Activity 3
EXERCISES
by GEORGETTE E. ZALDIVAR
Watch this video to view a rotating and exploded skull with color-coded bones. The link of the video at the study guide.
- Which bone (yellow) is centrally located and joins with most of the other bones of the skull?
The yellow-colored bone in the central part of the skull is called the sphenoid bone. It is referred to as one of the most complex bones of the human body. Its shape resembles that of a butterfly, and it also looks similar to the pelvic bone. It is also called the “wasp bone” due to its shape. The sphenoid bone is located in the central portion of the skull’s base and is a component of the middle cranial fossa’s foundation.
View another video to review the two processes that give rise to the bones of the skull and the body. The access of the video is in the study guide. Answer this question:
- What are the two mechanisms by which the bones of the body are formed and which bones are formed by each mechanism?
The two mechanisms by which the bones of the body are formed are intramembranous ossification and endochondral ossification.
> Intramembranous ossification occurs on or within the fibrous connective tissue membrane. This mechanism converts mesenchymal cells to bone, consequently forming the flat bones of the skull, clavicle, and most of the cranial bones.
> Endochondral ossification is when bone tissue takes shape in early fetal development. This mechanism involves the replacement of cartilage with bone. It is responsible for the formation of all long bones of the axial skeleton, like vertebrae and ribs, and the appendicular skeleton, like limbs.
Watch another video (link at the study guide) to see an animation of synovial joints in action. Answer the following questions after watching the video.
- What are the synovial joints being described in the video?
The synovial joints described in the video are as follows:
> Ball-and-socket joint
> Hinge joint
> Pivot joint
> Condylar/Condyloid joint
> Saddle joint
> Gliding joint
- Which type of synovial joint allows for the widest ranges of motion?
The synovial joint that allows for the widest ranges of motion is the ball-and-socket joint. This synovial joint has rounded, ball-like ends on one bone that fit into sockets that resemble cups on other bones, allowing for the most comprehensive ranges of motion, as movements in all directions are made possible.
REFERENCES:
Cork, A. (2011). Synovial Joints. Retrieved from YouTube: https://www.youtube.com/watch?v=VNbrvU7MgY0
Kabi. (2012). Skeletal System: Bone Formation (Intramembranous Ossification & Endochondral Ossification). Retrieved from YouTube: https://www.youtube.com/watch?v=p-3PuLXp9Wg
WitmerLab. (2011). Human skull - exploded skull with bones labelled, based on CT scanning. Retrieved from YouTube: https://www.youtube.com/watch?v=FrpVzSK23Q0