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BIO 203 > QUIZ 4 > Flashcards

QUIZ 4 Flashcards

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1
Q

cellular respiration

A
  • metabolism of glucose
  • anaerobic
  • aerobic
  • production of ATP
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2
Q

external respiration

A
  • the movement of gases (oxygen and carbon dioxide) between the external environment and the cells of the organism
  • coupled with cellular respiration
  • byproduct is water
  • CO2 waste product: exhale
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3
Q

external respiration pt. 2

A

-major function of external respiration is gas exchange
-uptake of molecular O2 from environment
-discharge of CO2 into environment
-another major function is acid-base balance:
CO2 + H2O = H2CO3 = H+ + HCO3-
-animals require continuous supply of O2
-environmental reservoirs of oxygen
-atmosphere is major reservior (about 21% O2)
-Bodies of water also contained dissolved O2
-O2 is not very soluble in water

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4
Q

cutaneous respiration: small or think animals

A
  • small or thin animals can use their body surface for gas exchange
  • ex. caenorhabditis elegans:
  • no respiratory or circulatory systems
  • O2 diffuses very slowly through water (about 3 million times slower than through air)
  • all cell must be close the respiratory surface
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5
Q

cutaneous respiration: large animals

A
  • the body surface does not have enough area to support all of the cells
  • specialized respiratory surfaces have evolved (gill, lung)
  • in many animals a closed circulatory system with one or more hearts serves as a transport medium between cells and a specialized respiratory system
  • however, not all animals with specialized respiratory surfaces transport O2 & CO2 via a closed circulatory system
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6
Q

aquatic animals

A
  • advantage of aqueous respiratory medium
  • respiratory surfaces stay moist
  • water not lost by evaporation
  • disadvantage of aqueous respiratory medium
  • O2 concentration relatively low
  • therefore, exchange must be very efficient
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7
Q

aquatic animal: gills

A
  • gills originate as evaginations (out foldings) of the body surface
  • in general, gills are organs that absorb dissolved O2 from an aqueous respiratory medium and excrete CO2
  • can be located all over the body (sea stars)- papulae are small but everywhere- high SA
  • can be restricted to a local body region (fish)
  • gas exchange at gills is maximized by:
  • large surface area
  • counter current exchange- increase extraction from environment
  • ventilation- increase water flow over gills
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8
Q

counter current exchange

A
  • partial pressure gradient (not concentration)
  • gases diffuse down their partial pressure gradients
  • concurrent exchange- blood flow and medium are flowing in the same direction, initially the pressure gradient is high and then gas transport averages out
  • countercurrent exchange- medium and blood flow are opposite, concentration gradient is maintained along the length of the exchange surface -> greater extraction of O2 -> higher pressure of O2 in the blood
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9
Q

aquatic animals: ventilation

A
  • ventilation- any method of increasing contact between the respiratory medium and the respiratory surface
  • usually requires expenditure of energy
  • ex. ciliated surface, paddle-like appendages to push water over gills (lobsters, crayfish), swimming- increased water flow over gills (fish) “ram-vetilation”
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10
Q

respiratory systems of echinoderms

A
  • sea stars have external papulae that function as gills for gas exchange (tiny envaginations in the dermal skeleton)
  • scattered over the body surface
  • projects outward through a hole in the dermal skeleton
  • cilia on the inner and outer surfaces beat in opposite directions, allowing counter current exchange of gases
  • water flows in through the madreporite ->
  • fluid in the coelom (body cavity) transports dissolved gases (water vascular system)
  • the tube feet of sea stars are also important site of gas exchange
  • movement is through hydrolic system
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11
Q

teleost fish

A
  • gills are anatomically localized in body surface
  • body cells are distant from the respiratory surface
  • large surface area for gas exchange
  • water flow across lamellae and blood is flowing in opposite direction (venules to arterioles)
  • ventilate by bulk flow of water over gills
  • closed circulatory system- allows gases to and from distant tissues
  • counter current exchange
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12
Q

coupled respiratory and circulatory systems

A
  • a strategy that has evolved in many animals is a 2 step exchange process involving a circulatory system
  • step 1- exchange between respiratory medium (air or water) and circulatory system (open, closed) (through diffusion)
  • step 2- exchange between circulatory system and interstitial fluid bathing cells (diffusion)
  • circulatory system transports gases to and from tissues throughout the body
  • allows for transport of gases to cells that are distant from the respiratory surface -> evolution of large animals
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13
Q

terrestrial animals

A
  • advantages of air medium:
  • much higher concentration of O2
  • O2 and CO2 diffuse faster in air
  • air is easier to move- ventilation requires less energy
  • disadvantage of air medium:
  • *loss of water by evaporation
  • respiratory surface may be folded into body
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14
Q

terrestrail chelicerates

A
  • spiders scorions (not insect)
  • book lungs composed of series of very thin tissue ‘plates’ (lamellae) and look like pages of a book (increase SA)
  • evolutionarily derived from book gills by ancestors
  • lamellae project into an air filled chamber inside body
  • air enters chamber by spiracle by diffusion
  • gas exchange occurs across the thin walls of the lamellae
  • oxygen enter hemolymph and is carried throughout the body in an open circulatory system
  • circulatory system for distribution of dissolved gases
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15
Q

tracheal system of insects

A
  • tracheal system has evolved that doesnt rely on circulatory system for O2 and CO2 exchange
  • air enters and exits through spiracles, which open to the exterior
  • finest branches are tracheoles, which are thin walled structures (.2 um)
  • tracheal tree
  • air filled tracheae branch extensively and carry air deep throughout animals body
  • end points of each branch are in direct contact with the bodys cells
  • ends of tracheoles are filled with hemolymph
  • hemolymph is used for gas exchange -> oxygen dissolved in the hemolymph before diffusing across the thin walls of the tracheoles and enter nearby cells (not distribution across body)
  • flight muscle tissue have high metabolic rates -> tracheoles extend into invaginations of the muscle cell membrane (small diffusion distance)
  • body movements compress the air sacs -> bulk flow
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16
Q

tracheal system limit the body size

A
  • largest insect now- atlas moth
  • largest insect- dragonfly like (griffinflies)- wingspan of 2.5 feet, extinct
  • diffusion of gases in the tracheal system limits body size
  • higher atmospheric O2 levels during the paleozoic may have allowed the evolution of larger insects
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17
Q

avian lungs

A
  • vertebrate lungs originate as invaginations of the body surface
  • in birds, system of air sacs allows unidirectional (one way) flow of air across the respiratory surface
  • lung is stiff/rigid and undergoes very little change in volume during the respiratory cycle -> lungs are not inflated during inspiration the same way in mammals
  • walls of the parabronchi have tiny blind-ended outpocketings called air capillaries that serve as the site of gas exchange
  • air capillaries have extremely thin walls and do not expand significantly during inspiration
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18
Q

mechanism of lung ventilation in birds

A
  • first inspiration- (expansion of chest) air bypasses the lung and enters posterior air sacs
  • first expiration- (compression of chest) air moves from posterior air sacs across the lungs respiratory surface
  • second inspiration- (expansion of chest) air moves from lungs to anterior air sac
  • second expiration- (compression of chest) air moves from anterior air sacs into the environment
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19
Q

cutaneous respiration: larger animals

A
  • some amphibians (frogs and salamanders) can exchange gases across their epidermis
  • some salamander do not have lungs or gills and rely on cutaneous respiration
  • gas exchange happens across the skin and epithelial layers of the mouth
  • these animals use cutaneous respiration and are large -> bc they have a closed circulatory system and the body cells are distant from respiratory surface
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20
Q

skin suffocation

A
  • myth
  • atmospheric oxygen is taken up by human skin but the contribution to total respiration is negligible
  • atmospheric oxygen supplies the epidermis and dermis to a depth of .25-.4 mm
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21
Q

mammalian respiration system

A
  • lung for gas exchange
  • localized respiratory surface
  • most body cells are distant from lungs (closed circulatory system)
  • nose/mouth -> trachea -> left/right primary bronchi (bronchus) -> bronchiole -> terminal bronchiole -> respiratory bronchiole -> aveolar duct -> aveolar sac -> aveolus (alveoli)
  • 24 divisions
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22
Q

diaphragm

A
  • main muscle of inspiration
  • ends are anchored to lower rib
  • central tendon is lowered during contraction of diaphragm muscle -> increases volume of thoracic cavity
  • mixed muscle- both fast and slow twitch fibers (good for rest and excerise)
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23
Q

mammalian lungs

A
  • mammalian lungs are anatomically localized and are not in direct contact with other parts of the body
  • gap between lungs and other organs/tissues is bridged by the circulatory system
  • dense network of capillaries associated with the lung epithelium
  • allows efficient transfer of gases between the circulatory system and the external environment
  • very short diffusion distance between air and blood
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24
Q

respiratory bronchiole

A
  • has a few aveoli associated with it

- little to none gas exchange here too bc of some aveoli presesnt on the bronchiole

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25
Q

aveoli

A
  • site of gas exchange
  • wall of aveoli are made of type 1 and 2 cells
  • type 2 - secrete surfactant- reduces surface tension
  • water is present in the aveolar chamber -> high surface tension -> surfacant reduces
  • limited interstitial fluid (short diffusion distance)
  • highly vascularized
  • aveolar macrophage- ingest foreign material
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26
Q

fused basement membrane

A
  • fused basement membranes- collagen & proteoglycans
  • endothelial cell and type 1 aveolar cell are sharing the fused basement membrane
  • not lipid bilayer
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27
Q

endothelial cells

A

-form capillaries

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28
Q

aveolar-capillary unit

A

-oxygen moves form alveolar air space -> across type 1 alveolar cell -> across fused basement membrane and endothelial cell -> to the plasma

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29
Q

conducting system

A
  • trachea
  • primary bronchi
  • smaller bronchi
  • bronchioles
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30
Q

exchange surface

A
  • respiratory bronchioles
  • alveoli
  • SA is very high
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31
Q

at the aveolar-capillary unit, a molecule of O2 traverses a total of _ phospholipid bilayer membranes while diffusing from the alveolar air space (lumen of alveolus) to plasma

A
  • 4
  • endothelial cell membrane twice
  • type 1 alveolar cell membrane twice
  • if the O2 was to cross through the nucleus of the capillary it would be 6
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32
Q

pleural sac

A
  • visceral pleural- up against lungs surface
  • porietal- up against the body cavity
  • in between is the pleural cavity filled with pleural fluid
  • double membrane surround the lung
  • elastic recoil
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33
Q

negative pressure in alveoloi

A
  • facilitates air coming in and out
  • outside pressure- 760
  • when diaphragm is pulled down the chest volume increases
  • elastic recoil creates inward pull
  • elastic recoil of chest wall outwards
  • opposing forces create negative pressure in pleural space relative to environment
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34
Q

external respiration

A
  • air flow depends of differences in pressure
  • air flow ~ pressure difference/ resistance to flow
  • pressure difference= alveolar pressure - atmospheric pressure
  • mammals exhibit negative pressure breathing
  • pressure difference is negative during inspiration
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35
Q

positive pressure breathing

A
  • air is mechanically forced into and out of the lungs
  • endotracheal tube
  • changes pressure gradient
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36
Q

negative pressure breathing

A
  • diaphragm is the major muscle of inspiration
  • during quiet breathing, inspiration is an active process (contraction of diaphragm) and expiration is a passive process (relaxation of diaphragm)
  • during forceful breathing (strenuous exercise) additional muscles are recruited for inspiration (external intercostals) and expiration (internal intercostals)
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37
Q

sternocleido mastoids and scalenes

A

-also work to raise the thoracic cavity and increase volume

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38
Q

intercostals

A
  • ribs muscles
  • used during forceful breathing (exercise)
  • inspiration and expiration
  • mixed muscle- 60% type 1 fiber
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39
Q

pneumothorax

A
  • if the sealed cavity is opened to the atmosphere, air flows in
  • the bond holding the lung to the chest wall is broken and the lung collapses
  • air in the thorax
  • elastic recoil causes collapse
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40
Q

surfactant reduced the work of breathing

A
  • surface active agents
  • a thin layer of fluid lines each alveolus
  • if this fluid layer is pure water a large amount of surface tension is generated due to the cohesive forces of water
  • *surface tension apposes lung inflation
  • complex mixture of proteins and phospholipids that disrupts cohesive forces of water and lowers the surface tension within alveoli
  • more concentration in smaller alveoli, which equalizes the pressure in small and large alveoli
  • surfactant is secreted by type 2 alveolar cells
  • *reduces surface tension
  • *equalized the pressure
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41
Q

small alveoli

A
  • smaller alveoli more pressure -> more surfactant is needed
  • P=2T/r
  • equalized pressure
  • reduced surface tension
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42
Q

surfactant example

A

-aveoli 1- small
-aveoli 2- large
NO SURFACTANT
-if alveoli 1 and alveoli 2 have equal surface tension
-alveolus 1 has higher pressure than 2
-alveolus 1 is likely to collapse as air moves to alveolus 2 (high pressure to low)
SURFACTANT
-alveolus 1 has less surface tension due to more surfactant per unit surface area
-alveoli 1 and 2 have equal pressure

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43
Q

premature human babies

A
  • lung may be under developed
  • inadequate surfactant concentrations
  • newborn respiratory distress syndrome- was once leading cause of infant death
  • corticosteroids given to the mother can accelerate the development of the fetal lung
  • artificial surfactants are available
  • positive pressure breathing (mechanical ventilation)
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44
Q

spirometry

A
  • measuring ventilation extension of lung function
  • bell moves up and down in water
  • as you breathe in bell goes down vice versa
  • pulley system
  • positive inflection- inspiration
  • negative deflection- expiration
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45
Q

tidal volume

A
  • 500ml
  • what you normally breathe in and out
  • the volume of air moved in and out of the lungs during normal quiet breathing
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46
Q

expiratory reserve volume

A
  • additional volume of air that can be expired from lungs by forceful effort following normal expiration
  • 1100 ml
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47
Q

residual volume

A
  • even when you forcefully breathe out there is still air in your lungs
  • vol of air remaining in lungs at the end of a forced exhale
  • this is bc there are cartilaginous rings that cant be compressed
  • 1200ml
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48
Q

inspiratory reserve volume

A
  • max volumeof additional air that can be drawn into the lungs by a forceful effort following a normal inspirations
  • inhaling forcefully
  • 3000ml
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49
Q

vital capacity

A
  • the maximum effort
  • maximal inhale and maximal exhale
  • capacity- sum of one or more volumes
  • tidal vol + inspiratory reserve vol + expiratory reserve vol
  • 4600 ml
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50
Q

total lung capacity

A
  • maximum inhale (inspiratory reserve vol)
  • maximum exhale (expiratory reserve vol)
  • plus the residual volume
  • plus tidal volume
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51
Q

emphazema

A
  • destruction of alveoli
  • lung is less compliant
  • total lung capacity increases
  • hard time expiring air
  • residual vol increases
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52
Q

lung fibrosis

A
  • fibrotic tissue destruction
  • difficult to inflate
  • total lung capacity decreases
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53
Q

dead space

A
  • technically not a lung volume or capacity
  • volume of air remaining in airways at the end of each exhalation
  • 150 ml
  • a consequence of bi-directional flow through airways
  • mixes with fresh air during inhalation
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54
Q

alveolar ventilation

A
  • volume of fresh air reaching alveoli per min: (volume of fresh air per breath reaching alveoli) x (number of breaths per min)
  • need to consider effect of dead space: (vol of fresh air per breath reaching alveoli) = (breath vol - dead space)
  • ex. consider an adult breathing with normal tidal vol (500 ml) at 12 breath per min. ->
  • total pumonary ventilation- 500ml/breath x 12 breath/min = 6L/min
  • alveolar ventilation- 500-150ml/breath x 12 breaths/min = 4.2 L/min
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55
Q

increasing breath volume

A

more effective at increasing alveolar ventilation

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56
Q

ventilation

A
  • bulk flow
  • no atp
  • no carrier proteins
  • main stimulus for regulation ventilation is CO2
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57
Q

overview of O2 and Co2 exchange and transport

A

-high partial pressure of O2 in alveoli -> moves from alveoli into circulatory system -> pumped systemically-> low partial pressure of O2 in tissues -> O2 moves into tissues -> acts as final electron acceptor for aerobic respiration -> CO2 product -> low partial pressure in circulatory system -> moves into circulatory system -> majority of CO2 is transported as HCO3- -> moves into pulmonary circulation which has high partial pressure of CO2 -> CO2 moves into alveoli -> expired

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58
Q

partial pressure of a gas

A
  • in a mixture of gases (atmosphere), the amount of pressure due to a specific gas is the partial pressure of that gas
  • difference in partial pressure is the driving force for diffusion of gas
  • gases diffuse from a region of high partial pressure to low
  • ex. @ sea level air pressure is 760 and air is 21% O2 -> .21 x 760 = 160 partial pressure O2
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59
Q

gases in solution

A

-at equilibrium partial pressure is equal but concentration is not

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60
Q

ficks law of diffusion

A
  • diffusion of gases (O2 and CO2) between lung and blood (or between blood and cells) obey ficks law of diffusion
  • dQ/dt =D * (P2-P1)
  • D- diffusion coefficient- directly proportional to surface area and inversely proportional to diffusion distance
  • (P2-P1)- pressure gradient of gas is the driving force of diffusion
  • usually, factors determining D are constant -> the most important factor is the pressure gradient (driving force)
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61
Q

O2 and CO2 partial pressures

A
  • Atm- PO2 160, PCO2 .25
  • alveoli- PO2 100, PCO2 40
  • arterial blood- PO2 100, PCO2 40
  • cells- PO2 < 40, PCO2 > 46 (diff tissues have diff levels of metabolic rate at diff times)
  • venous blood- PO2 < 40, PCO2 > 46
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62
Q

partial pressure from alveoli to arterial blood

A

same because of bulk flow

-there is no diffusion across the walls of the heart chambers

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63
Q

oxygen transport

A
  • oxygen is not very soluble in aqueous solutions
  • little dissolved O2 even when partial pressure of O2 is high
  • oxygen is carried by respiratory pigments: hemocyanins and hemoglobin
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64
Q

hemocyanins

A
  • copper binds oxygen (arthropods, molluscs)
  • arthropods: 3 protein subunits
  • mulluscs: 2 protein subunits
  • blue domains each have 2 copper atoms; each copper atom is coordinated by three histidine (HIS) residues
  • one oxygen per heomcyanin
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65
Q

hemoglobin

A
  • iron-containing heme group (protoporphyrin IX) binds oxygen
  • 98% of the O2 content of blood carried by hemoglobin in humans
  • four protein subunits (4 polypeptide chains: 2 alpha and 2 beta in adults)
  • each subunit contains one heme group
  • one iron atom at the center of each heme group binds one O2 molecules -> 4 O2 for one hemoglobin
  • coordinate covalent bond between the oxygen and iron (electron pair coming from O2) -> very reversible
  • binding at the lung is favored due to high partial pressure of O2 at lung
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66
Q

heme group

A
  • prosthetic group
  • ring structure
  • stable
  • porphyrin ring
  • iron bonds to oxygen
  • 4 heme groups per hemoglobin -> 4 oxygen
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67
Q

red blood cell

A
  • lack of organelles
  • biconcave structure
  • cytoskeleton in the plasma membrane -> anchored protein interactions here generate the force that give it shape
  • advantages of the biconcave structure:
  • most hemoglobin is positioned close to the cell membrane, reducing the diffusion distance of O2
  • allows the RBC to bend and twist while negotiating tight passages in the capillaries
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68
Q

bird RBC

A
  • football shape
  • birds are optimized to extract oxygen from air
  • explains football shape
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69
Q

sick cell disease

A
  • become hydrophobic
  • tends to polymerize and form chains
  • aggregates that precipitate and deform shape into crescent
  • can obstruct blood flow in small vessels
  • clogs
  • mutation is not in heme group
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70
Q

oxygen transport in blood

A
  • oxygen enters the circulatory system from the alveoli by diffusing down its concentration gradient
  • 2% is dissolved in plasma and 98% binds to hemoglobin in RBC
  • Hb is transported through tissues
  • partial pressure gradient favors dissociation of O2 into tissues (coordinated covalent bond broken)
  • O2 acts as the final electron acceptor in aerobic respiration
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71
Q

hydrogen ions affect the conformation of hemoglobin

A
  • decreased binding affinity of O2 to hemoglobin
  • pH decreases in very active tissue due to high PCO2
  • increased release of O2 from hemoglobin in capillary beds of active tissues
  • other factors can also cause a rightward shift in the HbO2 curve:
  • increase in temp
  • high PCO2
  • 2,3 bisphosphoglycerate
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72
Q

Bohrs shift

A
  • hemoglobin O2 dissociation curve is shifted
  • as you run around you generate CO2 and H+ concentration and 2,3 bisphosphoglycerate
  • H+ ions bind to hemoglobin causing the right ward shift
  • @ rest PO2 P50 is 27 mmHg
  • hemoglobin has lower affinity for O2 (gives of O2 easy) when you are active
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73
Q

myoglobin

A
  • respiratory pigment in muscle
  • monomer
  • concentration highest in muscles that rely on aerobic metabolism (red muscle, dark meat)
  • has a single polypeptide chain and one heme group
  • one porphyrin ring
  • can bind one O2 (hand-off)
  • much higher affinity for O2 than Hb
  • more than 80% saturated at a PO2 of 20 mm Hg (a point where hemoglobin has given up most of its O2)
  • O2 reserve in muscles
  • leftward shift for P50 value -> higher affinity
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74
Q

maternal and fetal hemoglobin have different O2 binding properties

A

-fetal hemoglobin has a higher affinity for O2 than maternal

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75
Q

smaller P50

A

high affinity for O2

76
Q

cooperativity in oxygen binding hemoglobin

A
  • hemoglobin curve is sigmoidal
  • binding of O2 in Hb causes a conformational change
  • conformational change causes causes subsequent O2 molecules bind with higher affinity
  • cooperativity in O2 binding -> sigmoidal shape of the Hb-O2 curve
  • vice versa with unbinding!
77
Q

CO2 transport in the blood

A
  • CO2 is soluble in water (and blood plasma)
  • 7% is dissolved
  • 23% bound to amino groups (Hb)
  • 70% bicarbonate buffer system
78
Q

bicarbonate buffer system

A

CO2 + H2O ->

79
Q

CO2 transport in blood

A
  • high partial pressure of CO2 in tissue
  • 7% dissolves into plasma
  • most is transported at bicarbonate in RBC
  • bicarbonate then moves out of the RBC in exchange for Cl- moving in
  • bicarbonate is in the circulatory system and goes to the lungs
  • reverse bicarbonate reaction occurs producing CO2
  • low partial pressure in alveoli causes CO2 to diffuse in
80
Q

Bohr shift refers specifically to phenomenon where the binding affinity of Hb for O2 decreases in metabolically active tissue with elevated pH

A
  • false

- everything is true except it is low pH not elevated

81
Q

respiratory drive

A
  • physiological drive to breath
  • some voluntary some involuntary
  • some factors that affect the rate and depth of breathing:
  • PCO2, PO2, pH
  • emotions
  • sleep
  • lung inflation
  • speech
  • conscious volition
82
Q

control of ventilation

A

-high partial pressure of CO2 in plasma
-CO2 diffuses across blood brain barrier (H+ cannot)
-carbonic anhydrase combines CO2 with water and forms carbonic acid which dissociates into bicarbonate and H+
-central chemoreceptor senses the H+ ion binding -> increases sodium influx -> depolarization -> action potential -> activation of somatic motor neurons -> increase ventilation, increase contraction of diaphragm and external intercostal muscles
increased ventilation increases PO2 and decreases plasma PCO2
-negative feedback

83
Q

medulla & pons

A
  • central pattern generator for breathing
  • neurons in the medulla that fire spontaneously
  • generate the rhythm of breathing
  • similar to SA node mechanism except it innervates skeletal muscle (diaphragm)
  • integrate information
  • changes the firing rate of somatic efferent neurons that innervate inspiration and expiration muscles
84
Q

cerebral cortex

A
  • deciding consciously how to breathe

- deciding to hold your breathe

85
Q

peripheral chemoreceptors and central chemoreceptors

A
  • responding to CO2
  • specific stimulus is H+ ions
  • carotid and aortic chemoreceptors
  • O2 and pH can regulate but only under extreme low PO2 plasma levels
86
Q

hyperventilation

A
  • increases the partial pressure of O2 in alveoli
  • no increase in blood content of O2
  • this is because even at 100 mm Hg hemoglobin is already saturated
  • blows off more CO2 (less available)-> bicarbonate equation is in reverse:
  • increases pH of CSF
  • decrease H+
  • decreases respiratory drive
87
Q

hypoventilation

A
  • increase plasma PCO2
  • decreases pH of CSF
  • increases respiratory drive
88
Q

hyperventilation increase the pH of CSF and decreases the pH of plasma

A
  • false
  • it does increase the pH of CSF
  • plasma and CSF are parallel
  • they both increase
89
Q

asthma

A
  • very common
  • exaggerated immune response to trigger
  • inflammed airways
  • excess mucus
  • contraction of smooth muscle in the airways
  • reduces airway caliber
  • difficulty exhaling
  • relaxation of the diaphragm is not sufficient
  • there are many triggers
  • maintenance medication- regular basis, drug is delivered directly to airways (includes fluticasone, a steriod, similar to cortisol)
  • rescue medication- quickly relaxes airway muscles
90
Q

Beta 2 adrenergic agonists

A
  • inhaled, short acting: albuterol, bitolterol, terbutaline
  • inhaled, long acting: salmeterol, formoterol
  • based upon endogenous hormone norepinephrine (bind to the same receptor)
  • agonist binds to beta 2 adrenergic receptor -> acts on adenylate cyclase -> produce cAMP -> activates PKA -> airways smooth muscle relaxation -> airways caliber increases
91
Q

there are 24 airway branches

A
  • false
  • there are hundred of millions
  • there are 24 divisions
92
Q

external intercostal muscles participate in expiration

A

false

93
Q

inspiratory reserve volume is greater than expiratory reserve volume

A

true

94
Q

Functions of the mammalian kidney

A
  • regulation of ECF volume and blood pressure
  • filtration -> 99% of it is reabsorbed
  • regulation of osmolarity (inorganic ion balance: Na, K)
  • Elimination of metabolic waste products (urea, uric acid, creatinine)
  • removal of foreign chemicals (pesticides, drugs, foods, additives)
  • gluconeogenesis (during periods of prolonged fasting)
  • secretion of hormones and an enzyme:
  • erythropoietin (stimulates RBC production)
  • 1,25-dihydroxyvitamin D3 (important for Ca homeostasis)
  • *renin (an enzyme that generates the precursor of angiotensin 2, which influences Na and K homeostasis and blood pressure
95
Q

reabsorption

A
  • there is no primary active transport for water
  • > they reabsorb solutes (Na)
  • diffusion
96
Q

ureter

A

where the urine exits the kidney to the bladder

97
Q

urinary bladder

A
  • smooth muscle

- expands

98
Q

anatomy of the kidney

A

-cross section- kidney is divided into an outer cortex and an inner cortex
-urine leaving the nephrons flows into the renal pelvis prior to passing through the ureter into the bladder
-outer capsule surrounds
-under capsule is cortex
-under cortex is medulla
-1 million nephrons per kidney
-

99
Q

nephrons

A
  • functional unit of the kidney
  • filters blood
  • two arterioles and two sets of capillaries = portal system
100
Q

medulla

A
  • contain arcuate arteries and veins
  • arcuate arteries arch into the afferent arterioles
  • afferent arterioles lead into the glomerulus (millions)
  • leaves the glomerulus by efferent arterioles
  • drained by arcuate vein
101
Q

glomerulus

A
  • each one is a ball of capillaries
  • site of blood filtration
  • enters the glomerulus through afferent arteriole
102
Q

cortical nephron

A
  • shorter loop of henle
  • many peritubular capillaries associated (a lot of exchange between blood and nephron) -> allows exchange
  • shorter -> less water reabsorption -> less concentrated urine
103
Q

juxtamedullary nephron

A
  • long loop of henle
  • many peritubular capillaries associated (a lot of exchange between blood and nephron) -> allows exchange
  • vasa recta- longer peritubular -> more change for exchange
  • bc its longer more water can be absorbed -> more concentrated urine
104
Q

vasa recta

A
  • in the juxtamedullary nephron
  • longer peritubular capillary
  • allows for more chance of exchange
  • much more water reabsorption here
  • water reabsorption happens descending in loop of henle
105
Q

collecting duct

A
  • regulation of water reabsorption

- many nephrons will merge and move into one collecting duct

106
Q

bowmans capsule

A
  • collects filtrate

- first part of the nephron

107
Q

anatomy of nephron

A
  • starts with bowmans capsule (glomerulus is here)
  • goes to the proximal tubule
  • down to the descending limb
  • bottom is called loop of henle
  • goes up the ascending limb
  • reaches the distal tubule
  • lastly, goes to collecting duct
  • ureter -> bladder
108
Q

function of the nephron

A
  • filtration
  • reabsorption
  • secretion
  • excretion (urine)
109
Q

filtration

A
  • site of blood filtration- glomerulus
  • podocytes surround capillaries- foot processes
  • hydrostatic pressure in capillaries forms ultrafiltrate
  • ultrafiltrate move through endothelium into bowmans capsule
  • mesangial cell- phagocytes that prevent clogging of proteins
110
Q

glomerular capillary: 3 layer filtration barrier

A
  1. endothelium- has fenestration (pores)- large particles cant move through
  2. basement membrane- extracellular matrix -> collagen/proteoglycans
  3. podocytes- foot processes -> slit diaphragm- complex of proteins
111
Q

ultrafiltrate

A

size selective

-180 L form a day

112
Q

driving force

A
  • hydrostatic pressure (blood pressure within glomerular capillaries)
  • colloid osmotic pressure due to proteins in plasma but not in bowmans capsule
  • fluid pressure due to fluid in bowmans capsule
  • hydrostatic pressure - colloid osmotic pressure - fluid pressure = net filtration pressure
113
Q

afferent arteriole

A
  • primary site of regulation -> glomerular filtration rate (GFR)
  • surrounded by smooth muscle that can vasoconstrict/dilate
  • constriction -> increase in resistance, decrease flow, decrease hydrostatic pressure, decrease GFR
  • dilation- decrease resistance, increase flow, increase pressure, increase GFR
114
Q

autoregulatory (intrinsic) control

A
  • myogenic response

- tubuloglomerular feedback

115
Q

extrinsic control

A

-neural and hormonal regulation of afferent arteriolar diameter

116
Q

myogenic response: intrinsic

A
  • blood pressure can vary dramatically
  • GFR remains constant between 80-180 BP
  • normal MAP = 93
  • increased pressure -> smooth muscle vessel walls stretch
  • mechanosensitive ion channels (Na) in the arteriole wall activate
  • depolarization -> Ca release -> contraction of vascular smooth muscle cells (vasoconstriction) -> decrease blood flow -> decrease in pressure
117
Q

MAP

A

-CO x system vascular resistance=MAP

118
Q

tubuloglomerular feedback: intrinsic

A
  • nephron wraps around on itself
  • ascending limb of loop of henle senses fluid flow (macula densa cells are here)
  • an increase in filtration -> increase in ultrafiltrate -> increase if GFR -> macula densa cells sense increased flow -> paracrine factors are released (adenosine) from macula densa -> afferent arteriole vasocostriction -> decrease in hydrostatic pressure -> decrease in GFR
119
Q

neural and hormonal regulation of afferent arteriolar diameter: extrinsic

A
  • most occurs via afferent arteriole
  • smooth muscle cells of the afferent arterioles have alpha 1 receptors for norepinephrine to vasoconstrict
    1. neural
  • sympathetic neurons innervate the afferent arteriole and release norepinephrine
  • afferent vascular smooth muscle cells have alpha-adrenergic receptors that mediate vasoconstriction in response to norepinephrine
  • fight or flight response -> constrict -> blood flows to other organs in need (hemorrhage)
  • significant blood loss
    2. hormonal
  • many hormones like angiotensin 2 is a vasoconstrictor that reduces GFR
120
Q

vasoconstriction of the efferent artiole (afferent remains unchanged) would increase hydrostatic pressure in the glomerular capillaries and increase glomerular filtration rate (GFR)

A
  • true
  • exit is reduced
  • pressure is still increased in the glomerular capillaries
  • same amount of blood coming in and less coming out -> increase pressure
  • filtration increases therefore
121
Q

filtration fraction

A
  • 100% of blood volume in afferent arteriole (not 100% CO)
  • 80% passes through glomerulus and bowmans capsule (20% is filtered)
  • of that 20% more than 19% is reabsorbed
  • less than 1% is excreted as urine
122
Q

reabsorption of water

A
  • solutes are reabsorbed
  • mostly Na (also anions, K, Ca, urea) bc it is the main determinant in ECF volume
  • solutes move from the tubule lumen past the tubular epithelium and into the extracellular fluid
  • water follows solute through aquaporins
  • solutes use a variety of primary and secondary active transport
123
Q

passive transport

A
  • urea
  • ultrafiltrate forms
  • solutes are being transported and water is following
  • this leads to concentrated urea bc water is being reabsorbed
  • this results in a concentration gradient for urea and its able to diffuse passively into the fenestrated peritubular capillary
124
Q

sodium reabsorption

A
  • active transport
  • Na/k atpase pump
  • moving against gradients
  • on the basolateral surface there is active transport of Na and K pump
  • on apical surface (tubule lumen side) there are open channels that move Na down concentration gradient (created by atpase pump) with glucose against its concentration gradient -> secondary transport
125
Q

glucose: secondary active transport

A
  • Na gradient created on apical surface allows for Na to diffuse down its concentration gradient
  • brings glucose with it against its concentration gradient
  • uses SGLT protein (antiporter)
  • glucose then diffuses across the basolateral surface using GLUT protein (facilitated diffusion)
  • secondary active transport
126
Q

renal secretion

A
  • secreted into the lumen
  • enhances excretion capability
  • active process
  • secretion of K and H+ important for hemostatic regulation
  • several organic compounds (penicilin) are secreted
127
Q

renal excretion

A
  • a measure of overall kidney function
  • can be measured in a non-invasive way (clearance)
  • renal clearance can be used to assess kidney function
  • summation of what gets filtered reabsorbed and secreted
128
Q

3 pathways

A
  • penicillin- secretion > filtration
  • Na, H20, urea- reabsorption > secretion
  • glucose, amino acids- all is filtered and reabsorption (no secretion)
129
Q

penicillin

A
  • most is secreted
  • treats bacterial resistance
  • probenicid- blocks secretion through competitive mechanisms
130
Q

glucose filtration

A
  • no secretion, all reabsorbed
  • freely filtered
  • small organic molecule
  • filtration of glucose is proportional to plasma concentration
  • filtration does not saturate
  • as you increase plasma glucose level filtration rate of glucose increases infinitely
131
Q

glucose reabsorption

A
  • reabsorption of glucose is proportional to plasma concentration until transport maximum (Tm) is reached
  • Tm= 375 mg/min
  • transporter is saturable
132
Q

glucose excretion

A
  • excretion = filtration - resorption
  • normally excretion is zero
  • at renal threshold is starts to increase
  • renal threshold = 300 mg/100 mL plasma
  • diabetic have glucose in urine
133
Q

type 1 diabetes mellitus

A
  • autoimmune disease: destruction of beta cells in pancreas
  • insulin hyposecretion (formerly called insulin dependent diabetes mellitus)
  • hyperglycemia: significantly elevated plasma glucose
  • glucosuria: glucose in urine
  • damage to blood vessels, eyes, kidneys, CNS
  • polyuria: excessive urine production- osmotic diuresis
  • polydipsia- excessive thirst
  • polyphagia- excessive hunger
134
Q

type 2 diabetes mellitus

A
  • formerly called non-insulin dependent diabetes
  • thought to be principally a disease caused by lifestyle factors (being overweight and sedentary)
  • 97% of all diabetics are type 2
  • common hallmark is insulin resistance, particulary in muscle and adipose tissue
  • glucose tolerance test- cannot differentiate between problems with insulin secretion, synthesis or end-organ responsivity
  • hyperglycermia
  • most effective treatments combine weight reduction and exercise
  • atherosclerosis, renal failure, blindness, neurological damage
  • 70% die from cardiovascular disease
135
Q

following consumption of spaghetti, blood glucose levels in a diabetic may peak at 200 mg/dl or higher, because renal filtration of glucose saturates

A
  • false
  • reabsorption is saturating
  • filtration cant saturate
136
Q

glycated hemoglobin

A
  • HbA1c assesses glucose load
  • long term indication of blood glucose levels
  • HbA1c becomes modified covalently with glucose
  • degree of modification depends upon glucose load
  • hemoglobins half life is long (2 months) so we can see changes over time
  • blood glucose 90 -> HbA1c 5%
  • blood glucose 360 -> HbA1c 14%
137
Q

transporters

A
  • move glucose into circulation

- SGLT1 and SGLT2

138
Q

SGLT1

A
  • mostly in small intestine, some in kidney and heart
  • late proximal straight tubule
  • high affinity for glucose
  • low capacity for glucose transport
  • 10% of renal glucose reabsorption
139
Q

SGLT2

A
  • almost exclusively in kidney
  • early proximal convoluted tubule
  • low affinity for glucose
  • high capacity for glucose transport
  • 90% of renal glucose reabsorption
  • drug target bc low affinity and high capacity and not expressed elsewhere, accounts for a lot
  • canagliflozin- drug that blocks SGLT2 reabsorption
  • problem is that glucose is going in the urinary tract -> UTIs
140
Q

amount of soloute excreted

A

= amount filtered - amount reabsorbed + amount secreted

141
Q

renal clearance

A
  • method of quantifying renal function
  • non-invasive diagnostic procedure to measure GFR
  • defined as the volume of blood plasma that was cleared of a substance has been completely removed (cleared) per unit of time
  • volume/time (mL/min)
  • clearance is a rate
  • ex. glucose is normally 0 anything above is abnormal
  • a substance that is freely filtered, but NOT reabsorbed and NOT secreted would be ideal to determine clearance -> inulin
  • if filtration and excretion are the same, there is no net reabsorption or secretion, and the clearance of a substance equals GFR
142
Q

inulin

A
  • plant carbohydrate
  • exogenous
  • ideal properties -> freely filtered and not reabsorbed or secreted
  • humans do not have transporters for this -> injection
143
Q

example of inulin clearance

A
  • 100ml of plasma and 4 molecules of inulin
  • inulin is freely filtered and hydrophilic
  • inulin is trapped in lumen (no transporters for inulin)
  • 0% reabsorption and 0% secretion
  • plasma is being reabsorbed and secreted
  • 100% inulin excreted -> inulin clearance 100mL/min
  • GFR= 100mL/min
  • inulin clearance = GFR (no secretion or reabsorption)
144
Q

example of glucose clearance

A
  • soluble, freely filtered
  • 100mL of plasma
  • glucose is 100% reabsorbed bc of glucose transporters (simporter, facilitative transporter)
  • clearance rate is 0
  • 0% glucose excreted
  • Cinulin > Curea
145
Q

example of urea clearance

A
  • net resorption
  • filtration > excretion
  • 100mL plasma, 4/100mL plasma concentration
  • freely filtered
  • 50% of urea is reabsorbed, 50% urea excreted
  • 50mL/min urea clearance
  • Cinulin > C urea
  • 2 urea/min excreted
146
Q

net secretion

A

-if clearance of a substance is greater than GFR -> net secretion

147
Q

example of penicillin clearance

A
  • excretion > filtration -> net secretion
  • 100mL of plasma
  • 4/100mL plasma concentration
  • freely filtered
  • penicillin is actively secreted from the peritubular capillaries into the proximal tubule of the nephron -> more penicillin excreted than was filtered -> 6pinicillin/min
  • plasma reabsorbed, 0% penicillin reabsorbed
  • penicillin clearance= 150 mL/min
  • Cinulin
148
Q

real world example of clearance

A
  • inject precise drug dose into rat tail vein
  • collect urine 10mL of urine over 10 hours
  • concentration of drug in urine = 1 mg/ml
  • rate of appearance of drug in urine = (10mL x 1 mg/ml)/10 hour = 1 mg/hour -> excretion rate
  • clearance = (rate of appearance of drug in urine)/(plasma concentration of drug)
  • measured plasma concentration = 1mg/mL
  • clearance = (excretion rate)/(plasma concentration of drug) = 1 mg/ml
149
Q

clearance=

A

excretion rate/plasma concentration of drug
-excretion rate= rate of appearance of drug in urine = (volume of urine collected x concentration of drug in urine)/collection time

150
Q

important generalization about clearance

A
  1. Cinulin = GFR (ml/min)
  2. If Csubstance > Cinulin, then substance is filtered and secreted (on a net basis)
  3. If Csubstance = Cinulin. then substance X is filtered, not secreted and not reabsorbed (on a net basis)
  4. If Csubstance < Cinulin, then substance X is filtered, secreted and reabsorbed (on a net basis)
  5. creatinine is the closest naturally occurring substance with clearance values approx those of inulin
  6. Ccreatine (about)= GFR = Cinulin
151
Q

units for clearance are mL/min, and the mL refers to volume of urine collected

A
  • false

- mL= vol of blood plasma

152
Q

physiological regulation of H2O, Na, and K

A
  1. Na reabsorption is an active process
  2. H2O reabsorption is by osmosis (diffusion) and will follow Na reabsorption (when possible)
  3. Na reabsorption and H2O reabsorption are independently regulated
    - regulatory systems:
    - arginine vasopressin (AVP) / Antidiuretic hormone (ADH)
    - renin-angiotensin aldosterone system (RAAS)
    - natriuretic peptides
153
Q

decrease in blood volume and blood pressure

A
  • volume receptors in the atria and carotid and aortic baroreceptors detect (stress receptors) -> trigger hemostatic reflexes
  • decrease firing rate decrease stretch -> less activation of inhibitory interneurons -> less negative input to sympathetic neurons -> increase rate of release of norepinephrine ->
  • norepinephrine acts on the heart (SA node) -> increase heart rate/contraction through beta 1 receptors -> increase CO -> act on alpha receptors -> vasoconstriction -> increase resistance -> increase MAP
  • behaviorally -> drink water -> increase ECF & ICF volume -> increase BP
  • kidney hormones work to conserve water
154
Q

decrease in blood volume and blood pressure

A

volume receptors in atria, endocrine in atria, and carotid and aortic baroreceptors

  • muscles are stretched
  • release peptide hormones atriorectic factor
  • inhibit release of renin
155
Q

kidneys conserve volume

A
  • kidneys return water to the circulatory system
  • consume more water -> excrete more water -> less being returned
  • proximal tubule isosmotic to plasma -> as it goes down loop of henle water is reabsorbed through aquaporins (interstitial vol is hyperosmotic) -> as it ascends ions reabsorbed (no aquaporins are here)
  • in distal tubule and collecting duct water reabsorption is primary regulated by vassopresin
  • 50-1200 mOsM urine is excreted
156
Q

vasopressin (AVP)

A
  • controls the trafficking of vesicles that contain aquaporin channels
  • vasopressin is controlling the permeability by controlling the trafficking of aquaporins at the apical surface @ collecting ducts
  • made in the hypothalamus -> nerve cell body synthesize AVP
  • hormone is packaged in vesicles and transported down axon and stored and await for release in posterior pituitary (NOT bound by carrier protein)
  • released into the blood
  • increase is plasma osmolarity signals the release of AVP
157
Q

H2O movement

A
  • can only occur if epithelial cell membranes are permeable to H2O (if aquaporin channels are present)
  • H2O permeability is high in the proximal and distal tubules and is reabsorbed by osmosis in constant proportions following reabsorption of solutes
  • H2O permeability is high in the descending loop of henle and essentially zero in the ascending
  • H2O permeability in the collecting duct can be high or low and is regulated by vasopressin
158
Q

Na and H2O reabsorption

A
  • sodium is actively reabsorbed and water follows Na by osmosis
  • Na actively transported on basolateral membrane
  • gradient formed allows Na to diffuse passively in the apical surface
  • if aquaporins are present in apical surface it can move past due to Na gradient
  • vasopressin is controlling the permeability by controlling the trafficking of aquaporins in collecting ducts (apical surface)
  • The movement of Na+ from the interstitial space surrounding the proximal tubule cells into the peritubular capillary blood does not require active transport
159
Q

bulk flow

A

-water moves into the peritubular capillaries by bulk flow

160
Q

triggers for vasopressin (AVP)

A
  1. decreased blood pressure -> sensed by carotid and aortic baroreceptors -> sensory neuron to hypothalamus -> hypothalamic neurons synthesize AVP
  2. decreased atrial stretch due to low blood volume -> sensed by atrial stretch receptor -> sensory neuron to hypothalamus -> hypothalamic neurons synthesize AVP
  3. osmolarity greater than 280 mOsM -> sensed by osmoreceptors in the hypothalamus -> interneurons lead to hypothalamus neurons that synthesize AVP
161
Q

regulation of vasopressin

A
  • hypothalamic neurons synthesize AVP
  • vasopressin (AVP) released from posterior pituitary
  • affects collecting duct epithelium
  • *insertion of water pores in apical membrane
  • increased water reabsorption to conserve water
162
Q

insertion of aquaporin water channels in apical membrane

A
  • vasopressin binds to cell surface receptor (g-protein coupled) on basolateral membrane
  • cAMP released and activates PKA -> phosphorylates substrates (aquaporin-2 water channel subunits) -> exocytosis of vesicles containing aquaporins at apical surface
  • aquaporin-2 responds to vasopressin
163
Q

max vasopressin

A
  • collecting duct is freely permeable to water
  • water leaves by osmosis and is carried away by vasa recta capillaries
  • reabsorption
  • urine will be concentrated
164
Q

diabetes insipidus

A
  • loss of ability to produce AVP (central diabetes insipidus)
  • loss of vasopressin receptors (nephrogenic diabetes insipidus)
  • results in a constant H2O diuresis -> large volume of dilute urine due to lack of water resorption
  • not the same as an osmotic diuresis
  • H2O diuresis is not due to excessive solute loss
  • osmotic diuresis: H2O loss is due to excessive solute loss (water follows solute)
165
Q

diabetes mellitus

A
  • hyperglycemia (high glucose levels)
  • glucosuria
  • polyuria (osmotic diuresis)
  • polydipsia -> thirst
  • polyphagia -> hungry
166
Q

Renin-angiotensin-aldosterone system (RAAS)

A
  • loss of blood volume -> decrease blood pressure -> decrease GFR
  • decrease in NaCl transport across macula densa cells of distal tubule
    1. paracrine factors released -> signal granular cells (smooth muscle cells in wall of afferent arteriole) -> produce renin
    2. granular cells have beta 1 receptors that are also being signaled by increase in sympathetic activity due to decrease in BP -> produce renin
    3. bc granular cells are smooth muscles in the afferent arterioles they are directly reacting to decrease in BP -> produce renin
167
Q

renin is an enzyme

A
  • respond to reduction of flow and BP
  • decrease in blood volume -> decrease in GFR -> less flow past macula densa cell -> paracrine factors
  • granular cells secrete renin
  • renin- involved in salt and water balance
  • liver constantly produces angiotensinogen in plasma which is a substrate for renin -> cleaves -> produces angiotensin 1 in the plasma -> ACE cleaves angiotensin 1 into angiotensin 2
168
Q

angiotensin converting enzyme

A
  • ACE
  • cleave angiotensin 1 into angiotensin 2 in response to decrease in BP
  • inhibitors of ACE decrease BP
169
Q

angiotensin 2

A
  • increases blood pressure
  • hormone in plasma that affects other hormones
    1. acts on hypothalamus which increases thirst and vasopressin secretion -> increase volume and maintain osmolarity -> increase BP
    2. acts on adrenal cortex which increases aldosterone secretion -> increase Na reabsorption -> increase in volume and maintain osmolarity -> increase BP
    3. acts on proximal tubule -> increases Na reabsorption -> increases volume and maintain osmolarity -> increase BP
    4. acts on arterioles -> vasoconstriction (alpha 1 mostly skin and GI tract) -> increase BP
    5. act on cardiovascular control center in medulla oblongata -> increase sympathetic output -> increases cardiovascular response (beta 1 HR and contraction) -> increase BP
170
Q

aldosterone

A
  • steroid hormone
  • targets the collecting ducts
  • increases Na reabsorption
  • increases K secretion
  • made in adrenal gland (adrenal cortex)
171
Q

importance of K in plasma

A
  • most abundant intracellular ion (only 2% in ECF)
  • extremely important for maintenance of resting membrane potential in all excitable tissue
  • hyperkalemia- high K plasma, depolarizes cells, can lead to life-threatening cardiac arrhythmias
  • hypokalemia- low K plasma, hyperpolarizes cells, can lead to failure of respiratory and cardiac cells to contract
172
Q

renal regulation of K

A
  • collecting ducts

- regulated by aldosterone

173
Q

aldosterone triggers

A
  1. high K concentration (hyperkalemia) or very high osmolarity -> signals adrenal cortex -> produces aldosterone -> act on level of collecting duct -> increase Na reabsorption and K secretion into lumen
  2. low BP -> RAAS pathway -> signal adrenal cortex -> produces aldosterone -> act on level of collecting duct -> increase Na reabsorption and K secretion into lumen
174
Q

mechanism of aldosterone

A
  • steroid -> hydrophobic -> diffuses across lipid bilayers
  • binds to cytosolic receptor (inducible transcription factor) in the P cells of distal nephron -> causes translocation to the nucleus -> controls transcription
175
Q

overproduction of aldosterone

A
  • hypertension
  • due to excess Na reabsorption
  • hypokalemic -> excessive loss of K
176
Q

aldosterone is synthesized by cells of the adrenal cortex and stored in vesicles

A
  • aldosterone is a steroid
  • steroids are hydrophobic and are not packaged
  • it would diffuse out
  • steroids are also made on demand (not stored)
177
Q

atrial peptides

A
  • synthesized in the atrial cells of the heart
  • increased blood volume -> increased atrial stretch -> myocardial cells stretch and release ANPs -> natriuretic peptides -> natriuretic peptides target the kidney
  • absorbed into coronary vasculature
178
Q

natriuretic peptides

A
  • act on the kidney -> afferent arterioles dilate -> increase GFR and decrease renin -> increase in NaCl and H2O excretion -> blood volume decrease -> blood pressure decrease
  • Atrial natriuretic peptides are synthesized in advance and stored in cardiac muscle cells.
  • An increase in blood volume is an important stimulus for the release of atrial natriuretic peptides from cardiac muscle cells.
179
Q

The leakage of serum albumin into bowmans capsule would increase GFR

A

-true

-

180
Q

look this up in friday lecture :,( 10/30

A
  • pressure in the glomerular capsule is opposed by colloid osmotic pressure and hydrostatic pressure in bowmans capsule
  • when there is high hydrostatic pressure and colloid osmotic pressure the force pushing fluid into bowmans capsule will reduce
  • serum albumin accounts for most of colloid osmotic pressure -> water will follow
  • if hydrostatic pressure and colloid osmotic pressure increase so will
181
Q

vasodilation dilation will decrease GFR

A
  • true
  • if exit is “easy” pressure drops
  • low pressure leads to a decrease in GFR
182
Q

tubuloglomerular feedback relies upon hormones

A
  • false
  • paracrine factors are local and not in the blood -> not a hormone
  • paracrine factors travel in interstitial fluid
183
Q

vasopressin binds to vasopressin receptors on cells of collecting duct and initiates a signaling cascade that uses cAMP. the increase in cAMP causes the aquaporin to change from closed to open state.

A
  • false
  • vesicles undergo exocytosis in response to cAMP
  • nothing to do with open and closed state
  • aquaporins are like pores
184
Q

Elastic recoil of the lungs increases intra-alveolar pressure until it is greater than atmospheric pressure during expiration

A

true

185
Q

The P50 value of hemoglobin in pulmonary veins is less than the P50 value of hemoglobin in capillaries of an active skeletal muscle

A

true

-PO2 is lower in capillaries -> higher affinity

186
Q

The tracheal system of insects transports respiratory gases (O2 and CO2) and nutrients dissolved in hemolymph.

A

false

BIO 203 (5 decks)

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