Overview of Hormonal Secretion Flashcards
What type of secretion is hormonal?
Endocrine = into blood
What are the X2 types of hormone delivery into the blood?
Explain each or these.
1) endocrine = hormone released from cell to blood
2) neuroendocrine = hormone released from nerve into blood
Name some examples of neuroendocrine secretion.
1) hypothalamus
2) posterior pituitary
3) adrenal medulla
Explain each of the following:
1) merocrine
2) apocrine
3) holocrine
4) endocrine
5) paracrine
6) autocrine
1) merocrine = hormone filled vesicles in cells fuse with cell membrane
2) apocrine = hormones create vesicles for release from cell membrane
3) holocrine = cell dies to release hormone
4) endocrine = hormone release into blood
5) paracrine = hormones released act locally
6) autocrine = hormone released acts on the same cell which released it
What are the X3 main classes of hormones?
1) proteins/peptides
2) steroids
3) amines
How do peptide/protein hormones circulate in the blood?
Unbound as they are polar
Why is the rate of steroid hormone release slow?
It relies on the rate of production as they are not stores in the cells of the gland
How do steroid hormones circulate on the blood?
Bound to albumin as they are all derived from fat soluble lipids
What is the general structure of a steroid?
X3 six carbon ring structures
X1 five carbon ring structure
What are amine hormones?
They are hormones derived from tyrosine
Give examples of amine hormones.
Catecholamines
Thyroid hormones (T3 and T4)
How are thyroid hormones stored?
In the thyroid bound to thyroglobulin
How are thyroid hormones found in blood?
Circulating bound to proteins as they are lipid soluble
How do the catecholamines circulate in blood?
Freely and unbound as they are are water soluble
What fourth, smaller group of hormones do thromboxane and prostaglandins fall under?
Eicosanoids
What generic precursor are ecosanoids synthesised from?
Arachidonic acid
Which groups of hormones are linked to neurosecrectory cells?
Proteins and catecholamines
Where will the receptor be found for protein and catecholamines hormones?
Why?
On the cell surface as these type of hormones are polar therefore can not cross lipid membranes
Where will the receptor be found for steroid and thyroid hormones?
Why?
Intracellularly and these type of hormones are lipid-soluble (non-polar) therefore can cross the lipid membrane
What is another name for the anterior pituitary?
Adenohypophosis
What is another name for the posterior pituitary?
Neurohypophysis
From what buffalo cavity outgrowth does the anterior pituitary form?
Rathke’s pouch
From what does the posterior pituitary evaginate from to form?
The diencephalon (forebrain)
How is posterior pituitary hormone release controlled?
Directly from neural projections from the hypothalamus
