lec 5 respiratory system

define respiration and its purpose

Respiration is the sequence of events RESULTING in exchange of O2 and CO2 with external enviro and mitochondria

Purpose: GAS EXCHANGE (recieve O2 from enviro, remove CO2 from blood)

what is a diffusion constant k? what is flicks law? according to it, when will rate of diffusion be highest?

Flicks law:

Rate of diffusion = k x A x (P2-P1)/D

where k = Diffusion Constant (intrinsic propety of gas that relates to HOW WELL IT CAN MOVE THROUGH MEMBRANE)

where A = area for gas exchange

where P = partial pressure of gas on either side of barrier to diffusion (partial P = pressure exterted by induvidual gas)

where D = distance (thickness of barrier to diffusion)

Rate Diffusion INCREASE when:

-INCREASE memb surface AREA

-INCREASE DIFFERENCE in partial PRESSURE of gas on diff sides of memb

-INCREASE diffusion CONSTANT k

-DECREASE diffusion distance

diffusion constant looks at properties of solubility and molecular weight, which is based on what law? according to this now, when can cause increase rate of diffusion

Graham’s law:

Diffusion rate = solubility/square root of MW (molecular weight)

increase rate of diff: high solubility of gas, low molecular weight of gas (in liquid, solubility more significant factor, but opposite in air)

define ventilation and its 3 types and animals using each

Ventilation: active MOVEMENT of respiratory medium (AIR or WATER) across respiratory surface

1. Non-Directional - medium flow past surface in UNPREDICTABLE PATTERN (animals that use cutaneous respiration (exchange thru skin) or wave gills directly into enviro medium (earthworms, frogs, LUNGLESS salamanders)

2. Unidirectional - medium moves thru system in ONE DIRECTION (fish with internal gills (teleosts (most fish) and elasmobranch gills (sharks/rays/stakes), CROCODILES, and avian lungs (birds)

3. Tidal -medium moves in/out respiratory chamber in back-&-forth movement) (MAMMALS INSECTS REPTILES (non-avian, BUT NOT CROC, AIR-BREATHING amphibians/fish)

in non-directional ventilation, what does it mean id Po2 (partial pressure oxygen) in blood leaving gas exchanger can APPROACH Po2 in medium? what does graph for non-direct look like? what happens to O2 exchange efficiency and Po2 in blood if diffusion distance increases

-if blood Po2 approach Po2 in medium, medium is very WELL MIXED

-if D increase, O2 efficiency DECREASe and reduce blood Po2 leaving gas exchanger

in Tidal ventilation, what graph looks like? as animal breathes in, what happens to fresh and stale medium and is Po2 in cavity lower/higher than ext enviro? describe where O2 and PO2 go in tidal.

-as animal breathes in, incoming FRESH MEDIUM (air/water) MIXES with STALE MEDIUM left behind by previous breath in cavity (therfore Po2 in cavity LOWER than ext enviro)

-O2 diffuse into blood (flowing along surface like lung)

-PO2 of blood exiting surface will be in equilibrium w/ exhaled medium if D small

2 types of unidirectional ventilation and which animal

Countercurrent flow: OPPOSITE direction along surface (teleost and elasmobranch gills)

Crosscurrent flow: PERPINDICULAR direction (birds)

in countercurrent flow, is medium or blood higher PO2? what about crosscurrent?

in both: medium starts with high po2 and decrease steadily as it gives up O2, whiile blood start low po2 and steadily increase as pick up O2 (in counter, pick up while flow opp to medium, while in cross, pick up o2 at diff parts)

counter: medium always higher Po2 than blood (creaste small continuous diffusion gradient along surface (key to efficiency!!)

cross: blood po2 can rise HIGHER than final po2 of medium

whats boyles law

in closed space, pressure and volume are INVERSELY related (as vol increase, pressure decrease, vice verca)

what special pump do elasmobranchs shark/skate/ray use for gill ventilation? how does it work?

-Buccal pump

-mouth open = buccal cavity volume INCREASE = pressure decrease

-result: water is sucked into buccal cavity (through mouth and spiracles (like nostrils)

-then mouth/spiracles close and MUSCLES (around buccal cavity) CONTRACT = decrease volume = increase pressure to force water PAST GILLS and OUT THRU EXTERNAL GILL SLITS

-so buccal pump is dual-pumping mechanism where cavity alternates suction and force to move water unidirectionally over gills (even when animal stationary)

describe gills in teleost (bony) fish like location and how theyre well protected? what are the two lamellae in these fish gill arches?

-gills in opercular cavity (4 gill arches in each cavity)

-protected by flap-like operculum (better protection than exposed gills in elasmobranch)

-primary lamellae (2 rows of gill filaments in V-shape) and given structural support by gill arches

-secondary lamellae (rows of thin and highly vascularized (main surface) FOLDS that cover each primary lamellae) PERPINDICULAR TO PRIMARY LAMELLAE

based on ficks law, gas exchange is effective at fish gills and alveoli for 3 reasons:

1. lamellae have THIN membrane (less diffusion distance D)

2. lamellae provide LARGE SURFACE AREA for gills

3. LARGE PARTIAL PRESSURE gradient of gas between water and capillaries in lamellae

alveoli:

1. alveoli ONE CELL LAYER THICK (less diffusion distance D)

2. alveoli LARGE SURFACE AREA for lungs

3. LARGE PARTIAL PRESSURE GRADIENT of gas between inside of alveoli and capillaries

what type of tidal exchange fish gills use?

-COUNTERCURRENT exchange (blood thru capillaries in secondary lamellae in OPP direction to water passing thru gills)

explain the 4 steps of teleost fish using buccal-opercular pump for gill ventilation, and what 2 actions it requires to drive water in continuous unidirectional flow

-requires buccal (mouth) and opercular (gill cover)

1. start: MOUTH OPEN + opercular VALVE CLOSED = buccal and opercular CAVITY EXPAND (vol increase, pressure decrease (drawing water into mouth b/c negative pressure)

2. MOUTH CLOSED + opercular valve CLOSED = buccal cavity COMPRESSED + opercular vavity expanded still (negative pressure in opercular cavity move water from buccal cavity to gills)

3. mouth closed + opercualr valve OPEN = buccal/opercular cavity COMPRESSING (force water out)

4. mouth/valve open: buccal cavity expand + opercular cavity compressed

what is ram ventilations? what animals use this and why

ram ventilation: TELEOSTS (tuna salmon trout eel cof herring catfish) and ELASMOBRANCHS swim forward at HIGHER SPEED with MOUTH OPEN to allow water to flow across gills WITHOUT ACTIVE PUMPING OF MUSCLES surrounding buccal/opercular cavities

which sharks can breathe by alternating between buccal pumping at low speed and ram at high speed? which sharks are obligate ram ventilators and what this mean

-TIGER SHARK alternate

-great white, hammerhead, mako, whale shark DONT HAVE BUCCAL MUSCLES!!!! so they are obligate ram ventilators = NEED TO KEEP MOVING FORWARD b/c they only rely on ram ventilation (if stop, drown!!)

Ram ventilation advantages and disadvantages ( 2 each)

advantages:

1. allow fish to dedicate MORE ENERGY to swimming mUSCLES instead of buccal/opercular muscles so they ENHANCE SPEED

2. INCREASE WATER FLOW RATE over gills as fish swims faster

disadvantages:

1. OBLIGATE ram ventilators must swim CONTINUOUSLY to breathe for survival

2. opening mouth = increased drag = affect locomotion

explain how these air breathing fish get most/all O2 from air (like what special structure they have) : mudskippers, electric eels, catfish, bichirs, lungfish

-mudskipper: absorb O2 through skin (Cutaneous resp) and lining of mouth/throat AND special structure: MODIFIED GILL CHAMBERS help trap pockets of air/water on land (prevent gills from collapsing and allow gas exchange)

-electric eels: extensive folds in mouth (highly vascularized = substantial aerial gas exchange)

-catfish: highly vascularized stomach (lots of blood vessels) used for gas exchange after gulping air

-bichirs: paired lungs highly vascularized (can breathe surface air if water in habitat is poorly oxygenated)

-lungfish: HIGHLY VASCULARIZED LUNGS with folds/pocked to INCREASE SURFACE AREA

describe respiration in insects? what system they use and what special structures

-Tracheal system (network of tubules)

-large tracheae connect to spiracles (opening on suface along abdomen) where O2 ENTER and CO2 exit (rise in CO2 cause spiracles to open)(spiracles close to reduce water loss)

-Air sacs push air thru tubes when contracted

-Tracheal tubes & tracheoles are tubes that CARRY SIR THRU BODY TO CELLS/TISSUES

how are gases moved in insects? do they use blood flow?

NO BLOOD FLOW NEEDED (insects respiratory and circulatory systems are seperate, so air not circulated by blood)

-gases are moved mostly by MUSCLE CONTRACTIONS in ABDOMEN and arouns SPIRACLES

why can a frog survive out of water but not fish? (Compare their respiration) but why are fish gas exchange more effective (in water)

-fish have GILLS (cant support air, so membranes collapse, decreasing surface area, lack of O2 uptake)

-frog can respire through MOIST SKIN and LUNGS (but frog lungs not as efficient as fish gilld b/c smaller surface area AND new air mix with old air (tidal ventilation not as efficient as unidirectional)

why is fish gills more efficient than amphibian lungs

frog lungs not as efficient as fish gilld b/c smaller surface area AND new air mix with old air (tidal ventilation not as efficient as unidirectional)

why do reptiles need more O2 than amphiians? why cant they rely on skin for respiration like amphibians? how do their lungs compare?

REPTILES MORE ACTIVE!!!! need more O2

-dry scaly skin avoids water loss, so cant use for respiration

-reptile lungs have BIGGER SURFACE AREA

why do MAMMALS need more O2 than reptiles? how do lungs compare?

-mammals must maintain CONSTANT BODY TEMP by heating bodies metabolically, so need more O2

-INCREASED LUNG SURFACE AREA (aided with alveoli!!)

briefly draw out arrows for human/mammal resiratory firection from air inhaled to site of gas exchange

air inhaled thru nostrils → pharynx → larynx (voice box) → trachea (windpipe) → bronchi → bronchioles → alveolar ducts → alveolar sacs = site of gas exchange!!

why is trachea in mammals RIGID? what structures it has and its 2 main purposes? where else are these structures found

-Trachea rigid b/c walls have 16-20 C-shaped hyaline cartilaginous rings

-rings 2 purposes:

1. Keep trachea OPEN during BREATHING (prevent collapse)

2. Rings are incomplete (C-shaped) instead of complete (O-shaped) so that esophagus can EXPAND during PERISTALSIS

-these rings also found in PRIMARY BRONCHI!!!

where are alveolar ducts attached? each duct has how many alveolar sacs, and each sac has how many alveoli? what are alveoli wrapped by?

-alveolar ducts attached at ends of each bronchiole, each duct has 100 sacs, each sac has 20-30 alveoli (wrapped by capillaries)

describe respiration in birds? what structures it consist of, what type of ventilation, and describe the lungs?

-consists of LUNGS (rigid, little volume change) and NINE AIR SACS (expand/contract = air can move to lungs)

-UNIDIRECTIONAL air flow

describe where air go when bird breathe? and what does the last structure divide into and where gas exchange occur?

-birds breathe thru mouth/nostrils and air enters PHARYNX then to TRACHEA

-at syrinx (vocal organ), TRACHEA divide into 2 PRIMARY BRONCHI that split into SECONDARY BRONCHI: Dorsobronchi and Ventrobronchi that divide into PARABRONCHI (air capillaries intertwined with blood capillaries run between parabronchi THIS IS WHERE GAS EXCHANGE OCCURS!!!)

what animals have TWO cycles of breathing (inhale and exhale)? how do they do this and what happens during first inhale/exhale and second inhale/exhale?

Birds

-birds INHALE by EXPAND VOLUME of CHEST (due to contracting rib mucles and muscles attached to sternum) = cause increase volume in air sac and decrease pressure = AIR RUSHES IN along partial pressure gradient

FIRST INHALE:

-anterior/postieror AIR SACS EXPAND

-air travel thru TRACHEA (split into left/right primary bronchi)

-inhaled air travel down EACH PRIMARY BRONCHI and INTO POSTERIOR SACS

FIRST EXHALE:

-CHEST COMPRESS while anterior/posterior AIR SACS COMPRESS (pressure increase, volume decrease)

-air move along partial P gradient from posterior sacs INTO LUNGS (where gas exchange occurs)

SECOND INHALE:

-anterior/posterior AIR SACS EXPAND

-air travel from LUNGS INTO ANTERIOR SACS

SECOND EXHALE:

-anterior/posterior AIR SACS COMPRESS

-air move from anterior sacs BACK TO TRACHEA and expelled

do birds and mammals have a diaphragm?

mammals do only

what does unidirectional vs bidirectional air flow mean and which do avians vs mammals have

AVIAN: unidirectional: air moving thru lungs is MOSTLY FRESH (more O2)

MAMMAL: bidirectional: air flow moves back/forth into/out of lungs (new air mixes with old hair so less O2)

what are 3 ways the avian respiratory system more efficient than mammal

1. Unidirectional (higher O2 content)

2. Walls of lungs cant collaps (more rigid)

3. Air capillaires (in walls of parabronchial syst) have LARGER SURFACE AREA than alveoli in mammals