comparative anatomy - respiratory system

RESPIRATORY SYSTEMRamyr Delos Reyes

Allyson Nicole ManaloClaudine P. Naz

Janyka Angela B. RomanKristel G. Zamora

Respiratory system -is a system consisting of specific organs and structures used for the process of respiration in an organism.

General FunctionRespiration-the act or process of inhaling or

exhalingRespiration includes:- Ventilation is the pumping of water in gills and

of air in lungs -External Respiration- exchange of gases with

the environment-Internal Respiration- essential gases are then

exchange with the tissues in the respective capillary beds

Respiratory Organs

GILLS Vertebrate gills are designed for

water breathing Mechanism of ventilation depends

on whether the gills are located internally or externally

1. INTERNAL GILLS2. EXTERNAL GILLS

LUNGS Designed for air breathing Elastic bags that lie within the body Volume expands when air is inhaled

and decreases when air is exhaled

GAS BLADDERS Are air filled with the air Swim bladders are used to control

the buoyancy of a fish

Gas bladders differ in lungs in two ways1. Gas bladders are usually situated dorsal

to the digestive tracts2. Gas bladders are not paired

Oxygen is released into the bladder Gas in the swim bladder is mainly oxygen

CUTANEOUS RESPIRATION Respiration through the skin Amphibians rely heavily in cutaneous

respiration

BREATHING EMBRYOS Chorioallantois in birds acts as respiratory

organs in birds It sustains the respiratory needs of the

chicken embryo for most of its time in the egg

VENTILATORY MECHANISM CILIA lines the routes along which water

current flows

MUSCULAR MECHANISM Ventilation on vertebrates usually

depends much on muscle action Ram ventilation is a technique by which

the fish’s own forward locomotion contributes to gill ventilation

1. Water Ventilation: Dual pump2. Air ventilation: Pulse pump3. Air ventilation: Aspiration pump

Air Ventilation: Pulse pump

FISHESRespiration: Gills or swim

bladder Gills External Gills-develop from surface

ectoderm and extend beyond the head Internal Gills- lie within the head Comprised of gill arches with gill

filamentslined with rows of lamellae (increase surface area)

Utilize countercurrent exchange(except for cartilaginous fishes)

blood flows oppposite to the direction of water movementg against gills

INTERNAL GILLS- develop from the pharynx as evaginations

called pharyngeal pouches Visceral grooves (opposite to the pouches) Closing plates (separates pouches and

grooves)

- The general structure of a mature gill is composed of several parts: Gill bars (support the gills) Gill rakers (prevents food particles from

entering) Gill rays Gill filaments and Gill lamellae

3 TYPES OF GILL BARS Holobranch Hemibranch Pseudobranch

AGNATHAN Pouched gills 6-15 pairs of gill pouches No gill Slits Hagfishes and lampreys

Cartilaginous fishes Septal Gills 5 “naked” gill slits Shark and rays

Bony Fihes Opercular gills (operculum) 5 gill slits Eels, salmon and milk fish

SWIM BLADDERS

Gas or swim bladders of fishes may be located high in the cavity to remain upright

1. Physostomous Function for respiration

2. Physoclitous Do not function for respiration

Serves as an hydrostatic organ Oxygen and carbon dioxide are

exchanged between the bladder and the blood

Also important in hearing and sound production

Amphibians

AMPHIBIANS They are cold blooded, meaning they

don’t need much oxygen 2 simple sacs

Lungs - don’t have diaphragms and they force

air into their lungs by moving their mouth (like swallowing) Buccal pumping

Four stages of lung ventilation1.) Buccal cavity expands to draw fresh air

in through the open nares2.) Glottis opens rapidly, releasing spent air

from the elastic lungs3.( Nares close, floor the buccal cavity rises

forcing the fresh air held in this cavity into the lung through the open glottis

4.) Glottis closes, retaining the air that has just filled the lungs and nares open again

Skin- Highly vascularized and moist- Very thin nd allows water to go through it- Aquatic Amphibians and anurans

Cutaneous respiration- The short trachea divides into 2 short

bronchi leading to the apex of each lung- The opening from the trachea to pharynx is

called the glottis supported by the larynx

Gills ( aquatic salamanders and tadpoles)- Made up of very thin blood vessels

surrounded by water channe;s- When amphibians undergo

metamorphosis into adult, gills are lost

Reptiles

REPTILES

-Lungs are large and varied

-Rely largely on LUNGS for gas exchange

-Have large lung volumes (10xmore volume

compared to mammals)

-Trachea and bronchi are larger than for amphibians and are supported by cartilaginous rings

-Supplemental cutaneous respiration is significant, but for the most part, paired lungs meet their respiratory needs

-Filling of the lungs in all the reptiles is based on an aspiration pump

- Exhalation of passive

CROCODALIANS- Use diaphragm muscle for lung

ventilation

-Contraction of the diaphragmatic muscles draws the liver back, increasing the volume of the lung cavity and dropping pressure within the lungs

- In caimans and other crocodiles, ribs rotate forward and outward, expanding the cavity around the lungs during inhalation

SQUAMATES (Snakes and Lizards )-Don’t have diaphragm muscles for lung

ventilation

-The muscle s used for locomotion are the same used for their respiratory systems

-Contracting and flexing body muscles move their ribs and lungs

In most snakes , there are usually two regions of the lung:

1. Anterior respiratory portion or faveoli2. Posterior saccular portion or avascular -Submergence in water- have large lungs

for large amount of oxygen for long dives (Hydrophinae and Arochordidae)

TESTUDINES (Turtles)-Having shells makes lung expansion more

difficult-Must use their limbs for lung ventilation

expels air from the lungs and pushing their limbs out of their shells expands the lungs

-Have complex lungs w/ large surface areas and volumes

Mammals

4.) Mammals- The chief organ in mammalian respiration is the lungs (located in the pleural cavities in the thorax)- More finely, homogenously divided and

more efficient- Aspiration pumps ventilates the lungs of

mammals- Breathing is dependent to the rib muscles

and diaphragm

SUCTION-PUMP MECAHNISM OF INHALATION AND EXHALATION

inhalationwhen the rib cage opens up and the diaphragm flattens and moves downward; air rush inside

lungs expandsdecrease in air pressure exhalation the diaphragm and rib

muscles relax to their neutral state that causes the lungs to contract; air flow out

squashing of lungs increase in air pressure

AIR FLOW IS BIODIRECTIONAL: Trachea primary bronchi

secondary bronchi tertiary bronchi alveoli

Trachea is a long structure of soft tissue; supported by rings of hyaline or fibrous cartilages; elastic connective tissue joins the ring and completes the tube where cartilage is absent Splits into two bronchi branches, each enters its

lung anterior and dorsal to the center Divides into numerous membranous bronchioles Alveolus- tiny air sacs; increase surface area;

where actual gas exchange occurs

The trachea, bronchi and bronchioles that transport gas to and from the alveoli is called the respiratory tree

No gas exchange occurs along the conducting passageway of the respiratory tree until air reaches the alveoli Epiglottis Glottis

Birds

5.) Birds- Have one way flow of air in their lungs-Lungs are small but compact, rigid and have a fixed volume-Have two lungs connected to trachea and ventilated by an aspiration pump-Birds have air sacs that collect air and then force the air through their lungs-Large air sacs joined the lungs and serve to ventilate them in crosscurrent circulation-Gas exchange in the blood actually occurs in the air capillaries-Bones contain air, not marrow

-Lungs receive fresh air during inhalation and exhalation-Air is pulled by a suction type pull and gas exchange are in the capillaries-Trachea is divided into two primary bronchi, termed mesobronchi, that do not enter the lung but extend posteriorly to reach the posterior air sacs-Gases diffuse between the lumen of the parabronchus and the connecting, blind-ended air capillaries

-Oxygen diffuses in turn from the air capillaries into the adjacent blood capillaries that give up carbon dioxide to the air capillaries-Walls of air and blood capillaries constitute the site of gas exchange-Air sacs function to lighten the birds like helium balloon, but air sacs provide no lift, and it is not the prerequisite for flight

When bird inhales, air is brought into the posterior air sacs, which expand. Upon exhalation, air is forced from the posterior sacs into the lungs; second inhalation will move the air from the lungs to the anterior air sac and second exhalation will push the air out

Advantages of one-way flow:1.)No residual volume; all old air leaves w/ each breath2.)Cross-current blood flow through the lungs

Pattern of Gas Transfer- Respiratory organ couples blood flow with ventilation

Rates of Gas transfer- Respiratory organs must also be designed to match the ventilation rate with perfusion rate- Breathing that is too fast or too slow is inefficient- Ratio of perfusion to ventilation depends on the species

Breathing in Water- Water is considerably denser than air

FISHES

Cartilaginous Fishes

Bony Fishes(Teleost)

Agnathans

Septal Gills Opercular Gills Pouched Gills

5 “naked” gill slits Usually have 5 gill slits

6 to 15 pairs of gill pouches

Sharks and Rays Eels, milkfish, salmon Hagfishes and Lampreys

Reptiles Amphibians Birds Mammals

No vocal cords Simple saclike lungs Most of the birds has nine sacs and these

are: anterior and posterior sacs

Human breathe through lungs

No True Diahragms Some amphibians have no lungs like

Salamander

The typical bird trachea is 2.7 times

longer and 1.29 wider than that of

similarly-sized animals.

Alveoli- spongy and has a little sac

Reptile lungs composed of three

and these are: Unicameral,

Multicameral and Paucicameral

Skin- Cutaneous Respiration

Avian lungs Trachea

Reptiles are capable of surviving for long

periods without breathing.

Many amphibians used gills at least

when they are young.

Bronchi- structure similar to trachea, flexible tubes with stiffening walls of hyaline cartilage

Bronchioles

BIRD FISH MAMMAL REPTILE AMPHIBIAN

•Unidirectional•Lungs•Aspiration pump•Longer and wider trachea compared to mammals•Air sacs

•Unidirectional•Gills•Dual pump•5 to 7 pairs of gills

•Bidirectional•Lungs•Aspiration pump•Muscles are used•Air are filtered

•Bidirectional•Lungs•Aspiration pump•Much larger lungs than mammals•Can survive for long periods without breathing•Muscles are used

•Bidirectional•Lungs and skin•Pulse pump•Simple saclike lungs