Endocrine response to resistance training Flashcards
Define endocrine
When the hormone enters general circulation and acts on target cells in another body part
Define endocrine system
The collection of glands of an organism that secrete hormones directly into the circulatory system to be carried towards a distant target organ.
Define hormones
A regulatory substance produced in an organism and transported in biological tissue and /or fluids to stimulate specific cell/tissue types into a specific action
Define autocrine
When the hormone acts on the cell that produced it
Define paracrine
When the hormone acts on the adjacent cells to the production cells.
Some hormones are released only after being triggered by the action of a different hormone. Cortisol is an example of this. How is cortisol released?
The hypothalamus produces corticotropin releasing hormone (CRH) to the pituitary gland.
Pituitary gland produces ACTH which stimulates the adrenal gland to produce cortisol.
What helps control the pituitary’s production of ACTH?
Cortisol levels in the adrenal gland
What are the 3 types of hormones and what are they made of?
Steroid - cholestral
Peptide - proteins
Amine - proteins
How do steroidal hormones work?
- Steroid hormone enters cell
- Binds to specific receptor in the cytoplasm or nucleus
- Hormone-receptor complex activates the cells DNA forming mRNA
- mRNA leaves nucleus
- mRNA directs protein synthesis in the cytoplasm
How do non-steroidal hormones work?
- The hormone binds to a specific receptor on the cell membrane (can’t pass through membrane)
- This activates adenylate cyclase within the cell and forms cAMP
- The cAMP activates protein kinases that lead to cellular changes and hormonal effects.
What is the difference in the release of steroid hormones and peptides and amines?
Steroid - released as soon as produced
Peptides/amines - produced in advance and stored in vesicles for later release
How does hormonal action interact with the lock and key theory?
Transport hormones, deliver hormone to receptor and protect from early metabolism
List 2 systematic changes in hormone delivery with exercise?
- Fluid volume shifts
- Blood flow re-distribution during exercise - greater amount of hormones to working muscles
How does an increased cardiac output effect hormone delivery?
Clearance of hormones through other tissues allows quicker delivery to muscle tissue.
Which hormones have a response before resistance exercise?
Adrenaline
Noradrenaline
Which hormones have a response during resistance exercise?
Adrenaline
Noradrenaline
Growth hormone
Testosterone
Which hormones have a response after exercise?
Growth hormone
Testosterone
IGF-1
Insulin
Where do males produce 95% of testosterone? and 5% of it?
95% from Leydig cells in testes
5% from adrenals
Where do females produce lower concentration of testosterone from?
Ovaries and adrenals
How long does steroidogenisis take?q
35 minutes
How does testosterone work?
- passively diffuses across sarcolemma of a muscle fibre
- Binds with its receptor to form a hormone receptor complex (H-RC)
- H-RC arrives at genetic material in the cells nucleus and opens to expose transriptional units.
What are the basal testosterone levels of males and females?
Males = 10-35 nmol.l Females = <3.5 nmol.l
What happens to serum testosterone with acute exercise?
It increases
What are the 3 acute effect of testosterone on muscle tissue?
- Stimulates production of neurotransmitters
- Facilitates calcium release
- Increases protein synthesis
