chapter 4: complete epithelial, connective, muscle and nervous tissues

8/10/2019 Chapter 4: Complete Epithelial, Connective, Muscle and Nervous Tissues

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The Tissue Level ofOrganization

Chapter 4

Dr. Aglaia Chandler

BIOL 2101


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Types of Tissues

I. Epithelial Tissues: cover external & internalsurfaces

II. Connective Tissues: fill internal spaces III. Muscle Tissue: contracts (movement)

IV. Neural Tissue: conducts electrical impulses& carries information


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I. Epithelial TissuesA. Characteristics

1. cells are attached to each other2. one surface is not attached to other cells

3. basal surface attached to connective tissue by basement membrane

4. avascular

5. epithelial cells either form sheets that cover body surfaces and line cavitiesand organs or form glands

B. Functions1. protection - intact epithelium serves as a barrier

2. transport - epithelial cells selectively move materials between compartments

3. produce glandular secretions


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C. Intercellular connections - epithelial cells are held together by1. intercellular cement

2. cell junctions -

a. tight junctions prevent the movement of molecules between the cells

b. gap junctions - small channels between adjacent cells allow the passage

of ions

c. desmosome - proteins anchored inside the cells hold two adjacent cellstogether

D. Surface Modifications1. Microvilli - fingerlike extensions of cell membrane that increase the

cells surface area2. Cilia - hairlike extensions of the cell membrane that move materials across

the cells surface

I. Epithelial Tissues


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E. Basement membrane network of protein fibers

holds epithelium and connective tissue together

acts as a filter

F. Repair epithelial cells have short life spans and are constantly replaced

epithelial tissues are easily repaired

I. Epithelial

Tissues

G. Types of epithelial sheetsthere are three cell shapes: flat (squamous), cuboidal, columnar

they can be arranged in single (simple) or multiple (stratified) layers


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G. Types of epithelial sheetsthere are three cell shapes: flat (squamous), cuboidal, columnar

they can be arranged in single (simple) or multiple (stratified) layers

I. Epithelial Tissues


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T f E ith li l Sh t


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2. Simple Cuboidal Epithelium

LowHigh

Types of Epithelial Sheets

Location: lines the lumen of ducts,

portions of kidney tubules, thyroid gland

Function: secretion & absorption


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Lung: simple squamous epithelium


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1. Follicle Cells2. Thyroglobulin Colloid

1

2



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3. Simple Columnar Epithelium

LowHigh


Location: lining of stomach, intestine,

gallbladder, uterine tubes, collecting duct

of kidneysFunction: secretion (mucus), absorption,

protection, movement of mucous layer

Sometimes have goblet cells (glands that secrete mucus) andcilia that move mucus or reproductive cells (ovum in the uterine

tubes)


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1. goblet cell

2. nucleus of columnar cell3. microvilli


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4. Pseudostratified Ciliated ColumnarEpithelium

cilia

cilia

Goblet cells


Location: lines the nasal cavity, trachea, bronchi

portions of male reproductive tract

Function: secretion, protection, movement of mucus



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4. Pseudostratified Ciliated Columnar

Epithelium

A: basement membraneB: cilia

C: nucleus

yp p

Have goblet cells (glands that secrete mucus)

--only tall cells reach the

apical surface

--short cells give rise totall cells

-- nuclei at different levels


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Trachea


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5. Stratified Squamous Epithelium

B: flattened cell at surface

Location: surfaces of skin, lining of mouth, throat, esophagus, rectum,

anus, and vaginaFunction: protection only

Types: nonkeratinized (esophagus) and keratinized ( skin)

St tifi d C b id l & C l E ith li R T


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Sweat Duct- Stratified Cuboidal ( swet glands,

mammary & salivary glands)

Stratified Cuboidal & Columnar Epithelia---Rare Types



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6. Transitional Epithelium

A: Umbrella cellsUreter

It is similar to the stratified squamous epithelium but has the ability to stretch

Location: lines the urinary bladder, ureters and parts of kidneysFunction: permits distension


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Transitional-Urinary Bladder


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Major Types


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4. Bone cells are osteocytes

cell cavities are called lacunae, which are connected by tiny canals

(canaliculi)_

matrix consists of collagen fibers (35%) surrounded by crystals ofcalcium phosphate (65%)

collagen provides tensile strength and minerals provide compression

strength

remodeling is constant damaged tissue is easily repaired

Major Types

C.T. Proper


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1. Areolar Connective

In the watery matrix (ground substance) observe the nuclei of fibroblasts (A),

collagen fibers (B) and elastic fibers (C).

Locations: beneath the skin and around blood vessels, muscles and nerves

Functions: binds one tissue to another (as skin connects to muscle),protection and nourishment to the organs and structures it binds, and stores "body fluid"

Loose Areolar


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1. Collagenous fibers2. Elastic fibers

3. fibroblast

C.T. Proper


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2. Dense Regular Connective

The micrograph above is at very low magnification.

To the left, at a much higher magnification, the fibroblasts (A)

are more clearly observed between the parallel collagenous fibers (B).

Locations: tendons and ligamentsFunctions: strong flexible support


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Tendon

C.T. Proper


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3. Elastic Connective

This section of aorta shows a tremendous number of elastic fibers (A).

The fibroblasts are not visible. The light pink in this tissue is smooth muscle.

Location: large arteries, bronchial tubes

Function: Elastic fibers can stretch l 1/2 times their length and then recoil.

These fibers will provide elasticity to tissues.

C.T. Proper


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4. RETICULAR CONNECTIVE

Observe that the reticular fibers (A) form a network or lattice in this spleen tissue.

Do not confuse this tissue with the elastic connective tissue

which has fibers that are parallel.

Locations: spleen, lymph nodes, liverFunction: gives support to soft organs


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Aorta- an example of elastic tissue

C.T. Proper


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5. ADIPOSE

Above observe adipose at a low magnification. The cells appear empty.At the left observe that the nucleus (A) is pushed to the side of the cell

giving the cell the appearance of a signet ring. Cells are filled with fat globules (B).

Locations/functions:

-- Anywhere there is an empty space in the body fat is stored as a source of energy

and may provide insulation.--The kidneys are correctly positioned and cushioned by adipose tissue.

--The eye is cushioned in the orbit by adipose.


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Fluid CT: Blood


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Fluid CT: Blood

lymphoc

yte

neu

trophil

monocyte

platelets

Erythrocytes: Red blood Cells (RBC)

Leukocytes: White blood cells (WBC): neutrophil, basophil, eosinophil, lymphocytemonocyte

Thrombocytes: platelets

Blood


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Blood

eosinophil

basophil

neutrophil


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Hyaline Cartilage


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2 Elastic CartilageCartilage


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2. Elastic Cartilage

Elastic cartilage is contained within the bracket at the left.This tissue is more highly magnified at the right.

The chondrocytes (A) are contained in lacunae (C).

The matrix (B) contains abundant elastic fibers.

These fibers give great flexibility to this tissue.

Locations: ear, auditory canal, epiglottisFunctions: flexible support


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Elastic Cartilage

1. Chondrocyte in lacunae2. Elastic fibers

3 FibrocartilageCartilage


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3. Fibrocartilage

These micrographs are of intervertebral disc tissue.At the left fibrocartilage is found in the area between the parallel lines.

This cartilage type is recognized by chondrocytes (A) oriented in rows.

Even when the tissue is highly magnified (as at the right), the lacunae,

which hold the chondrocytes, are not visible. The matrix (B) contains

numerous fine collagen f ibers. These fibers give the tissue durability.Locations: pubic symphysis, intervertebral discs

Functions: supports, withstands compression


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FibrocartilageArrow is pointing to chondrocyte in lacunae


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Fibrocartilage

BoneSupporting Connective Tissue:


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Bone

In the compact bone micrograph at the left, several complete osteons are visible.

In the center of the osteon is the central canal (A)

which hold the blood vessels and a nerve. These canals are surrounded

by concentric rings of inorganic matrix, the lamellae (B).

Between the lamellae are bone cells, the osteocytes (C) located in lacunae.

Nutrients diffuse from cell to cell through the canaliculi (D).

Location: skeleton

Function: framework, protection


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Bone-Haversian System

III Muscle Tissues


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III. Muscle Tissuesspecialized for contraction (shortening)moves the body or materials through the body

shortening caused by interaction between proteins (actin and myosin)

inside the muscle cells

Types of Muscle Tissues

A. Skeletal attached to the skeleton

only contract when stimulated by somatic (voluntary)nerve signals

partial repair can occur in damaged tissue


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A Skeletal Muscle


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A. Skeletal Muscle

Cells are long, cylindrical, striated, and multinucleate


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Skeletal Muscle


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B Smooth Muscle


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B. Smooth Muscle

Cells are short, spindle-shaped, and non-striated, with a single, central nucleus

B. Smooth Muscle


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B. Smooth Muscle

B. Smooth Muscle


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B. Smooth Muscle


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C. Cardiac Muscle


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C. Cardiac Muscle

Cells are short, branched, and striated, usually with a single nucleus.

Cells are interconnected by intercalated disc (gap junctions).


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Cardiac Muscle

Cardiac Muscle: Gap Junctions


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p

Cardiac Muscle: Gap Junctions


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p


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C. Cardiac Muscle: Striations


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Cardiac Muscle

IV. Neural Tissue


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A.Consists of:

1. neurons that conduct electrical signals throughout the body

2. neuroglia that perform support functions for the neurons

B. coordinates the activity of most other organs


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chapter 4: complete epithelial, connective, muscle and nervous tissues

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