The document discusses the organization of the human body from cells to organ systems. It describes that cells form tissues, tissues form organs, and organs work together in organ systems to carry out important body functions. It then provides more detailed information about specific organ systems like the skeletal, muscular, integumentary, and nervous systems.

1. Body Organization
• Homeostasis – stable internal environment
• Tissue and organs (hox genes)
• All living organisms have cell(s)
• Multiple similar cells form tissue
• Tissue comes in 4 types
• Epithelial – skin
• Nervous – electrical messages
• Muscle – movement
• Connective – joins, supports, protects, insulates, nourishes
cushions (keeps organs from falling apart)

2. • Two or more tissues working together
form an organ
• Organs that work together are called
organ systems
• cells→tissue →organ →organ system
• The human body has 11 major organ
systems

3. Systems
• Integumentary – skin hair nails, protects
underlying tissue
• Muscular – move bones
• Skeletal – provides frame to support and
protect body parts (brain, heart, lungs and
spinal cord)
• Cardiovascular/circulatory – pumps and
transports fluids and blood

4. Sect 1 Cont.
• Nervous – receives and sends electrical
messages
• Lymphatic – returns leaked fluids to the
blood vessels and fights germs
• Digestive – breaks down food for
nutrients
• Endocrine – regulates body functions
through chemical messages (hormones –
ovaries and testes)

5. Sect 1 Cont.
• Respiratory – lungs absorb O2 and
release CO2
• Excretory – removes waste from the
blood and regulates body fluids
• Reproductive – male produces sperm,
female produces eggs
• S,L,I,M,E R,N C,R,E,D,
• Organ systems help the body maintain
homeostasis by working together

6. Skeletal System
• Skeletal system – bones, cartilage and
structures that connect bones to muscle
• Humans have 206 bones
• Bones are Living
• Used to support, protect, storage, and
blood cell production
• Composed of living cells called
osteoblasts

7. Cont.
• Two types of bone
– Compact – rigid and dense with no visible
space
– Spongy - contains many open space
• Provides strength and support
• Contains red marrow that makes red and
white blood cells (the blood cell factory)

8. Cont
• Cartilage – flexible tissue, the beginning of
bone
• By adulthood, cartilage is replaced by
bone
• Only the nose and ears remain cartilage in
adulthood
• Located between bones (joints) in adults
to cushion bones

9. Sec 2 Cont
• Joint – the place where two bones connect
• Depending on type of joint allows for
movement when muscles contract and
pull on bone
• Types of joints_
– Fixed – very little movement (skull)
– Ball and socket – movement in all directions
(shoulder)

10. Cont
– Hinge – movement in two directions (flex or
extend) knee or elbow
– Sliding – gliding movement, spine
• Ligament – strong bands of connective
tissue that keep joints together (bone to
bone)

11. Muscular System
• Muscular system – made of muscle and
connective tissue that attached muscle to
bone
• Three types of muscle:
– Smooth – found in the digestive track and
blood vessels
– Cardiac – found only in the heart
– Skeletal – attached to bone for movement

12. Cont.
• Muscle action:
• Voluntary – under your control
• Involuntary – not under your control
(smooth muscle and cardiac)
• Tendons – connects muscle to bone
• Muscle movement is caused by electrical
signals transmitted to the brain

13. Cont.
• Muscles pull on bone to create movement
• Muscle movement is in pairs and moves in
two directions
• Flexor – muscle bends
• Extensor – muscle is straightened
• Type of exercise:
• Aerobic – strengthens heart and increase
endurance

14. Cont.
• Resistance – muscle overcomes weigh
• Anabolic steroids – resembles
testosterone (male sex hormone)
• Causes heart, liver, kidney damage, high
blood pressure, stunted growth, roid rage,
infertility

15. Integumentary System
• Integumentary system – skin, hair and
nails
• Integumentary means “covering”
• Keeps H2O in and foreign particles out,
first line of defense for the body
• Largest organ in the body
• Not only on exterior of the body but also
on the interior

16. Cont.
• Melanin – darkening chemical in skin and
hair that determines color
• Located in the upper layer of skin
(epidermis)
• Absorbs UV light
• Two layers of skin:
• Epidermis – (“epi” means on top of) made
of epithelial tissue

17. Cont.
• Thick as two sheets of paper
• Most epidermal cells are dead and filled
with keratin, a protein that makes skin
tough
• Dermis - under the epidermis
• Fibers of protein called collagen
• Where structures of skin are located
• Nerve endings, sweat glands, hair follicles,
blood vessels, muscle fiber, oil glands

18. Cont.
• 75% of the air you breathe is dead skin
cells
• Body replaces skin every 3 weeks

19. Nervous system
• Nervous system – a command post
collecting and processing data
• Two divisions:
• 1. central nervous system (CNS)
– Includes the brain and spinal cord
– Processes all electrical messages coming into
and out of the brain

20. • 2. peripheral nervous system (PNS)
– Made of nerves that connect all areas of the body to
the CNS
• PNS – composed of neurons, specialized cells
that transfer messages in the form of fast
moving electrical signals
• Signals are called impulses, location of impulse
is the synapse
• Impulse can travel as fast as 150 m/s or as slow
as .2 m/s

21. • Neuron structure – neurons consist of a cell
body, dendrites and axons
• Cell body – large region in the center containing
a nucleus and organelles
• Dendrites – short branched extensions that
neurons usually use to gather info from other
cells
• Neurons may have many dendrites which allow
it to receive impulses from thousands of cells

22. • Axon very short or very long fiber used to
transmit info from the cell body
• Some axons have branches called axon
terminals that allow info to travel to other
cells
• Receptors – structures that detect
changes inside and outside the body

23. • Sensory neurons – specialized neurons that
gather info in and around the body
• Motor neurons – neurons that send impulses
from the brain and spinal cord to other systems
“motor” meaning to move
• Nerves – connect CNS to the rest of your body
• Axons bundled together with blood vessels and
connective tissue
• Most carry sensory and motor neurons

24. • CNS – brain, largest organ in the nervous
system
• Processes are describe as involuntary
since the response happens automatically
• Other actions are voluntary, movement is
made consciously

25. • Brain is composed of 3 parts, contains 100
billion neurons
• Cerebrum – largest part of the brain
• Where thinking and memories are stored
• Controls voluntary motion allows for the sense of
touch, light, sound, odors, taste, pain, heat and
cold
• Two hemispheres (halves) the left side directs
the right side of the body and the right side
directs the left side of the body

26. • Left hemisphere controls reading,
speaking, writing and problem solving
• Right side controls imagination,
appreciation, and creativity
• Cerebellum – second largest organ in the
CNS
• Located underneath the back of the
cerebrum

27. • Receives sensory impulses from skeletal
muscle and joints
• Controls balance
• Medulla (oblongata)– connects brain to
spinal cord
• About 3cm long controls all involuntary
activities like heart rate, breathing and
blood pressure

28. • Spinal cord – part of the CNS
• About the size of your thumb
• Composed of neurons and bundles of
axons that pass impulses to and from the
brain
• Protected by the vertebrae
• Injuries can stop sensory info from
traveling