BIO 210
CHAPTER 5
TISSUES – SUPPLEMENT
I.
INTRODUCTION
A. TISSUE – DEFINITION
- A Group of Similar Cells That Perform a Common Function(s)
B. MATRIX
- Nonliving Intercellular Substance
- Present in All Tissues; However, Tissues Differ in Kind/Amount
od Matrix
C. MAIN TYPES OF TISSUES
1. EPITHELIAL TISSUE
2. CONNECTIVE TISSUE
3. MUSCLE TISSUE
4. NERVOUS TISSUE
II.
EPITHELIAL TISSUE
A. TYPES AND LOCATIONS
1. MEMBRANOUS EPITHELIUM (COVERING/LINING)
- Forms Membranes That Cover and Line the Body
- Membrane That Covers the Body’s Surface - Skin
- Membranes That Line the Body
- Membranes That Line Closed Body Cavities (Thoracic,
Abdominal)
- Membranes That Line Vessels (Blood and Lymphatic
Vessels)
- Membranes That Line Systems That Open to the Outside
(Respiratory, Digestive, Urinary, Reproductive)
2. GLANDULAR EPITHELIUM
- Forms Glands
B. FUNCTIONS
1. PROTECTION
- Most Important Function of Membranous Epithelium
- ME Covers/Lines ? Protects
- Example: Skin
2. SENSORY FUNCTIONS
- ME Located in Sense Organs (Eye,Ear,etc.); Therefore, ME
Plays Important Role in the Sense Organ’s Function
3. SECRETION
- Most Important Function of Glandular Epithelium
- GE Forms Glands ? Glands Secrete
- Examples: Salivary Glands ? Saliva
4. ABSORPTION
- ME Located in Organs Involved in Absorption (i.e., ME Lines
Small Intestine ? Nutrient Absorption); Therefore, ME Plays
Important Role in Absorption by the Organ
5. EXCRETION
- ME Located in Organs Involved in Excretion (i.e., ME Lines
Kidney Tubules ? Excrete Urine); Therefore, ME Plays
Important Role in Excretion by the Organ
C. GENERALIZATIONS
1. LITTLE MATRIX, CELLS TIGHTLY PACKED
- P. Membranes Modified to Hold Cells Together
2. AVASCULAR
- Epi Tissues Are Without Blood Vessels, Get Oxygen, Nutrients
by Diffusion From Blood Vessels in Underlying Connective
Tissues
3. FREQUENT CELL REPRODUCTION
- The Cells in Epi Tissues Frequently Reproduce by Mitosis
- Reason: Epi Tissues Cover/Line, Subjected to Constant Wear
and Tear
4. MEMBRANOUS TYPE JOINED TO CONNECTIVE TISSUE (BELOW) BY
BASEMENT MEMBRANE
- A Basement Membrane “Glues” Membranous Epithelium to
Underlying Connective Tissue
D. CLASSIFICATION
1. MEMBRANOUS EPITHELIUM
- 2 Criteria Are Used to Classify ME
a. CLASSIFICATION BASED ON CELL SHAPE
1. SQUAMOUS
- Cells Flat, Platelike
2. CUBOIDAL
Cells Cube-Shaped
3. COLUMNAR
Cells Column-Shaped
4. PSEUDOSTRATIFIED COLUMNAR
Cells Column-Shaped But Odd B/C:
- Cells Are Different Heights
- Location of Nucleus Varies
Gives Impression of Layering, But It’s False
5. TRANSITIONAL
Cells Change Shape (Cuboidal to Squamous)
b. CLASSIFICATION BASED ON CELL LAYERS
1. SIMPLE
- Cells in One Layer
2. STRATIFIED
- Cells in More Than One Layer (Layered)
c. NAMES
1. SIMPLE SQUAMOUS EPITHELIUM
2. SIMPLE CUBOIDAL EPITHELIUM
3.
SIMPLE COLUMNAR EPITHELIUM
- Often Has Special Features: Goblet Cells, Cilia,
Microvilli
4. PSEUDOSTRATIFIED COLUMNAR EPITHELIUM
- Special Features Include Goblet Cells and Cilia
5. STRATIFIED SQUAMOUS EPITHELIUM (KERATINIZED)
- Cells Contain Keratin
6. STRATIFIED SQUAMOUS EPITHELIUM (NONKERATINIZED)
- Cells Lack Keratin
7. STRATIFIED CUBOIDAL EPITHELIUM
8. STRATIFIED COLUMNAR EPITHELIUM
9. STRATIFIED TRANSITIONAL EPITHELIUM
2. GLANDULAR EPITHELIUM
a. GLAND TYPES - 2 Major
1. EXOCRINE GLANDS
- Discharge Secretions into Ducts
- Ex: Sweat, Oil, Mammary, Digestive Glands
2. ENDOCRINE GLANDS
- Discharge Secretions Directly into Blood
(Ductless Glands)
- Ex: Endocrine Glands
b. STRUCTURAL CLASSIFICATION OF EXOCRINE GLANDS
- 2 Criteria Used to Classify Exocrine Glands by Structure
1. SHAPE OF DUCTS
a. TUBULAR: Tube-Shaped
b. ALVEOLAR: Sac-Shaped
c. TUBULOALVEOLAR: Both
2. COMPLEXITY OF DUCT SYSTEM (# Ducts Reaching Surface)
a. SIMPLE: 1 Duct Reaches the Surface
b. COMPOUND: More Than 1 Duct Reaches the Surface
c. FUNCTIONAL CLASSIFICATION OF EXOCRINE GLANDS
- Based on Method of Secretion
1. APOCRINE GLANDS
- Discharge by Collecting the Secretory Product
Near the Tip of the Cell and Pinching that Part
of the Cell Off
- Ex: Mammary Glands
2. HOLOCRINE GLANDS
- Discharge by Collecting Secretory Product
within the Cell, then Cell Ruptures
- Ex: Sebaceous Glands
3. MEROCRINE GLANDS
- Discharge Secretory Product Through the
Plasma Membrane of the Cell By Exocytosis
- Most Common
III. CONNECTIVE TISSUE
A.
GENERAL FUNCTIONS
1. CONNECTS
- Tissue to Tissue: CT Lies B/T Epithelial and Muscle Tissue
- Organ to Organ: CT (Ligaments) Connects Bone to Bone;
CT (Tendons) Connects Muscle to Bone
2. SUPPORTS
- Bone Tissue (CT) Forms Bones
3. TRANSPORTS
- Blood (CT)
4. PROTECTS
- Blood (Sp. WBC’S)
B.
GENERAL CHARACTERISTICS
1. MOST WIDESPREAD AND VARIED OF TISSUES
- In/Around Most Organs
- Exists in Many Forms
2. MUCH MATRIX WITH FEWER CELLS
- Matrix Predominates, Cells Widespread (Opposite From
Epithelial Tissue)
3. MATRIX OFTEN CONTAINS PROTEIN FIBERS (COLLAGENOUS,
RETICULAR, AND/OR ELASTIC)
- Protein Fibers Produced By Cells in the CT
- Most Common Protein Fibers
- Collagenous: White, Strong
- Reticular: Delicate, Present in Networks
- Elastic: Stretchy
4. MATRIX AND FIBERS (IF PRESENT) DETERMINE THE UNIQUENESS OF
EACH TYPE OF CONNECTIVE TISSUE
- CT’s Are Diverse B/C Matrix and Fibers in Each Type of CT
Are Diverse
- Examples:
- Matrix May Be Hard (as in Bone), Gel-Like (as in
Cartilage), or Liquid (as in Blood)
C.
- Protein Fibers: CT May Contain Just Collagenous Fibers
TYPES
1. FIBROUS CONNECTIVE TISSUES
- Protein Fibers Predominate
a. LOOSE (AREOLAR) CONNECTIVE TISSUE
- One of the Most Widely Distributed of All Tissues
- Connects Many Structures
b. ADIPOSE TISSUE
- AKA Fat Tissue
c. RETICULAR TISSUE
- Contains Reticular Fibers, Forms Framework of Many
Organs of the Lymphatic System
d. DENSE FIBROUS TISSUE
- So Named B/C It’s Densely Packed With Fibers, Composes
Ligaments, Tendons, and Dermis of the Skin
2. BONE TISSUE
- Highly Specialized CT, Matrix is Hard B/C Contains a
Predominace of Minerals
3. CARTILAGE
- Matrix is Gel-Like, 3 Types
a. HYALINE CARTILAGE
- Shiny, Most Prevalent
b. FIBROCARTILAGE
- Strongest, Predominace of Collagenous Fibers
c. ELASTIC CARTILAGE
- Stretchy, Predominace of Elastic Fibers
4. BLOOD
- Extremely Unusual CT B/C Matrix is Liquid
IV.
MUSCLE TISSUE - TYPES
A.
SKELETAL (STRIATED, VOLUNTARY) MUSCLE TISSUE
- Location: Composes Skeletal Muscles
- Striated: "Cross Striations" (Stripes) Seen Under the
Microscope
- Voluntary: Under Conscious (Willed) Control
B.
SMOOTH (NONSTRIATED, INVOLUNTARY, VISCERAL) MUSCLE TISSUE
- Nonstriated: No "Cross Striations" Seen Under the Microscope
(Looks Smooth Under Microscope)
- Visceral: Located in the Viscera (Hollow Organs in Many Systems
i.e., Cardiovascular, Respiratory, Digestive, Urinary, and
Reproductive)
- Involuntary: Not Under Conscious Control
C.
CARDIAC (STRIATED, INVOLUNTARY) MUSCLE TISSUE
- Location: Composes the Wall of the Heart
- Striated Like Skeletal Muscle Tissue
- Involuntary Like Smooth Muscle Tissue
V.
NERVOUS TISSUE
- Composed of Neurons (Nerve Cells) and Neuroglia (Supporting Cells)
- Forms Organs of Nervous System
VI.
TISSUE REPAIR
- Tissues Have Varying Capacities to Repair Themselves
- Epithelial and Connective Tissues have the Greatest Capacity to
Repair Themselves
- Muscle and Nervous Tissues have a Limited Capacity for Repair
- Damaged Tissue Regenerates (Repairs) or is Replaced by Scar Tissue
Regeneration: Growth of New Functional Tissue
Scar Tissue: Growth of Fibrous Connective Tissue (Occurs When
the Injury is Large and Deep)
VII.
BODY MEMBRANES - 2 Major Types
A. EPITHELIAL MEMBRANES
- Composed of Membranous Epithelium
- Most Common Type of Body Membrane
- 3 Kinds
1. CUTANEOUS MEMBRANE : Skin
2. SEROUS MEMBRANES
- Line and Cover Organs in Closed Body Cavities
(Thoracic, Abdominopelvic)
- One Continous Sheet that Lines Cavity (Parietal Membrane)
and Covers Organs (Visceral Membrane)
- Secrete a Serous (Watery) Fluid (Lubrication)
3. MUCOUS MEMBRANES
- Line Body Systems that Open to the Exterior
(Respiratory, Digestive, Urinary, Reproductive)
- Secrete Mucous (Thick, Provides Protection)
B.
CONNECTIVE TISSUE MEMBRANES: SYNOVIAL MEMBRANES
- Composed of Connective Tissue
- Example: Synovial Membranes
- Location: Line Joints
- Secretes Synovial Fluid (Lubrication)