Physiological stages and secondary sexual characteristics of a man's life and the principles of penile erection

> 55. **How ​​many stages are there in a man's life? What are the physiological characteristics of each stage?**

>

A man's life can be divided into the fetal period, infancy, childhood, and adolescence.

> There are seven stages: adulthood, middle age, and old age. But the most characteristic and variable stage is...

> The two periods of childhood and puberty.

>

Human development, from fetus to adulthood, is a continuous process lasting approximately 20 years.

The process of >. Although race, region, and era differ, a person's height and weight

The annual growth values ​​and growth curves for the length, circumference, and width of each part all show wavy patterns.

> Sexuality and distinct stages. The first stage is from birth to 10 years old, during which time, Chinese boys...

The average height is 135.3 cm, reaching 79.2% of an adult's height, and the average weight is 28.0 kg.

> kg, reaching 47.3% of adults. The second stage is from around 11 to 20 years old, this

During this period, height can increase by an average of 35.5 cm, and weight can increase by an average of 31.2 kg.

Throughout the entire growth and development stage, the growth rate of different parts of the human body is not equal.

> There are distinctions between morning and evening, fast and slow.

>

> The period of puberty (12-18 years old) marks the second decade of a person's life.

The onset of puberty in boys can occur as early as 10 years old or as late as 15 years old, with an average age of 11-12 years old.

The developmental changes occur in the testes, which mature over a period of more than three years.

About six months later, pubic hair appeared, and the testicles began to change. A year later, the body grew rapidly, and the pubic hair...

Penis growth. While it takes 3-4 years for a person to grow a significant amount of height, the penis develops fully in a shorter time.

About two years later. After a boy's sperm is produced, sometimes semen may leak from his urethra while he is sleeping.

This fluid, known as nocturnal emission or wet dream, can also occur while the person is awake.

This is called spermatorrhea. It is a reliable sign that a boy has reached puberty.

>

> After reaching puberty (18-25 years old), in addition to the maturation of the reproductive organs,

Other parts of the body also underwent significant changes. The most notable change was the possession of...

> What distinguishes men from women are their secondary sexual characteristics, namely male secondary sexual characteristics.

>

This secondary sexual characteristic is induced by male hormones in the body. It is mainly manifested as...

The body is strong and robust, with well-developed bones and muscles, broad shoulders, and strong, powerful upper elbows.

They have narrow hips, short arms, and relatively long lower limbs. Additionally, men with this feature often have facial hair, a prominent Adam's apple, and a strong voice.

His deep voice exuded a dignified masculine quality. This was due to the effects of androgens.

Teenage boys are more likely to develop acne than girls, but as long as they keep their faces clean...

With proper cleansing, acne will clear up on its own.

>

Between the ages of 25 and 40, one is in their prime. All of the body's physiological functions have reached their peak.

A person in peak condition, full of energy and stamina, and with rich experience, is ideal for building a career.

> The prime of life. Furthermore, men past middle age have generally enjoyed stable and healthy sexual function for many years.

Life helps maintain a stable and good mental state. Entering late middle age, also...

> That is, between the ages of 45 and 60, the body's internal systems are quietly and imperceptibly starting to function.

Significant changes occur, such as a decrease in functional brain cells and a decline in the heart's contractile function.

A decrease in blood output leads to a reduction in total lung capacity and vital capacity, which in turn affects immunity.

Decreased function, reduced sexual function, and other organs and systems will exhibit signs of aging.

The weakened state of the body leads to male menopause.

>

After the busy and stressful years of middle age, gray hairs begin to appear.

Wrinkles indicate that one has reached old age (over 60 years old), and the various organs of the body are affected.

> Reduced reproductive reserves, significant decline in reproductive function, weakened disease resistance, and bodily instability

Increased susceptibility to disease. This physiological characteristic is also a common feature of the elderly.

The reason why "illness is easily caused" is that as people age, they should pay attention to their diet and daily life, and maintain good health.

Maintain an optimistic attitude and participate in regular physical exercise to promote health and longevity.

>

> 56. **What are secondary sexual characteristics?**

>

Is a newborn baby a boy or a girl? The determination is based on the reproductive organs: [the presence of these organs is not specified].

A penis indicates a boy, and a vagina indicates a girl. Thus, the penis and vagina constitute sexual intercourse.

> Characteristics-features that differ between the sexes. Genital organs, which are formed at birth.

> Officials, also known as primary sexual characteristics or main sexual characteristics.

>

The "mutation" that occurs in boys only after they enter puberty, besides the development of their reproductive organs...

Beyond physical maturity, other parts of the body also undergo significant changes. From one

The mischievous and adorable little rascal has transformed into a robust man with a deep, resonant voice.

A real man not only has a beard and a prominent Adam's apple, but also broad shoulders.

Broad chest and strong limbs. These characteristics gradually develop starting in puberty.

> These are present from birth; they are male secondary sexual characteristics.

>

How exactly are secondary sexual characteristics formed? This mystery was only solved after the discovery of androgens.

It turns out that male secondary sexual characteristics are caused by the influence of male hormones.

> Produced by [the process]. At birth, an infant's testicles are only the size of a peanut; they enlarge to [a larger size] during early childhood.

> The size of a sparrow's egg; at this stage, the testicles do not produce sperm, only a small amount of androgens. By then...

During puberty, the testicles enlarge to the size of a pigeon egg and begin to produce and secrete sperm.

A large amount of androgens are produced, and under the influence of androgens, male secondary sexual characteristics appear.

>

Male secondary sexual characteristics have three prominent features:

>

(1) The production of body hair (beard, armpit hair, pubic hair), especially on the genitals.

The growth of pubic hair can be seen as the beginning of male sexual maturity. Generally, the growth of pubic hair...

Currently, as early as around 12 to 13 years old, a small amount of [something] can be seen on both sides of the base of the penis.

The hairs are light in color and fine. They gradually spread towards the perineum, and their color gradually...

The hair turns darker, becomes coarser and curlier. In late puberty, the inner thighs and pubic symphysis area...

Pubic hair also appeared. Armpit hair appears about a year later than pubic hair, usually starting from the armpit.

The hair begins to spread from the central area outwards. Beard growth typically begins around age 15.

It starts growing from the sides of the upper lip and gradually moves towards the center, later extending to the temples and chin.

> It appears that some people's beards will grow to a certain length and then connect, forming a full beard.

>

(2) Voice change: the voice changes from high-pitched to low-pitched, and the Adam's apple protrudes in the middle of the neck.

>

(3) The enlargement of the testes and penis, the secretion of semen and even the occurrence of nocturnal emission indicate that the boy has entered puberty.

>

> 57. **How ​​does the penis become erect?**

>

The penis is composed of three corpora cavernosa, which are surrounded by skin and fascia.

In cross-section, the two corpora cavernosa are located parallel to each other on the dorsal side of the penis, one urinary tract...

The corpora cavernosa are located on the ventral side (through which the urethra passes), arranged in an inverted "品" shape.

> Column. All three corpora cavernosa are surrounded by dense fascial tissue-the tunica albuginea-forming three...

> An independent column of spongy tissue. The spongy tissue contains numerous small trabeculae composed of connective tissue.

The trabeculae form a network, with gaps in the network called cavernous sinuses; the cavernous sinuses are interconnected.

It communicates with arteries and veins; therefore, the cavernous sinus is actually a blood sinus that can store blood.

The walls of the penile arteries and veins have numerous ridges protruding into the lumen; these ridges...

It's about controlling the valves for penile erection and flaccidity. When the penis is at rest, movement...

> The erythrocyte ridge constricts, the lumen of the artery narrows, while the shortcut between the artery and vein opens, allowing the artery to...

Blood enters the veins directly via a shortcut, with only a small amount of blood flowing through the corpora cavernosa.

The blood sinuses are located in the area where the penis is flaccid. When the penis is erect, the arteries dilate, and...

The shortcut between the arteries and veins constricts, causing a large influx of arterial blood into the corpora cavernosa.

Within the blood sinuses, congestion and dilation compress the small veins in the trabeculae, preventing blood from flowing out.

The blood returns to the body, causing the corpora cavernosa to become significantly engorged and swollen, resulting in penile erection. Sexual arousal.

Afterwards, the arterial crest constricts, the arterial lumen narrows, while the venules dilate, and the blood sinuses...

Blood returns from the veins, and the penis returns to a flaccid state.

>

The rigidity of penile erection depends primarily on a sphincter muscle or ring within the prostate.

> Sphincter muscle band. Because the blood vessels flowing from the penis pass through this sphincter muscle, therefore...

Therefore, the tighter the sphincter muscles are compressed, the less blood flows out, and the harder the penis becomes when erect.

>

Erections can be caused by the sexual desire center in the cerebral cortex.

Erection is called psychogenic erection; another type depends on stimulation of the penis itself, called...

An erection occurs as a reflex. All types of erections originate from the erectile dysfunction centers located in the spinal cord.

The central nervous system issues "commands" via the autonomic nervous system (i.e., the sympathetic and parasympathetic nervous systems).

> These mechanisms are used to transmit and cancel "commands." A malfunction in any of these regulatory functions can lead to erectile dysfunction.

>

> 58. **Why is penile erection more likely in the morning?**

>

A normal male's penis will become erect only in response to sexual stimulation and certain external stimuli.

Externally, it is usually in a relaxed state. However, sometimes the reflexes of internal organs can also...

This leads to penile erection. The most obvious example is often a penile erection that occurs before waking up in the morning.

This phenomenon may be related to having erotic dreams or excessive bladder storage.

Excessive heat increases pressure within the bladder, creating a stimulating effect that can lead to penile erection.

This creates a subconscious, reflexive erection, often referred to as "holding in" urine until it becomes hard.

This is a normal physiological phenomenon, medically known as morning erection. However...

The intensity of this erection, whether great or small, never reaches the level unique to sexual intercourse.

>

According to research by an American scholar, after reaching adulthood, men aged 20-...

> At age 30, morning erections increased, gradually decreasing after middle age. A German...

The doctor also studied this physiological phenomenon and found that during illness, men... (The sentence is incomplete and lacks context).

The erection will disappear, and the morning erection will return once the body has recovered.

The phenomenon reappeared. Therefore, he proposed that morning penile erection could be used as a symptom for observation.

> One of the reference indicators for observing a man's energy and health status.

>

However, the exact mechanism of morning erections has not yet been fully understood.

Chu, in any case, morning erection is a normal physiological response in men.

It is absolutely certain, and the daily variations due to individual differences among men are also...

> It's crucial to be consistent; you absolutely cannot judge a man's sexual function solely based on this one point. Sincere

However, doctors need to use this as a reference when differentiating and diagnosing changes in sexual function.

This applies entirely to pathological conditions, and should not be applied blindly to a normal man.

This is how you can distinguish between good and bad. Some nephews experience a temporary cessation or relaxation of morning erections.

At that time, they suspected they had erectile dysfunction, and became increasingly worried.

If you have erectile dysfunction, you'll experience fewer morning erections, and they may even be weak and feeble. This is a type of...

A terrible vicious cycle: psychological anxiety leads to physical ill health.

> Complete; and physical ailments, in turn, trigger further psychological anxiety, and so on.

The condition is worsening. At this point, you should seek medical attention immediately.