Human Body Systems: Nervous and Endocrine System Functions

Interplay of Body Systems

Sensory organs capture information as a stimulus and transmit it to the nervous system, which receives, processes, and develops a response. This response is then transmitted to effector organs, which carry out the action.

The Musculoskeletal System

This system controls the movement of the body.

The Endocrine System

This system produces hormones that regulate various body functions.

The Nervous System

Neurons: The Building Blocks

Neurons are specialized cells designed to receive, integrate, and transmit information.

Nerve Impulse

A nerve impulse is a slight electrical current produced by the arrival of information.

Types of Neurons

• Sensory Neurons: Located in sensory organs; they capture stimuli.
• Effector Neurons: Stimulate muscles and glands.
• Interneurons: Connect the aforementioned neurons.

Divisions of the Nervous System

• Central Nervous System (CNS): Consisting of the brain and spinal cord.
• Peripheral Nervous System (PNS): Composed of 12 cranial nerves and 31 spinal nerves emerging from the spinal cord.

The Central Nervous System (CNS)

The CNS, consisting of the brain and spinal cord, is protected by coverings:

• Bony Case: The skull and spine (external protection).
• Meninges: Internal layers including the dura mater, arachnoid mater, and pia mater.

The Brain

The brain is divided into two hemispheres, united by the corpus callosum. Its outer layer features fissures, such as the Fissure of Rolando and the Fissure of Sylvius.

Gray Matter

Measuring 2 to 3 cm thick, gray matter consists of nerve cell bodies. Here, responses are elaborated, and sensations are interpreted.

Brain Stem

The brain stem is located beneath the cerebrum, connecting it to the spinal cord. Sensory information is processed in the thalamus, which then sends impulses to the cerebral cortex. The hypothalamus regulates certain visceral functions. The pituitary gland regulates the secretion of hormones.

Cerebellum

The cerebellum coordinates voluntary movements. It helps guide our body and maintain balance.

Medulla Oblongata

Located at the base of the brainstem, connecting to the spinal cord, the medulla oblongata controls involuntary visceral functions, such as heart rate. Damage to this area can lead to paralysis, coma, or death.

The Spinal Cord

The spinal cord is a cylindrical nervous structure, approximately 1 cm in diameter and 50 cm long. It is crucial for elementary body responses, especially in risk situations requiring a prompt reaction (reflexes).

The Autonomic Nervous System (ANS)

The ANS regulates involuntary visceral functions. It is formed by a group of nerve fibers and has two types:

• Sympathetic Nervous System: Activates organ functioning; for example, it slows digestion.
• Parasympathetic Nervous System: Activates digestion and relaxes the functioning of other organs.

The Endocrine System and its Interaction

The endocrine system acts in conjunction with the nervous system. It secretes hormones in response to stimuli. These hormones are transported by the blood from glands to target organs where they are needed. The action of hormones produces a slow but lasting response, regulating vital functions such as growth.