Nervous System Worksheet illustrating the structure and function of the human nervous system.

Let's solve the Nervous System Worksheet step by step. The goal is to fill in the boxes and indicate the function of each component of the human nervous system based on the diagram provided.

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🔹 Step 1: Understand the Structure

The nervous system is divided into two main parts:

1. Central Nervous System (CNS)
2. Peripheral Nervous System (PNS)

Each of these branches further into subparts.

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✔ Fill in the Boxes with Functions

We'll go through each box one by one, starting from the top and moving down.

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#### 🟦 Top Level: Nervous System

- Central Nervous System (CNS)
→ Function: Integrates sensory information and coordinates responses. It processes information and sends commands to the body.

- Peripheral Nervous System (PNS)
→ Function: Connects the CNS to the rest of the body. Transmits sensory input to the CNS and motor output from the CNS to muscles and glands.

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#### 🟦 CNS Branches

1. Brain
→ Function: Controls higher functions such as thought, memory, emotion, sensory processing, and voluntary movement. It is the center for decision-making and coordination.

2. Spinal Cord
→ Function: Acts as a pathway for signals between the brain and the body. Also controls reflex actions independently of the brain (e.g., knee-jerk reflex).

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#### 🟦 PNS Branches

1. Somatic Nervous System
→ Function: Controls voluntary movements of skeletal muscles. Carries motor commands from the CNS to the muscles.

2. Autonomic Nervous System (ANS)
→ Function: Regulates involuntary bodily functions such as heart rate, digestion, respiration, and glandular activity.

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#### 🟦 Subdivisions of Autonomic Nervous System

1. Sympathetic Division
→ Function: Prepares the body for "fight or flight" responses during stress. Increases heart rate, dilates pupils, inhibits digestion.

2. Parasympathetic Division
→ Function: Promotes "rest and digest" activities. Slows heart rate, stimulates digestion, promotes relaxation.

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#### 🟦 Neuron Types (under Somatic Nervous System)

1. Sensory (Afferent) Neurons
→ Function: Carry sensory information from sensory receptors (e.g., skin, eyes) to the CNS. They transmit data about external and internal stimuli.

2. Motor (Efferent) Neurons
→ Function: Carry signals from the CNS to muscles and glands, causing them to respond (e.g., muscle contraction, secretion).

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✔ Final Answer: Filled-in Worksheet

Here’s how the completed worksheet should look:

```
NERVOUS SYSTEM
/ \
Central Nervous System Peripheral Nervous System
/ \ / \
Brain Spinal cord Somatic Nervous System Autonomic Nervous System
| | | |
Controls thought, Coordinates Controls voluntary Regulates involuntary
memory, emotion, reflexes, movements of skeletal functions (heart,
sensory processing signal relay muscles digestion, etc.)
|
|
Sensory (afferent) neurons Motor (efferent) neurons
↑ ↑
Carry sensory info to CNS Carry motor commands to muscles/glands

Autonomic Nervous System
/ \
Sympathetic Division Parasympathetic Division
"Fight or flight" "Rest and digest"
(increases HR, dilates pupils) (slows HR, stimulates digestion)
```

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📌 Summary Table (for clarity):

| Component | Function |
|---------|--------|
| Central Nervous System (CNS) | Integrates information and coordinates responses |
| Peripheral Nervous System (PNS) | Connects CNS to body; transmits signals |
| Brain | Controls cognition, emotions, voluntary movement |
| Spinal Cord | Relay station and site of reflexes |
| Somatic Nervous System | Controls voluntary movements |
| Autonomic Nervous System | Controls involuntary functions |
| Sympathetic Division | Activates stress response ("fight or flight") |
| Parasympathetic Division | Promotes relaxation and digestion ("rest and digest") |
| Sensory (Afferent) Neurons | Transmit sensory input to CNS |
| Motor (Efferent) Neurons | Transmit motor commands from CNS to effectors |

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✔ This completes the worksheet! Each box has been filled with the correct function based on anatomical and physiological knowledge of the human nervous system.