Sensations & Responses.

• Interneurons are located within the CNS and connect sensory and motor neurons.
• The spinal cord is the main pathway between the brain and body.
• The autonomic nervous system (ANS) is responsible for controlling involuntary actions such as heart rate, digestion, breathing, and blood pressure.
• Synapses are junctions between two nerve cells where communication occurs through neurotransmitters.
• The ANS has two divisions: sympathetic and parasympathetic.
• Sympathetic division prepares the body to respond to stressful situations by increasing heart rate, dilating pupils, constricting airways, and releasing adrenaline from the adrenal glands.
• Neurotransmitters are chemicals that transmit signals across synapses to other neurons or target organs.
• Parasympathetic division restores homeostasis when there is no threat or danger.
• Neurotransmitters are chemicals that transmit signals across synapses.
• Neuron's parts are Dendrite, Dendron, Axon, Axonite, Schwann cell and synaptic knob.
• Dendrite receives the Impulse from the adjacent neuron.
• Dendrons carries Impulse from Dendrite to the cell body.
• Schwann cell encircles the axon.
• Axon carries Impulse from the cell body to outside the body.
• Axonite carries Impulse to the Synaptic knob.
• Synaptic knob secretes transmitters.
• Myelin sheath on the brain & Spinal cord are made of special cells is called Oligodendrocytes.
• White matter are myelinate nerve cells of the brain and spinal cord.
• Grey matter are the non-myelinated nerve cells.
• Myelin sheath?

  • Provides nutrients & oxygen to axon.
  • Accelerates Impulse
  • Acts as an electric insulator for axon.
• Synapes?


  The junction between two neurons or a neuron & a cell.
• Sensory neutron carries Impulse to the brain & Spinal cord.
• Reflex arc is a simple pathway that allows rapid response without conscious thought.
• Motor neutron carries Impulse from the Brain & Spinal cord to the other body parts.
• Nerve's axons are covered by connective tissue.
• Sensory nerve cells carry Impulse ----> Brain & Spinal cord
• Motor nerve cells carry impulses-----> the muscles.
• Mixed nerve cells carry Impulse, The muscles <------> The Brain & Spinal chord.
• The two types of Nervous System are the Central Nervous System and the Peripheral Nervous System.
• Brain is protected by, meninges, a 3 layer membrane.
• Brain's part?

  Cerebrum, Thalamus, Cerebellum, Medulla Oblongata and Hypothalamus.
• Cerebrum?


  Make involuntary movements,

  Centre of thoughts and intelligence etc,

  Largest part of Brain,

  Grey colored Cerebrum,

  White colored Medulla.

  Evokes sensations.
• Cerebellum?


  2nd largest part,

  Part of the brain responsible for motor coordination and balance,

  Seen behind the Cerebrum.
• Thalamus?


  Analyses Impulses from various parts of the body and sends an important one to Cerebrum,

  Acts a relay station of impulses to and from Cerebrum,

  Seen below Cerebrum.
• Medulla oblongata?


  Controls involuntary movements,

  Seen below Cerebrum.
• Hypothalamus?


  Maintenance of Homeostasis,

  Seen below Thalamus.