Topics in BiologyMale Reproductive System: External and Internal Male Genitals Male accessory sex organs Food Chain, Food Web and Food Pyramid Skeleton, Type of Skeletal Materials and Differences between Cartilages and Bones Bones - Types of Bone Bones and Type of Bone part 2 Red Blood Cells and Hemoglobin Tropical Rainforest and Savanna with their characteristics Desert and Swamp Forest - Types of Desert, Characteristics of Deserts and Swamps Plant Nutrition and Photosynthesis - Autotrophic mode of Nutrition Amazing facts in Biology Protists - Examples and Characteristics of Protists Reptiles - Characteristics of Reptiles Homeostasis and Negative Feedback Mechanism Arteries, Layers of an Artery and Characteristics of Arterial Disorders Introduction to Biology - Basic Characteristics of Life
Academic Questions in Biology
Which of the following is a category of long bones?
The end product of photosynthesis is _____.
The above diagram illustrates a _____.
The living cells that makes up cartilages are called _____.
Which of the following statement is incorrect with regards to chitin?
Which of the following is NOT a function of the human skeleton?
Organisms that manufacture their own food through the help of sunlight or chemicals are best referred to as _____.
Organisms that begins a food chain and also manufacture their food through photosynthesis are best referred to as _____.
Reproduction is one of the basic characteristics of life. All living organisms have the ability to give birth to offspring (young of the same kind).
Reproduction can be defined as the process through which organisms give birth to their young (offspring) of the same kind.
Reproduction can be put into two types. These are:
- Sexual Reproduction
- Asexual Reproduction
In this article, we will focus our attention on the male reproductive system which is a requirement for sexual reproduction.
The male reproductive system consists of organs (called genitals) that are present both externally and internally.
Reproductive organs present on the outside of the body are generally referred to as external genitalia while those present inside the body are termed internal genitalia.
The Male External Genitalia include the followings:
The Male Internal Genitalia include the followings:
- Vas Deferens
- Ejaculatory Duct
- Seminal Vesicles
- Prostate Gland
- Bulbourethral Glands or Cowper’s Gland
Note: The seminal vesicles, prostate gland, bulbourethral glands (Cowper’s glands) are often referred to as accessory organs of reproduction in males.
Please read on the Male Accessory Sex Organs here. (It will give you a better understanding on the explanations below, especially with those relating to Semen).
The penis is the copulatory and intromittent organ required for the male sexual act. It is the ideal organ for introducing sperm into the female’s vagina through a process called ejaculation.
Note: For ejaculation to occur, orgasm has to take place.
Orgasm is a series of contraction of the muscles present within the penis which ultimately lead to the release of semen.
This process of ejaculation is the climax of the male sexual act.
Below is a diagram of the Penis and its divisions:
Image Credit: Teach Me Anatomy
Anatomically or structurally, the penis can be divided into three parts. These are:
1. Root of the Penis: This is the fixed part of the penis and it’s located within a male's body.
Note: The penis actually begins from inside the body, directly below the bulbourethral organs at the pelvic floor.
The root of the penis is made up of two kinds of muscle. These are:
- Ischiocavernosus Muscle: It helps to produce and maintain erection.
- Bulbospongiosus Muscle: It assists in the forceful expulsion of semen from the urethra.
2. Body of the Penis: The penile body marks the beginning of the visible part of the penis as it extends from the root to the glans penis.
It is made up of three cylinders of erectile tissues which are two corpora cavernosa and one corpus spongiosum.
Image Credit: Arizona Center for Advanced Medicine
Note: Erection of the penis is a vascular process; that is, it results from the flow of blood into the corpora cavernosa and corpus spongiosum muscles respectively.
Lack of adequate blood flow to the penis will result to little or no erection. This condition is medically termed Erectile Dysfunction (ED) or Impotence.
The erectile tissues are highly vascular; that is, they can receive a good amount of blood supply. As a result, they play a significant part in the erection of the penis.
3. Glans of the Penis: Fondly called the glans penis, it is the expanded and rounded head of the penis.
The Glans penis contains an opening (called urethra) around its center.
At birth, the glans is covered by a fold of foreskin called the prepuce. This foreskin is connected by a soft tissue (called the frenulum) to the neck of the glans.
Often times, the foreskin is removed at birth through a process called circumcision. Parents who do not circumcise their children should clean their glans penis daily so as to prevent bacteria growth around that region.
The glans contains numerous touch receptors and as a result; it can be very sensitive to touch.
Note: Urine and Semen are released from the external urethral orifice; that is; the opening present at the tip of the glans.
The scrotum or scrotal sacs are visible on every male as it hangs from the body (pelvic region) just between both thighs.
Inside the scrotal sacs are two oval shaped testicles or testes (singular is testis) which are responsible for the formation and storage of sperm.
The process of sperm formation is referred to as spermatogenesis.
Note: The scrotum is divided in the midline by the perineal raphe.
The perineal raphe is present both in males and females. It is a visible midline on some parts of the human body.
The image below shows the Scrotum, Perineal Raphe and the internal contents of the Scrotum:
Image Credit: Teach Me Anatomy
The scrotum is ideally located outside the body because the formation of sperm requires a temperature slightly lower than that of the body. (About 1o – 7oC lower than the body’s 36.5oC).
Sperm is produced by the testes residing within the scrotum; and the surrounding temperature is extremely important for it's formation. To this end, the scrotal muscles have got a great ability to contract and relax which aids the testes to either move closer to the body or away from it; depending on the surrounding temperature.
As a male, one may have observed that on cold days, the scrotum hangs towards the body. Conversely, it tends to move downwards (away from the body) on warmer days.
Apart from the testicles, also found in the scrotum are:
1. Epididymis: This is a highly convoluted or coiled tubule of about 6 to 7 meters in length. It serves the following functions:
(A) The epididymis stores sperm for about 80 days, bringing them to maturity.
(B) It also improves sperm motility by absorbing some of the fluids produced by the testicles during sperm formation.
(C) The epididymis also protects the sperm cells.
The epididymis leads into another tubule called the vas deferens. (Please see the diagrams above and below).
2. Spermatic Cord: This is a cord-like structure formed by the vas deferens. It plays an important role in the supply of blood to the testes and vas deferens. It also aids the movement of sperm out of the epididymis into the ejaculatory ducts.
Below is an image showing the contents of the Spermatic Cord:
Image Credit: Vasectomy Information
Note:The spermatic cord contains a large amount of blood vessels and nerves.
The blood vessels supply blood to the testes, epididymis and cremaster muscles.
Its nerves assist in transferring information back and forth from the scrotum, testicles and the cremaster muscles.
3. Cremaster Muscles: They help in the movement of the testicles towards and away from the body in order to achieve the ideal temperature for sperm formation.
Note Sperm and Semen is not the same thing.
Sperm is the male sex cell (and it happens to be the smallest cell in the human body). It is exactly what meets and fertilizes the female sex cell (ova or egg which is the biggest cell in the human body).
Millions of sperm cells are always introduced into the female’s vagina during ejaculation; and they swim upwards (towards the oviduct or fallopian tube in the female) with the aid of their tail-like structure called flagella.
Semen on the other hand refers to the thick whitish (or slightly yellowish) and viscous fluid released from the penis during orgasm.
The sperm cells are actually present within the semen.
In summary, we can say that the semen contains the following:
- The sperm cells
- Amino Acids
- Vitamin C
- Zinc prostate specific antigen
- Silic Acid
Note: Apart from the sperm cells, many of these components (of the semen) are secretions from the male accessory reproductive glands.
4. Vas Deferens: The vas deferens is found both within and above the scrotum. It is a long muscular tube that begins at the tail of the epididymis and runs through into the ejaculatory ducts. (Please see the diagram above).
Note: The contraction of the smooth muscles of the vas deferens helps in propelling the sperm during ejaculation.
As sperm move from the vas deferens into the urethra, secretions are added to it from the male accessory sex glands.
The vas deferens is also called the ductus deferens.
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Alfred Ajibola is a Medical Biochemist, a passionate Academician with over 7 years of experience, a Versatile Writer, a Web Developer, a Cisco Certified Network Associate and a Cisco CyberOps Associate.
Amazing facts in Biology
Male Seahorses actually give birth to their young ones, NOT the female
All babies are born with blue eyes
Research made at the University of Vienna suggested that yawning may play an essential role in cooling the brains
All voluntary and concious activity of right handed people are controlled from the left part or hemisphere of the brain
A snail can actually sleep for 3 years 😁
An adult human being is composed of about 60% water. In fact, a newly born baby is composed of about 80% of water. This will drop to 65% after a year and finally to about 60% as the child ages
Without saliva, food can never be enjoyed. Food becomes tasteless since saliva is needed to dissolve the chemicals present in food onto the tongue’s taste buds.
Saliva also contains an enzyme called salivary amylase or "ptyalin" which helps to digest cooked starch to maltose. Maltose is a double sugar or disaccharide. Please read on sugars here
NOTABLE POINTS IN Biology
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This is the concept of anaerobic respiration
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Note: Habitat is a place where an organism live. It is of three types:
The term Biology originated from two Greek words. They are:
Biology can therefore be defined is the study of life
Anything that has life is generally considered as a living organism (or organism) 🌱🐐🐓. All living organisms must be able to carry the following activities:
The above listed points are often regarded as the basic characteristics of life. You can memorize them using the acronym (MR. NIGER DAC).
The gas used in the manufacture of food by plants is Carbon dioxide or Carbon(IV)oxide or CO2.
Plants manufacture food through a process called photosynthesis. Please read on photosynthesis here
Note: Plants are the only orgnisms that take away CO2 from the atmosphere
In the Biological organization of life, it is said that cells form tissues, tissues form organs and organs form systems. There are 12 systems in the human body; these are: