Basics To Master Human Physiology For Mdcat 2022

Human physiology consists of about 11 organ systems. In order to master these systems, one needs to have a grip on the basic terminology used in this portion. In this article, we will try to master these basic terms. This will help you to understand and master Human physiology for the upcoming Mdcat.

Anatomical position: 

                                                      Whenever one compares the location of different body parts one must imagine it according to the standard anatomic position which is the scientifically agreed-upon posture of the body as shown in the diagram.
  • Body erect facing forward
  • Feet slightly apart and parallel
  • Palms facing forward with arms by sides
  • Thumbs point away from the body
Keeping in mind this position we can accurately describe body parts and their relative positions. The terms used to do so are:

1. Superior and inferior:  Superior means lies above whereas inferior means lies below. These terms are used to locate whether a body part lies above or below another part of the body.

Examples: 

  • The head is superior(lies above) to the neck
  • The thorax is inferior(lies below) to the neck
  • The esophagus is superior to the stomach
  • The small intestine is inferior to the stomach

2. Anterior and posterior: Anterior refers to the front or direction toward the front of the body and posterior refers to the back or direction toward the back of the body. These terms are used to compare whether a body part lies in front of another body part or behind it.

Examples:

  • The trachea is anterior(toward the front) to the esophagus
  • The esophagus is posterior(lies behind) to the trachea

    From the image, it is clear that the trachea is towards the front or anterior and the esophagus is towards the back or posterior.

3. Dorsal and ventral: In humans due to bipedal locomotion(moving on two hind limbs) the dorsal and posterior means the same as they refer towards the vertebral column and in the same way ventral and anterior means the same as they refer towards the front or sternal side. In quadrupedal(walking on four legs) animals however the anterior and ventral do not mean the same similarly posterior and dorsal also refers to different sides. This is because the vertebral column of quadrupedal animals is above and this upper side is said to be the dorsal side whereas the belly side facing the ground is the ventral side. The anterior side is towards the front or face and the posterior side is toward the tail.

Example: In the human body

  • The vertebral column is the dorsal most whereas the sternum and belly are the ventral most.
4. Medial and lateral: A midline is an imaginary line that passes through the center of the body. If a part of the body is medial it means it is close to the midline of the body with respect to another part. In the same way, if a body part is lateral it means it lies away from the midline of the body with respect to another body part.

Examples: Keeping in mind the anatomical position we can say that

  • The radius bone of the forearm is lateral to the ulna bone of the forearm.
  • The ulna bone of the forearm is medial to the radius bone.
  • The nose is medial to the ear.