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Neurotransmission at chemical synapses & Excitory and inhibitory potentials

By: HWC, Views: 6559

• 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...

Phases of an Action Potential - Resting Potential, Threshold, Rising, Falling, & Recovery Phases

By: HWC, Views: 6085

In this tutorial, we will review the phases of an action potential measured from a small area of a neuron's membrane. The action potential can be divided into five phases: the resting potential, threshold, the rising phase, the falling phase, and the recovery phase. When the neuron is at rest,...

Uterine (menstrual) cycle - phases

By: HWC, Views: 6665

• The uterus goes through a cyclical developmental pattern to be ready for implantation and support of an embryo. • The uterine, or menstrual, cycle is under the control of ovarian horrnones. • The uterine cycle also has three phases: • Menstrual phase • Proliferative phase â€...

Summary of female reproductive cycle days 1-28

By: HWC, Views: 7075

â–  The first five days of the cycle include the menstrual phase. â–  Progesterone and estrogen levels are low. â–  Menses occurs. â–  GnRH pulses more frequently promoting FSH and LH levels to rise. â–  Primary follicles are stimulated to develop. â–  Days five through thirteen consist o...

Electrical changes in the heart

By: HWC, Views: 6476

• ECG: Graph of the voltage changes that occur during the cardiac cycle. • Readings are taken by electrodes placed on the surface of the body. • Electrodes detect voltage changes caused by the electrical activity of the heart. • P wave = atrial excitation (atrial depolarization). ...

Action potentials - electrical characteristics and generation

By: HWC, Views: 6563

• 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...

Depolarization of the SA node, Action potentials of the myocardium & ANS effects

By: HWC, Views: 6500

• A typical contractile cell in the myocardium has a resting membrane potential. • The resting membrane potential of cells in the SA node is not fixed, and is known as the pacemaker potential. • The action potential of a healthy SA nodal cell has three parts: • Pacemaker potential: ...

Phases of the ovarian cycle

By: HWC, Views: 7017

• The ovarian cycle is a monthly sequence of events, consisting of three phases: • Preovulatory • Ovulatory • Post ovulatory Preovulatory phase • prior to ovulation: Primary follicles develop into secondary follicles. • Follicular cells surrounding the primary oocyte In...

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

By: HWC, Views: 6536

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 ...