30 Questions
What is the primary function of the thyroid gland?
Synthesis of thyroid hormones
What is the most common cause of hyperthyroidism?
Graves' disease
What is the primary function of the parathyroid glands?
Not mentioned in the content
What is the term for the process by which cells take up and decarboxylate amine precursors?
Amine precursor uptake and decarboxylation
What is the term for the enlargement of the thyroid gland due to iodine deficiency?
Endemic goiter
What is the approximate weight of the adrenal gland?
18g
What is the term for the inflammation of the thyroid gland?
Thyroiditis
What is the term for cells that produce serotonin and other amine derivatives?
APUD cells
What is the condition characterized by a deficiency of cortisol and aldosterone?
Addison's disease
What is the term for the outer layer of the adrenal gland?
Capsule
What is the function of the endocrine system?
To secrete hormones into the bloodstream
What is the term for a chemical messenger that targets a specific group of cells?
Hormone
What is the term for a cell that produces a hormone that stimulates or inhibits its neighbor?
Paracrine cell
What is the location of the pituitary gland?
At the base of the brain
What is the term for the component of the pituitary gland that produces hormones that regulate growth and development?
Pars distalis
What is the term for the cells that produce growth hormone in the pituitary gland?
Somatotrophs
What is the result of oversecretion of growth hormone in childhood?
Giantism
What is the term for the condition that results from oversecretion of growth hormone in adulthood?
Acromegaly
What is the term for the part of the pituitary gland that consists of cysts filled with colloid?
Pars intermedia
What is the weight of the hypothalamus?
Approximately 0.7g
What is the primary function of the hypothalamus?
To maintain homeostasis in the body
Which of the following is NOT a function of the hypothalamus?
Control of skeletal muscles
What is the role of the pars nervosa?
To store and release hormones
What are Herring bodies?
Distensions of axons in the pars nervosa
What is the function of pituicytes?
To support the axons of the pars nervosa
What is the function of the pineal gland?
Unknown
What is the approximate weight of the thyroid gland?
25g
What is the location of the hypothalamus in the brain?
Between the pituitary gland and thalamus
What is the primary role of the hypothalamus in hormone production?
To stimulate hormone production
What is the function of corpus arenaceum?
Unknown
Study Notes
Thyroid Gland
- Built with two lobes connected by a necking
- Composed of follicles, colloid, blood vessels, and parafollicular cells (C cells)
- Function: Synthesis of thyroid hormones (T4 and T3)
- T3: triiodothyronine
- T4: thyroxine
Thyroid Hormones
- Produced by principal cells (clear cells)
- Regulated by parafollicular cells (C cells)
Thyroid Disorders
- Graves' disease: autoimmune disease, 80-90% of all hyperthyroidism, mostly affects women
- Thyroiditis: inflammation of the thyroid, mostly chronic-autoimmune, presents as goiter
- Endemic goiter: enlargement of the thyroid gland due to iodine deficiency in the diet
Parathyroid Gland
- Composed of oxyphil cells and principal (chief) cells
- Function: regulates water and electrolyte balance
Adrenal Gland
- Weight: approximately 18g (adrenal cortex) and 4g (adrenal medulla)
- Composed of adrenal cortex (95% of the gland) and adrenal medulla (5%)
- Adrenal cortex: divided into three zones - zona glomerulosa, zona fasciculata, and zona reticularis
- Function: regulates water and electrolyte balance
Endocrine System
- Includes endocrine glands and their hormones
- Function: secretes hormones into the bloodstream to regulate various bodily functions
- Hormones: chemical messengers that target specific groups of cells to stimulate or inhibit activity
Endocrine Glands
- Locations: pituitary gland, thyroid gland, parathyroid gland, adrenal gland, pineal gland, and others
- Hormones: proteins, glycoproteins, small peptides, amino-acid derivatives, and steroids
Communication Pathways
- Autocrine: cell produces hormone that stimulates or inhibits itself
- Paracrine: cell produces hormone that stimulates or inhibits its neighbor
- Juxtacrine: cells sit side by side, one has hormone on its surface, the other has the receptor
Pituitary Gland
- Weight: approximately 0.5-1g
- Diameter: approximately 1 cm
- Components: adenohypophysis (anterior lobe) and neurohypophysis (posterior lobe)
Pituitary Gland Cells
- Chromophils: acidophils and basophils
- Chromophobes: non-staining cells
- Adenohypophysis: produces hormones that regulate various bodily functions
- Neurohypophysis: stores and releases hormones produced by the hypothalamus
Pituitary Hormones
- Growth hormone (GH): regulates growth and development
- Oversecretion: gigantism in childhood and acromegaly in adulthood
- Undersecretion: dwarfism in childhood
Hypothalamus
- Weight: approximately 0.7g
- Diameter: approximately 1 cm
- Location: center of the brain, between the pituitary gland and thalamus
- Function: regulates hormone production, body temperature, thirst, appetite, emotions, sleep cycles, sex drive, and other bodily functions
- Acts as the connector between the endocrine and nervous systems
Pineal Gland
- Weight: approximately 0.2g
- Length: 5-8 mm
- Width: 3-5 mm
- Composed of pinealocytes, interstitial glial cells, and corpus arenaceum (brain sand)
- Function: regulates sleep-wake cycles and reproductive hormones
Learn about the structure and function of the thyroid gland, including its composition, hormonal synthesis, and related diseases.
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