skeletal system functions support protection of organs framework for movement calcium storage blood...

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

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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)





Functions of skeletal muscle

• Movement of the skeleton

• Maintaining Posture

• Stabilize joints

• Generate heat

Anatomy of a Skeletal Muscle

fascicle



Sarcomere: Made of actin and myosin proteins

(fiber)

Muscle

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



Control of muscle contraction

• Nerve cells called motor neurons signal muscles to contract at our command



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)

Communication between nerve cells

• Neurons (nerve cells) communicate with each other using electrical signals called action potentials (nerve impulses) and chemical messengers called neurotransmitters



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



Neurotransmittersreleased 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


are needed to see this picture.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



Path of Blood Through the Heart



2. To lungs2. To lungs

3. from lungs3. from lungs

1. O2 poor bloodfrom body

1. O2 poor bloodfrom body

4. O2 rich blood (to body)

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)



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))



Esophagusmuscular tube throughwhich food and drinktravel to the stomach

Stomachfood is mixed withenzymes and acids

Small intestine-nutrients absorbed intobloodstream

Large intestine-Undigested food is eliminated in feces

Liverremoves wastesfrom the blood and produces bile to helpdigest fats

Gallbladderstores bile and sendsit to small intestine



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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