Download 10A Animal System Interactions

Rhonda Alexander IC Science Robert E. Lee
NS INSIDE AND OUT SKELETON
Skeletal syystems come
e in many form
ms. You have a skeleton innside of your body (endoskkeleton) made up of bones. Insects and ccrustaceans h
have skeletal ssystems on thhe outside orr their bodies (exoskeleton
ns) that are m
made of hard plates. h do not have bones or plates. They havve skeletons m
made up of fluids inside off Organisms like starfish
tubes within their bodies. The fluid skeletal syste
ems are calle d hydrostaticc. All animals that live outsside of the water need som
me kind of skeletal system tto support orr protect them
m. WHAT DO
OES THIS SYSTTEM DO? We alread
dy hinted at the purpose o
of a skeletal syystem. Protecction and sup
pport are the two big reaso
ons that organ
nisms have skkeletal system
ms. In your bo
ody, the skeleeton works veery closely witth the muscu
ular system to
o help you mo
ove. Without the bones of your skeleto n, you would be a blob of water‐filled tissues. Th
he bones creaate a framew
work to which your muscless and organs can connect. Your skeleto
on also playss a role in protection, espe
ecially in your head. The boones of your sskull protect your all‐impo
ortant brain. You
ur ribs protect most of you
ur internal orggans from im pact as well. Other animals with exoskeletons receive o
obvious prote
ection from th
heir skeleton. Crabs and in
nsects have haard shells made of chitin tto protect the
eir entire bodies. INTERACTING WITH OTHER SYSTEMS Your skeletal system does not work alone. We already mentioned the interaction with your muscular system. Muscles connect to your skeleton and they contract and move the skeleton along. Your skeletal system is made up of cartilage and calcified bone that work together. They help the process of movement happen in a smoother manner. The calcified bones of your skeleton also work with the circulatory system. Marrow inside of your bones helps produce the cells inside of you blood. Both red blood cells and white blood cells are created in your bones. MUSCULAR SYSTEM ‐ MEAT ON THE BONES Many advanced animals have muscular systems. You know you do. Did you know that your muscular system is made up of three different types of muscular tissue? You have smooth, cardiac, and voluntary muscle tissue in your body. Smooth muscle is muscle you rarely control such as the muscle in your intestinal tract. Cardiac muscle is very specific tissue found in your heart. Voluntary muscle is the muscle that helps you move. All of those tissues add up to a muscular system that is found through your body. There is more to the muscular system than the muscles that help you move. WHAT DOES THIS SYSTEM DO? The big purpose of the muscles found in your body is movement. We could be talking about the movement of your legs while you walk. We could be talking about the beating of your heart. We could also be talking about the contraction of a very small blood vessel in your brain. You have no control over most of the muscular system. You do control the voluntary muscle in your arms, legs, neck, and torso. You have little or no control over the heart or smooth muscle. Those other muscles are under the control of the autonomic nervous system. INTERACTING WITH OTHER SYSTEMS We just teased the fact that your muscular system is closely connected to the nervous system. That makes sense since you usually have to think before you can move. Even though thinking is not always involved, the neurons of the nervous system are connected to most of the cells in your muscular system. You have smooth muscles that line your digestive system and help move food through your intestines. Smooth muscle also surrounds your circulatory system and lymph system. Those muscle tissues are spread throughout your body and are even involved in controlling the temperature of your body. MUSCLES HELP YOU MOVE The main parts of your voluntary muscular system include the muscles, and tendons. The muscle is called the meatus. It happens to be the meat you eat from cows, sheep, and includes the muscle in your biceps. So your bicep it the meat, that meat needs to connect to the bones so that you can move. Tendons connect your muscles to your bone at insertion points. When the actin and myosin contract in the muscles, the muscle shortens and the bones are pulled closer together. Muscles called flexors force your joints to bend. Muscles called extensors cause your limbs to straighten. A bicep is a flexor and the triceps are extensors. You may have also heard of ligaments. They are batches of connective tissue that bind bones to each other. Muscles, tendons, and ligaments can been found working together in almost all of your joints. CIRCULATION IS THE KEY The circulatory is a system of vessels that pass through your entire body. You may read about two types of circulatory systems in animals. There are open circulatory systems in primitive organisms where you will find a heart that pumps fluids through the creature, but no complete system of vessels. More advanced organisms, including you, have closed circulatory systems where the heart is connected to a complete system of vessels. The fluids of a closed circulatory system never leave the vessels. WHAT DOES THIS SYSTEM DO? How does a circulatory system help you? It is the transportation system for your body. The circulatory system carries chemicals to all points in your body. The fluids also carry waste products and dissolved gases for your cells. Think of the chemical compounds as cars and the circulatory system as a network of freeways, main streets, and side streets. The cars can pass from one building to another using these streets in the same way that a compound might be created in the brain and sent to the kidneys. INTERACTING WITH OTHER SYSTEMS The circulatory system touches every organ and system in your body. The system is connected to all of your body's cells so that it can transport oxygen efficiently. When you breathe, the circulatory system carries oxygen to your cells and carries dissolved carbon dioxide back to the lungs. Every cell that needs oxygen needs access to the fluids in your circulatory system. The circulatory system and its fluids are super important to your digestive system that has absorbed nutrients from your food. Guess what? Hormones created by your endocrine system are sent through the body by the circulatory system. BASIC PARTS The core components of your circulatory system are the heart and vessels. You happen to have a four‐
chambered heart while other organisms may have one, two, or three chambers. The heart is the pump for the system. As blood is pumped from the heart, it passes through a system of arteries, arterioles, and then capillaries. The capillaries are the vessels that allow for most of the transfer of compounds and dissolved gases. Capillaries are very small and have thin walls to allow easier passage of compounds including nutrients, glucose, carbon dioxide, and waste products. After the capillaries, your blood passes through venules and veins. The veins lead the circulatory fluids back to the heart. That's it; the system is complete (and closed). RESPIRATORY SYSTEM ‐ ALL ABOUT BREATHING Your respiratory system is all about exchanging gases with the environment. Some animals such as amphibians are able to exchange gases through their moist skin. Fish have gills while mammals, birds, and reptiles have lungs. Your respiratory system is made of your nose and mouth, a tube called the pharynx, another tube called the trachea, and your lungs. You have two lungs and the exchange of gases between the circulatory and respiratory systems happens in the lungs. WHAT DOES THIS SYSTEM DO? Animals need oxygen (O) to survive. In fact, all organisms need oxygen to complete the process to burning glucose for fuel. Even protists and plants need oxygen, but as you become more active, you need a lot of oxygen. That's where your respiratory system comes in. It's purpose is to bring oxygen into your body. One of the products of cellular respiration is carbon dioxide. Your respiratory system also helps your body get rid of that carbon dioxide. While you have lungs, fish have gills that serve as the location for that transfer of gases. Whatever animal you study, oxygen is taken in and carbon dioxide let out. INTERACTING WITH OTHER SYSTEMS We already mentioned the circulatory system. With gases like oxygen and carbon dioxide (CO2), other compounds can be brought into the body by the respiratory system. Smoke can clog the alveoli in your lungs. You can inhale viruses and bacteria that could get you sick. You can also take in larger chemical compounds that can poison your body. All of these compounds can enter your blood stream via your respiratory system. Although it does not happen in all animals, your respiratory system also interacts with your digestive system. Your mouth and pharynx are both used to swallow and to breathe. There is a branching point where you will find the epiglottis that directs food to your stomach and air to your lungs. Your respiratory system even connects with the nervous system in your nose where you smell. Digestive System This is our favorite system. We love to eat and we love to poop. For the rest of the page we will refer to pooping as elimination. It's more technical that way. Anyway, your digestive system is all about getting food into your body, digesting the food, absorbing the nutrients you need, and elimination of the materials you don't need (feces). All animals have one sort of digestive system or another. Why? Anything that eats another creature (heterotrophs) must have a way of bringing nutrients in and getting rid of what they don't need. WHAT DOES THIS SYSTEM DO? What does the system do? We're going to use you as the basis for our explanation of the digestive system. Let's start with eating. You get hungry and you eat. Once you put the food in your mouth, you start to chew and begin a process of mechanical digestion that grinds food down into a pulp. Your body also starts to release enzymes that start the process of chemical digestion and the breakdown of biological molecules. Most chemical digestion happens in the stomach. The food moves through your digestive system and is eventually broken down into compounds and nutrients that your small intestine can absorb into the blood stream. The material you don't absorb continues into the large intestine where water is removed from the material and then whatever is left can be eliminated at your convenience. That's a decent overview of the process. INTERACTING WITH OTHER SYSTEMS The digestive system works very closely with the circulatory system to get the absorbed nutrients distributed through your body. The circulatory system also carries chemical signals from your endocrine system that control the speed of digestion. The digestive system also works in parallel with your excretory system (kidneys and urination). While the digestive system collects and removes undigested solids, the excretory system filters compounds from the blood stream and collects them in urine. They are closely connected in controlling the amount of water in your body. EXCRETION IS NOT ELIMINATION The excretory system is very important to your body and only has a few parts. In a similar way to removing solid waste from your body, you must also get rid of fluids. You know the results of the excretory system as urine. Urine is the result of the excretory system balancing the amount of water and salts in your body. We said the system is small. Your kidneys are the core organs involved in the excretory system. Related body parts include the ureters, bladder, and urethra. Once the urine passes through your urethra, that's it, it's out of your body. WHAT DOES THIS SYSTEM DO? What do those kidneys do? The regulation process of body fluids and salt levels is also called osmoregulation. The kidneys act as a filter. Eventually all of the blood in your body passes through the kidneys and they are able to do their filtering magic. The kidneys pull harmful molecules out of your bloodstream and leave the ones that are good for you. The kidneys are also key players in the hydration (water) levels for your body. Let's say you are in the desert and you haven't been drinking much water. Chemical signals are sent to your kidneys to reabsorb as much water as possible. The result is less urine creation and your body loses less water. A normal day has you creating about one and a half liters of fluid. INTERACTING WITH OTHER SYSTEMS The excretory system is a close partner with both the circulatory and endocrine system. The circulatory system connection is obvious. Blood that circulates through the body passes through one of the two kidneys. Urea, uric acid, and water are removed from the blood and most of the water is put back into the system. The endocrine system is the major controller of the excretory system. As levels of compounds and fluids are monitored, kidney function must be constantly altered to provide the best internal environment for your cells. If you drink too much water, hormones are released that allow for more urine production. If you are dehydrated, less urine will be produced. The kidneys are also tied to the endocrine system with the adrenal gland position on the top of each kidney. The adrenals release adrenaline into your body. NERVOUS SYSTEM ‐ I'M SENSING SOMETHING Since you're reading this page, we figure you've got a nervous system. If you were an insect you would also have a nervous system, but it would be a lot simpler. Even animals that don't think have simple nervous systems called nerve nets that help them move. Your nervous system is divided into two parts. Your central nervous system includes your brain and your spinal cord. Your peripheral nervous system is made up of the network of neurons that spans your organs, muscles, and body. The neurons in both systems work together to help you think, survive, and change the world around you. WHAT DOES THIS SYSTEM DO? The nervous system is about action and senses. Animals are able to sense what is going on in their surroundings and do something in reaction to that input. If you see a bike that might hit you, you jump out of the way. In that example, your nervous system was involved in many ways. Your eyes saw the bike, your brain figured out the bike might hit you, and your brain told your muscles to make your legs jump out of the way. You sensed and then acted. The nervous system also senses activity inside of your body. Most of the nervous system response inside of your body is not in your control. Your body automatically senses and reacts to stimulus. Think about eating your lunch. As you eat, your nervous system triggers the start of digestion and release of many hormones and enzymes throughout your body. INTERACTING WITH OTHER SYSTEMS Your nervous system interacts with every other system in your body. In the same way that all of your cells need oxygen transported by the circulatory system, all of your tissues and organs require instruction and direction from the nervous system. There is obvious interaction between your muscles and your nervous system. That interaction helps you move around and interact with your environment. There are many hidden interactions going on within your body. Your endocrine system works closely with your brain and central nervous system to control the creation of specific hormones and enzymes. Your digestive and excretory systems work with the nervous system in both conscious and unconscious ways. While digestion goes on without your thoughts, eating, peeing, and pooping are under your control. PARTS OF THE SYSTEM The nervous system is made up of nervous tissues that are, in turn, made up of many types of neurons. There are billions of neurons connected throughout your body. These neurons are connected end to end and transmit electrical impulses from one point to another. Your peripheral nervous system has two types of neurons that are constantly at work. Neurons that send impulses from the central nervous system to your limbs and organs are called efferent neurons. Neurons that receive sensory information and transmit to the central nervous system are called afferent neurons. Therefore, as the stimulus is received, the afferent neurons work and as reaction is needed, the efferent neurons go to work. ENDOCRINE SYSTEM ‐ ON A MOLECULAR LEVEL The endocrine system is one of the more difficult systems that you will learn about in class. Most of the activities of the system are not seen and you probably don't know that anything is happening. You definitely won't see any obvious problems, only the results of problems. Most of the early information about the endocrine system came from studying things that went wrong with the system. Even today, there are still many mysteries related to this system and it's activities. The best description we can offer is to describe the endocrine system as the chemical brother of the nervous system. While the nervous system transmits information and instructions using electricity, the endocrine system transmits information with chemicals and biological compounds. WHAT DOES THIS SYSTEM DO? This system controls many of the biochemical pathways that occur in your body. The core tool used by the endocrine system is a compound called a hormone. Your body uses dozens of hormones to regulate your growth, digestion, body temperature, and glucose metabolism (to name a few). A hormone released by an endocrine gland can travel throughout the body and change the activity of cells from many other systems. The endocrine system is also unique in that it uses glands and cells within organs that are all closely related to other systems. INTERACTING WITH OTHER SYSTEMS We don't know where to begin the discussion of endocrine interaction with other systems. The endocrine system is everywhere and the chemicals produced by the system act in a variety of ways on every cell of your body. The circulatory system is the transport system for endocrine information. While the nervous system uses neurons, the endocrine chemicals and hormones must circulate through the body via blood vessels. Many glands in your body secrete hormones into the blood. You have a pituitary gland in the base of your skull that releases hormones that control blood pressure and your excretory system. You have a thyroid gland in your neck that controls your bone growth rate and metabolism. You even have a tiny little adrenal gland above your kidneys that releases adrenalin if you get excited. Endocrine glands are everywhere. INTEGUMENTARY SYSTEM ‐ SKIN IS IN! Integumentary? That's a big word to describe something as simple as your skin. First, the skin is not all that simple. Second, integumentary systems take a wide variety of forms in animals across the world. Just think about the differences in the skin of a fish, a frog, a lizard, a bird, and a mammal. Scales, slime, feathers, and hair are all parts of the integumentary systems for animals. Your parts include the basic types of skin, hair, fingernails, oil, and sweat glands. They are found in integument layers called the epidermis (top), dermis, and subcutaneous (bottom). WHAT DOES THIS SYSTEM DO? The integumentary system is all about protection. The system protects your body from disease by providing a barrier to viruses and bacteria. The system protects your body from physical damage by offering a thick barrier that both contains your internal organs and stops large objects, like a rock from entering your body. The system also protects your body from dehydration, overheating, or freezing. The layer of skin can sweat and help your body cool or surround a layer of fat that keeps warmer temperatures inside. Did you know your skin makes up over fifteen percent of your body weight and is the largest organ in your body? Yes, your skin is considered an organ. INTERACTING WITH OTHER SYSTEMS How does the integumentary system work with other systems? We already spoke about your skin as one of the first defense mechanisms in your immune system. Your skin has tiny glands that secrete sweat and oil. Those glands are termed exocrine glands and are not like the glands of your endocrine system. While it may feel a bit slimy, those fluids decrease the pH on the surface of your skin and kill microorganisms. There are even enzymes in your sweat that can digest bacteria. The integumentary system also works closely with the circulatory system and the surface capillaries through your body. Capillaries near the surface of the skin open when your body needs to cool off and close when you need to conserve heat. We can't leave out the important sense of touch. Your nervous system depends on neurons embedded in your skin to sense the outside world. IMMUNE SYSTEM ‐ PROTECT THE HOMEFRONT Diseases are everywhere. You may have heard about tuberculosis, SARS, AIDS, malaria, or something as simple as the flu. All of those diseases can kill you. They would definitely kill you if you did not have an immune system. Your immune system is your microscopic armor that protects the cells of your body from bacteria, viruses, and poisons you might encounter every day. While other systems have major organs you can dissect and remove from the body, your immune system is relatively invisible and made of many different types of immune cells. WHAT DOES THIS SYSTEM DO? The immune system is there to keep you alive and healthy. The system can attack foreign invaders or it can go after cells created within your body that could endanger your life. Sometimes cancer cells are the targets of our immune system. As pathogens attack your body, the immune system begins a series of immunological defenses. You know when your immune system is at work because of the symptoms you might have. Fever, swelling, and a runny nose are all examples of symptoms during an immunological response. Your immune system can respond many ways to a problem. There would be one response to a knife wound, a separate response to hay fever and pollen, and a specific response to catching a cold. INTERACTING WITH OTHER SYSTEMS The immune system is like a small police force that constantly patrols every organ and tissue in your body. It works closely with the circulatory system for transportation needs and the lymphatic system for production of lymphocytes. It may surprise you, but one of the most important parts of the immune system is the entire integumentary system (your skin). Your skin is usually the first defense your body has against disease. It just makes sense. There is far more chance you will get dangerous bacteria or viruses on your skin and hands than breathe those microorganisms in your lungs. You have cells and compounds on your skin that help to kill any bacteria that appear. Always remember to wash your hands; most of the microorganisms that get you sick are picked up when you touch things. PROBLEMS WITH THE SYSTEM We wanted to talk a little about diseases and failures of the immune system. AIDS is one of the most well‐known diseases that can hurt the immune system. AIDS is a disease where specific immune cells such as helper‐T and inducer‐T cells are killed. Without those cells, the immune system cannot work properly and even minor diseases can kill the organism. There are also genetic problems with immune systems. Something as simple as an allergic reaction happens because an individual cannot properly tolerate certain allergens. Inflammation and hay fever occur. Normal individuals can destroy those allergens, but people who are "allergic" cannot defend themselves. You could have allergies to animals, food, or plants. Some allergic reactions are so extreme they can kill. LYMPH SYSTEM ‐ CLEANING UP THE FLUIDS We have already discussed the circulatory system that has your blood and transports nutrients, dissolved gases, and waste products through your body. There is a closely related system called the lymphatic system. While the circulatory system circulates blood throughout your body, the lymph system moves lymph fluid through the body. Not all organisms have lymph systems. This system is one of the more advanced systems you will find in animals. WHAT DOES THIS SYSTEM DO? The lymph system is designed for transportation in a way similar to the circulatory system, but it I not about oxygen and nutrients. The lymph fluid acts like the clean‐up crew for your body. You know that you are made of water and fluids. There are very few solid parts of your body. All of those fluids are usually contained in cells. There are some fluids found between the cells or actually seep out of the cells. This intercellular fluid slowly begins to accumulate and must be returned to the cells and the blood stream. Enter the lymph system. The lymph system gathers those fluids and returns them to your blood. The lymph system is also closely associated with your immune system and swelling of tissues after an injury. INTERACTING WITH OTHER SYSTEMS We keep talking about the collection of fluids. The lymph system is not a closed system in the way your circulatory system is closed. The lymph system collects and transports. Collection of fluids begins at the capillaries of the circulatory system and then the fluid directed through a series of vessels that become the thoracic duct. That duct is connected to the largest vein in your body, the superior vena cava, and returns the fluid to your heart and circulatory system. The lymph fluid moves through the vessels as you move the voluntary muscles in your body. Ever go on a plane and have your feet swell up? Because you are sitting in one place and not moving around, fluid collects in your feet and they swell. The more you move, the more effective your lymphatic system becomes.