Year 11 Biology Homeostasis

Summary:

This note covers Year 11 Biology Homeostasis lesson. Homeostasis itself is the maintenance of a constant internal environment in an organism. Homeostasis occurs when variables in an organism are maintained within certain limits. An organism is healthy when its systems are in homeostasis, and this is achieved by feedback loops where receptors detect a change and a response is coordinated. The note discusses different types of sensory receptors that detect changes from the internal and external environment, and how the nervous system, including the central and peripheral nervous systems, plays a role in homeostasis. The note also covers metabolism, including anabolism and catabolism, and the endocrine system, which coordinates many body functions including growth, reproduction, and metabolism through the use of hormones. Lastly, the note discusses thermoregulation, osmoregulation in animals and plants, and hormonal control of water balance.

Excerpt:

Year 11 Biology Homeostasis

Homeostasis:

• Maintains a constant internal environment
• Occurs when variables in an organism are maintained within certain limits
• An organism is healthy its systems are in homeostasis
• Body Temp, water and ion, blood pH pressure, heat rate, and concentration of gases need to be maintained
• Achieved by feedback loops where receptors detect a change and
  a response is coordinated

Terms:

a. Homeostasis: Maintaining of the internal environment
b. Endocrine system: Bodies different glands and hormones
c. Neuron: Sends and receives electrical systems around the body via the nervous system
d. Hormone: A signalling molecule that detects any chemical changes in the body

Sensory receptors: Detects change from the internal ad external environment

Types
● Exteroceptors
– Detects external change (Outer body i.e skin, eye etc)
● Interoreceptors
– Detects internal change
– Within organs, blood vessels etc
● Mechanoreceptors
– Respond to mechanical pressure (stretch, touch, movement)
● Chemoreceptors
– Detect changes in blood concentrations (oxygen, CO2, pH)
– Detect specific chemicals (Blood vessel, taste, buds)
● Thermoreceptors
– Detects change in temperature
● Electroreceptors
– Detects electric currents
● Photoreceptors
– Detects light
– Interacts with pigment and produces an electrical signal which is sent to a sensory nerve
– Nociceptors
– Responds to damage stimuli (pain)