BI 121 LAB. WEEK 2: Tissues (continued); Integumentary System

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1 BI 121 LAB 2-1 WEEK 2: Tissues (continued); Integumentary System This week you will 1) Review the four major tissue types 2) Review the characteristics of epithelial tissues. 3) Learn the major characteristics of each of the other three major tissue types. 4) Learn the basic characteristics of the integumentary system. TISSUES: CLASSIFICATION AND STRUCTURAL CHARACTERISTICS Obj 1 Review the four major tissue types of the body. [M:p114, Fig 4.1; Tissues Supplement] epithelial, connective, muscle, nervous Obj 2 Review the epithelial tissues you studied last week. Obj 3 Describe the structural characteristics of connective tissues, Connective Tissues (CT) General structural features: 1. cells scattered, not touching or in a regular arrangement such as layers 2. usually abundant matrix 3. matrix contains chemical fibers and blood vessels (some subtypes are avascular) [M:p , Fig4.7, Table 4.1] Obj 4 Identify connective tissues and the sub-types of connective tissues listed below. Describe the differences between the subtypes of connective tissues. subtypes: There are loose and dense connective tissues, cartilage, plus specialized types (bone and blood)you will study in more detail with particular organ systems.

2 2-2 Refer to the Summary of Tissues at the end of this lab for an overview of tissue types. You will also want to take this Summary of Tissues with you to lecture. You will be held responsible in lab for only those listed below. Draw a small, representative portion of each slide, emphasizing the characteristics of each subtype. 1. loose CT, areolar: S-matrix has relatively few fibers embedded in an abundant gel-like material slide:areolar tissue, spread [M:Fig4.8a] 2. loose CT, adipose: S-cells pushed tightly together by accumulated stored lipid; nucleus flattened and peripheral slide:adipose tissue [M:Fig4.8b] Dense CT: S-matrix has abundant, tightly packed fibers and little other material 3. dense regular CT: S-fibers mostly parallel slide: yellow elastic tissue [M:Fig 4.8d] 4. dense irregular CT: S-fibers in non-parallel 'bunches' slide:skin corpuscle, human [M:Fig 4.8e] 5. cartilage qualities intermediate between dense CT & bone slide: trachea

3 [M:Fig 4.8g;] bone slide: ground bone [M:4.9j] 7. blood liquid matrix (plasma)+ blood cells; circulates slide: human blood, Wright stain [M:Fig4.9k] TO QUIZ: Set up slides(label covered) for a lab partner and ask her/him to identify the type and subtype of tissue. Also have her/him put the pointer on structural features visible on the slide. Obj 5 Describe the structural characteristics of nervous tissue. Identify nervous tissue. Nervous Tissue General structural features: 1. tightly packed cells 2. little matrix 3. elongated cytoplasmic extensions which connect to other cells slide: neuron, ox [M: p , Fig 4.9] Obj 6 Describe the structural characteristics of muscle tissue. Identify muscle tissue. Muscle Tissue General structural features: 1. cells tightly packed 2. small amount of matrix 3. elongate cells There are 3 types of muscle tissue (skeletal, smooth, & cardiac). At this time we will only look at skeletal muscle. We will look at all 3 types of muscle tissue when we study muscles in Week 5. slide: skeletal muscle, human [M:p , Fig 4.10a]

4 2-4 Now that you have looked at these slides, examine a chicken drumstick and identify the adipose tissue, loose connective tissue, cartilage, and dense regular connective tissue. Compare their macroscopic appearance with their microscopic appearance. THE INTEGUMENTARY SYSTEM The skin consists of two distinct layers, the epidermis and the dermis, plus structures embedded in them (hairs, nails, sweat glands and sebaceous glands). Below the skin are two associated layers, the subcutaneous layer and the deep fascia, which will also be studied this week. THE SKIN Obj 1 Name the tissue type and subtype composing the epidermis and the dermis and recognize the structural features of these tissues on the slides referred to below. [M: p ,Fig 5.1-3] epidermis: stratified squamous epithelium dermis: dense irregular connective tissue (primarily) Obj 2 Identify the following structures of the skin's layers and the layers beneath it. Please note that not all layers or structures will be visible on all slides or models. models: skin, composite ( skin large, skin small, skin with hair and nail ) slide: skin, corpuscle (* = you will not need to find these structures on the slide) slide: skin, pigmented(=thin Negroid skin) [M: ,Fig 5.1-4] Make drawings of these two slides, labeling the structures you are to identify. Epidermis stratum corneum, {s. lucidum, s. granulosum, s.spinosum}, s. basale; melanin layer,{melanocytes}; {epidermal ridges and sweat gland openings} Dermis dermal papilla, papillary layer, reticular layer, blood vessels*, sensory receptors*, nerves*, sweat glands

5 2-5 Subcutaneous layer adipose tissue {Deep Fascia} {dense irregular connective tissue} Obj 3 Identify the indicated structures embedded in the layers of the skin and in its underlying subcutaneous layer. model: skin, composite slides: scalp,l.s.; skin, corpuscle yourself: hairs and nails [M:p , Fig ] Make drawings of these two slides, labeling the structures you are to identify. Glands (Fig 5.5) sweat glands(secretory portion, excretory duct), sebaceous glands Hairs (Fig 5.6) hair(shaft, root), follicle(bulb, hair papilla), arrector pili muscle Nails (Fig 5.7) nail bed, lunula Obj 4 Name the two parts of the body with 'thick' skin. [M:p150] The differentiation between thick skin and thin skin is based on the thickness of the epidermis, not on the thickness of the entire skin. The palms and soles have the thickest epidermis. The total thickness of the skin is greater on the back, however, because the dermis accounts for most of the skin's thickness. Microscopically thick skin can be distinguished by its stratum lucidum. Obj 5 Locate places on your body where the skin is bound firmly down to the underlying dense fibrous connective tissue. yourself

6 2-6 The skin is bound tightly where it needs to not 'slide', as for gripping by the palms and soles. Obj 6 Locate places on your body where skeletal muscle inserts directly into the skin and pulls on it. yourself Muscles which insert into the skin, if used frequently, pull the skin into 'stress lines'. These are more obvious with age, as the dermis elasticity decreases, e.g., lines of facial expression.