lecture exam 2 Flashcards
the thin tissue forming the outer layer of a body’s surface and lining the alimentary canal and other hollow structures
epithelium
characteristics of epithelium
widespread- covers most of the body, inside and out.
- always has a free surface
- epithelial tissues usually lack a direct blood supply
- capable of mitosis
- cells usually packed tight, little intercellular material
- function in abosrption, secretion, and/or protecyion; usually highly inverted
membraneous epithelium are classified by _______,______,_____
shape, arrangement, function
singe layer of thin skin, flattened cells.
found where substaces need to move easily across a membrane (air sacs of lungs, walls of capallaries, bowmans capsule of kidneys)
simple squamos epithelium
single layer of cube-shaped cells.
found lining small ducts/tubeles that may have excretory, secretory, or absorptive functions (surface of ovaries, lining of smaller salivary gland, and sweat glands)
simple cubodial epithlium
single layer of elongated cells, with nucleus usually deep in the cell, near basement membrane
simple columnar epithelium
Found in the linings of uterus and uterine tubes and various organs of thedigestive tract (i.e., stomach, intestines, gall bladder), collecting ducts of kidneys
simple columnar epithelium
May be equipped with microvilli on free surface to increase absorptive properties, plus goblet cells, which secrete mucus onto free surface; or, with goblet cells and cilia on free surface to move fluids or particles along a passageway
simple columnar epithelium
A: Single layer of columnar epithelium in which cell nucleus is located at any level within the cell, not necessarily next to the basement membrane; all cells are anchored to thebasement membrane, but not all reach the free surface
b. Found in linings of upper respiratory system and lining some tubes of the male reproductive tract
c. May possess cilia and mucus-secreting goblet cells which facilitatetransport of material from one place to another
pseudostratified epithelium
a. Multiple layers of epithelial cells, of which the cells near the free surface are squamosal (i.e., thin and flattened); deeper layers tend to be cuboidal or columnar
b. Keratinized vs. non-keratinized
c. Makes upthe epidermis of the skin (keratinized), lines oral cavity, throat, esophagus, vagina, and anal canal (non-keratinized); mainly protective in function
startified squamos epithelium
a. Two-to-three layers of cuboidal epithelial cells, forming lining around a lumen
b. Limited to linings of larger glandular ducts (i.e., sweat glands, salivary glands, and pancreas); mainly protective in function
staratified cubodial epithelium
a. Several layers of cells, with columnar cells atthe free surface and cuboidal cells at the basement membrane
b. Found in parts of the pharynx and parts of the male urethra and ductusdeferens; mainly protective in function
stratified columnar epithelium
a. Consists of several layers of cuboidal cells, specialized to permit stretching and recoil
b. Forms inner lining of urinary bladder and part of ureters and urethra,adjacent to bladder
transitional epithellium
composed of epithelial cells specialized to produce and secrete substances into ducts or body fluids; usually located within, or composed of,columnar or cuboidal epithelium
glandular epithelium
secrete products (i.e., hormones) directly into tissue fluid; highly vascularized
endocrine glands
secrete products into ducts that open onto internal or external surfaces
Exocrine glands:
Unicellular (e.g., goblet cells)
ii.Multicellular
a.Duct shape: simple or compound
b’.Secretory structure shape: tubular or alveolar (i.e., sac-like)
types of exocrine glands
Merocrine: releases fluid cellular products through cell membranes without loss of cytoplasm (e.g., salivary glands)
a. Mucous membranes and mucus fluid
b. Serous membranes and serous fluid
types of secretions
ii. Apocrine: loses small portions of cell bodies during secretion (e.g., mammary glands)
iii. Holocrine: releases contents of entire cells filled with secretory products (e.g., sebaceous glands of skin)
types of secretions
A.Function: support/bind/protect other tissues/structures
B.General characteristics
1.Highly vascularized (except cartilageand dense regular connective tissue)
2.Cells capable of replication
3.Is not found on the free surfaces of body cavities or on body surface
4.Cells typically spaced far apart, with intervening space filled by an extracellular matrix
connective tissue
and osteocytes: responsible for secretion and maintenance of bone tissue matrix
Osteoblasts
secrete fibrous proteins into surrounding intercellular ground substance
Fibroblasts
specialized for fat storage
Adipocytes
responsible for secretion and maintenance of cartilage matrix
Chondroblasts and chondrocytes:
structural cells in connective tissue composed of _____, _____, ______, _____.
osteoblasts, fibroblasts, adipocytes, chondroblatst
I.Macrophagesand microphages: specialized to engulf and destroy foreign and damaged cells
ii. Mast cells: relatively large cells with many vesicles; release substances important for defense against foreign cells and particles
iii. Plasma cells: modified leukocytes which produce antibodies
defensive cells
consists of ground substance +fibers
Matrix:
composed of the protein collagen; strong, resistant to stretch, flexible
Collagen fibers:
capable of stretch and recoil; composed of the protein elastin
Elastic fibers:
very thin collagen fibers, forming delicate supporting meshes within tissue
Reticular fibers:
amorphous substance within which cells and fibers are embedded
Ground substance:
(ground substance is gel-like in consistency)
Connective tissue proper
(aka, areolar): thin, delicate membranes with collagen, elastic, and reticular fibers(e.g., space between muscles, underlying epithelial tissue)
Loose connective tissue
specialized form of loose connective tissue; adipocytes store fat droplets within cells(e.g., protective cushion, energy storage)
Adipose:
fine reticular fibers arranged in three-dimensional network(e.g., spleen and liver, bone marrow, lymph nodes)
Reticular connective tissue:
high concentration of collagen fibers; regular (e.g., tendons & ligaments) vs. irregular (e.g., reticular layer of dermis,periosteum, epimysium, epineurium)
Dense (aka, fibrous) connective tissue:
elastic fibers arranged in parallel strands or branching networks(e.g., artery walls, large respiratory passages
Elastic connective tissue:
tissue(ground substance is rigid or semi-rigid)
Supporting connective
semi-rigid connective tissue; matrix has a high concentration of fibers
Cartilage:
fine collagenfibers within a semi-rigid ground substance (e.g., parts of larynx, nose, articular cartilages, costal cartilages, epiphyseal plates/discs)
Hyaline cartilage:
high concentration of elastic fiberswithin a semi-rigid ground substance(e.g., external ear, partsof larynx)
Elastic cartilage:
network of large collagen fibers, embedded within a less rigid ground substance(e.g., pubic symphysis, intervertebral disks)
Fibrocartilage:
rigid connective tissue with a mineralized matrix
Bone tissue:
(ground substance is a liquid)
Fluid connective tissue
matrix consists only of fluid ground substance (i.e., plasma) with no fibers
Blood:
an organ within the integumentary system
Skin (aka, integument):
composed of skin+ accessory organs (nails, hair, glands, nerve endings, etc.)
Integumentary system:
Protective covering
B.Regulation of body temperature
1.Retains internal body heat via subcutaneous layer
2.When necessary, eliminates excessive body heat
Housing of sensory receptors
D.Synthesis of various chemicals (e.g., keratin, melanin, vitamin D)
E.Excretion of waste materials (by means of perspiration)
Function of integumentary system
keratinized stratified squamous epithelium
Epidermis:
structure of skin from deepest to superficial
stratum basale stratum spinosum stratum granulosum lucidum corneum
Composed of connective tissue, and housing muscle fibers, blood vessels, hair follicles, exocrine glands, and sensory nerve fibers
dermis
loose connective tissue directly underlying the epidermisi.
Dermal ridges (such as fingerprints) due to the pulling of elastic fibers in the papillary layer; only associated with thick skin of hands and feet
papillary layer
dense irregular connective tissue underlying the papillary layer
i.Quite distensible and resilient; when over-stretched, it tears, producing ‘stretch marks
Reticular layer:
loose connective tissue and adipose tissue interlaced with blood vessels
Subcutaneous layer (aka, hypodermis):
serves as heat insulator and energy reservoir
Adipose tissue
a.Conserves internal body heat or impedes entrance of external heat
b. Distribution of subcutaneous adiposetissuevaries throughout the body and between the sexes (generally 8% thicker in women than in men)
c. Thickness of subcutaneous layer can be indicative of nutritional status
functions of adipose tissue
Blood flow in dermis and subcutaneous layers imparts a pinkish coloration to the skin
Pink:
Yellowish pigmentacquired through the diet.
carotene (yellow)
Having a thicker stratum corneum with an associated increase in the amount of the structural protein keratin; primarily found among people of _______ ________ ______
East Asian descent
a brown-black pigment produced by melanocytes found in the stratum basale; imparts a light-to-dark brown coloration to the skin, depending upon its concentration
Melanin, (brown)
differences are primarily due to differences in the amount of melanin produced and its distribution; everyone has approximately the same number of melanocytes
Human skin color
small, isolated patches of highly concentrated melanin production
Freckles:
Geographic distribution of skin color: ______ skin tones found in areas that have greatest amounts of sunlight; _______ skin tones found in areas that have least amounts of sunlight
darkest, lightest
______ absorbs ultraviolet radiation and prevents excessive amounts from reaching the actively dividing cells of_______ _________ and dermis
Melanin, stratum germinativum
Presence of a thicker also ________ _________prevents excessive _____ _______ from reaching the lower mitotic cell layers
stratum corneum
,ultraviolet radiation
melanocytes respond to increased amounts ofultraviolet radiation by producing more melanin
Tanning:
Production of _____ _ by the body is dependent upon sufficient amounts of ultraviolet radiation reaching the deeper skin layersto facilitate this chemical proces
vitamin D
In areas of low ultraviolet radiation exposure (e.g., extreme northern or southern latitudes), dark skin will result in a _________ production of vitamin D
decreased
Vitamin D is necessary for proper _______ _____; a deficiency results in rickets in children and osteomalacia in adults
bone growth
: reside in the dermisand subcutaneous layer, but originatefrom epidermal tissue; it is present on nearly all human skin surfaces, butprimarilyis short and very fine
Hair and the hair follicle
_______ houses the hair
Follicle:
zone of actively dividing cells at the base of the hair
Bulb:
a column of flattened, dead keratinized cells within the follicle
Root:
a column of flattened, dead keratinized cellsexternal to the skin’s surface
Shaft:
(composed of smooth muscle) and the production of ‘goose bumps’
Arrector pili muscle
Contraction of the _______ _________ ________ causes the hair follicle to straighten, which causes the hair to stand straight up, producing ‘goosebumps’ or ‘gooseflesh’; in response to cold environmental temperatures or fear/threatsituations
arrector pili muscle
Muscle is attached to hair follicle surface and to the dermis
arrector pilli muscle
______ _________ melanocytes located in base of hair bulb; high concentration of melanin = dark hair, moderate amount = light brown hair, little melanin = blond hair, no melanin = white hair, mixture of pigmented and unpigmented hairs = gray hair; red coloration due to pigment containing iron
Pigmentationof hair:
In adults,_____ are more likely to have more noticeable hair on back, abdomen and chest, arms, legs, and facethan _____
men, women
populations of humans differ in their degree of hair density; in general, those of European descent have the densestdistribution, East Asians and Amerindians have the least dense distribution
Geographic distribution:
modified hardened stratum corneum; divisible into nail root, nail body, and free edge
Nail plate:
underlying the nail plate; continuous with stratum basale and stratum spinosum of surrounding epidermis
Nail bed:
part of nail plate; light half-moon region at the proximal end of the nail plate, due to extreme thickness of underlying nail bed
Lunula:
Function: _______ and of ________digital dexterity
protection facilitation
: holocrine gland; secretes sebum which lubricates and waterproofs hair and stratum corneum; alveolar in shape, connected to the hair follicle
Sebaceous gland
Clogged _________ _________ (usually due tooverproduction of sebum) lead to acne
sebaceous ducts
: odoriferous merocrinesweat (aka, sudoriferous) gland, concentrated in axillary and pubic regions; responds to emotional stress; tubular in shape, connected to the hair follicle
Apocrine gland
merocrine sweat gland, found all over the body, especially forehead, back, palms, and soles; functions in evaporative cooling of the body, plus excretion of certain bodily wastes; tubular in shape, exits directly onto the surface of the skin
Eccrine gland:
Involving just the epidermis: results in greater mitotic activity in the stratum ____and stratum ______
basale and spinosum
Wound causes rupture of blood vessels within the dermis (and subcutaneous layer, if that extensive), with resultant bleeding
Involving the dermis and/or subcutaneous layer
Blood ______ and _____ proteins form a clot, which stops bleeding
platelets, fibrinogen
healing of wounds
Scab forms and seals off wound
i.May see signs of inflammation (redness, swelling, heat, pain) as damaged cells and foreign microorganisms are destroyed by immune cells
d.Fibroblasts form collagen fibers which bind wound edges together; epithelial cells migrate in from wound edges and start proliferatinge.
Scab sloughs off when healing is complete
: injury to epidermis only; skin becomes warm and reddened, surface layers of skin may be shed(i.e., ‘peeling’
First-degree (aka, superficial partial-thickness)
: destruction of epidermis and some underlying dermis as well (but not accessory organs); skin blisters and healing may involve epithelial cells from accessory organs within damaged area
Second-degree (aka, deep partial-thickness)
destroys epidermis, dermis, and accessory organs; epithelialhealing can occur only at margins of injury
Third-degree (aka, full-thickness):
damage extends from epidermis into the subcutaneous layer
Fourth-degree:
: thought to be due tolong-term exposure to ultravioletradiation; malignant; divisible into basal cell carcinoma and squamous cell carcinoma
Cutaneous carcinoma
thought to be due to relatively short, but intense exposure to ultraviolet radiation; highly malignant
Cutaneous melanoma:
________ rule for identification of cutaneous melanoma: asymmetry, irregular borders, abnormal and/or multiple colors, increasing or large diameter (larger than a pencil eraser)
ABCD’
benign growth of pigmented melanocytes
Mole (aka, nevus):
abnormal growth of skin tissue caused by viral infection
Wart (aka, verruca):
Integumentary system as a clinical indicator
- Dietary deficiencies
- Heavy metal exposure
- Allergic reactions
- Specific diseases
signs of aging
- Lossof elasticity in the dermis
- Decrease in amount of adipose tissue in subcutaneous layer
- Decreased activity of hair follicles and exocrine glands (especially, eccrine and sebaceous glands)a.Loss of pigmentation in hair
- Increase in number of moles
