BMS 250 Unit Two: Vocabulary

Ligament

Dense regular connective tissue that connects bone to bone

Tendon

Dense regular connective tissue that connects bone to muscle

Dermal Papillae

Interlock with epidermal ridges to increase area of contact between layers

Integument

Skin (cutaneous membrane) Barrier to the outside world Visual indicator of our physiology and health

Anemia

A condition characterized by reduced erythrocytes

Diaphysis

A region of long bone Elongated, usually cylindrical shaft Provides leverage and weight support Composed of compact bone with thin spicules of spongy bone extending inward

Medullary Cavity

A region of long bone Hollow, cylindrical space within the diaphysis Contains red bone marrow in children Contains yellow bone marrow in adults

Metaphysis

A region of long bone Region where bone widens and transfers weight between the diaphysis and epiphysis Contains the epiphyseal plate/line

Epiphysis

A region of long bone The knobby region at the end of each long bone (has diverse appearances) Each bone has a proximal and distal one Contains articular cartilage Composed of an outer thin layer of compact bone and an inner region of spongy bone

Nutrient Foramen

A small opening or hole in bone Arteries enter and veins exit here

Irregular Bone

A type of bone that can have elaborate, sometimes complex shapes

Flat Bone

A type of bone that is flat, thin, and may be slightly curved

Long Bone

A type of bone that is greater in length than in width

Short Bone

A type of bone that is nearly equal in length to width

Fibrocartilage

A type of cartilage Weight-bearing cartilage that withstands compression (shock absorption) Functions as intervertebral discs, pubic symphysis, and menisci of knees

Simple Fracture

A type of fracture Broken bone not penetrating skin

Pathologic Fracture

A type of fracture Occurs in bone weakened by disease

Compound Fracture

A type of fracture One or both ends of the bone pierce the overlying skin

Stress Fracture

A type of fracture Thin break caused by increased physical activity

Anagen Phase

Active phase of hair growth

Calcitonin

Aids in regulating blood calcium levels Less significant role than PTH or calcitriol Released from the thyroid gland in response to high blood calcium levels Also secreted in response to exercise Inhibits osteoclast activity Stimulates kidneys to increase loss of calcium in the urine Greatest effect during greatest bone turnover (ex: growing children)

Osteon (Haversian System)

Basic functional and structural unit of mature compact bone Oriented parallel to bone diaphysis Looks like a bull's eye target

Endochondral Ossification

Begins with a hyaline cartilage model Produces most bones of skeleton (upper and lower limbs, pelvis, vertebrae, ends of clavicle) Ex: long bone development

Hypodermis (Subcutaneous Layer)

Beneath the dermis Not part of the integumentary system --> acts as a border Composed of alveolar tissue, connective tissue, and adipose tissue

Intramembranous Ossification (Dermal Ossification)

Bone growth within a membrane Produces flat bones of skull, some facial bones, mandible, central part of the clavicle

Dermis

Bottom layer of the integument Composed of dense irregular connective tissue and areolar connective tissue

Fracture

Break in a bone

Catagen Phase

Brief regression period where cell division stops Hair remains in the follicle

Spongy Bone

Cancellous or trabecular bone Located internal to compact bone Appears porous 20% of bone mass

Acne

Caused by plugged sebaceous ducts Typically begins during puberty Increased activity in gland secretions may block pores May lead to scarring if not treated

Chondrocyte

Chondroblast encased within the matrix Occupies small space called lacunae Maintains the cartilage matrix

Terminal Hair

Coarser, pigmented, longer hair On scalp, eyebrows, eyelashes, men's beards During puberty, replaces vellus hair in axillary and pubic regions

Apocrine Sweat Gland

Coiled, tubular gland Discharges secretions into hair follicles located in the axillary regions, around the nipples, in the pubic region, and in the anal region Produces secretion by exocytosis Produces viscous, cloudy secretions (less water-based) Starts producing these secretions during puberty

Perforating Fibers

Collagen fibers that secure periosteum to underlying bone

Hair Papillae

Composed of connective tissue Vessels, nerves

Albinism

Condition in which melanocytes are unable to produce melanin, causing all parts of the integumentary system to lack pigment

Nail Plate

Consists of the free edge, nail body, and nail root

Bone Remodeling

Continues throughout childhood Occurs at periosteal and endosteal surfaces of a bone Occurs at different rates 20% of skeleton replaced yearly Dependent upon the coordinated activities of osteoblasts, osteocytes, and osteoclasts Influenced by hormones and mechanical stress

Endosteum

Covers all internal surfaces of bone within the medullary cavity A thin layer of connective tissue containing osteoprogenitor cells, osteoblasts, and osteoclasts

Thin Skin

Covers most of the body Lacks a stratum lucidum (has 4/5 layers) Contains sweat glands, hair follicles, and sebaceous glands

Integumentary System

Covers the body and consists of skin and accessary tissues (nails, hair, sweat glands, sebaceous glands)

Reticular Layer

Deeper, major portion of the dermis Composed of dense irregular connective tissue

Stratum Basale

Deepest epidermal layer single layer of cuboidal to low columnar cells Contains keratinocytes. melanocytes, and tactile cells

Perichondrium

Dense irregular connective tissue Covers cartilage and helps maintain its shape

Compact Bone

Dense or cortical bone 80% of bone mass

Free Edge of Nail

Distal end of the nail Whitish Contains no underlying capillaries

Sex Hormones

Estrogen and testosterone Secreted in large amounts at puberty (dramatically accelerate bone growth) Increase rate of cartilage growth and bone formation in epiphyseal plate Bone formation rate greater than cartilage growth (eventually cartilage is replaced with bone, stopping growth)

Zone of Ossification

Fifth zone of the epiphyseal plate Walls break down between lacunae columns Spaces are invaded by capillaries and osteoprogenitor cells New bone matrix is deposited on the calcified cartilage matrix

Vellus

Fine hair Primary human hair Found on upper and lower limbs

Lanugo

Fine, unpigmented, downy hair Appears in the last trimester of pregnancy and is on newborns

Zone of Resting Cartilage

First zone of the epiphyseal plate Zone nearest to the epiphysis Small chondrocytes distributed throughout the matrix Resembles mature hyaline cartilage Secures epiphysis to epiphyseal plate

Cortex

Flattened cells closer to the outer hair surface Relatively hard

Ossification (Osteogenesis)

Formation and development of bone connective tissue Begins in the embryo, continues through childhood and adolescence Skeleton begins forming by week 8-12 of embryonic development Occurs by intramembranous ossification or endochondral ossification

Osteoblast

Forms from osteoprogenitor stem cell Synthesizes and secretes osteoid Becomes entrapped within its matrix (now in lacuna) Differentiates into an osteocyte

Keratinicoyte

Found in all layers of the epidermis Synthesize keratin

Zone of Calcified Cartilage

Fourth zone of the epiphyseal plate Composed of 2-3 layers of chondrocytes Minerals are deposited between columns of lacunae Destroys chondroctes

Sweat Gland

Gland that secretes water-based secretions

Glucocorticoids

Group of steroid hormones Released from adrenal cortex Regulate blood glucose level High amounts increase bone loss (impairs growth at epiphyseal plate in children)

Interstitial Growth

Growth in length

Appositional Growth

Growth in width

Red Bone Marrow (Myeloid Tissue)

Hematopoietic (forms blood cells) Contains reticular connective tissue, developing blood cells, and adipocytes

Sebaceous Gland

Holocrine gland Produces an oily secretion called sebum Secretion is stimulated by hormones (especially male sex hormones) Activated during puberty

Thyroid Hormone

Hormone that is secreted by the thyroid gland Influences basal metabolic rate of bone cells Regulates normal activity at epiphyseal plates

Osteoid

Initial semisolid organic form of bone matrix Later calcifies, becoming bone

Epithelial Tissue Root Sheath (of Hair Follicle)

Inner layer of hair follicle Originates in epidermis

Osteopenia

Insufficient ossification Occurs slightly in all people with age Begins age 35-40 Osteoblast activity declines, osteoclast activity is at previous levels Vertebrae, jaw, bones, epiphysis lose large amount of mass Women lose more of their skeletal mass every decade than men

Hair

Keratinized cells that form a slender filament Grows from follicles Found almost everywhere on the body

Keratinization

Keratinocytes fill with keratin, beginning the cellular death process Nucleus and organelles disintegrate

Friction Ridges

Large folds and valleys of dermis and epidermis Create fingerprints

Osteocyte

Mature bone cell derived from osteoblast Detects stress on bone, triggering new bone formation Mature bone cell Found in small spaces between concentric lamellae (lacunae) Maintain bone matrix

Osteoclast

Large, multinuclear, phagocytic cell Derived from fused bone marrow cell Ruffled border increases surface area exposed to bone Located within/adjacent to a depression/pit on bone surface (resorption lacuna) Involved in bone resorption (breakdown of bone)

Dermis

Layer of the integument deep to the epidermis Composed of connective tissue proper (dense irregular connective tissue) Contains blood vessels, sweat glands, sebaceous glands, hair follicles, nail roots, sensory nerve endings, arrector pili, motile dendritic cells Composed of the papillary layer and reticular layer

First-Degree Burn

Least severe burn type Involves only the epidermis Causes slight redness and pain Burned area should be immersed in cool water

Nevus (Mole)

Localized overgrowth of melanocytes Should be monitored for changes that suggest malignancy

Thick Skin

Located on the palms of the hands and the soles of the feet Contains all five layers of epidermal strata Contains sweat glands but no hair follicles or sebaceous glands

Epiphyseal Plate

Located within the metaphysis "Growth plate" Thin layer of hyaline cartilage Provides for lengthwise bone growth

Epidermal Dendritic Cell

Migratory cells that initiate immune response to foreign materials Found in stratum spinosum and stratum granulosum

Ceruminous Gland

Modified apocrine sweat gland Located only in external ear canal Secretes waterproof earwax (cerumen)

Mammary Gland

Modified apocrine sweat gland of breast Only functions in pregnant and lactating females Produces breast milk

Merocrine (Eccrine) Sweat Gland

Most numerous and widely-distributed type of sweat gland Simple, coiled tubular gland Discharges secretions onto the skin surface Produces secretion by exocytosis Secretes sweat Has a major role in thermoregulation

Third-Degree Burn

Most severe burn type Involves the epidermis, dermis, and subcutaneous layer Requires hospitalization Requires treatment for dehydration and infection Requires additional caloric intake Causes severe scarring May require debridement and skin graft

Stratum Corneum

Most superficial layer of the epidermis Composed of 20-30 layers of dead, interlocking, anucleate, keratinized cell Dry, thickened surface is protective against abrasion and infection

Serotonin

Neurotransmitter and hormone Most bones have receptors for this hormone Has a role in rate an regulation of normal bone remodeling If levels are too high: osteoprogenitor cells won't differentiate into osteoblasts; linked ot low bone density disorders

Hair Follicle

Oblique tube surrounding hair root Extends into dermis and sometimes the subcutaneous layer Outer connective tissue root sheath originates in dermis Inner epithelial tissue root sheath originates in the epidermis

Mechanical Stress

Occurs in weigh-bearing movement and exercise Required for normal bone remodeling Detected by osteocytes and communicated to osteoblasts (increases synthesis of osteoid) Increased bone mass (from weight-bearing activities) Decreased bone mass (from removal of mechanical stress)

Sebum

Oily secretion produced by sebaceous glands Lubricant for skin and hair Bactericidal Discharges into a hair follicle

Connective Tissue Root Sheath (of Hair Follicle)

Outer layer of hair follicle Originates in dermis

Hemoglobin

Oxygen-binding protein in red blood cells Bright red color upon bonding to oxygen

Nail Root

Part of the nail that is embedded in the skin

Melanosome

Pigment granules that shield nuclear DNA from UV radiation

Melanin

Pigment that gives skin its color

Nail Body

Pinkish part of the nail Contains underlying cavities

Shaft

Portion of hair beyond the skin surface

Woven Bone

Primary bone Immature, poorly organized bone

Bone Connective Tissue (Osseous Connective Tissue)

Primary component of bone Bone is composed of cells and extracellular matrix

Bone

Primary organ of the skeletal system The rigid framework of the body Has many functions

Melanocyte

Produces and stores pigment in response to UV light Transfers pigment granules into keratinocytes

Chondroblast

Produces cartilage matrix

Yellow Bone Marrow

Product of red bone marrow degeneration as children mature Fatty substance May convert back to red bone marrow during severe anemia in adulthood Facilitates production of additional erythrocytes

Hematopoesis

Production of blood cells Occurs in red bone marrow connective tissue

Keratin

Protein that strengthens the epidermis

Osteoporosis

Reduced bone mass sufficient enough to compromise normal function Occurs in a significant percentage of older individuals

Medulla

Remnant of matrix Flexible, soft keratin Thin hair lacks this

Telagen Phase

Resting phase in which the hair is usually shed from the follicle

Nail

Scalelike modification of stratum corneum Covers the dorsal edge of fingers and toes Protects the distal tips of digits Assists in grasping objects

Stratum Spinosum

Second deepest layer of the epidermis Several layers of polygonal keratinocytes New cells from the stratum basale are pushed into this layer Contains epidermal dendritic cells

Stratum Lucidum

Second deepest layer of the epidermis Translucent layer that is 2-3 cell layers thick Found only on the thick skin of palms and soles

Second-Degree Burn

Second most severe burn type Involves the epidermis and part of the dermis Causes painful skin blisters Causes slight scarring

Zone of Proliferating Cartilage

Second zone of the epiphyseal plate Chondrocytes undergo rapid mitotic division Align into longitudinal columns of flattened lacunae Columns parallel ot diaphysis

Parathyroid Hormone

Secreted and released by parathyroid glands in response to reduced blood calcium levels Accelerates conversion to calcitriol by kidneys

Sweat

Secretion composed of 99% water and 1% other chemicals including electrolytes, metabolites, and waste products

Cartilage

Semirigid connective tissue that is more flexible than bone Two types: hyaline and fibro

Tactile Cell (Merkel Cell)

Sensitive to touch When compressed, it releases chemicals to stimulate sensory nerve endings

Cuticle

Single cell layer around the hair cortex

Bone Marrow

Soft connective tissue within the medullary cavity of bones

Insulin-Like Growth Factor

Somatomedin Hormone that directly stimulates growth of cartilage in epiphyseal plate

Growth Hormone

Somatotropin Hormone produced by anterior pituitary gland Stimulates the liver to produce insulin-like growth factor Directly stimulates growth of cartilage in epiphyseal plate

Osteoprogenitor Cell

Stem cell derived from mesenchyme Cellular division yields another stem cell and a "committed cell" Matures to become an osteoblast Located in periosteum and endosteum

Striae

Stretch marks Occur when skin of the dermis is stretched beyond its capabilities

Interstitial Lamellae

Structure of long bone Components of compact bone between osteons or partially resorbed osteons

Circumferential Lamellae

Structure of long bone Contains both external and internal Both run the entire circumference of the bone

Perforating Canal (Volkmann Canal)

Structure of long bone Perpendicular to central canals Connects central canals within different osteons

External Circumferential Lamellae

Structure of long bone Rings of bone that run immediately internal to the periosteum

Internal Circumferential Lamellae

Structure of long boneRings of bone that run internal to the endosteum

Central Canal (Haversian Canal)

Structure of osteon Cylindrical channel at the center of an osteon and parallel to it Blood vessels and nerves extend through the channel

Concentric Lamellae

Structure of osteon Rings of bone connective tissue Surrounds central canal Contains collagen fibers

Canaliculi

Structure of osteon Tiny, interconnecting channels within bone connective tissue Extend from each lacuna, travel through lamellae and connect to lacunae and central canal House of osteocyte projections that allow intercellular contact Allow exchange of nutrients, minerals, gases, and wastes between blood vessels and osteocytes

Parallel Lamellae

Structure of spongy bone Bone matrix Osteocytes between lamellae Canaliculi radiate from lacunae

Trabeculae

Structure of spongy bone Open lattice of narrow rods and plates of bones Bone marrow fills spaces Meshwork of crisscrossing bars Resistant to stresses

Dermatology

Study of the skin

Subcutaneous Layer (Hypodermis)

Superficial fascia beneath the dermis Not part of the integument Functions: protection, energy storage, insulation Common drug injection site Thickness/distribution is influenced by sex hormones

Papillary Layer

Superficial region of the dermis Composed of areolar connective tissue Named for the projections of the dermis (dermal papillae)

Nail Matrix

The actively growing part of the nail at the proximal end of the nail body

Calcification (Mineralization)

The deposition of hydroxyapatite crystals into osteoid

Proximal Epiphysis

The end of a long bone closest to the trunk of the body

Distal Epiphysis

The end of a long bone farthest from the trunk of the body

Nail Fold

The fold of skin overlapping the nail on the medial and lateral sides

Eponychium (Cuticle)

The narrow band of epidermis from the margin of the nail wall onto the nail body

Bone Resorption

The process in which bone matrix is destroyed by substances released from osteoclasts Occurs when blood calcium levels are low

Epiphyseal Line

The remnant of the epiphyseal plate in adults once bone growth has finished

Hair Bulb

The selling at the base where hair originates in the dermis Surrounds hair papillae Only region of the hair containing living epithelial cells

Diploe

The spongy bone in the flat bones of the skull

Hair Matrix

The structure at the base of the hair bulb Epithelial cells divide here Produces new cells, which are gradually pushed toward the surface

Hyponechium

The thickened stratum corneum over which the free nail edge projects

Lunula

The whitish semilunar area on the proximal end of the nail body

Articular Cartilage

Thin layer of hyaline cartilage that covers the joint surface Reduces friction Absorbs shock in movable joints

Arrector Pili

Thin ribbons of smooth muscle Extend from hair follicle to dermal papillae Elevates hair with contraction, creating "goosebumps"

Stratum Granulosum

Third deepest layer of the epidermis 3-5 layers of keratinocytes Keratinocytes begin keratinization in this layer

Zone of Hypertrophic Cartilage

Third zone of the epiphyseal plate Chondrocytes cease dividing Cells greatly enlarge (hypertrophy) Walls of lacunae become thin

Epidermis

Top layer of the integument Composed of stratified squamous epithelium

Periosteum

Tough sheath covering the outer surface of bone An outer fibrous layer composed of dense irregular connective tissue Contains an inner cellular layer (includes osteoprogenitor cells, osteoblasts, and osteoclasts) Attached to bone by numerous collagen fibers (perforating fibers)

Hyaline Cartilage

Type of cartilage Attaches ribs to the sternum, covers the ends of some bones, is within growth plates, is a model for bone formation

Regeneration

Type of integumentary tissue repair Occurs after less-damaging injuries The replacement of damaged or dead cells with the same cell type Restores organ function

Fibrosis

Type of integumentary tissue repair Occurs after more-damaging injuries Gap is filled with scar tissue (collagen) Functional activities are not restored (glands, follicles, nerves are not repaired/replaced)

Carotene

Yellow-orange pigment acquired from some vegetables

Freckles

Yellowish or brown spots Localized areas of increased melanocyte activity

Root

Zone of hair from bulb to skin surface