chapter 5 histology

8/11/2019 Chapter 5 Histology

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CHAPTER 5 HISTOLOGY

I. IntroductionA. histology defined:

B. tissue types table 5.1

C. cells and a matrix

1. matrix composition

D. stains and sections

II. Epithelial tissue

A. functions

1. protection – skin, mucous membranes

2. absorption – digestive, excretory

3. filtration – excretory

4. excretion, secretion – skin, excretory

5. glands – exocrine and endocrine

B. characteristics1. closely-packed cells bound by tight junctions

and desmosomes

2. apical surface exposed to surface or organ

interior and basal surface attached to basement

membrane

3. some specialized w/ microvilli or cilia; goblet

cells esp. in resp., dig. sys.4. avascular; innervated

5. high rate of regeneration

C. classification – two names

1. simple (absorption, filtration) or stratified

(high friction areas)

2. squamous, cuboidal, columnar



D. simple epithelia

1. simple squamous

a. kidney glomeruli, alveoli,

b. endothelium of lymph and blood vessels

c. mesothelium of serous membranes

2. simple cuboidal

a. kidney tubules, ducts of glands

3. simple columnar

a. dig. tract from stomach to rectum,oviducts

4. pseudostratified

a. much of resp. tract

E. stratified epithelia – regenerate from below

1. stratified squamous

a. areas subject to abrasion

b. skin (keratinized)c. vagina, mouth, esophagus, anus

(nonkeratinized)

2. stratified cuboidal – rare; in lrg. glands

3. stratified columnar – rare; male urethra, in

transition areas

F. transitional epithelium

1. stratified, cells change shape, number of layers

as organs stretch2. urinary organs – ureters, bladder, urethra

III. Connective tissue

A. ubiquitous and abundant

B. functions

1. binding and support



2. protection

3. movement

4. storage

5. transport

C. composed of cells separated by extracellular matrix

D. matrix composed of

1. ground substance

a. glycosaminoglycans (GAG)

1) polymer of amino sugars

2) absorbs water3) chondroitin sulfate, heparin,

hyaluronic acid

b. proteoglycans – giant molecules – form

gel, hold tissues together

c. adhesive glycoproteins

2. fibers (in most)a. collagen – strongest, thick

b. elastic – stretchy

c. reticular – fine, continuous w/ collagen

fibers; branching network

E. cell types

1. blast cells – fibroblasts, chondroblasts, osteo-

blasts; hematopoietic stem cellsa. secrete matrix

b. mature to –cytes

2. mast cells

3. adipocytes

4. white blood cells and macrophages



F. fibrous connective tissue– fibroblasts; 2 classes

1. loose connective tissue – table 5.4

a. areolar – all 3 fibers, all cell types

b. reticular – fibroblasts, reticular fibers only

2. dense connective tissue –

a. dense regular – parallel collagen

1) tendons, ligaments, fascia

2) artery wallsb. dense irregular – random collagen

1) dermis, joint capsules

G. adipose tissue

1. adipocytes, scanty matrix

2. white fat

3. brown fat

H. cartilage

1. avascular, not innervated

2. matrix: lots of chondroitin sulfate, H2O and

hyaluronic acid; fibers as to type

3. chondroblastschondrocytes in lacunae

4. 3 types:

a. hyaline – most ab., support + pliability1) fetal skeleton

2) costal cartilages, tip of nose, trachea

b. elastic – like hyaline but more elastic

fibers

c. fibrocartilage – transition b/t hyaline

and dense reg.



I. bone

1. matrix – sim. to cartilage but more collagen

fibers and Ca++ salts

2. cells – osteoblastsosteocytes in lacunae

3. vascular and innervated

4. 2 types:

a. cancellous, or spongy bone

b. compact bone

J. blood

1. most atypical conn. tissue2. matrix: plasma, no fibers

3. cells – from hematopoietic stem cells

a. erythrocytes, leukocytes, platelets

4. transport

IV. Nervous tissue

A. makes up brain, spinal cord, nervesB. 2 cell types

1. neurons – respond to changes in RMP

a. cell body

b. axons – nerve fibers

c. dendrites

2. glial cells

V. Muscle tissueA. cells composed of myofilaments actin and myosin

B. 3 kinds

1. skeletal – pull on bone or skin

a. mutinucleated cells (called muscle fibers)

b. striated, voluntary



2. cardiac – heart wall

a. uninucleated branching cells, w/

intercalated disks

b. striated, involuntary

3. smooth – walls of hollow organs

a. fusiform uninucleated cells

b. non-striated, involuntary

c. gap junctions b/t cells

VI. Intercellular junctionsA. tight junctions

1. proteins between pl. memb. of adjacent cells

form seal

2. ensures that substances pass through

membranes, not between them

B. desmosomes

1. protein plaque w/ intermediate filaments2. in areas subject to mechanical stress

C. gap junctions

1. pores b/t cells for passage of ions, nutrients

2. intercalated disks, smooth muscle, embryo

VII. Glands

A. most made of epithelium

B. secretes secretionsC. endocrine glands - ductless

1. secrete hormones – endocrine sys.

D. exocrine glands - ducts

1. unicellular

2. multicellular

a. simple



b. compound

c. merocrine

d. holocrine

VIII. Membranes = epithelium + connective tissue

A. cutaneous membrane - skin

1. keratinized stratified squamous

2. dense irreg.

B. mucous membranes – line cavities open to exterior

1. stratified squamous or simple columnarw/ or w/out goblet cells; basement memb.

2. areolar - lamina propria

C. serous membranes – in ventral body cavities

1. simple squamous epi (mesothelium)

2. thin areolar

3. serous fluid – lubricates parietal and visceral

layers4. pleura, pericardium, peritoneum

IX. Tissue origins

A. stem cells

1. embryonic stem cells – totipotent

2. blastocyst after 4 days – pluripotent

3. adult stem cells

a. mitosis produces 1 new stem cell; otherdaughter cell differentiates

b. multipotent, unipotent

B. 3 layers formed during gastrulation of blastocyst

1. ectoderm→nervous tissue, epidermis

2. mesoderm→muscle, connective tissue,

endothelium and mesothelium



3. endoderm→mucous membranes

X. Tissue repair

A. inflammation

1. damaged tissue cells, macrophages, and mast

cells release vasodilating chemicals

2. leaky capillaries allow antibodies, clotting

proteins, WBCs to enter injured area

3. clot and scab forms

4. macrophages digest tissue debrisB. restoration of blood supply

1. granulation tissue rich in regenerating

capillaries forms

2. fibroblasts secrete collagen, growth factors

C. repair

1. epithelium regenerates, scar tissue forms

underneath

XI. Tissue death

A. senile and disuse atrophy

B. necrosis – from trauma, infection

1. gangrene

2. infarction

3. decubitous ulcer

C. apoptosis – programmed cell death

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Testing Your Recall 1-5, 7-20True or False, Testing Your Comprehension 1, 4, 5

Related Clinical Terms: anaplasia, dysplasia, hyperplasia, neoplasia, metaplasia

chapter 5 histology

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