Topic D-Endocrine system, endocrine Diseases and the eye part 1-2 Flashcards
What is a hormone?
Signaling molecules, produced by glands in multicellular organisms, that are transported by the circulatory system (blood vessels, lymph nodes) to target distant organs to regulate physiology and behaviour.
eg. estrogen, insulin, thyroid hormone
what are the location of the 6 major endocrine organs you have to rmb?
- pituitary gland
- thyroid gland
- adrenal gland
- pancreas
- ovaries
- testes
What are the 3 different mechanisms which hormone secretion can be stimulated by?
- Hormonal stimuli
Hormone secretion stimulated by other hormones - Humoral stimuli
hormone secretion stimulated by low ions / nutrients in blood - Neural stimuli
hormone secretion stimulated by Nerve impulses
Where is the pituitary gland located and what are its 2 functional lobes?
hypothalamus
anterior and posterior pituitary
what are the 5 Hormones of the Anterior Pituitary?
ATFLG
- Adrenocorticotropic hormone (ACTH)
- Thyroid stimulating hormone (TSH)*
- Follicle-stimulating hormone (FSH)*
- Luteinizing hormone (LH)*
- Growth hormone (GH)
what is the relationship between hypothalamus and anterior pituitary?
humoral stimuli
eg growth hormone releasing hormone in hyp. stimulates release of growth hormone in ant. pituitary
what are the 2 Hormones of the posterior Pituitary?
Antidiuretic hormone (ADH) -ADH causes kidneys to reabsorb more water, thus urine volume & blood volume - In large amounts, causes vasoconstriction leading to increased blood pressure (vasopressin)
Oxytocin
-Stimulates contractions of the uterus
during labor
-Causes milk ejection (lactation)
what is the relationship between hypothalamus and posterior pituitary?
Hypothalamus produces
ADH & oxytocin that are transported
to the post. pituitary
-ADH and oxytocin are released from
the post. pituitary in response to
***nerve impulse from the hypothalamus
-The hypothalamus produces releasing
and inhibiting hormones which regulate the release of hormones
from the anterior pituitary
where is the thyroid gland located and what are the 3 hormones it produces?
- Found at the base of the throat
- Produces thyroid hormones (T4, T3) & calcitonin
what is the function of thyroid hormones T4 (thyroxine) and T3 (Triiodothyronine)
-Major metabolic hormone
-Controls the rate at which glucose is oxidized and converted to
chemical energy to be used by all body cells
- Secreted by the thyroid follicular cells upon stimulation by TSH (prod in ant. pituitary)
- *hormonal stimuli
**too much thyroid hormone= hyperthyroidism= hyperactivity
what is the function of calcitonin?
- Stimulate bone deposition; decrease Calcium level
- Secreted by parafollicular cells (also called C cells)
-Secreted in response to high blood calcium level **(humoral
stimuli
-Antagonistic effect to parathyroid hormone
where are the parathyroid glands located and what hormone does it secrete? what kind of stimuli here?
-located at posterior of the thyroid
-Secrete parathyroid hormone (PTH) in response to low blood
calcium level **(Humoral stimuli)
what is the function of PTH?
Function - raise calcium levels in the blood by:
- Stimulating osteoclasts to remove calcium from bone
- Stimulate the kidneys and intestine to absorb more calcium
what are the 2 kind of glands in the pancreas?
- exocrine glands
Secrete digestive enzymes into the
duodenum for digestion of food - endocrine glands
• Scattered within exocrine glands
called islets of Langerhans
• Over 1 million islets in human
pancreas
what are the 2 hormones prod by the islets of Langerhans that regulate bld glucose levels? what are their functions?
- Insulin – secreted by beta (β) cells
Function: decrease blood glucose level (hypoglycemic effect) - Glucagon – secreted by alpha (α) cells
Function: increase blood glucose level (hyperglycemic effect)
