Hormonal Processes Flashcards
1
Q
biological characteristics of hormonal control (6)
A
- physiological regulators
- effective in minute quantities
- synthesized by cells which may/may not be located in a gland
- secreted and transported into bloodstream
- act on specific target cells (receptors present)
- trigger specific responses
2
Q
hypothalamus neuroendocrine site and pituitary (2)
A
- control of many physiological mechanisms
- important to reproduction
3
Q
hypothalamus (3)
A
- connect nervous-endocrine system
- produces peptides and amines
- controls part of the autonomic nervous system
4
Q
pituitary gland (2)
A
- anterior
- posterior
5
Q
posterior pituitary
A
- deposit site for molecules from the hypothalamus
6
Q
anterior pituitary
A
- a gland that receives stimulation from portal vessel and releases to general circulation
7
Q
hypothalamic portal vessel system
A
- connects to the anterior pituitary
8
Q
which reproductive hormones are regulated by the hypothalamus (4)
A
- gonadotropin releasing hormone (GnRH)
- prolactin-inhibiting or prolactin-releasing hormone (PIH/PRH)
- oxytocin
- melatonin
9
Q
characteristics of GnRH (4)
A
- small and simple structured polypeptide (only amino acids)
- produced by hypothalamus
- initiates a lot of things in gonads
- commercially available due to its ability to be synthesized easily
10
Q
GnRH function
A
- stimulates release of FSH and LH
11
Q
what can we conclude from the GnRH amino acid sequence across species (2)
A
- vastly different species all have some form of GnRH
- its conservation across species shows its functional importance as a molecule
12
Q
oxytocin function (3)
A
- induces uterine contractions
- induces milk ejection
- facilitates gamete transport
13
Q
melatonin function
A
- affects species reproductive cycles, making them seasonal
14
Q
PIH/PRH function
A
- inhibits or stimulates prolactin release
15
Q
which reproductive hormones are regulated by the anterior pituitary (3)
A
- follicle stimulating hormones (FSH)
- luteinizing hormones (LH)
- prolactin (PRL)
16
Q
which reproductive hormones are regulated by the posterior pituitary
A
- oxytocin
17
Q
what is a characteristic of hormones regulated by the hypothalamus (3)
A
- polypeptides
- relatively small
- peptide based hormones
18
Q
what is a characteristic of hormones regulated by the hypothalamus (2)
A
- glycoproteins
- peptide based hormones
19
Q
luteinizing hormone (LH) (2)
A
- relatively large glycoprotein (amino acids and carbohydrate residues) with alpha and beta chains
- molecule is difficult to synthesize
20
Q
which cells do LH target (2)
A
- leydig cells
- theca and granulosa cells
21
Q
LH function (2)
A
- stimulates follicular growth in female and spermatogenesis in male secretion
- targets leydig cells and theca/granulosa cells
22
Q
LH alpha and beta chain (2)
A
- alpha chain AA sequences similar between hormones within and between species
- beta chain AA sequence diverse between species; accounting for hormone and species specificity
23
Q
follicle stimulating hormone (FSH) (3)
A
- relatively large glycoprotein with alpha and beta subunits
- carbohydrate residue higher compared with LH
- generally conserved structure across species
24
Q
what cells do FSH target (2)
A
- sertoli cells
- granulosa cells
25
FSH function (2)
-stimulates ovulation and luteinization of ovarian follicles (CL) in females
- stimulates testosterone secretion in men
26
hormone carbohydrates chains
- content
- most important monosaccharide
- CHO content increases molecular weight (12 [LH] - 24% [FSH] of molecule)
- sialic acid
27
carbohydrate chains
- sialic acid (2)
- essential for biological activity and extending half life
- higher sialic acid content increases half-life of hormone
28
1/2 life of steroid hormones: proteins (3)
- steroid hormones bound to protein carriers in blood because they are lipophilic
- binding to proteins increases half-life of steroids
- only 5-10% of hormones present in unbounded form
29
prolactin structure (3)
- large molecular weight
- no CHO residues
- contains disulfide bonds (loop configuration) and cysteine residues
30
which cells do prolactin target (2)
- leydig cells
- sex glands
31
prolactin function (2)
- promotes lactation
- promotes maternal behaviour
32
gonadal steroids (4)
- produced by testis and ovaries
- similar biosynthesis pathway as lipids
- cholesterol based hormones
- effective orally as it is not digested
33
structure of steroid hormones (2)
- 4 rings with slight differences
- same cholesterol backbone
34
how does the structure of steroid hormones effect function
- steroid hormones can easily switch between forms
35
structural biological variation in steorid hormones (4)
- # of double bonds in the A ring
- ketone vs hydroxyl group at C3
- C10 methyl group present or missing
- C17 attachment of 2 C atoms or hydroxyl groups
36
structural biological variation in steroid hormones (4)
- # of double bonds in the A ring
- ketone vs hydroxyl group at C3
- C10 methyl group present or missing
- C17 attachment of 2 C atoms or hydroxyl groups
37
characteristics of hormones secreted by reproductive organs (2)
- fat-related hormones
- cholesterol based
38
hormones secreted by reproductive organs (4)
- estrogen
- progesterone
- testosterone
- prostaglandin (PG)
39
prostaglandin (PG) structure (2)
- unsaturated fatty acid
- contains double bonds that bend molecule
40
prostaglandin (PG) characteristics (3)
- secreted by most body tissues as its precursor is present in all cells
- paracrine and endocrine action; can enter bloodstream or affect adjacent cells
- very short half life
41
PG function (3)
- causes uterine contractions
- assists sperm in transport in female tract
- causes regression of corpus luteum (luteolysis)
42
androgen binding protein (ABP)
- structure
- large glycoprotein
43
ABP location
- sertoli cells
44
what is ABP production important for (3)
- binds testosterone to increase concentration in seminiferous tubules
- initiation of spermatogenesis
- puberty in young animals
45
schematic mechanism of steroid hormones (2)
- normally crosses cell membrane from blood vessel as its lipophilic
- nucleus receptor allows steroid to enter nucleus
46
schematic mechanism of protein hormones (2)
- does not cross membrane
- attaches to receptor from blood vessel that triggers a secondary messenger pathway that signals to nucleus to produce something
47
example of protein hormone activity (2)
1. LH molecule binds to receptor on Leydig cell
2. triggers secondary messenger pathway that signals nucleus to produce testosterone
48
schematic mechanism of nerve pathway example (3)
1. teat stimulation triggers nerve pathway to hypothalamus
2. oxytocin stored in posterior pituitary from hypothalamus is released into bloodstream
3. oxytocin stimulates muscles in teat to eject milk
49
receptors and 2nd messenger pathways (2)
- hormones dock on receptors and trigger conformation changes to the receptor
- triggers changes to cAMP, protein kinases and phosphorylation pathways
50
G protein coupled receptor (4)
- 7 trans-membrane domains
- normally linked with adenylate cyclase (AC)
- converts ATP to cAMP
- protein kinase A or C pathway leads to phosphorylation/ transcription
51
steroid receptors (3)
- nuclear or cytoplasmatic
- associated with chaperones (HSP)
- upon binding, steroid is transferred to nucleus
