Study Guide: Exam 3 – Spring 2026

These flashcards cover key terms and concepts relevant to the exam, focusing on sensory systems, hormonal regulation, homeostasis, and biological rhythms.

Sensation

The process by which sensory receptors and the nervous system receive and represent stimulus energies from our environment.

Perception

The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.

Transduction

The conversion of one form of energy into another; in sensation, the transforming of stimulus energies into neural impulses.

Pacinian corpuscles

Type of mechanoreceptor sensitive to vibration and pressure located deep in the skin.

Merkel’s discs

Type of mechanoreceptor that responds to light touch, located near the surface of the skin.

Dorsal column pathway

A neural pathway that conveys fine touch and proprioception information from the body to the brain.

Somatosensory cortex (S1)

The region of the brain that processes sensory information from the body, located in the postcentral gyrus.

Sensory adaptation

The process by which sensitivity to prolonged stimulation tends to decline over time.

Tonic activation

The persistent activation of sensory receptors for a prolonged period.

Phasic activation

The rapid responses of sensory receptors to changes in stimulation.

Receptive fields

The specific area of sensory input that influences the activity of a particular neuron.

TRPV1

A receptor sensitive to heat and pain, activated by temperatures and capsaicin.

Aδ fibers

Myelinated nerve fibers that transmit sharp, localized pain signals quickly.

C fibers

Unmyelinated nerve fibers that transmit dull, burning pain signals slowly.

Periaqueductal gray (PAG)

A midbrain structure involved in pain modulation, releasing endorphins.

Spinothalamic projections

A neural pathway for pain and temperature sensations that transmits information to the brain.

Placebo effect

A beneficial effect produced by a placebo drug or treatment, resulting from the patient's expectations.

Homunculus

A visual representation of the body parts in the brain corresponding to sensory areas, showing the distribution of sensory input.

Photoreceptors

Cells in the retina that convert light into neural signals; includes rods and cones.

Fovea

The central region of the retina where visual acuity is highest due to a high concentration of cones.

Rods

Photoreceptors responsible for vision in low-light conditions.

Cones

Photoreceptors responsible for color vision and visual acuity in bright light conditions.

Lateral geniculate nucleus (LGN)

A thalamic relay center for visual processing that receives input from the retina.

Bipolar cells

Neurons in the retina that transmit signals from photoreceptors to ganglion cells.

Ganglion cells

Neurons that send visual information from the retina to the brain via the optic nerve.

Lateral inhibition

The process by which stimulated neurons inhibit the activity of neighboring neurons, enhancing contrast.

Ventral path

The 'what' pathway of visual processing, involved in object recognition.

Dorsal path

The 'where' pathway of visual processing, involved in spatial awareness.

Hypothalamic-pituitary axis

The interaction between the hypothalamus and pituitary gland that regulates hormone release.

Releasing hormones

Hormones that stimulate the release of other hormones from the anterior pituitary.

Osmotic thirst

A type of thirst triggered by high osmotic pressure due to water loss.

Hypovolemic thirst

A type of thirst triggered by a loss of blood volume.

Vasopressin (ADH)

A hormone that promotes water retention by reducing urine output.

Negative feedback

A mechanism in which a deviation from a set point triggers responses that reverse the deviation.

Circadian rhythms

Biological cycles that occur approximately every 24 hours, regulated by the suprachiasmatic nucleus.

Zeitgeber

External cues, like light, that help synchronize biological rhythms.

Melatonin

A hormone produced by the pineal gland that regulates sleep-wake cycles.

Cortisol

A hormone that follows a daily rhythm, peaking in the morning and regulating metabolism.