Biology Chapter on Coordination and Systems

Coordination

• Organisms need to detect and respond to changes in their internal and external environments.
• Coordination helps all parts of the body work together.
• Stimulus: Anything sensed by a neuron is called a stimulus.
• Nervous System: Electrical messages (impulses) sent quickly via nerves.
• Endocrine System: Chemical messages called hormones travel slowly via bloodstream.

Nervous System

• Controls & coordinates all parts of the body.
• Central Nervous System (CNS): Brain and spinal cord.
• Peripheral Nervous System (PNS): Network of nerves that connect the CNS to the rest of the body.

Vertebrate Sensory Receptors

• Detect changes in the environment.

Endocrine System and Hormones

• Consists of glands that produce hormones.
• Hormones: Chemicals that transfer information around the body.
• Hormones control changes in our bodies, like growth and development, water balance, and sexual reproduction.

Diseases

• Can be classified based on their causes.
• Infectious diseases: Caused by pathogens and can be transmitted.
  • Examples: influenza, tuberculosis, tinea.
  • Pathogens include bacteria, fungi, viruses, and parasites.
• Non-infectious diseases: Cannot be transmitted.
  • Genetic: Cystic fibrosis.
  • Nutritional: Heart disease.
  • Environmental: Lung cancer.
  • Physiological malfunction: Shortsightedness.

Atoms and Elements

• Microscopic particles that make up all matter.
• Composed of protons (p+), neutrons (n), and electrons (e-).
• In a neutral atom: Atomic number = number of protons = number of electrons.
• Mass number: Total number of protons and neutrons in the nucleus.

Structure of the Periodic Table

• There are about 118 elements, 92 naturally occurring.
• Arranged by atomic number (number of protons).
• Reactivity:
  • Most reactive elements are on the left side.
  • Transition metals in the center.
  • Least reactive elements are on the right side.

Radioactivity

• Most nuclei are stable, but some are unstable and spontaneously decay, emitting radiation.
• Neutrons play a key role in stabilizing the nucleus.
• Nuclei with too many or too few neutrons tend to decay.

Chemical Reactions

• When atoms react to form compounds, it's the electrons in the outer shell that determine the type of reaction.
• Example: Sodium + chlorine = sodium chloride (Na + Cl = NaCl)