Final Exam- P261 IUN (lecture)

What are sensory receptors?

Specialized cells, cell processes, or simple organs that monitor specific conditions and respond to stimuli.

What is the role of sensory receptors?

They act as the interface between the CNS and the internal and external environments, functioning as transducers.

What information do sensory receptors transmit?

Modality, location or field, intensity, and duration.

How do nerve fibers respond to stimuli?

Nerve fibers fire when an action potential is generated, regardless of the stimulus type.

What is receptor specificity?

The sensitivity of receptor cells to limited types of stimuli, known as modality.

What is the difference between sensation and perception?

Sensation is the arrival of information into the CNS, while perception is the awareness of that sensation.

What are exteroceptors?

Receptors that provide information about the external environment.

What are interoceptors?

Receptors that provide information about visceral organs and functions.

What are proprioceptors?

Receptors that provide information about the positions and tension of joints and skeletal muscles.

What types of stimuli do nociceptors respond to?

Pain.

What types of stimuli do thermoreceptors respond to?

Temperature.

What types of stimuli do mechanoreceptors respond to?

Physical distortion.

What types of stimuli do chemoreceptors respond to?

Chemical concentrations.

What types of stimuli do photoreceptors respond to?

Light.

What are tonic receptors?

Receptors that are always active and slowly adapt to stimuli.

What are phasic receptors?

Receptors that are normally inactive but provide a burst of activity when stimulated and quickly adapt.

What is adaptation in sensory receptors?

The reduction in sensitivity of a receptor in the presence of a constant stimulus.

What is peripheral adaptation?

Adaptation that occurs at the level of the receptor, reducing sensory information entering the CNS.

What is central adaptation?

Adaptation that occurs within the CNS, often involving inhibitory interneurons.

What are free nerve endings?

Dendrites that are not protected by accessory structures and are sensitive to many stimuli, including pain and temperature.

What are tactile receptors?

Receptors that provide information about touch, pressure, and vibration.

What is proprioception?

The sense of body position and movement, involving muscle spindles and Golgi tendon organs.

What is referred pain?

Pain perceived at a location other than the site of the painful stimulus.

What substances are involved in pain signaling?

Substance P, Bradykinin, Endorphins, and Enkephalins.

Gap junctions

Allow direct passage of small substances between cells.

Neurotransmitters

Released by neurons and travel a very short distance to the neighboring cell.

Neuroendocrine factors

Released from neurons into the blood; act as hormones.

Paracrine factors

Chemical signals that diffuse to neighboring cells.

Hormones

Chemical signals that travel into the blood to other organs or tissues.

Endocrine glands

Glands that secrete hormones directly into the bloodstream.

Exocrine glands

Glands that secrete substances through ducts to the outside of the body.

Additive effects

When two or more hormones have the same effect that get added together.

Synergistic effects

When two or more hormones acting simultaneously have a multiplying effect on the response.

Permissive effects

Enhance the response to a hormone; permissive hormones are usually required to be present first.

Antagonistic effects

Block or inhibit the action of a hormone.

Signal Amplification

The process by which a small amount of hormone can produce a large effect.

Modulation of Target Cell Sensitivity

Adjusting the sensitivity of target cells to hormones.

Thyroid hormone

Made in follicles, contains iodine, consists of 90% thyroxine (T4) and 10% triiodothyronine (T3).

Calcitonin

Hormone produced by the thyroid gland that helps regulate calcium levels.

Adrenal cortex hormones

Include steroid hormones such as aldosterone, cortisol, and androgens.

Alpha cells

Cells in the pancreas that produce glucagon.

Beta cells

Cells in the pancreas that produce insulin.

Diabetes mellitus

A condition characterized by high blood sugar levels due to insulin issues.

Type 1 diabetes

A form of diabetes where the body does not produce insulin.

Type 2 diabetes

A form of diabetes where the body does not properly use insulin.