Comparative Anatomy: Nervous System Flashcards

Flashcards covering the nervous system, neurons, brain parts, senses, and adaptations.

Central Nervous System

Consists of the brain and spinal cord.

Peripheral Nervous System

A network of nerves and neural tissues branching out throughout the body.

Neurons

Nerve cells; the structural and functional units of the nervous system.

Neuroglia

Tissues that support the nerve cells.

Motor Neurons

Neurons that cause muscle contractions and control secretions from glands and organs.

Sensory Neurons

Neurons attached to sensory receptors that transmit impulses to the central nervous system.

Interneurons

Neurons located entirely within the central nervous system that intercept impulses and transmit signals to motor neurons.

Afferent Nerves

Conduct impulses to the central nervous system.

Efferent Nerves

Conduct impulses to the muscles, organs, and glands.

Synapses

Connectors hooking dendrites and axons from one neuron to another, transmitting nerve impulses.

Gray Matter

Consists of unsheathed nerve fibers in the cortex or surface layer of the brain and spinal cord.

White Matter

Consists of myelinated nerve fibers making up the internal structure of the brain and spinal cord.

Meninges

The three membranes enclosing the brain and spinal cord: dura mater, arachnoid, and pia mater.

Cerebrum

Governs all sensory and motor activity, including sensory perception, emotions, consciousness, memory, and voluntary movements.

Cerebellum

Coordinates voluntary and involuntary patterns of movements and adjusts muscles to maintain posture.

Diencephalon

Refers to the thalamus and hypothalamus.

Thalamus

Relay center for all sensory impulses except olfactory.

Hypothalamus

Regulates behavior and emotional expression, body temperature, and many metabolic activities; controls hormonal secretions of the pituitary gland.

Brainstem

Consists of the midbrain, pons, and medulla oblongata.

Midbrain

Controls visual reflexes and sense of hearing.

Pons

Plays a role in regulating visceral control.

Medulla Oblongata

Connects the rest of the brain to the spinal cord and regulates breathing, swallowing, heartbeat, and blood pressure.

Cerebrospinal Fluid

Cushions the brain and spinal cord from shocks.

Olfactory Nerve

Carries sensory input for smell (cranial nerve I).

Optic Nerve

Carries sensory input for vision (cranial nerve II).

Oculomotor Nerve

Controls muscles of the eye and eyelid (cranial nerve III).

Trochlear Nerve

Controls the eyeball (cranial nerve IV).

Trigeminal Nerve

Controls the face, nose, mouth, forehead, top of head, and jaw (cranial nerve V).

Abducens Nerve

Controls the eyeball (cranial nerve VI).

Facial Nerve

Controls muscles of the face and scalp, and part of the tongue for sense of taste (cranial nerve VII).

Auditory (Cochlear) Nerve

Provides sensory input for hearing and equilibrium (cranial nerve VIII).

Glossopharyngeal Nerve

Controls saliva, swallowing, and taste (cranial nerve IX).

Vagus Nerve

Extends to and controls the heart, lungs, stomach, and intestines (cranial nerve X).

Accessory Nerve

Permits movement of the head and shoulders (cranial nerve XI).

Hypoglossal Nerve

Controls the muscles of the tongue (cranial nerve XII).

Autonomic Nervous System

Controls involuntary bodily functions such as sweating, gland secretions, blood pressure, and the heart.

Sympathetic Nervous System

Responsible for the 'flight or fight' responses.

Parasympathetic Nervous System

Counteracts the responses of the sympathetic system, restoring homeostasis.

Sensations

Result from stimuli that initiate afferent impulses.

Exteroceptors

Detect stimuli near the outer body surface.

Interoceptors

Detect stimuli from inside the body.

Proprioceptors

Detect stimuli deep within the body, located in skeletal muscles, tendons, ligaments, and joint capsules.

Sensory Receptor

Peripheral component of an afferent axon that converts different types of energy into nerve signals.

Pain Receptor

Receptors termed nociceptors; bare nerve endings of pain neurons.

Gustation

Sense of taste.

Taste Bud

Receptor organ for taste, found on the tongue, palate, pharynx, and larynx.

Gustatory Cells

Receptors for taste within taste buds.

Olfaction

Sensation of smell.

Macrosmatic

Animals with a greatly developed sense of smell.

Microsmatic

Animals with a less developed sense of smell (e.g., humans and monkeys).

Anosmatic

Animals with no sense of smell.

Pheromone

A chemical secreted by one animal that influences the behavior of another.

Auditory Tube (Eustachian Tube)

Allows for pressure equalization in the middle ear.

Inner Ear Functions

Vestibular portion (sensory for position and balance) and cochlear portion (sensory for sound).

Auditory Ossicles

The ossicles of the middle ear – incus (anvil), malleus (hammer), and stapes (stirrup).

Membranous Labyrinth

Contains a fluid known as endolymph.

Osseous Labyrinth

Contains a fluid known as perilymph.

Crista Ampullaris

Sensory receptors for equilibrium located in the ampullae.

Macula

Sensory receptor area located in the utricle and saccule.

Cochlear Duct (Scala Media)

Extension of the membranous labyrinth into the cochlea.

Organ of Corti

Structures within the scala media that convert sound waves to nerve impulses.

Sclera

Outer layer of the eye; the white of the eye.

Cornea

Clear part of the sclera at the front of the eye, allowing light to pass through.

Choroid Coat

Middle layer of the eye, containing blood vessels.

Pupil

Circular opening in the choroid coat.

Iris

Colored, muscular layer surrounding the pupil, controlling the amount of light entering the eye.

Lens

Focuses light rays on the retina.

Aqueous Humor

Watery fluid filling the anterior chamber of the eye.

Vitreous Humor

Jellylike substance filling the posterior chamber of the eye.

Retina

Innermost layer of the eye where light rays focus an image.

Rods

Specialized cells in the retina sensitive to dim light.

Cones

Specialized cells in the retina sensitive to bright light and responsible for color vision.

Optic Disc

Site on the retina where nerve fibers gather to form the optic nerve; the blind spot.

Echolocation

Helps bats navigate and locate prey in darkness by emitting high-frequency sound waves and interpreting the echoes that bounce back.