Please enable JavaScript.
Coggle requires JavaScript to display documents.
MaryBiraiEndocrineSystem (Endocrine Glands (Thyroid Gland (Structure &…
MaryBiraiEndocrineSystem
-
-
Overview
Locations:
- Endocrine gland: anterior pituitary, pineal gland, thyroid, parathyroid, adrenal
- Endocrine tissues/cells: GI tract, placenta, kidneys, skin, pancreas, gonads, thymus, hypothalamus, and heart
Function:
- Coordinate, control, and regulate body functions
- Organs secrete hormones. Hormones are chemical messengers that travel in the blood
- Endocrine cell: responsible for producing and releasing hormone molecules into the blood stream.
- Target cell: a given hormone only affect its target cells. Ability of target cell to respond to a hormone depends on presence of a specific receptor molecule on the target cell to which that particular hormone can bind.
Endocrine Glands
Thyroid Gland
Structure & Location
- Butterfly shaped in anterior neck on trachea, inferior to the larynx
- composed of arealor connective tissue
Hormones Produced
- Thyroid Hormone: increases the metabolic rate ( the rate at which the body uses oxygen to transform nutrients into energy)
- Calcitonin: active only in children; decreases osteoclast activity
Parathyroid Gland
Structure & Location:
- small, yellow brown. Lies on posterior surface of thyroid gland
- composed of 2 types of endocrine glands: parathyroid cells and oxyphil cells
Hormones Produced: Parathyroid hormone
- Increases blood calcium level when it detects that its low
Adrenal Glands
Structure & Location: Paired pyramidal shaped organs perched on superior surface of kideys.
- It is 2 adrenal glands in one: the adrenal medulla and the adrenal cortex.
Adrenal Cortex: Secretes steroid hormones
- Has 3 distinct layers listed externally to internally
- Zona Glomerulosa: secretes mineralcorticoids; helps the kidneys retain sodium and water
- Zona Fasciculata: secretes glucocorticoids - maintain blood glucose levels. "stress hormone"
- Zone Reticularis: secretes glucocorticoids & androgens. Androgens convert in other tissues to testosterone and estrogen.
Adrenal Medulla: is part of the autonomic nervous system, sympathetic branch.
- It is composed of specialized neurons.
- secretes epinephrine and norephinephrine
Pancreas
Structure & Function:
- islet cells
- Located in the posterior wall of the abdominal cavity in the left upper quadrant
- contains both exocrine and endocrine cells
- secretes digestive enzymes into the small intestine during digestion of food
Hormones:
- alpha cells: secrete glucagon which increases blood glucose level
- beta cells: secrete insulin which decreases blood glucose level
Anterior Pituitary
Structure & Location:
- Composed of glandular tissue
- Sits inferior to brain in depression in sella turcica of sphenoid bone
Hormones Produced
- Gonadotropins (Follicle stimulating hormone and luteinizing hormone); stimulates gonads to release hormone
- Growth Hormone: stimulates growth of all cells and epiphyseal plate
- Thyroid Stimulating Hormone: stimulates the thyroid to release hormone
- Prolactin: Stimulates the mammary glands to produce milk
- Adrenocorticotropic Hormone: stimulates the adrenal cortex to release hormones
Gonads
Structure & Function:
- Testes: interstitial endocrine cells
- Ovaries: ovarian follicle cells
- main source of steroid sex hormone
Hormones:
- Ovaries: secretes estrogen and progesterone
- Testes: secretes testosterone
Thymus
Structure & Function:
- located in lower neck and anterior thorax; lobed structure. Composed of epithelial reticular cells
Hormone
- produces thymic hormone
- thymic hormone causes T lymphocytes to become immunocompetent (ability to respond to a foreign cell)
- the T in T lymphocytes comes from thymus
Other Endocrine Structures
- Heart: atria contains atrial natriuretic peptide (ANP): a hormone that decreases excess blood volume, high BP, and high blood sodium concentration
- GI tract: has Enteroendocrine cells which are hormone secreting cells.
- Placenta: secretes several steroid and protein hormones during pregnancy.
- Kidneys: various cells produce erythropoietin ( signals bone marrow to increase RBC) and renin (indirectly signals adrenal cortex to secrete aldosterone.
- Skin: Vitamin D is steroid hormone essential for Ca+ metabolism