Download bio 12 8.1 TISSUES

UNIT B: Human Body Systems
Chapter 8: Human Organization:
Section 8.1
Chapter 9: Digestive System
Chapter 10: Circulatory System and
Lymphatic System
Chapter 11: Respiratory System
Chapter 12: Nervous System
Chapter 13: Urinary System
Chapter 14: Reproductive System
UNIT B Chapter 8: Human Organization
Chapter 8: Human Organization
In this chapter, you will learn
about how the systems in our
bodies are connected and
work together to maintain a
relatively constant internal
environment.
What situations might disrupt the
internal state of the body?
How can alleviating stress improve
your health and quality of life?
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UNIT B Chapter 8: Human Organization
Section 8.1
8.1 Types of Tissues
Tissues are composed of similarly specialized cells that
perform a common function in the body.
There are four major types of tissues in the human body:
• Epithelial tissue: covers body surfaces, lines body cavities
• Connective tissue: binds and supports body parts
• Muscular tissue: moves the body and its parts
• Nervous tissue: receives stimuli, processes information,
conducts nerve impulses
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UNIT B Chapter 8: Human Organization
Section 8.1
Epithelial Tissue
Epithelial tissue (epithelium) consists of tightly packed cells that
form a continuous layer.
Functions of epithelial tissue:
• Covers surfaces and lines body cavities
• External surface: protects the body from injury, drying out, and
invasion by microbes
• Internal surface: secretes mucus along the digestive tract, sweeps
up impurities from the lungs by means of cilia, absorbs
molecules from kidney tubules and the intestine through
microvilli
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UNIT B Chapter 8: Human Organization
Section 8.1
Structure of epithelial tissue:
• A basement membrane usually joins an epithelium to
underlying connective tissue
• Epithelial tissue is classified according to the shape of the
cell it is composed of and the number of layers in the tissue.
o Classification based on shape:
− Squamous epithelium: flattened cells
− Cuboidal epithelium: cube-shaped cells
− Columnar epithelium: rectangular-shaped cells
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UNIT B Chapter 8: Human Organization
Section 8.1
o Classification based on number of layers in the tissue:
− Simple epithelium: single layer of cells
− Stratified epithelium: multiple layers of cells
− Pseudostratified epithelium: appears to be layered,
but true layers do not exist because each cell touches
the basement membrane
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UNIT B Chapter 8: Human Organization
Figure 8.1 Epithelial tissue. Certain
types of epithelial tissue—squamous,
cuboidal, and columnar—are named
for the shapes of their cells. They all
have a protective function in addition
to other specific functions.
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Section 8.1
UNIT B Chapter 8: Human Organization
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Section 8.1
UNIT B Chapter 8: Human Organization
Section 8.1
Epithelium as glands
• When an epithelium secretes a product, it is said to be
glandular.
• A gland can be a single epithelial cell or can contain many
cells.
o Glands that secrete their product into ducts are called
exocrine glands (e.g., salivary glands)
o Glands that secrete their product into the bloodstream
are called endocrine glands (e.g., thyroid gland)
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UNIT B Chapter 8: Human Organization
Connective Tissue
Connective tissues have a wide variety of functions.
Functions of connective tissue:
• Binds organs together
• Provides support and protection
• Fills spaces
• Produces blood cells
• Stores fat
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Section 8.1
UNIT B Chapter 8: Human Organization
Section 8.1
Structure of connective tissues:
• Connective tissue cells are widely separated by a solid,
jellylike, or fluid matrix.
o A nonfluid matrix may contain three types of fibres:
− White collagen fibres: contain collagen to give
flexibility and strength
− Reticular fibres: thin collagen fibres that form
supporting networks
− Yellow elastic fibres: contain elastin to give elasticity
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UNIT B Chapter 8: Human Organization
Blood
Blood is a liquid connective tissue.
Functions of blood:
• Transports nutrients and oxygen to tissue fluid
• Removes carbon dioxide and other wastes
• Distributes heat
• Involved in fluid, ion, and pH balance
• Protects from disease
• Prevents fluid loss through clotting
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Section 8.1
UNIT B Chapter 8: Human Organization
Section 8.1
Composition of blood:
• Plasma: 55%
o inorganic and organic
substances in water
• Formed elements: 45%
o Red blood cells, white
blood cells, blood platelets
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Figure 8.2 Blood, a liquid connective
tissue. a. Blood is often classified as
connective tissue because the cells are
separated by a matrix—plasma. The
formed elements consist of several
types of cells.
UNIT B Chapter 8: Human Organization
Section 8.1
Figure 8.2 Blood, a liquid connective
tissue. a. Blood is often classified as
connective tissue because the cells are
separated by a matrix—plasma. The
formed elements consist of several types of
cells. b. A drawing of the components of
blood: plasma, red blood cells, white blood
cells, and platelets (which are actually
fragments of a larger cell).
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UNIT B Chapter 8: Human Organization
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Section 8.1
UNIT B Chapter 8: Human Organization
Formed elements of blood:
• Red blood cells (erythrocytes)
o Small, biconcave, disk-shaped
cells without nuclei
o Contain the pigment
hemoglobin, which makes the
cells and blood red
o Hemoglobin associates with
oxygen, allowing red blood
cells to transport oxygen
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Section 8.1
UNIT B Chapter 8: Human Organization
• White blood cells (leukocytes)
o Larger cells that have a
nucleus
o Can fight infection through
phagocytosis or through
adaptive immunity
• Platelets (thrombocytes)
o Fragments of large cells
present only in bone marrow
o Help form plugs to seal
damaged blood vessels
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Section 8.1
UNIT B Chapter 8: Human Organization
Section 8.1
Muscular Tissue
Muscular tissue is composed of cells called muscle fibres,
which function in voluntary and involuntary movement.
There are three types of muscle tissue:
• Skeletal muscle
• Smooth muscle
• Cardiac muscle
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UNIT B Chapter 8: Human Organization
Skeletal muscle
• Attached by tendons to the
bones of the skeleton
• Has striated cells with
multiple nuclei
• Functions in voluntary
movement
Figure 8.3 Muscular tissue. a. Skeletal
muscle is voluntary and striated.
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Section 8.1
UNIT B Chapter 8: Human Organization
Smooth muscle
• Has spindle-shaped cells with
a single nucleus
• Cells do not have striations
• Found in blood vessels and
walls of viscera
• Functions in movements that
are involuntary
Figure 8.3 Muscular tissue. b. Smooth
muscle is involuntary and nonstriated.
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Section 8.1
UNIT B Chapter 8: Human Organization
Cardiac muscle
• Found only in walls of the
heart
• Has striated cells with a single
nucleus in each cell
• Involved in movements that
are involuntary
Figure 8.3 Muscular tissue. c. Cardiac
muscle is involuntary and striated. Cardiac
muscle cells branch and fit together at
intercalated disks.
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Section 8.1
UNIT B Chapter 8: Human Organization
Section 8.1
Nervous Tissue
Nervous tissue, which contains nerve cells called neurons, is
present in the brain and spinal cord.
Functions of nervous tissue
• Sensory input: nerves conduct impulses from sensory
receptors to the spinal cord and brain
• Integration of data
• Motor output: nerves conduct nerve impulses away from
the spinal cord and brain to the muscles and glands
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UNIT B Chapter 8: Human Organization
Section 8.1
Nervous Tissue
Structure of nervous tissue
• Nervous tissue contains neurons
o A neuron is a specialized cell that has three parts.
− Cell body: contains the nucleus and a majority of the
cytoplasm
− Dendrites: conduct signals toward the cell body
− Axon: conducts nerve impulses away from the cell
body; bundles of axons bound by connective tissue
are called nerves
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UNIT B Chapter 8: Human Organization
Section 8.1
Check Your Progress
1. List five types of epithelium, and identify a location
where each could be found in the human body.
2. Describe the structure and function of skeletal, smooth,
and cardiac muscle.
3. Name the three parts of a neuron, and define nerve
fibre.
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UNIT B Chapter 8: Human Organization
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Section 8.1