Which of the following is true for human neural system?

Options

A. (1) it is ectodermal in origin
B. (2) somatic neural system relays impulse from CNS to skeletal muscle
C. (3) neurons show unidirectional conduction of impulse
D. all of these

Answer

To determine which statements are true regarding the human neural system, we will analyze each option provided in the question step by step.

### Step-by-Step Solution:

1. **Understanding the Origin of the Nervous System**:
- The human nervous system originates from the ectoderm. This is a fundamental concept in embryology where the ectoderm is one of the three primary germ layers formed during embryonic development.
- The development of the nervous system is influenced by inductive signals from the mesoderm, which plays a crucial role in the formation of the notochord.

**Hint**: Remember that the nervous system is derived from the ectoderm and is influenced by the mesoderm.

2. **Formation of Neural Structures**:
- The ectoderm differentiates into neural ectoderm, which gives rise to the neural tube and neural crest.
- The neural tube eventually develops into the brain and spinal cord, while the neural crest contributes to the formation of peripheral nerves.

**Hint**: Neural ectoderm leads to the formation of critical structures like the brain and spinal cord.

3. **Somatic Nervous System Function**:
- The somatic nervous system is responsible for relaying impulses from the central nervous system (CNS) to skeletal muscles. This system controls voluntary movements.
- In contrast, the autonomic nervous system transmits impulses to involuntary organs and smooth muscles.

**Hint**: The somatic nervous system is linked to voluntary control, while the autonomic nervous system manages involuntary functions.

4. **Direction of Impulse Conduction in Neurons**:
- Neurons conduct impulses in a unidirectional manner. This means that the action potential travels from the dendrites through the axon to the axon terminals.
- This unidirectional flow is due to the structure of the neuron and the way action potentials are generated and propagated.

**Hint**: Neurons transmit signals in one direction, from input (dendrites) to output (axon terminals).

5. **Conclusion**:
- After analyzing all the statements, we find that:
- The first statement about the ectodermal origin is true.
- The second statement regarding the somatic nervous system is also true.
- The third statement about unidirectional conduction of impulses in neurons is true as well.
- Therefore, all three options provided are true.

### Final Answer:
All three statements about the human neural system are true.