Endocrine and Exocrine glands Flashcards
What are glands?
- Epithelial cells that produce secretions
- Ectodermal origin (the outer most three primary germinal layers of an embryo)
What is an exocrine gland?
A gland that secretes into ducts
What is an endocrine gland?
A gland that secretes directly into the blood stream
- Secretions known as hormones
Where can endocrine glands be found?
- Part of epithelial surface such as lining of digestive tract
- Separate organs such as thyroid or pituitary gland
What is the function of endocrine glands?
Regulation of bodily functions & maintain homeostasis
What is the chronic pattern of hormone secretion?
- Same amount is released every time continuously
What is the episodic pattern of hormone secretion?
- Similar level of secretions after a stimulus has been added
What is the acute pattern of hormone secretion?
- Secreted only when needed - amount varies depending on the stimuli
What is humoral regulation of hormone secretion?
- Blood-borne molecules (relating to bodily fluids)
- e.g. high glucose levels stimulates insulin secretion
What is the neural regulation of hormone secretion?
- Neurones stimulate hormone production
- e.g. SNS stimulates epinephrine release
What is the hormonal regulation of hormone secretion?
- Hormone secretion stimulates another hormone to be secreted
- e.g. hormones from the pituitary gland stimulate tests to make testosterone
What is calcitonin important for?
Controlling levels of calcium in the body
What does the parathyroid gland secrete?
Parathyroid hormone - extremely important for bone health
What is the effect of hyper-parathyroidism on bone?
Too much bone resorbed
What does parathyroid hormone do?
Helps bring calcium level up if low
What are the 2 ways exocrine glands can be classified by?
- Their structure
- Their method of secretion
How can you class exocrine glands by their structure?
- Unicellular glands
- Multicellular glands
What are the subtypes of multicellular exocrine glands?
- Secretory sheet = simple multicellular gland
- Pockets of gland cells set back from epithelial surface
What is a merocrine gland?
- Substance produced in vesicles - vesicles travel to surface and are secreted
What is an apocrine gland?
- Portion of cell stored in upper most part - separated from rest of cell and secreted
What is a holocrine gland?
- Completely separated - entire cell shed into duct
What is a serous secretion?
- Watery secretion containing enzymes
What is a mucous secretion?
- Secrete mucins which hydrate to form mucous
What are mixed glands?
- Contains both mucous and serous secretions
What are the major salivary glands?
Parotid, submandibular and sublingual
What organ in the body contains glands that are both exocrine and endocrine?
The pancreas
What is the endocrine part of the pancreas?
Islets of Langerhans:
- Beta cells (insulin)
- Alpha cells (glucagon)
- Delta cells (somatostatin and gastrin)
What percentage of the pancreas is endocrine cells?
About 1%
What percentage of the pancreas is exocrine cells?
About 99%
Why is surgical treatment of pancreatic cancer ineffective?
- Can’t operate on the pancreas as cutting into it makes pancreas start to self-destruct
What is the most common and most important endocrine disorder?
Diabetes mellitus
What causes Type 1: insulin dependent diabetes?
- Destructions on beta cells
- 5%-10% of all diabetic patients
- No insulin produced or very little
What causes Type 2: insulin resistant diabetes?
- Tissues loose their sensitivity to insulin so become ineffective
- Insulin is produced however tissues lose sensitivity to hormone
What systems in the body are affected by insulin?
Most systems of the body are affected by either type 1 or type 2 diabetes
What are some oral effects that can be caused by diabetes?
- Periodontitis, dry mouth and susceptibility to infections
What does hypofunction of the endocrine system mean?
- Reduced hormone release: not enough hormone to meet requirements
What does hormone resistance mean?
- Hormone is there however tissue loses sensitivity to hormone
What does hyperfunction of the endocrine system mean?
- Excessive hormone release: too much hormone is produced
When might endocrine changes be seen?
During pregnancy, menopause, stress, obesity and many more
