Respiratory System.pptx

8/22/2019 Respiratory System.pptx

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Surface area: Enhancements: gill lamellae, alveoli,succulations

Diffusion gradient: Increased by introducing external

(ventilation) and internal (heart) pumps along with the origin ofcounter current circulation

Most membranes are consisted of simple epithelium adjacentto endothelial lining of a capillary.

Materials must diffuse easily.

External respiration process of obtaining oxygenfrom the environment and eliminating carbon dioxide

Via respiratory membranes (except for earlyembryos)

It must be:

1. Highly vascularized

2. Epithelium is thin3. Moist surface

4. Must be in contact with environment (gills)/ environment

must be brought in contact with respiratory surface (lungs)


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External respiration Internal respiration

> exchange of carbon dioxidebetween capillary blood and tissue fluids.

Chief organs of external respiration in adult craniates

1. External, internal gills

2. Oropharyngeal mucosa

3. Air sacs/ lungs

4. SkinAdditional:

1. Bushy/filamentous outgrowths of pectoral fins maleLepidosirens

2. Posterior trunk region and thigh African hairy frog


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external internal


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Hagfishes Lampreys Afferent branchial ducts conduct

respiratory water from pharynx

pouches

Efferent ducts lead from pouchesexterior

water---nasopharyngeal duct---> velar

chamber pharynx and gill pouches Pharyngocutaneous duct (on the left)connects pharynx with last efferent

branchial duct/exterior; it is a modified last

gill pouch

No nasal norbuccal route for water

passage top the gills water enters and exits pharyngealpouches via external gill slits

Pharynx subdivided into:a. Esophagus

b. Ventral respiratory tube

gill pouches are lined with gill lamellaeand communicate directly with the

respiratory tube


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Most elasmobranch have 5 pairs of gill pouches (pentachid) and a pairof spiracles

No gill surface develops in the posterior wall of last pouch

External gill slits are naked no operculum Spiracle has one-way intake valve and is the exclusive incurrent aperturefor respiratory water (in Rajiformes)/ for much water (in sharks)

Gill slit gill chamber

Demibranch gill surface occurring in the posterior and anteriorwalls of first four chambers.

Last chamber lacks demibranch in posterior wall.

Pretrematic demibranch anterior wall Posttrematic demibranch posterior wall


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Interbranchial septum separates 2 demibranchs of asingle gill arch

Holobranch

2 demibranch of single gill arch +interbranchial septum + cartilages + blood vessels +

branchiometric muscles + nerves + connective tissues

Gill rakers protects gills from mechanical injury Demibranch surface consists of large numbers of transverse shelf

like folds to multiply surface area for gaseous exchange. Counter current flow of blood and water maximizes the

efficiency of gaseous exchange.

Water spiracle first two gill pouches Water mouth last three pouches.


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Pressure is nearly always higher in thepharyngeal chamber than in the gill pouches

to assure steady uninterrupted flow of waterover the gill lamellae

Chimaera resembles teleosts.


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Gill Apparatus

1.Pharyngeal

arches support

holobranchs

2.Water flow:

from

pharyngealcavity to the

exterior


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Gill Apparatus

1.Operculum

and opercularchamber

2.Shorter

interbranchial

septa

Difference with

Cartilaginous


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Operculum

Branchiostegal membrane supportedby branchiostegal rays

Branchiostegal membrane meet ventrally:

opercular chamber


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Water Flow

Mouth Open

Operculum Closed

Lowering pharyngeal floor

Mouth closed

Operculum open

Water out via opercular cleftElevating pharyngeal floor


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Most bony fishes:

4 holobranchs, 5 gillchambers, spiracle closed

Chondrosteans:

spiracle present


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Three Kinds:

1.External Gills: outgrowth from external surface of

one or more gill arches2.Filamentous Extensions of Internal Gills:

project through gill slits to the exterior

3.Internal Gills: hidden behind larval operculum


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Develop before gill slits open Can be retracted

Develop in: most dipnoans, all amphibians,

few ray-finned fishes


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Internal gillsand

operculumabsorbed

External gills

atrophy

FleshyOperculumencloses

external andinternal gills

Internal gills

developed

Pharyngealpouches in II

to V rupture

External gills

develop

In Anurans:


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Excrete nitrogenous wasteAllFishes

Excrete common marine salt via saltsecreting glands on lamellaeMarine

In salt water: excrete chloride

In freshwater: absorb chloride

Marine &

Lamprey

Release carbon dioxide into waterFishes that acquire

Oxygen from air in airsac


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Snatchbubblesabove water

Air in

contactwithorophrayngeal lining

Bubbleswallowed

Oxygen

extractedinstomach/intestine

Excesscarbon

dioxideeliminated

throughgills


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Cartilaginous & Ray

finned

Lobe-finned

Externalnares: Opento olfactory sac

Incurrent Aperture: water in

Excurrent Aperture: waer

out

Nostrils connected with

orophrayngeal cavity

Internal nares: openingto orophrayngeal cavity

Function: monitor chemicals in solution insurrounding water

Nares


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Whaleshave no nose, only blowholeson thetop of head

Nasal Canals: Choanae From paired nasal pits and oronasal groove In mammals:

Olfactory epithelium: restricted to upper chamber Nasal epithelium: ciliated glandular, in lower chamber

Parts: Hair: trap particles Venous plexuses: heat cold air Air sinuses: resonating chamber for vocalization


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Air (pneumatic) sac- Characteristic of osteichthyans

- From unpaired evagination from the foregut

- Filled with gases from atmosphere (N, O, CO2, Ar)- Some only develop sac temporarily as an embryo (few

marine teleosts and bottom dwellers)

- Called SWIM BLADDER in fishes (function: buoyancy)

- Called LUNGS in tetrapods (function: respiration)


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After budlike anlage for a swim bladder evaginates from foregut, resulting ductmay:

Retain connection with foregut- Called PHYSOSTOMOUS (duct remains open)

- Chondrosteans (duct leads from ventral aspect of esophagus), basal

neopterygians (from dorsal side), living dipnoans, some teleosts

Close during late development- Called PHYSOCLISTOUS (duct closes)

- Many teleosts

Swim bladder- Lie close to kidneys; retroperitoneal- Push their way caudad in roof of coelom between embryonic parietal

peritonium and body wall (may budge into roof of coelom if adult)

- May function as a hydrostatic organ, respiratory organ, may participate in

sound detection, or communication


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HYDROSTATIC ORGAN

- Teleosts- By regulating volume of gas in swim bladder, fishes are able to achieve a

body density, or specific gravity, equal to that of displaced water at selected

depth.

- Enables fishes to maintain an appropriate depth in a body of water or

hover to a specific location.

- Disturbances in water which leads to incomplete stability is solved by frequent

gentle lateral undulation of fins of fishes.

- Gas in hydrostatic swim bladder

- from blood from Red gland (localized rete of small arteries in bladder

lining) being transported actively into lumen of bladder

- Eventually resorbed into bloodstream in a pocket (modified epithelium)

- Pocket is closed during passage of gas into lumen of bladder and relaxed

during resorption of gas

- Gas bubbled to exterior through mouth for physostomes


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RESPIRATORY ORGAN- Physostomous fishes

- Air gulped at water surface => oropharyngeal cavity => swim bladder through

oropharyngeal pump => Air (now depleted) => expelled to oropharynx =>

mouth => back to water

- Air is expelled to the oropharynx through a vacuum created by lowering the

oropharyngeal floor while mouth and nares are closed.

- Protopterus and Lepidosiren (true lungfishes)

- Continuous gulping of air

- Gills incapable of providing sufficient oxygen- Can also absorb oxygen through skin (during tropical summer)


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ORGAN FOR PARTICIPATION IN SOUND DETECTION

- Cypriniformes

- Weber ossicles- connects anterior end of swim bladder with sinus impar which is

the extension of the perilymphatic space of inner ear

- Clupeiformes

- Anterior extension of swim bladder has direct contact with inner ear

- Neoceratodus (dipnoan), Polypterus & Calamoichthys , relict basal

neopterygians

- Lung functions only when oxygen content in water is low

- Polypterus, Amia, Dipnoans

- Supplied by arteries arising from 6th embryonic aortic arch (tetrapod

condition)

- Venous return directly to the left atrium of the heart for dipnoans (tetrapod

condition)


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ORGAN FOR COMMUNICATION- Thumping sounds- Contraction of striated muscles attaches to swim bladder

- Croaking/Grunting sounds

- Air forced back and forth between chambers separated by muscular

sphincters

BOTTOM FEEDERS- Swim bladder degenerates

- For optimization of body density

- Functions for hovering closer to food supply with minimal

expenditure of energy

- Analogous to salamanders who live in swift mountain streams


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Tetrapod lungs arise as lung bud.The opening in the pharyngeal floor is theglottis. The unpaired lung bud elongates

before bigurcating (dividing into two) toform bronchi and lungs. The part of the

lung bud between glottis and lungs

develops into larynx, tracea and bronchi.


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The larynx is a special part of the body

that functions as an airway to the lungs as

well as providing us with a way of

communicating (vocalizing). It is found

between the glottis and the upper end of

the trachea of tetrapods.


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Urodeles Nonmammaliantetrapods

-Primitive larynx,

single pair of lateral

cartilages surounding

the glottis

-incapable of

producing any sound

-2 pair of cartilages:

artytenoid & cricoid


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Reptiles Birdssilent animals but possess larynx, albeit

without a vocal cord, in the absence of

which they can at best produce ahissing sound.

- rudimentary larynx

-evolved a

secondary soundproducing organ

called syrinx


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Frog

-cricoid cartilage which is a modification of the first tracheal

ring and a pair of arytenoid cartilages, which support a pairof vocal cord that vibrates to produce sound.

-Males of frogs and toads in addition possess a pair of vocal

sacs which are evagination of oral cavity and serve as

resonance chambers to amplify sound.


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Mammals

- paired arytenoids + cricoid + thyroid + small cartilagescuneiforms, corniculates, procricoid including the epiglottis (closes

glottis

when swallowing)

-during ontogeny, paired cricoid and thyroids of embryos unite.

-sternothyroid and thyrohyoid provide larynx w/ moblity during

swallowing


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When not in use for vocalization, the cords

are relaxed and exhaled air passes b/w

them silently.


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When under tension, the cords vibrate, giving rise to

sounds. During vocalization, intrinsic muscles of the laynxalter the position of the thyroid and arytenoid cartilages

with respect to one another, thereby regulating the tension

on the cords.


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The pitch (frequency of vibration) of the human

voice is the function of the amount of tension w/inthe cords.

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Respiratory System.pptx