Topics in BiologyHindbrain: Medulla Oblongata and its features Food web explained with examples Biology Scheme of Work, SS1, First Term Biology Scheme of Work, SS1, 2nd Term Biology Scheme of Work, SS1, 3rd Term Seminal Vesicles and Bulbourethral Glands as Male Accessory Sex Organs Male Reproductive System: Scrotum and its contents Brain: Introduction to the Human Brain Forebrain: Lobes of the Cerebrum and their Functions Cerebellum: Parts and Functions of the Cerebellum Midbrain: Division and Functions of the Midbrain Negative Feedback Mechanism in Homeostasis Arterial Disorders: Characteristics and Causes of Arterial Disorders Types of Desert and their Characteristics Characteristics of Tropical Rainforest Swamp Forest: What are Swamp Forests? Characteristics of Swamp Forests Savanna: Savanna and Grassland explained Savanna - Types of Savanna Tropical Savanna and Temperate Savanna with their Characteristics
Academic Questions in Biology
Cold blooded animals are referred to as _____.
F. None of the above
All reptiles are vertebrates.
_____ cells are responsible for the formation of osteoblasts.
_____ is a bone that constitute the axial skeleton.
Which of the following is false concerning cartilages and bones?
A diagram showing the movement of energy through a food chain is called a _____.
Which of the following is NOT a part of the wrist bones (or carpal bones)?
The statements below are true concerning arteries except _____.
A. The arterial wall has 4 layers
B. Tunica Adventitia is the outermost layer of an artery
C. Aorta is the largest artery in the human body
D. Pulmunary artery conveys deoxygenated blood
E. Internal bleeding will occur when a deeply located artery is broken
F. Arterial vascular disorders are worsened in people with diabetes and renal failure
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The scrotum (or scrotal sac) is visible on every male as it lies underneath the penis, hanging from the midline of the pelvic region just between both thighs. It is a part of the external male genitalia.
Inside the scrotal sac are two oval shaped testicles or testes (singular -> 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 its midline by the perineal raphe.
The perineal raphe is present in males and females. It is visible as a midline seen on some parts of the human body.
The image below shows the scrotum, perineal raphe and the internal contents of the scrotum:
The scrotum is located outside the body and that's ideal. This is so because the testis requires a temperature slightly lower than that of the normal body temperature (36.5oC) to properly form sperms. In fact, this is the very reason why the testes descends from the abdominal cavity (inside the body) to the scrotum (outside the body). This external position of scrotum therefore presents a temperature reduced by -1oC to -7oC.
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 cremaster muscles of the scrotum have got a great ability to contract and relax, thus aiding the testes to either move closer to the body or away from it; depending on the surrounding temperature.
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 refers to the thick whitish (or slightly yellowish) and viscous fluid released from the penis. This process of releasing semen in males is termed ejaculation.
Ejaculation is always accompanied with a characteristic feeling of pleasure. In fact, this pleasurable feeling is the climax of sexual excitement and it's referred to as orgasm.
Note: The sperm cells are actually present within the semen. This is shown in the image below:
In summary, we can say that the semen contains the following:
Note: Apart from the sperm cells, many of these components (of the semen) are secretions from the male accessory reproductive glands.
Apart from the testicles, also found in the scrotum are:
The epididymis is a comma-shaped highly convoluted or coiled tubule of about 6 to 7 meters in length. It can be seen on the superior, lateral and posterior sides of each testis.
The epididymis is divided into 3 parts. These are:
The epididymis generally serves the following functions:
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 of the spermatic cord below).
Note: The contraction of the smooth muscles of the vas deferens helps in propelling the sperm during ejaculation. Also, 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.
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:
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 while its nerves assist in transferring information back and forth from the scrotum, testicles and the cremaster muscles.
They help in the movement of the testicles towards and away from the body in order to achieve an ideal temperature for sperm formation.
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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.
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Amazing facts in Biology
Armadillos are western mammals known for their unique armor-like shell which are bulletproof
Although 🦓 zebras 🦓 are known for their characteristics black and white stripes, we still have some polka-dotted zebras
Charles Darwin is a British naturalist and biologist who contributed greatly into the study of evolution. According to research, he frequently ate the animals he studied
Lungs are the only human organ that can float on water
Unlike most 🐍 snakes 🐍 that lay eggs, anacondas give birth to live babies
A 🦐 shrimp's 🦐 heart is in its head
Women have more pain receptors than men
It's crucial you finish your antibiotics.
If you stop taking your antibiotics before you're supposed to, any bacteria that didn't get killed can develop an immunity to that antibiotic and become a super-strain, making it much difficult to kill in the future. So keep taking your antibiotics pill, even if you feel better.
Although rare, women can still give birth when they die. This is known as coffin birth
Men can actually get aroused post moterm. This is called priapism
NOTABLE POINTS IN Biology
For a thing to be considered Living, it must possess all the Basic Characteristics of Life. These include:
Irritability or Sensitivity
During strenuous exercises like sprinting or 🏃 running, your body may actually work in the shortage of oxygen. During this time, your body owes oxygen (called oxygen debt) and it must be replenished or repayed after the exercise is stopped. This is why you breathe excess of oxygen after you stopped the exercise.
This is the concept of anaerobic respiration
A food Chain is a diagram that shows the relationship between plants and animals within a habitat on the basis of how they rely on each other for food.
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.
Note: Plants are the only orgnisms that take away CO2 from the atmosphere