anatomy and physiology Exam 2

sheet of cells that covers body surfaces or cavities

Two main forms:

• covering and lining epithelia

  • on external and internal surfaces

• Glandular epithelia

  • secretory tissue in glands

main functions: protection, absorption, filtration, excretion, secretion, and sensory reception

epithelial tissue

Polarity-

Apical surface, upper free side, is exposed to surface or cavity

• most apical surfaces are smooth, but some have specialized fingerlike projections called microvilli

basal surface, lower attached side, faces inwards towards body

• attaches to basal lamina, an adhesive sheet that holds basal surface of epithelial cells to underlying cells

special characteristics of epithelial cells

only has one layer of cells

simple epithelial tissue

has multiple layer of cells

stratified epithelial tissue

Most abundant tissue and widely distributed of primary tissues

Major functions: binding and supporting, protecting, insulating, storing reserve fuel, and transporting substances (blood)

consist of four main classes:

• Connective tissue paper

• cartilage

• bone

• blood

connective tissue

function: allows materials to pass by diffusion and filtration in sites where protection is not important, secretes lubricating substances in serosae

location: kidney glomeruli; airs sacs in lungs; lining of heart; blood vessels; and lymphatic vessels; serosae

simple squamous epithelium

conciliated type lines and most of the digestive tract (stomach to rectum), gallbladder, and excretory ducts of some glands; ciliated variety lines small bronchi

simple columnar epithelial tissue

can be found in the trachea and most upper respiratory tract, conciliated type in males sperm-carrying ducts and ducts of large glands

pseudostratified columnar epithelium

what special cell type is in simple columnar?

Goblet cell

what special cells are found in stratified squamous epithelial

keratinocytes

what cells are found transitional epithelial

basal cells

immature form of cell that actively secretes ground substance and fibers

“blasts” cells

found in connective tissue proper

fibroblasts

found in cartilage

chondroblasts

found in bone

osteoblasts

mature, less active form of “blasts” cell that now becomes part of and helps maintain health of matrix

“cyte” cells

stores nutrients (fat cells)

adipocytes

phagocytic cells that “eat” dead cells, microorganisms, function in immune system

macrophages

All 3 are composed of ground substance, fibers, and cells

3 things that connective tissue have in common

found in lymphoid organs (lymph nodes, bone marrow, and spleen)

loose reticular connective tissue

found in large wall of arteries; within certain ligaments associated with the vertebral column; within the walls of the bronchial tubes

proper dense elastic connective tissue

function: most abundant cartilage, providing firm support with some flexibility

location: ends of long bone, tip of nose, trachea and larynx

Hyaline cartilage

function: where strong support and the ability to withstand heavy pressure are required

location: invertebral discs

fibrocartilage cartilage

function: where strength and exceptional stretch are needed (maintain shape)

location: external ear and epiglottis

elastic cartilage

function: support and protect the body structures due to its hardness

location: outside of bone

has lacuna

compact bone

function: makes new red blood cells

location: found inside the bone

spongy bone

found in blood: red blood cell (erythrocyte) and lymphocyte neutrophil

function: transportation

blood connective tissue

glands are ductless glands that secrete hormones by exocytosis directly into blood or lymph

endocrine

glands have ducts and secrete their product onto a surface or into body cavities

exocrine

function: attaches to the skeleton and is composed of long and cylindrical cells

voluntary

location: all over body

skeletal muscle tissue

striated, uninucleate, branches, and are located only in the heart

involuntary - Intercalated discs

cardiac muscle tissue

function: non-striated, small, and spindle-shaped

involuntary

location: found in walls of hallow organs

smooth muscle tissue

specialized cells that have processes that allow them to respond to stimuli and generate and conduct electrical impulses

neuron

supporting cells that protect the neurons

gilal cells

epithelial, bone, areolar, dense, irregular

what tissues are regenerative

produce fibrous keratin (protein that gives skin its protective properties)

main cell type of epidermis, tightly packed, slough off

keratinocytes

in deepest of epidermis

produces pigment (melanin), which is packed into melanosomes

melanocytes

star shapes macrophages that are part of immune system

dendritic (langerhan) cells

sensory receptors that sense touch

tactile cells

deepest layer of all epidermal layers (base layer)

firmly attached to dermis, consist of a single row of stem cells that actively divide (mitotic) producing two daughter cells each time

mostly made up of keratinocytes

stratum basale (basal layer)

several cell layers thick

cells contain weblike system of intermediate pre keratin filaments attached to the desmosomes

keratinocytes in this layer appear prickly, abundant in melanomas and dendritic cells

stratum spinosum

four to six cells thick, cells are flattened, layer is thin

keratinization begins

cells above this layer dies

stratum granulosum

found only in thick skin, thin and translucent band of two or three rows of clear, flat, dead keratinocytes

filled with eleidin

stratum lucidum

20-30 rows flat, nucleated, keratinized deal cells

through the dead, cells can still protect deeper cells from environment, prevent water loss, protect from abrasion and penetration, act as a barrier biological, chemical, and physical assaults

stratum corneum

keratinized stratified squamous epithelial tissue

what tissue makes up the epidermis

thick skin has the stratum lucidum

thick skin vs. thin skin

superficial layer of areolar connective tissue

loose fibers allow phagocytes to patrol for microorganisms

superficial region of dermis that sends fingerlike projections into epidermis

dermis: papillary layer

consist of dense irregular connective tissue

• bind water to keep skin hydrated

extracellular matrix contains pockets of adipose tissue

dermis: reticular layer

strong, flexible connective tissue

contains nerves, blood vessels, and lymphatic vessels

keeps foreign objects out of body

functions of the skin

reticular layer are caused by many collagen fibers running parallel to skin surface

cleavage lines

reticular layer are dermal folds at or near joints

flexure lines

in thick skin, dermal papillae lie on top of dermal ridges, which gives it a rise to epidermal ridges

friction ridges

melanin, carotene, and hemoglobin

normal skin pigment

cyanosis, pallor, erythema, and jaundice

abnormal skin pigments

sweat glands

eccrine glands

modified procaine glands (smelly)

apocrine glands

secretes sebum, lubricates the skin and hair, prevents water loss, antibacterial properties

sebaceous glands

secretes milk

mammary glands

• least malignant and most common

• stratum basale cells proliferate and slowly invade dermis and hypodermis

• cured by surgical excision in 99% of cases

basal cell carcinoma

• second most common type; can metasize

• involves keratinocytes of stratum spinosum

• usually is scaly reddened papule on scalp, ears, lower lip, or hands

• good prognosis if treated by radiation therapy or removed surgically

squamous cell carcinoma

cancer of melanocytes; most dangerous type because it is highly metastatic and resistant to chemo

• treated by wide surgical excursion accompanied by immunotherapy

• use ABCD rule

melanoma

epidermal damage only

first degree burn

epidermal and upper dermal damage

• blisters appear

• also called partial-thickness burns

second degree burn

all layers damaged

• not painful because nerves are destroyed

• full thickness burns

third degree burns

epidermal replacement slows, skin becomes thin, dry, and itchy

subcutaneous fat and elasticity decrease, leading to cold tolerance and wrinkles

increased cancer risk due to decreased number of melanocytes and dendritic cells

aging affecting skin

thickened portion of bed responsible for nail growth

nail matrix

actively dividing area of bulb that produces hair

hair matrix

provides structural framework for your body

function of bones

bones that are longer than they are wide

long bones

bones that are as long as they are wide making a cube

short bones

bones that have complicated shapes

irregular bone

bones that are thin and sometimes curved at the edges

flat bones

bones that are embedded in tendons

sesamoid bones

• elongated, usually cylindrical shaft

• provides leverage and weight support

• compact bone with spongy bone extending inward

diaphysis

• hollow, cylindrical space within diaphysis

• contains red bone marrow in children

• contains yellow bone marrow in adults

medullary cavity

knobby region at each end of long bone

epiphysis

• covers the joint surface

• thin layer of hyaline cartilage

• reduces friction

• absorbs shock in moveable joints

articular cartilage

• in metaphysis

• growth plate

• thin layer of hyaline cartilage

• provides lengthwise bone growth

• In adults the epiphyseal plate is the remnant of the epiphyseal line

epiphyseal plate

white, double layered membrane that covers external surfaces except joints

periosteum

delicate connective tissue membrane covering internal bone surfaces

endosteum

bone forming cells that secrete unmineralized bone matrix called osteoid

osteoblasts

mature bone cells in lacunae that no longer divide

osteocytes

flat cells on bone surfaces believed to also help maintain matrix

bone lining cells

derived from the same hematopoietic stem cells that become macrophages

osteoclasts

long bones grow lengthwise by interstitial growth of epiphyseal plate

interstitial growth

growing bones widen as they lengthen through

appositional growth

The basic structural unit of compact bone made of concentric lamellae surrounding a central canal.

What is an osteon (Haversian system)?

It contains blood vessels, nerves, and lymphatic vessels that nourish bone tissue.

What is the function of the central (Haversian) canal?

Concentric rings of bone matrix that surround the central canal and provide strength.

What are lamellae?

Small spaces between lamellae that contain osteocytes.

What are lacunae?

Mature bone cells that maintain bone tissue.

What are osteocytes?

Canals that run perpendicular to central canals and connect blood vessels between osteons.

What are Volkmann's (perforating) canals?

What part of bone provides flexibility?

The organic portion, mainly collagen fibers.

What part of bone provides hardness and strength?

The inorganic portion, mainly calcium phosphate (hydroxyapatite) crystals.

Which component of bone is collagen responsible for?

Flexibility

Which component of bone is calcium responsible for?

Hardness and strength.

What does growth hormone (GH) do?

Stimulates cartilage growth at growth plates and increases bone length and thickness.

Which gland produces growth hormone?

The pituitary gland.

What happens if there is too little growth hormone during childhood?

Pituitary dwarfism.

What happens if there is too much growth hormone during childhood?

Gigantism