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Structures that affect circulation - arterioles and vasomotor responses and venous return

By: HWC, Views: 7807

■ Small arteries and arterioles determine SVR. • Blood pressure drops significantly as blood passes through arterioles. • Decreasing arteriole radius and decreased wall elasticity are the main reasons for increased SVR. ■ Small changes in arteriole radius can cause large changes in ...

Muscle Twitch and Muscle Tension - Motor unit size and force

By: HWC, Views: 7981

• A motor unit is a group of muscle cells controlled by a single neuron. • A stimulus of sufficient intensity will cause all the cells in the motor unit to contract. • A single contraction, caused by a single action potential, is called a muscle twitch. • Latent period: A brief per...

Neural Reflex Arc Animation

By: Administrator, Views: 10945

A reflex arc is a neural pathway that controls a reflex. In vertebrates, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the bra...

Structures of the Eye Animation

By: Administrator, Views: 2092

Orbit A cone-shaped cavity in the front of the skull that contains the eyeball. Formed by the combination of several bones and is lined with fatty tissue that cushions the eyeball. This cavity has several foramina (openings) through which blood vessels and nerves pass. Largest opening is the ...

Muscle cell structures - actin, myosin and titin filaments

By: HWC, Views: 7892

Once the muscle cell has been excited it will contract. • A muscle action potential will trigger the release Of Ca2+ ions into the sarcoplasm. • The Ca2+ ions bind to the regulatory proteins and trigger contraction. • Within skeletal muscle cells are structures that provide the ability...

Shoulder Movement Animation

By: Administrator, Views: 686

Four muscles—the supraspinatus, infraspinatus, teres minor, and subscapularis—make up the rotator cuff. It stabilizes the shoulder and holds the head of the humerus into the glenoid cavity to maintain the principal shoulder joint.

Bone Healing Animation

By: Administrator, Views: 10729

A visual on how bones eventually heal themselves. Traction is the application of a pulling force to maintain bone alignment during fracture healing. Different fractures require different types of traction. (A) Balanced suspension traction is commonly used for fractures of the femur. (B) Skelet...

Cardiac Cycle (Part 1 of 4)

By: Administrator, Views: 10769

Blood Flow through the atrium.

TRH/TSH/Thyroid hormone

By: HWC, Views: 7270

Thyroid hormone production • A decline in metabolic rate caused by increased metabolic need or physical exertion stimulates the production of thyrotropin hormone releasing (TRH) hormone from the cells of the hypothalamus. • Thyrotropin hormone releasing hormone targets the thyrotrophic ce...