Chapter 5 Flashcards
tissues
a group of similar cells and extracellular matrix that have a common goal
4 types of tissue
muscle, nervous, epithelial, connective
stem cells
cells without a name or specific job. they maintain cell populations in tissues that have short lives and divide frequently
differentiation
specification of stem cells
epithelial tissue
covers body surfaces, lines body cavities, and forms most glands
epithelium
composed of one or more layers of closely packed cells with little extracellular matrix and no blood vessels.
10 Characteristics of epithelial tissue
cellularity, polarity, attachment to basement membrane, avascularity, extensive innervation, high regeneration capacity, physical protection, selective permeability, secretions, and sensations.
cellularity
epithelium is composed of tightly packed cells
polarity
epithelium has an apical surface that is exposed to environment and a basal surface that anchors it to connective tissue
attachment to basement membrane
basement membrane is complex structure produced by epithelium and connective tissue.(lamina lucida, lamina densa, reticular lamina). contains collagen fibers and specific proteins and carbs. forms a selective barrier between epithelium and connective tissue
Avascularity
no blood vessels in apical surface
extensive innervation
skin detects changes in the environment in that region
high regeneration capacity
apical cell are frequently lost and replaced through mitosis of the deepest epithelial stem cells adjacent to the basement membrane
physical protection
skin protects from dehydration, abrasion, and destruction
selective permeability
skin is impermeable to some substances but promotes the passage of others
secretions
some skin secrete and may form glands
sensations
skin contains nerve endings
tight junctions
cell is completely attached to its neighbor through a fused plasma membrane. This prevents substances passing between cell in places like the small intestine and bladder
desmosomes
holds cells together at a single point; found in cells exposed to stress
gap junctions
forms tiny, fluid-filled tunnels that allow substances to travel directly to other cells. found between cells in cardiac muscle to allow flow of ions.
glands
cells or organs composed of epithelial tissue that secretes substances for use elsewhere or elimination.
endocrine glands
have no ducts; secrete hormones directly into body fluids (like interstitial fluid and blood). hormones act like chem. messengers that influence cell activity everywhere.
exocrine glands
formed from folded epithelium within connective tissue and is connected to epithelial surface by a duct (sweat mammary, salivary)
merocrine gland
exocrine gland that uses vesicles and exocytosis. happens in lacrimal, salivary, sweat, pancreas, and stomach
apocrine glands
exocrine gland pinching off cytoplasm and exocytosis. happens in mammary and some sweat glands.
holocrine glands
exocrine gland that uses accumulation and then cell disintegration (sebaceous glands)
Functions of connective tissue
physical protection, support and structural framework, binding of structures, storage, transport, and immune protection.
physical protection in connective tissue
bones of skull and thoracic cage protect organs and adipose tissue protects kidney and eyes
support and structural framework of connective tissue
bones are framework; cartilage keeps trachea and bronchi open, supportive tissues are around kidney and spleen
binding of structures in connective tissue
ligament bind bone to bone
tendons bind muscle to bone
dense irregular tissue anchors skin to muscle and bone
storage
adipose tissue is major energy reserve and bones reserve calcium and phosphorus
transport in connective tissue
blood carries nutrients, gases, and wastes
immune protection in connective tissue
leukocytes protect body against disease. extracellular matrix restricts movement of infections organisms
body membranes
formed from epithelial tissue bound to underlying connective tissue. lines body cavities, covers viscera and body’s external surfaces
4 types of body membranes
mucous, serous, cutaneous, and synovial
mucous membrane
lines compartments that open to external environments. Absorb, protect, and secrete. Formed from epithelium and underlying connective tissue covered in mucus
serous membrane
lines body cavities not opening to outside. Membrane is composed of simple squamous cells termed mesothelium. Produces serous fluid that is derived from blood plasma. functions to reduce friction between surfaces
cutaneous membrane
skin; covers external surface of the body to protect internal organs and prevent water loss. it is composed of keratinized stratified squamous cells and underlying connective tissue
synovial membrane
lines some joints; composed of areolar connective tissue covered by squamous epithelial cells with no basement membrane. Secretes synovial fluid that reduces friction among moving bones and brings nutrients to cartilage
metaplasia
when epithelial cells change into another form as it adapts. (ex: smokers trachea- pseudostratified ciliated columnar to nonkeratinized stratified squamous
hypertrophy
increase in size of existing cells of a tissue
hyperplasia
increase in number of cells of a tissue
neoplasia
out of control tissue growth forming a tumor
atrophy
shrinkage of tissue by decrease in cell number or size. results from inactivity or aging.
necrosis
tissue death. causes an inflammatory response to the damage
gangrene
necrosis of soft tissue due to lack of arterial blood supply. most common in diabetics and in the limbs. may require tissue removal and antibiotics
intestinal gangrene
follows obstruction of blood supply to intestines
dry gangrene
involved area is shriveled; usually due to extreme cold
wet gangrene
caused by bacterial infection of tissue with loss of blood supply. the ruptured cells release fluid
gas gangrene
bacteria invades necrotic tissue and produces gas bubbles
changes to aging tissue
support, maintenance, and replacement of cells is less efficient. structure and chem. composition may change (get thinner and less resilient), less collagen, brittle bones, muscle and nervous atrophy
components of integumentary system
skin, nails, hair, sweat and sebaceous glands
Integument
skin covering to body; also known as cutaneous membrane. Serves as a barrier and visual indicator of health.
study of skin
dermatology
area of integument
1.5-2.0 m2
thickness of integument
1.5-4.0mm
what tissue types is the integument composed of
all 4
3 layers of integument
epidermis, dermis, subcutaneous layer
thick skin
on palms and feet. has all 5 layers of epidermal strata and has sweat glands. no hair or sebaceous glands. 0.4-0.6 mm thick
thin skin
covers most of body, lacks stratum lucidum. has sweat and sebaceous glands and hair. 0.075-0.15 mm thick
Functions of integument
protection, prevention of water loss, metabolic regulation, secretion and absorption, temperature regulation, and immune function
protection
protects against trauma, chemicals, toxins, microbes, temp, and solar radiation
prevention of water loss
water cannot exit unless secreted by sweat glands. Integument is water resistant, not waterproof.
transpiration
release of water vapor from sweat glands when not sweating. (some interstitial fluid penetrates through epidermis to air)
Metabolic regulation
Vitamin D3 (cholecalciferol) is synthesized from a steroid precursor by keratinocytes upon uv exposure. D3 is released into blood and transported to liver where it is converted to an intermediate molecule. Transported to kidney and converted to calcitriol: the active form of vitamin d that is a hormone to increase absorption of calcium and phosphate to increase bone density and regulate those levels in the blood
Secretion
Waste products are secreted onto skin during sweating (urea, salt, water)- this plays a role in electrolyte homeostasis. Sebum lubricates skin surface
Absorption
Can absorb certain chemicals and drugs that are oil soluble. Skin is selectively permeable.
Transdermal administration
oil soluble drugs delivered by an adhesive patch- absorbed in blood vessels of the dermis
Temperature regulation
body temp influenced by capillaries and sweat glands. dilation and sweating=hot; constriction=cold
Immune Function
dendritic cells within stratum spinosum in epidermis initiate immune response against pathogens and attack cancer cells. also found in dermis
hemoglobin
oxygen binding compound present in red blood cells. Bright red when exposed to oxygen, gives blood vessels in dermis a reddish tint seen more easily in fair skin. More visible if blood vessels dilate. Helps determine skin color
Melanin
pigment produced and stored in melanocytes- occurs in black, brown, tan, and yellow-brown shades. transferred to keratinocytes in stratum basale. Amount in skin due to heredity and light exposure All people have the same number of melanocytes.
Carotene
yellow-orange pigment acquired from similarly colored vegetables. Accumulates in fat and keratinocytes of stratum corneum. Converted to vitamin a within body. Plays an important role in vision, reducing free radicals and immune function
Hemangioma
skin discoloration due to benign blood vessel tumor.
Capillary hemangiomas
appear in skin as bright red to deep purple nodules; usually present at birth and disappear in childhood. Known as strawberry-colored birthmarks.
Cavernous hemangiomas
involves larger dermal blood vessels and may last a lifetime. known as port-wine stains
Nevus
commonly called a mole. Overgrowth of melanin forming cells- rarely may become malignant and should be monitored
Freckles
yellowish or brown spots. Represent localized areas of increased melanocyte activity. Degree of pigmentation based on heredity and sun exposure.
