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Gastrin (protein digestion)

By: HWC, Views: 6654

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 b...

Chemical Synapse Animation

By: HWC, Views: 4015

A neuromuscular junction is a chemical synapse between the axon endings of a motor neuron and a muscle cell. A narrow synaptic cleft separates the presynaptic cell (the motor neuron) from the postsynaptic cell (the muscle cell). The presynaptic cell contains vesicles filled with neurotransmitt...

Endocytosis - pinocytosis, receptor mediated and Transcytosis

By: HWC, Views: 6584

Pinocytosis is the process in which a cell "drinks" a tiny droplet Of extracellular fluid, including its solutes. Pinocytosis (Cell Drinking) is the process by which the cell takes in fluids (as well as any small molecules dissolved in those fluids). • The plasma membrane folds inward to...

Plant Defense Mechanisms from Pathogens

By: HWC, Views: 6105

Plants and pathogens have coevolved such that pathogens can recognize plants by the sugars, or other molecules, they produce. Plants, in turn, can recognize pathogens by the molecules they produce. The ability to recognize pathogens allows plants to activate defense systems that can prevent wides...

Stomach peristalsis & Enterogastric reflex

By: HWC, Views: 6076

• Food enters, distending the stomach. • Stretch receptors activate enteric reflexes that promote peristaltic movements. • These movements, called mixing waves, begin to mix the food with stomach secretions. • Mixing waves force the digesting food (chyme) toward and through the pylo...

Olfaction. or the sense of smell

By: HWC, Views: 4035

Do you ever wonder how you can distinguish thousands of different odors? Olfaction. or the sense of smell, is used by all mammals to navigate, find food, and even find mates. We have millions of olfactory receptors for smelling in our nose. These receptor neurons bind water-soluble or volatil...

Nervous pathway to the Neuromuscular (NMJ)

By: HWC, Views: 7184

• A nervous impulse, also called an action potential, starts from the brain or spinal cord to signal skeletal muscle cell contraction. Action potentials continue along a motor neuron to the muscle cell. • The signal to contract must cross a synapse - the neuromuscular junction (NMJ) - betwe...

Stimulus (introduction)

By: HWC, Views: 6327

• 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...

Stretch reflex & Tendon reflex

By: HWC, Views: 6389

• The stretch reflex is a response to the stretching of muscles. It is monosynaptic and ipsilateral. • Stretching stimulates receptors in the muscle spindle of the agonist (stretched) muscle. • One or more action potentials are generated by the receptors and propagate along the axon of ...