Male Phys Flashcards
1
Q
describe the secretion of GnRH
A
- released in median eminence of hypothalamus
- secreted for a few minutes every 1-3 hours
2
Q
describe the cell signaling pathway of GnRH
A
- IP3 and DAG increases Ca which causes exocytosis of LH/FSH
3
Q
describe the cell signaling pathway of LH
A
- binds to Leydig cells receptors to increase cAMP
- increases DNA transcription to produce testosterone from cholesterol
4
Q
describe the cell signaling of FSH
A
- binds to Sertoli cells receptors to increase cAMP
- causes increase in DNA transcription of:
- inhibin
- aromatase
- androgen binding protein
- GFs
5
Q
describe the function of ABP
A
- helps maintain high levels of local concentrations of testosterone to help keep sperm viable
6
Q
describe the cell signaling pathway of testosterone
A
- binds to intracellular receptor (it’s a steroid)
- testosterone is converted into DHT (via 5 alpha reductase)
- DHT binds to receptor and causes modulation of gene expression
7
Q
describe the function of testosterone in the fetus
A
- forms penis and scrotum
- accessory organs
- testicular descent
- female suppression
- if testosterone levels low, female genitalia may be present
8
Q
describe the function of testosterone in adults
A
- promotes long bone fusion
- increases BMR
- increase in RBC mass
9
Q
describe the secondary sexual characteristics caused by testosterone in adult males
A
- deposition of protein
- increase in muscle mass
- increase in strength and size of bones
10
Q
how does testosterone travel and how is it metabolized
A
- travels bound (~97%) to:
- sex-hormone binding globulin
- albumin
- free testosterone is coverted into the more active form by 5-alpha reductase into DHT
- it is broken down in the liver and excreted by the kidneys
11
Q
describe feedback mechanisms of LH and FSH
A
12
Q
describe the formation of the ejaculate
A
13
Q
describe the mechanism of an erection
A
14
Q
A
15
Q
A
