1. Unit 18 (ch. 26) Support & Movement
What’s another word for movement?
locomotion
Unit 18 (ch. 26) Support & Movement
Which two systems work together to allow support & movement? Muscular & skeletal system
What’s another word for movement? locomotion
Which two systems work together to allow support & movement?
muscular & skeletal

2. The Role of the Skeleton
What are the 3 main functions of the skeletal system?
support the body
protect organs
aid in movement
provides attachment site for muscles
Protection (skull, ribs, breast bone, vertebrae) of organs
support (thigh bones = femur)
Locomotion/movement (attachment for muscles)
ALSO: Make blood cells (in bone marrow) & store calcium (give bones strength)

3. 2 Types of Skeletal Systems
Exoskeletons
Endoskeletons
What’s the difference?
Difference Exoskeleton  cover body Endoskeleton  inside body

4. Skeletal Systems: Exoskeletons
found in arthropods
“jointed legs”
made of chitin & protein
Chitin is a carbohydrate
Advantages? Tough & rigid  Protection + support + locomotion (movement) waxy outer surface  Helps prevent water loss
Disadvantages? Limits size (b/c of weight) & growth (exoskeleton does not grow) What must do to exoskeleton in order to grow?  molt

5. Skeletal Systems: Exoskeletons
Advantages?
provides protection & support (tough & rigid)
allows for locomotion (movement)
helps prevent water loss (waxy outer surface)
Disadvantages?
limits size (b/c of weight)
limits growth (exoskeleton does not grow)
What must an organism do to its exoskeleton in order to grow?
molt
Chitin is a carbohydrate
Advantages? Tough & rigid  Protection + support + locomotion (movement) waxy outer surface  Helps prevent water loss
Disadvantages? Limits size (b/c of weight) & growth (exoskeleton does not grow) What must do to exoskeleton in order to grow?  molt

6. Skeletal Systems: Endoskeletons
Found in vertebrates
Similarities to exoskeleton?
protection (skull, ribs, breast bone, vertebrae) of organs
support (thigh bones = femur)
locomotion (attachment for muscles)
Differences from exoskeleton?
inside soft tissue, not on outside
bones specialized for certain functions & types of movement
does not limit size (no need to molt)
makes blood cells
Similarities to exoskeleton? Protection (skull, ribs, breast bone, vertebrae) of organs, support (thigh bones = femur), and locomotion (attachment for muscles)
Differences from exoskeleton? Lies inside soft tissue not on outside, subdivided into different parts (bones), which are specialized for certain functions & types of movement, does not limit space/does not need to molt, makes blood cells
Advantages? Protect internal organs, size & growth not as limited as w/ exoskeleton, bones are stronger than exoskeleton so size limit is bigger
Disadvantages? Little external protection
206 bone in adult human

7. Skeletal Systems: Endoskeletons
Advantages?
Protect internal organs
Growth not as limited as w/ exoskeleton (no need to molt)
Size limit is bigger (bones are stronger than exoskeleton)
Disadvantages?
little external protection
Similarities to exoskeleton? Protection (skull, ribs, breast bone, vertebrae) of organs, support (thigh bones = femur), and locomotion (attachment for muscles)
Differences from exoskeleton? Lies inside soft tissue not on outside, subdivided into different parts (bones), which are specialized for certain functions & types of movement, does not limit space/does not need to molt, makes blood cells
Advantages? Protect internal organs, size & growth not as limited as w/ exoskeleton, bones are stronger than exoskeleton so size limit is bigger
Disadvantages? Little external protection
206 bone in adult human

8. Tissues of the Skeletal System
What types of tissue make up the skeletal system?
cartilage
bone
ligaments

9. Cartilage What is cartilage? Where is cartilage found?
A tough, flexible tissue that doesn’t store calcium, so it is less dense than bone.
Where is cartilage found?
mostly at the ends of bone
Why?
acts as a cushion for joints
Where is cartilage found? at the ends of bones in adult (to provide for smooth joint surface), as rings around the trachea to prevent collapse, most of the skeleton in the vertebrate fetus & a number of parts of juvenile skeleton,
Density = mass/volume (higher density = more mass per unit volume, so more compact)

10. Bone… Living or Not? Is bone living?
Yes, even though it’s hard & made of minerals, bone IS a LIVING tissue that grows.
ossification (replacement of cartilage with bone & addition of minerals such as calcium)
Think about it… Are you the same height as you were:
when you were a baby?
When you were a young child?
last year?
3 types of bone cells
Osteoblasts – cells that form new bone through ossification – replacement of cartilage or membrane by bone – take calcium from blood
Osteocytes -- are mature osteoblasts found in most formed bone tissue
Osteoclasts break down bone
Ossification = replacement of cartilage w/ bone by activity of osteoblasts & addition of minerals such as calcium compounds (taken from blood) Occurs in most bones Not completed until ~25 years old
Some cartilage remains at ends to provide smooth joint surfaces

11. Bone Structure 3 types of bone cells osteoblasts osteocytes
form new bone
ossification
osteocytes
mature osteoblasts
in most formed tissue
osteoclasts
break down bone
Osteoblasts – cells that form new bone through ossification – replacement of cartilage or membrane by bone – take calcium from blood
Osteocytes -- are mature osteoblasts found in most formed bone tissue
Ostoeclasts break down bone

12. Bone Structure What types of tissues are found in bone?
Interactive Bone Diagram
What types of tissues are found in bone?
compact (solid) bone
hard part of bone
very strong b/c stores calcium
usually along outer edge
spongy bone
has many empty spaces
usually near end of bone
lightweight, but strong
Periosteum – tough outer membrane, supplies nerves and blood vessels to Haversian canal, contains cells needed for growth & repair, point of attachment for muscle
2 types of bone tissue compact bone  shafts of long bones, hard & compact, made of alternating layers of collagen (protein) & minerals & contains many tiny channels called Haversian canals which carry blood vessels & nerves that supply osteocytes in the bone tissue, marrow in central hollows of many bones (red marrow in flat bones & ends of long bones produces red blood cells, some white blood cells, & platelets, & yellow marrow in hollow interior of long bones stores fat), marrow also functions in formation of bone cells
spongy bone  ends of long bones, under a layer of compact bone, composed of a system of cavities & intersecting plates

13. Bone Structure periosteum (membrane) marrow covers bone
Interactive Bone Diagram
periosteum (membrane)
covers bone
supplies nerves & blood vessels to Haversian canals
contains cells needed for growth & repair
attachment point for muscles
marrow
soft center in bone
makes blood cells
Periosteum – tough outer membrane, supplies nerves and blood vessels to Haversian canal, contains cells needed for growth & repair, point of attachment for muscle
2 types of bone tissue compact bone  shafts of long bones, hard & compact, made of alternating layers of collagen (protein) & minerals & contains many tiny channels called Haversian canals which carry blood vessels & nerves that supply osteocytes in the bone tissue, marrow in central hollows of many bones (red marrow in flat bones & ends of long bones produces red blood cells, some white blood cells, & platelets, & yellow marrow in hollow interior of long bones stores fat), marrow also functions in formation of bone cells
spongy bone  ends of long bones, under a layer of compact bone, composed of a system of cavities & intersecting plates

14. Ligaments What are ligaments?
connective tissue: holds bone to bone at joints
What holds bones to other bones? connective tissue called ligaments (made of collagen & some elastic fibers)
Muscles also play a role

15. Joints What is a joint? What allows joints to move smoothly?
where bones come together
What allows joints to move smoothly?
cartilage covering the end of the bones
fluid-filled bags between cartilage & bone
Ends of bones covered with cartilage provide smooth joint surfaces Fluid-filled bags between cartilage & bone (= bursa) Why? Cushion to prevent bones from rubbing against each other

16. types Types of Joints fixed movable ball & socket hinge pivot gliding
gliding joint
types
fixed
movable
ball & socket
hinge
pivot
gliding
Ends of bones covered with cartilage provide smooth joint surfaces Fluid-filled bags between cartilage & bone (= bursa) Why?
Most are movable What holds them together? Muscles & connective tissue called ligaments (made of collagen & some elastic fibers
Classification of Joints Animation

17. Fixed Joints Are not connected by ligaments. Do they move?
Also known as immovable joints or sutures.
What is an example?
skull
Examples individual bones of skull
mobility? Fixed joints in the skull create flexibility during birth b/c not fused yet (“soft spots”), in adults fused together (not connected by ligaments), connected by fibrous connective tissue
Also known as immovable joints or sutures

18. Types of Movable Joints
1. ball & socket
In which direction(s) does it move?
rotate, front-back, side-side
most mobility of all joints
What are examples?
hip, shoulder
Examples  shoulder (end of humerus = rounded knob, shoulder/scapula = depression) & hip (end of femur = rounded knob, pelvis = depression)
most mobility How can it move? Rotate, move front–back, move side-side

19. Types of Movable Joints
2. hinge
In which direction(s) does it move?
open-closed (only in 1 direction)
like a door
What are examples?
elbow, knee
Examples Elbow, knee, fingers, toes
Limited mobility Which directions? movement in only 1 direction (like a door  opened or closed)

20. Types of Movable Joints
3. pivot
In which direction(s) does it move?
twists/rotates
like a door knob
What are examples?
skull w/ vertebrae (neck), lower arm
Examples where skull connects to vertebrae/spine, where ulna & radius (lower arm) connect near elbow
limited mobility Which directions? The end of one bone rotates (pivots) on another

21. Types of Movable Joints
4. gliding
In which direction(s) does it move?
slides back-forth, side-side
What are examples?
vertebrae (spine/back), wrist, ankle
Examples vertebrae, wrist, ankle
limited mobility Which directions? back and forth motion, side to side

22. The Muscular System In Vertebrates
What is a muscle?
tissue that can change shape & length
What is the muscular system?
all muscles in the body
What is the function of the muscular system?
movement
by contraction
>600 muscles human body
made of long, excitable cells capable of contraction
attached to skeleton
contract  pull on skeleton results in movement

23. 3 Vertebrate Muscles Types
What are the 3 different muscle types in vertebrates?
smooth
cardiac
skeletal (striated)
Each has a different structure, pattern, job, location in body
Skeletal muscles (striated) – voluntary, moves bones, long multinucleate cells “fibers”
Smooth muscles – involuntary, lines digestive and respiratory tracts and blood vessels, tapered distinct cells
Cardiac muscle – involuntary, only in heart, striated and branched

24. 3 Vertebrate Muscles Types
1. smooth
What do the cells look like?
tapered (thin ends, thick center)
no stripes (no striations)
Where are they typically found?
digestive tract (for peristalsis), respiratory tract, blood vessels, other organs
What is their function?
regulate activity of organs or vessels
Are their movements voluntary or involuntary?
involuntary
Appearance of cells? tapered distinct cells each w/ nucleus
Where typically found? lines digestive tract, respiratory tract, & blood vessels NOT connected to bone
Function
Used for locomotion? no
Use for peristalsis? Yes Regulate activity of organs or diameter or vessels
Involved in reflex arc? yes
Voluntary or involuntary? involuntary
Contracts quickly or slowly? slowly
Stays contracted for a long or short period? long

25. 3 Vertebrate Muscles Types
2. cardiac
What do the cells look like?
long fibers that branch & weave together
dark & light stripes (striations)
Where are they typically found?
ONLY in heart
What is their function?
contracts rhythmically pump blood out of heart
Are their movements voluntary or involuntary?
involuntary
Appearance of cells? Striated & branched
Where typically found? Only in heart NOT connected to bone
Function contracts rhythmically to force blood out of heart chambers into arteries
Used for locomotion? no
Use for peristalsis? no
Involved in reflex arc? no
Voluntary or involuntary? involuntary
Contracts quickly or slowly? quick
Stays contracted for a long or short period? short

26. 3 Vertebrate Muscles Types
3. skeletal (striated)
What do the cells look like?
long fibers
dark & light stripes (striations)
Where are they typically found?
most of the body
attached to skeleton
What is their function?
move bones of skeleton by contracting
Are their movements voluntary or involuntary?
voluntary
Appearance of cells? long multinucleate striated/striped cells “fibers”
Where typically found? Legs/arms
Function
Used for locomotion? Yes moves bones (locomotion)
Use for peristalsis? no
Involved in reflex arc? Yes
Voluntary or involuntary? Voluntary
Contracts quickly or slowly? quickly
Stays contracted for a long or short period? short

27. Skeletal muscles (striated) – voluntary, moves bones, long multinucleate cells “fibers”
Smooth muscles – involuntary, lines digestive and respiratory tracts and blood vessels, tapered distinct cells
Cardiac muscle – involuntary, only in heart, striated and branched

28. Tendons What are tendons? connective tissue: holds muscles to bones
must be attached to bones at 2 points
at opposite ends of the muscle
What holds muscles to bones? connective tissue called tendons
Attachment to 2 sites is necessary for movement (during contraction one end of the muscle the bone to which it is attached do not move = point of origin) (other end of the muscle & the bone to which it is attached move when the muscle contracts = point of insertion)
The Achilles tendon is the thickest and strongest tendon in the human body

29. Muscle Structure Muscle fibers made of fibrils
made of protein filaments
called actin (thin) & myosin (thick)
Nerve cell + muscle fiber = motor unit

30. How Muscles Work How do muscles work?
by contracting or relaxing (fibers can’t lengthen)
Sliding Filament Hypothesis
muscle receives nerve impulse
actin & myosin slide over one another
muscle contracts
Muscle fibers are made of fibrils which are made of protein filaments called actin (thin) & myosin (thick)
Sliding Filament Hypothesis  muscle receives nerve impulse… actin & myosin slide over one another… muscle contracts… when muscle relaxes actin & myosin go back to original positions

31. How Muscles Work
Since muscles can only contract (or relax), skeletal must work in opposing pairs to allow movement.
flexors
extensors
Muscle fibers are made of fibrils which are made of protein filaments called actin (thin) & myosin (thick)
Sliding Filament Hypothesis  muscle receives nerve impulse… actin & myosin slide over one another… muscle contracts… when muscle relaxes actin & myosin go back to original positions

32. Muscles Work in Pairs What does a flexor do when it contracts?
bends the joint (decreases angle)
Examples of flexors?
biceps, hamstring (back of thigh)
Animation of Muscles Working in Pairs
Muscles Contracting in Pairs
flexor
extensor
What does each do?
flexor causes flexing/decrease of angle (bending) at a joint ex. biceps, hamstring
extensor causes the extension/increase of angle (straightening) of a joint ex. triceps, quadriceps
Flexors & extensors are also important for support of body b/c both muscles of pair are always slightly contracted (“muscle tone”), keeps muscles ready for quick contractions.

33. Muscles Work in Pairs What does an extensor do when it contracts?
straightens the joint (increases angle)
Examples of extensors?
triceps, quadriceps (front of thigh)
Animation of Muscles Working in Pairs
Muscles Contracting in Pairs
flexor
extensor
What does each do?
flexor causes flexing/decrease of angle (bending) at a joint ex. biceps, hamstring
extensor causes the extension/increase of angle (straightening) of a joint ex. triceps, quadriceps
Flexors & extensors are also important for support of body b/c both muscles of pair are always slightly contracted (“muscle tone”), keeps muscles ready for quick contractions.

34. Muscles in Arthropods muscles attached to inside of exoskeleton
also work in opposing pairs

35. Voluntary or involuntary? Muscle Types in the Body
Striated (skeletal)
Cardiac
Smooth
Appearance of cells?
Striped (striated)
Striped (striated) & branched
Tapered
(thin ends, thick center);
no stripes (not striated)
Where typically found?
Attached to skeleton (ex. legs/ arms)
heart
digestive system, respiratory system, blood vessels
Function?
movement
pump blood from heart to arteries
peristalsis, regulate activity of organs or diameter or vessels
Voluntary or involuntary?
voluntary
involuntary
Muscle Types in the Body

36. Questions to Ponder More Review
How do skeletal & muscular systems show unity within diversity?
How does form follow function?
More Review
Joints of the Skeletal System Interactive Table
More Joints of the Skeletal System Interactive Table
Muscle & Connective Tissue Animation