginations

Question 14

While must the respiratory surface be wetted?

Answer 14

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

Question 14

What are evaginations?

Answer 14

Evagination refers to the outward folding or projection of a structure

Question 14

What is responsible for gas exchange? (think general)

Answer 14

the respiratory system is responsible for gas exchange

Question 14

What does the respiratory system consist of?

Answer 14

consists of all parts of the body involved in exchanging air between the external environment and the blood

Question 14

What is invagination?

Answer 14

Invagination refers to the inward folding or infolding of a structure.

Question 15

What do gills extend into for water-breathing animals?

Answer 15

in water-breathing animals, gills are evaginations of the body – they extend outward into the respiratory medium

Question 16

What is perfusion?

Answer 16

perfusion – the flow of blood or other body fluids to the internal side of the respiratory surface

Question 16

most animals have structures that ___ ___ ___ of the respiratory surface?

Answer 16

increase the area

Question 16

What three major things does the respiratory system contain in mammals?

Answer 16

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

Question 17

What 2 features help animals maintain the difference in concentration between gases outside and inside the respiratory surface, maximizing the rate of gas exchange?

Answer 17

Ventilation and perfusion

Question 17

What is ventilation?

Answer 17

ventilation – the flow of the respiratory medium (air or water) over the external side of the respiratory surface

Question 17

What are external gills?

Answer 17

external gills are gills that do not have protective coverings

extend out from the body, in direct contact with water

Question 18

in animals whose skin serves as the respiratory surface, the body is ____________________?

Answer 18

body is elongated or flattened

Question 19

What does the respiratory surface have in animals with gills?

Answer 19

in animals with gills, the respiratory surface has highly branched structures with many small projections

Question 19

Water vs air:
What takes more energy to move over respiratory surface?

Answer 19

it takes significantly more energy to move water than air over a respiratory surface

Question 19

What does the respiratory surface have in animals with lungs or tracheae?

Answer 19

in animals with lungs or tracheae, the respiratory surface has many branched tubes, folds, or pockets

Question 20

Water vs air:
What holds more O2?
What is O2 content affected by?

Answer 20

water holds less oxygen than air, and O2 content is affected by temperature and solutes

Question 21

What 3 properties of air reduce the energy required for ventilation?

Answer 21

relatively high O2 content, low density, and low viscosity of air greatly reduce the energy required for ventilation

Question 21

How do animals that live in water exchange gases?

Answer 21

most animals that live in water exchange gases through the skin or gills – aquatic mammals exchange gases through lungs

Question 21

What is the down side of an air medium?

Answer 21

however, animals lose water during breathing

Question 21

Water vs air:
Rate of diffusion of gas molecules?

Answer 21

gas molecules diffuse faster in air than in water

Question 21

Down side to external gills?

Answer 21

exposed to mechanical damage and must be immersed in water to keep them from collapsing or drying

Question 22

How do animals that live on land exchange gases?

Answer 22

most animals that live on land exchange gases through lungs – some exchange gases through gills, and others exchange gases using a tracheal system

Question 22

What are internal gills?

Answer 22

internal gills are located within a body chamber and have a cover that protects the gills from drying

Question 23

Down side of internal gills?

Answer 23

water must be brought to internal gills

Question 23

What environments have animals with external gills?
Examples?

Answer 23

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

Question 23

What do clams and oysters have to work cooperatively with gills?

Answer 23

clams and oysters use beating cilia to circulate water over their internal gills

Question 23

Where find animals with internal gills?

Answer 23

gills allow animals to live in diverse aquatic habitats and moist terrestrial habitats

Question 24

What do cuttlefish use cooperatively with gills?

Answer 24

cuttlefish use contractions of the muscular mantle to pump water over their gills

Question 25

What do body fish feature relative to their gills?

Answer 25

gills of bony fishes extend into a chamber covered by gill flaps or opercula, which help ventilate the gills

Question 25

What is countercurrent exchange?
How does this work?

Answer 25

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

Question 26

How do insects breathe?

Answer 26

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

Question 26

How much oxygen does counter current exchange remove from water?

Answer 26

countercurrent exchange removes 80-90% of water’s O2 content

Question 26

What gets air in and out of insects?

Answer 26

alternating compression and expansion of the body pumps air through the tracheal system

Question 27

How does air enter and leave the tracheal system of insects?
What are these structures called?

Answer 27

air enters and leaves the tracheal system at openings in the chitinous exoskeleton (spiracles), which open and close in coordination with body movements

Question 28

What is a secondary purpose of trachea?

Answer 28

at places within the body the tracheae expand into internal air sacs that act as air reservoirs

Question 28

Where are trachea and what do they connect in insects?

Answer 28

trachea lead from the body surface and branch extensively to almost every cell inside the animal

Question 28

What type of lungs do lungfishes and mature amphibians have?

Answer 28

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

Question 29

What are at the ends of trachea in insects?

Answer 29

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

Question 29

What adaptations allowed for animals to live in terrestrial environments?

Answer 29

lungs are one of the primary adaptations that allowed animals to live in terrestrial environments

Question 30

What does air flow throw in birds to gas exchange?

Answer 30

within the lungs, air flows through fine, parallel tubes (parabronchi)

Question 30

What is positive pressure breathing?

Answer 30

a gulping motion that forces air into the lungs

Question 30

How do reptiles and mammals fill their lungs?

Answer 30

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

Question 30

What is negative pressure breathing?

Answer 30

muscular contractions that expand the lungs, lowering the pressure and causing air to be pulled inward

Question 30

What do birds have in addition to lungs?

Answer 30

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

Question 31

What are the muscular structures of airway?

Answer 31

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

Question 31

What has the most efficient and complex lungs and what makes this possible?

Answer 31

in birds, a countercurrent exchange system provides the most complex and efficient vertebrate lungs

Question 32

What does the epithelium of bronchi contain?
Why?

Answer 32

the epithelium of bronchi contain cilia and mucus-secreting cells that trap bacteria and airborne particles and moves them upward into the throat

Question 32

What are parabronchi?
What do they allow for

Answer 32

parallel tubes that are surrounded by a capillary network – blood flows in the direction opposite to air flow (countercurrent exchange)

Question 32

What can tobacco smoke do to cilia in lungs?

Answer 32

tobacco smoke paralyzes the cilia

Question 32

What separates thoracic and abdominal cavity?

Answer 32

a dome-shaped sheet of skeletal muscle (the diaphragm) separates the chest cavity containing the lungs from the abdominal cavity

Question 33

What are the non-muscular airway structures?

Answer 33

the larynx, trachea, and larger bronchi are nonmuscular tubes encircled by rings of cartilage

Question 33

Seven structures that air moves through in humans?

Answer 33

1. nostrils and mouth
2. throat (pharynx)
3. “voice box” (larynx)
4. windpipe (trachea)
5. (bronchi)
6. (bronchioles)
7. (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

Question 34

How do lungs do exhalation?

Answer 34

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

Question 34

What muscles allow for inhalation?

Answer 34

contraction of the diaphragm and external intercostal muscles between the ribs brings air into the lungs by a negative pressure mechanism

Question 35

What are lungs covered by?
What does this allow for?

Answer 35

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

Question 35

What happens to exhalation when oxygen demand increases?

Answer 35

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

Question 36

What is tidal volume?

Answer 36

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

Question 37

What is vital capacity?

Answer 37

vital capacity is the maximum tidal volume of an individual
about 3,400 mL in females and 4,800 mL in males

Question 38

What is residual volume?

Answer 38

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

Question 39

What can higher brain centers do in breathing?

Answer 39

signals from higher brain centers in the cerebrum can override the respiratory controls of the brain stem

Question 39

What acts as the primary stimulator of inhalation at rest?

Answer 39

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

Question 39

What role does the pons have in breathing?

Answer 39

two interneuron groups in the pons modulate the signals from the medulla so that breathing is gradual and controlled

Question 39

Where is the rate and depth of breathing controlled?

Answer 39

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

Question 40

What else can breathing rate and depth be modified by?

Answer 40

breathing rate and depth are modified by emotional states – controlled by centers in the limbic system of the brain

Question 40

Where are 3 places chemoreceptors in body located to modulate breathing?

Answer 40

chemoreceptors are located centrally on the surface of the medulla, and peripherally in the carotid arteries (carotid bodies) and the aorta (aortic bodies)

Question 40

What must be true of PP for CO2 to diffuse outward across respiratory surface?

Answer 40

for CO2 to diffuse outward, its partial pressure must be greater inside than outside

Question 40

What do automated controls in the lungs do?

Reduced O2 concentration?

Increased O2 concentration?

Answer 40

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

Question 40

What sends signals for breathing during exercise?

Answer 40

during physical exercise, a ventral group of interneurons in the medulla sends signals for both inhalation and exhalation

Question 40

What must be true of PP for O2 to diffuse inward across respiratory surface?

Answer 40

for O2 to diffuse inward across a respiratory surface, its partial pressure must be greater outside than inside

Question 41

What do respiratory centers in the brain integrate sensory information from?

Answer 41

the respiratory centers in the brain integrate sensory information sent by chemoreceptors that monitor O2 and CO2 levels in the blood and body fluids

Question 41

What do receptors in medulla detect to modulate breathing?

Answer 41

receptors of the medulla detect pH changes in cerebrospinal fluid – determined mostly by CO2 concentration in the blood

Question 42

What is partial pressure?

Answer 42

when gases are present in a mixture, the pressure of each individual gas (its partial pressure) is determined by its proportion in the mixture

Question 42

What does CO2 and O2 diffuses between in lungs and why does this happen?

Answer 42

O2 and CO2 diffuse passively down partial pressure gradients between alveolar air and plasma in pulmonary capillaries

Question 42

Normal atmospheric pressure?

Answer 42

in dry air at sea level, the total atmospheric pressure under standard conditions is 760 mm Hg

Question 42

Where does CO2 produced by cellular oxidation diffuse to and what are the pressure of CO2 in these regions?

Answer 42

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)

Question 42

What percentage of O2 in blood in carried by what?

Answer 42

about 98.5% of the O2 in blood is carried by hemoglobin and about 1.5% is carried in solution in the blood plasma

Question 42

Where does O2 go after diffuse into blood plasma?

Answer 42

after entering the plasma, O2 diffuses into erythrocytes, where it combines with hemoglobin

Question 43

Partial pressure/percentage of O2 and CO2?

Answer 43

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

Question 43

What does hemoglobin contain?

Answer 43

hemoglobin has four heme groups, each containing an iron atom that can combine reversibly with an O2 molecule

Question 43

What does the top part of the hemoglobin-O2 dissociation curve show?

Answer 43

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

Question 43

What does the binding of O2 to hemoglobin cause?

Answer 43

combination with hemoglobin lowers the PO2 of the plasma and allows additional O2 molecules to diffuse into the blood

Question 43

What facilitates the reaction of CO2 into carbonic acid?

Answer 43

this reaction takes place both in blood plasma and erythrocytes, facilitated by the enzyme carbonic anhydrase

Question 44

What is the reversible combination of O2 and hemoglobin related to and shown by?

Answer 44

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

Question 44

What does the steep part of the hemoglobin-O2 dissociation curve show?

Answer 44

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

Question 44

What contributes to the release of O2 from hemoglobin?

Answer 44

several factors contribute to the release of O2 from hemoglobin, including increased acidity (lower pH)

Question 45

What is the P O2 and pH in lungs?

Answer 45

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.

Question 45

How does low pH in body tissues help?

What is the lower pH formed by?

Answer 45

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

Question 46

What happens to the majority of CO2? How much is this?

Answer 46

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

Question 47

What happens to the hydrogen ions produced by the dissociation of carbonic acid?

Answer 47

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

Question 48

Why is pH homeostasis important?

Answer 48

pH homeostasis is important because many enzymes are sensitive to minor changes in pH

Question 49

How does CO2 leave the body if it dissociates into carbonic acid?

Answer 49

as blood enters the capillary networks surrounding the alveoli, the process of CO2 uptake is reversed – CO2 diffuses from blood into the air

Question 50

What is CO?
What is it produced by?
Why is it harmful?

Answer 50

carbon monoxide (CO), a colorless gas produced when fuels are incompletely burned, binds so strongly to hemoglobin that it displaces O2

Question 51

What happens if CO is inhaled in high quantities?

Answer 51

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)

Question 52

Why can people die from CO poisonings without noticing?

Answer 52

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

Question 53

Study the study guide material for the respiratory system!

Question 54

Study the study guide material for animal nutrition!

Question 55

Study the study guide material from the case studies!