Download tissues - Wando High School

TISSUES
TISSUES
 Groups of cells similar in structure and function
 2 or more different tissue types must be present to be
classified as an organ.
 Histology is the study of tissues
 4 types total
TISSUES
 Types of tissues

Epithelial tissue

Connective tissue

Muscle tissue

Nerve tissue
EPITHELIAL TISSUES
 FUNCTIONS:
 PROTECTION
 ABSORPTION
 FILTRATION
 SECRETION
They also:
-line and cover every external and internal surface of the body
-provide lubrication
-contains all three junctions(gap, tight, and desmosome)
EPITHELIAL TISSUES
 Characteristics
 Avascular: does not contain a blood supply
Die and replace themselves quickly
 Make thin layers

•
•
•
Innervated: has a nerve supply
Always supported by connective tissue
Always has 2 surfaces
•
•
Apical: open or free side
Basal: attached to connective tissue
Shape Classification
 Squamous: flattened, scale-like cells
irregular borders
many tight junctions
 Cuboidal: square or rounded in shape
 Commonly line lumens(space or a duct)
 Columnar: rectangular or column shape cells
 Usually simple
 Produce lots of fluid (goblet cells)
 Line the digestive tract
Layers
 Simple= one layer of cells
 Stratified= 2 or more layers of cells
 Pseudostratified= false layers- only one layer present
 **stratified squamous= most common epithelial
tissue
Function: Allows passage of
materials by diffusion and filtration
in sites where protection is not
important; secretes lubricating
substances in serosae.
Location: Kidney glomeruli; air sacs
of lungs; lining of heart, blood
vessels, and lymphatic vessels; lining
of ventral body cavity (serosae).
Function: Secretion and
absorption.
Location: Kidney tubules;
ducts and secretory portions
of small glands; ovary surface.
(c) Simple columnar epithelium
Description: Single layer of tall cells
with round to oval nuclei; some cells
bear cilia; layer may contain mucussecreting unicellular glands (goblet cells).
Simple
columnar
epithelial
cell
Function: Absorption; secretion of
mucus, enzymes, and other substances;
ciliated type propels mucus (or
reproductive cells) by ciliary action.
Location: Nonciliated type lines most of
the digestive tract (stomach to anal canal),
gallbladder, and excretory ducts of some
glands; ciliated variety lines small
bronchi, uterine tubes, and some regions
of the uterus.
Basement
membrane
Photomicrograph: Simple columnar epithelium
of the stomach mucosa (860X).
Figure 4.3c
(d) Pseudostratified columnar epithelium
Description: Single layer of cells of
differing heights, some not reaching
the free surface; nuclei seen at
different levels; may contain mucussecreting cells and bear cilia.
Cilia
Mucus of
mucous cell
Pseudostratified
epithelial
layer
Function: Secretion, particularly of
mucus; propulsion of mucus by
ciliary action.
Location: Nonciliated type in male’s
sperm-carrying ducts and ducts of
large glands; ciliated variety lines
the trachea, most of the upper
respiratory tract.
Trachea
Photomicrograph: Pseudostratified ciliated
columnar epithelium lining the human trachea (570x).
Basement
membrane
Figure 4.3d
(e) Stratified squamous epithelium
Description: Thick membrane
composed of several cell layers;
basal cells are cuboidal or columnar
and metabolically active; surface
cells are flattened (squamous); in the
keratinized type, the surface cells are
full of keratin and dead; basal cells
are active in mitosis and produce the
cells of the more superficial layers.
Stratified
squamous
epithelium
Function: Protects underlying
tissues in areas subjected to abrasion.
Nuclei
Location: Nonkeratinized type forms
the moist linings of the esophagus,
mouth, and vagina; keratinized variety
forms the epidermis of the skin, a dry
membrane.
Basement
membrane
Connective
tissue
Photomicrograph: Stratified squamous epithelium
lining the esophagus (285x).
Figure 4.3e
(f) Transitional epithelium
Description: Resembles both
stratified squamous and stratified
cuboidal; basal cells cuboidal or
columnar; surface cells dome
shaped or squamouslike, depending
on degree of organ stretch.
Transitional
epithelium
Function: Stretches readily and
permits distension of urinary organ
by contained urine.
Location: Lines the ureters, urinary
bladder, and part of the urethra.
Basement
membrane
Connective
tissue
Photomicrograph: Transitional epithelium lining the urinary
bladder, relaxed state (360X); note the bulbous, or rounded,
appearance of the cells at the surface; these cells flatten and
become elongated when the bladder is filled with urine.
Figure 4.3f
Glandular and Epithelial Tissue
 Duct glandular: glands that have ducts
 Exocrine glands
 Very numerous
 Sweat glands, salivary glands, oil glands, tear glands

Merocrine glands: glands that make secretions, dump them into a
lumen, and muscles squeeze the product out- sweat glands.
 Have a low cellular death

Holocrine glands: cells lyse to secrete their products- oil glands
 High cellular death
 2. Ductless glandular: glands that do not have ducts.
 Endocrine gland
 Pituitary, thymus, thyroid, adrenal
 Uses the blood stream to deliver its products
 Very few glands and their effects will last longer
Connective Tissue
 Most abundant and widely distributed tissue
 Functions:
 1. bind and support
 2. Protection
 3. insulation
 4. transportation
Connective tissue
 Classes




Connective tissue proper
Cartilage
Bone
Blood
In order to be classified as connective tissue, you must
have the following:
-common origin(arise from mesenchyme)
-vary in vascularity
-extracellular matrix: non-living area surrounding each
cell
Table 4.1
Connective Tissue: Structural Requirements
 Ground substance: extra cellular matrix
 Fibers: strands of protein that provide support
 Cells: living portion of connective tissue
 -fibroblast: makes fibers
 -chondroblast: makes cartilage
 -ostoeblast: makes bone cells
 -hemocytoblast: makes blood cells

Hemotopoietic stem cell
A. Connective Tissue Proper
 1. Loose areolar tissue: most common
 Supports and binds tissues
 Retains/holds body fluids
 Defends against infection
 Helps store nutrients
2. Loose Adipose tissue: fat (Connective cont.)
 Nutrient storage
 Insulation
 A. Brown fat: warms body,
thermoregulates, insulates,
nutrient, metabolism
 B. white fat: stores excess
material and causes body to appear heavy
3. Dense Regular Tissue (Connective cont.)
 Ligaments: hold /attach bones to bones
 Tendon: hold/attach muscles to bones
B. Cartilage Connective Tissue
 Avascular and not innervated and gets its nutrients
through diffusion of other tissues.

1. hyaline: gristle
Most abundant
 Found at the ends of all long bones
 Keeps bones from crushing
2. Elastic:
-similar to hyaline, but more elastic fibers
-maintains shape with flexibility
-external ear
3. Fibrocartilage
-absorbs compression shock
-interval disks

(g) Cartilage: hyaline
Description: Amorphous but firm
matrix; collagen fibers form an
imperceptible network; chondroblasts
produce the matrix and when mature
(chondrocytes) lie in lacunae.
Function: Supports and reinforces;
has resilient cushioning properties;
resists compressive stress.
Location: Forms most of the
embryonic skeleton; covers the ends
of long bones in joint cavities; forms
costal cartilages of the ribs; cartilages
of the nose, trachea, and larynx.
Chondrocyte
in lacuna
Matrix
Costal
cartilages
Photomicrograph: Hyaline cartilage from the
trachea (750x).
Figure 4.8g
(h) Cartilage: elastic
Description: Similar to hyaline
cartilage, but more elastic fibers
in matrix.
Function: Maintains the shape
of a structure while allowing
great flexibility.
Chondrocyte
in lacuna
Location: Supports the external
ear (pinna); epiglottis.
Matrix
Photomicrograph: Elastic cartilage from
the human ear pinna; forms the flexible
skeleton of the ear (800x).
Figure 4.8h
(i) Cartilage: fibrocartilage
Description: Matrix similar to
but less firm than that in hyaline
cartilage; thick collagen fibers
predominate.
Function: Tensile strength
with the ability to absorb
compressive shock.
Location: Intervertebral discs;
pubic symphysis; discs of knee
joint.
Chondrocytes
in lacunae
Intervertebral
discs
Collagen
fiber
Photomicrograph: Fibrocartilage of an
intervertebral disc (125x). Special staining
produced the blue color seen.
Figure 4.8i
C. Bone (Connective Tissue)
 Provides the skeletal system
 1. compact bone-dense bone
that forms the exterior margins
of the bone
 2. Spongy bone- honeycomb
webbing of bone at the ends
of long bone that give strength
without weight.
D. Blood ( Connective tissue)
 Blood: most fluid of all connective tissues
 Formed elements: RBC, WBC, platelets
 Plasma: extracellular matrix: water and dissolved compounds
Muscle Tissue
 Functions:
 1. support
 2. protection
 3. shapes body
 4. produces movement
 Characteristics:
 1. Highly cellular
 2. highly vascular
 3. innervated
 4. contain myofilaments
Muscle Tissue: Three Types
 1. Skeletal: muscles attached to bones
 Cells: long, cylindrical, and multinucleated
 Visible striations
 Voluntarily controlled
(a) Skeletal muscle
Description: Long, cylindrical,
multinucleate cells; obvious
striations.
Striations
Function: Voluntary movement;
locomotion; manipulation of the
environment; facial expression;
voluntary control.
Location: In skeletal muscles
attached to bones or
occasionally to skin.
Nuclei
Part of
muscle
fiber (cell)
Photomicrograph: Skeletal muscle (approx. 460x).
Notice the obvious banding pattern and the
fact that these large cells are multinucleate.
Figure 4.10a
Muscle Tissue : Types
 2. Cardiac: muscle of the heart only
 Cells: short, branching cells, and uninucleated
 Visible striations
 Intercalated discs: areas where cardiac cells merge.
 Involuntarily controlled
(b) Cardiac muscle
Description: Branching,
striated, generally uninucleate
cells that interdigitate at
specialized junctions
(intercalated discs).
Striations
Intercalated
discs
Function: As it contracts, it
propels blood into the
circulation; involuntary control.
Location: The walls of the
heart.
Nucleus
Photomicrograph: Cardiac muscle (500X);
notice the striations, branching of cells, and
the intercalated discs.
Figure 4.10b
Muscle Tissue: Types
 Smooth: muscles of hollow organs and vessels
 Cells, long, spindle shaped, and uninucleated (central)
 No visible striations
 Involuntarily controlled
(c) Smooth muscle
Description: Spindle-shaped
cells with central nuclei; no
striations; cells arranged
closely to form sheets.
Function: Propels substances
or objects (foodstuffs, urine,
a baby) along internal passageways; involuntary control.
Location: Mostly in the walls
of hollow organs.
Smooth
muscle
cell
Nuclei
Photomicrograph: Sheet of smooth muscle (200x).
Figure 4.10c
Nervous Tissue
 Functions:
 produces/sends electrical impluses
 Control over all body systems/functions
 2Types:
 1. neuron: highly specialized cell tht can propagate an impluse
by moving ions across its membrane
Longevity
 Long in length
 characteristics: dendrites, axons, neurotransmitters, cell body,
axon terminals


2. supporting cells: specialized cells desighned to carry out
functions for the nervous system/neurons specifically
Nervous tissue
Description: Neurons are
branching cells; cell processes
that may be quite long extend from
the nucleus-containing cell body;
also contributing to nervous tissue
are nonirritable supporting cells
(not illustrated).
Nuclei of
supporting
cells
Neuron processes Cell body
Axon
Dendrites
Cell body
of a neuron
Function: Transmit electrical
signals from sensory receptors
and to effectors (muscles and
glands) which control their activity.
Location: Brain, spinal
cord, and nerves.
Neuron
processes
Photomicrograph: Neurons (350x)
Figure 4.9