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Human Physiology: The Systems of the Body By Mindy Chen Enter The Human Body: Systems Menu Nervous System Immune System Reproductive System Circulatory System Digestive System Skeletal System EXIT Endocrine System Muscular System Excretory System Integumentary System Respiratory System The Nervous System: Standards Standards: b. Students know how the nervous system mediates communication between different parts of the body and the body’s interactions with the environment c. Students know how feedback loops in the nervous and endocrine systems regulate conditions in the body d. Students know the functions of the nervous system and the role of neurons in transmitting electrochemical impulses e. Students know the roles of sensory neurons, interneurons, and motor neurons in sensation, thought, and response MENU The Nervous System: Introduction This system is made up of: nervous tissue Brain Spinal cord Peripheral nerves All other body systems may be present, but humans would essentially be nothing except for a body if not for the nervous system, which, by responding to stimulus from both the outside and inside of the body allows for proper, healthy function. The nervous system processes this information to help a person survive, either voluntarily (as in dayto-day actions) or involuntarily (as in constant breathing, digestion, or heart function). It is also essential for memory. The Nervous System: Neurons Neurons are… Basic units of the nervous system Control functions and movements of the body Carry impulses (electrical signals of the nervous system) The 3 kinds of neurons a neuron Sensory neurons Responsible for bringing impulses detected by sense organs to the brain and spinal cord Interneurons Act as a “middle-man” by relaying impulses between sensory and motor neurons Motor neurons Responsible for bringing impulses from the brain and spinal cord to the various muscles and glands of the body The Nervous System: Nerve Impulse Once an (electrical) nerve impulse is initiated, it travels all the way in whatever direction it is moving How it basically works Sodium ions (a positive charge) change the charges of neuron’s cell’s membranes The impulse is conveyed along, the opposite charge on the outside of the membrane is turned negative Nerve impulses travel along neurons which are connected in long pathways called nerves. If there is damage, as shown in the neuron on the right side, then an impulse cannot be delivered. The Nervous System: Sectors of the System This graphic demonstrates the parts of the brain and the branches of the nervous system. Central Nervous System Made up of: brain, spinal cord This is the main central system of the nervous system and functions to deal with and work with information Peripheral Nervous System Made up of: all nerves and related cells (not including brain and spinal cord) Sensory division Conveys impulses to the central nervous system from the body’s sense organs Motor division Conveys impulses to the muscles or glands that are sent from the central nervous system Autonomic Nervous system Deals with the involuntary functions and workings of the human body The Circulatory System: Standards MENU Standards: – a. Students know how the complementary activity of major body systems provides cells with oxygen and nutrients and removes toxic waste products such as carbon dioxide The Circulatory System: Introduction This system is made up of: – Heart – Blood Vessels – Blood Without the circulatory system constantly working, one would soon die. That is because all the cells in a human body need the oxygen and nutrients that the circulatory system brings to them. Also, the cells produce wastes including carbon dioxide that can only be effectively removed through the circulatory system. Blood is pumped through the blood vessels by the heart to every reach of the body’s cells. The Circulatory System: The Heart The Heart – A hollow organ – About the size of a person’s fist – Contracts (or beats) to pump blood to all of the various parts of the body via blood vessels. – Completely surrounded by pericardium which is a sac of tissue that protects the heart Diagram labeling the various areas of the heart and the direction of blood flow. How the Heart Beats (turn up the volume!) – Also known as the pacemaker, the small group of cardiac muscle cells (in the right atrium) called the sinoatrial node set the entire heart’s beating rhythm – The heart pumps blood faster or more slowly depending on the body’s needs for oxygen/nutrients An animation showing the direction of blood flows through the heart The Circulatory System: Blood Vessels Arteries- thick walled, large, hollow blood vessels that carry oxygen-rich blood (except for pulmonary arteries which carry oxygen-depleted blood from the heart to the lungs) Capillaries- tiny blood vessels in which the key workings of the circulatory system is carried out; this is where cells exchange their waste products (including carbon dioxide) for nutrients, and most importantly, oxygen Veins- valves in these blood vessels help to prevent gravity from getting in the way of conveying nutrient depleted blood back to the heart The Circulatory System: Paths of Circulation CLICK HERE to view animation on circulatory pathways as shown in image below Pulmonary circulation (contact w/ respiration) – Direction blood is pumped: from right side of the heart to lungs – At lungs, carbon dioxide is removed from the blood and the oxygen is replenished Systemic circulation – Oxygenated blood (that is back from the lungs) returns to the left side of the heart and is pumped and released to the rest of the body – The bod’s cells take in the oxygenated and nutrient filled blood while putting out their carbon dioxide into the bloodstream – This causes the blood to become oxygen depleted eventually – The oxygen depleted blood makes its rounds back to the right side of the heart for pulmonary circulation to begin again. The Skeletal System: Components This system is made up of: Bones Other connective tissue such as: cartilage – strong and flexible connective tissue ligament – very tough and strong band of connective tissue that attaches to bones to keep them together Femur, or thigh bone, as seen in an ultrasound image MENU Click on the walking skeleton above to view another animation that also realistically simulates human movement The Skeletal System: Function Functions Supports the body by providing a sturdy framework Provides protection for vital internal organs with, for example, the rib bones Allows for movement when muscles attached to them as a result of joints Stores minerals Produces red blood cells in the marrow of the bones Diagram of a human skeleton with the names of the bones labeled The Skeletal System: Bone Structure Diagram of a bone. Bones have a hard, yet semi-flexible surface and are a frame for the human body. Inside the bone is a hollow region which contains bone marrow, where red and most white blood cells and platelets are created. The Skeletal System: Joints Joints – site where bones attach to each other Types Immovable Joints – (a.k.a. fixed joints) – these don’t allow motion Example: joints of the skull Slightly Moveable Joints – allows for some, but limited motion Example: joints of the spine between the vertebrae Freely Moveable Joints – allows for motion in one or even more ways Example: knee joint, shoulder/hip joint This is a labeled diagram of a knee joint (one example of a freely movable joint The Muscular System: Standards Standards: – h. Students know the cellular and molecular basis of muscle contraction, including the roles of actin, myosin, Ca+2, and ATP MENU The Muscular System: Introduction This system consists of: – Muscle tissue (of the three different kinds) all throughout the body which total up to more than 40% of the mass of an average human Without the muscular system, humans could not move. The runner in the slide background could not run and much less hold a starting position. Though the skeleton gives a framework to human bodies, muscles are required to provide the movement factor. The Muscular System: Muscle Tissue 1 – Skeletal Muscles This image shows the front an back view of a person in terms of skeletal muscles Skeletal muscles, as seen under microscope These are usually found attached to bones and carry out the voluntary motions of a human Consists of long, striped, striated (meaning the alternating dark and light bands one would see going across the cell), multinucleated cells – these properties, especially the fact that the cells are narrow and lengthy have caused them to also be called muscle fibers The Muscular System: Muscle Tissue 2 – Smooth Muscles These usually carry out actions that are involuntary (uncontrollable by the human’s will) Examples of where these are located: hollow structures such as stomach, intestines (both small and large) and blood vessels The cells that form smooth muscles have: single nucleus, no striations, and can function without nerve stimulation These parts of the digestive system shown are all examples of locations where smooth muscles do their work Smooth muscle, as seen under microscope The Muscular System: Muscle Tissue 3 – Cardiac Muscles Animation of a pumping heartpowered by cardiac muscles The only place you can find these are in the heart Cardiac muscle cells: have striations, but only one nucleus and only occasionally two nuclei Obviously the cells must be run in an involuntary manner so as to keep the heart pumping and the person alive Cardiac muscles, as seen under a microscope The Muscular System: How Muscles Contract Muscle Contraction – How does a muscle fiber contract? Simply put, the thin filaments called actin slide across and over the thicker filaments called myosin ATP that can be made by either cellular respiration or fermentation on the part of cells, serves as the fuel for powering muscle fiber contraction – From where does this contraction arise? (What triggers it?) Calcium ions (Ca+2) are stimulated to be released in a muscle fiber by the impulse resulting from a certain neurotransmitter’s (called acetylcholine) presence These calcium ions affect certain regulatory proteins that are responsible for letting actin-myosin interaction happen – When does the muscle relax? When acetylcholine is no longer present, or an enzyme blocks the passage of acetylcholine to the cell The location of actin and myosin is demonstrated above Animation above shows how the actin (the thinner lilac colored filaments) and myosin (thicker pink colored filaments) interact to contract and relax at the minute level. The Integumentary System: Components • This system is made up of: – – – – Skin Hair Nails Various glands The surface of the skin is covered with pores. MENU This is a crosssection of skin as viewed under a microscope. Notice the hair and the hair follicle. The Integumentary System: The Skin Skin (largest component of integumentary system) Layer of skin as viewed under a microscope. Evident are the layers of skin: upper, lower, and the layer of fat beneath them. – Many Protective Functions • Helps prevent infections, injuries • Maintains body temperature- layer of fat beneath the skin layers helps to insulate the body • Removes wastes from the body passed out through the pores • Protection against ultraviolet sun radiation- significant amount of radiation deflected – Contains sensory receptors that can detect sensations from the outside world (including heat, cold, pain, pressure, etc.) The Integumentary System: Layers of the Skin 1 Epidermis – the outermost, exposed layer of skin – 2 layers of epidermis – Inner layer- made up of living cells that divide quickly and push the older cells upwards • The older cells’ organelles disintegrate; they begin to produce keratin, a tough fiber-like protein – Outer layer- made up of the older cells after they die (dead cells) • Very flexible yet tough and waterresistant • A new outer layer is exposed in the time of once every four or five weeks – Does not contain blood vessels, so small scratch or cut on the skin’s surface causes no bleeding – Contains melanocytes, cells that produce dark brown pigment called melanin responsible for coloring people’s skin The epidermis is the uppermost layer of the skin and is exposed to the outside world. The Integumentary System: Layers of the Skin - 2 Dermis- inner layer of skin underneath the epidermis – This layer contains… - Collagen fibers - Sense organs - Blood vessels - Smooth muscles - Nerve endings - Hair follicles - Glands – Different types glands in the dermis – Sweat glands: perspiration to cools body (sweat evaporation removes heat) – Sebaceous (oil) glands: makes The dermis contains many oily substance (sebum) that glands, blood vessels, and spreads out on the skin’s other structures. surface to help maintain the epidermis’ (outer skin layer’s) - Function of Blood Vessels - widen pliable and water-resistant to allow more conveyance of heat qualities from within the body in warm or hot conditions and narrow to prevent excessive heat loss on cold days The Integumentary System: Hair and Nails • Hair and Nails (both formed by keratin) – Hair • Protects body in variety of ways including from sun’s UV (Ultraviolet) rays, heat, cold, and dirt/dust – Nails • Protect the ends of people’s fingers and toes On the left are pictures of nails which demonstrate their distinct and necessary location. To the right is a diagram of a hair in its hair follicle The Respiratory System: Standards MENU Standards: a. Students know how the complementary activity of major body systems provides cells with oxygen and nutrients and removes toxic waste products such as carbon dioxide The Respiratory System: Introduction This system is made up of: Nose Pharynx Larynx Trachea Bronchi Lungs What is the main purpose of human’s having a respiratory system? Basically, the respiratory system allows humans to exchange carbon dioxide, the waste product of many body functions, for oxygen, which powers many human processes. The Respiratory System: The Process of Breathing/Respiration - 1 CLICK HERE and scroll down to view an animation of how the diaphragm works The Upper Respiratory System How a person breathes to take in air and exhales to get rid of “used” air The chest cavity containing the lungs is completely sealed up, so when the diaphragm, a long, flat muscle beneath the cavity contracts (downward), like a vacuum, a person immediately sucks in air into their lungs To exhale, the diaphragm relaxes (upward) and thereby forces air out of the lungs Let’s follow the journey of breathed air: Upper Respiratory System 1. enter through the nose 2. passes through the pharynx (tube for both food and air) 3. goes through pharynx where the vocal cords are located and into the trachea toward the lungs All along the way, measures are taken to ensure the cleanest air reaches the lungs Air must be slightly heated, made moister, and screened Dust particles filtered out by small hairs Mucus produced to trap particles and make the air moist The Respiratory System: The Process of Breathing/Respirations - 2 Let’s continue following the journey of breathed air: 4. the air flows down the trachea 5. then it reaches the bronchi, two large tube-like passageways, each of which leads to one of the two lungs 6. the air continues on into smaller and smaller passageways called bronchioles 7. the air reaches the alveoli, the millions of minute and bunched together air sacs (alveoli are air sacs which are seemingly covered in nets of tiny capillaries 8. at the alveoli, an exchange of gases occurs, which will be explained in the next slide. Notice how the lungs contain many tubes called bronchioles that branch out from the bronchi The Respiratory System: How oxygen taken in; carbon dioxide removed This exchange of gases is carried out at the alveoli (small sacs of air) In a normal, properly functioning healthy lung there exists around 350 million of these alveoli How is oxygen switched with carbon dioxide? The carbon dioxide diffuses across the alveoli’s membrane and into the air sac to be exhaled The inhaled oxygen in the alveoli’s air sac diffuses across the membranes the Above is a an alveoli. The (blue) blood arriving is other way- into the oxygen-deprived. At the alveoli, oxygen diffuses into the bloodstream to be circulated blood and carbon dioxide diffuses out. This leaves the throughout the body blood replenished with oxygen as it leaves (red). The Excretory System: Standards MENU Standards: – a. Students know how the complementary activity of major body systems provides cells with oxygen and nutrients and removes toxic waste products such as carbon dioxide – g. Students know the homeostatic role of the kidneys in the removal of nitrogenous wastes and the role of the liver in blood detoxification and glucose balance The Excretory System: Introduction This system is made up of the: – Skin – Lungs – Kidneys (main organs of the excretory system) – And the organs that are related/connected in function to them The image above shows oxygen and nutrients absorbed by cells, while wastes are passed out to be taken care of by the excretory system. Next to it is a chart which matches wastes with its various associations. Why do we need an excretory system? – Human body needs this system to carry out homeostasis, (process constantly being carried with goal of an internal balance within the body. – excretory system promotes this healthy balance by removing from the body toxic and/or harmful waste in various ways as discussed in the following slides… The Excretory System: Skin and Lungs Skin – Excretes sweat out of the body through its numerous sweat pores Contained in the sweat is: – extra or excess water and salt – a little urea (a toxic compound that forms resulting from amino acids being used for energy) Above is an image depicting the lungs, where wastes as carbon dioxide are removed from the bloodstream. The red arrow points to a sweat gland which secretes waste, when necessary, through the sweat pore at the surface. Lungs – The lungs excrete carbon dioxide, which is produced as a waste product resulting from energy capturing from compounds in foods The Excretory System: Kidneys The two kidneys are the main organs of the excretory system. What do they do? – Waste-filled blood flows into the kidney through renal artery (arteries carry blood away from heart) – In kidney, the wastes including excess water, salts, urea filtered out – The cleansed blood then continues to circulate onward, leaving the kidney through the renal vein Above at the left is a labeled diagram of a kidney, where blood filtering takes place. – Wastes that include urea, salts, water, and others flow down the ureters to At the right is the actual urinary system the bladder and then are released from which shows the location of the two the body in urine through the urethra kidneys and other components. The Excretory System: Homeostatic Function of Kidneys So, in exactly what ways do the kidneys maintain the stable internal balance achieved by homeostasis? They… – Maintain and control the amount of water in the blood which directly correlates with blood volume – Maintain a specific pH for blood – Prevents waste from accumulating by taking them out of the bloodstream and then out of the body Those functions are extremely important because a person can be in a fatal condition in the event of damage or disease affecting the kidneys In that case, one would need to either get a new transplanted kidney from a donor (the ideal, but difficult to get solution) or undergo dialysis. A kidney dialysis machine, though time consuming for a patient, works similar to a kidney and cleanses blood to keep the person alive. Man hooked up to kidney dialysis machine The Endocrine System: Standards Standards: c. Students know how feedback loops in the nervous and endocrine systems regulate conditions in the body g. Students know the homeostatic role of the kidneys in the removal of nitrogenous wastes and the role of the liver in blood detoxification and glucose balance i. Students know how hormones (including digestive, reproductive, osmoregulatory) provides internal feedback mechanisms for homeostasis at the cellular level and in whole organisms MENU The Endocrine System: Introduction This system is made up of: Hormone producing, ductless glands The endocrine system’s glands are illustrated at the right. These glands are necessary to control the rate of metabolism of a body, rate or growth, and sexual development/ function. All are controlled by a feedback mechanism that maintains the balanced condition of homeostasis in response to both outside and inside stimulus. The Endocrine System: Feedback Mechanisms Control Function Hypothalamus, a part of the brain, will This flow chart demonstrates one of the feedback systems that helps control the amounts of hormone in response to cold. sense if there is excessive or too little amounts of hormones in the blood and signal the pituitary glands to produce more or less of trophic, or gland-stimulating, hormone If a gland is making too much of a hormone: Pituitary gland signaled by hypothalamus to produce less trophic hormone to normalize situation If a gland is making too little of a hormone: Pituitary gland signaled by hypothalamus to produce more trophic hormone to normalize situation The Endocrine System: Glands and Parts (1) Pituitary Gland Connected to hypothalamus Nine different hormones are secreted by this gland- these function to maintain bodily functions and keep under control some of the other glands that are part of the endocrine system Hypothalamus (NOT A GLAND) Part of the brain that controls the functions and actions of the pituitary gland Location and parts of the pituitary gland and hypothalamus The Endocrine System: Glands and Parts (2) Thyroid Gland The location of the thyroid and parathyroid glands in the neck. Controls and maintains body metabolism Produces thyroxine, a hormone, in a carefully controlled manner to maintain level of metabolism of (most of the) cells all around the body Parathyroid Glands There are four of these glands Produce hormones, along with the thyroid gland, that regulate calcium levels in the blood for homeostasis The Endocrine System: Glands and Parts (3) Adrenal Glands Responsible for regulating some kidney function and secreting hormones that prepare a person for stressful situations (which may call for a, for instance, “fight of flight” response Adrenal gland as seen under high magnification The adrenal glands are located right on top of the kidneys. The Endocrine System: Glands and Parts (3) Pancreas (NOT A GLAND) Secretes insulin, glucagon to maintain healthy blood sugar (or glucose) levels The pancreas’ location is shown here. (It also has functions in the digestive system as shown by its proximities and connections. Reproductive Glands (Gonads) Male Testes- make sperm Female Ovaries- make eggs (also known as ova) The Endocrine System: Liver Anatomy of the liver Liver – some of its functions allow it to be considered a member of the endocrine system Blood detoxification Liver gets blood from the intestines that contains many nutrients, but along with that toxins and chemicals that are potentially harmful Before this blood can re-enter the circulatory system, the liver cleanses out those toxins and therefore plays a key role in cleaning the blood This is why liver failure or poor function is devastating to healthy function; the liver prevents waste accumulation Glucose balance When there is too much glucose in the blood then the body’s cells need, the liver converts the glucose into glycogen, which it stores When glucose is needed, then, (under stimulation from hormones), the liver will reconvert the glycogen back into glucose and release the glucose back into the bloodstream for cell’s use Other balancing acts Controlling and maintaining other items, such as amino acids Works constantly to clear poisonous substances such as alcohol Makes proteins The Digestive System: Standards Standards: a. Students know how the complementary activity of major body systems provides cells with oxygen and nutrients and removes toxic waste products such as carbon dioxide f. Students know the individual functions and sites of secretion of digestive enzymes (amylases, proteases, nucleases, lipases), stomach acid, and bile salts MENU The Digestive System: Components This system is made up of: Mouth Esophagus Stomach Liver Pancreas Gallbladder Small and large intestines The main function of the digestive system is to change the foods humans eat into much smaller molecules that cells can actually absorb and use. The following slides takes this process step by step by location… The Digestive System - The Process of Digesting: #1 The Mouth Mouth – the first step of the digestive system Teeth Carry out the “physical” work of initial digestion They are bones that have their bases attached to the jaw bone, but are much stronger than regular bones so as to give them the ability to grind up food as thoroughly as possible into small pieces Salivary Glands Controlled by the nervous system to secrete saliva that aids in moistening the food to help the person chew easier Saliva contains amylase- enzyme that breaks down starch Saliva also contains lysozyme- enzyme that counters infection by destroying bacteria’s cell walls The Digestive System - The Process of Digesting: #2 The Esophagus After being chewed up, a clump of food is then called a bolus This bolus is pushed down into the throat and down into the esophagus In the esophagus, the bolus is not gravitationally drawn toward the stomach, but instead, the esophagus carries out contractions called peristalsis, which gradually squeezes the bolus down into the stomach The multi-image graphic at the right shows the relative location of the esophagus and depicts how peristalsis works To see a short video following a bolus down the esophagus into the stomach, click here and click on the large image on the page. The Digestive System - The Process of Digesting: #3 The Stomach The food that has been consumed now enters the stomach which continues digesting it Chemical Digestion The lining of the stomach contains Glands that make mucus that function to lubricate and thus prevent damage to the stomach wall Glands that make hydrochloric acid (or stomach acid), a very acidic acid which thereby makes the stomach a very acidic place and the enzyme nuclease, which works on breaking down nucleic acid into smaller nucleotides Presence of hydrochloric acid activates pepsin, an enzyme that, with hydrochloric acid, begins the process of digesting proteins A labeled Mechanical Digestion stomach. Notice Since the stomach is a hollow muscular organ, it is able to churn the multiple strong the fluids and food contents within it muscle layers/ This produces chyme, the mixture of such stomach fluids and food After about 1-2 hours, the pyloric valve, which, when closed prevents stomach content from spilling into the small intestine prematurely, opens and chyme can then enter the small intestines The Digestive System - The Process of Digesting: #4 The Pancreas From the stomach, chyme enters the duodenum, the first section of small intestines where a significant amount of chemical digestion occurs: The Pancreas Is a gland that makes Enzymes that help disintegrate carbohydrates, nucleic acids, proteins, lipids – these include… Amylase, which works on breaking down starch Protease, which works on breaking down protein Trypsin (an example of a protease), which works on breaking down protein Lipase, which works on breaking down fat This diagram shows the location of the pancreas. Ducts in the pancreas pass enzymes into the duodenum The Digestive System - The Process of Digesting: # 4 (continued) The liver and its generalized processes are depicted above. The Liver From the stomach, chyme enters the duodenum, the first section of small intestines where a significant amount of chemical digestion occurs: The Liver Makes bile salts (bile is a fluid that contains a lot of lipids and salts, which separates, and dissolves droplets of fat so that enzymes can get to them) Bile salts are then stored in the gall bladder to be released into the duodenum through the bile duct The Digestive System - The Process of Digesting: #5 The Intestines (Small and Large) Small Intestines Approximately three meters long- a lot longer compared to the initial duodenum When chyme enters this organ, chemical digestion is pretty much complete Villi, tiny protruding structures, absorb the nutrient molecules in the chyme as the muscles contract to move the chyme along The capillaries in the villi absorb the materials that resulted from carbohydrates and protein digestion Some fatty acids and undigested fat molecules are also absorbed into lacteals, which are lymph vessels This is an electron micrograph of villi in the small intestines Large Intestines What was once food is now nutrient-less matter that passes into the large intestines Through the large intestines, solid waste (unneeded by the body or excreted if recognized to be harmful or toxic) is passed out of the body Location of the small and large intestines The Reproductive System The primary function of the reproductive system is to help ensure the continual survival of a species, in this case, humans What makes this system one of the most, if not the most vital system for the human race? The reproductive system is responsible for making, holding, and releasing gametes, specialized cells. The male gamete is called the sperm and the female gamete is called the egg. When fertilization occurs, that is, a sperm successfully makes contact with an egg and enters it to fertilize it, a zygote is produced. From the zygote, the single fertilized egg, a baby soon develops. MENU The Reproductive System: Hormones Primary reproductive organs are called gonads • In the Male they are the testes Releases male sex hormone: testosterone • Produces sperm • Promotes male physical characteristics and development Sperm cells • In the Female they are the ovaries Releases female sex hormones: estrogen, progesterone • Estrogen Needed for eggs to develop Promotes female physical characteristics and development • Progesterone Egg cells Readies the uterus for developing embryo The Reproductive System: Fertilization This is an electron micrograph showing that several sperm have succeeded in reaching the egg. However, only one will be successful in actually fertilizing the egg. If an egg is located in a female’s Fallopian tube (there are two of these connected to the upper region of the uterus) chances are good that it will be fertilized in the presence of sperm Only about 1% of sperm ever reach the egg cell and only one may fertilize the egg cell As soon as the single sperm attaches to the egg, it enters and conjoins its nucleus with the egg’s (after the breakdown of the nuclear membranes of both gametes) Now the egg has been fertilized. The Reproductive System: Embryonic Development From the singled celled zygote, or fertilized egg, the cell continues to divide. In the animation to the right, the first six weeks from fertilization are depicted. (If the animation is not working click on it.) The wall-like place that the embryo is seen implanting itself is the uterine wall of the pregnant woman. Eventually, after about 9 months following fertilization, the fetus (what the embryo is called after more than eight weeks) has been prepared physically for birth. Contractions of the uterus, in which the baby has been in for almost all of the woman’s pregnancy, forces the baby out into the world to begin its life as a new human being. Early development from zygote to (early) embryo A newborn baby The Immune Response System: Standards Standards: Organisms have a variety of mechanisms to combat disease. As a basis for understanding the human immune response: MENU a. Students know the role of the skin in providing nonspecific defenses against infection b. Students know the role of antibodies in the body’s response to infection c. Students know how vaccination protects an individual from infectious diseases d. Students know there are important differences between bacteria and viruses with respect to their requirements for growth and replication, the body’s primary defenses against bacterial and viral infection, and effective treatments of these infections e. Students know why an individual with a compromised immune system (for example, a person with AIDS) may be unable to fight off and survive infections by microorganisms that are usually benign f. Students know the roles of phagocytes, B-lymphocytes, and Tlymphocytes in the immune system The Immune Response System: Components This system is made up of: The cells and proteins that work together to protect the body from Any suspected microorganisms (examples: viruses, fungi, bacteria) that may be harmful and infectious Main Body Structures (External) Eyes Nose Mouth Respiratory tract Stomach and intestines Genitourinary system Skin The Immune System: Nonspecific (or Innate) Immunity If the skin, a major defense, is broken the inflammatory response takes effect… This is the nonspecific and quickly- responding immune response that humans are born with and includes.. Barriers (both chemical and physical) The skin is the first defense against pathogens Inflammatory response occurs if pathogen gets past skin Blood vessels by open wound enlarge to allow the white blood cells to leak into the tissue that is infected Phagocytes White blood cells that engulf a recognized foreign body and then digest the foreign body with enzymes (within the cell’s lysosomes) Interferons Notice how the inflammation Virus-resistant proteins (acts to slow virus to functions to allow pathogen and allow more time for the immune system to foreign body fighting white blood respond) cells into the affected tissue. The Immune System: Humoral Immunity Provides bacterial defense Recognition process: since there are so many varieties of B-lymphocytes, only some will be stimulated by antigens. T-lymphocytes help to keep a control on this process to ensure workings These T-lymphocytes, or helper T cells help Blymphocytes, or B cells become antibody making plasma cells which produce many antibodies to counter the bacteria Antibodies, in the future, will respond to the same antigen to disable them A close-up view of a T-lymphocyte Phagocytes engulfing bacterium to initiate the humoral immunity process. The Nervous System: Vaccination This is one of the ways a person can strengthen their immune systems to protect them better How it works Weakened or dead microorganisms (responsible for causing a specific disease such as measles or influenza, etc.) are introduced to the body Those microorganisms are not strong enough to cause disease, but do trigger an immune response that makes antibodies against the microorganism In a future exposure to the microorganism, those antibodies will be Vaccination is important because it helps a human’s body be better prepared for activated and counter the microorganism countering harmful disease. effectively virus bacteria The Immune System: Virus vs. Bacteria Virus Are not alive, parasitic (depend on host for survival, replication Can lay dormant and be reactivated Replicates by using a cell it has entered, cell bursts and many more viruses emerge Body’s primary defense: white cells (macrophages) engulf viral particles, lymphocytes make antibodies countering virus Effective treatment: more difficult to fight a virus caused disease than bacterial; help patient’s symptoms and hope immune system strong enough (in some cases), immunization (sometimes) Bacteria Single-cell microorganisms (so are alive) Reduction (sometimes full) in strength after time Some are beneficial to humans Multiply and live in warm, wet conditions and cannot move on their own Reproduce much less rapidly then viruses because, as cells, they can only double in a given time period Body’s primary defense: enzymes and acid which kill bacteria, white blood cells engulf them, antibodies Effective treatment: improve hygiene, immunization For Venn Diagram (that is not made by this powerpoint author) view the next slide… Venn Diagram: Comparing Virus and Bacteria The Immune System: Disorders and Consequences Allergies Allergy inducing antigen attach to mast cells, (which are common in the body’s nasal passage) The mast cells are then stimulated to make histamines, a chemical that causes the irritations that result from allergies. Autoimmune Disease Occurs when the immune system mistakes the bodies cells for its enemies AIDS (Acquired Immune Deficiency Syndrome) which makes person’s immune system dysfunctional; they will contract illnesses normally easily fended off by healthy immune system In this case, the women’s allergies are perhaps caused by allergens in her pet’s hair. Structure of an HIV virus which is the cause of AIDS. The Human Body: Systems Menu Nervous System Reproductive System Circulatory System Skeletal System Immune System Are you sure? EXIT Yes No Digestive System Endocrine System Muscular System Excretory System Integumentary System Respiratory System THE END