An Introduction to the Body Systems

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Nov 10, 2013 (3 years and 5 months ago)

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An Introduction to the
Body Systems


The Human Body Plan


Skeletal System


Muscular System


Integumentary System

Objectives


Describe

four types of tissues that make up the
human body.



Explain

how tissues, organs, and organ
systems

are organized.



Summarize

the functions of the primary organ
systems in the

human body.



Identify

the five human body cavities and the
organs that

each contains.


Levels of Structural
Organization

Chemical



atoms combine to form molecules

Cellular



molecules interact to make up cells

Tissue



cells are grouped into tissue

Organ



tissues compose organs

Organ system



organs function together to
form organ systems

Organism (individual)



made up of the organ
systems

Body Tissue


All tissues are a collection of cells
that have a similar structure and that
work together to perform a particular
function.



Four types of body tissue:


1.
Muscle tissue

2.
Nervous Tissue

3.
Epithelial Tissue

4.
Connective Tissue




1.
Muscle Tissue


composed of cells that can contract
in a coordinated fashion.



The human body has three types of
muscle tissue: skeletal, smooth, and
cardiac.



Skeletal muscle

moves the bones
in your trunk, limbs, and face.



Smooth muscle

handles body
functions that you cannot control
consciously
.



Cardiac muscle,

found in your
heart, pumps blood through your
body.


Chapter

45

Body Tissues,
continued

2. Nervous Tissue



Nervous tissue

contains cells,

or neurons, that

receive and

transmit messages

in the form of

electrical impulses.



Neurons

are nerve cells that are
specialized to receive and send electrical
impulses

Chapter

45

Nervous Tissue,
continued


Nervous tissue can be found throughout
the human body and has various
functions.



For example, nervous tissue can be found in
the brain and sensory organs and is used to
interpret sensory information.

Chapter

45

Body Tissues,
continued

3. Epithelial Tissue
-

tissue that is
composed of a sheet of cells and that
covers a body surface or lines a body
cavity.



Epithelial tissue is found in various
thicknesses and arrangements, depending
on where it is located.

Chapter

45

Body Tissues,
continued


Epithelial Tissue,
continued


Each epithelial layer


is formed from cells


that are tightly bound


together, often


providing a protective


barrier for these


surfaces.

Chapter

45

Body Tissues,
continued

4. Connective Tissue


is a tissue that has
a lot of intracellular
substance and that
connects and
supports other
tissues.

Chapter

45

Body Tissues,
continued


Connective Tissue,
continued



Connective tissues are the most
abundant and diverse of the four types
of tissue and contain a substance called
matrix
.



Matrix

is an intracellular substance that
gives connective tissue its strength and
flexibility and can be solid, semisolid, or
liquid.

Chapter

45

Human Body Tissues

Chapter

45

Organs and Organ Systems


An
organ

consists of various tissues
that work together to carry out a
specific function.



Groups of organs interact in an organ
system.



Organ systems work together to
function in an efficient, integrated
manner.

Organs and Organ Systems


Integration of Organ Systems



An even higher level of organization is the
integration of organ systems.



The integration of organ systems can be
described as each organ system having
organs associated with it according to that
organ’s primary function. This is so the
organ system can work more efficiently.


Body Cavities


Many organs and organ systems in the
human body are housed in compartments
called body cavities.



These cavities protect internal organs from
injuries and permit organs to function while
remaining securely supported.



Each human cavity can contains one or more
organs.


Body Cavities
continued…


The human body has five main body
cavities, including the cranial cavity, the
spinal cavity, the thoracic cavity, the
abdominal cavity, and the pelvic cavity.



The
cranial cavity

is the cavity that
contains, supports, and protects the brain.



The
spinal cavity

is the cavity that
contains, supports, and protects the spinal
cord.


Body Cavities
continued…


The
thoracic cavity

is the cavity that contains,
supports, and protects the heart, esophagus, and the
organs of the respiratory system.



The
abdominal cavity

is the cavity that contains,
supports, and protects the digestive system.



The
pelvic cavity

is the cavity that contains,
supports, and protects the organs of the
reproductive and excretory systems

Objectives:

Skeletal System


Distinguish

between the axial skeleton and
the appendicular skeleton.



Explain

the function and structure of bones.



Summarize

how bones develop and
elongate.



List

three types of joints and give an example
of each.



Describe

a common disorder that affects the
skeleton

The Skeletal System


Composed of bone, cartilage, and
ligaments


Protects and supports body organs


Provides the framework for muscles


Site of blood cell formation


Stores minerals


The Skeleton


A skeleton is the bones of a human or
animal body that form the framework of
the body, support the muscles and
organs, and protect the inner organs.



The variation in size and shape among
the bones that make up the skeleton
reflects their different

roles in the body.


Subsections of the
Human Skeleton

o
The purple is the
axial
skeleton

and the yellow is
the
appendicular skeleton
.


The Skeleton Is Divided Into
Two Distinct Parts:

1. The
axial skeleton

consists of bones
that form the axis of
the body and
support and protect
the organs of the
head, neck, and
trunk.



Click on these links to
read about the axial
parts of the body.


The skull


The sternum


The ribs


The backbone

The Appendicular Skeleton

2. The
appendicular
skeleton

is
composed of bones
that anchor the
appendages to the
axial skeleton.



Click on these links to
read about the
appendicular parts of
the body.


The lower body


The upper body


The shoulders


The pelvic area


Axial skeleton


skull (cranium and facial bones)


hyoid bone (anchors tongue and muscles
associated with swallowing


vertebral column (vertebrae and disks)


thoracic cage (ribs and sternum)



Appendicular skeleton


pectoral girdle (clavicles and scapulae)


upper limbs (arms)


pelvic girdle (coxal bones, sacrum, coccyx)


lower limbs (legs)


Bone Function and Structure


The bones that make up the skeleton function
in a variety of ways


support muscles


protect internal organs


help movement


play vital roles in important metabolic processes.



Bones do not make

up most of a body’s
mass.


Being “big boned” is no excuse for being
overweight!


Types of Bones

The bones of the body fall into four general categories:

1.
Long bones

are longer than they are wide and work
as levers. The bones of the upper and lower
extremities are of this type.

2.
Short bones

are short, cube
-
shaped, and found in
the wrists and ankles.

3.
Flat bones

have broad surfaces for protection of
organs and attachment of muscles

4.
Irregular bones

are all others that do not fall into the
previous categories. They have varied shapes,
sizes, and surfaces features and include the bones
of the vertebrae and a few in the skull.


Bone Function and Structure


Long Bone Structure



A long bone’s surface is covered by a
tough membrane called the periosteum.



Periosteum is a white, double layered
membrane that covers the entire surface
of bone except for the joint surfaces and is
richly supplied with nerve fibers and blood
vessels.

Long Bone Structure,
continued


Under the
periosteum

is a hard material
called compact bone, and this part of the
bone gives all bones their strength and
rigidity.



Compact bone

is composed of cylinders
made of mineral crystals and protein fibers
.



Beneath some compact bone is a network of
connective tissue called spongy bone.



Spongy bone

is less dense bone tissue that
has many open spaces.



Bone Function and Structure
continued…


Bone marrow

is a soft tissue inside
some bones that can be either red or
yellow.



The type of bone marrow present
determines both its composition and
function.


Bone Function and Structure
continued…


Injury and Repair



Despite their strength, bones will crack or
even break if they are subjected to certain
situations or are overused.



A crack or break is referred to as a
fracture.



A
fracture

is an injury in which the
tissue of a bone is broken.


Bone Development


During fetal development, some bones
that were originally cartilage will slowly
be replaced by actual bone. This
process is called

ossification
.



Humans are born with over 300 bones,
but adults have about 206 bones.



Where are the 206 Bones?


22 bones in skull


6 in middle ears


1 hyoid bone


26 in vertebral column


25 in thoracic cage



4 in pectoral girdle


60 in upper limbs


60 in lower limbs


2 in pelvic girdle


Bone Development


Bone Elongation


Bones continue to grow after a person’s
birth.



Bone elongation and growth take place
near the ends of long bones in an area
known as the
epiphyseal plate
.



The epiphyseal plate is found at the joint ends
of long bones and is composed of cartilage.
This area of bone will eventually become
mature bone.


Joints


The place where two bones meet is
known as a
joint



Three major kinds of joints are found in
the human body


Fixed


Semimovable


Movable


Types of Joints


Fixed Joints


A joint at which no movement occurs


Semimovable Joints


A joint that will permit limited movement


Cartilage can be involved to help these
joints move.


Movable joint


-

A joint at which a wide range of motion
occurs.


There are different types of movable joints,
including hinge, ball
-
and
-
socket, pivot,
saddle, and gliding.

Movable Joints


A
hinge joint

allows limited movement in only one
plane.




A
ball
-
and
-
socket joint

is another type of
moveable joint and allows 360 degree movement
in 2 planes.



A
pivot joint

allows 180 degree movement in only
one plane.



A
saddle joint

will allow 360 degree movement in
only one plane.



A
gliding joint

allows bones to slide over one
another.


Gliding Joint

Joint Structure



Joint structure helps movable joints deal
with the pressure and stress of everyday
life.



Joints are covered with cartilage and
secrete
synovial fluid

to reduce friction.
Joints are also connected with
ligaments

(hold bone to bone) and
tendons

(hold
muscle to bone) to aid in joint movement.



Even with all this protection a joint can still
be injured.


Joints
continued…


The term
arthritis

is used to describe
disorders that cause painful, swollen
joints.



Rheumatoid arthritis

develops when the
immune system begins to attack body tissues,
and joints become stiff and deformed.



Osteoarthritis

is a degenerative joint disease in
which the cartilage

covering the surface of
bone becomes thinner and rougher.


Other Links


*
Site of Anatomy
Terms


*
Listen to audio
recordings about the
skeletal system


*
Click on any part of
the skeleton and it will
tell you about that
part of the body



Objectives:

Muscular System


Distinguish

between the three types
of muscle tissues.



Describe

the structure of skeletal
muscle fibers.



Explain

how skeletal muscles
contract.



Describe

how muscles move bones.



Explain

the process in which a muscle
becomes fatigued.


Muscular system


Composed of
muscles and
tendons


Allows
manipulation of
the environment,
locomotion, and
facial expression


Maintains
posture


Produces heat


Muscle Types


A muscle is an organ that can contract in a
coordinated fashion and includes muscle tissue,
blood vessels, nerves, and connective tissue.



Their ability to contract and relax not only
enables the body to move, but also provides the
force that pushes substances, such as blood
and food, through the body.



The human body has three types of muscle

tissues: skeletal, smooth, and cardiac
.


Skeletal Muscle


Skeletal muscles consciously control
the moving parts of the body and are
often referred to as
voluntary muscles
.



Skeletal muscles are made up of
muscle fibers.


Muscle fibers consist of multinucleated
elongated cells with light and dark stripes.
These stripes are called
striations
.


Skeletal Muscle
continued…


Muscle fibers are grouped into
bundles called
fascicles
.



Groups of fascicles are bound
together by connective tissue to
form a muscle.



The connective tissue in skeletal
muscle cells can unite

to form
tendons.


Smooth Muscle


Smooth muscles are spindle
-
shaped, have a
single nucleus, and interlace to form sheets.



Smooth muscle lacks striations, and the
connective tissue that surrounds it cannot
form tendons.



Smooth muscle forms the walls of the
stomach, intestines, blood vessels, and other
internal organs. Because most of its
movements cannot be consciously
controlled, smooth muscle is

referred to as
involuntary muscle
.


Cardiac Muscle


Cardiac muscle makes up the
walls of the heart.



Cardiac muscle shares some
characteristics with both skeletal
muscle and smooth muscle.



As with skeletal muscle, cardiac
muscle tissue is striated; as with
smooth muscle, it is involuntary

and
each cell has one nucleus.


Muscular Contractions


Muscle contraction is an all
-
or
-
none
response

either the fibers contract or
they remain relaxed.



The force of a muscle contraction is
determined by the number of muscle
fibers that are stimulated.


As more fibers are activated
, the force of
the contraction increases.


Muscular Movement of Bones


Muscles are attached to the outer membrane
of bone, the periosteum, either directly or by
a tough fibrous cord of connective tissue
called a
tendon
.



The point where the muscle attaches to the
stationary bone is called the
origin
.



The point where the muscle attaches to the
moving bone is called the
insertion
.


Muscular Movement of Bones


Most skeletal muscles are arranged in
opposing pairs, and muscles move bones by
pulling them.



The muscle that bends a joint is known as a
flexor
.



A muscle that straightens a joint is known as
an
extensor
.



In order for smooth movement, one muscle
in a pair must contract while the opposing
muscle relaxes.


Opposing Muscles in the Arm

Objectives:

Integumentary System


Describe

the functions of the skin
.



Distinguish

between the two layers
that form skin.



Identify

two types of glands found in
the skin, and describe their functions.



Describe

the structure of nails.



Describe

the structure of hair.


Layers of Skin:

Epidermis and Dermis


Epidermis


Outer layer


From the Greek
epi
, meaning “on” or “upon”
and
derma

meaning “skin”


Composed of scaly epithelial cells, top layer
mostly dead


Cells filled with the protein keratin which gives
skin a tough, leathery, waterproof quality


Skin color determined by the amount of
melanin

in the lower layers of the epidermis

Layers of Skin:

Epidermis and Dermis


Dermis


The dermis is the inner layer of skin and is
composed of living cells and other specialized
structures such as:


Sensory neurons, blood vessels, muscle fibers,
hair follicles, and glands



These specialized cells help the skin protect
the body as much as possible

Glands


The skin contains
exocrine glands, which
are glands that release
secretions through
ducts.



The main exocrine
glands present in the
skin are
sweat glands

and
oil glands
.



help regulate the bodies temperature.



Sweat glands are
distributed throughout the
body and release excess
water, salts, and urea
.



Oil glands secret a
substance called sebum.



Sebum is an oily secretion
that prevents excess water
loss, softens hair and skin,
and protects the body by
being mildly toxic to some
bacteria.




Acne
occurs when the
ducts of oil glands become
clogged with excessive
amounts

of sebum, dead
cells, and bacteria
.


Cross section of Skin

Hair & Nails


Nails help protect the
fingers and toes by
forming nail roots under
skin folds at the base and
sides of the nail.



Nails are also made
primarily of keratin and
rest on a bed of tissue
filled with blood vessels.



Hair protects and
insulates the body and is
produced by hair follicles,
which are clusters of cells
at the base of deep
dermal pits.



Hair is composed of
keratin and is kept soft by
the oil glands associated
with the hair follicle.



Hair color is the result of
the presence of the
pigment melanin in the
hair shaft.