Tissues
Terms
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- Define Tissue
- Groups of cells that are similar and perform a related function
- Define gland
- Tissue that secretes a biological product.
- Types of Tissues
-
Epithelial
Muscle
Nervous
Connective - Define Epithelial Tissue
- Sheet of cells that cover body surfaces or cavities
-
What does Epithelial Tissue Work as?
Functions? -
Interface Tissue
Apsorbtion, secretion, excretion, filtration, protection - Special Characteristics of Epithelial Tissues
- Cellularity, Polarity, Rapid Division, Innervated, Avascular, Specialized contacts, supported by connective tissue
- What are 2 surfaces of Epithelial Tissue?
-
Apical - surface (part you can see)
Basal - bottom (part you can't see)
- Acts as selective filter
- Basement membrane - Basement Membrane
- Anchors cell
- Epithelial Nomenclature
-
2 Prefixes - Stand for layers
Simple - 1 layer
Stratified - 2 or more
3 suffixes - Stand for shape
Squamous - flat
Cuboital - cubed
Columnar - columned -
Simple Squamous Tissue
Description
Function
Location -
D - single layer flattened cells, close
fitting
- sparse
- relatively permeable
F - filtration
L - areas of rapid diffusion (kidneys,
lungs) - Special Apical Structures
-
Microvilli
- tiny hairs
- aid in apsorbtion
Cilia
- tiny hairs
- move things into and out of cell -
Specialized Simple Squamous
Nickname
Description
Function
Location -
N - Endothelium
D - Top layer smooth & non thrombogenic
F - Denuding of layer exposes collagen
& thrombogenic receptors
L - Lines lymph, blood vessels, heart, &
cornea -
Simple Cuboital Endothelium
Description
Function
Location -
D - single layer of cubed shaped cells
- large spherical nucleus
F - Secretion & Absorption
L - Excretoil glands
kidney tubules
ducts
secretory portions of small glands -
Simple Columnar
Description
Function
Location -
D - Tall column shaped cells
- Round nucleus
- 2 distinct features
- contain goblet cells that secrete mucus which lubricates & protects
- dense apical microvilli
F - greater absorption & mucus secretion
L - nonciliated (dig tract)
- ciliated (bronchi, uterine tubes) -
Pseudostratified Columnar
Description
Location
Function -
D - sinlge layer of cells
F - secretion of mucus
L - sperm / trachea -
Stratified Epethelial Tissue
Description
Primary Role -
2 or more layers of cells
Basal cells - regenerate from below &
push their way to the surface
Increased durability
Primary Role / Function: Protection -
Stratified Squamous
Description
Function
Location
Other -
D - multiple layers
- stratified tissue on top
- cuboital tissue on bottom
- thick membrane
F - protects skin from abrasion
L - outer layer of skin
Receives nutrients from connective tissues -
Stratified Cuboital
Description
Location -
rare in body
two cell layers thick
mammary glands/ sweat glands -
Transitional Epithelial Tissue
Description
Location
Function -
several layers
basal - cuboital
apical - domed
resembles stratified squamous & cuboital
stretches readily / permits distention
lines urinary bladder, ureters -
Glandular Epithelium
D
Secretion components
Modes of Secrtion -
D - Classified as endocrine / exocrine
- secretion is usually aqueous
(proteins, lipids, steriods)
- Contains ducts
- can be multi or unicellular
MOS - Merocrine
- Hellocrine -
Endocrine Glands
Release?
How? -
relelase hormones
through exocytosis directly into extracellular space which then enters the blood or lympth so that it is transported to target organs -
Hormones
3 Types & Examples -
Peptides : Insulin
Steroids - Estrogen
GLycoproteins - HcG -
Connective Tissue
Description -
D - most abundant & widely distributed tissue type
- amount in particular region varies -
Connective Tissue
Common Characteristics -
-Common Origin - orig. from embryonic mesenchyme (dev. tissue)
-During dev. 3 primary layers dev. (ie. mesoderm mesenchyme)
-Composed of star shaped mesenchyme cell
-Varying degrees of vascularity
-Cartilage (only avasc. conn tissue)
-Adipose (richly vascular)
-Contains extracellular matrix (surrounds & bathes cell)