Lecture 5 - Endogenous hormones I Flashcards
What is the endocrine system?
Referes to the collection of glands of an organism that secrete hormones directly into the circulatory system to be carried towards distant target organs
How does the endocrine system differ from the exocrine system?
Uses glands rather than ducts
How does it differ from the nervous system?
Endocrine reacts slower with longer lasting effects
What is an endocrine hormone?
When hormone enter general circulation and acts of target cells in another body part
What is an autocrine hormone?
When the hormone acts on the cell that produced it
What is a paracrine hormone?
When the hormone acts on the adjacent cells to it’s production cells
What is hormonal amplification?
Hormones that are only released after being triggered by the action of a different hormone
What is a steroid hormone?
- Made from cholesterol
- Diffuses through the cell membrane and attaches to receptor within the cell
- Testosterone, oestrogen, cortisol
What is a peptide hormone?
- Made from multiple amino acids
- Attaches to receptor on the cell membrane
- GH, IGF, Insulin
What is an amine hormone?
- Made from single amino acid
- Attaches to receptor on the cell membrane
- Adrenaline/Noradrenaline
How do steroid and non-steroid hormones differ in how they are released?
Steroid are released as soon as they are produced
Non-steroid released in advance and stored in vesicles for later release
Where is testosterone produced?
Testes/aovaries
Name 3 physiological functions of testosterone?
Control of growth
Sperm production
Sex drive
What hormones are secreted before resistance exercise?
Adrenaline and Noradrenaline
What hormones are secreted during resistance exercise?
Adrenaline
Noradrenaline
GH
Testosterone
What hormones are secreted after resistance exercise?
GH
IGF- 1
Testosterone
Insulin
Where does testosterone secretion begin?
Hypothalamus - gonanadotropin releasing hormone
Where is testosterone produced in males and how much?
95% in Leydig cells in the testes
5% by adrenals
Where is testosterone produced in females?
Ovaries and adrenals
What makes up for less testosterone in females?
Increased GH and IGF-1
How long does steriodogenesis take?
35 mins
What are males basal testosterone levels?
10-35 mol.L-1
Wha are females basal testosterone levels?
<3 mol.L-1
When is testosterone at it’s highest
Morning and night
What are the age differences in basal testosterone levels?
Less testosterone in older compared to younger people
What is the serum testosterone response to resistance training?
Increases
Are there sex differences in testosterone levels in response to resistance training?
Much more secretion in males than females
However, both do increase
How long following resistance training does it take of T to return to baseline?
1 hour
How can you manipulate resistance training to increase T?
Shorter rest periods
