Gas Exchange in Fish

Gas Exchange in Fish

Recap Possible words Tracheae Diffuses Pizza All parts Branch Slower


Quicker Hydrogen Oxygen Carbon dioxide Atmosphere Diffusion Answers

The breathing system in insects consists of a series of tubes called tracheae. The tracheae connect to the atmosphere by openings called spiracles. Air diffuses through the spiracles and tracheae to all parts of the body supplying the organs directly with air.

The tracheae branch repeatedly until they end as very fine, thin-walled tubules through which oxygen and carbon dioxide can diffuse freely into and out of the tissues. Along a diffusion gradient When cells are respiring oxygen is used up and so its concentration towards the end of the tracheoles falls. This creates a diffusion gradient for O2 towards the cells. CO2 is produced by cells creating a diffusion gradient with the atmosphere (CO2 moves out of the insect). As diffusion in air is much quicker than in water, respiratory gases are

exchanged quickly by this method Oxygen vs. Water Life on land poses a continual conflict between the needs for oxygen and water. Terrestrial insects have to cope with obtaining oxygen from air without dying

from dehydration. It is vital for terrestrial insects, especially those such as locusts that live in desert conditions, to be able to exchange respiratory gases without losing too much water. Gas Exchange in Fish

Lesson Objectives (ALL) Practice and develop our dissection skills and anatomical drawing skills. (D) How are fish gills adapted to maximize gaseous exchange? (C) What is the difference between parallel flow and counter current

flow? (A/B) How does counter current flow increase the rate of gas exchange? Waterproof body Large or small SA:V? What does that mean for gas exchange?

Fish are aquatic animals adapted to extracting oxygen from water. Oxygen content in air; 20.9 % Oxygen content in water; approx 0.8 % Therefore fish have to pass large volumes of water over their gas exchange systems relative to the volumes of air ventilated by terrestrial

animals. Some fish actively pumping water!! Fish can extract as much as 80% of available oxygen passing through its gills Due to;

1. A very large surface area for gaseous exchange 2. A short diffusion distance across the gaseous exchange system 3. A high concentration gradient between the blood in the gills and the water passing over them 1. Large surface area Developed a specialised internal

gas exchange surface: the gills Structure of the gill 2. Short diffusion distance Gill plates exceedingly delicate and very thin so that blood flowing through them is only a short distance from seawater (about 5m in active fish such as mackerel).

3. High concentration gradient Countercurrent exchange in bony fish The blood and the water flow over the gill lamella in opposite directions 1.Blood that is already well loaded with oxygen meets water, which has its maximum concentration of oxygen. Therefore diffusion of oxygen from the water to the blood takes place.

2.Blood with little or no oxygen in it meets water which has had the most, but not all, of its oxygen removed. Again, diffusion of oxygen from the water to blood takes place. Countercurrent exchange Relatively constant rate of diffusion Parallel flow system dogfish

Blood and water move in the same direction and only about 50% of the oxygen is absorbed. Haemoglobin Fish blood contains haemoglobin. Helps to carry oxygen away from the gills and maintain a high concentration gradient.

Unloading is made easier by the Bohr effect! Examiners Tips Maintaining steep diffusion gradients for oxygen involves bringing it constantly to the exchange surface (by ventilation) and carrying it away from the surface (by mass transport in

the blood) Always refer to blood and water flowing in opposite directions in the counter current system. Describe how this maintains a difference in oxygen concentration and a diffusion gradient across the whole length of the gill lamella. Dissection Questions

Sketch the fish head and label the relevant parts.

Remove the fish gills and identify the; Gills Operculum Single gill lamella Blood vessels Examine a single gill.

Can you detect the gill plates? (running a needle along the surface of the lamellae may help) Examine the gill under a microscope

Add labels to explain how water passes through the gills Approximately how many lamella are there per gill? How many plates per lamellae? Make a detailed and labelled drawing

Take a horizontal cross section of the gill parallel to the lamellae and examine it under the microscope Now take a vertical cross section of the gill (at right angle to the lamellae) Make a detailed and labelled drawings identifying the lamellae and gill plates Examine the blood vessels, how many cells separate the lumen of the vessels and the exterior?

Gas exchange in Leafs Lesson Objectives (D) How do plants exchange gases? (C) What is the structure of a dicotyledonous plant leaf? (A/B) How is the leaf adapted for efficient gas exchange?

Plant cells All respire like animal cells Use oxygen and produce carbon dioxide Some carry out photosynthesis Use carbon dioxide and produce oxygen Thus, plant cells able to interchange gases

between respiration and photosynthesis Structure of a plant leaf short, fast diffusion pathway Very large surface area compared with the volume of living tissue Thus, no specialised transport system is needed for gases No living cell is far from the external air, and

therefore a source of oxygen and carbon dioxide Diffusion takes place in the gas phase (air), which makes it more rapid than if it were in water Adaptations for rapid diffusion; Large surface area (thin flat shape of leaves) Many small pores, called stomata (mostly in lower epidermis) Numerous interconnecting air-spaces that

occur throughout the mesophyll. Examiners tip The diffusion gradients in and out of the leaf are maintained by mitochondria carrying out respiration and chloroplasts carrying out photosynthesis. Summary Questions

Summary Questions 1. State two similarities between gas exchange in a plant leaf and gas exchange in a terrestrial insect. 2. State two differences between gas exchange in a plant leaf and gas exchange in a terrestrial insect. 3. What is the advantage to a plant of being able

to control the opening and closing of stomata? Answers 1. Any 2 from; no living cells is far from the external air / diffusion takes place in the gas phase / need to avoid excessive water loss / diffuse air through pores in their outer covering (can control the opening and closing of these pores). 2. Any 2 from; insects may create mass air flow plants never do / insects

have a smaller surface area to volume ratio than plants / insects have special structures (tracheae) along which gas can diffuse - plants do not / insects do not interchange gases between respiration and photosynthesis plants do. Homework Questions WARNING Some independent research required! 1. Diffusion is a passive, physical process that takes place everywhere. Why is diffusion not the only means of gaseous exchange in large organisms? (2 marks)

2. With reference to surface area and heat exchange explain why having small ears is an adaptaticounter-current exchange with reference to gaseous exchange in fish. 3. By what process does carbon dioxide enter photosynthesizing cells in leaves? 4. Why is there a conflict between obtaining carbon dioxide for photosynthesis and conserving water? 5. Why does the stoma open when guard cells are turgid? 6. How do the stomata in plant cells open and close? 7. What are xerophytes? 8. on to a cold environment. (2 marks)

9. In which structures in the tracheal system does most gaseous exchange take place? Explain why. (2 marks) 10. Name two features of gills that maximize diffusion of respiratory gases across their membranes. 11. Explain the term halophytes? 12. How are xerophytes adapted to minimise water loss? 13. What is the significance of sarguaro cacti being shaped like an organ pipe?

Recently Viewed Presentations

  • Grammar of English

    Grammar of English

    Grammar of English: Introduction Eng 314 * * * * * * * * Goals Be able to determine the category of each word in a text. Be able to find the major phrases in a sentence and their functions...
  • DNA, RNA, and protein synthesis

    DNA, RNA, and protein synthesis

    A gene is a specific sequence of DNA that codes for a specific protein. Replication - when the strands of DNA unwind and an exact copy of the entire length of DNA forms during cell division. This is important so...
  • The Argumentative Essay:

    The Argumentative Essay:

    MLA Citation The GOOD NEWS about website sources is that you can use EASYBIB.COM to HELP you build a citation. BUT We can not assume that Easybib will create a complete citation AND Easybib includes things that are NO LONGER...
  • Administrative Leadership Meeting Tuesday, September 13, 2016 Chancellor

    Administrative Leadership Meeting Tuesday, September 13, 2016 Chancellor

    Internal Sponsors,NC Local Government,Nonprofit Organizations,State and Local Governments Outside NC. ... FY2016 Technology Commercialization & New Ventures in Review. 291 new invention disclosures filed. 56 new patents awarded. 164 commercialization agreements signed.
  • The Bible, Science and Creation - Apologetics Forum

    The Bible, Science and Creation - Apologetics Forum

    Atheists can't live a consistent life. Must live as if human life is sacred. Must live as if life has meaning. Rational statements require rational context. Atheist's beliefs are not rational. Theism explains human experience. The universe and life require...
  • ANL Talk

    ANL Talk

    Mass threshold Total Angular Momentum Orbital Angular Momentum Spin Angular Momentum Means: Quark Spin=1 (3 = 2 x 1 + 1) Quark Orbital Ang. Mom. = 0 Total J/y Spin = 1 Means: Total J/y Spin = 1 Parity is...
  • IEEE and IEEE Computational Intelligence Society Vincenzo ...

    IEEE and IEEE Computational Intelligence Society Vincenzo ...

    Rami Abielmona, David Fogel, Vincenzo Piuri, Enrique Ruspini, Gary Yen Overview Mandate for OpsMan: Constitution, BL Roadmap for the OpsMan Summary OpsMan in CIS Constitution CONSTITUTION, ARTICLE II - BYLAWS AND OPERATIONS MANUAL Section 2. A Society Operations Manual shall...
  • Strategic Management- Chapter Four

    Strategic Management- Chapter Four

    Use the five forces of competition model to explain how above-average returns can be earned through each business-level strategy. Describe the risks of using each of the business-level strategies. MORNING JOE IN THE AFTERNOON IN CHINA, INDIA, & BEYOND: THE...