Tissue A collection of cells that perform related functions, and are similar in structure, or a mass

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Ch 4 Tissues

• Tissue A collection of cells that perform
  related functions, and are similar in structure,
  or a mass of like cells
• Histology The study of tissues
• The Four Primary Tissue Types
• Epithelial
• Connective
• Muscular
• Nervous

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Epithelial Tissue

• Epithelium / -a cell layer (barrier)
• Epi on or upon
• Protection covering or lininginside and out
• Permeability control selective secretion and
  absorption
• Sensation touch receptors etc. and
  neuroepithelium of special senses
• Glands secretory structure
• Specialized secretions
• Saliva, hormones, many others

• The Four Primary Tissue Types
• Epithelial
• Connective
• Muscular
• Nervous

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Characteristics of Epithelia p 69

• Cellularity almost no IC space
• Specialized contacts
• Polarity
• Support by CT (esp. skin)
• Avascular
• Regeneration

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Structural Characteristics of Epithelia
apical
Cellularity Cell to cell contacts Polarity
(sometimes) Basement Membrane Support by
connective tissue Avascular (esp.
epidermis) Regeneration/repair
basal
BM
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Polarity of (some) Epithelial Cells
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Classification of Epithelia

• The function of the epithelium determines which
  type.
• Typically classified according to1. Number of
  cell layers Simple vs. Stratified2. Shape of
  cell Squamous, cuboidal, columnar

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Types of Epithelia

• Simple one layer
• Simple squamous
• Simple cuboidal
• Simple columnar
• Pseudostratified
• PCCE

• Stratified multiple layers
• Squamous
• Cornified or non-
• Cuboidal
• Transitional

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Simple Squamous Epithelium

• Location
• Lining of ventral body cavities, e.g. peritoneum
• Lining of blood vessels (endothelium)
• Alveoli of lung
• Bowmans Capsule

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Lung
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Function of Simple Squamous E.

• Friction reduction (cavity lining)
• Blood vessel permeability control (capillaries
  and Bowmans capsule)
• Gas absorption and secretion (lung)
• Not protectiveonly one cell thick

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Simple Cuboidal Epithelium

• Function
• Secretion
• Absorption
• Location Lining of ducts
• e.g., kidney tubules
• Glands (salivary, pancreas, thyroid)

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Kidney tubule
Thyroid Follicle
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Simple Columnar Epithelium

• The classic epithelium
• Function
• Secretion
• Absorption
• Location
• GI tract
• Many excretory ducts
• Cilia (uterine tube)
• Microvillus (small intestine)

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Pseudostratified Ciliated Columnar Epithelium

• FunctionMucociliary Blanket
• Mixture of cell types ? nuclei located at various
  distances from surface. Yet all cells contact BM
• LocationDucts of Respiratory tract
• i.e., trachea and bronchi

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Stratified Squamous Epithelium

• FunctionProtection against abrasion, pathogens,
  chemicals, heat/cold
• Keratinized vs. non-keratinized
• Location ? Where we need protection!
• Skin surface
• Entrances/exits of body, e.g. mouth, vagina

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Nonkeratinized stratified squamous epithelium
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Keratinized Stratified squamous epithelium (Thick
skin)
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Stratified cuboidal and columnar quite rare,
found in glands and ducts
Sweat gland
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Transitional Epithelium

• Function ?
• Extreme expansion recoil
• Layered appearance due to overcrowding. All cells
  contact BM.
• Location ?
• Bladder, ureters, renal pelvis

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stretched
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Glandular Epithelia
Types of Glandular Secretions

• Exocrine
• Glands have ducts
• Secretion to the outside of the body
• Simple or compound

• Endocrine
• Glands have no ducts
• Hormones (into the bloodstream)

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Ch 4 Tissues, contd

• Histology The study of tissues
• Tissue A collection of cells that perform
  related functions, and are similar in structure
• The Four Primary Tissue Types
• Epithelial
• Connective
• Muscular
• Nervous

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Connective Tissue Supports, protects, binds
tissues

• Structural characteristics
• Specialized cells, few in number
• Extracellular matrix
• fibers (collagen)
• Ground substance (fluid-like)

• The Four Primary Tissue Types
• Epithelial
• Connective
• Muscular
• Nervous

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Functions of C.T.

• Structural framework for body
• Transport of fluids and dissolved materials
• Support and protection for organs
• Energy storage (fat)
• Defense

• The Four Primary Tissue Types
• Epithelial
• Connective
• Muscular
• Nervous

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Classification of C.T.

• C.T. proper (viscous matrix with fibrous,
  insoluble proteins)
• Areolar (loose), reticular, dense, adipose
• Supporting C.T. (gelatinous or solid matrix)
• Cartilage, bone
• Fluid C.T. (watery matrix with dissolved
  proteins)
• Blood, lymph

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Classification of Connective Tissue
This is slightly different from p 81
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Connective Tissue Proper - viscous EC matrix 1.
loose (areolar) C.T. 2. reticular C.T. 3. dense
C.T. 4. fat
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1. Loose (areolar)

• Most widespread
• Beneath most epithelia
• Think dermis!!!
• Types of Fibers
• Collagen
• Elastic
• Reticular

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1. Loose (areolar)

• Ground Substance
• Similar to plasma
• Leaked from capillaries
• AKA ECF, interstitial fluid
• Defense
• Macrophages
• Plasma Cells
• Mast Cells
• Other WBC

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2. Reticular

• Resembles areolar CT, but
• Reticular fibers only
• reticulum network
• Bone marrow, spleen

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3. dense C.T.

• Irregular
• Collagen fibers in many directions
• Resist multi-directional tension
• Joint capsules
• Regular
• Very parallel fibers of collagen
• Tendons
• Elastic
• Elastic fibers gt collagen
• Arterial walls

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4. fat

• AKA adipose
• Cells are swollen with fat
• Prominent in hypodermis
• Intercellular matrix is obscured
• Storage of energy

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Supporting C.T.

• Cartilage
• 1. Hyaline
• 2. Elastic
• Ear (auricle), larynx
• 3. Fibrocartilage
• Intervertebral discs
• Bone (Chapter 6)
• Mineral matrix

Check Chapt 6, p 125
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1. Hyaline Cartilage

• I.C. Matrix appears homogeneous
• Chondroblasts and chondrocytes in lacunae
• Articular cartilage
• Tracheal rings

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2. Elastic cartilage
3. Fibrocartilage

• More elastic fibers
• Ear

• IV disk
• Symphysis pubis

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Bone (chap 6)

• The I.C. matrix is mineral, not fibrous

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Fluid C. T.

• Blood (Ch 17)
• Lymph (Ch 20)

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Study individual types of c.t. in lab
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Membranes Combination of Epithelia C.T.
(p 93)

• Mucous membranes,
• Lining of cavities that communicate with exterior
• Serous membranes,
• Lining of sealed, internal cavities
• Cutaneous membranes,
• Skin
• Synovial membranes,
• Joints

Know special names of serous membranes depending
on location Also know difference between
parietal and visceral
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Mucous vs. Serous Membrane
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Cutaneous Synovial Membranes
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Muscle Tissue Three types

• Skeletal

Cardiac
Smooth (not striated)

• The Four Primary Tissue Types
• Epithelial
• Connective
• Muscular
• Nervous

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Skeletal Muscle (chap 10)

• Voluntary
• Heavily striated
• Multinucleate
• periphery of the cell

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Cardiac Muscle (chap 18)

• Heart (Only)
• Involuntary
• Striated
• Intercalated disks
• Heavily branched
• Single central nucleus

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Smooth Muscle (chap 22)

• Involuntary
• Esp. digestive system
• No striations
• Very slow
• Single central nucleus

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Nervous Tissue (ch 12)

• Neurons
• Transmit electrical impulses
• Neuroglia
• Supportive cells of the nervous system

• The Four Primary Tissue Types
• Epithelial
• Connective
• Muscular
• Nervous

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Classic Motor Neuron
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Neuroglia covered in Nervous System (chapt. 13)

• Support
• Immune
• Transmission
• Nutrition
• Protection

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Muir Pass, Sierra Nevada