Principles of Endocrine Control Flashcards
1
Q
Define glands:
A
Epithelial tissue derivatives specialised for secreting
2
Q
Define secretion:
A
By chemical release from a particular type of cell upon stimulation
3
Q
Define endocrine:
A
Internal secretion where secretion enters bloodstream (ductless glands)
4
Q
Define exocrine:
A
Glands with ducts which channels it secretion
5
Q
What sort of gland is the pancreas?
A
Exocrine and endocrine
6
Q
Define hormone:
A
Chemical messengers secreted into the blood by endocrine glands in response to signal exerting their effect on the target cells have receptor that bind with the hormones
7
Q
What are the two main subjects that we classify hormones on?
A
- Based on solubility
- Based on structure
8
Q
How do we class hormones based on their solubility?
A
- hydrophilic or water-soluble (peptides and catecholamines, adrenaline and noradrenaline)
- Lipophilic or lipid soluble (Steroid and thyroid hormones)
9
Q
How do we class hormones based on their structure?
A
- Peptides (chain of specific amino acids)
- Amines (derivatives of amino acids, tryptophan or tyrosine)
- Steroids (Cholesterol derived lipids)
10
Q
How are peptide produced?
A
Normal protein synthesis
11
Q
How is steroids produced?
A
Modification of cholesterol molecule by enzymes
12
Q
How do peptides travel in the body?
A
Blood in solution
13
Q
How do steroids travel in the body?
A
Blood bound to plasma proteins
14
Q
Can peptides enter cells?
A
No as lipid bilayer cell membrane
15
Q
Can steroids enter cells?
A
Yes, easily
16
Q
How do peptides effect a cell if they can’t enter on?
A
They bind to cell surface receptors
17
Q
Does peptides or steroid bind to an intracellular receptor?
A
Steroids
18
Q
What do peptides do?
A
Tigger event on inside surface of membrane
19
Q
What do peptides act as?
A
Second messenger system
20
Q
What do steroids do?
A
Act on DNA to alter cell function
21
Q
Which is fast acting steroids or peptides?
A
Peptides
22
Q
Which is slow acting steroids or peptides?
A
Steroids
23
Q
What are examples of peptide hormone signal transduction?
A
-Cyclic AMP
-Protein kinase activity
-Calcium/Phosphoinostides
Cyclic GMP
24
Q
What kind of receptors fo cyclic AMP, cyclic GMP and calcium ions have?
A
G-protein coupled receptors
25
Give an example of G-protein coupled receptors for cyclic AMP?
Adrenaline, noradrenaline,
glucagon, FSH, LH, TSH, Calcitonin,
parathyroid hormone, antidiuretic
hormone (ADH)
26
Give an example of G-protein coupled receptors for cyclic GMP?
Atrial naturetic hormone, nitric oxide
27
What kind of receptors fo protein kinase
insulin, prolactin and growth hormones
28
Give an example of G-protein coupled receptors for calcium ions?
Adrenaline, noradrenaline,
| angiotensin II, ADH, GnRH, TRH
29
Finish the sentence:
| Activation of the secondary messenger is a....
universal mechanism
30
What is the secondary messenger used by?
variety of extracellular messengers in addition to hydrophilic hormones
31
How does a steroid hormone work?
- Hormone passes through cell membrane
- Binding to transcription control of gene
- Transcription beings
- mRNA produced
- Leading to cellar response
32
List 11 human endocrine organs?
- Hypothalamus
- Pituitary
- Thyroid
- Parathyroid
- Adrenal cortex
- Adrenal Medulla
- Kidney
- Stomach
- Pancreatic Islets
- Duodenum and Jejum
- Ovary
- Testis
33
What is the overall role of the endocrine system?
- Metabolism, water and electrolyte balance
- Stress response
- Growth and development
- Reproduction
- Red cell production
- Coordination of circulation
- Coordination of digestion
34
What does the gland testis release?
Testosterone
35
What is the function of the testis?
- Masculinises the reproductive tract and external genitalia
- Promote growth and maturation of reproductive system at puberty
- Spermatogenesis
- Develops sex drive
- Secondary sexual characteristics
36
How do we have an increase of testosterone at puberty?
Gonadotropin-releasing hormone (GnRH) increases the LH on the leydig cells which increase the testosterone levels.
37
How do we have an increase in spermatogenesis at puberty?
GnRH increases FSH on the sertoli cells which increases spermatogenesis. Also testosterone increases spermatogenesis
38
Is there a negative feedback systems in the control of testicular function?
Yes increase in testosterone decreases the level of LH and GnRh if too high
39
What hormone is recreated by sertoli?
inhibin
40
What does inhibin control?
Production of FSH by anterior pituitary bu negative feedback
41
What gland produces oestrogen and progesterone hormones?
Ovaries
42
What is the function of ovaries?
- Maturation and maintenance of reproductive system
- Female secondary sexual characteristics
- Ova maturation and release
- Transport of sperm to site of fertilisation
- Preparing uterus for development of embryo and foetus
- Breasts ability to produce milk
43
How do we increase the levels of oestrogen and progesterone in puberty?
GnRH increase release of LH and FSH at the ovarian follicles and corpus luteum which increases the oestrogen and progesterone levels
44
Is there a negative feedback system in the control of ovarian function?
Yes, Oestrogen and progesterone levels increases the less GnRH is produced
45
What does the hypothalamus-pituitary- gonad axis regulate?
Production of testosterone by testes in males and
| oestrogen and progesterone by ovaries in females.
46
What is meant by autocrine?
Cell secretes a chemical messenger and that chemical messenger has an effect on the same cell as the cell has a receptor for that
47
What is meant by paracrine?
Chemical messenger is produced from one type of cell which acts locally but on a different type of cell
48
Where are the hypothalamus and pituitary located?
In the brain
49
What is the hypothalamus and pituitary part of?
The central nervous system
50
What is the structure of pituitary?
Small pouch like structure in a bone cavity
51
What is the structure of the hypothalamus?
Doesn't really have one
52
What are the hypothalamus and pituitary linked by?
pituitary stalk
53
What is the size of the pituitary?
Size of a pea 1g
54
What is the posterior pituitary?
neural ends of neurones that originated in the hypothalamus
55
What is the anterior pituitary?
glandular cells which produce various hormones
56
What is the connection called between the anterior pituitary and hypothalamus?
Vascular connection
57
What is the vascular connection?
Neurones in the hypothalamus produce certain hormones which travel through this connection to stimulate the cells in the pituitary to produce their own hormones
58
Where is GnRH produced?
Hypothalamus
59
What is GnRH?
Stimulates release of gonadotopes
60
What are the leydic cells in testes?
Site of production of testes
61
What are the Sertolli cells in testes?
Site of production of sperm
62
How is the scrotum held in position?
Spermatic cords
63
What is the testes covered by?
Fibrous capsule
64
What are fibrous capsules made out of?
leydig cells and sertolli cells
65
What is the uterus?
strong muscular structure present in the pelvic region
66
What are the ovaries made out of?
many sac like structures called ovarian follicles
67
What are ovarian follicles?
Contain oocyte and cells that produce oestrogen and progesterone
68
What is connected to the ovaries?
Fallopian tubes
69
What is connected to both the sides of the uterus?
Fallopian tubes
70
Describe the development of the ovarian follicles:
- Primordial follicle (13-50 years)
- Primary follicle (prenatal follicle 45 days)
- Secondary follicle (antal follicle)
- Graafian follicle (mature follicle)
- Ovulation
71
What is the lining of uterus called?
endometrium
72
Are there low or high levels of oestrogen at the pre-ovulation stage?
Low
73
What stimulates the development of follicles?
FSH
74
What causes ovulation?
LH
75
What is oestrogen?
steroid sex hormone which developed sex characteristics and thin cervical tissue
76
What is progesterone?
Steroid sex hormone causes corpus luteum after ovulation
77
What is ovulation?
releasing of the egg from ovaries at 14th day of 28 day cycle
78
What happens to the corpus luteum (CL) if no fertilisation?
- CL degenerates spontaneously
- Progesterone levels fall
- Uterus loses endocrine support
- Menstruation
- FHS and LH work again on follicles
79
What happens to the corpus luteum (CL) if fertilisation?
- CL maintained by hCG from the chorion
- Becomes the Corpus Luteum of Pregnancy
- Maintains uterine lining until placenta takes over as main producer of progesterone at 3 months
