Transcript Marieb_ch3c

Body Tissues
 Adult body cells are not all the same. There
are many kinds of cells, all specialized for
particular functions
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Body Tissues
 As a zygote (fertilized egg) divides, the
daughter stem cells gradually differentiate.
 Cell differentiation = changing size, shape,
structure, and activity to become more
specialized.
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Body Tissues
 Tissues = Groups of cells with similar structure and function
 Objectives for this unit:
 Know the different tissue types in the human body. For
each one, know:
 Where it’s found in the body
 Its function
 Its main features and its form (recognize by sight)
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Body Tissues
 Four primary tissue
types
 Nervous
(“Control”)
 Muscle
(“Movement”)
 Connective
(“Support”)
 Epithelium
(“Covering”)
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Nervous Tissue
 Cells: Neurons and nerve
support cells
 There are a variety of
different kinds of
neurons and support
cells. Different body
locations feature
different varieties.
 Location: Nervous
system - brain, spinal
cord, peripheral nerves
Figure 3.21
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Nervous Tissue
 Function: send
electrochemical
impulses to other
areas of the body
 Irritability
(reaction) and
conductivity
(control)
Figure 3.21
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Nervous Tissue
 Features:
 Neurons have a
highly
recognizable shape
 Nervous tissue
appears to be a
network of
neurons
Figure 3.21
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Nervous Tissue
 Usual ID Difficulty:
 Neurons typically
infiltrate other tissue
types
 Neuron support cells
harder to ID
Spinal cord, transverse section
Figure 3.21
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Muscle Tissue
 Three types of muscle tissue
 In all three, muscle cells are arrayed in
bunched chains called muscle fibers
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Skeletal Muscle
 Cells:
 Skeletal muscle cells
 Location:
 Any body muscles under conscious
control, attached to skeleton and/or skin
 Function:
 Skeletal muscle cells move an area of
the body by sliding over one another
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Skeletal Muscle
 Features:
 Long, cylindrical cells
 Cells are striated
(striped)
 Multinucleate (more
than one nucleus per
cell)
 Difficult to tell where
one cell ends and the
next begins
Figure 3.20a
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Cardiac Muscle
 Cells:
 Cardiac muscle cells
 Location:
 The heart
 Function:
 Cause heart to
contract/expand to
pump blood
(involuntary)
Figure 3.20b
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Cardiac Muscle
 Features:
 Long, cylindrical,
branching cells
 Cells are striated
 Uninucleate (one nucleus
per cell)
 Cells attach to each other
at intercalated disks,
appear as dark bands
 (Intercalated discs are
junctions that allow ions
to pass freely from cell
to cell, helping
excitatory impulses to
sweep across the whole
heart)
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Figure 3.20b
Smooth Muscle
 Cells:
 Smooth muscle cells
 Location:
 Surrounding hollow
organs - like stomach,
bladder, uterus, blood
vessels
 Function:
 Contract or expand
organs, involuntarily
(example: peristalsis)
Figure 3.20c
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Smooth Muscle
 Features:
 Long, cylindrical
cells
 No striations
 Uninucleate
Figure 3.20c
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Crime Scene Quiz
 1. A victim is found with two
bullet wounds, one in the
cranial cavity, and one that
shattered the sternum. There’s
one viscera splatter on the wall,
and another where the wall
meets the floor, indicating that
the victim was first shot while
standing, and then shot again
while slumped to the ground.
 A histologist examines the wall
splatter, and finds it is primarily
composed of blood, bone, and
these cells. Which bullet
wound was made first?
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Crime Scene Quiz
 2. An elderly woman is admitted to the emergency
room with a jagged stab wound to the mid-femoral
area. With her description of her assailant, the police
locate a suspect with a prior history of assault and
battery. They collect as evidence from his apartment a
knife that tests positive under luminol for blood, and
place him under arrest.
 Under questioning, he insists he has never encountered
the victim. Tissue is collected from the serrated blade
of the knife, and analyzed under a microscope. This is
what the crime scene investigators found.
 What should the police do now?
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Crime Scene Quiz
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