MEDI 101 Lecture human tissues 1 and 2 (week 3)

tissues

• groups of tisues similar structure and function

• four types: epithelial, connective, muscle, nervous

epithelial tissues

• cover and line body surfaces

• often form sheets with one free surface, the apical surface, the basement surface

• avascular (no blood supply)

• Regenerate easily if well nourished

squamous

the shape is flattened, like fish scales

cuboidal

the tissue is cube-shaped, like dice

columnar

the tissue is shaped like columns

simple epithelia

• Functions in absorption, secretion, and filtration

• Very thin (so not suited for protection)

simple squamous epithelium

• Single layer in membranes of flat cells

• Locations—usually forms membrane

• Functions in diffusion, filtration, or secretion

• found in: air sacs of lungs, walls of capillaries, forms of serous membranes

simple cuboidal epithelium

• A single layer of cube-like cells

• Functions in secretion and absorption; ciliated types propel mucus or reproductive cells

• found in: glands in their ducs, walls of kidney tubules, surface of ovaries

simple columnar epithelium

• Single layer of tall cells

• Functions in secretion and absorption; ciliated types propel mucus or reproductive cells

• found in: lining of the digestive tract, mucous membranes

pseudostratified columnar epithelium

• All cells rest on a basement membrane

• Single layer, but some cells are shorter than others giving a false (pseudo) impression of stratification

• Functions in absorption or secretion

• found in: respiratory tract

stratified epithelia

• Consist of two or more cell layers

• Function primarily in protection

stratified squamous epithelium

• Most common stratified epithelium

• Named for cells present at the free (apical) surface, which are squamous

• Functions as a protective covering where friction is common

• found in: skin, mouth, esophagus

stratified cuboidal epithelium

two layers of cuboidal cells; functions in protection

stratified columnar epithelium

• surface cells are columnar, and cells underneath vary in size and shape; functions in protection

Stratified cuboidal and columnar

• Rare in human body

• Found mainly in ducts of large glands

transitional epithelium

• Composed of modified epithelium cells called dome shape/umbrella cells on the surface

• Shape of cells depends upon the amount of stretching

• Functions in stretching and the ability to return to normal shape

• found in: lining of urinary system organs

glandular epithelia

• One or more cells responsible for secreting a particular product

• Secretions contain protein molecules in an aqueous (water-based) fluid

• Secretion is an active process

endocrine glands

• Ductless; secretions (hormones) diffuse into blood vessels

• Produce molecules called hormones

• Examples include thyroid, adrenals, and pituitary

exocrine glands

• Secretions empty through ducts to the epithelial surface

• Include sweat and oil glands, liver, and pancreas (both internal and external)

connective tissue

• Found everywhere in the body to connect body parts

• Includes the most abundant and widely distributed tissues

• variations in blood supply

• contain extracellular matrix

bone

• osseous tissue

• composed of osteocytes sitting in lacunae, hard matrix of calcium salts, large numbers of collagen fibers

• to protect and support the body

central canal

• or haversian canal

• Opening in the center of an osteon (Haversian system)

• Runs lengthwise through bone

• Carries blood vessels and nerves

• Perforating (Volkmann’s) cana

osteon

• A unit of bone containing central canal and matrix rings

• Structural and functional unit of compact bone

cartilage

• Less hard and more flexible than bone

• Found in only a few places in the body

• Chondrocyte (cartilage cell) is the major cell type

hyaline cartilage

• Most widespread type of cartilage

• Abundant collagen fibers hidden by a glassy, rubbery matrix

• found in: trachea, ribs to breastbone, covers ends of long bones, epiphyseal plates in long bones

elastic cartilage

• Provides elasticity

• Location: supports the external ear

fibrocartilage

• Highly compressible

• Location: forms cushion-like discs between vertebrae of the spinal column

dense connective tissue

• main matrix element is collagen fiber

• Fibroblasts are cells that make fibers

• found in: tendons, ligaments, dermis

loose connective tissues

• Softer, have more cells and fewer fibers than other connective tissues (except blood)

areolar connective tissue

• Most widely distributed connective tissue

• Soft, pliable tissue like “cobwebs”

• Functions as a universal packing tissue and “glue” to hold organs in place

• Layer of _____ called lamina propria underlies all membranes

• All fiber types form a loose network

• can soak up excess fluid (causes edema)

adipose connective tissue

• An areolar tissue in which adipose (fat) cells dominate

• insulates the body, protects some organs, site of fuel storage

• found in: Subcutaneous tissue beneath the skin, kidneys, Fat “depots” include hips, breasts, and belly

reticular connective tissue

• A delicate network of interwoven fibers with reticular cells (like fibroblasts)

• Forms stroma (internal framework) of organs

• found in: lymph nodes, spleen, bone marrow

blood

• or vascular tissue

• surrounded by a fluid matrix known as blood plasma

• Soluble fibers are visible only during the clotting

• Functions as the transport vehicle for the cardiovascular system, carrying: nutrients, wastes, respiratory gases

simple squamous epithelium

which tissue is found in air sacs of lungs, walls of capillaries, serous membrane that line and cover organs in ventral cavity?

simple cuboidal epithelium

which tissue is found in glands and ducts, walls of kidney tubules, and surface of ovaries?

simple columnar epithelium

which tissue is found in lining of digestive tract, mucous membranes?

pseudostratified columnar epithelium

which tissue is found in the respiratory tract?

stratified squamous epithelium

which tissue is found on the skin, mouth, esophagus?

transitional epithelium

which tissue is found in the urinary system organs?

endocrine glands

which gland is found in the thyroid, adrenals and pituitary?

exocrine glands

which glands is found in the sweat and oil glands, liver and pancreas, salivary glands?

hyaline cartilage

which cartilage is found in the trachea, ribs to breastbone, growth plates in long bones and fetal skeleton prior to birth?

elastic cartilage

which cartilage is in the external ear?

dense connective tissue

which tissue is found in the tendons, ligaments, dermis?

reticular connective tissue

• which tissue can be found in lymph nodes, spleen and bone marrow?

skeletal muscle tissue

• Packaged by connective tissue sheets into skeletal muscles, which are attached to the skeleton and pull on bones or skin

• Voluntarily (consciously) controlled

• Produces gross body movements or facial expression

• Has striations, multinucleate, long cylindrical shape

cardiac muscle tissue

• Involuntarily controlled

• Found only in the heart

• Pumps blood through blood vessel

• has striations, one nucleus per cell, short branching cells, intercalated discs with gap junction

smooth muscle tissue

• Involuntarily controlled

• Found in walls of hollow organs such as stomach, uterus, and blood vessels

• Peristalsis, a wavelike activity, is a typical activity

• no striations, one nucleus per cell, spindle-shaped cells

neurons

• or nerve cells

• cells specialized to transmit messages (nerve impulses)

• Major regions of all neurons (cell body and processes)

cell body

• is the metabolic center of the neuron

• has nuclues with large nucleolus

nissl bodies

• the rough endoplasmic reticulum in the neuron

neurofibrils

• intermediate filaments in the neuron the maintain cell shape

dendrites

• conduct impulses toward the cell body

• neurons may have hundreds of these

axons

• conduct impulses away from the cell body

• neurons have only one of this arising from the cell body at the axon hillock

• end in axon terminals, which contain vesicles with neurotransmitters

• Axon terminals are separated from the next neuron by a synaptic gap

synaptic cleft

• gap between axon terminals and the next neuron

synapse

• functional junction between nerves where a nerve impulse is transmitted

myelin

• White, fatty material covering axons

• Protects and insulates fibers

• Speeds nerve impulse transmission

• damage to this sheath due to autoimmune disease is multiple sclerosis

schwann cells

• wrap axons in a jelly roll–like fashion (PNS) to form the myelin sheath

neurilemma

• part of the Schwann cell external to the myelin sheath

nodes of ranvier

• gaps in myelin sheath along the axon

Oligodendrocytes

• produce myelin sheaths around axons of the CNS

• Wrap around nerve fibers in the central nervous system

• lack a neurilemma

neuroglia

• or glial cells or glia

• Insulate, support and protect neurons

• they resemble neurons, Unable to conduct nerve impulses and never lose the ability to divide

• divided into 6 types

nervous tissue

• made up of two principal cell types (neurons and supporting cells)

• Function is to receive and conduct electrochemical impulses to and from body parts (irritability and conductivity)

astrocytes

• Abundant, star-shaped cells

• Brace and anchor neurons to blood capillaries

• Determine permeability and exchanges between blood capillaries and neurons

• Protect neurons from harmful substances in blood

• Control the chemical environment of the brain

microglia

• Spiderlike phagocytes

• Monitor health of nearby neurons

• Dispose of debris

ependymal cells

• Line cavities of the brain and spinal cord

• Cilia assist with circulation of cerebrospinal fluid

satellite cells

• Protect and cushion neuron cell bodies

• in the peripheral nervous system

epithelial membranes

• are simple organs

• Also called covering and lining membrane

• contain epithelial tissues layer and connective tissue layer

cutaneous membrane

• skin

• Dry membrane

• Outermost protective boundary

• construction: epidermis and dermis

mucous membrane

• or mucosae

• Moist membrane

• Line all body cavities that open to the exterior body surface

• Adapted for absorption or secretion

• construction: epithelium type depends on site, has loose connective tissue (lamina propria)

serous membrane

• or serosae

• Line open body cavities that are closed to the exterior of the body

• Occur in pairs, separated by serous fluid, with a visceral and parietal layer

• construction: simple squamous epithelium and areolar connective tissue

synovial membranes

• Loose areolar connective tissue only (no epithelial tissue)

• Line fibrous capsules surrounding joints (Line bursae Line tendon sheaths)

• Secrete a lubricating fluid to cushion organs moving against each other during muscle activity

simple cuboidal epithelium

what tissue is this?

simple columnar epithelium

what tissue is this?

pseudostratified columnar epithelium

what tissue is this?

stratified squamous epithelium

which tissue is this?

transitional epithelium

which tissue is this?

stratified cuboidal epithelium

which tissue is this?

bone

which tissue is this?

hyaline cartilage

which tissue is this?

fibrocartilage

which tissue is this?

dense connective tissue

which tissues is this?

areolar connective tissue

which tissue is this

adipose connective tissue

which tissue is this?

reticular connective tissue

which tissue is this?

blood

which tissue is this?

skeletal muscle

which muscle is this?

cardiac muscle

which muscle is this?

smooth muscle

which muscle is this?

neuron

what is this?