Endocrine System: Adrenals, Pancreas, and More
The Endocrine System: A Closer Look
Adrenal Glands
The adrenal glands are two small glands located in the abdomen, on either side of the vertebral column, atop the kidneys. They secrete adrenaline and noradrenaline, which act in stressful situations, promoting alertness and wakefulness. They also secrete corticosteroids:
- Glucocorticoids: Involved in the metabolism of carbohydrates, proteins, and fats, and block inflammatory responses to allergic reactions.
- Androgens (testosterone): Have a masculinizing effect.
- Epinephrine: Stimulates involuntary movements or processes of the body, such as breathing, heart activity, blinking, and digestive organ functions.
- Norepinephrine: Has either no effect or an antagonistic action.
Pancreas
The pancreas is a gland located in the upper abdomen, below the stomach. It consists of two types of glandular tissue: endocrine tissue, made up of Langerhans cells that secrete insulin and glucagon; and exocrine tissue, which secretes pancreatic juice released into the duodenum. It also secretes amylase and peptidase enzymes.
- Insulin: The regulation of insulin secretion depends on blood glucose levels.
Sex Glands (Gonads)
Sex glands are glands that produce gametes and hormones, either male (testes) or female (ovaries).
- Female Hormones:
- Estrogen: Stimulates the growth and development of female sexual organs and breast development.
- Androgens (testosterone): Stimulates female libido, pubic hair development, and axillary hair growth.
- Progesterone: Assists in the gestation process.
- Male Hormones:
- Testosterone: Development of male sexual apparatus, including growth of pubic hair, voice changes, etc.
Physiology of the Neuroendocrine System
The Neuron
A neuron is one of the most important cells in the nervous system. It is formed by the cell body (soma) and extensions of two types: dendrites and axons. The axon is responsible for conducting the nerve impulse to other neurons (sensory, motor, and interneurons).
Nerve Impulse Transmission
Synapses are specialized contact zones between neurons (presynaptic and postsynaptic). They facilitate nerve impulse transmission.
Regulation of Hormone Secretion
Feedback: Endocrine glands secrete a hormone that acts on the effector or target organ, which gradually increases its function. When hormone levels become excessive, a feedback mechanism lessens the hormone secretion.
Pathologies
Epilepsy
Epilepsy is a condition characterized by brain dysfunction, often accompanied by loss of consciousness and convulsions.
- Grand Mal: Characterized by generalized convulsions preceded by an aura.
- Petit Mal: Features include loss of consciousness without convulsions.
Alzheimer’s Disease
Alzheimer’s Disease is a genetic disorder caused by the destruction and disappearance of neurons in the cerebral cortex, triggering progressive and irreversible dementia.
Parkinson’s Disease
Parkinson’s Disease (Paralysis Agitans) is a chronic and progressive neurodegenerative disease of the nervous system, causing impaired mobility. It results from a decrease in the production of dopamine, a neurotransmitter involved in controlling the speed and precision of movements.
Diabetes Mellitus
Diabetes Mellitus is a metabolic disease caused by a partial or complete reduction in insulin secretion.