Download CANLILARDA HAREKET VE İSKELET SİSTEMİ

Movement and skeletal
system
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All organisms move to find food, escape from
predators, migrate, protect their habitat. Plant
movement is different than the other organisms
because they anchor to soil with their roots.
Skeletal and muscular system help movement.
Skeleton gives shape to the organisms.
Exoskeleton covers the body of the
organism(insects, molluscs) Endoskeleton is
found inside of the body. (mammal, birds)
Support and movement in plants
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Supportive tissues and turgor pressure give the main
support to the body of the plants.
Turgor pressure is the pressure against cell wall of the
plant cell. If Turgor pressure decreases the support will
be less.
Supportive tissues (collenchyma-living, and
sclerenchyma-nonliving) with thickened cell walls help
plant body.
Also vascular tissues help support.
Plants move with nastic movements and
tropisms as we mentioned before.
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Skeletal (Support) system in Animals
In one celled organisms SiO2, CaCO3 fibrils help
support. They move with cilia, flagella or by
pseudopods.
Exoskeleton:Covers the body of the animal.
Contains many organic (chitin- a polysaccharide) and
inorganic molecules(CaCO3). Muscles are fixed to
the inner surface of the exoskeleton. Exoskeleton
prevents growth, so animals with exoskeleton should
break up their skeleton and form a new skeleton for
growth(molting). Also exoskeleton prevents water
loss.
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Hydrostatic exoskeleton- consists of a volume
of fluid enclosed in a body cavity surrounded by
muscle.of cnidarians, annelids, and many other
soft-bodied invertebrates.
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In Endoskeleton muscles are attached to them
and with joints endoskeleton helps movement.
Human skeletal system
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There are 206 bones in the human skeleton. It is less than the
number of bones in the baby. The skeleton supports the body. The
bones of the lower limbs support the entire body when we are
standing, and the pelvic girdle supports the abdominal cavity.
The skeleton protects soft body parts. The bones of the skull protect
the brain; the rib cage protects the heart and lungs.
The skeleton produces blood cells. All bones in the fetus have red bone
marrow that produces blood cells. In the adult, only certain
bones produce blood cells.
The skeleton stores minerals and fat. All bones have a matrix that
contains calcium phosphate, a source of calcium ions and
phosphate ions in the blood. Fat is stored in yellow bone
marrow.
The skeleton, along with the muscles, permits flexible body movement.
While articulations (joints) occur between all the bones, we
associate body movement in particular with the bones of the
limbs.
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Compact bone, or dense bone, contains many cylinder-shaped
units called osteons. The osteocytes (bone cells) are in tiny
chambers called lacunae that occur between concentric layers of
matrix called lamellae. The matrix contains collagenous protein
fibers and mineral deposits, primarily of calcium and
phosphorus salts. In each osteon, the lamellae and lacunae
surround a single central canal. Blood vessels and nerves from
the periosteum enter the central canal. The osteocytes have
extensions that extend into passageways called canaliculi, and
thereby the osteocytes are connected to each other and to the
central canal.
Spongy bone, or cancellous bone, contains numerous bony bars
and plates, called trabeculae. Although lighter than compact
bone, spongy bone is still designed for strength. Like braces used
for support in buildings, the trabeculae of spongy bone follow
lines of stress.
In infants, red bone marrow, a specialized tissue that produces
blood cells, is found in the cavities of most bones. In adults, red
blood cell formation, called hematopoiesis, occurs in the
spongy bone of the skull, ribs, sternum (breastbone), and
vertebrae, and in the ends of the long bones.
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Bone is made up of solidified extracellular matrix (osein)which
contains protein, Ca, P, MgP, CaCO3,CaFl.
Bones are classified according to their shapes:
 Long: arm, leg
 Short: ankle
 Flat: skull,
 Irregular –vertebrae.
The skeleton is divided into the
axial skeleton and the
appendicular skeleton. The
tissues of the axial and
appendicular skeletons are
bone (both compact and
spongy), cartilage (hyaline,
fibrocartilage, and elastic
cartilage), and dense
connective tissue, a type of
fibrous connective tissue.
Joints: Bones are held together by joints. They
are classified according to their ability to
move.
 Synovial joints: They can freely move . They
have joint cavity which is filled with synovial
fluid and covered with synovial membrane.
Knee joint
 Cartilaginous joints: Slightly moveable joints
in vertebrae, ribs and pubic symphysis. They
contain fibrous cartilage.
 Fibrous joints: Immoveable joints in skull.
MUSCULAR SYSTEM
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All invertebrates contain smooth muscle except
arthropoda.
Arthropoda has skeletal(striated) muscle.
Skeletal muscle
Cardiac muscle
Smooth muscle
Multinucleated at the
periphery
Long fibers
Voluntary-striated
Fast contraction
Rapid fatigue
1 or 2 nuclei at the center
Striated but involuntary
Contain branches in fibers
Intercalated discs between
cells.
Never get tired
1 nucleus at the center
Not striated
Involuntary
Spindle shaped
Slow contraction
Human muscular system, structure
of the muscle and contraction
Smooth muscles are stimulated by autonomous nervous
sytem. They contract with the help of the Ca ions and
hormones.
 Skeletal muscles contract with the information from
brain and spinal cord. The junction between neuron
axon ending with muscle is named as neuromuscular
junction. One neuron can extend to many muscle
fibers.
 Muscles can contract with the stimulation of motor
neurons. To start the contraction, the stimulus should
be at a certain level. All or none law.
Stages of contraction
 Stimulation
of the muscle and start of
contraction –latent period
 Contraction Relaxation- muscle relaxes and waits for new
stimulus.
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http://www.brookscole.com/chemistry_d/templates/student
_resources/shared_resources/animations/muscles/muscles.h
tml
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The plasma membrane of a muscle fiber is
called the sarcolemma; the cytoplasm is the
sarcoplasm; and the endoplasmic reticulum is
the sarcoplasmic reticulum.
The sarcolemma forms T (transverse) tubules
that penetrate into the cell so that they come
into contact—but do not fuse—with expanded
portions of the sarcoplasmic reticulum.
The expanded portions of the sarcoplasmic
reticulum are calcium storage sites.
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The sarcoplasm contains millions of myofibrils. Contractile
portions of muscles.
Myofibrils and Sarcomeres
Myofibrils are cylindrical in shape and run the length of the
muscle fiber. The striations of skeletal muscle fibers are formed
by the placement of myofilaments within units of myofibrils
called sarcomeres. A sarcomere extends between two dark
lines called the Z lines. A sarcomere contains two types of
protein myofilaments. The thick filaments are made up of a
protein called myosin, and the thin filaments are made up of a
protein called actin. Other proteins are also present. The I
band is light colored because it contains only actin filaments
attached to a Z line. The dark regions of the A band contain
overlapping actin and myosin filaments, and its H zone has
only myosin filaments.
The sarcoplasm also contains glycogen, which provides stored
energy for muscle contraction, and the red pigment
myoglobin, which binds oxygen until it is needed for muscle
contraction.
Contraction mechanism
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The muscle fiber contracts as the sarcomeres within the
myofibrils shorten.
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When a sarcomere shortens, the actin (thin) filaments slide on the
myosin (thick) filaments and approach one another.
The movement of actin filaments in relation to myosin filaments is
called the sliding filament theory of muscle contraction
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http://highered.mcgrawhill.com/sites/0072324813/st
udent_view0/chapter12/elearn
ing_connection.html
http://harveyproject.science.w
ayne.edu/development/muscle
/juncti~1.htm
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In the sarcomere, dark band (A) contains myosin and actin myofibrils.
Light band contains (I) contains thin actin myofilaments.
When a sarcomere shortens, the actin (thin) filaments slide on the
myosin (thick) filaments and approach one another. This causes the I
band to shorten and the H zone to almost or completely disappear.
, the sarcomere shortens even though the filaments themselves remain
the same length.
Myosin filaments break down ATP and have crossbridges that pull the
actin filaments toward the center of the sarcomere.
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Axon endings of a neuron contains a special neurotransmitter
called acetylcholine.
When stimulus reaches the axon end, the neurotransmitter is
released to the synaptic cleft.
Acetylcholine binds to receptors on muscle sarcolemma and
forms a impulse in muscle fiber.
Impulse travels down T tubules in sarcolemma, and calcium is
released from the sarcoplasmic reticulum.
Ca binds actin and on the actin myosin binding sites are free to
bind with myosin. Myosin heads with ATP bind with actin
myofilaments. Actin slides over the myosin by
dephosphorylation of ATP. Sarcomere shortens.
Dark band (A band) stays at same length but Light band (I )
and H band shortens.
During relaxation, myosin detaches from the actin by ATP
binding. And Ca ions are collected in Sarcoplasmic reticulum.
Muscle and bone relation
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Muscles are attached to bones by tendons.
Antagonistic muscle pairs work opposite one another to
bring about movement in opposite directions. For example,
the biceps brachii and the triceps brachii are antagonists;
one flexes the forearm, and the other extends the forearm