AnP Chapter 5 (LO4) Flashcards
tissues
Group of similar cells that perform a common function
entire body including blood and bone is made of tissue
4 distinct groups of tissue
epithelial
connective
nervous
muscular
functions of tissue
tissue holds together the body
provides the body with it’s shape
gives it the ability to move
TISSUE DEVELOPMENT
- once egg/sperm unite to form a single cell it begins to divide rapidly (all identical)
- cells organize into 3 layers
- ectoderm (outer layer)
- mesoderm (middle layer)
- endoderm (inner layer) - Cells continue to divide; each layer becoming distinct from other layer
- Differentiation: each layer gives rise to different type of tissue
Ectoderm
outer layer
gives rise to epidermis and nervous system
- epidermis
- nervous tissue
Endoderm
inner layer
produces mucous membrane of respiratory tract, thyroid gland, secretory parts of pancreas
- Lung tissue
- thyroid tissue
- pancreatic tisssue
mesoderm
middle layer
gives rise to connective and muscle tissue
- cardiac muscle
- skeletal muscle
- bone
- blood
Stem cells
differentiate into many different types of cells such as liver cells, skin cells or blood cells
200 types
EPITHELIAL TISSUE
surface tissue
Continuous sheet of tightly packed cells
Covers body surface, lines body cavities/organs and forms certain glands
It’s top surface usually exposed to the environment
It’s bottom surface adheres to underlying connective tissue (basement membrane)
Too thin to contain blood vessels; depends on the connective tissue underneath to supply it oxygen and nutrients
key functions of epithelial tissue
Protection
Absorption
Filtration
Secretion
Join with tight junctions and make it difficult for some substances to pass between cells
CLASSIFICATION OF EPITHELIAL TISSUE
Classified by shape of the cells and # of layers
cell shapes
squamous
cuboidal
columnar
cell layers
simple epithelia
-Every cell touches the basement membrane
Stratified epithelia
-Some stack on top of others and upper layers of cells don’t touch basement membranes
Glandular epithelium
- exocrine glands
- endocrine glands
- goblet cells
Gland
a collection of epithelial cells that specializes in secretion of a particular substance
Exocrine glands
secrete their products (sweat, tears, gastric juices) into ducts
The ducts empty onto a body surface inside a body cavity
Endocrine glands
ductless glands; secrete products (hormones) into the blood
ex) adrenal glands secrete epinephrine and norepinephrine into blood includes: pituitary, thyroid, ovaries
Goblet cells
modified cells containing secretory vesicles that produce large quantities of mucus
definition, function and locations: Simple squamous epithelium
- consists of a single layer of flat, scale like cells
- allows for ready diffusion or filtration because of thinness
- Alveoli
- lining of blood and lymphatic vessels
definition, function and locations: Simple cuboidal epithelium
- consists of a single layer of cube like cells
- secretes and absorbs
- ducts and tubules of many organs including kidneys
definition, function and locations: Simple columnar cells
-consists of a single layer of columnar cell
- participates in absorption
- secretes mucus by goblet cells
-lines intestines
definition, function and locations: Pseudostratified columnar
Pseudostratified columnar
- consists of a single layer of irregularly shaped columnar cells
- cells of different heights with nuclei at different levels makes it appear stratified
- protection
- secretes mucous
-lines trachea large bronchi and nasal mucosa
stratified definition
several layers
definition, function and locations: stratified squamous epithelium
- contains multiple cell layers (making it stronger than simple epithelia)
- most wide spread epithelium in the body
- resist abrasions and penetration by pathogens
- some contain keratin (such as the epidermis) some do not (such as the mucous membrane)
- epidermis of skin
- esophagus
- vagina
definition, function and locations: Transitional epithelium
- consists of multiple layers
- when stretched, cell layers decrease and cell shape changes from cuboidal to squamous
- stretches to allow filling of urinary tract
- urinary tract
connective tissue
Most widespread and most varied
Connects together and binds, supports and protects organs
TYPES OF CONNECTIVE TISSUE
Dense fibrous (ligaments) Adipose (fat) Bone Blood Areolar (under epithelial) Reticular (frame work of spleen) Cartilage (vertebral discs)
COMPONENTS OF CONNETIVE TISSUE
Extracellular matrix
Framework into which the cells of tissues are embedded
Consists of varying kinds/amounts of protein fibers and fluid (variation in composition that gives tissues it’s characteristics)
May be: gel-like, flexible, tough, fragile, brittle or liquid
Extracellular matrix
allows connective tissues to be diverse
3 TYPES OF FIBERS FOUND IN CONNECTIVE TISSUE
Collagenous fibers
Reticular fibers
elastic fibers
how are connective tissues classified
according to their structural characteristics
classifications of connective tissue
loose or dense
- areolar tissue
- adipose tissue
- reticular tissue
Cartilage
Bone
Blood
FIBROUS CONNECTIVE TISSUE
Fibers may be loosely arranged or tightly packed