Transcript Skeletal System Functions

Skeletal System Functions
• Support
• Protection of organs
• Framework for
movement
• Calcium storage
• Blood cell production
(bone marrow)
Axial vs. Appendicular Skeleton
Axial:
• Skull, rib cage,
vertebrae
Appendicular:
• Arms and legs
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Connective tissue and
cartilage
• Tendons - attach muscles to bones
(muscles pull on bones to create
movement)
• Ligaments - connect bones to other
bones at joints
• Cartilage - provides cushioning and
lubrication at joints
*all three are found at most joints (area where two or
more bones meet)
Types of muscle
• Skeletal muscle
• Cardiac (heart)
• Smooth (blood
vessels and organs
(ex. stomach)
* only skeletal is
voluntary (we have
conscious control
over it)
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Functions of skeletal
muscle
• Movement of the
•
•
•
skeleton
Maintaining
Posture
Stabilize joints
Generate heat
Anatomy of a Skeletal Muscle
Muscle
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(fiber)
fascicle
Sarcomere: Made of actin
and myosin proteins
Actin and Myosin
• Actin and myosin are
•
•
proteins that cause
muscles to contract
Myosin attaches to
actin and pulls on it to
cause a muscle
contraction
Form the sarcomere
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Control of muscle contraction
• Nerve cells called
motor neurons signal
muscles to contract at
our command
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Nervous System
FUNCTION: Allows for all parts of the body to
communicate with the brain and spinal chord so we
can sense our environment
• Central Nervous System - made of the brain and
spinal chord
• Peripheral Nervous System - all nerve cells outside
of the CNS (2 types of nerve cells):
 sensory neurons - for your sense of sight, touch, hearing,
tasting, etc.
 motor neurons (for controlling movement of your muscles
and control of other organs and glands)
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Communication between
nerve cells
• Neurons (nerve cells)
communicate with each
other using electrical
signals called action
potentials (nerve
impulses) and chemical
messengers called
neurotransmitters
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Structure of a Neuron (a nerve cell)
• Axon - transmits nerve
•
•
•
•
impulses to communicate with
other cells and organs
Dendrites - receive signals
from other neurons
Myelin sheath - fatty coating
on axon that speeds up
impulses
Neurotransmitters chemicals released from one
neuron that allow signals to
pass to other neurons
Axon terminals - end of the
axon where neurotransmitters
are released
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Neurotransmitters
released from here
Circulatory System
• Transports O2, CO2, and nutrients around
the body
• Arteries (carry blood away from the heart)
• Veins (carry blood towards the heart)
• Capillaries (where nutrients and O2 diffuse
into your body tissues and cells)
Blood Cells and Platelets
• Red Blood Cells - transports O2 and
CO2 in the blood
• White Blood Cells - help to defend the
body against foreign invaders and
cancer cells
• Platelets - function in blood clotting
* All are produced in bone marrow
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Veins (blue)
Arteries (red)
capillaries
The Heart
• Consists of 4 chambers
• Pumping chambers are the
ventricles:
- Right ventricle
pumps blood to lungs
- Left vent. pumps
blood to rest of body
• Receiving chambers are the atria
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Path of Blood Through the Heart
1. O2 poor blood
from body
4. O2 rich blood (to body)
2. To lungs
2. To lungs
3. from lungs
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1. O2 poor blood
from body
3. from lungs
Coronary Blood Vessels
• Coronary arteries
•
supply heart muscle
with oxygen and
nutrients
Heart attacks occur
when a blockage
occurs in a coronary
artery
Respiratory System
FUNCTION: To take in oxygen and
exchange it for carbon dioxide.
• Larynx - contains vocal chords
• Trachea - “windpipe”; air passes
through this tube on way to the lungs
• Bronchi - branches of trachea going
to each lung
• Bronchioles - smaller branches of the
bronchi
• Alveoli - air sacs surrounded by
capillaries where oxygen is exchanged
for CO2 - (blood returns to heart from
here)
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Digestive System and
Excretory System
FUNCTION: Breakdown food molecules so that
they can be absorbed into the bloodstream AND
elimination of wastes
• Mechanical digestion - physical breakdown of
food (chewing, churning of the stomach)
• Chemical digestion - breakdown of food by
enzymes (occurs in saliva, stomach, and small
intestines)
• Elimination of wastes (large intestine (feces),
liver and kidneys (remove wastes from blood))
Liver
removes wastes
from the blood and
produces bile to help
digest fats
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Gallbladder
stores bile and sends
it to small intestine
Large intestineUndigested food is
eliminated in feces
Esophagus
muscular tube through
which food and drink
travel to the stomach
Stomach
food is mixed with
enzymes and acids
Small intestinenutrients absorbed into
bloodstream
Urinary System
• Kidneys filter toxins
•
•
out of the blood and
produce urine
Each kidney contains
small filtering units
called nephrons
There are 1 million
nephrons per kidney
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