parts of the nervous system chapter 12

Outline of Nervous System and Brain

1. Overview of the Nervous System

• Parts: Brain, Central Nervous System, Cranial Nerves, Glands, Muscles, Nerves, Peripheral Nervous System, Sensory Receptors, Spinal Cord, Spinal Nerves.

2. Nervous Tissue

• Neurons:

  • Parts: Axon, Nerve Cell Body, Dendrites.

  • Dendrites receive impulses; one axon creates nerve impulses.

• Myelin: Fatty insulation for neurons.

• Types of Cells: Neurons and Neuroglial Cells.

• Synapse: Junction between dendrite and another neuron; synaptic cleft is the space where electrical impulses do not pass.

• Neurotransmitters: Chemical messengers carrying signals for electrical impulses.

3. Central Nervous System

• Composed of white and grey matter:

  • Grey Matter: Unsheathd cells and dendrites.

  • White Matter: Myelinated nerve fibers, appearing white.

• Connective fibers: Tracts.

• Protection: Meninges (3 membranes).

4. Meninges

• Three protective connective tissue layers surrounding the brain and spinal cord:

  • Dura Mater

  • Arachnoid Layer

  • Pia Mater

  • Spaces: Subdural space and subarachnoid space.

5. Brain

• Largest organ; controls all other organs and bodily functions.

• Sections:

  • Cerebrum

  • Cerebellum

  • Diencephalon

  • Brain Stem

• Key Structures: Pituitary Gland, Cerebral Cortex, Gyri, Sulci, Thalamus, Hypothalamus.

• Functional Lobes:

  • Frontal Lobe: Motor function, personality, speech.

  • Parietal Lobe: Language, interpretation.

  • Occipital Lobe: Vision.

  • Temporal Lobe: Hearing, smell.

• The thalamus: Grey matter; processes special senses.

• The hypothalamus: Manages sleep, emotions, body temperature, appetite, and autonomic nervous system.

6. Spinal Cord

• Components: Ascending tracts, Descending tracts, Central canal.

• Pathway for impulses to/from the brain.

• Composed of 33 vertebrae; ends at the second lumbar vertebra.

Peripheral Nervous System

afferent neurons carry sensory information from sensory receptors to the brain. A good way to remember this is Afferent for Away from sensory receptors. afferent Neurons are also called sensory nuerons

efferent Neurons are also called motor Neurons. They send signals from the brain to the rest of the body.

ganglion is the term for all of the nervous tissue as a whole

the Nerves of the Peripheral nervoys system are subdivided into two parts. They are the autonomic nervous system and somatic nerves.

Autonomic Nervous System

Parasympathetic branch: controls rest and digest

sympathetic branch: controls fight or flight

these two branches have opposite functions in order to balance each other out

Somatic Nerves

Nerves that serves the skin and skeletal muscles. This system controls voluntary movement

sensory receptor cells of the somatic nervous system also control things like temperature, pressure, and pain.