Lab 7: Integumentary System Hamilton ANSWERS TO PRE- LAB ASSIGNMENTS Pre-Lab Activity 1: 1. a. epidermis b. dermis c. hypodermis d. adipose tissue e. hair f. sebaceous gland g. sweat gland 2. a Pre-Lab Activity 2: 1. a 2. a. E b. D c. D d. E e. D f. D g. D 3. b Pre-Lab Activity 3: 1. b 2. b ANSWERS TO ACTIVITY QUESTIONS Activity 1 1. keratinized stratified squamous epithelium 2. Stratum basale single layer of cells; keratinocytes, melanocytes, Merkel cells Stratum spinosum 8 10 layers; keratinocytes, dendritic cells Stratum granulosum 3 5 layers; keratinocytes Stratum lucidum 2 4 layers; keratinocytes Stratum corneum 20 30 layers of cells; keratinocytes 3. papillary layer areolar connective tissue\ reticular layer dense irregular connective tissue
4. Answers will vary. Possible answers: a. Sebaceous gland produces sebum, associated with a hair follicle, exocrine gland b. Eccrine sweat gland produces sweat, regulates body temperature, exocrine gland c. Apocrine sweat gland produces sweat, associated with a hair follicle; activated at puberty d. Arrector pili muscle smooth muscle, causes hair to stand on end (goose bumps), attached to hair follicle e. Dermal papillae fingerlike projections, contain capillary loops or tactile corpuscles, areolar connective tissue f. Hair follicle hair papilla, epidermal root sheath, dermal root sheath g. Tactile (Meissner s) corpuscle dermal papilla, responds to light touch, encapsulated structure h. Lamellated (Pacinian) corpuscle reticular layer, responds to deep pressure, multilayered capsule i. Sensory receptor some free nerve endings; some connected to base of hair follicle, respond to light touch Activity 2 1. stratum lucidum, matrix of hair bulb 2. papillae, stratum lucidum 3. melanocytes, stratum basale 4. answers vary; eccrine sweat glands are small structures with a central opening (lumen) whereas sebaceous glands are larger structures composed of larger whitish cells 5. dermis; a suntan occurs in the epidermal cells which eventually slough off whereas a tattoo effects the dermis which does not slough off Activity 3 1. student prediction 2. c. student data 3. student data 4. student data
ANSWERS TO POST- LAB ASSIGNMENTS PART I. Check Your Understanding Activity 1: Identifying and Describing Skin Structures 1. Identify the components of skin in the accompanying diagram: a. hair b. sebaceous gland c. duct of sweat gland d. eccrine sweat gland e. hypodermis f. sensory receptor g. adipose h. arrector pili muscle i. epidermis j. dermis 2. Which of the following structures is found in the epidermis? a. tactile corpuscle b. arrector pili muscle c. lamellated corpuscle d. eccrine sweat gland e. None of these structures are found in the epidermis.
3. The papillary layer of the dermis is composed primarily of which type of tissue? a. stratified squamous epithelial tissue b. dense irregular connective tissue c. simple cuboidal epithelial tissue d. loose connective tissue 4. For each of the following characteristics, indicate whether it describes apocrine (A) or eccrine (E) sweat glands: A a. Are found primarily in the groin and axillae E b. Function primarily in temperature regulation A c. Are located deep in the dermis A d. Have ducts that empty into hair follicles E e. Open onto the skin surface E f. Are located across most of the body surface Activity 2: Examining the Histology of the Skin 1. The narrow epidermal layer that appears clear is the: a. stratum granulosum. b. stratum corneum. c. stratum basale. d. stratum spinosum. e. stratum lucidum. 2. Which epidermal stratum is missing in thin skin? a. stratum corneum b. stratum basale c. stratum lucidum d. stratum spinosum e. stratum granulosum 3. True or false?: Unlike a suntan, which is lost because of constant renewal of keratinocytes, a tattoo is usually permanent because the pigments are in the dermis, which does not have significant cell turnover. Activity 3: Determining Sweat Gland Distribution 1. True or false?: Eccrine sweat glands are located in the skin of the palm and forehead, but not in the forearm.
PART II. Putting It All Together A. Review Questions Answer the following questions using your lecture notes, your textbook, and your lab notes: 1. For each skin structure, write one of its functions and the skin layer in which it is found. a. hair matrix mitotically active part of hair; dermis b. dendritic cell functions in phagocytosis; epidermis c. keratinocyte produces keratia; epidermis d. collagen fibers gives dermis strength; dermis e. dermal papillae contains capillary loops; papillary layer-dermis f. stratum basale actively mitotic cells; epidermis 2. If you cut the palm of your hand, but do not bleed: a. the cut has penetrated through the epidermis into the dermis. b. it is because blood vessels are located in the hypodermis only. c. you have injured the epidermis but not the dermis. d. it is because blood in the epidermal blood vessels clots very quickly. 3. Which of the following statements about melanocytes and keratinocytes is true? a. Melanocytes are in the dermis and keratinocytes are in the epidermis. b. Melanocytes produce pigment but keratinocytes do not. c. Both cell types produce waterproofing material. d. Both cell types divide and die as they move away from their blood supply. 4. True or false?: Lamellated corpuscles detect pressure, whereas tactile corpuscles detect light touch.