Human Nervous and Endocrine System: Structure and Function

Gray Matter, Brain Structure and the Nervous System

Gray matter presents the modules and the first form of the nervous system. The white substance is located in the inner part, and the gray area is in the outer part, surrounded by the cerebrospinal fluid.

Functions of the Medulla

Reflex acts: actions carried out without the participation of the brain.

Sensitive impulses: twitches driving the brain and sending impulses to the motor organs and effectors.

Medulla Oblongata

The medulla oblongata is the prolongation of the spinal cord. It contains several zones of gray and white matter. Mobility of one body side is controlled by the opposite side of the brain. The medulla is responsible for regulating various vital functions, such as the heartbeat, blood pressure and pulmonary ventilation.

Cerebral Cortex

The brain comprises several parts: the medulla, the cerebellum and the cerebrum. The brain regulates sleep and wakefulness, dreams, and audio-visual reflexes. The hypothalamus is connected with the pituitary gland, and together they control homeostasis.

The Cerebellum

The cerebellum is located on the posterior part of the brain. Its surface has folds, and its gray and white matter form a branched structure known as the tree of life.

The cerebellum is in charge of receiving balance information and sending it to the brain, regulating muscle activity and maintaining balance. It coordinates motor commands from the cerebrum so that precise movements can be made.

Gametogenesis: Formation of Gametes

Gametogenesis is the process of gamete formation, where the gonads produce cells with reduced chromosome numbers. This special type of cell division is known as meiosis.

Ovules: the egg cell is a rounded cell with 23 chromosomes. It is large and has limited mobility compared with sperm. Its substances store nutrients to feed the embryo during the first days.

Healthy Lifestyle and Nervous System Care

An orderly life, with regular schedules and rest, is recommended. Avoid drug consumption. Intellectual activities, sports and mental care are beneficial.

• Balanced diet, including iodine.
• Avoid obesity.
• Avoid excessive stress.

Nervous tension does not provoke consequences when managed properly. Physiological, nervous and mental causes can be prevented by maintaining a relaxed, optimistic and positive attitude, and by avoiding overly critical thinking.

Endocrine System Disorders and Hormones

Endocrine-related diseases

Diabetes:

Diabetes is caused by decreased secretion of insulin. Several types exist; some patients need insulin injections and an adequate diet. Symptoms include weight loss, general weakness, sleepiness and thirst, and in extreme cases, death.

Dwarfism

Dwarfism is an endocrine disorder caused by insufficient production of growth hormone secreted by the pituitary gland.

Pituitary Gland (Hypophysis)

• Antidiuretic hormone: reduces the amount of water eliminated in urine.
• Oxytocin: contracts the uterus and muscles during delivery.
• Stimulating hormones: regulate other glands.
• Growth hormone: promotes elongation of bones and general growth.

Adrenal Glands

• Adrenaline: prepares the body for emergencies and activates the sympathetic nervous system.
• Corticoids: regulate several metabolisms.
• Aldosterone: controls the concentration of potassium and sodium.

Testes

• Androgens: produce and maintain sexual characteristics.

Thyroid

• Thyroxine: increases the intensity of metabolism.

Parathyroids

• Parathormone: regulates the amount of calcium and phosphorus in blood.

Pancreas

• Insulin: increases glucose utilization by muscles.
• Glucagon: stimulates the conversion of glycogen into glucose in the blood.

Ovaries

• Estrogens and progesterone: allow implantation of the embryo in the uterus.

218-192