Review Sheet -- Test 1, number 2: Tissues
Biology 2212 Dr. Adams
ALSO for
first LAB PRACTICAL
Chapter 4 -- Tissues
Tissue: Group of similar cells functioning together as a unit.
Four major classes: NOT ALL LOCATIONS/FUNCTIONS LISTED
I. Epithelial
Characteristics: very cellular, avascular, cells held together with tight junctions,
free
surface, highly regenerative, basal lamina (part of basement membrane)
A. Simple
1. Simple Squamous: Location
-- lining of circ. system, alveoli, part of serous membs.
Functions
-- rapid exchange, filtration,
reduction of friction
2. Simple
Cuboidal: Location -- glands, kidney tubules; Functions -- secretion
(virtually
all glandular epithelium is simp. cub.; see * below), exchange (in
kidney)
3. Simple Columnar: Location
-- digestive system (what parts?), oviducts, resp.
tract
(part);
Function -- absorption, secretion. In some places, simple columnar epith. has
microvilli
(small intestine) or cilia (uterine tubes); goblet cells often associated.
4. Pseudostratified (ciliated) columnar
-- respiratory system (what parts?);
Functions -- secretion (mucus), movement of unwanted garbage
Goblet cells often associated
B. Stratified
1. Stratified Squamous: Location
-- skin, digestive system (what parts?),
vagina
Function
-- resist abrasion (protection)
(2. Stratified cuboidal: Uncommon, in some
gland ducts; rarely > 2 cell layers)
(3. Stratified columnar: Uncommon, in larger excretory ducts and epithelial
junctions.)
4. Transitional: Location
-- Pelvis of kidney, ureters; urinary bladder
Function
-- distension.
*C. Glandular -- MAINLY
Simple cuboidal, NOT a different type from above
cells secretory, with lots of Golgi, ER (and mitochondria)
(1. Endocrine)
2. Exocrine
-- open into cavities
(mucus membranes) or onto surface of body
a. goblet cells (unicellular)
b. multicellular: secretory units (tubular, alveolar) with ducts (simple,
compound)
classified by function:
merocrine, holocrine
II. Connective -- Characteristics: common embryonic origin (mesenchyme); cells and
matrix (extracellular material [ground substance, fibers] secreted by the cells)
Fiber types: collagen, reticular, elastic
A. Connective Tissue Proper
-- cell types: fibroblasts and -cytes, others in some
(macrophages, mast cells); usually vascular; connects tissues
1. Loose
a. Areolar
-- most widely distributed; all three fiber types, mast cells,
macrophages, occasional adipose cells; just underneath epithelium in
all three types of epithelial membranes (see below*)
b. Adipose
-- very cellular
(adipocytes)
c. Reticular
-- reticular fibers; mainly in lymph nodes, bone marrow, spleen,
liver, lungs
2. Dense
a. Regular -- collagenous; tendons and ligaments (with slightly more
elastin)
b.
Elastic -- lots of elastin fibers (duh!); vocal cords, stroma of lungs
c. Irregular -- collagenous; dermis, many other internal coverings
B. Cartilage -- cell types: chondroblasts
and -cytes; avascular and no nerves;
used for support
1. Hyaline -- collagen (regular); most widely distributed; absorbs shock
2. Fibrocartilage
-- strongest type; intervertebral disks,
some menisci
3. Elastic
-- more elastin; outer ear and ear canal,
epiglottis
C. Bone -- cell types: osteocytes and
-blasts/-clasts; lots of collagen and inorganic
calcium salts; vascular, with bone marrow (yellow/red)
D. Blood -- cell types: hematocytes (white and red); matrix: plasma (see below)
Membranes -- coverings and linings: simple organs; overlying epithelium and underlying
connective tissue
A. cutaneous
-- skin; Ep. always stratified squamous (the epidermis; underlying CT
lis a little areolar rapidly "densifying" into large layer of dense irregular
(dermis)
under the dermis is the adipose hypodermis
B. mucous -- lines cavities open to outside; epithelium varies, but CT always areolar;
(this CT of mucous membranes called lamina propria)
C. serous -- lines internal cavities
(doubled membranes: one layer lines organ
[visceral]
and other layer lines cavity [parietal]; Ep -- simple squamous,
underlying CT -- areolar
III. Muscle -- well vascularized, for movement
(actin/myosin microfilaments)
A. Skeletal -- cells striated, multinucleate, voluntary
B. Cardiac -- cells branched and interconnected (intercalated discs), uninucleate,
striated, involuntary
C. Smooth -- cells not striated, uninucleate; in walls of involuntary (hollow)
organs
IV. Nervous -- Cell types:
A. Neurons (conducting cells; 10 % of nervous tissue)
B. Glial (supporting cells; 90 % of nervous tissue)
Nerve -- many nerve cells discretely packaged by connective tissue
Tissue Repair: Either by regeneration or fibrosis (scarring) (READ TEXT)