BIO 120 Unit 4 Practice Exam

A set of vocabulary flashcards for the BIO 120 Unit 4 Practice Exam covering the nervous system's structure, function, and related concepts.

Nervous System

Monitors internal and external stimuli, transmits electrical impulses, and maintains homeostasis.

Dura Mater

The tough, outermost membrane covering the brain and spinal cord.

Arachnoid Mater

The middle meningeal layer resembling a spider web.

Pia Mater

The layer of the meninges that lies directly on the brain surface and contains many blood vessels.

Cerebral Cortex

The outer gray-matter region of the cerebrum responsible for conscious thought.

Corpus Callosum

Connects the right and left cerebral hemispheres.

Thalamus

Primarily functions as a sensory relay station.

Primary Somatosensory Cortex

The area where sensory information such as pain, pressure, and temperature is perceived.

Hypothalamus

Brain structure that helps regulate the sleep-wake cycle.

Brainstem

Composed of the midbrain, pons, and medulla oblongata.

Medulla Oblongata

Helps regulate heart rate and blood vessel diameter.

Pons

Region of the brain that regulates breathing rhythm.

Cerebellum

Main function is to coordinate movement and balance.

Blood-Brain Barrier (BBB)

Limits entry of many substances into the brain.

Cerebrospinal Fluid (CSF)

Produced by ependymal cells; flows through ventricles and protects the brain.

Astrocytes

Form part of the BBB by creating tight junctions.

Oligodendrocytes

Function to form myelin sheaths in the CNS.

Microglia

Phagocytic immune cells of the CNS.

Cranial Nerves

There are 12 pairs of cranial nerves.

Optic Nerve (CN II)

Transmits visual information.

Oculomotor Nerve (III)

Controls eyelid movement and pupil constriction.

Trochlear Nerve (IV)

Controls eye movement.

Trigeminal Nerve (V)

Provides both sensory and motor functions to the face.

Vestibulocochlear Nerve (VIII)

Carries signals for hearing and equilibrium.

Vagus Nerve (X)

Helps decrease heart rate and promote digestion.

Accessory Nerve (XI)

Controls head and shoulder movements.

Hypoglossal Nerve (XII)

Controls tongue for speech and swallowing.

Spinal Cord

Extends from the foramen magnum to L1–L2.

Spinal Nerves

There are 31 pairs of spinal nerves.

White Matter

Primarily contains myelinated axons.

Gray Matter

Contains cell bodies and is organized in horns.

PNS

Divided into somatic and autonomic divisions.

Sensory Division

Carries impulses from PNS to CNS.

Brachial Plexus

Innervates shoulder and upper limb.

Mixed Spinal Nerves

Contain both sensory and motor fibers.

Ventral Root

Carries motor information.

Dorsal Root

Carries sensory information.

Interneuron

A neuron that connects other neurons in the CNS.

Myelin Sheath

Functions to increase the speed of conduction.

Saltatory Conduction

Occurs along myelinated axons.

Perception

Conscious awareness of a sensation.

Afferent Pathways

Carry impulses from receptors to the brain.

Proprioceptors

Detect body position and movement.

Nociceptors

Detect pain.

Reflex Arc

Begins when a receptor is stimulated.

Stretch Reflex

Causes contraction after stretch.

Integration Centers

For cranial reflexes are located in the brainstem.

Reflex

Automatic and involuntary response.

Axon

The part of a neuron that carries impulses away from the cell body.

Synaptic Vesicles

Store and release neurotransmitters.

Presynaptic Axon Terminal

Location where neurotransmitters are released.

Membrane Potential

The electrical difference across a neuron membrane.

Resting Membrane Potential

Is negative inside and positive outside the membrane.

Ligand-Gated Channels

Open in response to ligand binding.

Voltage-Gated Channels

Open when the membrane voltage changes.

Action Potentials

Are all-or-none electrical impulses.

Depolarization

Occurs when Na⁺ ions enter the neuron.

Repolarization

Occurs when K⁺ ions leave the cell.

Absolute Refractory Period

No new action potential can form.

Afterpotential

Temporary hyperpolarization phase.

Inhibitory Postsynaptic Potential (IPSP)

Produced by the outflow of K⁺.