Biology HS

• Filtration


  1. Blood plasma is filtered into the capsule = glomerular filtration (approximately 180 l/day)

  2. Waste products as well as useful substances for the body are filtered into the capsule

  3. Blood cells and large-molecule proteins are not filtered
• Reabsorption


  1. Water and useful substances for the body, such as glucose, amino acids, lipids, as well as sodium and potassium ions, are reabsorbed into blood

  2. Lipophilic environmental toxins and alcohol are reabsorbed into blood

  3. Around 99 % of glomerular filtration is reabsorbed into circulation
• Secretion


  1. Substances, such as hormones, drug substances and food additives pass on to renal tubules through secretion

  2. Secreted substances exit the body with urine
• Contents of urine


  • Water (around 95 %)
  • Urea
  • Other nitrogenous substances (creatine, uric acid and ammonium)
  • Salts (sodium and potassium ions)
  • Glucose (diabetes)
  • Hormones
  • Bacteria
  • White blood cells
  • Medicine
  • Narcotics
• Hypothalamus and ADH regulation

  1. Hypothalamus registers changes in blood concentration

  2. When the concentration of water in blood is small, the pituitary gland secretes antidiuretic hormone (ADH) that decreases urine secretion

  3. A small amount of urine exits the body (the concentration of water in urine is small)

  4. The hypothalamus thirst centre causes the sense of thirst

  5. As blood water concentration increases, the secretion of ADH decreases

  6. The kidneys secrete a large amount of diluted urine
• Voluntary muscles


  • Together with bones, joints and the nervous system, are responsible for body movements
  • Protect internal organs
  • Function as energy reserves (ATP, phosphocreatin and glycogen)
  • Participate in thermoregulation
• Involuntary muscles


  • Protect internal organs
  • Execute, for example, the movements of the digestive tract
• Cardiac muscle


  • Pumps blood into organs
• Bones


  • Make up a skeleton that muscles are attached to
  • Protect internal organs
  • Produce blood cells
  • Function as reserves for minerals, such as calcium
  • Together with muscles, dictate the visible form of the body
• Muscle contraction


  1. Axon transmits a nerve impulse to a motor neuron synapse

  2. Releasing of calcium ions activates muscle contraction

  3. Neurotransmitter enters the synaptic cleft and sodium channels open

  4. Actin and myosin proteins slide past each other during muscle contraction, and the muscle cell contracts

  5. A muscle cell always contracts by an "all or nothing" principle

  6. The more individual muscle cells contract, the stronger is the muscle contraction
• Naturally occurring greenhouse effect

  The process where troposphere greenhouse gases bind thermal radiation, making global temperature ideal for life
• Climate change


  Human caused increase of greenhouse gases, which increases the global mean temperature
• Sources of greenhouse gases

  • Burning of fossil fuels
  • Rice cultivation
  • Livestock farming
  • Landfill sites
  • Tree felling (swamp drainage)
• Greenhouse gases


  • Carbon dioxide (cellular respiration, burning of organic substance, especially the burning of fossil fuels)
  • Methane (breaking of organic compounds in anaerobic environments, e.g. rice fields and livestock digestion)
  • Ozone in the troposphere (exhaust gas from cars, industry)
  • Nitrous oxide (agriculture)
  • Halogenated hydrocarbons (electronics and electricity industry)
  • Water vapour (the most significant natural greenhouse gas)
• Effects of climate change

  • Desertification
  • Changes in rainfall (floods etc.)
  • Changes in ecosystems
  • Increased length of growing season in northern areas
  • Changes in the number of species and food webs
  • Changes in animal behaviour
  • Warming of sea water (coral reefs suffer)
  • Biome movement
• Measures to reduce greenhouse gas emissions

  • Decreasing of greenhouse emissions (shifting away from fossil fuels, decreasing consumption, using renewable natural resources (replacing plastics), shifting towards using food that includes more plant-derived products)
  • Increasing carbon sinks (taking care of forest growth, wetlands)
• Mutation


  A permanent change of genetic resource that occurs in chromosomes and chromosomal complements
• Types of mutations


  • Gene mutation (point mutations, changes in the number of nucleotides)
  • Chromosome mutation (deletion, duplication, inversion, insertion, translocation)
  • Genome mutation (monosomy, trisomy, polyploidy)
• Gene Mutations

  
  

  - Cystic Fibrosis

  - Sickle cell anemia

  - Aspartylglucosaminuria (AGU)
• Fitness


  An individual's possibility to reach reproductive age and receive offspring that are capable of reproduction
• Mutation impacts genotype


  Can affect fitness, and natural selection favours phenotypes that are best adapted to each environment
• Mutation can also decrease fitness
• In plants, polyploidy often increases adaptation to extreme conditions, such as cold or dry environments
• 1. Afferent arteriole

  2. Glomerulus

  3. Capsule

  4. Renal tubule

  5. Collection duct