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Action potentials - electrical characteristics and generation

By: HWC, Views: 6579

• 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...

Second Messengers in the Inositol-lipid Signaling Pathway

By: HWC, Views: 5886

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...

ATPase function - membrane transport, contractile proteins and synthesis

By: HWC, Views: 7042

• 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...

What Are Carbohydrates? Importance of Carbs & High Carb Food

By: HWC, Views: 6712

We hear a lot about carbohydrates in the news. Everybody seems to be on a low-carb diet. The news media often has stories on this diet fad, and companies are busy producing products with reduced carbohydrates. What's this fascination with carbohydrates? In a word: "Diet." The fact is that carb...

Digestive System Animation

By: Administrator, Views: 9909

Digestive system contains both primary and accessory organs for the conversion of food and fluids into a semiliquid that can be absorbed for the body to use. Three main functions: - Digestion - Absorption - Elimination With aging: - Digestive system becomes less motile. - Glandular sec...

Neurosynapse Animation

By: Administrator, Views: 9622

In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. Synapses are essential to neuronal function: neurons are cells that are specialized to pass signals to individual tar...

Lymphatic System Animation

By: Administrator, Views: 446

Blood and lymph are two of the body's main fluids and are circulated through two separate but interconnected vessel systems. Blood is circulated by the action of the heart, through the circulatory system consisting largely of arteries, veins, and capillaries. Lymph does not actually circulate. ...

Urinary System Animation

By: Administrator, Views: 875

The urinary system: kidneys, ureters, bladder, and urethra with expanded view of a nephron and the urine-filled space within a bladder. Urinary system: two kidneys, two ureters, one bladder, one urethra. Also called the excretory, genitourinary (GU), or urogenital (UG) system. Produces, stor...

Chloroplast Structure & Light Dependent Reactions (Photosystem 1 and 2 Cyclic Electron Flow)

By: HWC, Views: 6291

The leaf is the principle photosynthetic organ of the plant. This is a cross section of a leaf. The rectangular-shaped cells are part of the photosynthetic tissue called the palisade mesophyll. Each photosynthetic cell can contain several hundred organelles known as chloroplasts. The chlorop...