Module 4: Tissues Flashcards
4 classifications of tissues
Epithelial
Connective
Nervous
Muscle
Epithelial Tissue
AKA epithelium
Covers external surface of the body and lines internal cavities and forms glands
no nerve supply or blood supply
Tight junctions/Desmosomes
eip’s fit snugly together
very small amount of extracellular material between the narrow spaces of epi’s
Apical
Free or open surface of the epi
Most have microvilli on their surfaces (for better absorption or secretion)
Basal Lamina
non cellular, thin supporting sheet at the bottom of the epic
provides selective barrier
Shapes of Epi’s
Squamous (thin, flat, nucleus shaped like disk)
Cuboidal (cube like, nucleus shaped like sphere)
Columnar (Tall and narrow, nucleus is long and narrow)
Layers of Eips
Simple (one layer)
Stratified (2 or more layers)
Simple squamous
lungs
for diffusion of oxygen and carbon dioxide
simple cuboidal
kidney tubules
for absorption and secretion
simple columnar
digestive tract
for absorption of nutrient and secretion of mucus
Pseudostratified Columnar
trachea
For secretion of mucus
Stratified squamous
epidermis of skin
for protection
Stratified cuboidal
swear and mammary glands
for protection
stratified columnar
pharynx and male urethra
protection and secretion
Transitional Epis
Lining of urinary bladder
stretches in response to tension when urine fills the bladder
Functions of Epithelial tissues
Protection
Sensory functions (receptors in epis in skin, nose, eyes, ears)
Secretion (glandular epis)
Absorption
Excretion (lining in kidneys filtrates urine)
Exocrine Glands
Secret substances onto free surface via ducts
substances include digestive enzymes, mucus, saliva, perspiration, breast milk
Endocrine Glands
Ductless, secret their substances directly onto surround tissues and blood
Substances include: hormones from pituitary, thyroid and adrenal glands
Connective tissue types (4)
cartilage, ligaments, tendons, bone, blood
has embryonic origin (mesenchyme)
has blood supply (vascular) except cartilage
Has an extracellular matrix
Parts of connective tissue
Specialized cells (fibroblast, macrophage, plasma, mast cells) Extracellular protein fibres (collagen, elastic) Ground substance (liquid, gel-like or solid form)
Collagen fibers
flexible and strong
found in bone and cartilage
Elastic fibers
Made from elastin
not as strong as collagen (but can return to original shape)
found in skin, walls of blood vessels, lung tissue
Reticular fibers
Made from collagen (but arranged differently)
thin but organized
found in soft organs such as glands and lymph nodes
Classification fo connective tissue (5)
loose connective, dense connective, cartilage, bone, blood
Loose connective tissue
loosely packed fibres
Subcategories: Areolar
Adipose
Reticular
Areolar
Binds organs together giving strength, elasticity and support
most dispersed, found underneath tips, in cavities, between muscles
Adipose
Provides protection, insulation, support and place to store energy
fat tissue found under the skin, around kidneys, within abdomen and kidneys
Reticular
Defends the body by filtering out microorganisms and other substances
Network of branching fibres found in spleen, lymph noes, bone marrow
Dense connective tissue
Densely packed fibers
Subcategories: dense regular
Dense irregular
elastic
Dense regular
provides tensile strength and flexibility for anchoring muscles to bones and bones to bones
Found in tendons and ligaments
Dense irregular
Withstands stresses applied from any direction
Forms the dermis (inner skin layer); and outer layer of kidneys and spleen
Elastic (Dense connective tissue)
Provides strength with stretching
Found in the wall of arteries
Cartilage tissue
Both tough and flexible (due to high water content) Lacks nerves and is avascular Specialized cells called chondrocytes Subcategories: hyaline fibrocartilage elastic
Hyaline
Provides support with flexibility
absorbs shock in joints
“gristle” is most abundant type of cartilage
found in ends of long bones, larynx, nose, between sternum and ribs
Fibrocartilage
Provides protection and cushions body parts
found in intervertebral discs, knees, between pubic bones
Elastic (cartilage)
provides support and a framework
found in the external ear and epiglottis
Osseous
bone tissue
consists of bone cells that are embedded in a hard matrix of calcium and salts
Vascular connective tissue
blood tissue
consists of blood cells in a fluid matrix (plasma)
Membranes
Thin sheets of tissue
Serous membranes line the ventral body cavities (not open to the exterior of the body)
Serous fluid reduces friction between cavities
Nervous tissue
Conducts electrical impulses
98% of nervous tissue in is central nervous system (brain and spinal cord)
Composed of neurones and neuroglia (glial cells)
Muscle tissue
AKA muscle fibers contain protein (actin and myosin)
Muscles contract when these proteins interact
3 types: Skeletal, smooth, cardiac
Skeletal muscle
Striated voluntary muscle
attaches to bones of the skeleton
moves body parts
fastest contracting
Smooth muscle
non striated involuntary muscle
found in internal organs and blood vessels
contraction are slower than skeletal but muscles remain contracted for a longer period of time
Cardiac Muscle
striated involunatry muscle
found only in the heart
resembles skeletal muscle but behaves like smooth muscle
Tissue repair
Regeneration and fibrosis
Regeneration
replacement of cells that are identical to the originals
occurs in tissues whose cells undergo replication (mitosis)
ex. worn out skin cells
Fibrosis
Replacement by the formation of fibrous connective tissue (scar tissue)
very strong but lacks flexibility and elasticity
Steps of tissue repair
1) inflammation -stimulates immune system
2) organization - restores blood supply and replaces damaged cells
3) regeneration and fibrosis - the repaired tissue remoulds itself
Tissues and aging
Loss in height due to fallen arches, worn out disks
Decrease in lung capacity, muscle strength, kidney function
Brittle bones that break
Easy to bruise
Joint pain
Deterioration of mental functions
