A&P Exam 3

Unipolar Neurons

Neurons with one process serving as both axon and dendrite, primarily sensory neurons with cell bodies in ganglia.

Bipolar Neurons

Neurons possessing two processes (one axon and one dendrite) from opposite ends of the cell body, found in olfactory epithelium and the retina.

Multipolar Neurons

Neurons with one axon and multiple dendrites; the most common type of neuron in the CNS.

Astrocytes

Star-shaped glial cells in the CNS that support neurons, maintain chemical balance and the blood-brain barrier.

Satellite Cells

Glial cells in the PNS that surround neuron cell bodies, providing support and regulating the environment.

Schwann Cells

Glial cells that form the myelin sheath around peripheral nerve axons, facilitating rapid electrical signal transmission.

Ligand-Gated Channels

Ion channels that open when a signaling molecule binds, allowing specific ions to cross the membrane.

Mechanically Gated Channels

Ion channels that respond to physical distortions of the cell membrane by allowing ions to enter.

Voltage-Gated Channels

Ion channels that open in response to changes in electrical membrane properties, contributing to action potentials.

Leaky Channels

Ion channels that open and close randomly, contributing to resting membrane potential.

Action Potentials

All-or-nothing electrical signals resulting from the rapid depolarization and repolarization of a neuron's membrane.

Absolute Refractory Period

The period during which no new action potential can be initiated regardless of the stimulus strength.

Relative Refractory Period

The period following an action potential where a stronger-than-normal stimulus is needed to trigger another action potential.

Spatial Summation

The combined effect of graded potentials from different synapses reaching a neuron's threshold.

Temporal Summation

The cumulative effect of multiple graded potentials occurring in rapid succession at the same synapse.

Cerebrospinal Fluid (CSF)

Fluid produced in the brain's ventricles, cushions the CNS, maintains chemical stability, and removes waste.

Basal Nuclei

A group of nuclei in the cerebrum involved in cognitive processing and planning of movements.

List the basal nuclei

caudate nucleus, putamen, and globus pallidus

Horns of Spinal Cord

Regions of gray matter in the spinal cord responsible for sensory processing (posterior), motor output (anterior), and autonomic function (lateral).

Epineurium

The outermost layer of connective tissue surrounding a nerve.

Perineurium

The connective tissue layer that encloses individual fascicles within a nerve.

Endoneurium

The innermost connective tissue layer that surrounds individual axons.

Phrenic Nerve

A nerve originating from the cervical plexus that innervates the diaphragm, critical for breathing.

Proprioceptors

Receptors that monitor body position, movement, and muscle tension.

Rods

Photoreceptors in the retina sensitive to low light, crucial for night vision.

Cones

Photoreceptors in the retina responsible for color vision and function best in bright light.

Auditory Ossicles

Three small bones in the middle ear that transmit sound vibrations from the tympanic membrane to the inner ear.

Crossed Extensor Reflex

A reflex that activates contralateral extensor muscles to maintain balance when the flexor reflex is triggered.

Anterior Corticospinal Tract

consists of fibers that connect the cerebral cortex to the spinal cord, primarily controlling axial muscles.

Ganglionic Neurons

Neurons in autonomic ganglia that relay signals from the CNS to target organs.

Intramural Ganglia

Ganglia located within the walls of target organs where postganglionic neurons synapse.

Sympathetic Activation

Responses activated during 'fight or flight' situations, increasing heart rate and redirecting blood flow.

Parasympathetic Activation

Responses activated during 'rest and digest' states, promoting activities like digestion and lowering heart rate.

Unipolar Neurons

primarily function in sensory pathways, transmitting sensory information from the periphery to the central nervous system.

Bipolar Neurons

found in specific locations such as the retina, where they play a critical role in visual processing.

Multipolar Neurons

Have multiple dendrites and are specialized for integration of signals, common in motor and interneuron roles.

Astrocytes

Help maintain the blood-brain barrier, provide nutrients to neurons, and manage extracellular ion balance.

Satellite Cells

Regulate the chemical environment around neuron cell bodies in ganglia, important for neuronal health.

Schwann Cells

Vital for the regeneration of peripheral nerves, forming the myelin sheath and aiding in signal conduction.

Ligand-Gated Channels

Allow for rapid cellular response to neurotransmitters, essential for synaptic transmission.

Mechanically Gated Channels

Crucial for sensory neurons that respond to pressure or deformation in tissues.

Voltage-Gated Channels

essential for the initiation and propagation of action potentials in excitable cells.

Leaky Channels

play a key role in setting resting membrane potential, allowing ions to flow freely.

Action Potentials

crucial for neuron communication, arising when the membrane potential reaches the threshold.

Absolute Refractory Period

ensures that action potentials are discrete events and prevents backward conduction.

Relative Refractory Period

allows for potential firing of action potentials under stronger-than-normal stimulation.

Spatial Summation

integrates multiple signals from different synapses, determining whether a neuron will fire.

Temporal Summation

allows a series of rapid signals from the same synapse to combine and trigger an action potential.

Cerebrospinal Fluid (CSF)

protects the brain by acting as a cushion, also plays a role in nutrient transport and waste removal.

Basal Nuclei

involved in motor control, cognitive processing, and regulating voluntary movements.

Horns of Spinal Cord

process different sensory and motor functions, including reflexes and pain response.

Epineurium

provides structural integrity and protection to the entire nerve, supporting its function.

Perineurium

serves as a barrier that protects fascicles within a nerve, providing support and isolating them.

Endoneurium

is essential for protecting individual axons and providing them with nutrients and support.

Phrenic Nerve

is crucial for diaphragm movement, thus playing an essential role in respiration.

Proprioceptors

allow the body to monitor and maintain balance and coordination by sensing body position.

Rods

critical for peripheral and night vision, making them essential for low-light conditions.

Cones

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

Auditory Ossicles

are essential for sound transmission, amplifying sound vibrations from the outer ear to the inner ear.

Crossed Extensor Reflex

helps maintain balance by activating opposing limb muscles during withdrawal reflexes.

Anterior Corticospinal Tract

crucial for voluntary control of proximal muscle movements.

Ganglionic Neurons

serve as relay points, transmitting signals from the central nervous system to effector organs.

Intramural Ganglia

facilitate local reflexes and autonomic functions within target organs.

Sympathetic Activation

results in increased heart rate, dilation of airways, and redirecting blood to muscles.

Parasympathetic Activation

promotes digestion, decreases heart rate, and encourages rest and repair processes

Posterior Horn Function

The posterior horn processes sensory information received from the body, including pain and touch.

Anterior Horn Function

The anterior horn contains motor neurons that send signals to skeletal muscles, enabling movement.