integumentary system lab

Tools for Studying Histology

  • Utilization of microscopes and slide boxes at the Learning Center to study histological tissues.

  • Availability of microscope slides for independent study outside of class hours.

  • Importance of using diverse study methods, such as visual aids, descriptions, and practical examination of slides.

Testing Focus

  • Exam questions will require you to identify tissue types based on appearance rather than definitions.

  • Understanding that lab exams consist mainly of identification questions, focusing on memorization.

  • Recognizing specific structures, like lacunae in cartilage and bone, is essential for identification.

Cartilage Types

Overview of Cartilage

  • Cartilage is characterized by a dense, supportive matrix.

  • Structural examples include cartilage in the nose and ear which provides flexibility yet maintains shape.

  • Living cells within cartilage (chondrocytes) exist in cavities called lacunae, providing necessary space for growth.

Hyaline Cartilage

  • Described as having a glassy, smooth matrix, usually pink/lavender in stained sections.

  • Essential characteristics include the presence of lacunae with chondrocytes.

  • Identification technique: Look for texture and compare against other tissues.

Elastic Cartilage

  • Identified by the presence of elastic fibers in the matrix; appears fibrous or textured in nature.

  • Lacunae associated with chondrocytes are visible.

  • Understanding the structural differences between hyaline and elastic cartilage is crucial for identification.

Connective Tissue Types

Dense Regular Connective Tissue

  • Features parallel collagen bundles providing strength and structural integrity, seen in tendons and ligaments.

  • Fibroblasts are the predominant cell type, responsible for producing collagen.

  • Important for identifying tissue based on the alignment of fibers and nuclei.

Dense Irregular Connective Tissue

  • Characterized by collagen fibers arranged in multiple directions, giving a marbled appearance (like marbled steak).

  • Found primarily in the dermis of the skin, providing resistance against multidirectional forces.

  • Scattered fibroblasts are present within this tissue.

Muscle Tissue

Skeletal Muscle

  • Defined by its large, striated fibers with multiple nuclei (formed during embryonic development).

  • Unique striations visible under high magnification due to the arrangement of proteins within muscle cells.

  • Recognition is based on the visual presence of these striations and the fiber's size.

Nervous Tissue

Neurons

  • Neurons display a unique structure with a prominent nucleus and multiple extensions (dendrites and axons).

  • Identification involves recognizing multipolar neurons typically found in the brain or spinal cord.

  • Focus on low magnification to locate neurons before examining finer details.

Integumentary System

Layers of Thick Skin

  • The epidermis consists of five layers (strata):

  1. Stratum corneum

  2. Stratum lucidum

  3. Stratum granulosum

  4. Stratum spinosum

  5. Stratum germinativum

  • Each layer has distinct functions, biochemical processes, and appearances important for identification.

  • Mnemonic for remembering order: "Cory Lucille Granny Speaks German" (Cory = Corneum, Lucille = Lucidum, Granny = Granulosum, Speaks = Spinosum, German = Germinativum).

Observing Layers

  • Use high magnification to distinguish between layers, especially noting cell appearance as they move from alive, mitotically active cells to dead cells in layers near the surface.

  • Importance of the basement membrane in delineating the transition from epithelial to connective tissue (dermis).

Structures Associated with Hair Follicles in the Scalp

  • Erector Pili Muscle: Smooth muscle attached to hair follicles, contracts to create goosebumps.

  • Sebaceous Glands: Produce oil to keep hair moist. Appearance resembles frothy structures on the slide.

  • Sweat Glands: Coiled structures, deeper than sebaceous glands, lined with simple cuboidal epithelium.

Techniques for Identifying Tissue Types

  • Important to scan slides for key characteristics and seek assistance when uncertain.

  • Review the orientation of tissues, utilizing colors, textures, and cellular arrangements as guides.

  • Engage with practical examinations by looking at various slides to develop a comprehensive understanding of each tissue type.