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Chapter 21

Endokrin Sistem

Chapter 21

The Endocrine System

The endocrine system is made of glands and organs that produce and secrete hormones. Hormones are chemical signals that act as messengers between …
The endocrine system is composed of glands, tissues, and organs distributed throughout the body. Endocrine glands are ductless glands that secrete …
A signaling cascade is a sequence of events that transfers information within or between cells, resulting in a response in the target cell. Hormones are …
Hormones can be classified into steroids, eicosanoids, amino acid-based derivatives, and peptide hormones based on their structures. Steroids and …
Water-soluble hormones cannot move across the plasma membrane, so they use protein receptors that span the membrane to trigger intracellular signaling …
Hormones bind to receptors on a target cell’s surface or interior and initiate various cellular …
Hormone secretion is regulated by different types of signals, including neural, humoral, and hormonal stimuli. Neural stimuli are triggered by the …
The pituitary gland is a small endocrine organ located in the sphenoid bone under the hypothalamus. Primarily, the pituitary in adults has two distinct …
The small, pea-sized pituitary gland is located at the base of the brain. It is crucial in regulating various bodily functions, from growth to …
The thyroid gland is a small, butterfly-shaped gland. It covers the anterior surface of the trachea in the neck region. It has two lateral lobes connected …
Low blood levels of the thyroid hormones — triiodothyronine (T3) and thyroxine (T4) — signal the hypothalamus to release the …
The thyroid hormone, or TH, is essential for the normal development and maturation of the skeletal, muscular, and nervous systems during fetal and …
Calcitonin is a polypeptide hormone that regulates calcium levels in body fluids. The parafollicular cells or C cells are present in the follicular …
The thyroid gland's posterior surface contains two embedded pairs of parathyroid glands. They are separated from the thyroid gland by a dense …
The adrenal or supra-renal glands are paired, pyramid-shaped glands located above the kidney and in line with the twelfth rib.  When the body …
The adrenal hormones are crucial for the body's electrolyte balance and stress response. The adrenal cortex produces over two dozen types of …
Adrenal gland disorders occur when the concentration of adrenal hormones produced is too high or too low. Adrenal insufficiency occurs when the adrenal …
The pineal gland is a small endocrine gland named for its pinecone shape. This gland is located on the roof of the third ventricle within the …
The gonads, the testes in males, and the ovaries in females produce gonadal hormones. Testosterone is the primary male gonadal androgen. It is responsible …
The pancreas is a glandular organ in the abdominal cavity that is part of the digestive and endocrine systems. It consists of exocrine and endocrine cells …
The pancreatic hormones glucagon and insulin regulate blood glucose levels. Between meals or during fasting, the blood glucose levels drop, triggering the …
Diabetes mellitus is a chronic metabolic disorder characterized by high blood glucose levels due to inadequate insulin production, insulin resistance, or …
In Type 2 or insulin-independent diabetes, the insulin receptors on the cells stop responding to insulin, developing resistance to insulin functions. This …
The thyroid is a bilobated endocrine gland localized at the base of the neck, producing the thyroid hormones T3, T4, and calcitonin. T3 and T4 are …
Immunofluorescence is a well-established technique for detection of antigens in tissues with the employment of fluorochrome-conjugated antibodies and has …
Immunohistochemistry is the most commonly used method for the identification and visualization of tissue antigens in biological research and clinical …