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Chapter 4: Tissues and Membranes Theory Lecture Outline

Objectives

1. List the four main types of tissues

2. Define the function and location of tissues

3. Define the function and location of membranes

4. Define an organ and organ system

5. Relate various organs to their respective systems

6. Describe the processes involved in the two types of tissue repair

7. Describe the process of granulation

8. Define the key words that relate to this chapter

Introduction

Multicellular organisms are composed of many different types of cells. Each of these cells performs a special function. These millions of cells are grouped according to their similarity in shape, size, structure, intercellular materials and function. Cells so grouped are called tissues.

Tissues

• Tissues are groups of cells

A tissue is a group of cells that have similar structure and that function together as a unit. Four main tissue types are found in the body.

• Tissue types

a. Epithelial tissue

Tissue that protects the body by covering internal and external surfaces

b. Connective tissue

Connects organs and tissue allowing for movement and provides support for other types of tissue

c. Muscle tissue

Contains cell material which has the ability to contract and move the body

d. Nervous tissue

Contains cells that react to stimuli and conduct an impulse

Epithelial Tissue Table 4-1

Epithelial tissues are widespread throughout the body. They form a continuous layer covering of all body surfaces, line body cavities and hollow organs, and are the major tissue in glands. They perform a variety of functions that include protection, secretion (digestive juices, hormones, perspiration), regulation of materials across themselves (absorption, excretion, filtration, diffusion) and sensory reception.

• Classification of epithelia.

Epithelia are classified by their function, as either mucous or serous membranes, depending on the type of secretions produced. Epithelia are also classified according to cell shape and the number of layers in the tissue.

• Epithelial Functions and Shapes:

a. Covering and lining tissue

1. Squamous - flat, irregularly shaped. Line the heart, blood vessels, top layer skin

2. Cuboidal- cube shaped. Line kidney tubules, ovaries, and some secretory glands.

3. Columnar- elongated and often have cilia on outer surface. Line ducts in respiratory tract, intestines, and stomach lining.

b. Glandular or secretory tissue

1. Endocrine - form ductless glands that secrete hormones directly into bloodstream

2. Exocrine- secrete substances into ducts that are released outside the body. Mammary glands, sweat glands, and salivary glands are examples.

Connective Tissue Adipose Table 4-1

Connective tissues bind structures together, form a framework and support for organs and the body as a whole, store fat, transport substances, protect against disease and help repair tissue damage; they occur throughout the body. Connective tissues are characterized by an abundance of intercellular matrix with relatively few cells. Connective tissue cells are able to reproduce but not as rapidly as epithelial cells.

• Classification of connective tissue

a. Adipose tissue

b. Areolar (loose) tissue

c. Dense fibrous tissue

d. Supportive tissue

e. Vascular (liquid blood tissue)

• Functions

a. Adipose tissue

1. Stores lipid (fat)

2. Acts as filler tissue

3. Cushions, supports, and insulates the body

b. Areolar (loose) tissue

1. Surrounds various organs and supports both nerve cells and blood vessels which transport nutrient materials (to cells) and waste (away from cells)

2. Fibers embedded in areolar tissue include:

o Elastin tissue

o Collagen

c. Dense fibrous tissue

Types of dense fibrous tissue include:

1. Ligaments

Hold bones firmly together at the joints

2. Tendons

Attach skeletal muscles to the bones

3. Aponeuroses

4. Fasciae

d. Supportive tissue

1. Osseous (bone) tissue

Comprises the skeleton of the body, which supports and protects underlying soft tissue parts and organs and also serves as attachments for skeletal muscles

2. Cartilage

o Hyaline

o Fibrocartilage

o Elastic cartilage

e. Vascular (liquid blood tissue) tissue

1. Blood

2. Lymph

Muscle Tissue Table 4-1

• Cardiac (striated involuntary)

Involuntary muscle

• Skeletal (striated voluntary)

Voluntary muscle

• Smooth (nonstriated involuntary)

Involuntary muscle

Nervous Tissue Table 4-1

• Neurons (nerve cells)

a. Irritability

Ability of nerve tissue to respond to environmental changes

b. Conductivity

Ability to carry a nerve impulse (message)

Effects of Aging on Tissue

Aging changes are found in all of the body’s cells, tissues and organs and, in turn, effect the functioning of the body systems.

• Cells become larger and less able to divide and reproduce

• Increase in pigments and lipids inside cell

• Waste products accumulate in the tissue

o Cell membranes change and carbon dioxide and wastes have difficulty getting out

• Connective tissue becomes progressively stiff

• Many tissues lose mass and atrophy

Membranes

• Two thin layers of tissue together form a membrane

• Membrane classification

a. Epithelial membranes

b. Connective membranes

Epithelial Membranes

Two types or classifications – mucous or serous membranes

• Mucous membranes

Mucous membranes line surfaces and spaces that lead to the outside of the body (respiratory, digestive, reproductive and urinary) and produce a substance called mucus which lubricates and protects the lining

a. Respiratory mucosa (lines the respiratory passages)

b. Gastric mucosa (lines the stomach)

c. Intestinal mucosa (lines the small and large intestines)

• Serous membranes (parietal and visceral)

The serous membrane is a double-walled membrane lining closed body cavities that produces a watery fluid that allows the organs to move freely and prevents friction

a. Parietal membrane – outer part of the membrane that lines the cavity

b. Visceral membrane – part that covers the organs within

c. Types

1. Pleural membrane (lines the thoracic or chest cavity & protects the lungs)

2. Pericardial membrane (lines the heart cavity & protects the heart)

3. Peritoneal membrane (lines the abdominal cavity & protects abdominal organs)

Connective Membranes

Connective membranes consist of two layers of connective tissue

• Type or Classification

o Synovial membrane

1. Lines joint cavities

2. Secrete synovial fluid which prevents friction inside the joint cavity

Organs

• An organ is tissues grouped together to form a specific function

i.e. the stomach consists of vascular, connective, epithelial, muscular and nerve tissues

• Organs coordinate their activities to form a complete functional organism

• Organ system

o Group of organs that act together to perform a specific, related function

Organ Systems

Table 4-2 pg. 64 (encourage students to make flash cards indicating system, system function and organs involved)

The human body has 10 organ systems; together they coordinate their functions to form a whole, live, functioning organism

• Skeletal

• Muscular

• Digestive

• Respiratory

• Circulatory

• Excretory

• Nervous

• Endocrine

• Reproductive

• Integumentary

Disease and Injury to Tissue

• Infection – refers to the invasion of a microorganism causing disease resulting in inflammation

• Inflammation – is a protective response to an injury or irritant resulting in pain, swelling, redness and loss of motion

• Trauma – results from an external force causing tissue damage and injury

• Abnormal growth of cells – cause tissue damage and trauma

• Birth defects – can cause structural or functional changes of tissue

Tissue Repair

Repair of damaged tissues occurs continually during the everyday activities of living; however heart muscle tissue does not repair itself and nerve cell bodies destroyed by infection or injury do not grow back

• Two types of epithelial tissue repair

a. Primary repair

1. Takes place in “clean” wounds

2. Repair over a large skin area usually results in a typical scab to help in wound healing

3. Repair of deep tissues the edges of the wound must be brought or sewn together with sutures

b. Secondary repair

1. Repair of large open wounds with small or large tissue loss occurs through a process called granulation

2. Granulation - forms new blood vessels surrounded by young connective tissue and wandering cells of different types; fibroblasts will produce new collagenous fibers; bactericidal fluid is secreted to help reduce risk of infection

• Scar Tissue

As in any type of tissue repair, a certain amount of scar (cicatrix) tissue will form which depends on the extent of tissue damage

o Prevent or minimize excessive scar tissue

1. Areas must be kept in alignment

2. Nutrition

3. Vitamins

Table 4-3 pg. 66

Tissue and Organ Transplant

• Blood transfusions are an example of a tissue transplant

• All transplants (tissue and organs) must be cross-matched so recipient’s immune system

won’t attack the donated organ

• Rejection is main problem in organ transplants

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