Search Results

Conduction of action potentials

By: HWC, Views: 7947

• Action potentials must be rapidly conducted over long distances in order for the nervous system to communicate with other cells. • Propagation of an action potential uses processes similar to those that generate the potential at the trigger zone. • a When a graded potential reaches ...

Factors that affect conduction rates (myelination, axon diameter & temperature)

By: HWC, Views: 7931

• Several factors determine the rate of conduction of action potentials: • Myelination • Axon diameter • Temperature • The step-by-step depolarization of an axon is called continuous conduction and occurs along unmyelinated axons. • Neurons in the PNS have many axons that ...

Types of synapses - electrical & chemical

By: HWC, Views: 7894

• Neurons communicate with one another or effector cells via synapses that allow information to be filtered and integrated. • The two types of synapses are: • electrical • chemical. • Electrical synapses, also known as gap junctions, contain many ion channels (connexons) conne...

Neurotransmission at chemical synapses & Excitory and inhibitory potentials

By: HWC, Views: 7718

• A series of events occur at chemical synapses in order to communicate with the adjacent cell. • The action potential arrives at the presynaptic membrane. • The depolarization phase of the action potential opens voltage gated Ca+ channels. • increased inflow of Ca+' into the cyto...

Summation - defined, spatial, temporal & AP generation or not

By: HWC, Views: 7707

If several presynaptic end bulbs release their neurotransmitter at about the same time, the combined effect may generate a nerve impulse due to summation Summation may be spatial or temporal • A typical neuron may have thousands of synapses. A corresponding number of postsynaptic membrane ...

Hormonal feedback loop components & Glucagon (glycogenolysis and gluconeogenesis)

By: HWC, Views: 7597

The endocrine system maintains many body conditions within normal limits with feedback loops. Each endocrine feedback loop maintains homeostasis using the following components: • Stimulus - a change in a body condition. • Production cell - an endocrine cell that produces a hormone after ...

ACTH/Cortisol (glycogenolysis, protein catabolism, lipolysis and gluconeogenesis)

By: HWC, Views: 7645

• A decline in blood glucose concentration stimulates corticotropic cells in the anterior pituitary to produce adrenocorticotropic hormone (ACTH). • ACTH binds with cells in the zona fasciculata of the adrenal cortex. • Increased ACTH promotes the production of cortisol, the major gluco...

Insulin (glucose uptake by body cells), glycogenesis and lipogenesis

By: HWC, Views: 7902

Insulin is the regulator that allows the sugar from the foods we eat (be it a piece of cake or a stick of celery) to enter our tissues and become part of the metabolic process. Insulin is made by the Islets of Langerhans, which are found in the pancreas of every person. As we previously mentio...

Parathyroid hormone (bone resorption) & Calcitonin (bone deposition)

By: HWC, Views: 7754

• Cellular needs for calcium may cause blood calcium concentrations to decline below the normal range. • This decrease stimulates cells in the parathyroid gland to secrete parathyroid hormone. • Binding of parathyroid hormone to osteoclasts in bone tissue promotes bone resorption and th...