exam 2 bio 203

5.1-8.1

integumentary system

integumentary system

consists of the skin, hair, nails, and their associated glands

skin

the bodies largest and heaviest organ

functions of the skin

barrier, resistance to trauma and infection, sensation.

vitamin D synthesis, thermoregulation

Epidermis

a keritinized stratified squamous epithelium. Consists of dead cells packed with tough protein keratin.

Lacks blood vessels

Keratinocytes

the majority of the epidermal cells, named for the role of synthesizing keratin

stem cells

undifferentiated cells that divide and give rise to keratinocytes.

Only found in the deepest layer of the epidermis

melanocytes

occur only in the stratum basale, synthesize melanin

Tactile cells

receptors for touch, found in the basal layer, associated with dermal nerve fibers

dendritic cells

found in two layers of the epidermis called the stratum spinosum and stratum granulosum. I

mmune cells that originate in the bone marrow but migrate to elsewhere.

stand guard against toxins, microbes, and other pathogens

Stratum basale

single layer of cuboidal to low columnar keratinocytes resting on the basement membrane

stratum spinosum

several layers of keratinocytes

Thickest layer of the stratum

Produces lots of keratin filaments that flatten as they are continuing to divide

cells appear flatter

Stratum granulosum

consists of three to five layers of flat keratinocytes more in thick skin

dark staining

stratum lucidum

thin zone that is superficial

seen only in thick skin

denesly packed keratinocytes with a clear protein eleidin

No nuclei or other organelles

pale, featureless appearance

stratum corneum

consists of up to 30 layers of dead, scaly keratinized cells

forms a durable surface layer

Resistant to abrasion, penetration, and water loss

epidermal water barrier

crucial to the retention of water

exfoliate

flaking off of dead cells in the form of dander from the epidermal surface

Dermis

deeper of the two layers of skin

Underlaying the epidermis

Composed of fibrous connective tissue

Dermal papilla

A bump or ridge of dermis that extends upward to interdigitate with the epidermis and create a wavy boundary that resists stress and slippage of the epidermis

Epidermal ridges

Downward epidermal waves between the papillae

Papillary layer

Thin zone of areolar tissue in and near the dermal papillae

Allows for the mobility of leukocytes and other defenses against organisms introduced through breaks in the epidermis

Rich in blood vessels

Reticular layer

deep and thick layer

Dense irregular connective tissue

More fibrous than cellular

Collagen forms thicker bundles with less room for ground substance, small clusters of adipocytes

Hypodermis

a layer of connective tissue deep to the skin

where drugs are introduced because it has subcutaneous tissue which is highly vascular and absorbs quickly

subcutaneous fat

hypodermis composed of adipose tissue

Serves as an energy reservoir and thermal insulation

Protects deeper tissue by absorbing pressure

Infants and older people have less of this tissue so they are more prone to be cold

Cyanosis

oxygen deficiency that causes a gray hue in the skin

Erythema

abnormal redness of the skin

Signs of inflammation or infection

Jaundice

Yellowing of the skin caused by an excessive concentration of bilirubin

Indicates liver disease, obstructed bile secretion, or hemolytic disease

Hematoma

a mass of clotted blood in the tissues

Accessory organ (appendages) of the skin

hair, nails, cutaneous glands

Composed of mostly dead keratinized cells

Pilus (hair)

slender filament of keratinized cells that grow from an oblique tube in the skin called a hair follicle

hair follicle

an epidermal pit that contains a hair and extends into the dermis or hypodermis

Downy hair (lanugo)

fine, unpigmented hair that appears on the fetus in the last 3 months of development

Vellus hair

constitutes for two thirds of hair on women

one tenth of hair on men

all of the hair on children

terminal hair

longer, coarser, and usually more heavily pigmented

Eyelashes, eyebrows, and scalp

Shaft of hair

portion of the hair above the skin

root

the portion of the hair bellow the surface

dermal papilla

A bump or ridge of dermis that extends upward to interdigitate with the epidermis and create a wavy boundary that resists stress and slippage of the epidermis

hair matrix

a region of mitotically active cells

the hairs growth center

medulla

tissue deep to the cortex of certain two layered organs such as the lymph nodes, adrenal glands, hairs, and kidneys

Cortex

the outer layer of some organs and covers the medulla

Cuticle

composed of multiple layers of thin scaly cells that overlap

Epithelial root sheath

Extension of the epidermis

Consists of stratified squamous epithelium and lies immediately adjacent to the hair root

apocrine sweat glands

occur in the groin, anal region, axilla, areola, and beard region

Thicker sweat because it contains more fatty acids

Eccrine sweat glands

widely distributed on the body

Mainly palms, soles, and forehead

Primary function to cool the body off

Myoepithelial

specialized cells that are found amid secretory cells

Have contractile properties

Sympathetic nervous system stimulates them to contract and force perspiration up the duct for conditions of overheating, nervousness, or arousal

Sebaceous glands

produce sebum and keep the hair from becoming brittle

Sebum

Oily secretion of the sebaceous glands that keep the skin and hair pliable

Ceruminous glands

modified apocrine glands found only in the external ear canal

Cerumen keeps the ear drum pliable, water proof, kills bacteria, and coats the guard hairs of the ear

Mammary glands

Milk producing glands

Modified apocrine glands that produce a richer secretion and channel it through ducts to a nipple for more efficient conveyance to the offspring

Lesions

A circumscribed zone of tissue injury

such as a skin abrasion

basal cell carcinoma

least deadly because it seldom metabolizes

Third degree burns/full thickness burns

all of the dermis and some deeper tissues are destroyed

Debridement

the removal of toxins from the respiratory tract

Functions of the skeleton

support, protection, movement, electrolyte balance, acid-base balance, blood formation, hormone secretion

osseous tissue

bone tissue

connective tissue in which the matrix is hardened by the decomposition of calcium phosphate and other minerals

mineralization/calcification

hardening of tissue due to the decomposition of calcium deposits

compact, dense, or cortical bone

outer shell of dense white osseous tissue

marrow (medullary) cavity

shell enclosed space

Hollow part of the bone that contains bone marrow

Spongy (cancellous) bone

loosely organized tissue

At the end of bones, occupies the central space

diaphysis

principal features of a long bone and its shaft

Provides leverage and is enlarged to provide strength for the joint

epiphysis

expanded head on each end of the long bone

articular cartilage

a thin layer of hyaline cartilage covering the articular surface of a bone at a synovial joint

Serves to reduce friction and ease joint movement

nutrient foramina

blood vessels penetrate into the bone through these minute holes

Periosteum

a layer of fibrous connective tissue covering the surface of a bone

Osteogenic cells

stem cells that develop from embryonic mesenchyme and then give rise to most other bone cell types

Osteoblasts

bone forming cells that synthesize the organic matter of the bone and then promote mineralization

Becomes an osteocyte

Osteocyte

former osteoblasts

embedded in the matrix and trapped in a lacunae

Lacunae

The small cavities that are in bone tissue

canaliculi

slender channels that interconnect lacunae cavities

Osteoclasts

bone dissolving cells on the surfaces of bones

Spicules and trabeculae

thin plate/layer of tissue that is a lattice of delicate slivers

Spongelike appearance even though it is calcified

Bone marrow

general term for the soft tissue that occupies the marrow cavity of a long bone, spaces amid the trabeculae of spongy bone, and larger canals

Red bone marrow (myeloid tissue)

nearly every bone is with with this

Hematopotetic tissue which produces blood cells

yellow bone marrow

red bone marrow is replaced by this in adults

Limited to the skull, vertebrae, ribs, sternum, part of the pelvic girdle

Yellow bone marrow no longer produces blood

intramembranous ossification

produces the flat bones of the skull, most clavicle, and part of the mandible

endochondral

is a process in which bone develops from a preexisting model composed of hyaline cartilage

appositional growth

bones grow in diameter and thickness

Deposition of a new tissue at the surface

Wolff’s law of bone

that architecture of a bone is determined by the mechanical stresses placed upon it, and the bone thereby adapts to withstand it

ectopic ossification

in an abnormal location such as an ectopic pregnancy

mineral deposition

is a crystallization process in which calcium, phosphate, and other ions, are taken from the blood plasma and deposited in the bone tissue, mainly as crystals

mineral resorption

is the process of dissolving bone

It releases minerals into the blood and makes them available for other uses

hypocalcemia

a calcium deficiency that causes excessive excitability in the nervous system

hypercalcemia

an excess of calcium ions in the blood

makes nerve cells less excitable

calcitriol

is a form of vitamin D produced by the sequential action of the skin, liver, and kidneys

Behaves as a hormone, blood borne chemical messenger from one organ to another

primary ossification center

chondrocytes begin to die while thin walls between them calcify

Osteoblasts start getting produced

primary marrow cavity

when blood vessels invade the primary ossification center, delivering blood borne osteoclasts that digest the calcified tissue creating a hollowed out center

metaphysis

the region of transition from cartilage to bone at the end of the primary marrow cavity

secondary ossification center

When chondrocyte enlargement and death happen this is created

epiphyseal plate

a plate of hyaline cartilage between the epiphysis and diaphysis of a long bone in a child serving as a growth zone for elongation

Calcitonin

produced by parafollicular cells of the thyroid gland

Lowers the blood calcium concentration when it raises too high

osteoclast inhibition

within 15 minutes of being secrete, calcitonin reduces osteoclast activity by as much as 70% so osteoclasts liberate less calcium from the skeleton

Osteoblast stimulation

within an hour, calcitonin increases the number and activity of osteoblasts which deposit calcium into the skeleton

Parathyroid hormone

a hormone secreted by the parathyroid glands that raises blood calcium concentration by stimulating bone resorption by osteoclasts, promoting intestinal absorption of calcium, and inhaling urinary excretion of calcium

stress fracture

break caused by abnormal trauma to a bone

pathological fracture

a break in a bone weakened by some other disease

steps to reforming a bone

1. Forming of hematoma and granulation tissue

2. formation of a soft callus

3. conversion to hard callus

4. remodeling

closed reduction

a procedure in which the bone fragments are manipulated into normal positions without surgery

open reduction and internal fixation (ORIF)

Involves surgically exposing the fractured bone and using plates, screws, or pins to realign the fragments

Appendicular skeleton

includes the bones of the upper limb and pectoral girdle and the pelvic girdle

axial skeleton

forms the central supporting axis of the body

includes the skull, auditory ossicles, hyoid bon, vertebral column, and thoracic cage

sesamoid bones

bones that form within some tendons in response to strain