4a worksheet

Chapter 4a outline, Tissues, epithelial (p88-98)

of trillions of cells there are only about ________ different types of cells
Tissues ­­–
Histology – the study of
4 basic types of tissues
1.
2.
3.
4.

Epithelial tissues –
Epithilia –
Glands –
Characteristics of epithelia
1. cells
2. a free
3. attach to
4. absence of

5. ___________________________________continually replaced
Skin, line internal passageways (digestive, reproductive and urinary
Also line internal cavaties (chest, brain, eye, inner ear)
Line the blood vessels and the heart

4 essential functions of Epithelia
1. provide ___________________________(from _________________ ________________________________________________________).
2. control ___________________ (some are impermeable, others are more permeable)
3. provide ____________________ (touch, heat)
4. produce _______________________________ (from glands)
exocrine –
enzymes in the digestive tract, perspiration in skin, milk from mammary glands
endocrine –
hormones – __________________________________ that regulate _______________
_________________________________________________________________.

Intercellular connections
Epithelial cells held together by
____________________________________________________ (CAMs) and
____________________ cement (made of a protein—polysaccharide mixture)
Cell junctions –
1. tight junctions –
2. gap junctions – ________________________________________________________________________ ________________________(in cardiac and smooth muscle where coordinated contraction is important).
3. desmosomes – durable __________________________________________________________________ (abundant in superficial layers of the skin)

The epithelial surface
Apical surface often lined with _________________________ (for absorbtion and secretion to take place)
This increases the surface area up to ________x (more surface area à more transport proteins)
Ciliated epithelium have as much as _______ ______________ that move material across the surface
(in the respiratory tract, moves mucus-trapped air away from the lungs)

The Basement Membrane – connects to the rest of the body
A network of _________ ____________ that lay between the epithelium and underlying connective tissues
A barrier that restricts ____________________________________________________________________

Epithelial renewal and repair – maintained through _________________________________________________ ____________________________________________________________________ near the basement membrane.

Classifying epithelia (see table 4.1 and fig. 4-4, 4-5, page 93-95)
By number of layers
simple = _____________________________________ (fragile)
stratified = ___________________________________ (more protection)
Shape of cells
Squamous – _______________________ ____________________________ (like a fried egg)
Cuboidal – ________________________________________________________
Columnar – __________________________________________________________

Glandular Epithelia
Exocrine secretions produced by ____________ __________, discharged through ______________ or tubes
Endocrine secretion (hormones) produced by __________________ and released into ______________________.

Exocrine glands can be classified by mode of secretion (see figure 4-6, table 4.2, p 97)
Merocrine secretion – released by ___________________
Apocrine secretion – involves the loss of both _________________ and ____________________________.
Holocrine secretion – entire ____________________________________________ bursts to release secretion