A&P test 3

Free Nerve Endings

The simplest receptors, characterized by bare nerve endings that respond to a variety of stimuli, including pain, temperature, and rough touch.

Encapsulated Nerve Endings

Specialized receptors with nerve endings enclosed in connective tissue, including Meissner's corpuscles, Pacinian corpuscles, Ruffini endings, and Golgi tendon organs.

Adequate Stimuli

Specific types of stimuli that a receptor responds to, such as pain for nociceptors, touch for Meissner's corpuscles, light for photoreceptors.

Mechanoreceptors

Receptors that detect physical stimuli like pressure, vibration, touch, and stretch.

Thermoreceptors

Receptors that detect changes in temperature.

Nociceptors

Receptors that detect painful stimuli.

Chemoreceptors

Receptors that detect chemical stimuli related to taste and smell.

Proprioceptors

Receptors that detect body position and movement.

Special Senses

Sensory modalities that rely on specialized organs, such as vision, hearing, taste, and smell.

General Senses

Sensory modalities that are distributed throughout the body, detecting touch, pain, temperature, and proprioception.

Taste Sensations

The basic taste qualities detected by taste receptor cells: sweet, sour, salty, bitter, and umami.

Smell

The sense of smell relies on detecting airborne molecules (odorants) that bind to specialized cells in the nose.

Sensory Adaptation

The process by which our senses become less sensitive to a constant stimulus over time.

Cornea

The transparent, outermost layer of the eye that helps focus light entering the eye.

Iris

The colored part of the eye that controls the amount of light entering the eye by adjusting the size of the pupil.

Pupil

The opening in the center of the iris that allows light to enter the eye.

Lens

A transparent, flexible structure behind the iris that focuses light onto the retina.

Retina

The light-sensitive layer at the back of the eye that converts light into electrical signals.

Optic Nerve

The nerve that carries electrical signals from the retina to the brain for processing.

Sclera

The tough, white outer layer of the eye that protects internal structures.

Choroid

A layer of tissue between the sclera and retina that nourishes the retina and absorbs excess light.

Macula

A small, central area of the retina responsible for sharp, detailed vision.

Fovea Centralis

The center of the macula where the highest concentration of photoreceptor cells (cones) is located.

Rods

Light-sensitive cells in the retina that detect low light levels and enable peripheral vision.

Cones

Photoreceptors in the retina that detect color and function best in bright light.

Visual Pathway

The pathway that light travels from the retina through the optic nerve, optic chiasm, and to the visual cortex.

Aqueous Humor

A clear, watery fluid that fills the anterior cavity of the eye, nourishing the cornea and lens.

Vitreous Humor

A transparent, gel-like substance that fills the space between the lens and retina, helping to maintain the eye's shape.

Eyelids

Movable folds of skin that protect the eye from injury and debris.

Lacrimal Glands

Glands that produce tears to lubricate and protect the eye.

Outer Ear

The external portion of the ear, including the pinna and ear canal, which gathers sound waves.

Middle Ear

Contains the auditory ossicles (malleus, incus, stapes) that amplify sound vibrations and transmit them to the inner ear.

Inner Ear

Contains the cochlea and vestibular system, responsible for hearing and balance.

Cochlea

A spiral-shaped, fluid-filled structure that converts sound vibrations into electrical signals.

Vestibular System

Includes the semicircular canals and other structures that help maintain balance.

Utricle and Saccule

Otolith organs that help detect linear acceleration and spatial orientation.

Cerebral Cortex

The outermost layer of the cerebrum responsible for higher-level functions like thought and memory.

Frontal Lobe

Involved in motor control, planning, and higher cognitive functions.

Parietal Lobe

Processes sensory information such as touch and spatial awareness.

Temporal Lobe

Processes auditory information and is important for memory and language comprehension.

Occipital Lobe

Processes visual information.

Cerebellum

Coordinates voluntary muscle movements and maintains posture and balance.

Brainstem

Regulates vital functions like breathing and heart rate.

Hypothalamus

Regulates body temperature, hunger, thirst, and controls the pituitary gland.

Pituitary Gland

Known as the 'master gland,' it regulates other endocrine glands and releases various hormones.

Endocrine System

System of glands that produce and release hormones into the bloodstream to regulate body functions.

Hormones

Chemical messengers produced by the endocrine system that regulate various bodily functions.

Negative Feedback Mechanism

Common regulatory process where the product of a process inhibits its own production.

Positive Feedback Mechanism

Less common regulatory process where a product enhances its own production.

Gonadotropins

Hormones that regulate the reproductive system, including FSH and LH.

Aldosterone

A steroid hormone produced by the adrenal cortex that regulates sodium and potassium levels.

Thyroid Hormones

Hormones like T3 and T4 that regulate metabolism and energy production.

Calcitonin

Hormone that reduces blood calcium levels by inhibiting osteoclast activity.

Parathyroid Hormone (PTH)

Hormone that increases blood calcium levels by stimulating osteoclast activity.

Neurotransmitters

Chemical messengers that transmit signals across a synapse.

Excitatory Neurotransmitters

Chemical messengers that stimulate nerve impulses.

Inhibitory Neurotransmitters

Chemical messengers that inhibit nerve impulses.

Ion Channel Gating

Process by which a neurotransmitter binding to a receptor opens or closes an ion channel.

Intracellular Receptors

Receptors located inside the cell that bind lipid-soluble hormones to regulate gene expression.

Paracrine Signaling

Cell signaling where a cell releases a signaling molecule that acts on nearby cells.

Autocrine Signaling

Cell signaling where a cell releases a signaling molecule that binds to itself.

Feedback Control Mechanisms

Processes that regulate hormone secretion based on changes in the body.

Hypophyseal Portal System

The vascular connection between the hypothalamus and the anterior pituitary.

Hypothalamic-Hypophyseal Tract

The neural connection between the hypothalamus and the posterior pituitary.