Week 2 - Sexological Male Anatomy & Physiology Flashcards
Sexual health: a predictor of general health and longevity
Physical health is significantly correlated with sexual activity and many aspects of sexual function, irrespective of age
Sexual activity is inversely related to mortality; in one cohort study, mortality risk was 50% lower in men with high frequency of orgasm than in men with low frequency of orgasm
Context
- Religion
- Culture
- Communication
- Relationship
Mind
- Self-image
- Body image
- Cognitions
- Thoughts
- Depression
- Fear
Body
- Age
- Condition
- Disease
- Medication
- Life Style
What determines the presence of testes or ovaries
The presence or absence of SRY gene
SRY –> testes otherwise ovaries
When do testes develop?
The 7th week outer portions of gonads degenerate and inner portions develop into testes
When do ovaries develop?
11th week the inner portions of gonads degenerate and outer portions develop into ovaries
What do the endocrine glands produce
Male hormones (androgens)
Mullerian inhibiting substance
When does puberty occur?
When hypothalamus begins to secrete gonadotropin-releasing hormones (GnRH) causing pituitary to release:
- Follicle-stimulating hormone (FSH
- Luteinizing hormone (LH
Limbic system
Important for controlling behavior for survival (eating, emotions, fighting, flight, reproduction)
Hypothalamus
Important for several things, such as hunger and thirst, circadian rhythm and sex.
Genital reaction
Core regions in the hypothalamus project directly or
via core regions in the brainstem into autonomous
neurons in the spinal cord
The software of sex drive
The role of neurotransmitters
The hardware of sex drive
How neurons and neuronal networks process and modulate sexual responses
Neurotransmitters
- Noradrenaline / adrenaline –> fight/flight
- Cortisol –> stress
- Testosterone –> motivator
- Dopamine –> pleasure, well-being
- Serotonin –> obsession
- Oxytocin –> bonding, attraction, arousal
Excitatory factors
- Testosterone
- Estrogen
- Progesterone
- Dopamine
Inhibitory factors
- Serotonin
- Prolactin
- Opioids
Average penis
- 12.9 - 13.9cm erect
- 9.16cm stretched
- 8.7cm flacid
Micropenis
- <4cm flaccid and <7.5cm erect
Phases of erection
- flaccid phase
- latent phase
- tumescent phase
- full erection phase
- rigid erection phase
- detumescence phase
Flaccid phase
Cavernosal smooth ms contracted; sinusoids empty; minimal arterial flow
Latent phase
Increased pudent artery flow; erection forming
Tumescent phase
Rising intracavernosal pressure; erection forming
Full erection phase
Increased cavernosal pressure causes penis to become full erect
Rigid erection phase
Further increases in pressure + ischiocavernosal muscle contraction
Detumescence phase
Following ejaculation, sympathetic discharge resumes; there is smooth muscle contraction and vasonstriction; reduced arterial flow; blood is expelled from sinusoidal spaces
Erection types
- Psychogenic erections
- Reflexogenic erections
- Nocturnal erections
Mechanisms of erection
- Erotic stimuli (dopamine)
- Neural initiation: parasymp. oxytogenic nerve fibers
- Cellular activation of L-arginine pathway
- Relaxation of cavernous smooth musculature
- Erection
Peripheral neuroanatomy
- Parasympathetic pathways (sacral nerves 2- 4)
for control of erection - Sympathetic pathways (thoracic T10–L2)
control detumescence and ejaculation - Both pass to the Cavernosal nerve
Somatic neuroanatomy
- From S2-4 Onuf’s nucleus to the Pudendal and
Dorsal nerves - Innervate the bulbocaversus muscles (pelvic floor)
Erection enemies
- Smoking
- Alcohol
- Drugs
- Stress
- Anxiety
The deadly quartet
- Diabetes
- Obesity
- Hypertension
- Dislipidemia
Functions of pelvic floor
- Innervate the bulbocaversus muscles (pelvic floor)
- The pelvic floor is part of the sphincters mechanism of the anus and urethra (is essential for continence).
- The pelvic floor of women is important in the birth process because of the resistance in the birth canal that is essential for the spindle rotation.
Support
Passage
Mobility/stability
Sex
Emotion
Involvement of PF
- Enhancement of blood flow
ischiocavernous muscle facilitates
erection - bulbocavernous maintaining the
erection (pressing deep dorsal
vein) - Inhibit ejaculation relaxation of the bulbocavernous
and ischiocavernous muscles
