Tissues and integumentary system

Four types of tissue

epithelial, connective, muscle, nervous

epithelial tissue

A body tissue that covers the surfaces of the body, inside and out. From boundaries

Epithelial Tissue Func.

Protection, absorption, Filtration, excretion, secretion, sensory reception

Epithelial Tissue Special Characteristics

1\.Two surfaces: Apical (unattached - borders open space) & Basal (attached to underlying connective tissue)

2\.Fit closely together to form continuous sheets (except glandular)

3\.All supported by connective tissue \n 4.Are avascular but innervated \n 5.Have high regenerative capacity (for repair)

simple epithelia

single layer of cells

stratified epithelia

two or more layers of cells that are stacked

Squamous

flat cells, scale like

Cubodial

cube shaped

Columnar

tall, column-like

naming layers for simple

naming layers for simple pic

simple squamous epithelium

Function: Allows passage of materials by diffusion and filtration in sites where protection is not important; secretes lubricating substances in serosae.

simple cuboidal epithelium

Function: secretion and absorption

simple columnar epithelium

Function: Absorption; secretion of mucus, enzymes, and other substances; ciliated type propels mucus (or reproductive cells) by ciliated action.

pseudostratified columnar epithelium

secretion and absorption

stratified squamous epithelium

Function: protects underlying tissues in areas subject to abrasion

transitional epithelium

function: stretches readily and permits distension of urinary organ by contained urine

glandular epithelium

Composed of cells that are specialized to produce and secrete substances.

endocrine glands

Ductless glands that empty their hormonal products directly into the blood

exocrine glands

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

connective tissue

A body tissue that provides support for the body and connects all of its parts. connective tissue, cartilage, bone, blood

Major Func. Connective Tissue

1. Binding and Support

2 protecting \n 3.insulating \n storing reserve fuel \n 5. Transporting substances

characteristics of connective tissue

variations in blood supply, extracellular matrix

ground substance

unstructured material that fills the space between the cells and contains the fibers

Connective tissue fibers

collagen, elastic, reticular

Fibroblasts & Fibrocytes

in connection tissue proper

Chondroblasts & Chondrocytes

in cartilage

osteoblasts & osteocytes

in bone

erythrocytes, leukocytes, platelets

blood

Other Cell Types in Connective Tissues

fat cells, white blood cells, mast cells, macrophages

connective tissue proper

all mature connective tissue except bone, cartilage and blood are connective tissue proper

loose connective tissue

areolar, adipose, reticular

functions: \n •Support and bind other tissues (fibers) \n •Holding body fluids (ground substance) \n •Defend against infection (WBCs and macrophages) \n •Store nutrients (fat in fat cells)

dense connective tissues

dense regular, dense irregular, elastic

connective tissue proper: loose, areolar

Wraps and cushions organs; macrophages phagocytize bacteria; plays and important role in inflammation; holds and conveys tissue fluid. Widely distributed under epithelia of body, forms lamina propria of mucous membranes; packages organs, and surrounds capillaries

connective tissue proper: loose, adipose

Provides reserve food fuel; insulates against heat loss; supports and protects organs. Found under the skin in subcutaneous tissue, around kidneys and eyeballs, within the abdomen and breast. White fat, Brown fat

connective tissue proper: loose, reticular

Description: Network of reticular fibers in a typical loose ground substance; reticular cells lie on the network

Function: Fibers form a soft internal skeleton (stroma) that supports other cell types including white blood cells, mast cells, and macrophages

Connective Tissue Proper: Dense, Regular

Closely packed bundles of collagen fibers running parallel to direction of pull \n Resistant to tension \n Few cells \n Poorly vascularized \*\* Important to consider healing time \*\*

Connective Tissue Proper: Dense, Irregular

Same structural elements as regular but bundles of collagen thicker and irregularly arranged

Resists tension from many directions

Forms sheets in body

Connective Tissue Proper: Dense, Elastic

some ligaments very elastic, a type of dense regular tissue

Cartilage

A connective tissue that is more flexible than bone and that protects the ends of bones and keeps them from rubbing together.

Cartilage: Hyaline

Function: supports and reinforces

Location: forms most of the embryonic skeleton

Cartilage: Elastic

•Nearly identical to hyaline cartilage in structure but has more elastic fibers

•Strength and stretch

Cartilage: fibrocartilage

rows of chondrocytes and rows of collagen fibers alternating

Resists compression and tension - found where support is needed to withstand heavy pressure

bone

Dense, hard connective tissue composing the skeleton

blood

Description: red and white blood cells in a fluid matrix (plasma)

Function: Transport of respiratory gases, nutrients, wastes, and other substances

Location: contained within blood vessels

muscle tissue

highly vascularized, responsible for most types of movement

skeletal muscle

a muscle that is connected to the skeleton to form part of the mechanical system that moves the limbs and other parts of the body.

cardiac muscle

involuntary-propels blood into circulation

smooth muscle

involuntary muscle found in internal organs

nervous tissue

Tissue that senses stimuli and transmits signals.

Tissue Repair Step 1: inflammation

release of inflammatory chemical cause dilation of blood vessels and increases in blood vessel permeability

Clotting of blood occurs

Tissue Repair Step 2: Organization restores blood supply

\-The blood cot is replaced with granulation tissue

\-Epithelium begins to regenerate \n -Fibroblasts produce collagen fibers to bridge the gap \n -Debris is phagocytized

Tissue Repair Step 3: Regeneration and Fibrosis

The scab detaches, Fibrous tissue matures; epithelium thickens and begins to resemble adjacent tissue, Results in a fully regenerated epithelium with underlying scar tissue

regenerative capacity of tissues

•Good: Epithelial, bone, areolar connective tissue, dense irregular connective tissue, and blood-forming tissue

•Moderate: Smooth muscle and dense regular connective tissue \n •Weak: Skeletal muscle and cartilage \n •Virtually none: Cardiac muscle and nervous tissue in brain and spinal cord

Developmental Aspects of Embryonic Tissues

•Primary germ layers (primary layer of cells that form in embryonic development)•Superficial to deep: ectoderm, mesoderm, and endoderm

Aging Tissues

cells divide more slowly as people age and injuries heal more slowly

extracellular matrix containing collagen and elastic fibers become less flexible and less elastic consequently skin wrinkles; and elasticity in arteries is reduced; and bones break more easily

Epidermis

most superficial layer of skin

Dermis

Inner layer of skin; vascularized

Hypodermis

Aso called a subcutaneous layer, this is a layer of *fat located under the dermis of the skin. The hypodermis helps to insulate the body and protects underlying muscles and other structures.

Cells of the Epidermis

keratinocytes, melanocytes, dendritic cells, tactile cells

layers of epidermis

stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

stratum basale

the deepest layer of the epidermis consisting of stem cells capable of undergoing cell division to form new cells

stratum spinosum

several layers thick; abundant melanosomes and dendritic cells.

statum granulosum (granular layer)

•Thin layer - one to five cell layers \n •Keratinization begins - Keratinocytes begin to flatten and fill with keratin \n •Cells above this layer die \n -Too far from dermal capillaries and glycolipid coating cuts off from nutrients

Stratum lucidum (clear layer)

Only in thick skin

Thin, translucent band superficial to the stratum granulosum

A few rows of flat, dead keratinocytes

Stratum corneum (horny layer)

The outermost layer consisting of 20-30 layers of dead, scalelike keratinocytes. They are constantly being exfoliated and replaced by the division of the deeper cells. nearly waterproof

papillary layer (dermis)

upper layer of the dermis that forms dermal papillae

reticular layer (dermis)

dense irregular connective tissue

Melanin

A pigment that gives the skin its color

Carotene and Hemoglobin

Carotene

Yellow to orange pigment Most obvious in palms and soles Accumulates in stratum corneum and hypodermis Can be converted to vitamin A for vision and epidermal health Yellowish-tinge of some Asians - carotene and melanin variations Hemoglobin Pinkish hue of fair skin

cyanosis

bluish discoloration of the skin

pallor

an extreme or unnatural paleness

erythema

redness of the skin

jaundice

yellowing of the skin and the whites of the eyes caused by an accumulation of bile pigment (bilirubin) in the blood

ecchymoses

larger blue or purplish patches on the skin (bruises)

Brown or black "necklace" or bruises

Dark areas in the axillae and around the neck are sometimes mistaken for a lack of cleanliness. These areas of velvety hyperpigmentation may be a sign of insulin resistance and elevated blood glucose.

Appendages of the skin

Hair, nails, sweat glands, and oil glands

Hair (pili)

flexible strands produced by hair follicles and consist largely of dead, keratinized cells

hair texture

Thickness or diameter of the individual hair strand

vellus hair

peach fuzz

terminal hair

coarse, long hair of eyebrows, scalp, axillary, and pubic regions

eccrine sweat glands

found in palms, soles of the feet, and forehead

apocrine sweat glands

Found in armpits, around nipples, and groin; Secrete products into hair follicles; Produce sticky, cloudy secretions; Break down and cause odors;

Sebaceous (oil) glands

Produce sebum to keep skin and hair soft, and prevent bacteria from growing on the skin

functions of integumentary system

1. Protection

2\. Body Temperature Regulation \n 3. Cutaneous Sensation \n 4. Metabolic Functions \n 5. Blood Reservoir \n 6. Excretion

three types of barriers

chemical, physical, biological

insensible perspiration

sweat that evaporates from the skin before it is perceived as moisture

sensible perspiration

dilation of dermal vessels

blood reservoir

up to 5% of body's blood volume

basal cell carcinoma

Most common and least severe type of skin cancer; often characterized by light or pearly nodules.

squamous cell carcinoma

Type of skin cancer more serious than basal cell carcinoma; often characterized by scaly red papules or nodules.

Melanoma

The most serious form of skin cancer

ABCD rule

asymmetry, border irregularity, color, diameter

Evaluating burns

Rule of nines, and used to estimate volume of fluid losed.

Head and neck burns cover what % of body?

9

upper limbs burns cover what % of the body?

18%

perineum burns cover what % of body?

1%

Lower limb burns cover what % of body?

36%

first degree burn

Superficial burns through only the epidermis. localized redness, edema, and pain

second degree burn

A partial-thickness burn involving the epidermis and the dermis. blisters

third degree burn

involves destruction of epidermis, dermis and subcutaneous layer. •Skin gray-white, cherry red, or blackened

•Burned area is not painful (nerve endings destroyed)

Skin grafting usually necessary