B2: Nervous System

Cards (41)

  • Components of the nervous system include:
    • Brain
    • Spinal cord
    • Sensory and motor neurones:
    • Dendrites, cell body, nucleus, axon, myelin sheath of Schwann cells, nodes of Ranvier, axon endings/terminals, and synaptic ends
    • Relay neurones
    • Synapses
  • Sensory neurones carry impulses from receptors to the central nervous system (CNS)
  • Motor neurones carry impulses away from the CNS to effectors
  • The CNS is made up of the brain and spinal cord, it controls the regulation of body systems
  • the PNS is made up of all the neurons connecting the CNS to the rest of the body, the PNS sends messages from the body eg. foot on pin, to the spinal cord and/or brain and back
  • Involuntary muscle actions are automatic eg. thoughts, feelings, memories, heartbeat, blood pressure
  • Voluntary muscle actions are conscious such as walking and waving
  • neurons = brain and nervous system cells
  • receptors take the info from the sensory neurons to the cns and brain
  • motor neurons send messages from the CNS and brain to the effectors
  • interneurons are in-between - they connect spinal motor and sensory neurons
  • Dendrites receive the message from the neuron that carries the message prior to reaching the second neuron
  • the nucleus guides the axon hillock that generates the impulses throughout the axon
  • the cell body has genetic information, maintains the neurons structure and provides energy
  • the axon is where electrical impulses from the neuron travel away to be received by other neurons
  • myelin sheath is an insulating layer of lipids which allows electrical impulses to transmit quickly and efficiently along the nerve cells
  • nodes of ranvier are microscopic gaps found within myelinated axons. their function is to speed up the impulse
  • Schwann cells have a role in the maintenance and regeneration of axons of the neurons
  • axon terminals is where the electrical impulse travels and leaves to get to the next neurons dendrites
  • when the messages reach the feet of the axon (axon terminals), the nerve impulse has to cross a gap so it can reach the dendrite of the next cell, this is known as the synaptic gap
  • electrical impulses travel down the axon and reach the end of the axon terminals. they reach the synaptic gap and are then converted into a chemical message to jump the gap and then reverts back to an electrical impulse when it reaches the dendrite
  • Motor neuron: long axon, no receptor, has a cell body terminal and dendrites, many short dendrons
  • Sensory neuron: short axon, receptor, cell body at the side and no dendrites, one long dendron
  • the somatic nervous system consists of nerves that go to the skin and muscles and is involved in conscious activities eg. touching your nose
  • the autonomic nervous system consists of nerves that connect the CNS to the visceral organs and is responsible for unconscious activities
  • visceral organs = heart, stomach and intestines
  • A reflex arc is the pathway that a reflex takes in the body. touching something hot (stimulus) -> impulse through sensory neuron -> to relay neuron in spinal cord -> impulse through motor neuron to muscle -> muscle (effector) in the arm moves away from flame
  • the cerebellum coordinates the body's movements
  • the medulla is where your brain and spinal cord connect, making it a key channel for nerve signals to and from your body, it controls vital processes such as heart beat and blood pressurw
  • parasympathetic ns = relaxed
  • sympathetic ns = alert/fight
  • Parkinsons is caused by a loss of nerve cells in part of the brain called the substantial nigra. This leads to a reduction in dopamine in the brain.
  • Parkinsons symptoms : tremor, slow movement, stiff and inflexible muscles
  • Deep Brain Stimulation is a type of surgery that is used to treat Parkinson's. It is an ongoing treatment not a one off. It implants electrodes and electrical stimulation to reduce symptoms.
  • Receptors: ​Organs or cells that detect stimuli.
  • Reflex action: ​A rapid and automatic response to a stimulus.
  • Stimuli: ​Changes in the environment.
  • The central nervous system (CNS): ​The brain and spinal cord which coordinate the response of effectors.
  • Thyroxine: A hormone produced by the thyroid gland that increases the metabolic rate in the body.
  • Somatic nervous system

    One of two main divisions of the peripheral nervous system; responsible for transmitting sensory information from the skin and muscles to the brain and spinal cord, and for controlling voluntary movements of the muscles