Mod 8: Non-infectious Diseases

• Homeostasis is the state of maintaining a constant internal environment using nerves and hormones, examples include pH, temperature, blood glucose, water, and salt concentration
• The hypothalamus coordinates most of the process of homeostasis and controls the nervous and endocrine systems
• Stimulus-Response Model: the body recognizes a change in the internal environment and acts accordingly to the change
• Stimulus is an action that causes a change
• Receptors are highly specialised cells that recognize the change and send messages through nerves, examples include thermoreceptors, pain receptors, photoreceptors, mechanoreceptors, and chemoreceptors
• The Control Centre relays the message to an effector, usually the brain, with the hypothalamus associated with temperature changes, relaying messages through nerves and hormones
• Effectors, which are muscles or glands, fix the imbalance by responding to the signal
• Response restores the body to its original state
• Negative Feedback Loop: information produced causes a reversal of the stimulus, examples include sweating, vasodilation of blood vessels, seeking shade for a rise in body temperature, and shivering, vasoconstriction of blood vessels, goosebumps for a drop in body temperature
• Positive Feedback Loop enhances the stimulus, examples include childbirth and urination
• Glycogen is the polysaccharide form of glucose stored in the liver and skeletal muscle cells, broken down by enzymes to release glucose monomers
• Glucagon is a peptide hormone released by alpha cells to increase blood glucose levels
• Insulin is a peptide hormone released by beta cells to decrease blood glucose levels, traveling to liver, fat, and muscle cells
• Thermoregulation is the internal regulation of an animal’s internal body temperature
• Endotherms are warm blooded animals that maintain a constant internal temperature by changing processes of the body
• Ectotherms are cold blooded animals that retain heat by using surrounding sources
• Behavioural trends and patterns in thermoregulation include:

  • Movement to shaded areas to regulate heat exposure
  • Muscle contractions producing metabolic heat
  • Sunbaking to increase surface area for heat absorption
  • Licking to evaporate more heat through saliva
  • Drinking water to replenish fluids and maintain cells in a consistent, isotonic state
• Structural trends and patterns in thermoregulation include:

  • Insulation to trap a layer of air next to the skin, reducing heat transfer
  • SA:V ratio affecting heat exchange efficiency
• Physiological trends and patterns in thermoregulation include:

  • Vasoconstriction/Vasodilation to regulate the SA:V ratio of the circulatory system
  • Metabolic rates increasing for the production of heat energy and decreasing to cool the body temperature
  • Shivering as muscle contractions produce heat energy
  • Sweating for evaporation from the skin's surface
  • Panting allowing evaporation from internal body surfaces like nasal passages, mouth, and lungs
• Hormones are chemical messengers that travel through the bloodstream to targeted tissues, affecting the metabolism of target cells by increasing or decreasing their level of activity
• Neural pathways include the Central Nervous System (CNS) consisting of the brain and spinal cord, and the Peripheral Nervous System (PNS) comprising nerves branching from the CNS to the body
• Osmoregulation in plants involves water flowing out through stomata, entering through root hair cells, and leaving through transpiration and adhesion
• Different plant adaptations for water environments:

  • Xerophytes adapted to dry environments
  • Mesophytes adapted to moderately wet environments
  • Hydrophytes adapted to wet environments
  • Halophytes adapted to saline environments
• Non-infectious diseases are not caused by pathogens and cannot be transmitted between people
• Genetic disorders are rare conditions resulting from mutations passed on from parents, ranging from minor to fatal, such as Cystic Fibrosis, Down Syndrome, and Huntington's disease
• Environmental factors like poor lifestyle choices can increase the risk of genetic mutations, for example, smoking and UV radiation
• Cancer is characterized by abnormal cell growth triggered by genetic mutations due to carcinogens, leading to rapid cell division and growth
• Nutritional disorders like Type 2 Diabetes result from an imbalance of nutrients due to underconsumption or overconsumption of food
• Type 2 Diabetes is a condition where the body becomes resistant to insulin and is unable to produce it, resulting in a build-up of glucose in the blood, influenced by genetic factors, sedentary lifestyle, and an unhealthy diet
• Melanoma is the most lethal type of skin cancer caused by UV ray exposure, genetic factors, and melanin levels, with high incidence and mortality rates
• Substrates

  Molecules which go into enzymes
• Disease


  Disturbance in normal structure and function caused by something outside the body
• Enzymes will become denatured if the temperature or pH changes outside of its optimal range
• Incidence


  How many new cases of this disease in a given time
• Mortality


  Number of deaths in a given time or location
• Substrates

  Molecules part of a chemical reaction which react together to form the products
• Hormones


  Chemicals which are used to control organs in the body
• Prevalence


  How many people have had this disease in a given time
• Enzymes

  A protein that is responsible for lowering the activation energy of a reaction, making it occur faster
• Disorder


  Disturbance in normal body structure and function caused by something inside the body