RAC Neurons

• Sensitivity


  One of the eight characteristics shared by living organisms (MRS C GREN), refers to their ability to respond to changes in the environment
• Plants and animals both increase their chance of survival by responding to changes in their surroundings
• Stimulus


  A change in the environment of an organism
• Animals respond to a stimulus in order to keep themselves in favourable conditions
• Homeostasis


  The maintenance of a constant internal environment
• Examples of homeostasis


  • Maintaining body water content
  • Maintaining body temperature
• Coordinated response


  1. Stimulus

  2. Receptor

  3. Effector
• Skin in temperature regulation


  • Sweating
  • Vasoconstriction
  • Vasodilation
• Sweat glands


  Produce sweat, water in sweat evaporates to cool the skin
• a nerve impulse travels along an axon from one end called the initial segment to the terminal button at the other end where it releases neurotransmitters into synaptic clefts between two neurones or between a neurone and an effector cell.
• a neuron consists of three parts - dendrites, cell body and axon
• neurons are specialised cells that transmit electrical impulses to carry messages around the body
• neurons are specialised cells that transmit electrical signals to communicate with other neurones or effectors such as muscles and glands.
• Neurotransmitters can have excitatory or inhibitory effects on the receiving neuron.
• Examples of neurotransmitters include dopamine, serotonin, and acetylcholine.
• Neurotransmitters are chemical messengers that transmit signals across a chemical synapse from one neuron to another.
• the nervous system is made up of the central nervous system which includes the brain and spinal cord, and the peripheral nervous system which includes all other nerves
• The central nervous system (CNS) is made up of the brain and spinal cord
• the nervous system is made up of billions of interconnected neurons which work together to control all activities within the body.
• Neurons have four main regions: dendrites, cell body, axon hillock and axon
• the nervous system is made up of billions of neurons which communicate with each other by sending electrical signals down their long extensions called axons
• Neurons have four main regions: the dendrites receive information; the cell body contains the nucleus and organelles; the axon transmits information away from the cell body; and the axon terminals release chemicals called neurotransmitters.
• The central nervous system (CNS) includes the brain and spinal cord. The peripheral nervous system (PNS) includes nerves outside the CNS.
• A reflex arc is a simple pathway through the nervous system that allows rapid responses without conscious thought.
• Neurons have three main regions; the dendrite receives information from other neurons, the cell body contains the nucleus and organelles, and the axon transmits information away from the cell body.
• The nervous system is made up of billions of neurons which are connected by synapses.
• the nervous system is made up of billions of interconnected neurons which work together to control all activities within our bodies.
• Reflex arcs involve sensory receptors, interneurons, motor neurons, and effectors.
• The somatic nervous system controls voluntary movements
• The central nervous system (CNS) is composed of the brain and spinal cord. The peripheral nervous system (PNS) includes nerves that connect the CNS to the rest of the body.
• Sensory receptors detect changes in the environment and send information to the CNS via sensory neurones
• The autonomic nervous system controls involuntary actions like heart rate and digestion
• The somatic nervous system controls voluntary movements
• The sympathetic division prepares the body for action by increasing blood pressure, breathing rate, and heart rate
• The sympathetic division prepares the body for action by increasing blood pressure, breathing rate, and heart rate
• Sensory neurones carry messages towards the CNS
• Motor neurones carry messages away from the CNS
• Sensory receptors detect changes in the environment or inside the body.
• Interneurons are found only in the CNS and connect sensory and motor neurones
• Reflex arcs allow fast reactions without involving higher centres such as the cerebrum.