Download Chapter 13 - Roslyn Public Schools

Support and Locomotion
Topic 15
I. Locomotion
A. locomotion - ability of an organism
to move from one place to another
B. advantages
1.
 2.
 3.
 4.
 5.

Obtain food
Find shelter
Move away from toxic materials
Escape predators
Ability to find a mate

C. Adaptations in animals and
protozoans

1. Protozoans - paramecium have cilia,
ameba have pseudopods, euglena have
flagella
Ameba
Paramecium

2. Hydra - sessile – don’t really move –
sort of flip through the water

3. Earthworm - setae - tiny hairs used
to grip soil along with muscle
contractions – hydrostatic skeleton
contains two sets of muscles that can
act independently of each other
Earthworm

4. Grasshopper - jointed appendages
(legs) and wings – has a skeleton on
the outside called an exoskeleton –
made of chitin – periodic molting allows
them to increase in size
Grasshopper
II. Human Locomotion
A. bones – endoskeleton
1. Support and protection
 2. Points of attachment for muscles
 3. Levers for movement
 4. Production of blood cells inside the
bone marrow
 5. two types of cells

• (a) osteoblasts – create new bone
• (b) osteoclasts – reabsorb bone
Human Skeleton

6. two types of bone
• (a) spongy bone – located in the central
portions of the bone – consists of a network
of hard spicules separated by marrow-filled
spaces
• (b) compact bone – located on the outside
surfaces – responsible for the hardness of
the bone
(7) Haversian canal – contains
capillaries
 (8) axial skeleton – skull, vertebral
column, and rib cage
 (9) appendicular skeleton – bones of
the appendages and the pectoral and
pelvic girdles

Bone – haversian canal

B. cartilage - flexible, fibrous, and
elastic tissue
1. Support of structures
 2. Flexibility
 3. Cushioning

Cartilage

C. muscles

1. three types
• a. Skeletal - striated – voluntary – have overlapping
filaments called actin and myosin which are
organized into sections called sarcomeres
• b. Smooth - not striated – involuntary – found in
visceral systems (digestive, urinary, uterus) and the
nervous systems – found in arteries and veins –
cells are connected directly to each other – no
spaces
• c. Cardiac - heart - involuntary – striated – have a
single nucleus – has an internal pacemaker for the
heartbeat
Cardiac Muscle
Cardiac muscle
Skeletal Muscle
Skeletal Muscle
Smooth muscle
Smooth muscle

D. Muscle Movement
 1. sliding-filament model
• a. a sarcomere shortens or thickens when the thin
filaments (actin) slide across its thick filaments (myosin)
• b. in a contracting sarcomere, the z lines and the thin
filaments (actin) have moved toward the middle of the
sarcomere
• c. in a fully contracted muscle, the thin filaments (actin)
overlap in the middle of the sarcomere
• d. contraction only shortens the sarcomere; it does not
change the lengths of the thick and thin filaments

2. How does the sliding work:
• a. ATP binds to a myosin head which is
released from an actin filament
• b. energy is available for contraction when
ATP is converted to ADP – the myosin head
is then cocked
• c. the myosin head attaches to the actin
binding site
• d. the actin filament slides toward the
center of the sarcomere
Actin and Myosin

E. tendons and ligaments
1. Tendons - attach muscle to bones
 2. Ligaments - attach bone to bone

Bones, Ligaments, Cartilage
F. Joints

G. malfunctions
1. Arthritis - pain in the joints
 2. Tendonitis - inflammation of a
tendon
