Unit 1 Biology notes

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where they are needed Amyloplastistarch grain Mitochondrion Lysosomes small spherical membrane bound sacs with fluid inside, break down waste material Ribosomes = tiny organelles attached to the rough ER or free floating. Not surrounded by a membrane and consist of two sub units - protein synthesis Mitochondria = two membranes, inner membrane is highly folded to form cristae, central part called the matrix - site on the final stages of cellular respiration GEED Golgi Apparatus Nucleolus Nuleus Centrioles Micro tubules → Cytoplasm →→Ribsome Vesicles membrane bound sacs with fluid inside, transport materials inside the cell and secretory vesicles transport proteins to be released from the cell. Centrioles=small tubes of protein fibres, form spindles during cell division Cilia and flagella are structurally hair like extensions that stick out of cell surfaces A function of an animal cell is to synthesise proteins for use inside the cell. Proteins are synthesised on ribosomes attached to rough endoplasmic reticulum. The newly synthesised proteins are transported through the cisternae of the rough ER and packaged into vesicles. The vesicles fuse with the surface of the Golgi apparatus. The proteins are modified and then repackaged into vesicles. Secretory vesicles will transport proteins that are to be released from the cell to the cell surface membrane. They will fuse with the membrane and release the protein by exocytosis Plant cell: Call wall Golgi apparatus Chocolat Plasma membrane = selectively permeable to regulate the transport of materials into and out of the cell, and separates the contents of the cell from its environment. Vacuole membrane Cytoplasm = maintains shape, stores chemicals and metabolic reactions take place here Nucleus controls and regulates cellular activity and houses genetic material Nucleolus structure inside the nucleus, makes ribosomes and RNA Raphide crystal -Druse crystal -Mitochondrion Cytoplasm Cell wall protects and supports the cell & the plant - made of cellulose Chloroplast double membrane filled with stroma, inner membrane is a continuous network of flattened sacs called thylakoids, and a stack of thylakoids is called a granum, grana contain chlorophyll pigments - photosynthesis, light energy trapped by chlorophyll and used to produce glucose. Tonoplast = partially permeable membrane of the vacuole selective, y permeable to allow small molecules through. Chapter two Plant cell continued: Amyloplast = double membrane bound sac containing starch granules responsible for the synthesis and storage of starch granules Vacuoles= membrane bound sac in the cytoplasm containing cell sap - maintains turgor and stability ensuring rigid framework in the cell Plasmodesmata = microscopic channels which cross the cell walls of plant cells- enable transport and communication between individuals plant cells Pits pores in the cell walls of the xylem - allow water to enter and leave the xylem Prokaryotic cell: Cytoplasm Bacterial Cell Anatomy Nucleoid (DNA) Ribosomes Capsule Plasma Membrane Plasmid Flagelli Cell wall = prokaryotic cells are surrounded by a cell wall made of peptidoglycan. This protects and supports the cell. Can be distinguished into gram positive and gram negative based on structure. Capsule this is a slippery layer outside the cell wall on some species of bacteria. It protects the cell and prevents desiccation Ribosomes=smaller than ribosomes that are found in eukaryotic cells. They consist of two subunits and they are not surrounded by a membrane. Their function is protein synthesis. Nucleoid = this is the irregular shaped region that holds the nuclear material without a nuclear membrane and where the genetic material is localised. The DNA forms on circular chromosome. This is the area that controls cellular activity. Plasmid=small loops of DNA. Carry genes that may benefit the survival of the organism. Extras: Bacteria cells produce and secrete toxins that have an effect on other organisms DNA is free in the cytoplasm of the prokaryotic cell in the area called the Nucleoid A section of DNA containing a genetic code for a metabolite unwinds and hydrogen bonds break RNA nucleotides line up Messenger RNA is formed (transcription) The next process is the production of the bacterial protein This is called translation and it occurs at the ribosomes Transcription and translation can occur simultaneously because the genetic material is free in the Nucleoid surrounded by ribosomes The newly made protein/toxin is moved to the surface membrane ready to be secreted to cause infection Chapter three Specialised cells: When cells differentiate and adapt to perform specific functions Red blood cells/ Erythrocytes: Their function is to transport oxygen around the body and carbon dioxide to the lungs. They have a biconcave shape so the surface area is increased and therefore there is more room for an increased amount of oxygen. The cytoplasm contains high amounts of the pigment haemoglobin which can readily bind to oxygen No nucleus is present which makes more space inside the cell for haemogrobin molecules for maximum oxygen carrying capacity Elastic membrane allows the cell to be flexible and change shape as it squeezes through narrow capillaries Neutrophils: Their function is to destroy pathogens by phagocytosis and the secretion of enzyme They have a very flexible shape that allows them to squeeze through cell junctions in the capillary wall Their flexibility also enables them to form pseudopodia (cytoplasmic projections) that engulf microorganisms There is a large number of lysosome present in the cell, these digestive enzymes help to digest and destroy invading cells A flexible nuclear membrane further helps the cell to penetrate cell junction. It is thought that this flexibility is what causes the characteristics lobed nucleus. Sperm cells: Their function is reproduction to fuse with an egg, initiate the development of an embryo and pass on father's genes. The head contains a nucleus that contains half the normal number of chromosomes (haploid, no chromosome pairs) The acrosome in the head contains digestive enzymes that can break down the outer layer of an egg so that the haploid nucleus can enter to fuse with the eggs nucleus The midpiece is packed with mitochondria to release energy The tail rotates, propelling the sperm cell forwards and allowing it to move towards the egg Root hair cell: Their function is to absorb water and mineral ions from soil They increase surface area so the rate of water uptake by osmosis is greater Thinner walls than other plants cells so that water can move through easily Permanent vacuole contains cell sap which is more concentrated than soil, maintaining a water potential gradient Mitochondria for active transport of minerals Remember that chloroplasts are not found in underground cells - no light Ciliated epithelium: Their function is to move substances across the surface of the tissue Have cilia, which beat in a coordinated way to shift material along the surface of the epithelium tissue Goblet cells secrete mucus which helps trap dust, dirt, and microorganisms - preventing them from entering vital organs where the may cause infection Squamous epithelium: Their function is to provide a surface covering or outer layer Squamous epithelial consists of a single layer of flattened cells on a basement membrane The layer of cells forms a thin Cross Section which reduces the distance that substances have to pass through (permeable) Guard cells: Function is to control the opening of the stomata to regulate water loss Inner cell walls are thicker while the outer cell walls are thinner - difference allows the cells to bend when turgid High density of chloroplasts and mitochondria Chapter four Gram staining: Bacteria cell walls are made from peptidoglycan There are two different types: gram positive and gram negative Gram positive bacteria have a thick layer of peptidoglycan Gram negative bacteria have a thin layer of peptidoglycan If we have a Sample of bacteria, we can do an experiment to find out if it's gram positive or gram negative. This is called gram staining Method: Step one-add Crystal Violet dye to the bacteria culture. This will colour both gram positive and negative bacteria purple Step two-add grams iodine. This bonds to the Crystal violet dye Step three-Wash the bacteria with ethanol. This is a decoourising agent. When ethanol is added it thickens the peptidoglycan layer. The Crystal violet - iodine complex gets trapped inside the gram positive bacteria because the peptidoglycan is thick The crystal violet - iodine complex is washed away from one gram negative bacteria Ethanol washes away the crystal - iodine complex from the gram negative bacteria so it becomes colourless Step four the final dye, safranin, is added to the bacteria. It only dyes the decolourised gram negative bacteria pink Results: Gram positive bacteria appear purple Gram negative bacteria appear pink Gram positive: Gram positive cell walls easily absorb molecules. So will often absorb antibodies and toxins, even though they might kill the bacteria Lipopolysaccharide membrane only inside the cell. Show purple-blue when positive Photo Gram negative: Gram negative bacteria have an outer membrane made from lipopolysaccharides which prevent absorption of the antibiotics. Because of this they are often resistant to antibiotics Has a thin membrane layer inside the cell wall Shows pink-red when negative Photo Wax pencil on glass Sterilising material. Components of blood: Red blood cells - Biconcave shape Platelets - job is healing, blood clots Chapter five Plasma - liquid that carries everything in the blood White blood cells immune system What are the functions of blood? To carry oxygen around the body, Carbon dioxide back to the lungs, transports nutrients, fight infection Why do we need it? To fight off pathogens, to give the body energy Red blood cells: Make up 40-45% of the bloods volume responsible for red colour Responsible for transportation of oxygen (haemoglobin) A deficiency in iron makes it hard for us to make haemoglobin White blood cells: Responsible for dealing with infection and foreign cells They can ingest micro organisms They can change shape and squeeze their way out of blood vessels to enter our tissues Produce antibodies which bind to specific infections - part of immune system Platelets: Small pieces of cells which clot blood Bind together with strands of protein called fibrin when blood leaks Reduces opportunity for infection enter, prevents further blood loss Fibrin strands contract pulling the wound shut Plasma: Makes up around 55% by volume and is pale yellow by colour. Carries nutrients, carbon dioxide, and hormones Uses of blood: More red blood cells given to people with lack of to boost amount of oxygen being carried White blood cells used for the antibodies Plasma used for people who have lost it like burn victims Blood disorders: Sickle cell disease- inherited, shaped like sickles, cannot carry oxygen meaning person can deoxygenate quickly Haemophilia- inherited, blood cannot clot, flows instead of stopping Anaemia Lack of healthy blood cells to carry adequate oxygen Leukaemia- cancers that affect blood cells, mostly white blood cells and bone marrow. The cells often divide too quickly and don't develop properly, which compromises your immune system and ability to fight infection Types of white blood cells: Neutrophils = move around the body in the blood and seek out foreign material Macrophages the biggest blood cells. Some live in different parts of the body and help to keep it clean. Others swim around cleaning up white blood cells that have been damaged Basophils = function in allergic reactions, they release histamines Lymphocytes work on bacterial and viral infections, two types: B cells produce antibodies. Each cells watches out for a particular pathogen, when seen they produce more antibodies T cells = look for invading hiding pathogens that are different to normal healthy cells and kill them No antigen = foreign cell. Epithelial tissue: There is three types - Squamous epithelial Ciliated columnar Endothelial tissue Squamous epithelial: Typically lines blood vessels and body cavities and regulates the passage of substance into the underlying tissue Type of flat cell found throughout the body including in the mouth, on the lips, and on the cervix Regulates the passage of substances into the underlying tissue Nucleus, Chopter six Apical Surface Basolateral Surface Basement Membrane Ciliated columnar: Found in sperm ducts, lining the trachea, bronchi, kidney tubules, respiratory tract, and oviducts. Main function is it secretes mucus which helps to trap the dust particles and thus clears the respiratory tract O Sasa Granule Columnar C Basement Membrane Figure: CILIATED COLUMNAR EPITHELIUM Endothelial tissue: Form a single cell layer that lines all blood vessels and regulates exchanges between the bloodstream and the surrounding tissues Signals from endothelial cells organise the growth and development of connective tissue cells that form the surrounding layers of the blood vessel walls Found in most arteries, veins and capillaries of the brain, skin, lung, heart and muscle elastica interna fibroblast endothelial cells. Lumen smooth muscle cells intima media adventitia Conditions: Emphysema a lung condition that causes shortness of breath, the alveoli are damaged Most people that get it are smokers, or people who have had long term exposure due to air pollution, chemical fumes or dusts from environment. Mostly affects men but can affect women over 40. COPD (chronic obstructive pulmonary disease), name for a group of lung diseases such as emphysema and chronic bronchitis, causes breathing difficulties. Mainly affects middle aged or older adults who smoke however many people can have it without realising Lungs become inflamed and damaged Atherosclerosis = build up of fats, cholesterol and others substances in and on the artery walls People who are 65+, smokers, have high cholesterol and high blood pressure Chapter seven Tissues, blood vessels & atherosclerosis: What is a tissue? Specialised cells grouped together with the same area Four main types of tissue: Muscle tissue = cells that are long and fibrous. These cells are ready for contraction. Connective tissue makes up a connective web inside our body. Holding our body parts together and providing support are the main jobs of this tissue. Nervous tissue = is found within the nervous system and is made up of unique specialised cells. Transmits signals from nerves to the spinal chord and brain. Epithelial tissue = joined together tightly making a protective layer for the body, in the form of skin. Can also be found lining some internal organs. Epithelial tissue: Epithelial tissue is made up from epithelial cells. These cells can be squamous, cuboidal, columnar, or pseudostratified making a single or stacked continuous sheet. Common features: Lack blood vessels Have a rich supply of nerves Cells can reproduce Important functions: Protection Sensory functions Secretions Absorption Squamous epithelial tissue: Present where transportation of substances occur through a selectively permeable surface Made of flattened specialised cells ideal for rapid diffusion of substances. Found in alveoli, provides a short diffusion pathway and allows rapid diffusion of oxygen and Carbon dioxide. Smoking irritates and causes inflammation and scaring of squamous epithelial tissue in the lungs damage to the alveoli causes emphysema Alveoli walls become thicker due to scarring and produce more mucus, this is chronic bronchitis Symptoms are all associated with chronic obstructive pulmonary disorder Columnar epithelial tissue: Where absorption and secretion occur, as the inner lining of the intestine (tall epithelial cells are present) Consist of cilliated cell with cilia covering the exposed cell surface They line the trachea in order to protect the lungs from infection - sweep pathogens away from the lungs Goblet cells are also present in the respiratory tract. They secrete mucus to help trap unwanted particles to prevent the bacteria from reaching the alveoli Endothelial tissue: Consists of specialised epithelial Cells that line inside of blood vessels also found on the inner wall of the heart chambers and the interior surface of lymphatic vessels Forms an interface between circulating blood or lymph in the lumen and the rest vessel wall Single layer of flat, long squamous cells called endothelial cells Vital because it's a protective layer that assists in efficient blood flow to organs and cells in the body Semi selective barrier between the vessel lumen and surrounding tissue, controlling the passage of materials and the transit of white blood cells into and out of the bloodstream. Endothelium cells help control vasoconstriction and vasodilation therefore regulating blood flow - regulates clotting Endothelial dysfunction the endothelium is weakened and vasodilation is impaired and the arteries begin to lack the ability to dilate properly Significant predictor of coronary artery disease and atherosclerosis Can be caused by diabetes or hypertension as well as smoking - lifestyle changes can be made to correct dysfunction Chapter eight Blood vessels continued: Arteries and veins are made of the same tissue in different proportions. They both have an outer connective tissue layer and elastic tissue. The middle layer also has connective and elastic tissue along with smooth muscle. The middle layer is thicker in arteries to maintain elasticity and blood pressure. The inner layer is endothelial tissue. Capillaries only have one layer of endothelium. They provide a short diffusion pathway for products of digestion and movement of blood plasma and tissue vivid Artery: Function carry blood away from the heart (pulmonary goes to lungs) Thick, muscular walls to help maintain a high blood pressure Small lumen Vein: Carry blood towards the heart (pulmonary has oxygenated) Thin walls, with values, prevents backflow Large lumen Capillary: Allows diffusion of gases and nutrients from the blood into body cells Very thin with a small lumen - allows cell at a time pass Walls are made of a semi-permeable membrane to allow transport of gases and nutrients into and out of blood Atherosclerosis: A potentially serious condition where arteries become clogged with fatty substances called plaques (atheroma). Plaque is made up of fat, cholesterol, calcium and other substances found in the blood. These fatty deposits cause the arteries oo harden and narrow, restricting the blood flow and oxygen supply to vital organs, and increasing the risk of blood clots (thrombosis) that could potentially block the flow of blood to the heart or brain. It also means the heart has to work harder. Effects: Atherosclerosis can lead to a number of serious conditions such as: Coronary heart disease- the main arteries that supply your heart become clogged Angina - short periods of tight, dull or heavy chest pain caused by coronary heart disease, may precede a heart attack Heart attack - blood supply to your heart is blocked, causing sudden crushing or indigestion like chest pain that can radiate to nearby areas, as well as shortness of breath and dizziness. Strokes - the blood supply to your brain is interrupted, causing the face to droop to one side, weakness on one side of the body, and slurred speech. Risk factors: Cigarette smoke can increase the risks of developing atherosclerosis because smoking increases the thickness of blood. This thick blood leads to atheroma (fatty deposits) to build up on the walls of arteries. Smoking also increases blood pressure and heart rate, which can damage the endothelium. High levels of low density lipoproteins (LDL) cholesterol, also known as bad cholesterol, can increase your risk of atherosclerosis. Development: Damage to endothelial tissue lining of artery Raised blood pressure LDL cholesterol accumulates in artery wall Increase risk of blood clotting in the artery Narrowing of artery, loss of elasticity restricts blood flow Inflammation results so white blood cells move into artery wall Build up of LDL cholesterol, white blood cells, calcium salts and fibres leading to atheroma Neurons: Nerves carry electrical impulses Sensory neurons pass an impulse to relay then to motor Nerve cells: Chapter nine These are extremely elongated cells They have many branches at both ends called dendrites which connect to other cells and effectors The long axon is covered in fat (myelin sheath) to prevent the electrical impulse affecting surrounding parts of your body Their functions are to carry nerve impulses around your body Types of nerve cells: Journey of an impulse from a stimulus: Stimuli is received by sensory neurone which passes an impulse onto the relay neurone in the CNS this is then passed onto the motor neurone which is revived by the effectors causing a response Nervous tissue: Nervous tissue is made up of a bundle of nerve cells, and this is called a nerve The specialised cells are specifically adapted to conduct electrical impulses Nerves can be very long eg. Sciatic nerve Nerve cell structure: Cell body (soma) = nucleus and large amounts of RER associated with production of proteins and neurotransmitters. Dendrons = carry nerve impulses towards the cell body Axon single long fibre that carries nerve impulses away from the cell body Schwann cells surround axon by wrappi around many times, protecting it and providing electrical insulation. Phagocytosis and nerve regeneration Myelin sheath forms covering of axon and made of membranes of Schwann cells. Rich in lipid known as myelin. Can be myelinated or unmyelinated. Myelinated neurones transmit nerve impulses faster. Nodes of Ranvier = gaps between adjacent Schwann cells where there is no myelin sheath. Myelin sheath: Most nerve cells are myelinated, the sheath protects the axons, a lot like the insulation around an electrical wire consists of flattened Schwann cells. Nerves that aren't myelinated are usually small in diameter and responsible for transmitting pain such as aches and soreness rather than a sharp pain detect temp changes Myelinated: Have a sheath White Transmit impulses fast Have nodes of ranvier Unmyelinated: No sheath Grey Transmit impulses slower No nodes of ranvier ' Myelinated neurones: When an impulse travels along a nerve, ions have to enter and leave the axon at various points. lons are charged particles, meaning that at these the axon becomes depolarised. This is how the impulse travels along the neuron Saltatory conduction: The myelin sheath provides insulation which means the charge is forced to jump from one node to the next instead of travelling the whole length of the axon. This makes transmission much faster. Muscles: Striations Nucleus Muscle Fiber Myofibrils Filaments containing actin and myosin Sliding filament theory: A muscle fibre contracts when myosin filaments pull actin filaments closer together and thus shorten sacromeres within a fibre. There are five stages: resting, excitement contraction, contraction, recharge, and relaxation. Chapter ten When all the sacromeres in a muscle fibre shorten, the fibre contracts A sacromere is the basic contractile unit of a myocyte (muscle fibre) - made of striated muscle Structure of a Skeletal Muscle Sacromeres are composed of two main protein filaments - actin & Myosin, these are the active structures responsible for muscular contraction. Multi nucleated: ATP = adenosine triophosphate, it is the source of energy for use at cellular level Calcium helps muscles to contract as well as helping blood clotting - Sarcoplasmic Sument 2 dec I band Sarcomare H zone A band Sercolemma NO I band Thick (min) 4 M Because the muscle cell is so large, it needs more myonuclei Multiple nuclei mean multiple copies of genes, permitting the production of the large amounts of protein and enzymes needed for muscle contraction. Striated appearance: The striated appearance of skeletal muscle tissue is a result of repeating bands of the proteins actin and myosin that are present along the length of myofibrils. Dark A bands and light I bands repeat along myofibrils, and the alignment of myofibrils in the cell causes the entire cell to appear striated or banded. Myofibrils: The myofibrils are made up of thick and thin myofilaments, which help give the muscle it's striped appearance. The thick filaments are composed of myosin, and the thin filaments are predominantly actin, along with two other muscle proteins, tropomyosin and troponin. Sarcolemma: The fine transparent tubular sheath which envelops the fibres of skeletal muscles The sarcolemma generally maintains the same function in the muscle cells as the plasma membrane does in other eukaryote cells. It acts as a barrier between the extracellular and intracellular compartments, defining the individual muscle fibre from its surroundings. Helps spread electrical impulse throughout the cell. Sarcoplasmic reticulum: The sarcoplasmic reticulum (sr) is a membrane-bound structure found within muscle cells. It controls the uptake and release of calcium ions This controls the ATPase activity and therefore the contraction of the muscle Mitochondria: To meet the energy demand, muscle cells contain mitochondria. These organelles commonly referred to as the cells 'power plants', convert nutrients into molecule ATP Neuromuscular junctions: A neuromuscular junction is a chemical synapse formed by the contact between a motor neuron and a muscle fibre. It is at the neuromuscular junction that a motor neurone is able to transmit a signal to the muscle fibre, causing muscle contraction. Muscles: Continued.... T-tubules: The transverse tubular system is a network of interconnecting rings, each of which surrounds a myofibril. It provides an important communication pathway between the outside of the fibre and the myofibrils, some of which are located deep inside the fibre. As ATP ADP and Pocking My cross bridge ataches to the acti PSS Chapter eleven As new ATP taches to the myosin head Copyright ©2001 Banjamin Cummings, an impnt of Addison Waskay Longman, Inc Working stroke the myosin head pivot of the actament Types of fibres: Skeletal muscles are made up of two types of muscle fibres slow twitch & fast twitch Large Store of myoglobin Supply of glycogen Rich supply of blood vessels Numerous mitochondria ATP Different muscles have different proportions of these fibres Slow twitch: Contract slowly, less powerful over long periods of time. Suited for aerobic respiration Fast twitch: Contract rapidly, short time, very powerful Suited for anaerobic respiration Thicker and more myosin fibres A high concentration of enzymes suited for anaerobic respiration A store of phosphocreatine. ADP & ATP Summary: Muscles are made up of: Bundles of muscle fibres Composed of individual muscle fibres (muscle cells) Composed of individual myofibrils Which have sections called sacromeres Myofibril is completed of two contractile filament proteins - actin and myosin. Sarcomere are sections of myofibril involved in muscle contractions and relaxing. Once sarcomere section = z-line to z-line Sarcomere length gets shorter as the muscle contracts Action potential: There are different parts to nerve transmission and action potential. Depolarisation: lons enter and leave the axon at the nodes of ranvier Since ions are charged particles, this causes a shift in polarity (charge) at these points. This is called a potential difference or action potential A nerve impulse is a self-propagating wave of electrical disturbance that travels along the surface of the axon membrane. It is not an electrical current, but a temporary reversal of a charge at each node of ranvier depolarisation. This reversal is between two states called the resting potential and the action potential Chapter twelve Axon membrane: Contains channel proteins and pumps for ion transport: Na+ ion channel protein- usually closed K+ ion channel protein- usually open Na+/K+ pump - requires energy (ATP) +30 Membrane potential (mv) -70 Action potential Depolariz 2 3 4 S time (ms) Resting potential 6 Resting potential: The term given to the charge of a neutron not transmitting an electrical impulse when an rest It has a negative charge because the pump is actively transporting K+ and Na+ ions across the axon membrane out of the cell. The relative charge is more positive outside of the cell compared to inside, creating the negative resting potential - it is polarised Because the K+ channels are usually open, they can re-enter the cell. Na+ channels are usually closed, so they do not re-enter. - Threshold: A stimulus causes a receptor cell to generate an action potential, across the axon membrane. There is a slight change in charge across the membrane. If this change reaches the threshold (-50mV) the Na+ channels open Depolarisation: Now the Na+ channels are open, ions rush in making the inside of the axon more positively charged than the outside. This creates a potential difference of +30 to +40mV. The membrane is depolarised. Repolarisation: After this, the Na+ channels close, and K+ channels open, allowing potassium ions to leave the cell. The inside of the cell becomes relatively more negatively charged again. The axon is repolarised. Recovery: This repolarisation over-compensates a little, becoming hyperpolarised so some K+ re-enters the cell to restore the resting potential. Saltatory conduction: This happens all the way along the unmyelinated neurones, but only at the nodes of ranvier in myelinated neurones. Nervous impulse: When the action potential reaches the end of a neurone, it triggers the transmission of either an electrical signal or chemical message across the synapse to the next neurone. Multiple sclerosis: MS is a lifelong condition that affects the brain and nerves Chapter thirteen It can cause problems with vision, arm or leg movement, sensations or balance. Commonly diagnosed in people from their twenties to their forties Symptoms: Fatigue Difficulty walking Vision problems Problems controlling the bladder Numbness or tingling in different parts of the body Muscle stiffness and spasms Problems with balance & co-ordination Problems with thinking, learning and planning Causes: MS is an autoimmune condition Something goes wrong with the immune system and it starts to attack healthy parts of the body - in this case, the brain or spinal chord The immune system attacks the myelin sheath meaning the nerves underneath become slow or disrupted. Treatments: No cure for MS only treatments Treatments could include: Treating relapses with short courses of steroid medicine to speed up recovery. Specific treatments for individual MS symptoms. Treatment to reduce the number of relapses using medicine called disease-modifying therapies. Chopter fourteen Synapses: How does MS affect the transmission of nervous impulse? No myelin sheath meaning impulses may get lost, or take longer to get to the place it's meant to be Synapses are the gaps between each neuron The pre-synaptic membrane is the end of neuron which impulse exits from The post synaptic membrane is the beginning of the neurone the impulse enters Journey: When an impulse arrives at the pre-synaptic membrane, ie triggers the release of neurotransmitters from vesicles The neurotransmitters diffuse across the synaptic cleft, before binding with receptors on the post-synaptic membrane These receptors are only found on the post-synaptic membrane, so the impulse can only travel in one direction. Neurotransmitters: Neurotransmitters are chemical messengers that continue the transmission of nervous impulse across the synapse Acetyl choline was the first neurotransmitter to be discovered and had many functions, including the stimulation of muscles. It is usually made in the brain, and broken down in the synaptic cleft by acetylcholineterase Botulinum toxin is a neurotoxic protein produced by the bacterium clostridium botulinum. It can paralyse respiratory muscles, causing suffocation and death. This is a disease called botulism. Botox procedures use the same bacteria to paralyse targeted muscles. The toxins attack the nervous system (CNS) and causes paralysis. The bacteria produces toxins in food, wounds, and in infants (intestines). Blocks acetylcholine from being released therefore no impulses can be passed from one neurone to another. Parkinson's disease: Parkinson's is associated with the death of dopamine secreting neurones in the brain causing reduced levels of dopamine Dopamine = neurotransmitter that helps control movement and emotional responses Symptoms muscle tremors, stiffness of muscles, poor balance, difficulties with speech and breathing, depression Treatment: There is no cure for Parkinson's A variety of treatments are available which aim to increase concentrations of dopamine in the brain. Dopamine cannot be administered because it cannot move from the blood stream to the brain. However, the molecule L-dopa uses the body to generate its own dopamine. Dopamine agonists have a similar shape to dopamine so can mimic it to help treat Parkinson's. Imbalances of neurotransmitters can cause ill health Excitatory neurotransmitters increase the likelihood of an action potential for example dopamine Inhibitory neurotransmitters decrease the likelihood of action potential for example serotonin Agonists: substances that bind to synaptic receptors and increase the effect of the neurotransmitters eg. Opiates, MDMA - enhance the feeling of pleasure. Antagonists: substances that also bind to synaptic receptors buy decrease the effect of neurotransmitters eg. Beta blockers. Chopter fifteen Neurotransmitter types: Serotonin Carries messages between nerve cells in the brain and throughout the body Once the message has been carried, serotonin is usually reabsorbed by the nerve cells It plays a key role in the body functions: mood, sleep, digestion, nausea, wound healing, bone health, and blood clotting By using ecstasy (MDMA) it can deplete your serotonin levels This because it blocks the uptake SSRI is short for Selective Serotonin Reuptake Inhibitors They are mainly prescribed to treat depression, used mostly with talking therapies like cognitive behavioral therapy They are anti-depressants It inhibits the reuptake of serotonin, therefore increasing serotonin activity and then the serotonin can pass further messages between nerve cells. Nicotine: Alters the rules for pre-synaptic plasticity resulting from timed pre- synaptic and post synaptic activity and increases LTP threshold by reducing dendritic calcium signals Can change the way synapses are formed, which can harm the parts of the brain that control attention and learning. Chapter sixteen ECC's: Electrocardiograph measures the electrical activity of the hears over a period time P wave - depolarisation of the atria (systole) in response to the SA nose triggering QRS wave - depolarisation of the ventricles (bigger muscle mass so bigger wave) triggers main pumping contractions. T wave - repolarisation of the ventricles (diastole) Normal heart beat would be 80bpm Tachycardia - heart rate is above 100bpm meaning it beats too fast Bradycardia - heart beats too slow, below 60bpm - not usually dangerous Ectopic heartbeat early heartbeat followed by a pause, usually requires no treatment unless it's severe Fibrillation- an irregular heartbeat will disrupt the rhythm of the heart, severe cases can be dangerous and potentially fatal. Tachycardia can be caused by exercise, high emotion or fever Bradycardia is most common in athletes An irregular heartrate can also be called arrhythmia EEG: Electroencephalograph - measures the electrical activity of the brain over a period of time. It can be used for diagnosing problems, things like seizures and things