Biology

Midbrain: Division and functions of the midbrain

len Alfred Ajibola - Thu, 06th February, 2020 @ 2:24 PM

Topics in Biology

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Academic Questions in Biology

Please click here to see all Questions and Answers

Male Reproductive System - Len Academy

From the above diagram, which of the organ below isn't a requirement for the male reproductive system?

  • A. Bladder

  • B. Ureter

  • C. Glans Penis

  • D. Testis

  • E. Bulbourethral Gland

  • F. Epididymis

A walnut shaped male accessory sex organ located between the bladder and penis is the _____.

  • A. Ductus Ejaculatorii

  • B. Bulbourethral Gland

  • C. Prostate Gland

  • D. Ductus Deferens

  • E. Seminal Vesicles

  • F. Epididymis

In a food chain, the primary consumers are classified under trophic level  _____.

  • A. Zero

  • B. One

  • C. Two

  • D. Three

  • E. Four

  • F. Five

Cold blooded animals are referred to as _____.

  • A. Homeotherms

  • B. Endotherms

  • C. Poilokitherms

  • D. Ectotherms

  • E. Thermotherms

  • F. None of the above

All reptiles are vertebrates.

  • A. True

  • B. False

_____ cells are responsible for the formation of osteoblasts.

  • A. Osteocytes
  • B. Chondrocytes
  • C. Chondroblasts
  • D. Osteoclasts
  • E. Osteoprogenitor cells
  • F. Osteoblastic

_____ is a bone that constitute the axial skeleton.

  • A. Clavicle
  • B. Scapula
  • C. Patella
  • D. Radius
  • E. Sternum
  • F. Femur

Which of the following is false concerning cartilages and bones?

  • A. Cartilage does not have a direct blood supply while bones have direct blood supply
  • B. The process of ossification replaces a cartilage to bone
  • C. The protein that makes up cartilage is called chondrin while that that makes up bone is called ossein
  • D. Cartilage grows from both ends while bones grow from one of its epiphysis
  • E. They both have living cells within them
  • F. Haversian system is absent in cartilage but present in bones



Midbrain:

The midbrain, also referred to as the mesencephalon, is a division of the brain alongside the forebrain and hindbrain. It connects the forebrain to the hindbrain.

Please read on the forebrain here.

Present within the midbrain are various nuclei, nerves and tracts, each with an array of functions. In addition, visibly present on the midbrain are 4 bumps or swellings on its posterior surface. These are referred to as colliculi, and are made up of aggregated neurons.


The colliculi are separated into two pairs. These are:

  1. The upper pairs known as the superior colliculi. Functionally, they direct the reactions of animals towards environmental stimuli.
    You can read on irritability here.
  2. The lower pairs known as the inferior colliculi. Functionally, they are connected with hearing.

The image below shows the midbrain's colliculi:
Midbrain - Len Academy

Please read on the cerebellum here.


Divisions of the midbrain

The midbrain is divided into 3 parts. These are:

  1. Tectum: The colliculi are present on the tectum. They are shown in the diagram above.

  2. Tegmentum: The tegmentum (which means 'hood' in Latin) is a layer of the midbrain (and hindbrain) that runs down the length of the brainstem. It's various nervous connections has shown to keep humans alert.

    The tegmentum consists of an iron-rich red nucleus (which appears pink in colour) and the 'periaqueductal grey' which is a composed mainly of grey matter.

    Functionally, the iron-rich red nucleus play a role in the body's coordination and movements. Also, the periaqueductal grey has proven to be important in the suppression of pain.
    You can read on the beauty of suffering here.


  3. Cerebral Pundicles: They are paired structures that extends from the cerebral hemispheres and unites (or converge) at a part of the hindbrain called pons. Both cerebral pundicles are separated anteriorly by an interpeduncular fossa before their convergence posteriorly. Please see the image above.
    Please read on an introduction to the human brain here.

Functions of the midbrain

Some of the important functions of the midbrain include:

  1. Movement of the eyes.

  2. It regulates the dilation of the pupil.

  3. It regulates sleep and wake cycles.

  4. It controls our attentions and behaviour through the regulation of dopamine production.
    You can read on the uniqueness of man here.

  5. It assists in the regulation of temperature.
    Please read on homeostasis here.

  6. It regulates muscular movements.
    Please read on all 206 bones of the human body here.

  7. It is an important part of the memory.

  8. It is important in the hearing process.

  9. It helps to control our responses to sight.

  10. It aids in arousal.
    Please read on the male reproductive system here.

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Amazing facts in Biology

Russia is home to the largest area of forest in our world with a land mass of 815 million hectares

Giant Squid - Len Academy

Giant squid lives deep in the ocean and they have the largest eyes in the world

The movements of the fingers are controlled by muscles of the palms and forehands

Platypus - Len Academy

Platypus (sometimes referred to as the duck-billed platypus) is an egg-laying, semiaquatic mammal found in eastern Australia. It has no stomach and as such, its food goes from the mouth through the esophagus and directly to their intestines.

Pufferfish - Len Academy

Pufferfish contain a toxin called tetrodotoxin. This makes them foul tasting and poisonous to predators. Tetrodotoxin is about 1,200 times more poisonous than cyanide, and there is enough toxin in one pufferfish to kill 30 adult humans. Unfortunately, there isn't any known antidote to this poison.

Interestingly, a delicacy in Japan (called fugu) is made from pufferfish. This meal is very expensive, and must be prepared by trained and licensed chefs. An improper preparation of fugu may lead to the customer's death. Sadly, such deaths are recorded annually

Wombat - Len Academy ​​​​​​

Wombats are the only animal with a cube-shaped poo. They can stack up these cube-shaped poo, marking their territory with it

Robert Waldow - Len Academy

Robert Wadlow (1918–1940) remains the tallest man ever recorded in the Guinness World Records. He was an American who stood at 8 feet, 11 inches.

An abnormally enlarged pituitary gland had resulted into Robert Wadlow's giant size.

Cockroach is the fastest land animal on six legs

Laughing ape - Len Academy

Like humans, all apes laugh when tickled

Ostrich eye and brain - Len Academy

An ostrich's eye is bigger than its brain


Notable points in Biology

Layers of an Artery - Len Academy

An artery is composed of three layers:

  • The outermost layer is termed tunica adventitia (or tunica external). It consist mainly of collagen fibres and connective tissues that anchors the arteries to other nearby tissues.

  • The middle layer is named tunica media. It is made up of smooth muscles and elastic fibres that supports the artery in conveying blood at high pressures.

  • The inner layer is called tunica intima (or tunica internal). It is lined by a smooth tissue called endothelium, and is made up of a fine network of connective tissues.

Please read on the layers of an artery here

All living organisms possess various features in order to survive in their environment. This is the concept of adaptation. As an instance, a fish is able to live in water because it has gills and fins.

Also, a camel is able to survive in the desert because it has large feet to aid walking on sand without sinking. It also has long eyelashes to help protect it from the blowing sand and wind.

Plants are also able to live in different habitats because they have the required adaptive features towards that habitat. For instance:

  • Plants that live in/on water are termed hydrophytes.

  • Plants that live on land with moderate amount of water are termed mesophytes.

  • Plants that live on deserts or arid lands are termed xerophytes.

The point is:

All organisms have various features on them that enables them adapt in their habitat

For a thing to be considered living, it must possess all the basic characteristics of life. These include:

  1. Movement

  2. Respiration

  3. Nutrition

  4. Irritability or Sensitivity

  5. Growth

  6. Excretion

  7. Reproduction

  8. Death

  9. Adaptation

  10. Competition

Please read the explanations on all the basic characteristics of life here

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

Food Chain - Len Academy

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:

  • Terrestrial (Land)
  • Aquatic (Water)
  • Arboreal (Treetops)

You can read on food chain here