Search results for: 'Timing of contraction signal'

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By: Administrator, Views: 9931

Process of Hearing Sound waves are directed to the eardrum, causing it to vibrate. These vibrations move the three small bones of the middle ear (malleus, incus, and stapes). Movement of stapes at oval window sets up pressure waves in the perilymph and endolymph. Process of Hearing The wav...

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Structures that affect circulation - kidneys, blood volume and venous tone

By: HWC, Views: 6649

• Kidneys regulate blood volume and blood osmolarity via salt and water reabsorption. • Increased reabsorption increases blood volume and venous return (and CO). • Decreased reabsorption increases urine production, which decreases blood volume and venous return (and CO). • Systemi...

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Blood Flow through the Human Heart

By: HWC, Views: 6436

The heart is the pump of the human circulatory system. The left side of the heart has two connected chambers, the left atrium and the left ventricle. The right side of the heart also has two connected chambers, the right atrium and the right ventricle. These two sides, or pumps, of the heart are ...

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Second Messengers in the Inositol-lipid Signaling Pathway

By: HWC, Views: 5901

Extracellular signals produce specific responses in target cells through the action of intracellular second messengers. Here, we focus on three second messengers, IP3, DAG, and Ca2+, all involved in the inositol-lipid signaling pathway. A hormone-receptor signal on the cell surface leads to the a...

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Neural Reflex Arc Animation

By: Administrator, Views: 9842

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...

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ATPase function - membrane transport, contractile proteins and synthesis

By: HWC, Views: 7055

• Energy from ATP is used to move ions across the cell membrane during active transport. • This membrane protein transports sodium out of the cell and potassium into the cell. As such, it is called a sodium-potassium pump. • Because this pump also acts as an enzyme to hydrolyze ATP it i...

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Action potentials - electrical characteristics and generation

By: HWC, Views: 6589

• An action potential is the nervous impulse or signal for long distance communication. Each action potential is generated at the cell's trigger zone. • Action potentials are considered an all-or-nothing phenomena because they are either generated or not. • The generation of an action...

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Helper T cell receptors, activation, proliferation, differentiation & action

By: HWC, Views: 6771

• Most cells which have CD4 on their surface become Helper T cells (TN cells). • The CD4 1 cells only recognize a foreign antigen when it is presented with an antigen presenting immune cell (APC) that includes MHC-II protein. • The Helper T cell antigen receptor must match the presented...

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Status Epilepticus

By: Administrator, Views: 9653

Status epilepticus (SE) is a single epileptic seizure lasting more than five minutes or two or more seizures within a five-minute period without the person returning to normal between them. Previous definitions used a 30-minute time limit. The seizures can be of the tonic–clonic type, with a re...

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