Week 6-7 Respiratory System (CO2 Application) PDF

AQUA 3115: PHYSIOLOGY OF AQUATIC ORGANISMS WEEK 7 RESPIRATORY SYSTEMS OBJECTIVE Differentiate and characterize the organs involved in the proper functioning of respiratory system WHAT DO I KNOW ABOUT FISH RESPIRATION?  TRUE OR FALSE? 1. The gills are the main organ by which gas...

AQUA 3115: PHYSIOLOGY OF AQUATIC ORGANISMS WEEK 7 RESPIRATORY SYSTEMS OBJECTIVE Differentiate and characterize the organs involved in the proper functioning of respiratory system WHAT DO I KNOW ABOUT FISH RESPIRATION?  TRUE OR FALSE? 1. The gills are the main organ by which gases are exchanged between the fish and the surrounding water. TRUE  TRUE OR FALSE? 2. Through the gills, fish are able to absorb oxygen and give off carbon dioxide. TRUE  TRUE OR FALSE? 3. Respiration is the intake of O2 for metabolism/energy production and release of CO2 into the environment as an end product of metabolism TRUE  TRUE OR FALSE? 4. Respiratory system has functions other than for respiration such as osmoregulation and detoxification. TRUE  TRUE OR FALSE? 5. The paired nostrils or nares in fish are used to respire in water. FALSE  BASIC KNOWLEDGE Respiration is the intake of oxygen for metabolism (energy production) & release of carbon-dioxide into the environment as an end product of metabolism.  BASIC KNOWLEDGE The primary purpose of the fish’s respiratory system is to regulate gas exchange.  BASIC KNOWLEDGE The transfer of oxygen (O2), carbon dioxide (CO2) and to a lesser extent, ammonia (NH3) between the environment & the cell or tissue site of production  BASIC KNOWLEDGE Organisms that live in water need to obtain oxygen from the water in dissolved form. BASIC KNOWLEDGE Oxygen dissolves in water but at a lower concentration than in the atmosphere. The atmosphere has roughly 21 % oxygen which in water is way lower (20x lesser). The gills are the main organ by which gases are exchanged between the fish and the surrounding water Through the gills, fish are able to absorb oxygen (in dissolved form) and give off carbon dioxide  BASIC KNOWLEDGE Aquatic organisms (particularly the fishes) have evolved gills to take up the dissolved oxygen from water. Fish nostrils serve no role in respiration. They are completely sensory. Gills are composed of several structures: Gill arches - bony or cartilaginous arches that support the gills. Gill filaments – highly vasculated organs that conduct gas exchange. Gill rakers - raker-based filtering apparatus for suspension feeding & have no purpose for gas exchange Operculum – is protective covering for the gills. iStock credit: mariaflaya  general steps in the fish respiratory system 1. Water is taken in through the mouth continuously. 2. Water passes backward through the gill arches and over the gill filaments. 3. The capillaries on the gill filaments extract dissolved oxygen from the water. 4. Dissolved oxygen moves directly into the bloodstream. 5. The heart pumps oxygenated blood throughout the body. 6. Deoxygenated blood, high in carbon dioxide, is circulated back to the gill filaments. 7. The capillaries on the gill filaments release excess carbon dioxide into the water. 8. Water exits through the gill slits continuously, at the same time water enters. Describing the respiratory pump in fish Fish need a more efficient method of acquiring oxygen than terrestrial animals Unidirectional system, water always moves one way across gills and out operculum ✓ No mixing of fresh and respired water maintaining highest possible partial pressure of oxygen (pO2) at gill surface Review… Respiration is the process that involves production of energy through the intake of oxygen & the release of carbon dioxide as by-product of oxidation Review… Respiration in fish takes place with the help of gills basically comprising of gill filaments, gill arches, lamellae & capillaries. Review… Fishes and other organisms are able to survive the aquatic environment due to their ability to obtain dissolved oxygen through a vascularized gills, lungs, or skin to transport and unload this oxygen to the tissues. note… In some scaleless fish, gas exchanges takes place through the skin Fishes that can obtain oxygen from the air has evolved with modified gills, mouth cavity, intestines and gas bladder Let us dissect the gills… In general, there are four pairs of gills in bony fishes while six or seven pairs in cartilaginous fishes Let us dissect the gills… 3 Basic components of the gills 1. Gill Arch 2. Gill Filament 3. Gill Lamellae Let us dissect the gills… Let us dissect the gills… Gill Arches (Branchial Arch)- bony or cartilaginous structures that support the gill filaments. Note: Every gill arch has a gill raker Let us dissect the gills… Gill Rakers- bony or cartilaginous structures that are found on the gill arches of fish; small, finger-like projections that protrude from the gill arches Let us dissect the gills… Gill rakers do have role to play in the gas exchange; instead, they filter food particles & other debris out of the water as it flows over the gills (sieve food particles). Let us dissect the gills… The number and length of gill raker vary from species to species due to their specific feeding strategies. Let us dissect the gills… filter feeder Let us dissect the gills… generalist omnivore Let us dissect the gills… carnivorous Let us dissect the gills… detritivorous-invertivorous Let us dissect the gills… Gill Filaments (aka primary gill lamellae) - thin, hair-like structures that protrude from the gill arches; responsible for exchanging oxygen and carbon dioxide with the water Let us dissect the gills… Gill Lamellae (aka secondary gill lamellae) - thin, flattened structures that are found on the gills; each gill lamella is lined with tiny blood capillaries, assisting in the intake of oxygen in the blood Let us dissect the gills… Other important parts of the gills… Gill slits - small openings found on the sides of the head of some aquatic animals, including sharks, skates, and rays. Other important parts of the gills… Gill slits allow water to be drawn into the mouth and over the gills, which are located within the body cavity. Other important parts of the gills… Other important parts of the gills… Other important parts of the gills… Operculum|Gill cover - bony structure that covers & protects the gills; composed of two plates, known as the opercula, that are located on either side of the head, behind the eyes miscellaneous.. Types of Gill Internal gill – positioned inside the body; covered by operculum or gill slit External gill – branched type of gills that are positioned outside the body Gill type… External gills, though rare in fishes, are commonly observed on the aquatic larva of most species of lungfish, bichirs, and salamanders. Gill type… External gills are retained in the neotenic adult salamanders and some species of adult lungfish. platinum bichir Lung fish Axolot salamander Physiology of gills Fish use two main methods of gill ventilation to extract oxygen from the water: 1. Buccal pumping 2. Ram ventilation Physiology of gills Buccal pumping - a method of gill ventilation that is used by many species of fish; involves the fish opening and closing its mouth to draw water over the gills Gas exchange in gills Physiology of gills Ram ventilation - method of gill ventilation that is used by some species of fish, such as salmon and trout which are active swimmers that need a constant supply of oxygen to support their high metabolism Ram ventilation