responding to the enviroment(humans)

What are the two main components of the human nervous system?

1. Central Nervous System (CNS): Consists of the brain and the spinal cord.
2. Peripheral Nervous System (PNS): Consists of cranial and spinal nerves that connect the CNS to the rest of the body.

Define a reflex arc and list its five essential components.

A reflex arc is the neural pathway that controls a reflex action. Its components are:

• Receptor: Detects the stimulus.
• Sensory Neuron: Transmits impulse to the CNS.
• Interneuron: Connects sensory and motor neurons in the CNS.
• Motor Neuron: Transmits impulse to the effector.
• Effector: The muscle or gland that carries out the response.

Distinguish between the sympathetic and parasympathetic nervous systems.

• Sympathetic Nervous System: Prepares the body for 'fight or flight' situations (e.g., increasing heart rate and dilating pupils).
• Parasympathetic Nervous System: Returns the body to a state of 'rest and digest' (e.g., decreasing heart rate and stimulating digestion).

How does the human eye achieve accommodation for distant objects?

1. Ciliary muscles relax.
2. Suspensory ligaments become taut (tighten).
3. The tension pulls on the lens, causing it to become less convex (flatter).
4. The refractive power of the lens decreases, focusing the image on the retina.

What is the function of the medulla oblongata in the brain?

The medulla oblongata acts as a conduction pathway for impulses between the spinal cord and the brain; it also controls vital involuntary functions such as heartbeat, breathing, and blood pressure.

What are the two main components of the human nervous system?

1. Central Nervous System (CNS)
   • Consists of the brain and the spinal cord.
2. Peripheral Nervous System (PNS)
   • Consists of cranial and spinal nerves that connect the CNS to the rest of the body.

Define a reflex arc and list its five essential components.

A reflex arc is the neural pathway that controls a reflex action. Its components are:

• Receptor: Detects the stimulus.
• Sensory Neuron: Transmits impulse to the CNS.
• Interneuron: Connects sensory and motor neurons in the CNS.
• Motor Neuron: Transmits impulse to the effector.
• Effector: The muscle or gland that carries out the response.

Distinguish between the sympathetic and parasympathetic nervous systems.

• Sympathetic Nervous System: Prepares the body for 'fight or flight' situations (e.g., increasing heart rate and dilating pupils).
• Parasympathetic Nervous System: Returns the body to a state of 'rest and digest' (e.g., decreasing heart rate and stimulating digestion).

How does the human eye achieve accommodation for distant objects?

1. Ciliary muscles relax.
2. Suspensory ligaments become taut (tighten).
3. The tension pulls on the lens, causing it to become less convex (flatter).
4. The refractive power of the lens decreases, focusing the image on the retina.

What is the function of the medulla oblongata in the brain?

The medulla oblongata acts as a conduction pathway for impulses between the spinal cord and the brain; it also controls vital involuntary functions such as heartbeat, breathing, and blood pressure.