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Stimulus (introduction)

By: HWC, Views: 6318

• Blood pressure determines the flow of blood to and from capillaries. • Low blood pressure results in reduced blood flow. • High blood pressure can cause blood vessels to break. In humans, sensitivity is due to portions of the nervous system called receptors. Receptors are typicall...

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

By: HWC, Views: 6736

■ 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 ...

Regulation of GFR: autoregulation via myogenic mechanism Myogenic mechanism

By: HWC, Views: 8128

• GFR can be regulated by adjusting: • Blood flow in and out of the glomerular capillaries. • Surface area of glomerular capillaries. • There are three main ways to make these adjustments: • Renal autoregulation. • Nervous regulation. • Renal autoregulation occurs when...

Regulation of GFR: autoregulation via tubuloglomerular feedback, neural & hormonal regulation

By: HWC, Views: 7809

• When blood pressure is above normal, rapid filtrate flow reduces ion retention so filtrate in tubule has more Na+, C1-, and water. • It is believed that vasoconstricting chemicals from the juxtaglomerular cells are released when the macula densa cells detect higher water and ion levels in ...

Bulk flow - Factors that influence bulk flow

By: HWC, Views: 6885

• Bulk flow helps regulate the relative volumes of blood and interstitial fluid. • Flow from blood to interstitium is called filtration. ■ Flow from interstitium to blood is called reabsorption. ■ Four factors determine the net direction of capillary exchange. ■ These factors in...

Energy Flow - Trophic Levels and Food

By: HWC, Views: 6211

All of these relationships between different species are founded on one thing: energy. Organisms get food in order to get energy, which is used by the organism for growth, maintaining health, and reproduction. We can classify the members of a community according to how they obtain food. Produc...

Negative Feedback Regulation of Blood Pressure

By: HWC, Views: 6646

stimulus • Blood pressure determines the flow of blood to and from capillaries. • Low blood pressure results in reduced blood flow. • High blood pressure can cause blood vessels to break. Baroreceptors • The aortic arch carries blood to the body. • The common carotids ca...

Pressure Flow Model Animation

By: HWC, Views: 5849

This apparatus of beakers A and funnels simulates the flow of a sucrose solution in the phloem of a plant. The funnels and connecting tube represent a sieve tube of the phloem. Differentially permeable membranes cap the funnels at the source and sink ends, allowing water, but not sucrose, to cros...

The Pressure Flow Model in a Plant

By: HWC, Views: 6015

The vascular system of plants has two transport tissues, called xylem and phloem. Xylem transports water and minerals, while phloem transports a variety of dissolved substances, including sugars and amino acids, throughout the plant. Water in the xylem always moves up, in the direction from th...