Presentation on theme: "AP Biology Human Body Systems Project"— Presentation transcript:
1 AP Biology Human Body Systems Project Jeff Zhang
2 Table of ContentsDigestive System Circulatory System Respiratory System Immune System Excretory System Muscular System Skeletal System Senses System Endocrine System Reproductive System Nervous System
3 Digestive SystemThe digestive system is responsible for breaking down and converting food into energy.
4 Mouth Beginning of the digestive system Chewing breaks food into pieces that are easier to digest
5 Pharynx Receives food after it’s swallowed Passageway for food and air Opens and closes tracheaAverage: 5 inches long (http://www.medicinenet.com/nasopharyngeal_cancer/article.htm)
6 Esophagus“Channel” that food travels from the mouth to the rest of the digestive systemPeristalsis – Muscular contractions that move food down
7 Stomach“Container” that stores and breaks down food with enzymes and hydrochloric acidProcessed food becomes “usable” and absorbed into the body
8 Small IntestineDuodenum – Mixes enzymes produced by the pancreas and liver to break down foodJejunum and Ileum - Absorb nutrients into the bloodstreamAverage: 22 feet long (http://kidshealth.org/kid/htbw/digestive_system.html)
9 Large Intestine Also called the “colon” Average: 6 feet long (http://my.clevelandclinic.org/anatomy/digestive_system/hic_the_structure_and_function_of_the_digestive_system.aspx)Divided into Ascending (right) colon, Transverse (across) colon, and Descending (left) colonResponsible for processing waste to be removed from the body
10 Rectum Connects large intestine to the anus Holds stool until released Average: 8 inches long (http://www.colonrectal.net/cancermanagement.htm)
11 Anus Final part of digestive system Internal and External Anal SphinctersReleases stoolAverage: 2 inches long (http://www.sharecare.com/question/role-of-anus-in-digestion)
12 Salivary Glands First part of chemical digestion First part of chemical digestionProduces saliva to help form the bolus (“ball” of chewed food) and begin digestion of food
13 LiverMain function is to process nutrients absorbed in the small intestineProduces certain blood plasma proteinsDetoxifies alcohol and ammoniaBreaks down drugsProcess hemoglobin and stores ironProduces biliverden and bilirubenRegulates blood clotting(http://medicalcenter.osu.edu/patientcare/healthcare_services/liver_biliary_pancreatic_disease/liver_anatomy_function/Pages/index.aspx)
14 Pancreas Breaks down proteins, carbohydrates, and fats Secretes insulinProduces chemicals that help neutralize stomach acidsAverage: 6 inches long (http://www.idph.state.il.us/cancer/factsheets/pancreatic.htm)
15 GallbladderStores and releases biliverden and biliruben into the duodenum to help digest fats (http://www.gallbladderattack.com/gallbladder.shtml)
16 Sphincters Controls the release of food from one organ to another Includes: Pyloric Sphincter, Ileocecal Sphincter, Urethral Sphincter, Glisson’s Sphincter, and the Internal and External Anal Sphincters (http://answers.yahoo.com/question/index?qid= AAZavwQ)
18 Digestion of Large Molecules Large food molecules have to be broken down into smaller parts to be able to be digestedFood is broken down and “rearranged” into a form that humans can use – The parts we can’t use are excreted as wasteEnzymes play a crucial role in the digestion of large food moleculesOnly food small enough to be absorbed by the villi of the small intestine is used as nutrition by the human body(http://www.ibguides.com/biology/notes/digestion)
19 Role of EnzymesEnzymes dramatically increase the rate at which food is broken downAmylase breaks down carbohydratesProtease breaks down proteinsLipase breaks down fats (lipids)(http://wiki.answers.com/Q/What_are_the_functions_of_amylase_protease_and_lipase)
20 Physical, mechanical digestion of food through movement Physical DigestionPhysical, mechanical digestion of food through movementBeginning digestionSubstances stay the same, just smaller piecesChemical DigestionChemical digestion of food through acids and enzymesNecessary to further digest food into finer parts“Transforms” substances into different proteins and sugarsBoth break down larger food molecules into smaller pieces that can be digested by the body
21 Digestion of Carbohydrates, Proteins, and Lipids Carbohydrates and proteins are digested in the stomach by amylase and protease, respectively, produced by the pancreas and small intestineLipids can’t be digested by the stomach alone – Primarily broken down in the duodenum by lipase produced by the small intestine and liver (http://www.mmeade.com/cheat/digestion.html)
22 Ulcers A weakening in the lining of the stomach or small intestine. Pain in the abdominal region is caused by stomach acid eroding nerve endings.Up to 10% of Americans will develop ulcers sometime in their lives.Treatment is with antacids and/or antibiotics if caused by bacteria.(http://www.symptomsofstomachulcer.org/)
23 GallstonesExcessive amounts of cholesterol in the bile ducts can crystallize and form gallstones.Inflammation in the small intestine and severe abdominal pain are common symptoms.About 10% of the population has gallstones, but only 1-2% of the population exhibits symptoms that require medical careTreatment: Extracorporeal shockwave lithotripsy can generate shockwaves that break gallstones apart into small pieces that pass easily though the bile system(http://gallstones.com/)
24 Circulatory System Consists of blood, the heart, and blood vessels The Circulatory System transports nutrients to cells, removes waste from cells, and transports gasses to and from the lungs.
25 Structure and function of blood vessels Arteries carry blood from the heart to the rest of the bodyCapillaries connect arteries and veinsVeins return blood back to the heartBlood vessels have three layers of tissue:Innermost – Tunica Interna: smooth surface that provides a low-friction channel for blood flowMiddle – Tunica Media: smooth muscle tissue that controls contraction and relaxation of blood vesselsOutermost – Tunica Adventia: connective tissue that creates a barrier to prevent blood from diffusing into other parts of the body and keep oxygen and nutrients in(http://www.fi.edu/learn/heart/vessels/vessels.html)
26 Route of BloodLeft ventricle, aortic valve, aorta, peripheral arteries, arterioles, capillaries, venules, peripheral veins, vena cava, right atrium, tricuspid valve, right ventricle, pulmonary valve, pulmonary artery, pulmonary capillaries, pulmonary veins, left atrium, mitral valve, and left ventricle.Blood valves ensure the flow of blood goes the intended (one-way) direction.Tricuspid valve allows flow into the Right Ventricle from the Right AtriumMitral valve allows flow into the Left Ventricle from the Left AtriumAortic valve allows flow into the Aorta from the Left VentriclePulmonary valve allows flow into the Pulmonary Artery from the Right Ventricle(http://www.dummies.com/how-to/content/the-path-of-blood-through-the-human-body.html)
27 Composition of bloodBlood is composed of plasma, erythrocytes, leukocytes, and plateletsPlasma is the fluid that carries blood cells, gases, and nutrients to and from cellsErythrocytes (red blood cells) carry oxygen to body cellsLeukocytes (white blood cells) protect the body from invading pathogensPlatelets clot blood and reduce the amount of blood lost when the body is cut or wounded(http://anthro.palomar.edu/blood/blood_components.htm)
28 ErythrocytesThe primary function of erythrocytes is to deliver oxygen from the lungs to other cells in the bodyThey demonstrate how structure influences function because the shape of the cell includes “indents” that allow it to carry and transport oxygen molecules(http://anthro.palomar.edu/blood/blood_components.htm)
29 Open and closed circulatory systems All vertebrates, and a few invertebrates, have closed circulatory systems – Example: HumansMost invertebrates have open circulatory systems – Example: crabsClosed: Blood is closed at all times within blood vessels and pumped by the heart through vessels not filling body cavitiesOpen: Blood is pumped by the heart into body cavities where tissues are surrounded by blood(http://www2.gsu.edu/~bioasx/closeopen.html)
30 Fish circulatory system 2-chambered heart that completely separates oxygen-rich and oxygen-depleted bloodSingle loop path that takes blood from the heart to the gills and then to the body
31 Amphibian circulatory system 3-chambered heart with two atria and one ventricleBlood moves from the heart to the pulmonary capillaries where gas is exchanged and then returned to the heartSome of the blood returned to the heart goes to the pulmonary circuit, some to the systemic circuitMixes oxygen-rich and oxygen-depleted blood
32 Reptile circulatory system 3-chambered heartOne ventricle, two aortasSome have partial separation of systemic and pulmonary circuits, others complete separationVariations in blood flow allow deoxygenated blood to be returned to the body or oxygenated blood to be returned to the lungs, if needed
33 Mammal circulatory system 4-chambered heartTwo atriums, two ventriclesSeparation of systemic and pulmonary circuitsMammalian red blood cells lack a nucleus to maximize oxygen transport
34 Bird circulatory system 4-chambered heartSeparation of systemic and pulmonary circuitsArranged for optimal blood transport – Birds have hearts that are proportionally 3 times larger than mammals and beat 5 to 6 times as fast
35 AtherosclerosisAtherosclerosis is the hardening of the arterial wall due to the build up of plaque.Symptoms include decreased or stopped blood flow and sharp pain. Sometimes the first sign is a heart attack.About 11.5% of the population has some coronary artery diseaseTreatment: Statins drugs to lower cholesterol reduce build-up of plaque(http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH /)
36 Hypertension Commonly known as high blood pressure Most people show no signs, though headaches and dizziness may be a resultHigh blood pressure increases the chances for heart attacksThe incidence in US adults is about 30%Treatment: Exercise and a diet low in sodium and fats reduce the risk of heart disease(http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH /)
37 Respiratory SystemThe respiratory system is in charge of supplying blood with oxygen to deliver to body cells
38 AlveoliAlveoli are at the ends of each pulmonary vein and are the places where gases are exchanged.The total surface area they provide is about 100 square meters.Alveolar tissue is made of elastic fibers and allows the alveoli to stretch and compress.Capillaries cover 70% of the area and gases readily pass through the thin membranes.(http://biology.clc.uc.edu/courses/bio105/respirat.htm)
39 Carbon Dioxide and Oxygen Red blood cells contain hemoglobin which binds to oxygen molecules. They carry the oxygen to other cells in the body and trade it for carbon dioxide molecules, which they bring back to the lungs. (http://www.bio.davidson.edu/courses/molbio/molstudents/spring2005/heiner/hemoglobin.html)One red blood cell can carry four oxygen molecules at a time.Path of oxygen: Air > mouth/nose > pharynx > larynx > trachea > lung > bronchi > bronchioles > alveoli > pulmonary capillaries > hemoglobin (http://www.fi.edu/learn/heart/systems/respiration.html)
40 Inhalation and Exhalation Inhalation is the process of taking air into the lungs. The diaphragm contracts to expand the thoracic cavity and increase the volume. This causes the air pressure inside the lungs to be lower than the air pressure outside, so air moves into the body.Exhalation is the process of expelling air from the lungs. The diaphragm relaxes and decreases the volume of the thoracic cavity. The air pressure inside the lungs is now greater than that of the outside of the lungs, and air leaves the body.
41 Asthma Bronchial airways are too narrow Coughing, wheezing, and difficulty breathingFor adults, the incidence of asthma is about 16%Treatment: Bronchodilators relax airway passages(http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH /)
42 TuberculosisTuberculosis is an infectious disease caused by the bacteria Mycobacterium tuberculosisThe bacteria causes lesions to form on the lymph nodesPrevalence in the United States is about 3.6 cases per 100,000 individuals, though the incidence rate is far higher for areas of Africa and AsiaTreatment: Combinations of antibiotics are usually successful in curing the disease(http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH /)
43 Immune SystemThe function of the immune system is to protect the body from disease.
44 Major OrgansBone marrow – Creates B cells, granulocytes, T cells and thymocytes for the immune system through hematopoiesisThymus – Produces lymphocytes and mature T cellsSpleen – Filters blood and traps foreign microorganisms for destructionLymph nodes – Filter interstitial fluid between body cells to destroy antigens(http://www.buzzle.com/articles/organs-of-the-immune-system.html)
45 Recognition of Pathogens All cells have specific markers on their surface that the immune system can recognize as “self” or “non-self.”Antigens are certain markers that cause an immune response. The immune system produces antibodies that bind to antigens and signal for immune system cells to destroy the foreign microbe.(http://www.cs.unm.edu/~immsec/html-imm/introduction.html)
46 Specific defense adaptations Innate ImmunityNonspecific defenseIncludes physical barriers to infection such as skin, blood chemicals, and immune system cellsAcquired ImmunitySpecific defense adaptationsNew antigens are recognized and new antibodies are created to mark harmful microbes to be attacked by immune system cellsi.e. Chicken pox immunityBoth are ways that the immune system protects the body from infectionImmune system cells inevitably are the ones that actively destroy the foreign cells
47 The body forms antibodies in response to antigens Active ImmunityThe body forms antibodies in response to antigensThe immune system “remembers” antigens and how to respond to themi.e. VaccinationsPassive ImmunityNot made by the individual, passed down to them or transferred artificiallyi.e. mothers’ immune systems protect their developing child in the wombBoth are ways that the immune system is able to respond to infection
48 Cell-Mediated Immunity Humoral ImmunityAntigen-specific B cells play the central roleAntibody-mediated specific immunityInvolves body fluidsCell-Mediated ImmunityAntigen-specific T cells play the central roleDoes not involve antibodiesInvolves cellsBoth are responses by the adaptive immune systemT cells activate humoral B cells to produce antibodies
49 B and T LymphocytesB Lymphocytes are produced in bone marrow and are activated by helper T cellsT Lymphocytes are produced in the thymus and activated by specific MHC proteinsB lymphocytes identify pathogens and produce antibodies to mark them to be attacked by T cells(http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/B/B_and_Tcells.html)
50 Antibiotics Bacteria are alive, while viruses are not Antibiotics are meant to destroy bacteria by rupturing their cell walls; viruses don’t have cell walls and are parasites inside body cells, so antibiotics can’t touch themViruses are effectively “complicated molecules” that can reproduce themselves – They can’t be “killed”(http://health.howstuffworks.com/medicine/medication/question88.htm)
51 Autoimmune DiseaseThe immune system attacks “self” tissues in the body that are necessary for proper function of organ systemsVarious symptoms such as organ failure, fevers, difficulty breathing, etcIncidence is very low, but usually fatalTreatment: Immune suppressants, but leave the body susceptible to disease(http://www.niams.nih.gov/health_info/Autoimmune/default.asp)
52 HIV/AIDSAcquired Immunodeficiency Syndrome caused by the Human Immunodeficiency VirusHIV attacks T cells and other cells of the immune system, making the body more susceptible to other diseasesIncidence is disproportional – African Americans and homosexuals make up more than half of all cases in the United StatesCurrently about 1.5 million people in the US have the virus, with about 56,000 new infections each yearTreatment: Reverse transcriptase inhibitors can slow the spread of the virus(http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH /)
53 Excretory SystemThe function of the excretory system is to remove excess or unwanted waste materials from an organism.
54 Nitrogenous WastesAmmonia – The most efficient form of nitrogen waste and a gas. Most aquatic animals excrete waste this way because ammonia readily diffuses through membranes into the water.Urea – A liquid with very low toxicity, almost 100,000 times less than Ammonia – Amphibians, mammals, and some fishesUric Acid – Most energetically expensive form of waste and is a thick “paste” that is largely insoluble in water – Most reptiles, birds, and arthropods(http://ex-anatomy.org/nitro.html)
55 NephronRenal corpuscle – Collects and moves urine, secretes waste products to form urineProximal convoluted tubule – Filtration and reabsorption waterLoop of Henle – Regulates water and solute balance of urineDistal convoluted tubule – Reabsorbs additional water until the final concentration of urine is approximately equal to that of the other body fluids; responsible for excretion of urine(http://www.answers.com/topic/what-are-the-major-parts-of-the-nephron)
56 ProteinuriaUrine contains an abnormal amount of protein – Proteins aren’t filtered out of the urine and are excreted as wasteFoam urine, swelling in the hands, feet, and faceVery rare in healthy individuals; incidence rate is much higher for those with high blood pressure and/or diabetesTreatment may include blood glucose and blood pressure control and a change in diet(http://kidney.niddk.nih.gov/kudiseases/pubs/proteinuria/)
57 Kidney DiseaseLoss of kidney function either due to injury or organ failure over timeDangerous accumulation of waste in the body, anemia, high blood pressure, and acidosisApproximately 10% of Americans ages 20 years and older develop some form of kidney diseaseTreatment includes dialysis and changes in diet. Kidney failure, if detected early enough, is usually reversible(http://www.emedicinehealth.com/chronic_kidney_disease/article_em.htm)
58 Muscular SystemThe function of the muscular system is to allow movement, maintain posture, and circulate blood throughout the body.
59 The Three Types of Muscle Tissue Skeletal muscle occurs in muscles attached to the skeleton that allow for movementCardiac muscle is in the heart and under involuntary control as it pumps bloodSmooth muscle forms the walls of hollow organs and is also under involuntary control
60 Skeletal Muscle Contraction The sliding filament theory involves bind-and-release impulses that cause myosin to move along the filament and forcing thick filament to move over thin filament. After an impulse is sent from the brain, calcium channels in the muscular axon open and calcium ions move in to cause the release of acetylcholine. Acetylcholine acts as a transmitter that attaches itself to receptors in the sarcomere. This triggers an action potential that causes the release of calcium ions from the sarcoplasmic reticulum. These ions trigger actin sites and the ions begin binding to troponin. Tropomyosin is released and then blocks the binding of actin which causes the muscle to contract. The troponin that is formed prevents some of the blocking action of tropomyosin and some myosin heads attach to active actin sites. These myosin heads form cross bridges using ATP. The ATP is broken into ADP and phosphates which cause the myosin to detach from the actin sites and hydrolyze ATP. This recharges the myosin to repeat the process. This bind-and-release action causes muscle contraction.
61 Muscular DystrophyMuscular dystrophy is a series of more than 30 genetic diseases that cause the degeneration of skeletal muscles that control movementPrimarily affecting males, by the age of 12 victims usually cannot walk and need respirators to continue breathingThe disease is very rare; females carrying the gene have a 50% chance of passing it to their childrenThere is no treatment to stop or reverse muscular dystrophy – There is only physical and speech therapy and respiratory assistance
62 Myasthenia gravisAn autoimmune neuromuscular disease, the immune system produces antibodies that block muscle cells from receiving signals from nerve cellsMyasthenia gravis causes severe weakness of voluntary muscles and can result in trouble breathing and walkingIncidence is about 1 in 500,000Very little is known about the disease. Current treatment is lifestyle changes such as rest and avoiding stress and heat.
63 Skeletal System The skeletal system has six major functions: Support ProtectionAiding in MovementStorage of MineralsProduction of Red Blood CellsChemical energy storage(http://www.buzzle.com/articles/skeletal-system-functions.html)
64 Human MovementBones fit together at joints, which allow pivotal movementLigaments connect bones together and can stretch to allow movementMuscles move bones by extending or flexing a jointTendons attach muscles to bones
65 Hydrostatic SkeletonHydrostatic skeletons consist of fluid under pressureThis type of skeleton is common among worms and higher invertebrates such as hydras, planarians, and segmented worms
66 ExoskeletonMost aquatic animals and some terrestrial animals (insects) have rigid skeletons on the outside of their bodyUsually made from chitinAnimal must shed its skeleton and form a new one when it outgrows its old oneExample: Beetles
67 Endoskeleton Animal skeletons are endoskeletons Consists of bone and cartilage made from calcium and grows with the animalVertebrates have this skeleton, but some invertebrates such as sponges, sea stars, and sea urchins have endoskeleton plates underneath their skin
68 Osteoporosis Osteoporosis is the most common skeletal disease Bones become weaker from a lack of calcium and break easily1 in 5 women over the age of 50 develop the diseaseTreatments include medication, pain therapy, and lifestyle changes that prevent the risk of falls
69 ArthritisArthritis is the inflammation of one or more joints – There are over 100 different typesSymptoms include joint pain, swelling, reduced ability to move a joint, and stiffness.Many Americans face arthritis at some point in their lives, especially the elderlyTreatments include pain therapy, physical therapy, pain medication, and lifestyle changes.
70 Senses SystemThe function of the senses system is to give the body the ability to detect the outside world.
71 Sensory ReceptorsMechanoreceptors detect changes in pressure, position, and acceleration (nose, skin, ear)Thermoreceptors detect hot or cold temperatures (skin)Chemoreceptors detect ions and molecules (nose)Photoreceptors detect light (eyes)Pain receptors detect severe heat, pressure, and chemicals that harm the body (skin)
72 RhodopsinRhodopsin is a biological pigment of the retina that forms photoreceptor cells and perceive lightRhodopsin provides the ability for photoreceptor cells to signal to each other and the brain about light entering the retina
73 Endocrine SystemThe function of the endocrine system is to transmit hormones to regulate mood, growth, development, tissue formation, metabolism, and sexual reproduction.
74 HomeostasisThe primary function of the endocrine system is to maintain homeostasis – A state of internal stability in the body such as constant body temperature and constant water content.The hypothalamus causes the endocrine system to sustain homeostasis by ordering the secretion of enzymes
75 Negative FeedbackA negative feedback in the body is the process by which a change in the level of a certain chemical leads directly to a reduction in its formation, reduction in its absorption, or increase in its excretion.Cortisol is an example – Too much suppresses the immune system which causes a different chemical to be produced which shuts down production of cortisol temporarily.
76 Endocrine GlandsInsulin is one important hormone that endocrine glands produce.Insulin regulates glucose intake by helping it move from the blood into body cells
77 Type I and Type II Diabetes Both forms of diabetes involve a deficiency in meeting the body’s insulin needsThe incidence rates of both forms have increased in the past 30 yearsType I diabetes usually occurs in thinner individuals before the age of 20; Type II diabetics are usually overweight and over the age of 35Type I people can’t produce insulin because autoantibodies destroy glands in the pancreas that produce it; Type II people don’t produce enough insulin to sustain their body
78 Hyperthyroidism The thyroid gland produces too much thyroid hormone. Symptoms include fatigue, goiter, increased sweating, heat intolerance, weight loss, and restlessness.The incidence of hyperthyroidism is less than 1%Treatment includes antithyroid medication and possible surgery to remove the thyroid gland.
79 Reproductive SystemThe function of the reproductive system is to continue the survival of the species. It is the means by which the body can transfer genes from one individual to another.
80 Sexual Reproduction vs. Asexual Reproduction Both are ways for organisms to procreate their species.Sexual reproduction involves two organisms while asexual involves oneSexual reproduction produces diversity; asexual reproduction creates “clones”Hydras, sponges, and planarians are animals that exhibit asexual reproduction
81 SpermatogenesisSpermatogenesis occurs in the seminiferous tubules of the testes in malesPrimary spermatocytes undergo meiosis to form secondary spermatocytes, which also undergo meiosis to form 4 haploid spermatidsThese spermatids undergo a stage of metamorphosis to become mature spermatozoa
82 Oogenesis Oogenesis occurs in the ovaries in females Oogenesis begins with a immature primary oocyte that divides into a secondary oocyte and a smaller first polar bodyThe secondary oocyte produces a mature ovum and a small polar body while the first polar body creates two more smaller polar bodiesOogenesis creates one mature egg cell and three small polar bodies that go on to dieThese three polar bodies “donate” their cytoplasm and nutrients to the mature egg cell
83 Menstrual cycle vs. Estrous cycle Humans and the great apes follow the menstrual cycle, while the rest of the animal kingdom (the female half) undergoes the estrous cycleAnimals with the estrous cycle reabsorb the endometrium if conception doesn’t occur, while animals with the menstrual cycle shed the endometrium through menstruationAnimals with the estrous cycle are sexually active only during the estrous phase of the cycle, while animals with the menstrual cycle are sexually active at any time of the cycle
84 Menstrual cycle The menstrual cycle usually occurs over 28 days. The cycle starts with menstruation (the uterine cycle) where the endometrium is shed as the egg isn’t fertilized and the body prepares the way for a new eggThe follicular phase (the ovarian cycle) comes after as a follicle stimulating hormone (FSH) stimulates the lining of the uterus to grow. These follicles also secrete estrogen and initiate the formation of a new endometrium.The luteal phase (part of the ovarian cycle) occurs when the ovaries form the corpus luteum and release progesterone which readies the uterus for the implantation of the blastocyst.If there is no fertilization, menstruation occurs again and the egg is lost.The menstrual cycle is a feedback mechanism that is regulated by the presence of fertilization and the quantity of certain hormones.
85 DevelopmentThe fertilized ovum forms a “ball of cells” called a morula through the process of cleavage, where the zygote undergoes rapid cell divisionThis ball eventually expands and becomes hollow, called a blastulaGastrulation comes after and divides the body into three layers as outside ectoderm cells move inward to form the endoderm. This final three-layer ball is called the gastrula.Organogenesis is the final stage in early development as cells in each layer differentiate and form the organs of the human body
86 Germ LayersEctoderm is the outermost layer and forms the skin, nails, hair, sweat glands, facial muscles, and the brain and the spinal cord.The mesoderm is the middle layer and forms the heart, kidneys, bones, muscles, and blood vessels.Endoderm is the innermost layer and gives rise to the respiratory and digestive systems.
87 GonorrheaGonorrhea is a sexually transmitted disease that causes severe pain and infertilitySymptoms include swollen reproductive tracts, pain when urinating, and feversGonorrhea is the most common STD, but the incidence is less than 1% of the general populationTreatments include antibiotics and pain medications
88 SyphilisSyphilis is a sexually transmitted disease that can cause infertility and deathSymptoms include sores where syphilis entered the body, rashes, mucous discharge, fatigue, and finally damage to the heart, eyes, nerves, and brain.The incidence rate in the US among males 5.7 percentTreatments include antibiotics
89 Nervous SystemThe function of the nervous system is to coordinate and send signals from one cell to another and from one part of the body to others.
90 Central Nervous System and Peripheral Nervous System The central nervous system is the part of the nervous system that receives information and coordinate responses. It contains the brain and the spinal cord.The peripheral nervous system connects the central nervous system to the limbs and organs. It consists of the nerves and ganglia outside of the central nervous system.
92 Reflex arcA sensation is felt through the activation of a receptor and the sensory neuron relays signals to the brainThis signal is transported from the Peripheral Nervous System to the Central Nervous System and the brainThe brain responds by sending a signal from the CNS back to the PNSThis signal activates a motor neuron that causes the body to respond to the sensation
93 Major Parts of the Brain Cerebral Hemispheres perform high level functions such as thought, judgment, motion, interpretation, memory, and recognition.Diencephalon process sensory and motor information and relay it to the cerebrum. This region also contains the hypothalamus, which regulates involuntary functions, and the pituitary gland, which secretes hormones.Brain stem controls reflexes and helps the cerebrum communicate with the cerebellum. It contains the medulla oblongata which controls heart rate, blood pressure, and breathing.Cerebellum coordinates movement, balance, and coordination.
94 Nerve ImpulsesThe neuron begins with a concentration of Na+ ions outside of a neuron’s membrane and K+ ions on the inside. Pumps along the membrane create this polarized membrane potential. This state is known as the resting potential.When a stimulus reaches a resting neuron, the ion channels open along the action potential and Na+ ions rush inside the neuron and the region becomes depolarized. This, however, only occurs if the stimulus is able to exceed a threshold level and cause the channels to open.The ion channels begin allowing K+ ions to go outside to accommodate the Na+ ions inside. This causes the region to become repolarized.The refractory period begins as ion channels pump K+ ions back inside and Na+ ions outside. During this period, the neuron can’t respond to any stimuli and no action potential occurs.
95 NeurotransmittersNeurotransmitters are chemicals that transmit signals from one neuron to the next across synapses.Axon terminals release neurotransmitters from a pump that is received by receptors on the dendrites of another neuron.
96 Huntington’s DiseaseHuntington’s Disease is a hereditary disease that causes nerve cells to degenerateSymptoms include changes in behavior, irritability, forgetfulness, paranoia, loss of judgment and speech impairmentsPrevalence is about 1 in 10,000 peopleThere is no cure. Treatment is only to slow the disease. Dopamine blockers and certain drugs control behavior and may slow degeneration of gray tissue.
97 Multiple SclerosisMultiple sclerosis is an autoimmune disease that affects the brain and spinal cord.Immune system cells attack the myelin sheath that protects nerve cells. As nerve cells are damaged, nerve signals may slow down or stop.Symptoms include spasms, trouble moving, eye problems, pain, and slurred speech.Incidence is about 0.1% in the United StatesThere is no cure. Therapy can help slow the disease and regain speech and coordination.