Yr 10 Biology Human Core Notes 2024 - PDF

The Human Core Notes 2024 1. Identify different human organ systems (skeletal, muscular, circulatory, respiratory, nervous, digestive, reproductive, immune) You will need to be able to identify the eight different human organ systems, but are not expected to write about what they contain or their fu...

The Human Core Notes 2024 1. Identify different human organ systems (skeletal, muscular, circulatory, respiratory, nervous, digestive, reproductive, immune) You will need to be able to identify the eight different human organ systems, but are not expected to write about what they contain or their function. 2. Explain the role of the circulatory system. The circulatory system carries oxygen, nutrients, and hormones to cells, and removes waste products, like carbon dioxide 3. State the 3 components of the circulatory system are the blood, heart, blood vessels. The circulatory system comprises the heart, blood and blood vessels. These work together to carry out a function- this is the definition of a human organ system; a group of tissues and organs that work together to carry out the same functions. 4. Explain the structure and function of the blood (red blood cells, white blood cells, platelet, plasma) Blood is mostly made up of plasma. This is a pale yellow liquid that the components of blood (including hormones, salts, blood cells, nutrients and gases) are contained in. It makes up about 55% of what we think of as blood. The blood cells that are found within the blood are: Red blood cells - These are used to transport oxygen to cells and remove carbon dioxide to be excreted out of the body at the lungs. White blood cells - These are used to defend the body against pathogens Platelets - These cause clotting of the blood, this stops bleeding when damage occurs. 5. Explain the structure and function of the blood vessels (arteries, capillaries, veins) Artery - Arteries transport blood away from the heart. The blood is under high pressure and so they have thick outer walls and thick layers of muscle and elastic fibres. They carry oxygenated blood except for the pulmonary artery. Vein - Veins carry blood towards the heart. The blood in veins is under low pressure compared to arteries. They therefore have thinner walls and a thinner wall of muscle and elastic fibres. However they also contain valves as pictured. These stop the backflow of blood. (when the heart is not contracting). They carry deoxygenated blood except for the pulmonary vein Capillary - These are very small, thin walled blood vessels that connect arteries and veins, that allow for the exchange of oxygen into cells from capillaries and carbon dioxide from cells into the capillaries. Nutrients and waste materials are also exchanged across the capillary walls. Note: the veins are the only blood vessel that has valves! 6. Explain the structure and function of the heart (aorta, pulmonary artery, pulmonary vein, vena cava, left atrium, left ventricle, right atrium, right ventricle, septum) The diagram of the heart is shown in anatomical pictures as if you were looking at someone lying on their back. So when you go to label the left side of a diagram, you will actually be labelling the right side. A tip to help you remember which is which is to look for the thickest wall- the left side has a thicker outer wall as it pumps blood at higher pressure. The chambers at the top of the heart are called atrium and the chambers at the bottom of the heart are called the ventricles. The left and right side of the heart are divided by the septum. This is so no mixing of deoxygenated and oxygenated blood occurs. The right side of the heart (ventricle) pumps blood to the lungs to reoxygenate the blood. The left side of the heart (ventricle) pumps oxygenated blood to the body - so that our cells can have a fresh supply of oxygen for respiration. The valves of the heart open and close in a rhythmic fashion depending on the contracting and relaxing of the heart. When they close, the valves prevent the backflow of blood, and when they open, they ensure the blood is moving in the correct direction. Aorta - the largest artery in the body that leaves the left ventricle taking oxygenated blood to the body. Pulmonary artery - carries deoxygenated blood from the heart to the lungs. Pulmonary vein - carries oxygenated blood from the lungs back to the heart. Vena cava - two large veins that return deoxygenated blood from the body to the heart. Left atrium - receives the oxygenated blood from the left and right pulmonary veins. Left ventricle - thickest of the heart chambers that pumps oxygenated blood all around the body. Right atrium - receives deoxygenated blood from the body through the vena cava. Right ventricle - pumps deoxygenated blood to the lungs. Septum - separates the atria and ventricles in such a way that it forms a barrier between the heart chambers and this prevents mixing of oxygenated and deoxygenated blood. Direction of blood flow through the heart: Blood enters the vena cava → right atrium → through the tricuspid valve → right ventricle → pulmonary valve → pulmonary artery → to lungs for reoxygenation → pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta → rest of the body 7. Discuss the adaptations of red blood cells and how they increase the rate of oxygen transport. Red blood cells have haemoglobin to bind to the oxygen so it may be transported to cells. No nucleus to allow more space for haemoglobin to bind to oxygen, which allows them to carry oxygen to the cells; they have a thin outer membrane shorter distance for oxygen to move into / out of the red blood cell to let oxygen diffuse through easily. The shape (bi-concave disc) increases the surface area to allow more oxygen to be absorbed efficiently. Small and flexible shape means they can squeeze through the narrow capillaries. 8. Explain the role of the respiratory system from breathing to gas exchange The respiratory system is involved in breathing and gas exchange. Breathing, also known as ventilation is the action of taking in air that is rich in oxygen (inhalation) and removing air that is rich in carbon dioxide (exhalation). Ventilation involves respiratory muscles, including the diaphragm. Gas exchange is the process of swapping oxygen and carbon dioxide across the alveolar membrane and the bloodstream. Blood low in oxygen and high in carbon dioxide enters the capillary. Carbon dioxide moves from the blood in the capillaries across the alveolar membrane to the air in the alveoli. As we breathe out, the air rich in carbon dioxide is removed from our respiratory system. Meanwhile, oxygen from the air that we breathe in, moves from the alveoli across the alveolar membrane, to the blood in the capillaries. Red blood cells then transport oxygen to our body tissues. 9. Explain the structure and function of the respiratory system (trachea, rings of cartilage, bronchi, bronchiole, lungs, alveoli, diaphragm, ribs) STRUCTURE FUNCTION Nasal cavity Includes the nose and mouth. Draws in air, filters it and moistens it before it enters the trachea Trachea The wind pipe that connects the throat with the bronchi. Contains mucus to filter the air before entering the lungs Rings of Prevents the trachea from collapsing/keeps the trachea open Cartilage Bronchi There are two of these tubes, one goes to each lung Bronchioles Smaller tubes that branch off from the bronchi and take air to the alveoli Alveoli Air sacs. Where gas exchange takes place (ie carbon dioxide leaves the blood and oxygen enters the blood)  Diaphragm A large sheet of muscle that aids breathing eg when it moves down air is drawn into the lungs Lungs Two large spongy organs that contain the alveoli and bronchioles. Ribs Ribs are bones that protect our major organs including the heart and lungs 10. Explain how and where gas exchange occurs at the alveoli Step 1: Blood low in oxygen, and high in carbon dioxide enters the capillary. Step 2: Carbon dioxide moves from the blood in the capillaries to the air in the alveoli. Step 3: Oxygen from the air we breathe in moves from the alveoli to the blood in the capillaries. Step 4: Oxygen is transported by the red blood cells to our bodies tissues. 11. Discuss the adaptations of the alveoli and how they increase the rate of gas exchange ​ There are millions of alveoli in each lung, providing a large surface area for gas exchange. ​ The round shape increases the surface area for gas exchange. ​ They have a moist lining (surfactant) so oxygen dissolves first, speeding up diffusion into the blood. ​ The production of surfactant (a soapy substance that the alveoli secrete) means the alveoli don’t stick together when the lungs deflate, making it easier for the lungs to re-inflate. ​ They have thin membranes reduces the distance for oxygen to move across to the blood in the capillaries. ​ Alveoli are surrounded by a network of capillaries which increases the rate that gas exchange can occur 12. Explain the difference between respiration, gas exchange and breathing. ​ Respiration is a chemical process in a cell that converts glucose in the prescence of oxygen to create energy (CO2 and H2O is also given off) ​ Breathing is the process of taking air in (inhalation) and out of the lungs (exhalation) ​ Gas exchange is the process of exchanging oxygen and carbon dioxide between the bloodstream and the alveoli of the lungs 13. State the purpose of digestion. Animals need to consume food to gain nutrients needed to carry out the life processes that are common to all living organisms (MRSGREN). 14. State the different types of nutrients There are six main types of essential nutrients, which can be broadly grouped in two categories. 1. Protein 2. Carbohydrates 3. Fats 4. Vitamins 5. Minerals 6. Fluid Macronutrients = Protein, carbohydrates, fats Micronutrients = Vitamins, minerals The body needs all of these to function correctly and maintain overall health and they must be obtained from the diet. 15. Label the parts of the digestive system. Mouth, Oesophagus, Stomach, Small intestine, Large intestine, Rectum, Anus 16. Discuss the process of digestion in humans, including ingestion, digestion, absorption and egestion Ingestion: Taking food into the mouth Digestion: The process of breaking down LARGE INSOLUBLE nutrients into SMALL SOLUBLE nutrients that can be absorbed and used by cells. Absorption: Taking digested food into the blood Egestion: Removing undigested food Mouth – Ingestion and digestion Food is masticated (chewed) here. The ingested food is formed into a bolus (ball) by the tongue. The salivary glands produce saliva, which contains the enzyme amylase (an enzyme is a protein that helps to break down substances). This begins the process of chemical digestion of carbohydrates. Saliva also lubricates the bolus and aids swallowing. Oesophagus The bolus of food moves down the oesophagus in a wave-like motion called peristalsis. Stomach - Digestion  The stomach is a large, elastic bag that can expand to hold many litres of food. The interior of the stomach is lines with holes, called gastric pits. Cells within these secrete three types of fluid, known together as gastric fluid. 1.​ Hydrochloric acid – corrosive, creates optimum acidic conditions for enzymes, kills many pathogens (disease-causing micro-organisms). 2.​ Pepsin – this enzyme catalyses the breakdown of proteins into amino acids. 3.​ Mucus – secreted to form a protective layer that prevents the acid and enzymes digesting the stomach itself. Small intestine – Digestion and Absorption Final stages of digestion of lipids, carbohydrates and proteins by enzymes (that are secreted by the pancreas into the small intestine). Proteins → amino acids Carbohydrates → glucose Lipids → fatty acids and glycerol The products (amino acids, glucose, fatty acids and glycerol) are small and soluble. These are then absorbed into the bloodstream in the small intestine. The small intestine has projections known as villi, covered in microvilli. This increases the surface area and increases the rate of absorption of these molecules to the bloodstream. Large intestine - Absorption Water and ions are absorbed back into the body, leaving faeces behind. Rectum and Anus - Egestion The rectum is an elastic sack that stores the faeces until it is ready to be egested through the anus. 17. Compare and contrast the processes of chemical and mechanical digestion. Digestion is the process of breaking down LARGE INSOLUBLE nutrients into SMALL SOLUBLE nutrients that can be absorbed and used by cells. MECHANICAL DIGESTION: Physical action of breaking food down into smaller parts through the action of the teeth or churning of the stomach and intestines. CHEMICAL DIGESTION: The breaking down of large, insoluble food particles into smaller, soluble particles, mainly through the action of enzymes. This occurs in the mouth, stomach and small intestine. 18. Discuss how the adaptations of the small intestine to allow digested nutrients to be absorbed into the blood quickly. The adaptations of the small intestine that allow digested nutrients to be absorbed into the blood quickly are: · Long length – the small intestine is around 3-5 metres long. This means there is a large surface area over which nutrients can be absorbed. · Villi – These provide a large surface area to volume ratio. The villi are only one cell thick, so there is only a short distance required for nutrients to diffuse into the bloodstream. · Capillary network - There is also a large network of blood capillaries inside each villus. This increases the amount of dissolved, digested food that can be absorbed into the bloodstream from the small intestine. · Microvilli – Small finger like projections on the cells that make up the villi. These also increase the surface area over which digested nutrients can be absorbed. 19. Discuss how the respiratory system and circulatory system work together to carry out respiration Oxygen from the air we breathe in, moves via the respiratory system and gas exchange (from the trachea / bronchi / bronchioles to the alveoli) into the bloodstream in the capillaries surrounding the alveoli. Within the circulatory system red blood cells (or pulmonary vein) carry the oxygenated blood (to the heart which then pumps the blood) to the rest of the body. Oxygen then moves from red blood cell (or capillaries) into body cells where respiration breaks down glucose in the presence of oxygen to make energy. 20. Explain the role of respiration and its importance in releasing energy required for the other life processes eg: growth, reproduction Respiration is the chemical process of converting glucose and oxygen into carbon dioxide, water and energy. This energy is then used by the human body for various purposes, including growth and development. Working with the reproductive system, the energy from respiration is needed for cell division when growing a new life. The energy is also needed for growth and repair of cells (mitosis) throughout our entire lives. Another reason why we need energy for these processes, is because they use something called active transport. This process requires energy in the form of ATP. Without ATP, all other life processes such as those above could not occur. If ATP was not produced constantly through respiration, we would not be able to communicate with other parts of our body- a very dangerous possibility. The below core notes cover the Immunity Learning Objectives that will NOT be taught or assessed in 2024 as they were covered in Year 9, 2023. 13. Explain the role of the immune system The immune system is a complex network of cells and proteins that defends the body against pathogens. If the immune system is not able to defend itself against pathogens, microbes would flourish in the body, leading to death. 14. Define pathogen and give examples of pathogens A disease causing microorganism eg measles, tetanus, influenza Bacterium examples: E-Coli, salmonella, strep throat. Virus examples: Covid-19, cold, flu, measles, mumps, chicken pox Other microorganisms ie: parasites: ringworm, mites, threadworm, lice 15. Explain the role of the three levels of defence and how they work together to protect the body against pathogens The immune system includes three lines of defense against foreign invaders: physical and chemical barriers, inflammatory responses, and specific immunity. 1.​ The first line of defence (or outside defence system) includes physical and chemical barriers that are always ready and prepared to defend the body from infection. ​ The physical barrier of the skin STOPS pathogens from entering the body ​ Chemical defenses help to remove or kill pathogens in the bodies openings eg: mucus and cilia work together in the trachea to catch dust and bacteria and the mucus is then removed eg: tears; tears contain a substance called lysozyme, which has an antibacterial action, and works to prevent invasion and infection by microbes eg: stomach acid kills most microbes that are swallowed with food eg: ear wax catches dirt and bacteria which is them removed from the ear canal 2.​ The second line of defence is inflammatory responses and involves non-specific white blood cells (phagocytes), inflammatory response and fever White blood cells are a crucial phenomenon of the innate immune system that utilises a special type of immune cell called phagocytes. Phagocytes recognise and bind to pathogens and then use the plasma membrane to surround and engulf pathogens inside the cell. The digestive enzymes present inside the cell finally destroy pathogens by breaking them into fragments. Inflammation: Proteins called histamines are activated, which in turn recruit more white blood cells at the site of infection, leading to an inflammatory response (swelling, redness, pain) to clean up the wound. Fever: Fever helps to combat infection by reducing the growth rate of pathogens and increases metabolic activity of body cells. Up to a certain point fever may be beneficial, but beyond a tolerable limit it can cause damage to the body's own cells 3.​ The third line of defense is a specific immune response. An antigen is a substance that the body recognises as foreign and can cause an immune response. White blood cells can recognise an antigen introduced into the body during a prior infection or vaccination. WBC mount a rapid and strong immune response by producing antibodies when exposed to an antigen for a second time meaning you don’t get so ill the second time around. Antibodies: The adaptive immune response functions by producing proteins called antibodies which are each specific to a particular antigen. 16. Explain passive immunity (natural and artificial) Passive Immunity is the short-term immunity which results from the introduction of antibodies from another person or animal. In passive immunity, your body does not actively produce any antibodies or immune cells. Passive immunity may be acquired by a foetus through its mother’s blood. It may also be acquired by an infant through the mother’s breast milk. Another way a person can acquire passive immunity is through medical injections of antibodies. This might have to be done if someone has an autoimmune disease or for someone who has very low immunity against a pathogen. 17. Explain active immunity (natural and acquired) Active Immunity is the immunity which results from the production of antibodies by the immune system in response to the presence of an pathogen. A person can gain active immunity after they have been exposed to a live pathogen (or developed the disease). They will then develop antibodies in response to their infection. Another way a person may gain active immunity is when they are given a vaccine that contains a part of the pathogen. This stimulates an immune response and allows the person to make antibodies, without developing the disease. 18. Discuss the importance of herd immunity A form of indirect protection from disease when a large proportion of the population becomes immune to that disease. Herd immunity relies on the majority of the population being vaccinated against a disease. If herd immunity is done well, then it can be a very good form of protection for people who are immunocompromised or cannot have vaccines such as young babies who are not old enough to be vaccinated, elderly people, and people with weakened immune systems (e.g. people on chemotherapy treatment)..