Results for "cell body"

Cell Body and Genetics of Aging

NEUS 609 - Synapse formation

Biology and Medical Terminology: Cell, Body, and Chemistry Roots

Physiology of Cell, Body Fluids & Homeostasis – Lecture Notes

System Interactions in Animals Tools Finish System Interactions in Animals The human body is made of many different organ systems. Each system performs unique functions for the body, but the systems also interact with each other to perform more complex functions. Major Organ Systems Body Systems In humans, cells, tissues, and organs group together to form organ systems. These systems each perform different functions for the human body. The major organ systems and their functions in humans include: The Nervous System — The nervous systems consists of two parts. The central nervous system consists of the brain and spinal cord, while the peripheral nervous system consists of nerves that connect the central nervous system to other parts of the body. The brain plays an important role in interpreting the information picked up by the sensory system. It helps in producing a precise response to the stimuli. It also controls bodily functions such as movements, thoughts, speech, and memory. The brain also controls many processes related to homeostasis in the body. The spinal cord connects to the brain through the brainstem. From the brainstem, the spinal cord extends to all the major nerves in the body. The spinal cord is the origin of spinal nerves that branch out to various body parts. These nerves help in receiving and transmitting signals from various body parts. The spinal cord helps in reflex actions of the body The smallest unit of the nervous system is the nerve cell, or neuron. Neurons communicate with each other and with other cells by producing and releasing electrochemical signals known as nerve impulses. Neurons consist of the cell body, the dendrites, and the axon. The cell body consists of a nucleus and cytoplasm. Dendrites are specialized branch-like structures that help in conducting impulses to and from the various body parts. Axons are long, slender extensions of the neuron. Each neuron possesses just a single axon. Its function is to carry the impulses away from the cell body to other neurons. The Circulatory System — The circulatory (or cardiovascular) system is composed of the heart, arteries, veins, and capillaries. The circulatory system is responsible for transporting blood to and from the lungs so that gas exchange can take place. As the circulatory system pumps blood throughout the body, dissolved nutrients and wastes are also delivered to their destinations. The heart is a muscular organ roughly the size of an adult human's closed fist. It is present behind the breastbone, slightly to the left. It consists of four chambers: right atrium, left atrium, right ventricle, and left ventricle. The heart receives deoxygenated blood from the body and pumps this blood to the lugs, where it is oxygenated. The oxygen-rich blood reenters the heart and is then pumped back through the body. The circulatory system is responsible for transporting blood to and from the lungs so that gas exchange can take place. As the circulatory system pumps blood throughout the body, dissolved nutrients and wastes are also delivered to their destinations. Blood circulation takes place through blood vessels. Blood vessels are tubular structures that form a network within the body and transport blood to each tissue. There are three major types of blood vessels: veins, arteries, and capillaries. Veins carry deoxygenated blood from the body to the heart, except for pulmonary veins, which carry oxygenated blood from the lungs to the heart. Arteries carry oxygenated blood from the heart to different organs, except for the pulmonary artery, which carries deoxygenated blood from the heart to the lungs. The arteries branch out to form capillaries. These capillaries are thin-walled vessels through which nutrients and wastes are exchanged with cells. The Respiratory System — The main structures of the respiratory system are the trachea (windpipe), the lungs, and the diaphragm. When the diaphragm contracts, it creates a vacuum in the lungs that causes them to fill with air. During this inhalation, oxygen diffuses into the circulatory system while carbon dioxide diffuses out into the air that will be exhaled. The trachea branches out into two primary bronchi. Each bronchus is further divided into numerous secondary bronchi. These secondary bronchi further branch into tertiary bronchi. Finally, each tertiary bronchus branches into numerous bronchioles. Each bronchiole terminates into a tiny, sac-like structure known as an alveolus. The walls of each alveolus are thin and contain numerous blood capillaries. The process of gaseous exchange occurs in these alveoli. The diaphragm is a dome-shaped muscle situated at the lower end of the rib cage. It separates the abdominal cavity from the chest cavity. During inhalation, the diaphragm contracts, and the chest cavity enlarges, creating a vacuum that allows air to be drawn in. This causes the alveoli in the lungs to expand with air. During this process, oxygen diffuses into the circulatory system while carbon dioxide diffuses out into the air that will be exhaled. On the other hand, expansion of the diaphragm causes exhalation of air containing carbon dioxide. The Digestive System — The digestive system consists of the mouth, stomach, small intestine, large intestine, and anus. It is responsible for taking in food, digesting it to extract energy and nutrients that cells can use to function, and expelling the remaining waste material. Mechanical and chemical digestion takes place in the mouth and stomach, while absorption of nutrients and water takes place in the intestines. The digestive system begins at the mouth, where food is taken in, and ends at the anus, where waste is expelled. The food taken into the mouth breaks into pieces by the grinding action of the teeth. Carbohydrate digestion starts in the mouth with the breakdown of carbohydrates into simple sugars with the help of salivary enzymes. The chewed food, known as a bolus, enters the stomach through the esophagus. The bolus mixes with acids and enzymes released by the stomach. Protein digestion starts in the stomach as proteins are broken down into peptides. This partially digested food is known as chyme. Chyme enters the small intestine and mixes with bile, a substance secreted by the liver, along with enzymes secreted by the pancreas. The digestion of fats starts in the small intestine as bile and pancreatic enzymes break down fats into fatty acids. The surface of the small intestine consists of hair-like projections known as villi. These villi help in absorbing nutrients from the digested food. The digested food enters the large intestine, or colon, where water and salts are reabsorbed. Any undigested food is expelled out of the body as waste. The Skeletal System — The skeletal system is made up of over 200 bones. It protects the body's internal organs, provides support for the body and gives it shape, and works with the muscular system to move the body. In addition, bones can store calcium and produce red and white blood cells. The Muscular System — The muscular system includes more than 650 tough, elastic pieces of tissue. The primary function of any muscle tissue is movement. This includes the movement of blood through the arteries, the movement of food through the digestive tract, and the movement of arms and legs through space. Skeletal muscles relax and contract to move the bones of the skeletal system. The Excretory System — The excretory system removes excess water, dangerous substances, and wastes from the body. The excretory system also plays an important role in maintaining body equilibrium, or homeostasis. The human excretory system includes the lungs, sweat glands in the skin, and the urinary system (such as the kidneys and the bladder). The body uses oxygen for metabolic processes. Oxygen metabolism results in the production of carbon dioxide, which is a waste matter. The lungs expel carbon dioxide through the mouth and nose. The liver converts toxic metabolic wastes, such as ammonia, into less harmful susbtances. Ammonia is converted to urea, which is then excreted in the urine. The skin also expels urea and small amounts of ammonia through sweat. The skin is embedded with sweat glands. These glands secrete sweat, a solution of water, salt, and wastes. The sweat rises to the skin's surface, where it evaporates. The skin maintains homeostasis by producing sweat in hot environments. Sweat production cools and prevents excessive heating of the body. Each kidney contains about a million tiny structures called nephrons, which filter the blood and collect waste products, such as urea, salts, and excess water that go on to become urine. The Endocrine System — The endocrine system is involved with the control of body processes such as fluid balance, growth, and sexual development. The endocrine system controls these processes through hormones, which are produced by endocrine glands. Some endocrine glands include the pituitary gland, thyroid gland, parathyroid gland, adrenal glands, thymus gland, ovaries in females, and testes in males. The Immune System — The immune system is a network of cells, tissues, and organs that defends the body against foreign invaders. The immune system uses antibodies and specialized cells, such as T-cells, to defend the body from microorganisms that cause disease. The Reproductive System — The reproductive system includes structures, such as the uterus and fallopian tubes in females and the penis and testes in males, that allow humans to produce new offspring. The reproductive system also controls certain hormones in the human body that regulate the development of sexual characteristics and determine when the body is able to reproduce. The Integumentary System — The integumentary system is made up of a person's skin, hair, and nails. The skin acts as a barrier to the outside world by keeping moisture in the body and foreign substances out of the body. Nerves in the skin act as an interface with the outside world, helping to regulate important aspects of homeostasis, such as body temperature. Interacting Organ Systems The organ systems work together to perform complex bodily functions. The functions of regulation, nutrient absorption, defense, and reproduction are only possible because of the interaction of multiple body systems. Regulation All living organisms must maintain homeostasis, a stable internal environment. Organisms maintain homeostasis by monitoring internal conditions and making adjustments to the body systems as necessary. For example, as body temperature increases, skin receptors and receptors in a region of the brain called the hypothalamus sense the change. The change triggers the nervous system to send signals to the integumentary and circulatory systems. These signals cause the skin to sweat and blood vessels close to the surface of the skin to dilate, actions which dispel heat to decrease body temperature. Both the nervous system and the endocrine system are typically involved in the maintenance of homeostasis. The nervous system receives and processes stimuli, and then it sends signals to body structures to coordinate a response. The endocrine system helps regulate the response through the release of hormones, which travel through the circulatory system to their site of action. For example, the endocrine system regulates the level of sugar in the blood by the release of the hormones insulin, which stimulates uptake of glucose by cells, and glucagon, which stimulates the release of glucose by the liver. The nervous and endocrine systems interact with the excretory system in the process of osmoregulation, the homeostatic regulation of water and fluid balance in the body. The excretory system expels excess water, salts, and waste products. The excretion of excessive amounts of water can be harmful to the body because it reduces blood pressure. If the nervous system detects a decrease in blood pressure, it stimulates the endocrine system to release antidiuretic hormone. This hormone decreases the amount of water released by the kidneys to ensure appropriate blood pressure. Appropriate levels of carbon dioxide in the blood are also maintained by homeostatic mechanisms that involve several organ systems. Excess carbon dioxide, a byproduct of cellular respiration, can be harmful to an organism. As blood circulates throughout the body, it picks up carbon dioxide waste from cells and transports it to the lungs, where it is exhaled while fresh oxygen is inhaled. If the concentration of carbon dioxide in the blood increases above a certain threshold, the nervous system directs the lungs to increase their respiration rate to remove the excess carbon dioxide, which ensures that the levels of carbon dioxide in the blood are maintained at appropriate levels. In this way, the circulatory, respiratory, and nervous systems work together to limit the level of carbon dioxide in the blood. Nutrient Absorption To absorb nutrients from food, the nervous, digestive, muscular, excretory, and circulatory systems all interact. The nervous system controls the intake of food and regulates the muscular action of chewing, which mechanically breaks down food. As food travels through the stomach and intestines, the digestive system structures release enzymes to stimulate its chemical breakdown. At the same time, the muscular action, called peristalsis, of the muscles in the wall of the stomach help churn the food and push it through the digestive tract. In the intestines, nutrients from food travel across the surfaces of the villi. The nutrients are then picked up by the blood, and the circulatory system transports the nutrients throughout the cells of the body. The endocrine system releases hormones, such as insulin, that control the rate at which certain body cells use nutrients. Any excess minerals, such as calcium, in the blood are deposited in and stored by the skeletal system. Waste products produced by the use of nutrients, as well as the leftover solid waste from the digestion of food, exit the body through the excretory system. Throughout the process of nutrient absorption, the nervous system controls the muscles involved in digestion, circulation, and excretion. Defense Several body systems interact to defend the body from external threats. The body's first line of defense is the integumentary system, which provide a physical barrier that prevents pathogens from entering the body. The skin of the integumentary system also contains receptors for pain, temperature, and pressure. If an unpleasant stimulus is encountered, these receptors send signals to the central nervous system. In response, the central nervous system sends commands to the muscles to move the body part away from the stimulus. In this way, the integumentary, nervous, and muscular systems interact to prevent damage to the body. In the event of a break in the skin, the nervous, immune, lymphatic, and circulatory systems work together to repair the wound and protect the body from pathogens. When the skin is broken, specialized blood cells called platelets form a clot to stop the bleeding. These platelets also release chemicals that travel through the circulatory system and recruit cells, like immune system cells, to repair the wound. These immune cells, or white blood cells, are transported by the circulatory and lymphatic systems to the site of the wound, where they identify and destroy potentially pathogenic cells to prevent an infection. Some lymphocytes, white blood cells produced by the lymphatic system, also produce antibodies to neutralize specific pathogens. All of the white blood cells involved in the body's response were originally produced in the bone marrow of the skeletal system. If an infection does occur

neuron cell body location

You place a RBC (0.9%) into a 5% sugar solution. Which statement below is false? The RBC is hypotonic to the 5% solution Which is an example of a sensor in a negative homeostatic feedback loop? Chemoreceptor in carotid body For membrane fluidity experiment, the part of the experiment that actually validated that the membrane was fluid was: The labeled antibodies of the human and mouse intermixing An example of primary active transport would be a protein requiring ATP to transport sodium ions across the plasma membrane. True If a red blood cell is put in a solution and it hemolyzes, then the solution is considered to be: Hypotonic If your body temperature goes too high you can denature enzymes in your body. True What does an integrator do in a homeostatic pathway? Measures the signal coming in to a set point and send a signal out to the body Which of the following represents stages of the cell division (mitosis) in the proper sequence? Prophase, metaphase, anaphase, telophase Which is not true for proteins? They are comprised of mostly cellulose What would be a disturbance for blood glucose homeostasis (normal blood glucose set point = 77mg/dL)? A permanent decrease in insulin production from the Islets of Langerhans Dr. Bio measures your total cholesterol and he reports back to you that your level is 300 mg/ 100 ml of plasma. You do what? Eat more oatmeal and flax to increase your HDL level. How do you make an unsaturated fatty acid? Perform a dehydration synthesis reaction on a saturated fatty acid Which is false for antioxidants? They speed up reactions in your body Which molecules do not dissolve in water? Non-polar Which molecule requires a transport protein to get through the plasma membrane (either channel or carrier protein)? Two of the answers are correct Interphase is considered to be part of normal cell division (mitosis). False What is the function of ATP? All of the answers are correct What are the three kinds of lipids? Triglycerides, phospholipids, and steroids When glycerol combines with 3 fatty acids to form a triglyceride (fat), which of the following chemical reactions has occurred? Dehydration Synthesis How can you alter a protein’s shape? More than one answer is correct If a red blood cell is put into a solution and it maintains its shape, then the solution is considered to be: Isotonic Which molecule requires some type of transport protein to get through the plasma membrane? Sodium Ion Cofactors are molecules that activate enzymes. Which is not a cofactor? Mercury The nitrogenous bases found in DNA have complementary paring. Which pair is correct? C-G Which is not true for meiosis? Results in a gamete that is 2N In the diagram below the two solutions are separated by a semi permeable membrane. In which direction will net movement of water occur? From side A to side B Which is not a component of a DNA molecule: Ribose Sugar Phospholipids are similar to fatty acids except for? Phospholipids have a phosphate group Which is not true for cells? They allow diffusion of all molecules If you combine a molecule of glucose and fructose, which statement is true? You have formed sucrose Which is true for enzymes? Activity will increase until the enzyme becomes saturated What method would you use to get glucose into a cell along/down it’s concentration gradient (from high to low)? Facilitated Diffusion Which is not considered an integrator in a negative homeostatic feedback loop? Pancreas Which phase of the cell cycle is where cytokinesis takes place? Telophase What vitamin do we produce by sitting in the sun; it aids in calcium absorption from the small intestine? Vitamin D Why is it important to think about ion dissociation in the body? All the above In what order do you use macromolecules for fuel? Carbohydrates, lipids, proteins Which is false for cholesterol? It can dissolve in water/blood You place a RBC (0.9%) into a 0.5% sugar solution. Which statement below is false? The RBC is hypertonic to the 0.5% solution Which is not a membrane protein function? Protein synthesis Ingesting (eating) excess hydrophilic vitamins, such as vitamin C, results in excess vitamin C being stored in your tissues. False Diffusion is: The movement of molecules from an area of high molecular concentration to an area of low molecular concentration across a selectively-permeable membrane The hormone responsible for glucose uptake/removal from the blood is: Insulin What method would you use to get sodium ions into a cell against sodium’s concentration gradient (from low to high concentration)? Active Transport Which phase of the cell cycle is where the cell is functioning normally or doing its job? Interphase Evidence for mitochondria once being bacteria that our cells engulfed is: It has it’s own DNA Ionic molecules (ie NA+, K+) can diffuse straight through the plasma membrane. True What is the difference between cis and trans fatty acids? Cis fatty acids have hydrogens on the same side of the carbon double bond and trans fatty acids do not Cofactors are molecules that activate enzymes. Where do we get cofactors from? Vitamins found in fruits and vegetables RNA has what nitrogenous base in place of thymine? Uracil Large polar molecules (ie glucose) can diffuse straight through the plasma membrane? False Which lipoprotein is comprised of more protein and less cholesterol so it scavenges for cholesterol in the blood? High density lipoprotein A normal human being has 46 chromosomes (23 pairs/2N/diploid) in each somatic cell (body cell). True The three main compounds digested by the digestive system are? Fats, carbohydrates, and proteins Meiosis is the process in which our sex cells go from 46 chromosomes to 23 single chromosomes. True The effector in any negative feedback loop is usually: An organ/tissue If a red blood cell is put into a solution and it crenates (shrinks), then the solution is considered to be: Hypertonic Which statement is false for glycogen? It is a disaccharide Enzymes aid in digestion by? Lowering the energy required to break food apart Nonpolar molecules (ie CO2) can diffuse straight through the plasma membrane

anatomy #48 Neuron cell body

cell body

Neuron cell body

Central - brain and spinal cord Peripheral - everything else soma - body dendrites - the fingers that extend from the soma or cell body afferent - from the body to the central nervous system (sensory information) Sensory info - coming into the CNS (from the body) Afferent neuron Interneuron - in between CNS and PNS Motor info - coming out of the CNS (to the body) Efferent neuron Neurons: nerve cells Receive information in dendrites Information flows through the axon Eventually reaches an effector Synapse: gap between two neurons Synaptic terminals Glial cells Support the neurons Schwann cells & Oligodendrocytes Myelin sheath On the axon Function: prevents cross-talk and accelerates the speed of action potential Schwann cell - produces myelin sheath in PNS Oligodendrocytes - produces myelin sheath in CNS Like an octopus: many arms wrapping around different / same neurons unlike Schwann cell Node of Ranvier - space in between schwann cells Saltatory conduction Presence of node of Ranvier allows jumping of signals → much faster nerve impulse jumps from node to node Grey matter - cell body, dendrites, synapses White matter - myelinated axons (white color comes from lipid) Dorsal root ganglion Large collection of afferent neurons near the spinal cord Cell body Location is different in Sensory vs. peripheral neurons Sensory neurons - cell body in dorsal root ganglion Peripheral neurons - cell body in gray matter (make sure to know how to identify which microscope took what kind of pictures) SEM vs. TEM SEM - outer surface TEM - inner matter, more detail? Interneurons Help with more complicated types of signals such as reflex Non-decremental action potential: does not die out over space Energy at first same as energy at the end Nerve impulse Resting membrane potential: Inside of axon is -70 mV due to negatively charged proteins inside Inside: potassium outside: sodium Ions cannot diffuse in and out of membrane: requires proteins to allow exchange Depolarization (sodium influx) Threshold hit: open voltage gated sodium channel → facilitated diffusion of sodium ions (NA+) into the cells → inner charge becomes more positive Repolarization (potassium efflux) Voltage gated potassium channels open a little later → facilitated diffusion of potassium ions (K+) to out of the cells → inner charge becomes more negative hillock Refractory period Absolute: absolutely will not get an action potential during this period Relative: membrane potential lower than -70mV → can get an action potential depending on the size of the stimulus because it requires a bigger stimulus to reach the threshold Sodium-potassium pump Active transport (against concentration gradient) resets the sodium and potassium to allow the nerve impulse to happen again pumps 3 sodium out, pumps 2 potassium in Intensity is indicated by the frequency of action potentials Ex. very hot - thousands of action potentials Ex. nice and warm - some action potentials

Neuron Cell Body and Processes

A&P LAB cell body

Cell Body Locations of Cranial Nerve Fibers

fdjksl afdjs klejfsieofwjnervous system the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems three critical features of the nervous system They receive input from the surrounding world. They process the info from the surroundings. They initiate responses to the internal and external environments, when necessary. neuron a nerve cell; the basic building block of the nervous system dendrites Branchlike parts of a neuron that are specialized to receive information. cell body Largest part of a typical neuron; contains the nucleus and much of the cytoplasm axon the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands glial cell cells in the nervous system that support, nourish, and protect neurons nerves bundled axons that form neural "cables" connecting the central nervous system with muscles, glands, and sense organs how many neurons die everyday? 9,000 When neurons die can they be replaced? no what can kill neurons? alcohol intake, inhaling gas fumes neurons are what kind of cell eukaryotic what does the cell body contain nucleus, mitochondria, endoplasmic reticulum, and so on What does a dendrite do? receives information what does the axon do? carries impulses away from the cell body what does the cell body do? process information sciatic nerve nerve extending from the base of the spine down the thigh, lower leg, and foot How many more glial cells are there than neurons? 9x Do glial cells divide? yes glial cells act as a barrier for harmful things entering the brain blood brain barrier Blood vessels (capillaries) that selectively let certain substances enter the brain tissue and keep other substances out how is the blood brain barrier broken down hypertension, radiation, some infectious organisms sensory neurons neurons that carry incoming information from the sensory receptors to the brain and spinal cord. stimulations like temp, touch, taste, smell, light or sound motor neurons neurons that carry outgoing information from the brain and spinal cord to the muscles and glands Interneurons neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs. peripheral nervous system network of sensory cells modified to receive info from the environment and motor pathways that transmit signals to effectors, the muscles and glands capable of responding to that stimulus sensory pathway nerves coming from the sensory organs to the CNS consisting of afferent neurons motor pathways In the peripheral nervous system, common routes by which motor nerve impulses are transmitted. somatic nervous system the division of the peripheral nervous system that controls the body's skeletal muscles (voluntary) autonomic nervous system the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms. (involuntary) sensory neurons alert the brain of a stimulus motor neurons help the brain to execute a response reflex signal that skips the brain, and goes to stimulate the motor neuron. direct sensory response autonomic nervous system helps us with homeostasis sympathetic nervous system the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations parasympathetic nervous system the division of the autonomic nervous system that calms the body, conserving its energy dendrites recieve signals from external stimuli two ways dendrites receive stimuli through motor neurons and interneurons connecting with other neurons or directly from external stimulus resting potential of neuron its stable, negative charge when the cell is inactive action potential of neuron a very brief shift in a neuron's electrical charge that travels along an axon resting potential is produced as proteins within the neurons plasma membrane pump sodium ions out of the cell and potassium ions into the cell what ion goes into the cell potassium what ion goes out of the cell sodium how does the pumping of ions affect the charge of the cell? more positive on the outside more negative on the inside greater positive charge out of the cell makes the cell polarized when stimulated dendrites briefly open ion channels made of proteins which allow charged ions down the concentration gradient concentration gradient A difference in the concentration of a substance across a distance. when ion channels open the negative charge inside the cell is temporarily changed either decreasing or increasing changes in the cells electrical charge converge from the dendrites to the cell body when charges converge that is called action potential terminal buttons Small knobs at the end of axons that secrete chemicals called neurotransmitters axon terminals (terminal buttons) doe what i response to action potential release contents of vesicles, small sacks of chemicals inside the axon terminal into the space between cells which can influence nearby cells myelin sheath A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next. as the action potential moves down the axon ion channels allow positively charged ions to rush in changing the charge to positive. other ion channels allow positively charged ions to rush out what restores the action potential ion channels letting the influx of positively charged ions to rush put Where are ion channels concentrated in the gaps in the myelin sheath fatty myelin is what color white fatty myelin shows up as white when tightly packed together regions of the brain with many cell bodies and dendrites appear what color gray multiple sclerosis myelin sheath destruction. disruptions in nerve impulse conduction little myelin causes the neurons to lose its ability to conduct electrical impulses which makes it harder for the brain to send signals to muscles synapse the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron at a synapse and neurons interacts with another cell What happens at a synapse? When a nerve impulse reaches the synapse at the end of a neuron, it cannot pass directly to the next one. Instead, it triggers the neuron to release a chemical neurotransmitter. The neurotransmitter drifts across the gap between the two neurons. sacs called vesicles release neurotransmitters into the synaptic cleft synaptic cleft The narrow gap that separates the presynaptic neuron from the postsynaptic cell. what happens when the action al potential reaches the axon terminal? little sacks called vesicles merge with axon cell membrane axon cell membrane presynaptic membrane the vesicles open and release chemicals called neurotransmitters neurotransmitters send a signal to the cell receiving the signal after sending a signal to a cell the neurotransmitters diffuse away and binds to nearby receptor sites after neurotransmitters diffuse the gates open in the post synaptic cell membrane and the signal enters the post synaptic cell after the signal enters a new neurotransmitter is released from the post synaptic cell receptors and is recycled or broken down what are neurotransmitters broken down by enzymes found in the synaptic cleft when a postsynaptic cell is a muscle cell it contracts when a postsynaptic cell is a gland it secretes how do neurotransmitters affect the neuron by causing it to fire on its own action potential or receives the likelihood of it firing on its own action potential what a neurotransmitter does to a neuron is decided by receptor the ability for neurons to not fire helps with filtering overwhelming sensory info such as a concert Acetylcholine A neurotransmitter that enables learning and memory and also triggers muscle contraction Acetylcholine is released by motor neurons at the point where they synapse with muscle cells Botulinum toxin an acetylcholine antagonist; prevents release by terminal buttons. most toxic substance known what does botox do blocks release of acetylcholine so less contractions in muscles =less wrinkles glutamine involved with learning and memory, more sensitive to glutamine, better memory and learning dopamine influences movement, learning, attention, and emotion. loss of is responsible for parkinson's. chief of happiness serotonin Affects mood, hunger, sleep, and arousal who makes serotonin more? men cocaine a powerful and addictive stimulant, derived from the coca plant, producing temporarily increased alertness and euphoria. tricks pleasure center in brain and binds with presynaptic membrane where dopamine is usually reabsorbed from the synaptic cleft. blocks reuptake sites dopamine remains in cleft repeatedly stimulating it prozac and zoloft block serotonin from being reabsorbed and recycled by presynaptic cells which prolongs it affect Selective Serotonin Reuptake Inhibitors (SSRIs) a group of second-generation antidepressant drugs that increase serotonin activity specifically, without affecting other neurotransmitters morphine and heroin mimic endorphins and bind to receptor sites. in high doses gives endorphins rush which causes euphoria. slows down respiratory rate and can be fatal nicotine mimics acetylcholine by binding to the same receptors and release adrenaline and other stimulating chemicals. rapid surges the rapid depletions of these chemicals make smokers want another cigarette drugs become addictive because the body's think that there is more natural amounts of usual neurotransmitters. reduces sensitivity to drugs, needing more to have the same reaction DRD4 gene that encodes a certain class of dopamine receptor. It can be mutated for those seeking sensation, altering the mesolimbic pathway and the way sensations are rewarded caffeine a mild stimulant found in coffee, tea, and several other plant-based substances cellular waste products takes form of a variety of molecules such as adenosine adenosine when binds with receptor reduces the likelihood of a neuron initiating an action potential as more adenosine binds with more receptors we feel tired when we sleep cellular waste products are reabsorbed and recycled effects of alcohol slowed down reactions slurs speech by blocking receptors for glutamate, provides buzz by blocking dopamine reuptake, blocks pain by stimulating the release of endorphins, increases feeling of happiness by modifying the efficiency of serotonin receptors muscles generate force through contraction skeletal muscle is attached to bones by connective tissue and is controlled by individual neurons attached to each muscle fiber cardiac muscles causes the heart to pump blood blood through the body smooth muscle, involuntary, surrounds blood vessels and many internal organs which help to move blood, move food through digestive system myofibrils cylindrical organelle within muscle cells that can contract; contains repeating units, called sarcomeres in which the contraction takes place Sarcomere the fundamental unit of muscle contraction , made of actin myosin actin protein of muscle tissue; makes up the thin filaments myosin protein of muscle tissue, making up the thick filaments muscle fiber contraction Results from a sliding movement where the actin and myosin filaments merge using ATP. Globular portions of the myosin filaments can form cross-bridges with actin filaments. Reaction between actin and myosin filaments generates the force of contraction. First step of sarcomere contraction detach, link between myosin and a parallel action filament is broken as a molecule of ATP bonds to myosin Second step of sarcomere contraction reach, as the atp breaks down, energy released alters the shape of the myosin into a higher energy shape and myosin now reaches farther down the actin filament Third step of Sarcomere contraction reattach, the myosin reattaches to the actin filament at this new location Fourth step of Sarcomere contraction pull back, the myosin then snaps back to its original shape, pulling the actin filament as it does so and shorting the fiber relaxed sarcomere Actin & Myosin myofilaments lie side by side contracted sarcomere the Z lines are close together duration between contraction and relaxation is called twitch fast twitch muscle fibers that react quickly and fatigue quickly slow twitch type of muscle that contracts slowly and is fatigue resistant Oxytocin peptide hormone, produced in neurons within the hypothalamus and released by the posterior pituitary, influences trust in others, increases the social attachments, directs the ejection of breast milk, and contractions in the uterus during childbirth synthesis site of oxytocin hypothalamus target tissues of oxytocin uterus and mammary glands effect of oxytocin Effects uterus - uterine contractions during labor, direct myometrium, other effects are on limbic system in both men and women increased by touch - reflects on bonding and trust hormones chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues two systems for carrying out communication nervous and endocrine endocrine system the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream endocrine cells produce regulatory hormones target cells cells that have receptors for a particular hormone endocrine glands Glands of the endocrine system that release hormones into the bloodstream endocrine gland examples pituitary, thyroid, parathyroid, adrenal, pineal hormones help regulate homeostasis pheromones Chemical signals released by an animal that communicate information and affect the behavior of other animals of the same species. such as sexual reproduction and territory marking step one of how a hormone affect a certain cell signal is sent by a hormone being released from a gland step two of how a hormone affects a certain cell signal is received, although the hormone has no effect on most tissues it comes in contact with, cells with the right receptor in their cytoplasm or on their plasma membrane receives the signal step three of how a hormone affects a certain cell cell responds, hormone binds to receptor, causes response in target cell, can be change in gene expression in nucleus, can cause cell to start or stop producing a certain protein, alter rate of producing protein amines hormones adrenaline, hormones that are synthesized from single amino acids polypeptide hormones insulin and glucagon, chains of amino acids steroid hormones estrogen and testosterone, lipids lipid Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen. most amines and polypeptide hormones are — while lipids are not water soluble amines and polypeptide hormones — pass through memebrane cannot lipids —pass through membranes can amines and polypeptide hormones bind to receptors embedded within the cell membrane which can influence inside the cell steroids hormones bind to receptors within the cytoplasm or nucleus of the cell, always passes into nucleus once a steroid is in the nucleus it binds to DNA, influencing gene expression paracrine receptors target cell receptors for a specific hormone can be nearby hormones secreted by glands in one part of the body are able to regulate cell function in another part of the body Prostaglandins Modified fatty acids that are produced by a wide range of cells. dilation or construction of blood vessels and affecting tissue inflammation what does asprin do Inhibits prostaglandins, decreases inflammation, and slows transmission of pain to site of injury Hypothalamus underside of brain, functions as liaison between the nervous and endocrine systems and it receives input from neurons throughout the brain and rest of body. sends out appropriate hormones to regular nearly every aspect of the organisms physiology, including body temp, hunger. thirst, and water balance pituitary gland The endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands. posterior pituitary gland also known as the neurohypophysis; it is made up of nervous tissue/neurons and stores and secretes 2 hormones made by the hypothalamus (oxytocin and ADH); it is controlled by action potentials from the hypothalamus antidiuretic hormone (ADH) influences the absorption of water by kidney tubules anterior pituitary produced many hormones such as TSH, LH, FSH, prolactin, ACTH Thyroid Stimulating Hormone (TSH) causes thyroid to produce thyroxine, important in cellular respiration Follicle-stimulating hormone (FSH) stimulates development of follicles in ovaries and sperm maturation Lutenizing hormone (LH) triggers ovulation and stimulates testosterone production, works with FSH prolactin stimulates mammary glands to produce milk Adrenocorticotropic hormone (ACTH) Stimulates adrenal glands to produce cortisol and other stress related hormones Corticotropin-releasing hormone (CRH) Promotes secretion of adrenocorticotropic hormone (ACTH) growth hormone several effects, stimulating liver to release chemicals that spur growth of bones, cartilage, and other tissues excessive production of growth hormone during childhood can cause extreme growth called gigantism increased exposure to growth hormone in adulthood results in hands, face, feet growing unusually absence of growth hormone dwarfism how is pituitary dwarfism treated if caught early? shots of human growth hormone pineal gland secretes melatonin regulates sleep cycles thyroid gland releases thyroxine, influences the rate and efficient of cellular metabolism, regulates calcium levels in blood parathyroid glands regulate calcium levels in blood adrenal glands release adrenaline and cortisol (prepares body for action), regulate organisms response to stress. sit right above kidneys. pancreas releases insulin and glucagon, maintains blood glucose levels wishing a narrow range gonads release the sex steroids, including testosterone, estrogen, and progesterone, responsible for numerous physical, behavioral, and emotional features, including much sexual behavior, development, and growth Under active thyroid fatigue and weight gain overactive thyroid jitteriness, rapid heartbeat, weight loss, irritability when iodine intake is low, the thyroid is unable to produce thyroxine which causes thyroid to swell Calcitonin Lowers blood calcium levels insulin A hormone produced by the pancreas or taken as a medication by many diabetics negative feedback A primary mechanism of homeostasis, whereby a change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation. positive feedback Feedback that tends to magnify a process or increase its output. endocrine disrupters Chemicals that disrupt normal hormone functions Polychlorinated biphenyls (PCBs) A group of industrial compounds used to manufacture plastics and insulate electrical transformers, and responsible for many environmental problems. Phthalates found in cosmetics, deodorants, and many plastics used for food packaging, children's toys, and medical devices. Cause kidney & liver damage, cancer, and low sperm counts. Bisphenol A (BPA) a substance widely used in plastics and to line food and drink cans, which has raised health concerns because it is an estrogen mimic endocrine disrupters effect on mammals reproductive harm endocrine disrupters effect on fish reproductive functioning endocrine disrupters effect on invertebrates defective shells, masculinization of female genitalia, reducing fertility oxytocin posterior pituitary, uterus, breast, brain, reduce stress, more trusting "love hormone" antidiuretic hormone (ADH) posterior pituitary, kidneys, water retention in kidneys Thyroid Stimulating Hormone (TSH) anterior pituitary, thyroid, stimulates production of thyroxine, important in cellular respiration Follicle-stimulating hormone (FSH) anterior pituitary, ovaries, testes, stimulates ovary development and sperm maturation prolactin anterior pituitary, mammary glands, milk production growth hormone anterior pituitary, liver and other organs, stimulates release of chemicals that spur growth of bones, cartilage, and other tissues cortisol and adrenaline adrenal glands, smooth, cardiac, skeletal muscle, blood vessels, cell throughout body, imitates response to stress, regulates response to long term stress melatonin pineal gland, brain, regulate sleep cycle thyroxine thyroid, cells throughout body, influenced metabolic spew and efficiency calcitonin and parathyroid hormone thyroid, bones, causes bones to pick up excess calcium in blood insulin pancreas, liver, adipose tissue, skeletal muscle, take up glucose in blood which reduces its level glucagon pancreas, liver, adipose tissue, concert stored glycogen into glucose estrogen, testosterone, progesterone gonads, cells uterus, breasts, balls, puberty, pregnancy, sperm production, egg production heritable sensory autonomic neuropathy condition in which afflicted individual cannot feel pain sensory neurons affected by skin and joints affected by syphilis Interneurons are affected by parkinsons motor neurons are affected by polio Oligodendrocytes Type of glial cell in the CNS that wrap axons in a myelin sheath. Microglia Act as phagocytes, eating damaged cells and bacteria, act as the brains immune system astrocyte release gliotransmitters by expcytosis to send signals to neighboring neuron connectomes Map of the network of connections between neurons in the human brain resting potential -70 mV action potential +30 mV (depolarized) Channelopathies diseases and disorders that are the result of ion channel dysfunction Tetrodotoxin -Poisoning can result from ingestion of poorly prepared puffer fish (exotic sushi) -Highly potent toxin that binds fast voltage-gated Na+ channels in cardiac and nerve tissue, preventing depolarization - blocks action potential without changing resting potential (same mechanism as Lidocaine) -Causes nausea, diarrhea, paresthesias, weakness, dizziness, loss of reflexes. -Treatment is primarily supportive. epilepsy potassium channel mutations, muscle weakness the synapse excitatory neurotransmitters chemicals released from the terminal buttons of a neuron that excite the next neuron into firing inhibitory neurotransmitters chemicals released from the terminal buttons of a neuron that inhibit the next neuron from firing GABA An inhibitory neurotransmitter in the brain. caffeine — glutamine and — GABA activity increases, decreases Alcohol — GABA activity and — Glutamate activity increases, decreases functions of muscle generate movement, force, heat, homeostasis 2 mutates copies of them upstairs gene causes excess muscle build up muscle is composed of bundles of muscle fibers bundles of muscle fibers are composed of muscle fibers muscle fibers are composed of myofibrils myofibrils are composed of actin and myosin actin and myosin are composed of sarcomere slow fiber muscle is dark mest fast fiber muscle is light meat motor unit A motor neuron and all of the muscle fibers it innervates rigor mortis stiffness after death caused by lack of ATP, muscle remains in a state of contraction acromegaly abnormal enlargement of the extremities during adulthood when exposed to excess growth hormone Addison Disease low levels of cortisol, autoimmune disease, depression, dizziness, low blood glucose, low blood pressure chronic stress excess cortisol, high blood glucose, obesityfdwkqfejifijeoiefowojk

Prokaryotic Cell, Body Shapes, Cell Walls, Modes of Nutrition