Bio 2

• Homeostasis


  The regulation of internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes
• Homeostasis


  • Carried out through automatic control systems
  • Ensures the body's internal conditions stay as conducive as possible
• Homeostasis system


  1. Sensors detect change in environment

  2. Coordination centre receives and processes information

  3. Effectors carry out response
• Coordination centre


  The brain, spinal cord, and other organs that receive and process information
• Effectors


  • Muscles, glands
• Homeostasis is the regulation of internal conditions to maintain optimum and stable conditions
• Homeostasis is carried out through automatic control systems
• Homeostasis ensures the body's internal conditions stay as conducive as possible
• Homeostasis systems involve sensors detecting changes in the environment, a coordination centre receiving and processing the information, and effectors carrying out the response
• The coordination centre includes the brain, spinal cord, and other organs
• Effectors include muscles and glands
• Nervous System


  Consists of central nervous system (CNS) and peripheral nervous system (PNS)
• Sensory neurons


  1. Receive stimuli

  2. Send electrical impulses down to CNS
• Neurotransmitters


  Chemical released at synapses to transmit signals between neurons
• Practical Reaction Time experiment
• Reaction Time Experiment


  1. Person A holds hand with gap

  2. Person B holds ruler

  3. Person A drops ruler

  4. Person B must catch it
• Repeat the reaction time experiment 10 times and swap places
• Dependent Variable (DV)


  Reaction time
• Controlled Variable (CV)


  Starting distance
• Endocrine System


  Consists of glands that secrete hormones (chemical messengers) into the bloodstream
• Hormones


  Act slowly around the body, have long-lasting effects
• Hormones are secreted directly into the bloodstream
• Pancreas


  Releases hormones, controls concentration & flow
• Ovaries


  Release hormones
• Thyroid


  Produces hormones, regulates growth
• Hormones


  Control body's reactions, produced in glands
• Pituitary gland


  Located in brain, master gland that releases different hormones, acts on other glands
• Carbohydrate metabolism


  1. Pancreas releases insulin to store excess glucose in liver and muscles

  2. Pancreas releases glucagon to break down stored glucose and release it into blood when concentration is low
• Blood glucose concentration


  Controlled by insulin and glucagon from pancreas
• Testosterone


  Hormone produced by testes, stimulates sperm production
• Estrogen


  Hormone produced by ovaries
• Menstrual cycle


  1. Pituitary gland releases FSH to stimulate egg maturation in ovaries

  2. Ovaries release estrogen and progesterone

  3. Progesterone prepares uterus lining for implantation

  4. If egg not fertilized, uterus lining is shed (menstruation)
• Contraception


  • Hormonal methods (pill, implant, injection) contain hormones to prevent ovulation and pregnancy
  • Barrier methods (condom, diaphragm) physically prevent sperm from reaching egg
• Infertility treatment


  Provide FSH and LH hormones to stimulate egg maturation, collect sperm, and assist fertilization in laboratory
• Negative feedback


  Brain monitors chemical levels and adjusts hormone production to maintain homeostasis
• Gametes


  Made by meiosis
• Meiosis produces non-identical cells
• Types of reproduction


  • Sexual
  • Asexual
• Sexual reproduction


  Involves male and female gametes
• Asexual reproduction


  Involves one parent