Nervous system

• Nervous System


  Responds to changes in the environment and coordinates the body's responses
• Nervous System


  • Responds to stimuli
  • Maintains homeostasis
  • Coordinates with other organ systems
• Stimuli


  Various changes in the environment act as triggers for the nervous system to initiate responses
• Homeostasis


  Essential for maintaining internal balance and stability within the body
• Coordination


  The nervous system works in conjunction with other organ systems to regulate bodily functions and maintain homeostasis
• Endocrine System


  Secretes hormones that regulate various physiological processes and maintain internal balance
• Endocrine System


  Works alongside the nervous system to ensure coordination and harmony among different organ systems
• The need


  The specific and rapid eliciting a response
• Body quick response


  Due to synergistic effect of both chemical and electrochemical
• The Kingdom of Animalia has no true nervous system but they have a system of jepune but connected to nerve cells called nerve net
• Flatworms (Platyhelminthes)


  • Possess a nerve net connected to nerve cells, with bilateral symmetry
  • They have defined head and tail regions, two nerve cords, and a peripheral nervous system
• Mollusks


  • They have a small brain and possess concentrated nerve knots known as ganglia spread throughout their bodies
• Segmented Worms (Annelids, e.g., Earthworms)


  • Annelids have a more organized nervous system compared to flatworms
  • They possess a central nervous system, peripheral nervous system, and sympathetic nervous system
  • The sympathetic nervous system controls involuntary functions
• Arthropods (Insects)


  • Arthropods have a brain, ventral nerve cord, and ganglia
  • These ganglia control movement and behaviors without the need for much input from the brain
• Neurons


  The basic units of the nervous system, responsible for transmitting and receiving electrical signals
• Glial cells


  Provide structural support and various functions for neurons
• The human body contains approximately 86 billion neurons, forming intricate networks that last a lifetime
• Types of neuron


  • Sensory neuron
  • Motor neuron
  • Interneurons
• Sensory neuron


  Received information through senses
• Motor neuron


  Transmit signals from the central nervous system to muscles or glands, enabling movement or secretion
• Interneurons


  Interpret and give right action that proceed to motor neuron
• General Function of the Nervous System

  • Gather information both form the outside world and from inside the body
  • Sends information to your muscles and organs so they can responds correctly
  • Transmit information to the processing areas in the brain and spinal cord
  • Process information to determine the best response
  • Keep the body to adopt from changes to its environment
• Nerve impulses


  • Cell body
  • Detrites
  • Axon
  • Mylen
• Division of Nervous System

  • CNS (Central Nervous System)
  • PNS (Peripheral Nervous System)
• CNS (Central Nervous System)

  • Brain: Receives and processes sensory information. Protected by the skull, it contains about 100 billion neurons. The brain is covered by gray matter, rich in interneurons, while beneath it lies white matter. It weighs approximately 1.4 kg.
  • Spinal Cord: A tubular organ of neurons and blood vessels, about 1.8 cm in diameter, located within the spine. It plays a crucial role in reflexes and serves as a pathway for sensory and motor signals between the brain and the rest of the body.
• PNS (Peripheral Nervous System)

  • Motor Neurons: Transmit signals from the CNS to muscles and glands.
  • Sensory Neurons: Transmit signals from sensory organs to the CNS.
• Motor Neuron Subtypes


  • Somatic NS: Controls voluntary movements involving skeletal muscles.
  • Autonomic NS: Controls involuntary movements, such as those of smooth muscles.
• Autonomic NS Subdivisions


  • Sympathetic Division: Activated during "fight or flight" responses.
  • Parasympathetic Division: Activated during "rest and digest" responses.
• Main Parts of the Brain


  • Cerebrum
  • Cerebellum
  • Brain Stem
• Cerebrum


  The largest portion of the brain, responsible for deep thinking and cognitive functions
• Cerebellum


  Located behind the brain stem, it regulates movement, posture, and balance
• Brain Stem


  Controls essential functions such as breathing, heart rate, and reflexes, and connects the spinal cord to the rest of the brain
• Cerebral Cortex


  • The outer layer of the cerebrum, characterized by deep wrinkles that increase surface area for thinking activities
• Lobes of the Cerebrum

  • Frontal Lobe
  • Parietal Lobe
  • Temporal Lobe
  • Occipital Lobe
• Frontal Lobe


  Responsible for thinking, planning, and short-term memory
• Parietal Lobe


  Processes touch, smell, and taste sensations
• Temporal Lobe


  Involved in memory formation
• Occipital Lobe


  Processes visual information
• Brain Stem Components


  • Medulla Oblongata
  • Midbrain
  • Pons
• Medulla Oblongata


  Controls involuntary actions like heartbeat, breathing, and blood pressure