Bio p2

• Homeostasis is the regulation of a constant internal environment to ensure optimum conditions for metabolism and changes in response to both internal and external fluctuations
• In humans, homeostasis regulates:

  • Body temperature
  • CO₂ levels
  • Water levels
  • Glucose (sugar) levels
• Levels in homeostasis are monitored and regulated by automatic control systems which can involve nervous responses or chemical responses
• Information about the environment stimulus is detected by a receptor, which are proteins in or on the surface that detect a signal
• Synapses are the gaps where the ends of two neurons meet, and the information is passed from one neuron to the next through chemical neurotransmitters
• The human nervous system allows a fast, short-lived response to a stimulus in the surroundings
• Information is received by a receptor, passed along neurons (nerve cells) as an electrical impulse, and results in a response
• Sensory neurons have dendrites, cell bodies, and axons surrounded by a myelin sheath
• Some axons have a myelin sheath, which helps the electrical impulse travel faster
• The branched endings, dendrites, connect the neurons together to create a network
• The axon is the main part of the nerve cell, a long stretched-out fiber of cytoplasm along which the electrical impulse will travel
• Hormones are chemical messengers transported in the bloodstream to an effector where they can activate a response
• Hormones are produced and released from glands around the body, making up the endocrine system
• Hormones do a similar job to the nervous system but there are some differences
• Hormones are chemical messengers that regulate various physiological processes such as growth, metabolism, reproduction, and homeostasis.
• The main function of the endocrine system is to secrete hormones into the bloodstream, which then travel throughout the body.