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

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 Neurotransmitters released from here

Circulatory System Transports O 2, CO 2, and nutrients around the body Arteries (carry blood away from the heart) Veins (carry blood towards the heart) Capillaries (where nutrients and O 2 diffuse into your body tissues and cells)

Blood Cells and Platelets Red Blood Cells - transports O 2 and CO 2 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

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 lungs 3. from lungs 1.O 2 poor blood from body 1.O 2 poor blood from body 4. O 2 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 CO 2 - (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))

Esophagus muscular tube through which food and drink travel to the stomach Stomach food is mixed with enzymes and acids Small intestine- nutrients absorbed into bloodstream Large intestine- Undigested food is eliminated in feces Liver removes wastes from the blood and produces bile to help digest fats Gallbladder stores bile and sends it 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