Tracheae - respiratory organs, Biology

Assignment Help:

Tracheae - Respiratory Organs

Tracheal respiration is characteristic of insects. Onychophorans, diplopods, arachnids, and chilopods as well use tracheal system for respiration. In this type of respiration air is carried directly to the tissues without the intervention of blood. Tracheal system commonly consists of a large number of interconnected small tubes, the tracheae. These open outside through minute pores called spiracles that are located on either side of the body. Air is pumped into and out of tracheae by these spiracles by the ventilating movements of the body-and gaseous exchange occurs directly in the individual cell. Single spiracle may serve for both inspiration and expiration; but generally there are numerous spiracles, some of them for inflow and others for outflow of the air. The pattern of the internal tracheal system is variable but there exists a pair of longitudinal trunks along with cross connections. The tracheae are supported through the thickened spiral rings of the cuticle, the taenidia. The rings resist compression (that is preventing collapse) but permit stretching of the tube. The tracheae divide and redivide to form-minute branches termed as tracheoles. These ramify by the different tissues of the body. In some insects the tracheal tubes are dilated to form air-sacs.

A number of tracheoles may be made by a single tracheole cell. In flight muscles of a number of insects, the tracheoles even push into the fibrils. The tracheole cuticle is not shed throughout molting as is the case of tracheae and after molting new tracheae are joined to old tracheoles. Exchange of gases by the tracheae is known to occur primarily by diffusion. However, spiracles remain closed most of the time and exchange possibly takes place as a result of both diffusion and ventilation. Studies have illustrated that the spiracles open very briefly and not all at once in response to a localized reduction in hemocoel pressure. The spiracle is literally sucked open and a "gulp" of air is taken in. The pressure drop results from inter-segmental muscle contraction and is under the control of nervous system that in turn may be regulated by the oxygen or carbon dioxide tension of the blood. More spiracles are hence open during flight compared with the insect at rest. Ventilating pressure gradients result from body movements, largely abdominal movements that bring about compression of the air sac and the longitudinal extension and contraction of trachea. Ventilation is facilitated by the sequence in which specific spiracles are opened and closed. Gases are exchanged by diffusion down a concentration gradient. Tracheoles are permeable to liquids, and in most insects their tips are filled with fluid. This fluid seems to be included in the final transport of oxygen. Some of the small insects like collembolans and proturans which live in moist surroundings lack tracheae and gas exchange takes place over the general body surface. Some immature aquatic insects also lack tracheae, specifically during early stages of development. Tracheae are as well usually present in adult insects which live in water. The adults merely use air from air bubbles or films held against the body surface by special "unwettable" (hydrofuge) hairs. But the nymphs and larvae of specific groups may possess special adaptations for gas exchange in water.


Related Discussions:- Tracheae - respiratory organs

Define types of root canal perforations according to size, Define Types of ...

Define Types of Root Canal Perforations According to size According to size: Small perforation: ( smaller than #20 endodontic instrument ) mechanical damage to tissue is

Explain the inoculating loops and needles, Explain the Inoculating Loops an...

Explain the Inoculating Loops and Needles? These are most commonly used tools for inoculation. The inoculating loop consists of insulating handle at the end of which inoculatin

Rk, how many chromosomes in human

how many chromosomes in human

What are some prophylactic measures for tapeworm infections, What are some ...

What are some prophylactic measures for tapeworm infections? The main prophylactic measures against taeniasis and cysticercosis are: not to ingest raw or badly cooked swine or

Light microscopy, LIGHT MICROSCOPY (LM) A study of the structure of organ...

LIGHT MICROSCOPY (LM) A study of the structure of organisms is an essential requirement of biology. However, unaided human eye cannot see objects smaller than 0.1 mrn(100 p) in d

Infectious and inflammatory conditions for lymphatic system, Q. Why in infe...

Q. Why in infectious and inflammatory conditions may clinical signs related to the lymphatic system occur? The lymph nodes or lymph glands have lymphoid tissue that produces ly

Quantitative real-time pcr, 1. You are given a pair of primers that has bee...

1. You are given a pair of primers that has been shown amplify a 125 bp DNA of interest specifically by a end point PCR- as there was only one PCR product with a size of 125 bp det

Feline panleukopenia, Feline panleukopenia It is arguably the most importa...

Feline panleukopenia It is arguably the most important of all feline viral diseases and all members of the family Felidae are susceptible. This disease is commonly found in kitten

Define drug effects on metabolism of dietary components, Define Drug effect...

Define Drug effects on Metabolism of dietary components? Drugs can also compete with, or inhibit, the metabolic conversion of some micronutrients to their active metabolites,

How to reduce calorie intake from fat, How to reduce calorie intake from fa...

How to reduce calorie intake from fat? Efforts should be made to increase the nutrition knowledge of the general public through mass media. The foods with lower fat co

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd