1. 33.1 Skeletal System
KEY CONCEPT
The skeletal system includes bones and tissues that
are important for supporting, protecting, and moving
your body.

2. 33.1 Skeletal System
Your skeletal system is made up of the appendicular and
axial skeletons.
• The skeletal system protects, supports, and moves the
body.

3. 33.1 Skeletal System
• The appendicular skeleton includes legs, arms, feet and
hands.
– allows for movement
– includes bones called girdles that connect limbs to
body

4. 33.1 Skeletal System
• The axial skeleton includes the skull, rib cage, and spinal
column.
– supports body and protects
skull
tissues
– allows for limited movement
rib
breastbone
vertebra

5. 33.1 Skeletal System
• Cartilage is connective tissue between bones.
– cushions bones
– allows for smooth movement
– connect two bones
cartilage

6. 33.1 Skeletal System
Bones connect to form joints.
• Joints are places were two bones meet.
• There are three types of joints.
– fibrous, which does not fibrous joint
allow for movement

7. 33.1 Skeletal System
Bones connect to form joints.
• Joints are places were two bones meet.
• There are three types of joints.
– cartilaginous, which allows partial movement
cartillage

8. 33.1 Skeletal System
Bones connect to form joints.
• Joints are places were two bones meet.
• There are three types of joints.
– synovial, which allows
for greater movement

9. 33.1 Skeletal System
• Ligaments are long bands of tissue that connect bones
across a joint.
ligament

10. 33.1 Skeletal System
• There are several types of synovial joints.
– gliding
– pivot GLIDING JOINT
– ball-and-socket
PIVOT JOINT
– saddle
– hinge BALL-AND-SOCKET JOINT
SADDLE JOINT
HINGE JOINT

11. 33.1 Skeletal System
Bones are living tissue.
• Bone is made of compact bone tissue and spongy bone
tissue.
Compact bone
Spongy bone

12. 33.1 Skeletal System
• Compact bone is hard and dense.
– Osteocytes (bone cells) maintain compact bone rings.
– Haversian canals allow blood vessels in the bone.
blood vessel
osteocytes
Haversian canals

13. 33.1 Skeletal System
• Spongy bone protects red or yellow bone marrow.
– Red bone marrow produces blood cells.
– Yellow bone marrow is mostly fat.
Periosteum
A layer of connective
tissue that covers bone
Red bone marrow

14. 33.1 Skeletal System
• Calcification is the process of building hard bone.
– combines collagen and calcium phosphate
– transforms cartilage into hard bone during childhood
osteocyte
compact bone

15. 33.1 Skeletal System
KEY CONCEPT
Muscles are tissues that can contract, enabling
movement.

16. 33.1 Skeletal System
Humans have three types of muscle.
• The muscular system moves substances throughout the
body.
– bones of the skeletal system
– food through digestive system
– blood through circulatory system
– fluids through excretory system

17. 33.1 Skeletal System
• There are three types of muscle tissue.
– skeletal muscle
– smooth muscle
– cardiac muscle
SKELETAL MUSCLE SMOOTH MUSCLE CARDIAC MUSCLE

18. 33.1 Skeletal System
• Skeletal muscle attaches to the skeleton by tendons.
– Tendons connect muscle to bone.
– Skeletal muscles are mostly voluntary.
SKELETAL MUSCLE

19. 33.1 Skeletal System
• Smooth muscle lines organs and is involuntary.
– move food through digestive organs
– empty liquid from the bladder
– control width of blood vessels
Smooth muscle
around this artery allows the
artery to regulate blood flow
by shrinking and expanding.
SMOOTH MUSCLE

20. 33.1 Skeletal System
• Cardiac muscle is found only in the heart.
– pumps blood throughout body
– controlled by pacemaker
– contains more mitochondria than skeletal muscle cells
CARDIAC MUSCLE

21. 33.1 Skeletal System
Muscles contract when the nervous systems causes
muscle filaments to move.
• Muscle fibers are cells of the muscular system.
muscle fiber
muscle

22. 33.1 Skeletal System
• Myofibrils are long strands of protein in the muscle fiber.
myofibril muscle fiber
muscle

23. 33.1 Skeletal System
• Each myofibril is divided into sarcomeres.
• Sarcomeres contain filaments that cause contraction.
muscle fiber
myofibril
sarcomere
muscle

24. 33.1 Skeletal System
• Each myofibril is divided into sarcomeres.
• Sarcomeres contain filaments that cause contraction.
– Actin filaments are pulled during contraction.
– Myosin filaments pull actin during contraction.
RELAXATION
myosin
M line Z line
CONTRACTION

25. 33.1 Skeletal System
• Neuron stimulates muscle at the neuromuscular junction.
neuromuscular
junction
neuron
MUSCLE

26. 33.1 Skeletal System
• Neuron stimulates muscle at the neuromuscular junction.
– Neurotransmitters
cause calcium regulatory protein
channels in the
sarcomere to
open.
– Calcium exposes
binding sites.
– Myosin binds to
actin and pulls it.
actin
– As the sarcomere
shortens, the
muscle contracts. myosin
Z line

27. 33.1 Skeletal System
KEY CONCEPT
The integumentary system has many tissues that
protect the body.

28. 33.1 Skeletal System
The integumentary system helps maintain homeostasis.
• The integument is the body system that surrounds all
your other organ systems.

29. 33.1 Skeletal System
The integumentary system helps maintain homeostasis.
• The integumentary system consists of many parts.
– skin
– hair
– nails
– oil glands
– sweat glands
– proteins,
such as
keratin

30. 33.1 Skeletal System
• Integumentary system removes substances from the body.
– water
– salts
– urea
pore
sweat
glands

31. 33.1 Skeletal System
The integumentary system consists of many different
tissues.
• The outermost layer of
the skin is the epidermis. pore
– dead skin cells
– oils
– pores epidermis

32. 33.1 Skeletal System
• Cells in the epidermis produce keratin and melanin.
– Keratin makes cells
waterproof and tough
feeling.
– Melanin is a dark
pigment that
absorbs UV rays.

33. 33.1 Skeletal System
• The dermis contains most of the tissues in the skin.
– sweat glands
– oil glands
– pressure receptors
– blood vessels
– hair follicles
hair follicle
oil gland
dermis
pressure
receptors
sweat gland

34. 33.1 Skeletal System
• A hair follicle is pit of cells that produces hair.
• The dermis also produces elastin and collagen.
– Elastin makes skin flexible.
– Collagen gives skin its shape.

35. 33.1 Skeletal System
• Beneath the dermis is a layer of fat.
fat layer