BIO 251 SKIN STRUCTURE CHAMBERLAIN UNIVERSITY FINAL SET EXAM 3 2025

BIO 251 SKIN STRUCTURE CHAMBERLAIN UNIVERSITY FINAL SET EXAM 3 2025 Structure of skin Epidermis, dermis, hypodermis What are the functions of the skin? Protection, vitamin d synthesis, sensation, thermoregulation, nonverbal communication Accessory structures of the skin Hair, skin, sweat glands, and nails Main fibers found in dermis Collagen, elastic, and reticular fibers What does the collagen fiber provide for the dermis? Strength What does the elastic fiber provide for the dermis? Stretch recoil Arrector pili muscle Causes hair to stand on end and goose bumps to appear Sebaceous glands Secrete sebum, lubricates skin and hair, controls bacteria Sudariferous glands Sweat glands Medulla Inner most layer of hair Cortex The middle layer of the hair provides strength, color, and texture Cuticle (hair) Tough, clear outside covering of the hair shaft Dermal papilla Groves that form finger prints Papillary layer of dermis Upper layer of dermis, made of areolar tissue, supplies nutrients to epidermis, helps regulate temperature Reticular layer of dermis Deeper, thicker layer of dermis, made of dense irregular ct, full of fibers for strength, elasticity Subcutaneous layer (hypodermis) BIO 251 BIO 251 The lowest layer of skin, consists of loose connective tissue (adipose, areolar) Thick skin Covers the palms of the hands and soles of the feet has 5 layers of keratinocytes Thin skin Covers most of the body has 4 layers of keratinocytes Eccerine sweat glands All over, abundant in palms, soles, forehead, cool body Appocrine glands Thicker milky sweat, respondes to stress and sexual stimulation, found in groin and armpits Anagen phase Growth phase 6-8 years Catagen phase Mitosis stop, transition stage, 2-3 weeks Telogen phase of hair growth Resting phase, 1-3 months Basal cell carcinoma Most common type of skin cancer, appears as shiny small bump Squamous cell carcinoma Can lead to metastasis, tumor of the squamous epithelium, red, scaly appearance Melanoma Aggressive and can quickly metastasize, often brown or black in color, uses abcd rule The four types of cells in bone tissue include: 1. Osteoprogenitor cells 2. Osteoblasts 3. Osteocytes 4. Osteoclasts Six major functions of the skeletal system Blood formation support protection movement storage and release of minerals store triglycerides Osteoprogenitor cells Stem cells that divide to produce osteoblasts Osteoblasts Bone building cells, secrete matrix Osteocytes Mature bone cells, maintain bone matrix, lay in the lacunae Osteoclasts function BIO 251 BIO 251 Resorption, breakdown of bone matrix, causes bone to release calcium Compact bone Provides protection and support, is dense, composed of osteons Spongy bone Lightweight, provides tissue support, osteocystes are found in the trabecular, filled with red bone marrow. Tendons Connect muscle to bone Ligaments Connect bone to bone Ossification (osteogenesis) Process of bone formation Intramembranous ossification Bone develops from ct fibrous membrane, produces flat bones of skull and clavicle Endochondral ossification Transforming cartilage into bone in fetuses. Origin is hyaline cartilage Endochondral ossification also occurs in? The epiphysial plates of long bones as they grow in length Appositional growth Happening throughout our life, occurs at bone surface Main minerals for healthy bone growth Calcium and phosphorus as well as trace minerals magnesium, fluoride, and manganese. Long bone Longer than they are wide Flat bones Wider than it is long Short bones Just as long as it is wide Irregular bones No two bones being the exact same Sesamoid bone Patella (knee cap) Periosteum A dense fibrous membrane covering the surface of bones Endostium Thin layer of connective tissue lining the medullary cavity. Metaphysis Where diaphysis and epiphysis meet, contains growth plate The red bone marrow inside the medullary cavity is replaced by what in adulthood? BIO 251 BIO 251 Yellow bone marrow The inner layer of the periosteum is lined with what that allows bone remodeling? Osteogenic layer lined with osteoblasts and allows for bone remodeling and growth Growth: epiphyseal plate Growth happens at the growth plates of long bones and resembles endochondral bone growth. Consists of hyaline cartilage, found in metaphysis of bone Remodeling Process of appositional growth, occurs when bone is stressed. Steps of bone repair Hematoma forms, fibrocartilaginous callus forms, bony callus forms, bone remodeling occurs. Phases of bone repair in order: 1. Reactive phase: inflammatory 2. Repair phase: soft & hard callus forms 3. Remodeling: hard callus removed, bone remodels Vitamin a Osteoblast activity Vitamin c Collagen synthesis Vitamin k and b12 in bone growth Bone protein Vitamin d Helps with absorption of calcium from small instestines into the blood stream How much calcium is found in the skeletal system? 99% Parathyroid hormone (pth) Secretes parathyroid hormone when calcium gets too low. Increases osteoclast activity that secretes the calcium into the blood Calcitriol (vitamin d) Kidneys release calcitriol which targets the small intestine to absorb nutrient into the blood stream Calcitonin Lowers blood calcium levels How many bones does the axial skeleton have ? 80 How many bones does the appendicular skeleton have? 126, total bones are 206 BIO 251 BIO 251 Two major surface markings on bone Depression/openings, processes What are the 3 auditory ossicles of the middle ear? Mallus, incus, stapies Depressions and openings Fissure, foramen, fossa, sulcus, meatus Processes Condyle, facet, head, femur, crest, trochanter, spinous process Trochanter Large projection only found in the femur The functions of the paranasal sin