Endocrine System Disorders and Central Nervous System Overview

Endocrine System Disorders

Major Diseases and Their Causes

The endocrine system regulates numerous physiological processes through hormone secretion. Several disorders arise from dysfunctions in hormone production or action.

• Diabetes Mellitus Type 1: An autoimmune disorder where the immune system destroys insulin-producing beta cells in the pancreas, leading to insulin deficiency.

• Diabetes Mellitus Type 2: Characterized by insulin resistance and relative insulin deficiency, often associated with obesity and lifestyle factors.

• Gigantism: Caused by excessive secretion of growth hormone (GH) from the pituitary gland during childhood, resulting in abnormal growth of bones and tissues.

• Graves Disease: An autoimmune disorder leading to hyperthyroidism due to antibodies stimulating the thyroid gland to produce excess thyroid hormones.

• Pituitary Dwarfism: Results from insufficient growth hormone production by the pituitary gland during childhood, causing stunted growth.

Example: A child with pituitary dwarfism will have normal body proportions but significantly shorter stature compared to peers.

Hormone Production by Major Glands

Endocrine glands secrete specific hormones that regulate body functions.

• Thyroid Gland: Produces thyroxine (T4) and triiodothyronine (T3), which regulate metabolism, and calcitonin, which lowers blood calcium levels.

• Parathyroid Gland: Secretes parathyroid hormone (PTH), which increases blood calcium levels.

• Pancreas: Produces insulin (lowers blood glucose) and glucagon (raises blood glucose).

• Pituitary Gland: Releases multiple hormones, including growth hormone (GH), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), prolactin, follicle-stimulating hormone (FSH), and luteinizing hormone (LH).

Additional info: The pituitary gland is often called the "master gland" because it regulates other endocrine glands.

The Central Nervous System (CNS)

Brain Regions and Their Functions

The brain consists of several regions, each with specialized functions essential for survival and cognition.

• Medulla Oblongata: Controls vital autonomic functions such as heart rate, breathing, and blood pressure.

• Brain Stem: Includes the medulla, pons, and midbrain; responsible for basic life functions and relaying information between the brain and spinal cord.

• Pons: Assists in regulating breathing and serves as a relay station between different parts of the brain.

Example: Damage to the medulla can result in loss of autonomic control, which may be fatal.

Functions of Cerebrospinal Fluid (CSF)

Cerebrospinal fluid is a clear fluid that surrounds the brain and spinal cord, providing several key functions:

• Protects the CNS by cushioning against physical impacts.

• Removes metabolic waste from the brain.

• Maintains stable chemical environment for neural tissue.

Diencephalon Regions

The diencephalon is a central brain region containing:

• Thalamus: Acts as a relay station for sensory information.

• Hypothalamus: Regulates homeostasis, including temperature, hunger, and hormone release.

• Epithalamus: Contains the pineal gland, which secretes melatonin to regulate sleep cycles.

Meningitis

Meningitis is the inflammation of the meninges, the protective membranes covering the brain and spinal cord. It can be caused by bacterial, viral, or fungal infections and may result in severe neurological damage if untreated.

Blood-Brain Barrier and the Vomiting Center

The blood-brain barrier is a selective barrier that protects the brain from harmful substances in the blood. The vomiting (emetic) center in the medulla is one of the few areas where the blood-brain barrier is weak, allowing it to detect toxins and trigger vomiting.

Peripheral Nervous System (PNS)

Autonomic Division

The autonomic nervous system is a subdivision of the PNS that controls involuntary bodily functions, such as heart rate, digestion, and respiratory rate. It is further divided into the sympathetic and parasympathetic systems.

Sensory Division and Visceral Sensory Neurons

The sensory division of the PNS includes visceral sensory neurons, which transmit information from internal organs to the CNS, allowing the body to monitor and respond to changes in the internal environment.

Alzheimer's Disease

Overview and Effects

Alzheimer's disease is a progressive, degenerative neurological disorder that leads to dementia. It is characterized by memory loss, confusion, mood changes, and language impairment. The disease causes the brain to shrink and disrupts communication between neurons, leading to cognitive decline.

• Progressive loss of memory and cognitive abilities

• Behavioral changes such as confusion and mood swings

• Language impairment and difficulty performing daily tasks

• Physical changes in the brain, including shrinkage and loss of neural connections

Additional info: Alzheimer's disease is associated with abnormal protein deposits (amyloid plaques and neurofibrillary tangles) in the brain.