Saturday, March 23, 1996
In animal respiratory systems, the three main points are the gas exchange, the method of delivery and the exchange organ. In simple animals, diffusion exchanges the gases. As creatures became bigger and/or more active the respiratory system became more complicated.
Earthworms still diffuse oxygen through the skin, but they use blood to reach the inner cells.
Fish for example have gills to collect oxygen. Their gills are lungs which are like modified skin. The fish takes a mouthful of water and pushes it past the gills. The water goes toward the tail while the blood goes toward the head. This is called counter current exchange this maximizes the exchange so that the diffusion can occur all the way through the system. The opposite of this is parallel current exchange. (Check Book for Picture)
Insects have a weird respiratory system named the tracheal system. This is where there are tubes that carry air to individual cells. These tubes limit the size of insects. (See Book for Picture)
The human system of "passageways and lungs" collects oxygen and gets rid of carbon dioxide. After passing through the nose or mouth, pharynx, epiglottis, and larynx, it goes down the TRACEA which leads to the lungs. Cilia an mucus collects foreign dust particles. The airways branch and branch until they reach little sacs called ALVEOLI which have one cell thick walls that diffuse O2 and CO2. Remember that the cells get oxygen from the blood and give back carbon dioxide which diffuses out of the lungs and in comes oxygen.
The diaphragm moves up and down forcing air in and out of the alveoli. The diaphragm is relaxed in a dome position and flattens as it contracts. The brain controls breathing in the medulla oblongata. This occures unconciously and is regulated by O2 and CO2 sensors with priority given to the CO2 ones. Refer to the handout and know the functions of the terms listed.
Human respiration can be broken down into two parts: taking in air, transporting the gases. The air arrives via the negative breathing pressure. By increasing the chest cavity volume, we decrease the pressure and air flows in. Exhaling is the opposite. The gas transport uses the circulatory system. The hemoglobin was originally not needed as we were very calm creatures. The hemoglobin takes oxygen to form oxyhemoglobin. This goes to the tissues and via a diffusive process, breaks down. The CO2 goes back by turning into a bicarbonate ion. (H2O + CO2 H2CO3 H+ + HCO3-) This transformation is reversed in the lungs to release carbon dioxide.
This system is different in different animals. It was required to transport stuff in multi-cellular animals. It must transport CO2, O2, nutrients, wastes especially nitrogen, and hormones the chemical messangers. It must consist of a pump and vessels. The liquid used to transport the stuff is calleed blood. It consists of mainly water but includes inorganic molecules especially ions, organic molecules and blood cells.
Circulatory systems can be catagorized into two general catagories, open and closed. The open system found in a grasshopper (P.780) and other arthropods has a dorsal blood vessel and heart which pumps blood on the brain. The blood then oozes through the tissues back to the heart. This circulation is slow, but these animals use trachea tubes for their gases. A closed circulatory system is foun in earthworms and more evolved creatures. These vessels are all connected to form a loop. In vertebrates, their circulatory system can further be catagorized by the chambers of their hearts. Fis have two, reptiles have three and mammals have four. The chambers are separate except for blue babies who by genetic defectt have a hole in between chambers. These chambers are termed atria which receive blood and ventricles which pump out blood. Valves prevent backflow in the system.
The pulse that you feel is literally the artery expanding and rebounding. This increases and decreases as your condition changes. Normally, at rest and especially lying in bed just after waking up, the pulse is constant and 60 BPM or lower. The pulse that increases when exercising does not continue to increase. The heart can first only beat so fast and the chambers can only take in so much blood so quickly to release it. The amount of blood that the heart pumps out in a minute is the cardiac output.
The blood is made of a watery solute called plasma which comprises 55% by volume. Red blood cells compries the 44% of the blood. These have no nucleus and only live for 120 days. Each cell has hemoglobin which contains iron and is a protein that collects oxygen. Hemoglobin can also carry carbon dioxide, but most carbon dioxide combines with sodium to fomr sodium hydrongen carbonate. White blood cells comprise 1% of the blood. Platelets prevent from bleeding to death by cloting blood.
Blood is catagorized into types depending on which antibodies (A or B) are present. Antigens are foreign substances that make the immune system respond. Antibodies are the things that react with antigens on the cell. (See Text P. 984 for picture on the A,B,AB,O Blood types. The Rh factor is the Rhesus factor which when the fetus's blood mixes with the mothers (being the opposite types of course) the antibodies form and the next baby's RBCs die from the antibodies.
Arteries carry blood away from the heart and a thick. The heart increases the artery pressure and you feel a pulse. The capillaries are the one cell thick vessels that diffuse stuff. The veins return the blood to the heart and have valces so that muscles can slowly push it back up.
The heart recieves blood from the venae cavae and into the right atrium. It is divided into the upper chambers, atria, and lower muscle chambers, ventricles. The blood leaves the heart by the aorta and the left ventricle. The surge of blood as the ventricle compresses is called a pulse. The same medulla oblangata controls heart rate. Blood pressure is the pressure of the vessels that is exerted on the body. The pulmonary vessels are reversed in terms of oxygen content. The artery is blue and the vein is red. These link from the output of the right ventricle to the left atrium.
Nitrogen wastes must be cleared out. Amino acids produce amonia, urea, and uric acid. You need water to get rid of wastes while retaining water. Protazoa diffuse out amonia. The hydra also diffuse amonia out. The earthworm have excreatory organs. Humans have the kidney. The renal artery supplies blood to the kidney. After cleaning, the renal vein takes the blood away.
The kidneys remove liquid wastes from the body. The wastes go down the ureter tube and are stored in the unrinary bladder. The urine is excreted using the urethra.Every filtering unit of the kidney is a nepheron. They use force filtration. Tons of water and molecules are forced out out the capillary in the Bowman's capsule. This waste liquid is called the filtrate. You have to recover water and useful materials. This does active transport, diffusion, and passive transport at this stage.
The system regulates salt while expelling nitrogenous wastes and amonia. The hypothalamus uses antidiuretic hormone (ADH) to stimulate the reabsorbtion of water in the blood.
An infection disease is one that puts pathogens or disease producing agents in your body. These factors are usually species specific. Examples are viruses such as a cold virus and bacteria. Some microbes are good for you.
Dieseases are caused genetically, stem from aging, or result from pathogens. Hemophilia and osteoporosis are caused by genes and aging respectively.
The first pathogen formally identified was the bacteria that causes veterianary anthrax. The man, Koch, made Koch's postulates for identifying pathogens.
There are exceptions like STDs, viruses, and leprosy (bacteria) where the stuff won't grow in a pure culture.
There must be hosts for the disease. Some people are carriers and carry the pathogen without symptoms. A carrier is infected, period, and is a resevoir for diesease. It doesn't matter if it shows symptoms of infection. This also occurs during the incubation period. Interspecies transmissions are also possible. Transmission mediums include:
Colds, the flu and STDs are spread by contact. Food poisoning is transmitted by other objects like Saga food. Flies can be vectors of disease and so can rats. Thes study of the spread is epidemiology.
Viruses commonly destroy the cell. Bacteria produces toxins which mess you up in various ways.
The Centers for Disease Control (CDC) in the USA tracks diseases. Diseases that are constantly present are endemic diseases. When people in an area suddenly get the same disease, it is a epidemic.
Any substance that kills or stops the growth of microorganisms when given in small amounts is an antibiotic. These work against bacteria. The consistent use of these compounds have made diseases that are resistant to antibiotics.
Name some diseases that require more than one host (species). What are good precautions against any of the transmission methods. Speculate on what diseases evolved from.
The immune system's primary goal is to provide the body with defenses against pathogens. The lymph system, the entegumentary system, as well as the immune system all play a role in the battle against disease. Humans also harness the power of their nervous system's intelligence to formulate artificial defenses.
Stuff dissolved in the water around tissue is called tissue fluid. It collects in the open ended lymph capillaries and is now called lymph. Before it is returned to blood, it passes through organs. It has three functions:
The filtering is done by a lymph node. These contain lymphocytes which are white blood cells that destroy microbes. The system also includes the thymus gland, spleen, and tonsils.
Skin defends against undetermined microbes. The sking has tightly packed cells and has friendly microbes on it. Mucus and secretions mess up germs too with the enzyme lysozyme which breaks down cell walls.
Other cells that gobble microbes are phagocytes. One type is a macrophage that gathers junk and digests it. Eventually it dies and pus is formed.
Inflamations, the readness, swelling, pain, and heat, from any injury, releases body fluids. The phagocytes come and treat the area. It also creates a fever.
A protein called a complement attaches itself to microbes damaging them and attracting phagocytes.
The blood is able to identify all types of foreign matter. It responds by producing proteins called antibodies that help the rest of the immune system. This was first dicovered by a guy named Jenner and the small pox and cow pox connection. Salk and Jonas also discover the polio vaccine.
Immunity to a specific disease is made when antibodies are formed. First a lymphocyte engulfs the thing and changes its membrane to a self and infection design. Then the helper T cell takes the foreign stuff and gives it to the B cells. The B cells divide and form memory B cells and plasma cells which secrete antibodies. Antibodies are y-shaped proteins that have receptors on the branches of the Y for the antigen. The B cells can also read the macrophage.
Cellular immunity is when the helper T cell triggers a killer T cell or suppressor T cell. The T cell divides to a memory T cell and killer cells which seek out infected cells and destroys them.
All the above is a primary response. When the antigen comes a second time, it triggers the memory T cells and memory B cells to divide and kill the junk. You never feel sick cause this s quick.
Immunity is developed by vaccines or via the mother. This is the passive version while the active version is where you get the disease. A vaccine is where the dead or weakened version of stuff is injected in you.
Kaposi's sarcoma, a skin disease attacked people as their immune systems got weaker (1981). In 1983 the pathgen dubbed HIV for human immunodeficiency virus was found to cause AIDS, acquired immune deficiency syndrome. It is spread through exchange of ody fluids. The incubation period is as loong as eleven years at which time the patient exhibits ARC AIDS related complex.
This is the overreaction of the immune system. The primary response's antibodies stick to the cells. In the secondary response, the antigen sticks to the antibodies on the cells. The cells now leak all chemicals including histamines. This causes allergic symptoms which is called anaphylaxis if it is really serious. New chemicals are messing us up.
Autoimmune disease change molecules in your body and makes them look foriegn to your immune system. Multiple Sclerosis is an autoimmune disease. Steven Hawkings has this. Transplant are messed cause the body considers it foreign. If it doesn't work, it's called rejection. These cases, the antibodies are messing you up.
How can the immune system be aided. What sort of thing could act as a supplement or replacement of the immune system. How could the immune system be improved.
Digestions is the process by which foods are decomposed so that the organism may use them. This system can be described by the number of openings it has and by where the digestion occurs. The presence of both a mouth and an anal sphincter designates a complete digestive tract while one that does not have two openings is called imcomplete. Evolution creates specialized chambers along the tract to adapt to digestive stuff. The digestion can take place outside the cell, extracellular, and inside the cell, intracellular.
The protazoa phagocytosizes food and digests it inside a food vacuole with lysosomic enzymes. This is intracellular and sometimes has a specific openings.
The hydra has one mouth and digests by secreting juices from an inner lining. The juices break the food down so that the layers of cells can phagocytosize. They use extracellular and intracellular digestion in an incomplete digestive tract.
The flatworm has a pharnx, a tube, that sticks out. This collects food. It is taken into a branched digestion cavity and throughly digests the food and obviates the need for much intracellular digestion. The pharnx also spits out wastes.
This creature has a complete digestive tract. It has many chambers including the crop for storage and the gizzard for grinding with tiny pebbles.
They have a spiral shaped chamber which looks like a screw. This increases the surface area so they can get more food from their food.
What are the basic improvements to a digestive system. What type of digestive system would you put in an omnivore, herbivore, carnivore.
It starts from ingestion, digestion and movement, transfer to cells, excreation.
This is the first place where digestion starts. Mechanical digestion as well as chemical digestion via the enzyme amylase which breaks down starch occurs here. The food enters the esophagus which sends the food the stomach via peristalsis which is the involentary contraction of muscles. The epiglottis prevents flow of food into the lungs.
The stomach is a muscled pouch that further turns the food. It uses gastric juices of hydrochloric acid and pepsin which digest proteins. It holds food until its ready to leave. This junk us called chyme. Ulcers are caused by bacteria.
The first 25 cm of the 6m long 2.5cm wide tube of the small intestine is called the duodenum. This links with the pancreas to get more digestive juices. The pancreas produces enzymes to digest proteins, carbohydrates, and fats. The liver produces many things as a gland, but for the digestive system, it produces bile which breaks down fats and is stored in the gall bladder. The villus in the small intestine are projections that stick out and get food partcles. These villi increase surface area and have microvilli for more.
This collects the indigestable material. It squeezes water out and has bacteria to create gas and vitamins.
How would you attempt to treat a person who lacked pepsin enzyme. What part of the digestive tract is vestigial.
This section was skipped.
The control of digestion is linked to the senses and triggers gastric juices. The stomach then intestines control the flow of digestive juices as the food moves along.
Glucose levels ar maintained by food intake and homones. The body stores energy in glycogen. An exocrine gland is one that has a duct to release chemicals. An endocrine gland is one that has no duct and releases homones to the blood. These homones are meant to send a message to a target tissue.
Hormones involed in glucose levels are glucagen which makes the alpha cells send out glycogen. Insulin does the opposite and makes them absorbe glycogen. This is produced in the pancreas.
The thyroid gland is the one that watches over energy use and growth. It makes calcitonin which regulates calcium and phosphates. The parathyroid glands secreate parathyroid hormone (PTH) which encourages calcium, phosphate, and magnesium absorbtion in the intestines. It encourages the kidneys to reabsorb calcium and magnesium. PTH also increases the production of vitamin D.
Nutrients can be catagorized into six catagories:
These catagories are grouped into micronutrients and macronutrients. Micronutrients are minerals and vitamins which are consumed in milligram quantities. Carbohydrates (CH2O), fats, and proteins are macronutrients. See Experiment Dated Febrary 9, 1996.
The body prefers carbohydrates in foods like cereal and fruits. Digestion breaks carbohydrates down except for fiber or cellulose which helps stimulate the digestive tract (peristalsis). These are the sugars which are a good source of energy. Fat is good building and energy material that comes from meat, nuts, and dairy products. Hormones and insulation come from fat. Saturated fat and cholesterol come from animal products. These serve as energy storage, insulation, and padding. Proteins are used a energy only if the body needs energy. Eight amino acids cannot be produced by the body and need to be consumed. The average intake should be at least 1 gram per a kilogram day.
Minerals, inorganic substances that serve as building materials or chemical reactants, are needed by humans. These are normally ingested with macronutrients. Sodium and pottasium are inportant for nerve function. Calcium is important for bones. Phosphorus is important for ATP. A vitamin regulates processes in the body. There are fat and water soluble vitamins. The water based ones you can unrinate out while the others are stored in your liver. Vitamin C is important for collogen protein which is used in cartilege. You can get vitamin D from you skin and some B and K vitamins from intestial bateria. Water is absolutely needed in the body. See page 966 for the functions of vitamins. Vitamin A is fat soluble and helps the growth of epithelial cells including skin.
The special nutrient water comprised a majority of the body weight. You should take at least two quarts a day. If you are thirsty, it is too late to recharge.
Some non sequitur terms include: herbivore, plant eater; carnivore, meat eater; omnivore, eater of all; saprophyte, external stomach eater i.e. mushrooms.
Chemical reactions break down and synthesize other chemicals. The energy for some reactions is measured in Calories. These are actually kilocalories. A calorie is the energy required to raise one gram of water one degree celsuis. Carbohydrates and proteins "weigh" 4 C/g while fats are 9 C/g.
The optimum diet is where you balence intake and consumption of calories so there is no waste.
This system is run by hormones which are secreated from a gland and affects target organ. The endocrine gland in humans has no duct to eject the hormone. The cells put it directly into the blood stream. It travels over body fluids and is relatively slow but long lasting.
Plants use hormones, the Auxin class, to govern growth. Phototropism makes it grow toward light while geotropism makes it grow toward the earth. Thylene hormone inhibits fruit ripening, and some other hormone, which decays in the cold winter, prevents plants from budding in the fall. Insects use the juvenvile hormone to determine when to metamorphisize.
In humans, this system runs in parallel to the nervous system in controlling the body. It is slower but more permanent that the nervous signals. The hormonal system is regulated by the hypothalamus and the pituitary glands. The hormones that come from these glands are called trophic hormones which control other glands.
An example of a hormone "system" is the thryroid regulation. First the hypothalamus, recieving a cold signal, emits TRH (Thyroid Releasing Hormone). This hormone triggers the pituitary's release of TSH (Thyroid Stimulating Hormone). Finally, the thyroid gland produces thyroxin which warms the body and shuts of the hypothalamus TRH production. The final step of shutting off the hormone is called negative feedback.
Other hormones that are semi-important are prolactin and human growth hormone (HGH). Prolactin triggers milk production while HGH affects growth, especially of bones. The latter can make dwarfism which can be combatted by collecting HGH from engineered bacteria, pigs, and cows. Important glands include the thymus gland, pancreas, and adrenal glands. The thymus gland is located above the heart and controls immune system development. The pancreas produces insulin which allows blood glucose to enter and be used by the cells. The lack of insulin is called diabetes and can be treated with genetically engineered bacteria-produced insulin. The adrenal glands are located above the kidneys and produce adenaline and stress hormones. Adrenaline preps us for "fight or flight." The stress hormone is a lower key adrenaline and increases blood sugar, constricts blood vessels and raises blood pressure. This causes more stress and damages our organs.
Neurons are single cells in the nervous system. They are composed of dentrites, cell body, and axon. Dentrites receive impulses and transmits them through the cell body and to the axon. It transmits one way. Neuron endings, the dentrites and axons, branch extensively. There are about 1000-10000 connections to the dentrites in the 2x1012 neurons in the body. Each pathway is a memory, and there are more of these than atoms in the universe.
When a neuron controls a muscle it is a motor neuron, when it senses stuff, it is a sensory neuron, otherwise its an interneuron. The signal first starts from a receptor which translates stimulus to nerve signals. Humans have many kinds of receptors. Then it goes to a sensory, inter, motor neuron, and finally the effector organ. The interneurons decide, interpret, and integrate sensor information. It allows many reactions to the same stimulus. The reaction time is the time required to respond to a stimulus.
The neuron transmits pulses to the brain and stuff. The membrane at rest lets potasium in but not sodium. Both are positive ions. The sodium-potassium pump does the rest. The sodium is on the outside while the potassium is balenced. The impulse messes with the membrane and the sodium is let in causing a charge imbalence. This only occurs starting at a dentrite if and only if a certain threshold is reached. The neuron can only be stimulated so often
Axons outside the brane and spinal cord are often covered with a myelin sheath composed of Schwann cells. This is the insulation for the wire. The gaps in between the cells allow the depolarization to jump from place to place, increasing speed. The protected axons form white matter.
Between neurons is a synapse. The impulse also allows calcium ions to enter the axon ending. This causes neurotransmitter vesicles to exocytosize. The neurotransmitters attach to the dendrite and continue the signal. There are around 24 neurotransmitters.
The brain and the spinal column make up the central nervous system (CNS). The other nervous system is the peripheral nervous system (PNS).
The brain is divided into the cerebrum, medulla oblongata, and cerebellum. The cerebrum is divided into thwo hemisheres and is gray and wrinkled. The cerebellum is in charge of balence, posture, and coordination. The medulla oblangata controls involentary activities. The midbrain has the pons and the midbrain which communicates with the other parts of the brain.
The somatic nervous system allows volentary control. A reflex is an involentary response to stimulus. The autonomic nervous system, under the supervision of the CNS carries out functions. There is both the parasympathetic and sympathetic nervous sytem. The sympathetic nervous system controls us in times of stress. The parasympathetic nervous system controls us at rest.
These are done by receptors which translate stimulus into nerve signals. There are external receptors as well as visceral receptors which detect interal stuff like CO2 and oxygen levels. The proprioceptors gives feedback on muscle positions as well as their speed and strength. These all go to brain centers where the pain is actually felt. The hypothalamus is responsible for pain, pleasure and thirst.
Taste and smell are linked. Taste is felt by the taste buds on the tongue which can experience sour, salty, bitter, and sweet. They respond to a specific shaped molecule. There are interal ones that detect oxygen. The nose is said to have seven different receptors and a infiate levels of the seven chemicals.
It is a camera type eye. It uses one lens to focus the image like an octopus eye. The sclera is the outermost white though connective tissue that protects it. The cornea is the clear part of this. Now they can shape the cornea to get rid of contacts and glasses. The iris is the circular muscle that regulates the amount of light that goes into the eye. The pupil is the hole in the iris where the light can pass. The lens is made of layers of proteins that let it flex. The choroid is the dark brown layer that blockes stray light and supplies blood. The ciliary body is in front of the choroid and changes the lens' shape and has muscles on it. The retina with its rods and cones detects light, dark, and colors. The rods cannot function in bright light and are not fine enough to see shapes, but they can detect movement. The cones use an RGB color scheme. The optic nerve gathers all of these into a bundle.
These include hearing, balence, and touch. The ear concentrates vibrations in the cochlea, a fluid filled snail shaped organ. Sound starts as air waves which vibrates the ear drum then the hammer, anvil, stirrup then the fluid in the cochlea. The fluid jiggles little hairs which send nerve impulses to the brain down the auditory nerve. The balence sense comes from the semicircular canals which are also filled with fluid. These respond to three axis of motion and respond only to acceleration. There is also a vestibule that dectects head tilt. The sense of touch comes from the skin neurons which detect hot, cold, touch, pressure, and pain. These are concentrated on the fingertips, eyelids, lips, tongue, and palm.
Drugs, any substance that reacts with the body's functions, affect the endocrine and nervous systems by duplication receptor site patterns.
Some drugs helps prevent, cures, or relieves a medical condition. Pain is often relieved by narcotics which dampen the nervous system. Cardiovascular problems often can be treated with drugs. For nervous disorders, stimulants which increase nervous system activity are used. Depressants, which cause drowsiness, can relieve some anxiety. Relatively untested drugs should be tested for immune reations.
The development of drugs requires many things. First the early stages identify the disease area, prospective molecules, time frame, and route of administration like IV or oral. They need money and need to be able to market the drug. There are two types, the Me-too copy cat drugs and the new drugs. The Me-toos are easier (5 yrs) and less expensive (less documents and tests) and have a market already made. Otherwise eight to ten years and 360 million dollars are required as well as 17 car loads of paper work for approval. The testing starts in the test tube with 10,000 different chemicals then goes to live animals (500) and then humans (10) and finally is approved (1). They need to do toxocology, patents, investigative new drug (IND), tolerance, safety, absorbtion, elimination, dosage, response, efficacy, and chronic animal toxology tests.
The human trials use a double blind where the patient nor the doctor knows whether the drug is a drug or a placebo. The central administrator uses codes to analyse the samples. This requires statisitics. Another important point is side effects. These are negative effects that come along with getting the real treatment or cure.
Any use other than the intended use is a misuse of a drug. It can lead to addiction, both physilogical and psychological, just as medicinal drugs can. The body can become tolerant of the drug and requires more of it to reach the desired effect. When the addicted body stops recieving the drug, it goes into withdrawal where the body is ill.
There are stimulants, depressants, narcotics, and hallucinogens. One example of a stimulant is cocaine. It produces a euphoric high and fools with the sympathetic nervous system causing high blood pressure. The same is ture for amphetamine, an illegal stimulant. Caffine and nicotine are also drugs as they exhibit the same drug symptoms.
Alcohol is a depressant which is easily produced. It blocks the motion of ions in the nerve cells. Barbiturates are also depressants.
Opiates or narcotics act on the brain. Heroin is a popular version of this. Withdrawan is painful and tolerence develops quickly.
Hallucinogens changes moods, stimulates the CNS, and thoughts. There are both natural and synthetic stuff.
Reproduction is the continuation of a species through copies of the parent called offspring. Old guys thought that sperm were little tiny humans. Instead, they are DNA strand holding messengers. DNA does not change that much between species. The stuff that is identical, but serves different purposes are called homeobox genes. Reproduction can be broadly catagorized into asexual and sexual reproduction.
Asexual reproduction includes binary fission which occurs only in unicelluar life, vegetative propagation which a new organism grows from a part of the old, budding where a tiny baby buds on the parent, and parthenogenesis which females can have a baby female without sex.
Sexual reproduction involves two parents. All organisms have this type of reproduction so that the DNA can change. The DNA parts are not necessarily equal. The mating process is different. Some species rely on other species to carry the sperm, while others, hermaphrodites, have both sex organs and mutually exchange DNA.
Term Definition Homologous Chromosomes paired chromosomes with genes for the same traits arranged in the same order Centriole cylindrical structures composed of microtubules that duplicate during interphase and move to opposite ends of the cell during prophase; found in animal cells but seldom in plant cells Centromere cell structure that joins two sister chromatids of a chromosome Cytokinesis the process where the cytoplasm splits
Table 1: Terms
The cells cycle is the sequence of events that result from growth and division of a cell. The growth occurs in the interphase which also replicates the DNA at a specific time. They carry out normal metabolic stuff. The first substage marks cytoplasmic growth. The second subphase initiates DNA replication while the third subphase does final preparations. This is so that the chromosome number is equal in both child cells. This process is called mitosis. In humans, the blood cells are the fastest at this process.
Mitosis starts in prophase. This phase is the longest and changes chromatids into chromosomes. The two chromotids that were duplicated are called sister chromatids. They are held in an x shaped structure with a centromere in the middle. The centrioles emit spindle fibers which are also present in plants. The spindle is shaped like a cage of microtubules. In metaphase, the chromosomes attach to the spindle fibers on the centromeres. The sister chromatids face their respective poles. During anaphase, the separation of the sister chromatids occurs. It is unknown how this happens. The telophase marks the final separation. Prophase measures are reversed. The nuclear memebrane appears while the spindle fibers disappear. The plasma membrane begins to cut off the two new cells. The chromatids uncoil. The plant cells form a cell plate instead of moving the plasma membrane in. The mitosis process guarantees an identical cell which does the same as the parent.
The cell divisions of both mitosis and meiosis types require chromosomal duplication. While meeosis requires two divisions to get the haploid number, mitosis maintains staight duplication with one division. Meiosis is an important step in reducing the chromosomal number for sexual reproduction. Meiosis homologous chromosomes separate in the first division. One can diagram chromosomes to observe this using a karyotype. The meiosis cycle can create 2n different chromsomal combinations without the additional randomness of crossing over. The sexual reproductions variations help organisms adapt to the enviroment.
Each cell has two of each kind of chromosomes. This cell is called diploid. The gametes only contain one of each kind of chromosome and is therefore called haploid. This transmits certain traits of the species. The paired homologous chromosomes are arranged in the same order and control the same trait. Meiosis is used to create haploid cells that combine to form a new organism. This is so that one would not have a quadploid cell from mitosis combination. Meiosis produces gametes in specialized body cells. These include sperm and eggs which combine to form a zygote. In humans the eggs do not split equally but leave polar bodies. The combination of the haploids is a part of sexual reproduction.
Interphase is the same. Prophase I is like the normal one. It forms a tetrade which the homologous chromosomes are opposite their duplicats and their partners. They can get tangled and cross over material. The metaphase I lines up the chromosomes in the middle. In anaphase I the chromosomes separate. The centromere does not split and the homologous chromosomes move to different ends. This makes sure that only one chromosome of the pair goes to each cell. Telophase I reverses the prophase I stuff. The chromosomes are still doubled and another division is required. Meiosis II have a short interphase and do the same thing this time spliting the centromere. This results in haploid cells which turn into gametes.
Mitosis creates identical cells. Meiosis allows for changing of characteristics. It offers exponential diversity as chromosome numbers increase. Crossing over also increases uniqueness. This randomness is called genetic recombination.
Humans can be identified by their primary sex characteristics at birth. Later after adolenscence, do they become fully mature. The genders repectively begin spermatogenesis and oogenesis. These processes are hormone controlled by the hypothalamus's LRH, FRH, the pituitary's LH, and FSH. It is unknown why puberty tends to start from the ages of 10 to 13 years old. The hormones target different organs in the sexes.
They need to produce sperm. They are made in the testes that are held in the scrotum. It maintains 3 Celsius degrees lower that the normal body temperature. It takes 74 days for a sperm to mature. One male can produce 300 million sperm a day. The departure of the sperm leaves the epididymis, a coiled tube, and the vas deferens which takes it away. The sperm needs fluids to travel in. The seminal vesicles, protestate gland, and bulbourthral glands add junk and form semen.
The start of mature sexuality occurs after puberty. The hypothalamus makes FRH and GRH. The pituitary starts making FSH (follicle stimulating hormone) and LH (luteinizing hormone). The LH causes testosterone production in the insterstitial cells in the testes. The FSH targets the seminiferous tubules to make sperm. Secondary stuff includes hair, muscles, bones, growth, vocal changes, and slightly more aggressive behavior. The hypothalamus is the starting point and keeps the negative feedback system working.
The female has two ovaries which are near tube openings of the oviduct. The cilia in the oviduct and muscular contractions move the egg down the tube. This leads to the uterus which has an opening in the lower end called the cervix which leads to the vagina which is the exit to the world.
Like males, they get a signal from somewhere to start FSH and LH production. The FSH stimulate a follicle which is the epithelial cells which surround an egg. It also triggers estrogen which causes female secondary sex characteristics. They get fat in the breasts, buttocks, thighs, get hair, bigger hips, menstrual cycle, and maintenance of the sex organs.
Eggs a first developed during prenatal growth. It is celled in prophase I. Every month, one or a couple of follicles are completed and are sent out in ovulation.
After ovulation, the follicle becomes the corpus luteum wihch secreates progesterone, a steroid. It targets the uteran lining. The process of preparing for ovulation is called the menstrual cycle. The cycle is usually 28 days. If the egg is not fertilized, the uteran lining is shed. The cycle is divided into the flow, follicular, and luteral phases.
The flow phase emits blood, tissue fluid, mucus, and epithelial cells to exterior. FSH rises and the follicle develops.
The next phase, follicular, lasts from day six to day fourteen and more estrogen is produced from the primary follicle. This kills off the other follicles The estrogen shuts off FSH. The uteran lining grows. Estrogen causes LH levels to rise making the follicle rupture. Body temperature rises as well as cervical mucus.
The last phase, luteal, makes the corpus luteum which is encouraged by the LH. It produces estrogen and progesterone. It also shuts off LH. It speeds up lining development. If the egg doesn't make it, the shut off of LH and FSH cause the corpus lutuem to degenerate and the lining is shed. In lower mammals, this lining is reabsorbed. If there is a pregnancy, the placenta makes CG which acts like LH, keeping the corpus luteum alive. Their more complex hormonal cycle is keyed so that the lack of testosterone enables it.
After the egg is released, it has 24 hours to live. Sperm can live 48 hours. During the three day time span that fertilization can occur, only one sperm can make it. The electrical charge changes so that other sperm can't enter with their enzymes and DNA. The new zygote gets nutrients from the fluids in the oviducts. It first makes a morula then a blastocyst. After about a week, it lands in the uteran lining. This is called implantation.
The amniotic fluid and sac cushion the fetus and also it helps regulate temperature. The umbilical cord attaches the fetus to the placenta to the uterus. The outer membrane of the amniotic sac forms a chorion and later the placenta. The chorion villi use diffusion to transport materials rather than mixing blood. The chorion secreates gonadotropin (CG) which keeps the corpus luteum secreting progesterone to keep the uteran lining in place.
The development of nine months or 270 days is divided into three trimesters. The first trimester forms all body systems. This embryo turns into a fetus at the end of this period and is 28 g and 7.5 cm long. The primary developement is in organ formation and is highly sensitive to chemicals. The second trimester has massive growth then slowing down. This is the point of viability outside the mother. It does not have lungs and cannot regulate temperature. It has definate primary sex characteristics. The primary development is in organ formation and growth.The third trimester the fetus triples in mass. It can move and kick. The eyes open in the eight month. It is 3300 g and 51 cm long. It turns head down. The primary development is in growth and the mother transfers a supply of antibodies to the child.
The hormons relaxin and ocytocin dialate the cervix and cause the uteran wall to contract respectively. The uterus contracts in a rythmic en accelerondo. The after birth is particularly significant in that the bleeding from it, if not stopped, is fatal to the mother.
It is possible to detect more malformities thanks to technology. Genetic counseling is where they work to find whether the couple is prone to genetic disorders. They use family histories as well as blood analysis. Using prenatal testing, one can see if the baby has one or more of a hundred testable genetic disorders. They use a procedure called amnicentesis where the amniotic fluid is cultured and genetic tests are run.
The oxytocin hormone from the pituitary triggers labor, the process of birth. There are three stages, dialation, expulsion, and placental. The initial stage mildly contracts the uterus and the cervix dialates. This is the longest stage. The next expulsion stage pushes the baby out with powerful uteran contractions. This stage can last up to one hour. The placental stage occurs within 15 minutes of birth and sends out the placenta. The muscles continue to contract to close the uteran blood vessels. The baby's cord is clamped and cut. The small part of it dries and falls off leaving the permanent belly button.
Growth is not linear, but it is regulated by the human growth hormone (HGH). It acts on the muscles and skeleton. The child as an infant grows fast and triples weight in a year. By the end of two years, they can talk, walk, crawl, sit, and have quadrupled their birth weight. The infant turned child now increases mental acuity while engaging in a steady growth program. Puberty gives people a growth spurt and continue to grow to their peak. The older people have slower metabolism and stuff starts wearing out. The skin loses elasticity and hair pigment as well as bones slowly lose their stuff. Senses tend to be reduced.
Contraception includes mechanical, chemical, and post facto. Permanent mechanical contraception includess tying tubes, cutting the vas deferens in vasectomies and historectomy or cutting out the uterus. Some of the above can be undone but can cost significant sums. The other mechanical methods include condoms and diaphragm. Chemical contraception includes the pill and norplant. Abortions can occur the day after and include the pill RU-486.
Genetics covers Mendel and laws of genetics and genetics problems dealing with the structure and function of genes. As we have stated before, meiosis is a type of cell division that splits the duploid to a monoploid chromosome number. This splits up the homologous chromosomes that control the same traits.
Genetics is the study of inheritence or how traits are passed from parent to child. This links directly to the mathematical study of probability which governs insurence rates and actuary tables.
Mendel was a monk who lived around 150 years ago. He discovered the laws of genetics through meticulous labs which left him no time to perform other jobs. His work was not understood until later. Darwin did not understand his work either. His experiments were perfect examples of scientific method. He tested one attribute at a time in large sample groups. Then he counted the results. He made sure his sampling was pure and untainted. He also meticulously isolated his sample groups. He did this all without the cell theory and against the common belief that inheritence was related to blood, a liquid.
His famous experiment with peas proceeded as follows. He breed red flower and white flower peas for many generations so that they were pure bred. Then he mated them and they came out all red flowered. Then he mated them again and they came out 3 reds to 1 white flower plants. Mendel thought and though and poof, he came up with the following expliantion which he tested by breeding a pure white with a tainted red from the first generation.
A simple example is the recessive attached earlobe trait. Other traits such as Huntington's disease is carried in a dominant gene. This diesase degrades the mental capacities during the ages of 30 and 50. The converse is cystic fibrosis or CF, a recessive gene. This is where mucus builds up. Treatment is availible. Another recessive attribute is sickle-cell anemia. This is more common among people whose ancestry was around the Mediterrenean. The blood cells in this disorder are shaped like sickles and have shorter life spans. They clog the vessels and reduce RBC counts. The heterozygous population shows some of the symptoms. The Tay-Sachs disease affects the CNS. The cause is that an enzyme that breaks down lipids in the brain is not present and movement as well as sight deteriorates. It kills by the age of 5. Unlike the others, Phenylketonuria or PKU is treatable. The disorder prevents the conversion of phenylalanine, an amino acid. The mother initially provides the enzymes, but once the child begins feeding on its own, it is poisoned by the high levels. This normally caused mental retardation, but now a test can be done and the diet adjusted. This brings a new problem with when she has a child. The phenylalanine levels are too high and affect the fetus regardless of its phenotype.
Multiple Alleles are used in blood types. A human blood type is dictated by two of three potential genes. Each person has two of these genes. The genes are normally labeled IA, IB, and i. In this case, IA=IB and IA>i and IB>i. The blood type A has A type proteins on the membrane and B type antibodies which are generated without prior infection in the blood.
Blood Type Protein on Cell Antibodies Genotype Membrane A A B IAi or IAIA B B A IBi or IBIB AB A and B none IAIB O none A and B ii
Table 2: Blood Types
Sex linked genes are those genes that occur on the female X chromosome and are not challenged by the male Y chromosome. The female has XX and the male has XY. For these problems, use a Y blankness placeholder that determines sex. This placeholder does not influence the phenotype and the phenotype is solely dictated by the one gene. If the placeholder is absent, the offspring is female and should be interpreted using the trait genotype phenotype table.
Run the single trait for each trait separately. Then to combine them, multiply the single trait results.
This works just like the single trait only with more genes to determine dominants.
This works like multiple alleles with a Y placeholder. The only slight difference is the sexes which can influence an answer.
Term Definition GenotypeGenotype The genes that the individual has. PhenotypePhenotyp The physical type that the individual represents as a result e of the genotype. Discontinuous The population manifests a finite number of levels of traitDiscontinuou phenotypes. s trait Continuous The population manifests an infinate number of levels of TraitContinuous phenotypes. Trait
Table 3: Genetic Terms
DNA is a polymer with many nucleotide monomers. A nucleotide has a simple sugar, deoxyribose, a phosphate group and some nitrogen base. A nitrogen base is adenine, guanine, cytosine, or thymine. Two chains form and are twisted and bound by hydrogen bonds forming a double helix. The DNA ordering determines the difference in organisms. When DNAs are similar, scientist think that the organisms are more closely related.
The parents give copies of their DNA to their offspring. With replication, a species can survive. The two strands separate and you can always generate the opposite strand by pairing. An enzyme unzips the double helix while another enzyme bonds the incoming nucleotides.
Watson and Crick first found DNA in 1930. They used x-rays and other stuff to find out about its structure. They noticed that A paired only with T and C paired only with G. The strands split anywhere along the lenght in mutiple places and duplicate.
Hershey and chase exerimented with bacteria. They first used bacteria with heavy nitrogen and the DNA became heavy. They then placed it in light nitrogen, creating half and half DNA. Then they let them go a second generation and the DNA became half half and half and half light.
The DNA gets translated to messenger RNA (mRNA). This goes and makes the protein polymer with specific amino acid order. The dominant gene protein produces more effective proteins than the recessive ones.
After copying DNA to mRNA, in groups of three nucleotides called codons, the mRNA arrive at the ribosome where there are floating amino acide carrying anti-codons with the "other side" of the mRNA. These are physically covered in nucleotides with a special three in the position for attachment.
The DNA is encoded in codons of three. This gives 64 combinations for 20 amino acids and oddball stop and start codes. These codes are universal. The single stranded RNA, using uracil, is subjected to transcription into proteins. Parts of the DNA code are also in the ribosomal RNA (rRNA). Transfer RNA (tRNA) brings the amino acid of the proper type next to the codon and adjacent codon. This stuff was found by using radioactive amino acids.
Sometimes the DNA changes and this is called a mutation. When a single nucleotide changes, it is called a point mutation. This changes only one amino acid or codon. This occurs in sickle cell anemia. When something is inserted or deleted, it is a frameshift mutation. This changes all codons after the fact. Chromosomal mutations are the variety that have too many or too few chromosomes in the offspring. This occur as nondisjunctions when a chromosome fails to separate during meiosis I. When this gamete unites, they will have three homologous chromosomes and have a trisomy. The lack of a chromosome usually means death, but there are human females with a single X chromosome, a monosomy.
People have made hobbies of exploring the world and the backyard birds and plants. Some began to systematically catalog stuff. Ecology studies the interaction between species and the environment. They use the scientific method. Life can only exist in a biosphere with atmosphere, water, and land. There are different parts of the biosphere for different species. These members depend on non-living resources or abiotic factors.
The species depends on others to live. A population is a group of organisms of one speicies living in the same place at the same time that they interbreed. A community is a set of interacting populations. Adding the non-living factors makes an ecosystem. A niche is the role that the organism plays and a habitat is where the organism lives.
Autotrophs are organisms that produce food. The ones that eat the autotrophs are heterotrophs. Heterotrophs are broken down into scavengers, decomposers, and herbivores. Scavengers feed on dead animals. Decomposers break down wastes and decaying matter.
Several relationships are possible between species. There is symbiosis where they live together. There is commensalism where one benefits and the other is not harmed and is not helped. There is mutualism where they actually help each other. There is parasitism where one feeds and hurts the other.
A food chain is where energy is passed down from an autotroph to the decomposers. Each element in the chain is within a trophic level, a feeding step. An organism can exist at many levels. A better way to express the eating habits of this organism in relation to the environment is a food web which interconnects food chains. Each level reduces the amount of energy availible. The excess energy is released as heat.
Several cycles are present in the environment. One of them is the water cycle. It starts as gas then precipatates then the animals dring and is respirated. The carbon cycle starts as CO2 in the atmosphere then it is combined with hydrates to form food in autotrophs. The plants are decayed and form fossil fuel. This is burned making more carbon dioxide which start the cycle again. The nitrogen cycle is taken up from the ground and the air by plants and then enters the heterotrophs. When they die, decomposers return the N to the air. The phosphoris cycle similarly.
The environment changes a lot, but there are limiting factors.The factors can be living or non-living. They limit the population. Tolerence of species is also important. The tolerence is how much fluctuation a species can handle.
A succession is where one community completely takes over another. The new site and the community that forms on barren land is called the primary succession. That community reaces a stable point called a climax community. New habitats form and new species come to live in the place. The seconday succession is where the habitat is not completely destroyed and some community members remain.
A biome is a large group of ecosystems that share the same type ofe climax community. The world is mostly water and there are several zones. The first is the photic zone where the light reaches. The deeper part is called the aphotic zone. An estuary is where the fresh water meets the salt water. An intertidal zone is where the organism lives on the beach or rocky shore. 92