Biology

Hindbrain: Medulla Oblongata and its features

len Alfred Ajibola - Sat, 17th October, 2020 @ 10:56 AM

Topics in Biology

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Academic Questions in Biology

Please check out our Test Your Knowledge page to see all Questions and Answers

Which of the following is NOT a part of the wrist bones (or carpal bones)?

  • A. Cuboid
  • B. Scaphoid
  • C. Hamate
  • D. Triquetral
  • E. Pisiform
  • F. Trapezium

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

The following statements are true concerning blood vessels except _____.

  • A. They are comprised of arteries, veins and capillaries

  • B. Problems associated with blood vessels are called vascular disorders

  • C. All veins carry blood towards the heart

  • D. Capillaries are found at cellular level

  • E. Arteries usually divide to form arterioles

  • F. Arterioles give rise to capillaries

Food Pyramid - Len Academy

The above diagram shows a _____.

  • A. Food Chain

  • B. Food Web

  • C. Food Flow

  • D. Food Energy

  • E. Food Pyramid

  • F. Food Hierarchy

Anything that elicits a physiological response from an organism is termed _____.

  • A. Response

  • B. Irritability

  • C. Adaptation

  • D. Competition

  • E. Stimulus

  • F. Action potential

Which of the following molecule is utilized directly as energy in the human body?

  • A. Glucose

  • B. Carbohydrate

  • C. Starch

  • D. Adenosine Mono Phosphate

  • E. Adenosine Di Phosphate 

  • F. Adenosine Tri Phosphate

Which of the following is not a basic characteristics of life?

  • A. Locomotion

  • B. Competition

  • C. Adaptation

  • D. Irritability

  • E. Nutrition

  • F. Death

The final organisms in a food chain are best referred to as _____.

  • A. Saprophytes

  • B. Parasites

  • C. Commensals

  • D. Decomposers

  • E. Tertiary consumers

  • F. Quatenary consumers

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Hindbrain (Medulla Oblongata):

The hindbrain, also referred to as rhombencephalon is one of the parts or divisions of the brain; the others being the forebrain and midbrain respectively.

Please read on an introduction to the Human Brain here.

The immediate processes of survival (for instance, respiration, blood circulation and digestive functions) are coordinated by the hindbrain, specifically the medulla oblongata; a part of the hindbrain.

Note: Other involuntary (or autonomic) processes ongoing in our body are also controlled by the medulla oblongata. Some of these include swallowing, digestion, vasodilation, vomiting, coughing and sneezing.

Please read on the uniqueness of man here.

The medulla oblongata (simply called the medulla) is seen at the lowermost portion of the brain (or brainstem) where it continues as the spinal cord inferiorly. For this reason, it becomes the primary point of connection between the Central Nervous System (CNS) and Peripheral Nervous System (PNS). 

Below is an image showing the Medulla Oblongata:
Medulla Oblongata - Len Academy

The medulla merges with the spinal cord at the foramen magnum. The foramen magnum is an opening located at the base of the skull, marking the beginning of the spinal cord. It is shown below:
Foramen Magnum - Len Academy

Superiorly, the medulla oblongata is connected to the midbrain via the pons. To this end, it plays a critical role in the transmission of nervous signals through the cerebrum (superiorly) and the spinal cord (inferiorly).

Please read more on the Forebrain and Cerebrum here.

The medulla comprises of both myelinated white matter and unmyelinated gray matter intermingled together, thus giving rise to a network of interconnected neuronal clusters within the brainstem.

You can attempt Len Academy questions on various subjects here.

The following anatomical features are keys to help us identity the medulla oblongata:
Medulla Oblongata - Len

  • Olive (Olivary body): The olivary body is a pair of oval structures present on the surface of the medulla oblongata. It contains numerous nerve fibers that connect the medulla to the pons and cerebellum respectively.

  • Median fissures (Midline Fissures): The median fissures are shallow grooves found on the anterior and posterior parts of the medulla. The posterior median fissure is referred to as the posterior median sulcus and it commences from the end of the fourth ventricle, continuing down into the sulcus of the spinal cord. The fissure (shallow grove) present on the anterior side is simply referred to as the median fissure. It is continuous with the median sulcus of the spinal cord.

  • Pyramids: These are two round masses of nerve fibers located on either side of the median fissure. They connect the medulla to the cerebrum, pons and spinal cord respectively. The pyramid are comprised of about one million nerves which crosses themselves in a process termed decussation of the pyramids.

You can read on the midbrain and its division here.

The medulla oblongata is divided into 2 main portions. These are:

The frontal portion (called the ventral medulla) which contains a pair of structures called pyramids (as explained above).

The backward portion is termed the dorsal medulla). It is this dorsal medulla that forms the dorsal region of the fourth ventricle.

Note: In anatomical terms, ventral means (in front or anterior) and dorsal means (rear or back or posterior).

Think of the fourth ventricle as a fluid filled space surrounded by white matter on the outside and gray matter on the inside.

The image below shows the fourth ventricle:
Fourth Ventricle - Len Academy

Recall that we have 12 cranial nerves exiting from the brain (and they connect to different parts of the body). It is noteworthy that the dorsal medulla gives origin to the last 7 seven cranial nerves. Below is a list of all the cranial nerves:

  1. Olfactory nerve
  2. Optic nerve
  3. Oculomotor nerve
  4. Trochlear nerve
  5. Trigeminal nerve
  6. Abducens nerve
  7. Facial nerve
  8. Vestibulocochlear nerve
  9. Glossopharyngeal nerve
  10. Vagus nerve
  11. Accessory nerve
  12. Hypoglossal nerve

You can read on Homeostasis here.

The medulla oblongata is vital for human survival. Injuries related to it may lead to the following:

  • Respiratory difficulties

  • Partial paralysis of the opposite side of the body

  • Partial paralysis to the tongue

  • Inability to feel the stimulus of touch, temperature and pain

  • Difficulty in vomiting and swallowing

  • Difficulty in coughing and sneezing 

Note: The cerebellum is another part of the hindbrain. It plays a major role in the body's voluntary movement (especially posture). It accounts for about 10% of the brain size and comprises of two cerebellar hemispheres separated by a structure called the vermis.

Please read more on the Cerebellum here.

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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

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

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

The term Biology originated from two Greek words. They are:

  • Bios: means life.
  • Logos: means knowledge or to study.

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:

  1. Movement
  2. Respiration
  3. Nutrition
  4. Irritability or Sensitivity
  5. Growth
  6. Excretion
  7. Reproduction
  8. Death
  9. Adaptation
  10. Competition

The above listed points are often regarded as the basic characteristics of life. You can memorize them using the acronym (MR. NIGER DAC).

You can read on the introduction to Biology and the basic characteristics of life here

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