When a guy is turned on, a series of physiological changes occur in his body.
These changes prepare him for sexual activity and are governed by the nervous and endocrine systems. Here's a more detailed breakdown:
- Increased Blood Flow: The primary physical change is increased blood flow to the penis. This engorgement of blood fills the spongy tissues within the penis (corpora cavernosa and corpus spongiosum), leading to an erection.
- Erection Development: The penis becomes rigid and erect due to this increased blood flow and pressure.
- Testicle Changes: The testicles may rise closer to the body.
- Perineum Sensation: A warm sensation can develop in the perineum, the area between the testicles and the anus.
- Heart Rate and Blood Pressure Increase: The cardiovascular system responds with an elevated heart rate and increased blood pressure.
- Breathing Rate Increase: Breathing becomes faster and sometimes deeper.
- Muscle Tension: Muscles throughout the body, particularly in the thighs and buttocks, may tense up.
- Nipple Sensitivity: Some men experience increased sensitivity in their nipples.
- Skin Flushing: Skin may become flushed in certain areas, like the face and neck.
- Psychological Changes: Alongside the physical changes, there are psychological responses. These can include heightened senses, increased focus, and feelings of excitement and anticipation.
As arousal continues and intensifies, these changes become more pronounced, leading toward orgasm. The referenced answer notes that as a guy gets closer to orgasm, the physiological effects increase.