Lesson 2.3 Tissues Chapter 2: Cells and Tissues. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Tissues are groups

Lesson 2.3

Tissues

Chapter 2: Cells and Tissues

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.

Tissues are groups of cells with similar structure that join together to perform a common function

- the study of tissues is Histology- tissues are classified into four main types;

1. Epithelial – lines and cover2. Connective - supports3. Muscle – generates force4. Nerve – conveys information

Types of Tissues


I. Epithelial Tissue

- Epithelia – tissues that cover the body and line body cavities

- Gland – tissues that secrete chemicals- endocrine gland tissue – secrete to

other parts inside the body- exocrine gland tissue – secrete to

outside world

Epithelial Tissue


- Four main functions of Epithelial Cells:1. protect body from physical damage2. control what enters and leaves the body3. provide sensory input4. secrete various substances

Epithelial Cell Shapes


- Apical surface – faces the outside world or lumen of a body cavity connected to outside world

- Basal surface – faces deeper body cells



Epithelia: Cell Layers and Shapes- Epithelia are classified by:

1. layers Simple = one layerStratified = multiple layers

2. shapeSquamous = almost flatCuboidal = height equal to widthColumnar = tall and skinnyIF multiple layers not same shape = classified as shape of the most apical cells



• simple– one layer

• stratified – more than one layer

• other– transitional

• stretchable

Epithelial Cell Arrangement


Simple Epithelia- Simple Squamous = single layer of flattened cells, allow for

rapid diffusion (thin)+ gas-exchanging cavities = alveoli in lungs+ lining of abdominal cavity+ endothelium, single layer, lining blood vessels/heart

- Simple Cuboidal = single layer typically involved in secretion or absorption

+ surround tubules in kidneys and secretory glands- Simple Columnar = single layer, secretory or absorptive

+ linings of ducts in kidneys, stomach and intestine+ may contain microvilli to increase surface area

Epithelial (Simple)


Stratified Epithelia- Stratified Squamous – where mechanical and chemical protection is most needed

+ skin – outside surfaces (apical) are dead and dying cells along with protein keratin. Provides a waterproof barrier to combat

dehydration.+ other apical surfaces include; mouth, throat, esophagus, anus, rectum

- Stratified Cuboidal = (rare) duct of sweat gland- Stratified Columnar = (rare) duct linings of pancreas and salivary glands

Epithelial (Stratified)


Epithelial (other)

Transitional epithelia

does not fit theotherclassifications

Example:Bladder


Glands – epithelial cells that secrete a substance(s) 1. Exocrine gland – secretes products to outside

worlda. unicellular exocrine glands – isolated cells in lining of respiratory and digestive tracts they secrete mucus to form protective cover over epithelium

Epithelial Glands


b. multicellular exocrine glands – two parts, secretory cells that make product and duct cells that connect gland cells to surface of epitheliumc. simple duct structure = single or compound – can be tubular or alveolar (spherical)

2. Endocrine gland secrete to interstitial space (spaces between

tissues)

Epithelial Glands


True or False?1. Connective tissue provides support.2. Transitional epithelial stretches.3. Cuboidal cells are flat.4. Stratified means more than one layer. 5. Epithelial glands secrete substances.

Review and Assessment


• functions– strengthens the body and organs– protects internal organs– maintains the shape of organs– provides rigid framework for muscles to pull

• fibers– collagen– reticular– elastic

Connective Tissue


• connective tissue proper– wide variety of locations and functions– plays a role in immune defenses

• cartilage– provides support and flexibility– minimizes friction

• bone tissue (osseous tissue)– provides framework, protects organs, supports body

• blood– provides transportation, regulation, and protection– carries oxygen and nutrients, and carbon dioxide

Classes of Connective Tissue


• connective tissue proper– loose– dense

• cartilage• bone

Types of Connective Tissue


• loose connective tissue– areolar–under epithelium – reticular–spleen– adipose–fat

Loose Connective Tissue


• dense connective tissue– regular dense–tendons – irregular dense–dermis– dense elastic–large

artery walls

Dense Connective Tissue


• chondroblasts• hyaline

– ends of long bones• elastic

– external ear • fibrocartilage

– intervertebral discs

Cartilage


• osseous tissue– protects organs– supports the body

Bone


• skeletal• cardiac• smooth

Types of Muscle Tissue


• central nervous system• peripheral nervous system• glial cells• neurons

Nerve Tissue


Match the following with 1–4 below: skeletal, collagen, nervous tissue, elastic cartilage.1. muscle tissue type2. external ear 3. fiber4. glial cells

Review and Assessment

Documents

Lesson 2.3 Tissues Chapter 2: Cells and Tissues. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Tissues are groups