Download ap-lab-ex-6 - Anatomy and Physiology

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4-1 Four Types of Tissue
• Epithelial Tissue
– Covers exposed surfaces
– Lines internal passageways
– Forms glands
• Connective Tissue
–
–
–
–
Fills internal spaces
Supports other tissues
Transports materials
Stores energy
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4-1 Four Types of Tissue
• Muscle Tissue
– Specialized for contraction
– Skeletal muscle, heart muscle, and walls of hollow
organs
• Neural Tissue
– Carries electrical signals from one part of the body
to another
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4-2 Epithelial Tissue
• Epithelia
– Layers of cells covering internal or external
surfaces
• Glands
– Structures that produce secretions
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4-2 Epithelial Tissue
• Characteristics of Epithelia
– Cellularity (cell junctions)
– Polarity (apical and basal surfaces)
– Attachment (basement membrane or basal
lamina)
– Avascularity
– Regeneration
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Figure 6.1 Classification of epithelia.
Squamous
Apical surface
Cuboidal
Basal
surface
Simple
Apical surface
Basal
surface
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Stratified
Columnar
Figure 6.2 Formation of endocrine and exocrine glands from epithelial sheets.
Lumen of gland
Secretory cells
Exocrine gland
Epithelium
Area of
atrophied duct
Capillaries
Cord of
invaginating
epithelial cells
Secretory cells
Endocrine gland
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Figure 6.3a Epithelial tissues.
Simple squamous epithelium
Description: Single layer of flattened cells
with disc-shaped central nuclei and sparse
cytoplasm; the simplest of the epithelia.
Air sacs of
lung tissue
Nuclei
of squamous
epithelial
cells
Function: Allows materials to pass 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).
Photomicrograph: Simple squamous epithelium
forming part of the alveolar (air sac) walls (140).
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Figure 6.3b Epithelial tissues.
Simple cuboidal epithelium
Description: Single layer of cubelike
cells with large, spherical central
nuclei.
Simple
cuboidal
epithelial
cells
Function: Secretion and absorption.
Basement
membrane
Location: Kidney tubules; ducts and
secretory portions of small glands;
ovary surface.
Connective
tissue
Photomicrograph: Simple cuboidal epithelium
in kidney tubules (430).
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Figure 6.3c Epithelial tissues.
Simple columnar epithelium
Description: Single layer of tall cells with
round to oval nuclei; some cells bear cilia;
layer may contain mucus-secreting
unicellular glands (goblet cells).
Goblet cells
Mucus
secretion
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 rectum),
gallbladder, and excretory ducts of some
glands; ciliated variety lines small bronchi,
uterine tubes, and some regions of the
uterus.
Microvilli
(brush border)
Photomicrograph: Simple columnar epithelium containing
goblet cells from the small intestine (640).
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Figure 6.3d Epithelial tissues.
Pseudostratified columnar epithelium
Description: Single layer of cells of differing
heights, some not reaching the free surface;
nuclei seen at different levels; may contain
mucus-secreting goblet cells and bear cilia.
Mucus of
goblet cell
Cilia
Function: Secretes substances, particularly
mucus; propulsion of mucus by ciliary action.
Pseudostratified
epithelial
layer
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
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Basement
membrane
Photomicrograph: Pseudostratified ciliated
columnar epithelium lining the human trachea (530).
Figure 6.3e Epithelial tissues.
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.
Location: Nonkeratinized type forms the
moist linings of the esophagus, mouth, and
vagina; keratinized variety forms the
epidermis of the skin, a dry membrane.
Nuclei
Basement
membrane
Connective
tissue
Photomicrograph: Stratified squamous epithelium
lining the esophagus (280).
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Figure 6.3f Epithelial tissues.
Stratified cuboidal epithelium
Description: Generally two
layers of cubelike cells.
Basement
membrane
Cuboidal
epithelial
cells
Function: Protection
Location: Largest ducts of
sweat glands, mammary
glands, and salivary glands.
Duct
lumen
Photomicrograph: Stratified cuboidal
epithelium forming a salivary gland
duct (290).
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Figure 6.3g Epithelial tissues.
Stratified columnar epithelium
Description: Several cell layers;
basal cells usually cuboidal;
superficial cells elongated
and columnar.
Basement
membrane
Stratified
columnar
epithelium
Function: Protection; secretion.
Location: Rare in the body; small
amounts in male urethra and in
large ducts of some glands.
Urethra
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Connective
tissue
Photomicrograph: Stratified columnar epithelium
lining of the male urethra (290).
Figure 6.3h Epithelial tissues.
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
Photomicrograph: Transitional epithelium lining the urinary
bladder, relaxed state (365); 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.
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Connective
tissue
4-4 Connective Tissue
• Characteristics of Connective Tissue
1. Specialized cells
2. Solid extracellular protein fibers
3. Fluid extracellular ground substance
• The Extracellular Components of Connective
Tissue (Fibers and Ground Substance)
– Make up the matrix
• Majority of tissue volume
• Determines specialized function
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4-4 Connective Tissue
• Functions of Connective Tissue
–
–
–
–
Establishing a structural framework for the body
Transporting fluids and dissolved materials
Protecting delicate organs
Supporting, surrounding, and interconnecting other
types of tissue
– Storing energy reserves, especially in the form of
triglycerides
– Defending the body from invading
microorganisms
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4-4 Connective Tissue
• Classification of Connective Tissues
1. Connective tissue proper
• Connect and protect
2. Fluid connective tissues
• Transport
3. Supporting connective tissues
• Structural strength
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4-4 Connective Tissue
• Categories of Connective Tissue Proper
– Loose connective tissue
• More ground substance, fewer fibers
• For example, fat (adipose tissue)
– Dense connective tissue
• More fibers, less ground substance
• For example, tendons
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Figure 6.4 Areolar connective tissue: A prototype (model) connective tissue.
Cell types
Extracellular
matrix
Ground substance
Macrophage
Fibers
• Collagen fiber
• Elastic fiber
• Reticular fiber
Fibroblast
Lymphocyte
Fat cell
Mast cell
Neutrophil
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Capillary
Figure 6.5a Connective tissues.
Embryonic connective tissue: Mesenchyme
Description: Embryonic connective
tissue; gel-like ground substance
containing fibers; star-shaped
mesenchymal cells.
Fibers
Function: Gives rise to all other
connective tissue types.
Location: Primarily in embryo.
Ground
substance
Mesenchymal
cell
Photomicrograph: Mesenchymal tissue, an embryonic
connective tissue (627); the clear-appearing background is
the fluid ground substance of the matrix; notice the fine,
sparse fibers.)
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Figure 6.5b Connective tissues.
Connective tissue proper: loose connective tissue, areolar
Description: Gel-like matrix with all
three fiber types; cells: fibroblasts,
macrophages, mast cells, and some
white blood cells.
Collagen
fibers
Function: Wraps and cushions organs;
its macrophages phagocytize bacteria;
plays important role in inflammation;
holds and conveys tissue fluid.
Fibroblast
nuclei
Location: Widely distributed under
epithelia of body, e.g., forms lamina
propria of mucous membranes;
packages organs; surrounds capillaries.
Elastic
fibers
Epithelium
Lamina
propria
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Photomicrograph: Areolar connective tissue, a soft packaging
tissue of the body (365).
Figure 6.5c Connective tissues.
Connective tissue proper: loose connective tissue, adipose
Description: Matrix as in areolar,
but very sparse; closely packed
adipocytes, or fat cells, have
nucleus pushed to the side by
large fat droplet.
Function: Provides reserve fuel;
insulates against heat loss;
supports and protects organs.
Vacuole
containing
fat droplet
Location: Under skin; around
kidneys and eyeballs; within
abdomen; in breasts.
Nuclei of
fat cells
Photomicrograph: Adipose tissue from the
subcutaneous layer under the skin (110).
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Figure 6.5d Connective tissues.
Connective tissue proper: loose connective tissue, reticular
Description: Network of reticular
fibers in a typical loose ground
substance; reticular cells lie on
the network.
Function: Fibers form a soft
internal skeleton (stroma) that
supports other cell types,
including white blood cells, mast
cells, and macrophages.
White
blood cell
(lymphocyte)
Location: Lymphoid organs
(lymph nodes, bone marrow,
and spleen).
Reticular
fibers
Spleen
Photomicrograph: Dark-staining network of
reticular connective tissue fibers forming the
internal skeleton of the spleen (350).
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Figure 6.5e Connective tissues.
Connective tissue proper: dense connective tissue, dense regular
Description: Primarily parallel
collagen fibers; a few elastic fibers;
major cell type is the fibroblast.
Function: Attaches muscles to bones
or to muscles; attaches bones to bones;
withstands great tensile stress when
pulling force is applied in one direction.
Collagen
fibers
Location: Tendons, most
ligaments, aponeuroses.
Nuclei of
fibroblasts
Shoulder
joint
Ligament
Photomicrograph: Dense regular connective tissue
from a tendon (590).
Tendon
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Figure 6.5f Connective tissues.
Connective tissue proper: dense connective tissue, elastic
Description: Dense regular connective
tissue containing a high proportion of
elastic fibers.
Function: Allows recoil of tissue
following stretching; maintains
pulsatile flow of blood through
arteries; aids passive recoil of lungs
following inspiration.
Location: Walls of large arteries;
within certain ligaments associated
with the vertebral column; within the
walls of the bronchial tubes.
Elastic
fibers
Aorta
Heart
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Photomicrograph: Elastic connective tissue in the
wall of the aorta (250).
Figure 6.5g Connective tissues.
Connective tissue proper: dense connective tissue, dense irregular
Description: Primarily irregularly
arranged collagen fibers; some elastic
fibers; major cell type is the fibroblast.
Nuclei of
fibroblasts
Function: Able to withstand tension
exerted in many directions; provides
structural strength.
Location: Fibrous capsules of organs
and of joints; dermis of the skin;
submucosa of digestive tract.
Collagen
fibers
Fibrous
joint
capsule
Photomicrograph: Dense irregular connective
tissue from the dermis of the skin (210).
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Figure 6.5h Connective tissues.
Cartilage: hyaline
Description: Amorphous but firm matrix;
collagen fibers form an imperceptible
network; chondroblasts produce the
matrix and when mature (chondrocytes)
lie in lacunae.
Chondrocyte
in lacuna
Function: Supports and reinforces;
serves as resilient cushion; 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.
Costal
cartilages
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Matrix
Photomicrograph: Hyaline cartilage from a costal
cartilage of a rib (470).
Figure 6.5i Connective tissues.
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 (auricle); epiglottis.
Matrix
Photomicrograph: Elastic cartilage from the
human ear auricle; forms the flexible skeleton
of the ear (510).
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Figure 6.5j Connective tissues.
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 (160). Special staining produced the blue color seen.
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Figure 6.5k Connective tissues.
Bones (osseous tissue)
Description: Hard, calcified matrix
containing many collagen fibers;
osteocytes lie in lacunae. Very
well vascularized.
Function: Bone supports and
protects (by enclosing); provides
levers for the muscles to act on;
stores calcium and other minerals
and fat; marrow inside bones is the
site for blood cell formation
(hematopoiesis).
Central
canal
Lacunae
Lamella
Location: Bones
Photomicrograph: Cross-sectional view of bone (175).
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Figure 6.5l Connective tissues.
Blood
Description: Red and white
blood cells in a fluid matrix
(plasma).
Function: Transport of
respiratory gases, nutrients,
wastes, and other substances.
Location: Contained within
blood vessels.
Plasma
Neutrophil
Red blood
cells
Lymphocyte
Photomicrograph: Smear of human blood (1000);
two white blood cells (neutrophil and lymphocyte) are
seen surrounded by red blood cells.
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4-9 Neural Tissue
• Neural Tissue
– Also called nervous or nerve tissue
• Specialized for conducting electrical impulses
• Rapidly senses internal or external environment
• Processes information and controls responses
– Neural tissue is concentrated in the central nervous
system
• Brain
• Spinal cord
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4-9 Neural Tissue
• Two Types of Neural Cells
1. Neurons
• Nerve cells
• Perform electrical communication
2. Neuroglia
• Supporting cells
• Repair and supply nutrients to neurons
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4-9 Neural Tissue
• Cell Parts of a Neuron
– Cell body
• Contains the nucleus and nucleolus
– Dendrites
• Short branches extending from the cell body
• Receive incoming signals
– Axon (nerve fiber)
• Long, thin extension of the cell body
• Carries outgoing electrical signals to their destination
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Figure 6.6 Nervous tissue.
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 nonexcitable supporting cells.
Neuron processes
Nuclei of
supporting
cells
Cell body
Axon Dendrites
Cell body
of a neuron
Function: Neurons transmit electrical
signals from sensory receptors and to
effectors (muscles and glands); supporting
cells support and protect neurons.
Neuron
processes
Location: Brain, spinal
cord, and nerves.
Photomicrograph: Neurons (370)
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4-8 Muscle Tissue
• Muscle Tissue
– Specialized for contraction
– Produces all body movement
– Three types of muscle tissue
1.
Skeletal muscle tissue
– Large body muscles responsible for movement
2. Cardiac muscle tissue
– Found only in the heart
3.
Smooth muscle tissue
– Found in walls of hollow, contracting organs (blood vessels;
urinary bladder; respiratory, digestive, and reproductive tracts)
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4-8 Muscle Tissue
• Classification of Muscle Cells
–
–
–
–
–
Striated (muscle cells with a banded appearance)
Nonstriated (not banded; smooth)
Muscle cells can have a single nucleus
Muscle cells can be multinucleate
Muscle cells can be controlled voluntarily
(consciously)
– Muscle cells can be controlled involuntarily
(automatically)
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4-8 Muscle Tissue
• Skeletal Muscle Cells
–
–
–
–
Long and thin
Usually called muscle fibers
Do not divide
New fibers are produced by stem cells
(myosatellite cells)
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Figure 6.7a Muscle tissues.
Skeletal muscle
Description: Long, cylindrical,
multinucleate cells; obvious
striations.
Part of
muscle
fiber (cell)
Function: Voluntary movement;
locomotion; manipulation of the
environment; facial expression;
voluntary control.
Nuclei
Location: In skeletal muscles
attached to bones or occasionally
to skin.
Striations
Photomicrograph: Skeletal muscle (approx. 550).
Notice the obvious banding pattern and the
fact that these large cells are multinucleate.
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Figure 6.7b Muscle tissues.
Cardiac muscle
Description: Branching, striated,
generally uninucleate cells that
interdigitate at specialized junctions
called intercalated discs.
Nucleus
Intercalated
discs
Function: As it contracts, it
propels blood into the circulation;
involuntary control.
Striations
Location: The walls of the heart.
Photomicrograph: Cardiac muscle (775);
notice the striations, branching of cells, and
the intercalated discs.
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Figure 6.7c Muscle tissues.
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
Nucleus
Photomicrograph: Smooth muscle cells (265).
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Review Figure 6.1 (1 of 2)
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Review Figure 6.1 (2 of 2)
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Review Figure 6.1a
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Review Figure 6.1b
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Review Figure 6.1c
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Review Figure 6.1d
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Review Figure 6.1e
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Review Figure 6.1f
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Review Figure 6.1g
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Review Figure 6.1h
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Review Figure 6.1i
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Review Figure 6.1j
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Review Figure 6.1k
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Review Figure 6.1l
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