Central, Peripheral, and Autonomic Nervous Systems

Overview

• The nervous system coordinates and controls the human body's operations.
• Divided into three subsystems:
  1. Central or cerebrospinal nervous system (CNS)
  2. Peripheral nervous system (PNS)
  3. Autonomic nervous system (ANS)
• Primary components: brain, spinal cord, nerves.

Central Nervous System (CNS)

• Composed of the brain, spinal cord, spinal and cranial nerves.
• Responsible for voluntary body actions.
• Brain: the command center, weighs 45-49 ounces.
• Spinal cord: long nerve fibers, 31 pairs of spinal nerves extending to muscles, organs, skin.

Peripheral Nervous System (PNS)

• Composed of sensory and motor nerves connecting CNS to the body.
• Nerve cells (neurons): nucleus, cytoplasm, membrane, axons (away from cell), dendrites (to the cell).
• Reflex actions: sensory and motor nerves interacting.

Autonomic Nervous System (ANS)

• Responsible for involuntary body functions.
• Operates the digestive, excretory, respiratory, circulatory, endocrine, and reproductive systems.

Detailed Nervous System Components

Cranial Nerves

• 12 pairs, key for facial control: trifacial (5th cranial) and facial (7th cranial) nerves.
• Trifacial nerve: sensory, motor functions, divides into branches (ophthalmic, maxillary, mandibular).
• Facial nerve: controls facial expressions, key branches (posterior auricular, temporal, zygomatic, bucal, marginal mandibular, cervical).

Arm and Hand Nerves

• Ulnar, radial, median, digital nerves transmit and receive impulses between brain and muscles.

Leg and Foot Nerves

• Sciatic, tibial, common peroneal, deep and superficial peroneal, dorsal, saphenous, sural nerves assist in movement and balance.

Other Body Systems Interacting with ANS

Digestive System

• Enzymes begin breaking down food in mouth.
• Stomach acids and enzymes further break down food.
• Small intestine absorbs nutrients.
• Large intestine stores waste for elimination.

Excretory System

• Eliminates waste through skin, liver, kidneys.
• Kidneys filter blood, excrete waste through urine.

Respiratory System

• Intake of oxygen, expulsion of carbon dioxide.
• Key organs: lungs, diaphragm.

Endocrine System

• Ductless glands secrete hormones.
• Regulates growth, reproduction, health.
• Affects hair growth, skin conditions, energy levels.

Reproductive System

• Responsible for procreation.
• Hormones influence skin, hair growth and color.

Learning Validation

• "Check What You Know" questions affirm understanding.
• Celebrate learning achievements in final slides.