Chapter 5 The Human Tissues Flashcards
Tissue
Collection of cells that function together to carry out specialized activities
Tissues can be:
Solid -bone
Semi solid -adipose tissue
Liquid -blood
Histology
Science of the study of tissues
Pathologist
Specialize in studies of cells and tissues
Epithelial tissue
Covers body surfaces, lines hollow organs and forms glands
Connective tissue
Protects and supports the body and organs
Muscle tissue
Generates physical force to make the body move, maintain posture, move substances and produce heat
Nervous tissue
Detects change in conditions inside and outside the body and responds by generated nerve signals to maintain homeostasis
Cellularity
Epithelia are composed of cells closely bound together with cell junctions, cells are tightly packed with extracellular material
How are epithelial cells arranged?
In sheets, in either single or multiple layers
Apical surface
Exposed surface that faces the body surface, a body cavity, a duct receiving secretions or an internal organ
Basal surface
Attached surface attached to underlying tissue
Basement membrane
Base of an epithelium, a thin extracellular layer
Avascularity
Without blood.
The exchange of materials between epithelium and adjacent connective tissue is by diffusion
Functions of epithelial tissues
-protect deeper tissues from injury and infection
-produce and release chemical secretions
-excrete waste
-absorb chemicals and nutrients
-sense stimuli
-filter substances
Epithelial tissues are categorized based on two features:
Number of cells
Shape of cells in the uppermost layer
Simple=
One layer of cells
Stratified=
More than one layer of cells
Pseudostratified=
Looks multilayered but all cells touch the basement membrane
Simple squamous
-permits rapid diffusion or transport of substances
Located: alveoli, glomeruli, endothelium, serosa
Simple cuboidal
-absorption and secretion, mucus production and movement
Located: liver, thyroid, mammary and salivary glands, bronchioles, kidney
Simple columnar
-absorption and secretion
-secretion of mucus
Located: uterus, GI tract, kidney, uterine tubes
Stratified kerantized squamous
Resists absorption
Located: epidermis, palms and soles
Non kerantized stratified squamous
Resists absorption
Located: tongue, oracl mucosa, vagina, esophagus
Stratified cuboidal
Secretes sweat, produces sperm, produces hormones
Located: sweat gland ducts, ovarian follicles, seminiferous tubules
Transitional epithelium
Surface cells change shape from round to flat when stretched
-allows for filling or urinary tract
Located: ureter and bladder
Types of cellular junctions
-tight junction
-desmosome
-gab junction
Cell junction
When a cell membrane contacts another cells membrane. They get held together by cell junctions
Tight junctions
Two cells membranes are fused together with strips of proteins
Gap junction
Join two cells together but leave a little gab that joins the cytoplasms together
Desmosomes
Connections made of trans membrane proteins that are connected to the cells cytoskeleton
Basal lamina
The layer closest to the basal surface of the epithelial cells, it’s made of collagen fibers
Reticular lamina
Layer deep to the basal lamina, contains structural proteins and reticular fibers
Basement membrane functions
-attach epithelial tissue to connective tissue
-guide cells during growth and repair
-acts as a barrier
-acts as a filter
Gland
Consist of a group of cells that secrete substances into ducts onto surface or into the blood
Endocrine glands
Secretions are released into the interstitial fluid and diffuse directly into bloodstream
-hormones
Exocrine glands
Secretions are released into ducts that empty onto the surface of a lining epithelium
Connective tissues
Most widely and abundant distributed tissue in the body
Three basic elements of connective tissue
Cells, fibers, ground substance
Blast type cells
Cells that retain ability to divide and produce matrix
Ctye type cells
Cells that have reduced ability to produce matrix and divide
They maintain the matrix
Collagen fibers
Very tight and resistant to stretching, found in:
Bone, cartilage, ligaments, tendons
Reticular fibers
Provide support in walls of Blood vessels and form a strong network around adipose cells, nerve fibers,skeletal and smooth muscle fibers
Elastic fibers
Provide strength and stretching capacity, found in: skin, blood vessels, lungs
Ground substance
Contains water and large molecules, supports exchange of materials between the blood and cells
Matrix tends to
Prevent tissue cells from touching one another
Functions of connective tissues
-connect organs
-support
-physical protection
-movement
-storage
-transport
-heat production
-immune protection
Regeneration
Replacement of dead or damaged cells by the same type of cell as before
Fibrosis
Replacement of damaged cells with scar tissue
Areolar tissue
Loosely organized fibers
Pathway for nerves and blood vessels
Reticular fibers
Mesh of reticular fibers and fibroblasts
Forms support
Found in: lymph nodes, spleen, thymus and bone marrow
Adipose tissue
Empty looking cells with thin margins
Energy storage, insulation and cushioning
Dense regular connective tissue
Densely packed collagen fibers and elastic tissues in waves
Holds bones together
Dense irregular connective tissue
Densely packed randomly arranged collagen fibers
Withstands stress
Located: deeper layer of skin, capsules around organs
Hyaline cartilage
Clear glassy appearance
Eases joint movement, holds airway open, moves vocal cords
Located: in cartilage, trachea, larynx, fetal skeleton
Elastic cartilage
Provides flexible elastic support
Located: external ear and epiglottis
Fibrocartilage
Contains large bundles of collagen fibers
Absorbed shock
Located: pubic symphysis, intervertebral discs
Compact bone
Blood vessels and nerves travel through central canal
Blood
Fluid connective tissue
Transports cells and dissolved matter from place to place
Nervous tissue
Specialized for communication by electrical and chemical signals
Respond to stimuli
Cardiac muscle tissue
Limited to heart wall
Short with one central nucleus
Smooth muscle tissue
Making up parts of walls or hollow organs
Involuntary function
Skeletal muscle tissue
Made of muscle fibers
Attach to bone
Voluntary
