Download human body systems

HUMAN BODY SYSTEMS
Part 1: Integumentary, Muscles, and
Skeletal Systems
Fun Facts about… the Integumentary
System
• It contains your body’s
largest organ… your skin.
• An average adult's skin
spans 21 square feet,
weighs nine pounds, and
contains more than 11
miles of blood vessels.
• The skin releases as much
as three gallons of sweat
a day in hot weather
• In a lifetime, the average
person sheds enough skin
cells to fill an entire 2
story house. In one
minute, you can lose
between 30,000 and
40,000 skin cells.
Why is it important?
• Serves as a barrier against
infection and injury
• Helps regulate body
temperature
• Removes waste products
from the body
• Provides protection against
UV rays
• Contains sensory receptors
Skin
Contains 3 layers:
Epidermis
• The outermost layer of skin
– Contains two layers of cells
• The outermost layer is made of dead cells
• The innermost layer of cells undergo rapid cell division
• Contains melanocytes which produce
MELANIN
– A dark pigment that is responsible for skin color
– Helps protect the skin from damage by absorbing
UV rays from the sun
Dermis
• The middle layer of skin
• Contains: blood vessels,
nerve endings, sweat
glands, sensory receptors,
hair follicles, and smooth
muscles
• Responsible for interacting
with other body systems to
maintain homeostasis by
regulating body
temperature.
Hypodermis
• The innermost layer of skin
• The storage site of most body fat
• Fastens the skin to underlying tissues and
organs, insulates the body, and absorbs shocks
from impacts to the skin.
Hair
• On the scalp, it
protects from UV
rays and provides
insulation
• In the nostrils, ear
canals, and around the
eyes, it prevents dirt
and other particles from
entering the body
Nails
• Covers and protects the
tips of fingers and toes
• Made of KERATIN
– A tough, fibrous protein
Fun facts about… the Muscular System
• The busiest muscles in your body are the eye
muscles, which approximately move more than
100,000 times in a day
• Muscles cannot push, they can only pull.
• There are approximately 640 muscles in the body.
– The largest is your gluteus maximus.
– The smallest are in your middle ear.
Types of Muscles
• Cardiac
• Skeletal
• Smooth
Cardiac Muscle
• Found only in the
heart
• Striated
• One nucleus
Skeletal Muscle
• Responsible for
voluntary
movements
• Striated
• Many nuclei
Smooth Muscle
• Responsible for
involuntary
movements
• Not Striated
• One nucleus
How do Skeletal Muscles Work?
• Muscles contract when thin filaments (ACTIN)
slides over thick filaments (MYOSIN)
Fun Facts about…the Skeletal System
• A baby is born with 300 bones, but an adult
only has 206.
• 54 of those bones are in your hands.
• Humans and giraffes have the same number
of bones, but giraffes’ vertebras are much
longer.
Why is it important?
• Supports the body
• Protects internal
organs
• Stores mineral
reserves
• Provides a site for
blood cell formation
Two Parts
AXIAL SKELETON
• Skull
• Ribs
• Vertebral Column
APPENDICULAR
SKELETON
• Arms
• Shoulder
• Legs
• Pelvis (Hip)
Structure of Bones
• Periosteum:
– Outermost layer of bone
– Made of connective
tissue
– Blood vessels pass
through the periosteum
to deliver oxygen and
nutrients to the bone.
Structure of Bones
• Compact Bone:
– Middle layer of bone
– Dense layer that
protects the bone from
breaking
– Contains tubes that
contain blood vessels
and nerves
Structure of Bones
• Spongy Bone:
– Inner layer of bone
– Resembles a
sponge, but adds
strength to a bone
without adding
mass
Structure of Bones
• Bone Cavity:
– Contains BONE
MARROW
• Yellow Marrow:
mainly fat cells
• Red Marrow:
produces red
blood cells,
some kinds of
white blood
cells, and
platelets