ACS-1 - Tissue Level of Organization.ppt

Copyright © 2010 Pearson Education, Inc.
Tissue Level of
Organization

16.1 Tissues
Levels of organization:
 Cells Smallest
 Tissues
 Organs
 Organ Systems
 Organisms Largest
Tissues = group of similar cell types that
perform a common function.

16.1 Tissues
Tissues = group of similar cell types that
perform a common function.
Four basic types of tissue:
1. Epithelial
2. Connective
3. Muscle
4. Nervous

16.1 Tissues - Epithelial Tissue
Epithelium is tightly
packed sheets of
cells
 cover organs and
outer surfaces
 line insides of
hollow organs,
vessels, and body
cavities.
Figure 16.1
(a) Examples of organs lined with epithelial
tissue:
(b) Epithelial cells in skin
Heart and blood vessels
Respiratory tract
Digestive tract
Urogenital tract
Epidermis
(c) Epithelial cells lining
the small intestine

16.1 Tissues - Epithelial Tissue
Epithelia are polar
 anchored on one surface, but free on another
 The free side is typically exposed to the
environment or body fluids
 Can be single layer or many
layers thick
 Function in protection,
secretion, and absorption
 Epithelial cells are
continuously sloughing off and
are replaced by cell division

What are epithelial cells?
 Epithelial tissue is made up of epithelial
cells. The cells can be different shapes
and can be arranged in a single layer or
multiple layers depending on where they
are in your body and what kind of functions
they have.

What are the different types of epithelial
cells?

 Squamous epithelium: Squamous
epithelial cells are flat and sheet-like in
appearance.

LOCATION
In the lining of the
blood vessels like the
arteries, veins, and
capillaries.

Function/s
 Simple squamous epithelial cells form a
membrane that allows selective diffusion
of materials to pass through

 Cuboidal epithelium: Cuboidal epithelial
cells are cube-like in appearance, meaning
they have equal width, height and depth.

LOCATION
 found on the surface of ovaries, the lining
of nephrons, the walls of the renal tubules,
parts of the eye and thyroid, and in
salivary glands

Function/s
 The main function of the cuboidal cell
epithelium is to help in absorption,
excretion, and secretion

 Columnar epithelium: Columnar
epithelial cells are column-like in
appearance, meaning they are taller than
they are wide.

Location
The columnar epithelium is found in those
parts which are responsible for absorption
and secretion, such as it forms the lining of
the intestine, stomach, and colon, forming
mucous membrane. The columnar
epithelium also forms a lining in the gall
bladder and oviducts.

Function/s
 Secretion, excretion, and absorption are
the primary functions of the simple
columnar epithelium.

Epithelial cells based on specialized
functions
 Transitional epithelium: A transitional
epithelium (also known as urothelium) is
made up of several layers of cells that
become flattened when stretched. It lines
most of your urinary tract and allows your
bladder to expand.

 Glandular epithelium: This type of
epithelium is specialized to produce and
secrete (release) substances. It’s found in
your glands, which are specialized organs
that can make, store and/or release
substances such as hormones, proteins
and water.

 Olfactory epithelium: The olfactory
epithelium, located within your nasal
cavity, contains olfactory receptor cells,
which have specialized cilia extensions.
The cilia trap odor molecules you breathe
in as they pass across the epithelial
surface. Information about the molecules
is then transmitted from the receptors to
the olfactory bulb in your brain, where your
brain then interprets the smell.

What does the epithelium do?
 Epithelial tissue has several important
functions that are essential to life. Since
epithelial cells are found throughout your
body, their function and purpose change
based on their location.

 Protection: Epithelial tissue protects
several aspects of your body. For
example, your skin is made up of epithelial
tissue and protects the tissues deeper in
your body, such as blood vessels, muscle
and internal organs. The cilia on the
epithelial cells that line your intestines
protect the rest of your body from intestinal
bacteria.

 Secretion: Epithelial tissue in your glands
(glandular epithelium) can secrete
(release) enzymes, hormones and fluids.
 Absorption: The epithelial lining of your
internal organs, such as your liver and
lungs, can allow the absorption of certain
substances.
 For example, the internal epithelial lining of
your intestines absorbs nutrients from the
food you eat.

 Excretion: Excretion is the removal of
waste from your body. The epithelial tissue
in your kidneys excrete waste, and the
epithelial tissue in your sweat glands
excrete sweat.

 Filtration: The epithelium of your
respiratory tract filters out dirt and particles
and cleans the air that you breathe in.
Epithelial tissue in your kidneys filters your
blood.

 Diffusion: In biology, diffusion is the
passive movement of molecules or
particles from regions of higher
concentrations to regions of lower
concentration. Simple squamous epithelial
cells form a membrane that allows
selective diffusion of materials to pass
through. Diffusion helps with filtration,
absorption and secretion functions.

 Sensory reception: Sensory nerve
endings that are embedded in epithelial
tissue allow your body to receive outside
sensory stimuli. As an example, the
stereocilia on the surface of the epithelial
tissue in your ear are essential for hearing
and balance. In addition, your taste buds
are embedded in the stratified squamous
epithelium of your tongue.

TYPES OF TISSUES

16.1 Tissues - Connective Tissue
Connective Tissue
 Loosely organized and composed of cells
embedded in a matrix
 Cells
 Examples include: Blood cells, adipocytes,
fibroblasts, chondrocytes, osteocytes
 Matrix is composed of two things
1. Ground substance
 May be liquid, gel-like, rubbery or solid
2. Fibers
 Collagen, elastin, reticular fibers

Connective Tissue
 Usually binds organs or tissues to one another
 Six different types:
1. Loose connective tissue
2. Adipose tissue
3. Blood
4. Fibrous connective tissue
5. Cartilage
6. Bone

Copyright © 2010 Pearson Education, Inc. Figure 16.2a
 Most widespread tissue in
animal body
 Matrix composed of
collagen and elastin fibers
 Cells are fibroblasts and
adipocytes
 It is called “loose” because
fibers are loosely woven
together
 Binds epithelia to tissues,
pads skin, and holds organs
in place
Loose Connective Tissue

Adipose Tissue
 AKA Fat
 Primarily adipocytes;
small amount of matrix
 Functions
 Used for storage of
energy (fat)
 Insulation
 Padding for organs
Figure 16.2b

Blood
 Cellular component
 red blood cells, white
blood cells and
platelets
 Matrix is the plasma
 Functions include
carrying oxygen and
nutrients; fighting
infection
Figure 16.2c
Red
blood cell
Platelet
White
blood cell
Plasma
(c) Blood

Fibrous Connective
Tissue
 Forms tendons and
ligaments
 Matrix is collagen
fibers running in
parallel
 Cells are fibroblasts
Figure 16.2d
Fibroblast
cell
Parallel
collagen
fibers
(d) Fibrous connective tissue (tendon)

Copyright © 2010 Pearson Education, Inc. Figure 16.2e
Matrix
Matrix
Chondro-
cytes
(e) Cartilage
(at the end of a bone)
Cartilage
 Cells are chondrocytes
 Cells secrete rubbery
matrix, collagen and
elastin
 Cartilage cushions joints,
forms support for ears
and nose
 Not vascularized, so takes
a long time to heal if
injured

Copyright © 2010 Pearson Education, Inc. Figure 16.2f
Matrix
Osteocytes
Central
canal
(f) Bone
Bone
 Rigid connective tissue
 Cells are osteocytes
 Cells secrete matrix of
collagen fibers and
calcium salts
 Bone marrow produces
blood cells
 Body can make use of
calcium from bones if
dietary levels are too low

16.1 Tissues - Muscle Tissue
Muscle is contractile tissue
 Long, thin cylindrical cells called muscle
fibers
 Two proteins – actin and myosin – interact
to cause contraction of muscle fibers
Three types of muscle:
1. Skeletal
2. Cardiac
3. Smooth

Skeletal Muscle
 Usually attached to bone
 Produces all voluntary movements
 Striated – due to overlap of actin & myosin
 Long, thin, cylindrical shape
Figure 16.3a
Muscle fiber Nucleus
(a) Skeletal muscle (biceps)

Copyright © 2010 Pearson Education, Inc. Figure 16.3b
(b) Cardiac muscle (heart)
Cardiac Muscle
 Only found in
heart tissue
 Striated
 Involuntary,
undergoes
rhythmic
contractions to produce heartbeat
 Branched, interlocking cells propagate signal
to contract almost simultaneously

Copyright © 2010 Pearson Education, Inc. Figure 16.3c
(c) Smooth muscle (intestine)
Smooth Muscle
 Not striated
 Spindle-shaped cells
 Musculature of
organs, blood
vessels, digestive
tract
 Involuntary
 Contracts more slowly and for longer than
skeletal muscle

16.1 Tissues - Nervous Tissue
Nervous Tissue
 Neurons conduct electrical signals
 Primary cells of the brain and spinal cord
 Main function of neurons is to:
 Sense stimuli
 Process stimuli
 Transmit signals
 Most cells of nervous system do not
undergo cell division

16.1 Tissues - Tissue Donation
Brain death and Tissue Donation
 Injuries from motor vehicle accidents, burst
blood vessels, and drowning are common
causes of brain death
 Once dead, brain cells cannot recover
 Other tissues can be harvested to help others
 > One person’s tissues can improve the
lives of as many as 50 people.

ACS-1 - Tissue Level of Organization.ppt

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