A&P , Exam 2 ( Integument, Physiology of bone, Articulations)

Integument

covering of the body (skin)

Epidermis

outermost layer of skin, avascular

Dermis

Underlies epidermis, fibrous connective tissue, vascular

Hypodermis (superficial fascia) (subcutaneous tissue)

Subcutaneous layer deep to skin

Not part of skin but shares some functions

Mostly adipose tissue that absorbs shock and insulates

Consist of adipose/areolar connective tissue

Anchors skin to underlying structures: mostly muscles

Keratinocytes

Major cell in epidermis, produce fibrous keratin

Keratin

hard protein material found in the epidermis, hair, and nails ( gives skin its protective properties)

Melanocytes

cells that produce melanin

Melanin

A pigment that gives the skin its color

Dendritic cells

activate the immune system
(Star-shaped macrophages deep in epidermis)

Tactile (Merkel) cells

sensory receptors that sense touch

stratum basale (stratum germinativum)

Deepest layer
Stem cells that actively divide (mitotic)

stratum spinosum ( prickly layer)

Several cell layers thick, cells contain a weblike system of intermediate prekeratin filaments attached to desmosomes. Keratinocytes appear to have spines and are scattered among abundant melanin granules and Langerhans' cells.

stratum granulosum

4-6 cells thick, keratinization begins

Help form keratin fibers in upper layer

Lamellar granules- water-resistant glycolipid slows water loss

Stratum lucidum (clear layer)

Only in thick skin; a few rows of flat dead keratinocytes

stratum corneum

outermost layer of the epidermis, which consists of flattened, keratinized cells
( protective barrier) prevent water loss, protect deeper cells from the environment

Papillary layer of Dermis

Superficial layer of the dermis, composed of areolar connective tissue

Dermal papillae- superficial region of dermis, sends finger like projections to epidermis

(Friction ridges)

reticular layer of dermis

dense irregular connective tissue

Cleavage (tension) lines- collagen fibers running parallel to skin

Flexure lines- reticular layer ( dermal folds/ near joints)

Carotene

yellow to orange pigment, most obvious in the palms and soles of the feet
(Converted for vitamin a for vision)

Hemoglobin

Pinkish hue of fair skin is due to lower levels of melanin

Skin of Caucasians is more transparent, so color of hemoglobin shows through

Epidermal appendages

hair, sebaceous glands, sweat glands (eccrine and apocrine), nails

Hair

Made of keratin.
Warm on insect skin
Hair on head guards against physical trauma
Protect from heat loss
Shield skin from sunlight
(Hair-pili (flexible strands of dead cells)
(Also called pili)

Nail

Contain hard keratin
Protective cover for distal, dorsal surface for fingers and toes

exocrine glands

secrete chemical substances into ducts that lead either to other organs or out of the body

sudoriferous glands

sweat glands

Eccrine (merocrine) sweat glands

Functions in thermoregulation
Abundant on palms, soles and forehead

apocrine sweat glands

found in axillary and anogenital areas
Begins at puberty
Milky or yellowish sweat ( fatty substances/protein)

ceruminous glands ( type of apocrine)

Lining external ear canal ( secrete cerumen (earwax)

Mammary glands

secrete milk

Sebaceous glands (holocrine secretion)

secrete sebum (oil) into the hair follicles where the hair shafts pass through the dermis
Bactericidal (bacteria-killing properties)

Tactile (messiner's) corpuscles

Sensory receptors located in dermal papillae of skin ( receptors for touch/light touch)

Pacinian corpuscles (lamellar)

respond to deep pressure and vibration

benign tumor

Not cancerous/ don't spread (metastasize)

Malignant tumor

Cancerous tumor

Hyperplasia

increase in number of cells in organ or tissue but is normal under a microscope

metastasis

The spread of cancer cells to locations distant from their original site.

basal cell carcinoma

Least malignant and most common, involves cells of the stratum basale

sqaumous cell carcinoma

The second most common skin cancer, arises from keratinocytes of stratum spinosum
(Scaly red on scalp, ears, lower lips, or hands

Melanoma

cancer of melanocytes, highly metastatic/ resistant to chemotherapy
(Asymmetry, irregular border, color, diameter- larger than 6 mm)

first degree burn

only epidermis is damaged

( redness, edema (swelling), and pain

(Partial-thickness burns)

Second-degree

epidermal and upper dermal damage; blisters appear

(Partial-thickness burns)

Third-degree

(Full-thickness burns)

Skin- gray-white, cherry-red, or blackened

(Nerve endings are destroyed

(Skin-grafting is necessary)

Cartilage

A connective tissue that is more flexible than bone and that protects the ends of bones and keeps them from rubbing together.
(Made up of chrondocytes- cell encased in small cavities (lacunae- w/in a extracellular matrix)

Perichondrium

membrane that covers cartilage ( dense connective tissue)
Helps cartilage resist outward expansion
Contains blood vessels for nutrient delivery to cartilage

Hyaline Cartilage

The most abundant cartilage type, contains collagen fibers only
(Provides support, flexibility and resilience)
Articular (joints), costal (ribs), respiratory (larynx), nasal cartilage (nose tip)

Cartilage grows- appositional growth

Cartilage-forming cells in perichondrium secrete matrix against external face of existing cartilage

Cartilage grows- interstitial growth

Chondrocytes w/in lacunae divide and secrete new matrix ( cartilage from w/in)

elastic cartilage

external ear, epiglottis ( similar to hyaline but contains elastic fibers)

Fibrocartilage

Thick collagen fibers ( great tensile strength)
Ex- menisci of knee/vertebral discs

endoskeleton

internal skeleton

axial skeleton

skull, vertebral column, rib cage ( axis of body)

appendicular skeleton

Bones of upper/ lower limbs
Girdles attach limbs to axial skeleton

pectoral girdle (shoulder girdle)

Bones that attach the upper limbs to the axial skeleton; includes the clavicle and scapula

pelvic girdle (hip girdle)

Consists of paired hip bones and sacrum that attach to lower limbs to axial skeleton

Compact bone

external layer of bone ( dense/smooth and solid)

Spongy bone

Internal layer of skeletal ( trabecular bone)

Periosteum

covers outside of compact bone
(White doubled layer, membrane that covers external surfaces except joints)

Endosteum

covers inside portion of compact bone
( delicate connective tissue covers internal bone surface)
Lines canals that pass through compact bone

Mesenchyme

embryonic connective tissue

Osteopeogenitor (osteogenic) cells

Stem cells that develop into osteoblasts that produce matrix of bone
Give rise to most/ all bone cells

Osteoblasts

bone-forming cells that secrete the bone matrix

Osteocytes

mature bone cells in lacunae that no longer divide

Osteoclasts

Bone-destroying cells, bone remodeling occur

Osteon

structural unit of compact bone

fibrous periosteum

outer layer of covering over bone - ligaments and tendons attach here

Osteogenic periosteum

The inner osteogenic layer of the
periosteum

Lacuna

small cavities in bone that contain osteocytes

Canaliculus

a small channel or duct.
Canaliculi- hairlike canals that connect lacunae to each other and to central canal

Volkmann's canals (perforating)

Canals lined w/ endosteum that occur at right angles to central canal
(Connects blood vessels and nerves of periosteum, medullary cavity and central canal)

Osteoid

unmineralized bone matrix
(Made up of collagen/calcium-binding proteins)

Proteoglycans

a glycoprotein consisting of a small core protein with many carbohydrate chains attached, found in the extracellular matrix of animal cells.

hydroxapatites (mineral salts)

Inorganic compound
(Calcium phosphate crystals)

Ossification (osteogenesis)

bone tissue formation

intramembranous ossification

bone develops from a fibrous membrane
( bone- membrane bone)
(Formed by mesenchymal cells)

primary center of ossification

In center of shaft ( diaphysis)
Where bone first forms

secondary center of ossification

Epiphysis, Area of bone development, usually near the end of a long bone. After birth.

Epiphysis

End of a long bone

Diaphysis

shaft of a long bone

epiphyseal plate

Growth plate, made of cartilage, gradually ossifies
(Resting zone (quiescent zone)proliferation (growth zone) hypertrophic zone, calcification zone, ossification (osteogenic zone

Bone remodeling

bone deposit and bone resorption occur at the surfaces of both the periosteum and the endosteum
(Process of bone formation/ destruction in response to hormonal and mechanical factors)

Resorption vs ossification

Resorption- function of osteoclasts ( removal of osseous tissue... bone remodeling process)
Ossification-new bone tissue ( osteoblasts)

parathyroid hormone (PTH)

raises blood calcium level when it's low until equilibrium is reached ( hormone released by parathyroid gland- regulates blood calcium level)

Wolff's Law

A bone grows or remodels in response to forces or demands placed upon it

fracture treatment/repair

1. Hematoma formation
2. Fibrocartilaginous callus
3. Bony callus
4. Remodelling

Hematoma

a solid swelling of clotted blood within the tissues.

Fibrocartilage callus- mass of repair tissue

a temporary formation of fibroblasts and chondroblasts which forms at the area of a bone fracture as the bone attempts to heal itself
(Create cartilage matrix of repair tissue/osteoblasts form spongy bone w/in matrix)

bony callus formation

Hard thickened area of immature bone that repairs the fibrocartilaginous callus during fracture repair

Bony hard callus of spongy bone

Osteomalacia

Soft, weak bones
Bones are poorly mineralized
Osteoid is produced but calcium salts not deposited
Pain upon bearing weight

Osteoporosis

Bone resorption exceeds deposit
Matrix is normal, bone mass declines

Articulation

joint ( where 2 or more bones meet)

Synarthroses (Fibrous Joints)

immovable joints

Amphiarthroses (Cartilaginous Joints)

Slightly movable joints

Diarthoses or ( synovial joints)

Freely movable joints

fibrous joints

generally immovable ( joined by dense fibrous connective tissue)
Types- sutures, syndesmoses, gomphoses

Sutures (fibrous joint)

immovable joints of the skull
(Synostoses closed/ immovable sutures)

syndesmoses (fibrous)

bones connected by ligaments
Ex- (short- no movement inferior tibiofibular joint)
Ex- long larger movement , interossesous membrane connecting radius/ulna

Gomphoses (fibrous) immovable

peg-in-socket joint (teeth)
(Periodontal ligament)

cartilaginous joints

Bones held together by cartilage; no joint cavity

synchondrosis (cartilaginous joint) almost all synarthrotic (immovable )

a functional classification of joints in which the connecting material is hyaline cartilage
Ex- temporary epiphyseal plate joints

Symphyses (cartilaginous)- slightly movable

Bones united by fibrocartilage ( in symphysis joint)
Ex- pubic symphysis/ intervertebral joints

synovial joints (diarthrotoc- freely movable)

bones separated by fluid-filled joint cavity