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Pharmaceuticals The central and peripheral nervous system The central nervous system is essential to human function o It is the master control centre for our emotions, senses, responses, reactions, body balance like temperature and heartbeat as well as the activities of our muscles and glands o The nervous system controls and coordinates our bodily functions The nervous system is divided into two main groups o The Central nervous system (CNS) comprises the brain and spinal cord and acts as the control centre for the nervous system. Information from the senses is interpreted here and command actions are issued to other parts of the body o The Peripheral nervous system (PNS) comprises of the connecting nerves which link the brain and spinal cord to and from the rest of the body. Nerves connecting to the brain are called cranial nerves Nerves connecting to the spinal cord are called spinal nerves. The PNS carries the messages from the sensory organs along sensory nerves to the CNS and carries messages from the CNS along motor nerves out to the muscles and glands Between motor nerves and sensory nerves are interneurones The sense organs o Human senses enable us to be aware of environment See Touch Taste Hear Smell o Sense organs are made up of sensory cells that receive and convert information from our sense into electrical impulses for the brain o The role of sense organs in the body is to respond to the environment and to relay these changes to the central nervous system The neurone consists of a cell body from which long thin strands reach out. o Axon away from cell body Longer than dendrite Myelin insulator Efferent transmission o Dendrite Towards cell body Shorter than axon Afferent Transmission o o There are billions of neurones in the body, and so we barely grow new neurones ( once destroyed, they are gone forever) o The myelin is used as an insulator to stop impulses jumping from one neurone to another o As the nerve impulse passes, there is a flow of sodium and potassium ions across the axon membrane. For a short time, the outside is made negative and the inside positive. After the impulse has passed by, there is a brief period during which another impulse cannot pass, as the cell pumps the ions back to where they came from. Types of nerve cells o Sensory nerve cells Carry impulses from receptors in sense organs to CNS Afferent transmission o Motor neurones Carry impulses out from the brain or spinal cord to the muscles or glands. The muscles and glands are called effectors o Interneurones Connect the sensory neurones to the motor neurones Transmit message from the senses to the effectors via CNS Often Small Reflex Arc o Reflexes are actions that your body performs without you having to think about them o A reflex arc is the nervous pathway along which the impulses travel for a reflex action Examples are: Knee Jerk Eyes to light Nervous messages o The nervous impulse arrives at the synapse at the end of a neurone o The impulse triggers some chemical messengers at the end of the neurone to release chemicals (called neurotransmitters) into the synaptic gap o These chemicals travel across the gap and stimulate a new impulse in the adjoining neurone o Common neurotransmitters in the human body are: Acetylcholine-muscle control Noradrenaline-Adrenalin Dopamine o Drugs and medicines can affect the transmission of nervous messages across the synaptic gap Transporting pharmaceuticals in the body The circulatory system is a transport system where blood carries oxygen, carbon dioxide, hormones and other materials It carries supplies to the body's cells and removes waste products The system depends on the pumping of the heart to maintain delivery and removal of essential substances Blood vessels: The human body has three main blood vessels o Arteries Always carry blood away from heart Carries blood under high pressure Three layers of thick, sturdy, elastic muscular walls o Veins Always carry blood to heart Also has three layers of tissue but not as thick as arteries Contains valves to stop back flow of blood. o Capillaries Link Arteries to veins Tiny, one cell thick Extend into all areas of the body Do not contain muscular walls or valves Main function is to diffuse substances between the blood and the cells Components of blood o 55% plasma 90% water Salts like sodium, potassium, calcium, magnesium, chlorides, bicarbonate which assist in membrane functioning and osmosis. Proteins like albumin fibrinogen, immunoglobulins which help in maintaining body immunity and blood clotting Other substances such as glucose, waste, respiratory gases and hormones o 45% blood cells Red blood cells transport oxygen and carbon dioxide Lack nucleus Made in bone marrow Relatively small and flexible Inside is an iron-rich substance called haemoglobin White blood cells There are five types each with a specific job Basophil Mast cell Eosinophil Neutrophil Monocyte Fighting infection Preventing cancers Identifying tissue damage Also made in bone marrow Not confined to blood vessels The circulatory system is particularly important at distributing drugs to parts of the body Pharmaceuticals to reduce pain and inflammation The human body's first line of defence is the system of the skin o Skin coated with antibacterial and antifungal acids made by swat and glands on surface o Moist areas encourage natural bacteria to grow to help defend the body o Membranes covered with mucus coat o Body fluids like saliva, urine, perspiration, tears and nasal secretions contain antimicrobial substances to flush the body clear at these sites of entry Damage to skin or other membranes stimulates inflammatory response o This is the body's second line of defence Stages in the inflammatory response o Release of chemical alarm signals o Blood vessels dilate and become more permeable o White blood cells enter the tissue o Inflammation is present o Spread of damage is restricted Advantages of inflammation Disadvantages of inflammation Chemical alarms like histamines are released to attract defence agents to the site of infection Heat from increased blood flow to area attracts antimicrobial agents and dilated vessels enables them to reach affected tissues. A higher metabolic rate also speeds up cell repair Heat can upset the body's temperature regulator and may produce fever. Very high fevers can denature enzymes in the body, damage body proteins and in severe cases may result in death Swelling and redness draw more nutrients, oxygen, white blood cells and plasma to the site of tissue damage which assist in neutralising toxins and cleaning up the area. Swelling can cause temporary loss of movement in joints and pain. Long-term swelling may result in permanent tissue damage. Some histamines are present in allergic reactions which can cause runny noses, hives, cramps, swelling or diarrhoea Prostaglandins are local hormones derived from fatty acid molecules that modify the effects of other hormones. o They are produced by cell membranes not glands o They help Promote inflammation Enhance pain by making pain receptors more sensitive Produce fever by their actions in the hypothalamus Regulate blood pressure Promote blood clotting Start muscle contraction during childbirth Control the sleep/wake cycle An analgesic acts as a prostaglandin inhibitor which reverses its effects o Aspirin is an analgesic with the chemical acetylsalicylic acid Bacteria Bacteria belong to the kingdom Monera and are commonly called prokaryotes A prokaryote is an organism whose small, simple cells lack membranes around their nucleus, mitochondria and chloroplasts Bacteria can be classified based on their shape o Cocci Small spherical-shaped bacteria often found in chains or clusters o Bacilli Rod-shaped bacteria commonly found in soil and can also be found singly, in pairs or in chains. o Spirilla Curved or spiral-shaped bacteria which is the least common Bacteria have unique shapes which is the main means used in their naming and classification. Structure of bacteria o Flagella o Pili o Capsule o Cell wall o Cell membrane o Cytoplasm o Plasmid o Nuclear area containing DNA Bacterial Reproduction uses the process of binary fission o Reproduction in bacteria will be affected by a number of conditions Temperature Moisture conditions Available food supply Penicillin is obtained from a fungus (mould) and is a good antibiotic as it acts on bacterial cells in the act of dividing.