Circulation and Excretion Notes PDF

1.4 Circulation: Types of Circulating Fluid: There are two main ways to categorize circulating fluids: On the basis of location:  Intracellular fluid (ICF): This fluid is found inside cells and makes up about 67% of total body water. It contains essential elements for cell function like...

1.4 Circulation: Types of Circulating Fluid: There are two main ways to categorize circulating fluids: On the basis of location:  Intracellular fluid (ICF): This fluid is found inside cells and makes up about 67% of total body water. It contains essential elements for cell function like electrolytes, proteins, and nutrients.  Extracellular fluid (ECF): This fluid is found outside cells and makes up about 26% of total body water. It includes:  Blood: This red-coloured fluid transports oxygen, nutrients, hormones, and waste products throughout the body. It consists of plasma (liquid portion) and cellular components like red blood cells, white blood cells, and platelets.  Lymph: This clear, colourless fluid bathes tissues and collects excess fluid, waste products, and immune cells. It eventually drains into the bloodstream. On the basis of function: Transport fluids: These fluids move essential materials around the body. Examples include blood (oxygen, nutrients, hormones), lymph (waste, immune cells), and cerebrospinal fluid (protects and nourishes the brain and spinal cord). Secretory fluids: These fluids are produced by organs and glands and have specific functions outside the bloodstream. Examples include: Digestive fluids: Saliva, gastric juice, bile, and pancreatic juice aid in digestion and absorption of nutrients. Exocrine fluids: Sweat helps regulate body temperature, while mucus moistens and protects surfaces. Reproductive fluids: Semen for fertilization and vaginal fluid for lubrication. It's important to note that some fluids can fall into both categories. For example, blood is a transport fluid in the vascular system, but it also has secretory functions within tissues. So, depending on which classification system you use, there are a variety of circulating fluids in the body, each with unique functions vital for maintaining health and well-being. Coelomic Fluid: Coelomic fluid is a fluid found within the coelom, which is a body cavity in many animals. It plays several important roles, including: Hydrostatic skeleton: In some animals, coelomic fluid provides support and structure, acting like a hydraulic skeleton. This is particularly important in invertebrates that lack bones or other rigid structures. Transport: Coelomic fluid can transport nutrients, gases, and waste products throughout the body. This is especially important in animals with simple circulatory systems. Lubrication: Coelomic fluid can help to lubricate internal organs, reducing friction and allowing them to move smoothly. Immune function: Coelomic fluid can contain immune cells and other molecules that help to defend the body against infection. Reproduction: In some animals, coelomic fluid is involved in reproduction, such as by transporting sperm or eggs. The composition and function of coelomic fluid can vary depending on the type of animal. In some animals, it is a simple fluid, while in others it is more complex and contains a variety of cells and molecules. Here are some additional details about coelomic fluid in different groups of animals: Invertebrates: Coelomic fluid is found in many invertebrates, including annelids (e.g., earthworms), mollusks (e.g., snails), and echinoderms (e.g., starfish). In these animals, it often plays a major role in their internal functions. Vertebrates: Coelomic fluid is also found in some vertebrates, such as fish and amphibians. However, in these animals, it is less important than in invertebrates, as they have more developed circulatory and immune systems. Lymph: The tissue fluid Lymph is a crucial component of your body's defense system, playing a key role in maintaining fluid balance and fighting infection. Composition of lymph: Similar to blood plasma, lymph is a clear, watery fluid but without red blood cells and containing fewer proteins. It carries essential elements like:  White blood cells (lymphocytes), crucial for immune response.  Fats absorbed from the digestive system.  Waste products and cell debris. Role in the lymphatic system: Fluid balance: Lymph collects excess fluid from tissues, preventing swelling and ensuring proper hydration. Immune defense: White blood cells in lymph patrol for pathogens and fight infections. Lymph nodes act as filters, trapping and destroying harmful substances. Fat absorption: Dietary fats from the small intestine are transported via lymph as chylomicrons. Key features lymphatic system: Network of vessels: Lymph travels through a network of thin-walled vessels called lymphatic capillaries, which merge into larger lymphatic vessels. Lymph nodes: These bean-shaped structures are scattered throughout the body, filtering lymph and housing immune cells. One-way flow: Unlike blood, lymph has no central pumping organ and relies on muscle contractions and breathing to flow in one direction towards the bloodstream. Potential issues: Lymphedema: Blockage in lymph vessels can lead to lymphedema, causing swelling and discomfort. Lymphoma: Cancer of the lymphatic system can affect lymph nodes and other components. Maintaining healthy lymph: Exercise regularly: Movement helps pump lymph through the vessels. Maintain a healthy weight: Excess weight can impair lymph flow. Eat a balanced diet: Nutrients and vitamins support immune function and overall health. Manage stress: Chronic stress can weaken the immune system. Blood: Blood, the very essence of life, carries much more than just a dramatic red color. It's a complex and fascinating fluid vital for our existence, constantly circulating and performing numerous critical functions. Here's a deeper dive into its composition and roles: Composition of blood: Blood is a mixture of various components:  Plasma: This straw-colored liquid makes up about 55% of blood volume and contains:  Water: essential for hydration and transporting substances.  Proteins: like albumins for transporting nutrients and antibodies for fighting infection.  Electrolytes: minerals like sodium and potassium for balancing body fluids and nerve impulses.  Hormones: chemical messengers regulating various body functions.  Glucose: fuel for cells.  Blood cells: Suspended in plasma, these cellular components comprise about 45% of blood:  Red blood cells (RBCs): carry oxygen from the lungs to tissues and are packed with hemoglobin, the iron-rich protein responsible for the red color.  White blood cells (WBCs): part of the immune system, fighting infections and foreign invaders. Different types of WBCs have specialized roles.  Platelets: tiny cell fragments helping in blood clotting to prevent excessive bleeding. Functions of blood:  Blood plays a multitude of crucial roles:  Gas transport: RBCs deliver oxygen from the lungs to tissues and remove carbon dioxide, a waste product, for exhalation.  Nutrient transport: Plasma carries nutrients absorbed from the digestive system to cells.  Waste removal: Blood carries waste products like carbon dioxide and urea to the kidneys and liver for elimination.  Temperature regulation: Blood flow helps regulate body temperature by distributing heat.  Fluid balance: Blood volume and composition influence fluid balance throughout the body.  Hormone transport: Hormones travel through blood to reach target organs and exert their effects.  Clotting: Platelets and clotting factors in plasma work together to seal wounds and prevent blood loss.  Immune defense: WBCs identify and combat pathogens, preventing infections. Blood Disorders: Various conditions can affect blood and its functions:  Anemia: reduced red blood cell count or hemoglobin, leading to fatigue and weakness.  Leukemia: cancer of the white blood cells.  Hemophilia: a bleeding disorder due to impaired blood clotting.  Thrombosis: blood clot formation within a blood vessel, potentially leading to strokes or heart attacks. Blood Donation and Transfusion: The remarkable ability of healthy individuals to donate blood helps save lives through transfusions for various purposes: Replacing blood loss after accidents or surgeries. Treating blood disorders like anemia. Supporting organ transplantation procedures. Blood donation is a safe and essential process that helps many in need. Types of Circulation: i. Protoplasmic Streaming: Protoplasmic streaming, also known as cytoplasmic streaming or cyclosis, refers to the circulation of the cytoplasm within plant and animal cells. This fascinating phenomenon involves the movement of cellular components, including organelles, nutrients, and waste products, throughout the cell. Mechanism: The driving force behind protoplasmic streaming is a complex interplay between two cellular structures: Microtubules: Hollow, tube-shaped structures that act as tracks for movement. Motor proteins: Specialized proteins like myosin that "walk" along microtubules, carrying organelles and other materials along with them. The energy for this movement comes from ATP (adenosine triphosphate), the cell's main energy currency. Functions of Protoplasmic streaming: While the exact reasons for protoplasmic streaming are still debated, it's believed to play several important roles: Efficient transport: In large cells, diffusion alone wouldn't be enough to effectively distribute materials. Streaming speeds up the movement of essential molecules and organelles, ensuring their availability throughout the cell. Mixing and mixing: It helps mix cellular contents, promoting even distribution of nutrients and facilitating reactions. Positioning of organelles: Streaming can help position organelles in specific locations within the cell, where they can function more efficiently. Waste removal: It may aid in the removal of waste products from the cell interior. Types of protoplasmic streaming: Depending on the movement pattern, protoplasmic streaming can be categorized as: Rotational: The cytoplasm flows in a circular pattern around the cell. Oscillatory: The cytoplasm moves back and forth in a wave-like pattern. Shuttle streaming: Organelles move in opposite directions along specific tracks. Examples: In plant cells, protoplasmic streaming is evident in the movement of chloroplasts, allowing them to capture sunlight more efficiently. In amoeba, a single-celled organism, streaming helps them change shape and move. In nerve cells, streaming may play a role in transporting neurotransmitters along long axons. Protoplasmic streaming is a essential cellular process that contributes to the efficient functioning of plant and animal cells. While its exact functions are still being unravelled, it's clear that this internal river plays a vital role in maintaining cellular health and life itself. ii. Open and Closed Circulation: Open vs Closed Circulation: Different Routes for Different Creatures There are two main types of circulatory systems in the animal kingdom: open and closed. Each has its own unique features and limitations, catering to the needs of specific organisms. Open Circulation:  Found in: Primarily invertebrates like insects, mollusks, and some crustaceans.  No vessels: Blood, often called hemolymph, flows freely through open spaces called sinuses within the body cavity (hemocoel).  Heart: A simple, pulsating heart pushes hemolymph into the hemocoel, but doesn't create continuous flow.  Pressure: Low blood pressure due to the open system limits circulation distances and efficiency.  Gas exchange: Specialized organs like gills or tracheae are responsible for gas exchange directly with the surrounding environment.  Waste removal: Waste products diffuse out of hemolymph into surrounding tissues and are then eliminated through specialized organs.  Advantages: Simpler system, suitable for smaller and less active organisms.  Disadvantages: Limited efficiency, restricts body size and activity level. Closed Circulation:  Found in: Vertebrates like humans, fish, and birds, and some invertebrates like earthworms.  Vessels: Blood flows through a network of closed tubes called arteries, veins, and capillaries.  Heart: A complex, muscular heart pumps blood continuously throughout the vessels, creating high pressure.  Pressure: High blood pressure enables efficient circulation over long distances, supporting larger and more active bodies.  Gas exchange: Specialized organs like lungs or gills exchange gases with the external environment, and the blood transports them throughout the body.  Waste removal: Dedicated organs like kidneys filter waste products from the blood, which are then eliminated through specialized systems.  Advantages: Highly efficient, allowing for larger body size and complex activity.  Disadvantages: More complex system, requires more energy to maintain. Both open and closed circulation systems have evolved to meet the specific needs of different organisms. Open circulation offers a simpler solution for smaller, less active creatures, while closed circulation provides the efficiency needed for larger, more active bodies. Understanding these differences helps us appreciate the diverse adaptations found in the animal kingdom. Single and Double Circulation: Single and double circulation are two different types of closed circulatory systems, meaning the blood travels through a network of enclosed vessels (arteries, veins, and capillaries). However, they differ in the pathway the blood takes within this closed system: Single Circulation:  Found in: Primarily fish, some amphibians, and some invertebrates like cephalopods (octopus, squid).  Pathway: Blood flows through the heart only once per complete circuit.  Heart: Has two chambers - one atrium and one ventricle.  Process: Deoxygenated blood enters the atrium from the body tissues. The ventricle pumps the deoxygenated blood to the gills (or other gas exchange organs) for oxygenation. Oxygenated blood flows back to the heart, entering the same atrium as the deoxygenated blood. The ventricle pumps the oxygenated blood out to the body tissues.  Advantages: Simple and efficient for organisms with lower metabolic needs.  Disadvantages: Limits the amount of oxygen delivered to tissues, restricting potential body size and activity level. Double Circulation:  Found in: Mammals, birds, reptiles, and some amphibians.  Pathway: Blood flows through the heart twice per complete circuit.  Heart: Has four chambers - two atria and two ventricles.  Process: Deoxygenated blood enters the right atrium from the body tissues. The right ventricle pumps the deoxygenated blood to the lungs for oxygenation. Oxygenated blood flows back to the heart, entering the left atrium. The left ventricle pumps the oxygenated blood out to the body tissues.  Advantages: More efficient, delivering more oxygen to tissues, allowing for larger bodies and higher activity levels.  Disadvantages: More complex structure and requires more energy to maintain. Both single and double circulation are effective systems for transporting blood throughout the body, but they are suited for different needs. Single circulation is simpler and works well for animals with lower oxygen demands, while double circulation is more complex and allows for increased activity and growth potential. Hearts Types : Hearts come in a variety of shapes and sizes depending on the animal they belong to. Here are some of the main types of hearts: 1. Two-chambered hearts: Found in fish, some amphibians, and some invertebrates like cephalopods (octopus, squid). Has one atrium and one ventricle. Blood flows through the heart only once per complete circuit. 2. Three-chambered hearts: Found in amphibians like frogs and toads, and some reptiles like snakes and lizards. Has two atria and one ventricle. Blood partially mixes in the ventricle before being pumped out to the body. 3. Four chambered hearts: Found in mammals, birds, and some reptiles like crocodiles and alligators. Has two atria and two ventricles. Blood flows through the heart twice per complete circuit, once through the lungs for oxygenation and once through the body. This is the most efficient type of heart and allows for high levels of activity. Additional heart types: Accessory hearts: Some animals, like octopuses, have accessory hearts that help to pump blood to specific organs. Invertebrate hearts: Invertebrates have a wide variety of heart types, some of which are very different from vertebrate hearts. Interesting facts about hearts: The human heart beats about 100,000 times per day. The heart is the strongest muscle in the body. The heart can regenerate to a small extent. Some animals, like whales, have hearts that can weigh over 1,000 pounds. Excretion and Osmoregulation: Concepts of osmoregulation and excretion: Osmoregulation and excretion are two intertwined processes that are essential for life. Let's delve into each concept and see how they work together to keep our bodies in balance. Osmoregulation is the process by which organisms maintain the osmotic pressure of their body fluids. Osmotic pressure is the pressure exerted by solutions due to the presence of dissolved solutes. It's like the crowd pushing against the entrance of a popular club; the more people (solutes) crammed in, the higher the pressure. Our bodies consist of about 60% water, distributed between cells (intracellular fluid) and outside of cells (extracellular fluid). Maintaining the right balance of water and solutes in these compartments is crucial for various cellular functions, like enzyme activity and nutrient transport. How organisms osmoregulate?: Concentration: They can adjust the concentration of solutes in their body fluids to match the surrounding environment. For example, saltwater fish have more solutes in their body fluids than freshwater fish to prevent water loss. Permeability: They can control the permeability of their cell membranes, allowing water and solutes to move in and out as needed. Excretion: They can eliminate excess water and solutes through excretion. Excretion is the process of removing waste products and excess water from the body. This helps maintain the proper composition of body fluids and prevents the buildup of toxic substances. Excretory Organs in Animals Excretory organs are responsible for removing waste products from the body. These waste products are typically the result of cellular metabolism or ingested substances that the body cannot utilize. Different animal groups have evolved distinct excretory organs to suit their specific needs and environments. Some common excretory organs found in animals: Invertebrates  Flame cells (found in flatworms): These specialized cells have cilia that beat to draw in fluid and filter out waste.  Nephridia (found in annelids, like earthworms): These tubular structures filter waste from the blood and release it through excretory pores.  Malpighian tubules (found in insects): These thin tubes absorb waste products from the hemolymph (insect blood) and release them into the digestive tract.   Green glands (found in crustaceans): These specialized organs filter waste from the blood and release it through ducts. Vertebrates  Kidneys (found in most vertebrates): These bean-shaped organs filter waste products from the blood and produce urine.  Lungs (primarily for gas exchange): While not exclusively excretory, the lungs also play a role in removing carbon dioxide, a waste product of cellular respiration.  Skin (through sweat glands): Sweat glands help eliminate excess water, salts, and urea from the body. The type of excretory organ an animal has often depends on its environment and the nature of its waste products. For example, aquatic animals may have simpler excretory systems that can easily release waste into the surrounding water, while terrestrial animals may need more complex systems to conserve water. Plants: Plants use stomata in their leaves and stems to release water vapor through transpiration. They also store waste products in vacuoles or excrete them through their roots. The interplay between osmoregulation and excretion: Osmoreceptors in the body detect changes in solute concentration. When body fluids become too concentrated (hypertonic), the body excretes excess solutes and retains water. When body fluids become too dilute (hypotonic), the body excretes water and retains solutes. By working together, osmoregulation and excretion ensure that our body fluids remain within a narrow range, optimal for cellular function and overall health. Categorization of animals on the basis of principle nitrogenous excretory products Animals can be categorized based on their primary nitrogenous excretory product, which reflects their evolutionary adaptations and resource management strategies. Here are the three main categories: 1. Ammonotelic:  Excrete ammonia, a highly toxic but readily soluble waste product.  Examples: Aquatic animals like fish, crustaceans, and some amphibians.  Advantage: Easy expulsion through gills or permeable skin in aquatic environments.  Disadvantage: Requires large amounts of water for dilution and elimination, making survival in terrestrial environments challenging. 2. Ureotelic:  Excrete urea, a less toxic compound requiring less water for excretion.  Examples: Mammals, amphibians (adult stage), and some aquatic invertebrates.  Advantage: Lower water loss compared to ammonotelic animals, enabling adaptation to terrestrial environments.   Disadvantage: Requires energy to convert ammonia to urea via the urea cycle. 3. Uricotelic:  Excrete uric acid, a very insoluble and energy-efficient waste product.  Examples: Birds, insects, reptiles, and some land snails.  Advantage: Minimal water loss, ideal for arid environments or water conservation.  Disadvantage: Requires more energy to produce than urea and can form painful stones if not excreted properly. It's important to note that some animals might exhibit variations or adaptations within these categories. Additionally, other minor nitrogenous waste products exist, but their categorization is mainly based on the dominant one. The choice of excretory product is influenced by factors like water availability, energy expenditure, and evolutionary history. Some animals can switch between different excretory modes depending on their environment or developmental stage (e.g., tadpoles are ammonotelic while adult frogs are ureotelic). This categorization provides a broad overview, and further classification within groups based on specific excretory organs and mechanisms exists.