KIN 223 CHAPTER 5 LESSON OBJECTIVES

5.1.1 Describe the common features of the epithelial tissue.

• Cellularity: Composed of tightly packed cells

• Polarity

- Apical surface (think of your skin): Exposed to external environment/internal body space 

- Basal surface (deepest surface): Epithelium attached to connective tissue 

• Attachment to the basement membrane: Barrier between epithelium and connective tissue 

• Avascularity: Lack of blood cells 

• Extensive innervation: Richly innervated, or lots of nerves 

• High regeneration capacity: Cells heal easily  

5.1.2 Explain the four functions of the epithelial tissues.

1. Physical protection: 

• Protects from dehydration, abrasion, destruction 

2. Selective permeability: 

• Allows passage of some substance (in or out) while preventing passage of others 

3. Secretions: 

• Some cells are specialized 

4. Sensations: 

• Supply information to nervous systems 

5.1.3 Name the classes of epithelia based on cell layers and cell shapes.

• Cell layers:

- Simple epithelium: one cell layer 

-Stratified epithelium: two or more layers of epithelial cells 

-Pseudostratified: closely packed cells which appear to be arranged in layers

• Cell shapes:

- Squamous cells (squished): flat, wide, and irregular in shape 

-Cuboidal cells (cube-shaped): about as tall as they are wide 

-Columnar cells (column-shaped): slender and taller than they are wide 

5.1.4 Identify and describe the structure, function, and location of each type of epithelial tissue.

• Simple Squamous 

-A single layer of flattened cells 

-Function: Rapid diffusion and filtration of molecules across the surface 

-Location: air sacs of lungs (alveoli), vessel walls (endothelium), and serous membranes (mesothelium)

• Simple Cuboidal 

-A single layer of cells about as tall as wide

-Function: Absorption and secretion

-Location: Lining of kidney tubules and thyroid glands

• Simple Columnar 

-A single layer of tall narrow cells

-Function: Absorption and secretion 

- Has two forms 

1.Nonciliated 

- Location: lines digestive tract (stomach, intestines)

- Has microvilli 

- Has unicellular glands called goblet cells (makes mucin which hydrates   

to produce mucus)

2. Ciliated 

-Location: lining of bronchioles (air passageways) of the lungs and uterine 

Tubes

• Pseudostratified Columnar 

- A single layer of tall cells that appears stratified 

- Has two forms 

1. Ciliated 

- Location: lining of larger airways of respiratory tract (nasal cavity, part of 

pharynx, part of larynx, etc) 

2. Nonciliated 

- Location: male urethra and epididymis 

- Rare and lack cilia 

• Stratified Squamous 

-Multiple layers; upper layers of flattened cells 

-Function: protection of underlying tissue from abrasion

-Has two forms 

1. Keratinized (it kills, on the skin)

-Location: epidermis of the skin 

- Cells lack nuclei, filled keratin, and die 

2. Nonkeratinized (not within the skin) 

-Location: lines oral cavity 

-All cells alive 

-Kept moist with secretion (saliva and mucus)

• Stratified Cuboidal 

-Two or more layers; cells about as tall as wide 

- Function: Protection and secretion 

- Location: Ducts of most exocrine glands and ovarian follicles

• Stratified Columnar 

-Two or more layers; cells about as tall as wide 

- Function: Protection and secretion 

- Location: Large ducts of salivary glands; conjunctiva covering the eye; lining of the membranes part of male urethra

• Transitional Columnar Epithelium 

-Multiple layers of cells that change shape when stretched

- Limited to urinary tract 

- In stretched state 

5.1.5 Define glands.

• Glands: Individual cells or multicellular organs composed of epithelial tissue 

5.1.6 Distinguish between endocrine and exocrine glands.

• Endocrine glands (inside): 

-Secrete hormones into blood (it secrete things that are going to stay inside) 

• Exocrine glands (exiting):

-Epithelium in CT 

-Connected with epithelial surface by duct (pathway or tube)

Swear, mammary, and salivary glands

5.1.7 List exocrine gland types based on both anatomic form and physiologic method of secretion.

• Anatomic form 

-Simple glands: A single, unbranched duct 

-Compound glands: Branched ducts

-Tubular glands: Secretory portion and duct of the same diameter 

-Acinar glands: Secretory portions forms expanded sac 

-Tubuloacinar gland: Both tubules and acini 

• Physiologic method of secretion 

-Merocrine glands (a vesicle, like a little backpack): package secretions into vesicles, released by exocytosis 

-Apocrine glands: Apocrine membrane pinches off a piece 

- Apocrine pinches off a piece 

-Holocrine glands: Ruptured cell becomes secretion 

- The whole cell ruptures 

5.2.8 Describe the three components of connective tissue.

• Cells

-Most cells are not in direct contact with each other

- Has few cells 

-It has two classes

1. Resident

- Stationary, housed in CT

2. Wandering

-Move through CT 

-Protect the body from harmful agents 

Types of leukocytes, white blood cells 

• Protein fibers 

-Provide structural support and strength

-It had three classes 

1. Collagen fibers

- Most abundant

- Providing tensile strength and making tissues resistant to stretching

2. Reticular fibers

-Thin

-Branching fibers that form a supportive network for organs like the spleen and lymph nodes

3. Elastic fibers

-Made of elastin

-These fibers allow tissues to stretch and recoil

-Found in areas ne

eding flexibility ike the skin, lungs, and blood vessels

• Ground substance 

-Molecular (not cellular) material produced by CT cells (outside of the cell) 

Residence of CT cells and protein fibers 

Ground substance + protein fibers = extracellular matrix (outside the cell of CT)

5.2.9 Give examples of resident cells and wandering cells in connective tissue proper.

• Fibroblasts (blast = build-up)

- Produce fibers and ground substance of extracellular matrix

-Most abundant resident cells in CT proper 

• Adipocytes (fat cells; cyte = cell)

-Appear in small clusters in some types of CT proper

-Adipose connective tissue - dominant area of large clusters 

• Mesenchymal cells 

-Embryonic stem cell 

-Divides to replace damaged cells 

• Fixed macrophages 

-Relatively large, irregular-shaped cells 

5.2.10 Name three types of protein fibers found in connective tissue.

• Collagen fibers

-Strength 

-Unbranched, cable-like long fibers (rope) 

-Pink lines

• Reticular fibers 

-Similar to collagen fibers but thinner 

-In the stoma of some organs, like the lymph nodes 

• Elastic fibers

-Stretch and recoil easily

-Found in skin, walls of arteries 

-Think of stretching your socks or underwear 

-Thin purple lines 

5.2.11 List three types of molecules that may be found in ground substance.

• Glycosaminoglycans (GAGs)

-Large molecule in ground substance

- Attracts cations, water follows

• Proteoglycans (Protein added to sugar) 

-Formed with GAG linked to a protein 

• Glycoproteins (Proteins adding to sugar)

- Proteins with carbohydrates attached 

5.2.12 Describe the functions of connective tissues.

• Protecting 

-Cells of the immune system and blood protection against toxin and tissue injury, as well as from microorganisms

-Bones protect underlying structures from injury 

• Support and structural framework 

- Connective tissues like bones and cartilage provide the body’s structural support and maintain its shape 

• Binding structures 

-Tendons, ligaments, and other connective tissues bind organs and tissues together

• Storage 

-Adipose tissue stores energy in the form of fat and also provides insulation and cushioning

• Transport 

-Blood transports substances throughout the body, such as gasses, nutrients, enzymes, hormones, and cells of the immune system 

• Immune protection 

- Host immune cells: Blood and lymph carry white blood cells to fight pathogens 

- Support inflammation: Help trigger inflammation to combat infections and repair tissues 

- Act as barriers: Skin and mucous membranes block harmful microorganisms 

5.2.13 Compare and contrast mesenchyme and mucous connective tissue.

• Mesenchyme

-Adult CT has mesenchymal stem cells

• Mucous 

-Found in the and supports the umbilical cord only 

5.2.14 Compare and contrast the general characteristics of connective tissue proper, supporting connective tissue, and fluid connective tissue.

• All connective tissue come from mesenchyme (starting origin) 

• Loose connective tissue

1. Areolar 

-Loose organization of collagen and elastic fibers

-Location:Papillary layer of the dermis 

-Function: Binds skin and some epithelial to deeper tissue (dermis)

2. Adipose 

-Closely packed adipocytes 

-Location:Subcutaneous layer

-Function:Stores energy 

3. Reticular

-Meshwork of reticular fibers

-Location:Spleen, lymph nodes, bone marrow 

-Function: supportive framework

• Dense connective tissue 

1. Dense Regular 

-Tightly packed, parallel collagen fibers 

-Location:Ligaments and tendons 

-Function:Attaches bone to bone (ligaments) and muscle to bone (tendons)

2. Dense Irregular

-Clumps of collagen fibers extended in all directions 

-Location:Dermis of the skin 

Function:Withstands stress applied in all directions

3. Elastic CT 

-Branching, densely packed elastic fibers

-Location:Walls of large arteries 

Function:Stretches and recoils 

• Supporting Connective Tissue 

-Cartilage 

1. Hyaline cartilage 

-Most common type 

-Location:The end of long bones

-Function:Provide support

2. Fibrocartilage 

-Weight-bearing cartilage resists compression 

-Location:Intervertebral discs

-Function:Acts like a shock absorber in some joints 

3. Elastic cartilage 

-Flexible and springy 

-Location:External ear

-Function:Maintains shape while permitting flexibility 

• Fluid Connective Tissue 

1. Blood

-Fluid CT with formed element (we make the stuff in blood) 

-Erythrocytes, leukocytes, platelets

-Liquid ground substance is plasma, which dissolves proteins 

2. Lymph

-Derived from blood plasma

-No cellular components 

-Returns to bloodstream 

5.2.15 Identify and describe the structure, function, and location of the specific types of connective tissue.

5.3.16 Compare and contrast the structure, function, and location of the three types of muscle tissue.

• Skeletal 

-Striated and voluntary, alternating light and dark bands called striations, multinucleated 

-Location:Attaches to bone or sometimes skin 

-Function:Responsible for moving skeleton 

• Cardiac 

-Visible striations, cells short and branching, connected by intercalated discs, involuntary

-Location: heart wall (myocardium)

-Function: pumps blood through heart and blood vessels

• Smooth

-Visceral, involuntary, lacks striation, appears smooth, short with one nucleus

-Location: walls of internal organs

-Function: move and propels through internal organs

5.4.17 Describe the structure, function, and locations of nervous tissue.

• Location: brain, spinal cord, nerves

• Function: neurons receive, transmit, and process nerve impulses

5.5.18 Define an organ and provide an example of the tissues that may compose an organ.

• Organ: two or more tissue types that work together to perform specific complex functions

• Ex: stomach, contains all four tissue types 

• Lined by epithelium 

• Areolar and dense CT in walls

• 3 layers of smooth muscle in the walls

• Abundant nervous tissue

5.5.19 Identify and describe the structure and function of mucous, serous, cutaneous, and synovial membranes.

• Mucous

-Lines compartments that open to the external environment 

-Include digestive, respiratory, urinary, and reproductive

-Performs absorptive, protective, and secretory functions

-Has epithelium and underlying CT

• Serous

-Lines of body cavities that DO NOT open to the external environment

-Is simple squamous epithelium 

-Produces thin, watery serous fluid (parietal and visceral layers)

-Comes from blood plasma

-Reduces friction

• Cutaneous

-Covers the external surface of the body

-Composed of keratinized stratified squamous epithelium, underlying CT

-Protects internal organs and prevents water loss

• Synovial 

-Line some joints in the body

-Composed of

-Areolar CT

-Covered by squamous epithelial cells

-Synovial fluid is made by epithelial cells

-Reduces friction

-Distributes nutrients to cartilage

5.6.20 Describe the three primary germ layers and the tissues to which they give rise.

• Three primary germ layers (create everything in your body when developing as an embryo) 

• Ectoderm (Epithelial tissue on the outside; epidermis of skin, hair, nails, sweat glands)

-Makes you aware of things

-Includes the nervous system, all of our nerves

-Nervous tissue, sense organs

Mesoderm

-All muscle (cardiac, skeletal, smooth, etc)  and connective tissue

-Includes kidney, internal reproductive organs, spleen (inside layers)

• Endoderm (Epithelial tissue on the inside; everything that lines your blood vessels or respiratory tract)

-Is all the organs that are completely inside of you

-Not exposed to the outside like our lungs

-Liver, gallbladder, pancreas

5.6.21 Describe how tissues may change in form, size, or number of cells.

• Hypertrophy: increase in SIZE of existing cells of a tissue

• Atrophy: shrinkage of tissue by decreasing in cell number or size

• Hyperplasia: increase in NUMBERS of cells of a tissue 

• Metaplasia: change due to epithelial adapting to an environment 

• Think of smoking, lungs aren’t used to that kind of environment

• Dysplasia: abnormal/bad tissue development 

• Neoplasia: tissue growth out of control 

• Necrosis: tissue death due to irreversible tissue damage 

5.6.22 List some changes that occur in tissues with age.

• All tissue change with aging 

• The structure and chemical composition of many tissues change/altered 

1. Epithelia things 

2. Ct loses pliability and resilience 

3. Collagen decines 

4. Bones become brittle 

5. Muscle atrophy