Lab 1 Pre-Lab Exercise:
PLEASE WATCH THIS INTRODUCTORY VIDEO PRIOR TO CLASS
The process of identifying structures before going to lab is also critical to your success in lab.
1. Review the basic structure of the skin [Histology site]. Return to Dr. Cabrey’s lecture and your histology textbook for a review.
The epidermis is composed of a stratified, keratinized epithelium; underneath is the dense, irregular connective tissue of the dermis. Beneath the dermis is a loose connective tissue, containing varying numbers of fat cells, called the hypodermis -- or in gross anatomical terms, the superficial fascia. You will be able to distinguish somewhat dermis and epidermis in lab and to a greater degree the former two from hypodermis.
- Observe how the skin on the back of your own hand moves freely over the underlying structures.
- Compare the mobility of the skin on the back of your hand with that on your palm.
Consider what you have learned about thick and thin skin in microanatomy. The superficial fascia allows for mobility, and also functions in fat storage. Where the skin is mobile, it can be separated easily from underlying muscle along the plane of the loose connective tissue of the superficial fascia. Always strive to locate this plane when skinning.
The deep fascia is more immobile; it encloses and binds together the underlying muscle tissue. Deep fascia is inelastic, and like tendons (muscle-to-bone), ligaments (bone-to-bone), and aponeuroses (broad tendons) is composed largely of collagen fibers. Its inelasticity explains why it is poorly developed over much of the thorax and abdomen, which must expand and contract in breathing. Deep fascia defines one muscle from another, passing between adjoining muscles to form intermuscular septa attached to the underlying bones. On the palms and soles, superficial fascia becomes dense and tightly bound to the deep fascia.
Atlas images related to histology of the skin:
2. Review the bony anatomy. In general, it is always best to review bone anatomy using both an anatomy atlas AND a physical specimen or model. There is a model room, and there are articulated skeletons in the anatomy lab, both of of which you will be told about during the introductory gross anatomy lecture. In addition, you will also be issued a disarticulated skeleton, which you can use to study on your own. As we are at the very beginning of the course, these resources are not yet available to you, but, for now, your atlas will be sufficient.
Using atlas diagrams:
You will use all these landmarks to identify surface anatomical locations on the on the cadaver and guide your dissection.
- Examine the articulations of the base of the skull, the atlas (C.1 vertebra), and the axis (C.2 vertebra).
Specializations of the first two vertebrae facilitate rotation of the head on the vertebral column. The dens of C.2 is the detached vertebral body of C.1.
- Relate the actions of the suboccipital muscles to their attachments by studying one of the articulated skeletons in the lab.