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EXAM 4

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Terms in this set (23)

  • What is a resting membrane potential? What is the charge inside the cell?

    The electrical charge of a neuron when it is not sending a signal.

    • Inside the cell is negative (−).

    • Resting potential is about −70 mV.

  • What are the functions of neuroglia cells?

    PNS (Nerves Outside Brain & Spinal Cord)

    Satellite cells: Surround, protect, and support neuron cell bodies.

    Schwann cells: Make myelin in the PNS to speed up nerve signals.

    CNS (Brain & Spinal Cord)

    Astrocytes: Support and nourish neurons; help form the blood-brain barrier.

    Microglial cells: Clean up waste and destroy germs.

    Ependymal cells: Line ventricles and help produce and circulate CSF.

    Oligodendrocytes: Make myelin in the CNS to speed up nerve signals.

  • Define depolarization, hyperpolarization, and repolarization.

    • Depolarization: Na⁺ enters → inside becomes more positive.

    • Repolarization: K⁺ leaves → inside becomes negative again.

    • Hyperpolarization: Too much K⁺ leaves → inside becomes extra negative.

  • What happens during the phases of an action potential?

    • Resting: −70 mV, inside negative.

    • Depolarization: Na⁺ enters → positive.

    • Repolarization: K⁺ exits → negative.

    • Hyperpolarization: Extra K⁺ exits → more negative than resting.

    • Return to rest: Goes back to −70 mV.

  • What does “all or none” mean?

    If a neuron reaches its threshold, it fires a full action potential. If it doesn't, it won't fire.

  • What are the functions of the dorsal root, dorsal root ganglia, and ventral root?

    • Dorsal root: Brings sensory signals INTO the spinal cord.

    • Dorsal root ganglion: Contains sensory neuron cell bodies.

    • Ventral root: Sends motor signals OUT to muscles

  • Describe the 3 layers of meninges.

    • Dura mater: Tough outer layer.

    • Arachnoid mater: Web-like middle layer.

    • Pia mater: Thin inner layer attached to the brain and spinal cord.

  • What are the functions of cerebrospinal fluid (CSF)?

    CSF cushions, protects, and supports the brain and spinal cord. It also helps transport nutrients and remove waste.

  • What do the posterior, anterior, and lateral horns of gray matter do?

    • Posterior (dorsal) horn: Receives sensory information.

    • Anterior (ventral) horn: Sends motor signals to skeletal muscles.

    • Lateral horn: Contains autonomic motor neurons, especially sympathetic neurons.

  • List the 4 major plexuses, their functions, and one major nerve for each.

    Cervical: Neck and diaphragm. Phrenic

    Brachial: Shoulders, arms, hands. Radial

    Lumbar: Front of thighs and parts of legs. Femoral

    Sacral: Buttocks, back of legs, feet. Sciatic

  • What is a stretch reflex, withdrawal reflex, and crossed extensor reflex?

    • Stretch reflex: Muscle stretches → contracts automatically. Example: knee-jerk reflex.

    • Withdrawal reflex: Pulls your body away from pain. Example: pulling your hand from something hot.

    • Crossed extensor reflex: Opposite leg straightens to support your body when the other leg withdraws.

  • Know the names, numbers, and functions of the 12 cranial nerves

    Accessory: Shoulder, neck movement

    Hypoglossal: Tongue movement

    Olfactory: Smell

    Optic: Vision

    Oculomotor: Eye movement, pupil constriction

    Trochlear: Eye movement

    Trigeminal: Face sensation, chewing

    Abducens: Moves eye outward

    Facial: Facial expressions, taste

    Vestibulocochlear: Hearing, balance

    Glossopharyngeal: Taste, swallowing

    Vagus: Heart, lungs, digestion

  • What are the 4 ventricles? What fills them?

    The ventricles are spaces inside the brain filled with cerebrospinal fluid (CSF).

    • 2 lateral ventricles: One in each cerebral hemisphere.

    • 3rd ventricle: In the diencephalon.

    • 4th ventricle: Between the brainstem and cerebellum.

  • What is the blood-brain barrier (BBB)? What can pass through it?

    A protective barrier that keeps harmful substances out of the brain.

    • Can pass: Oxygen, carbon dioxide, and fat-soluble substances. Glucose passes using transporters.

    • Cannot easily pass: Many toxins, large proteins, and most germs.

  • Functions of the brainstem and cerebellum.

    Midbrain: Vision, hearing reflexes, eye movement

    Pons: Helps control breathing; connects brain regions

    Medulla: Controls heart rate, breathing, blood pressure

    Cerebellum: Balance, coordination, posture

  • Functions of the thalamus, hypothalamus, limbic system, and pineal gland.

    • Thalamus: Relay station for sensory information (except smell).

    • Hypothalamus: Controls hunger, thirst, body temperature, and autonomic functions.

    • Limbic system: Emotions and memory.

    • Pineal gland: Produces melatonin for sleep.

  • What are the functions of the brain lobes?

    Frontal: Thinking, planning, movement, speech production

    Parietal: Touch, pressure, temperature, pain

    Temporal: Hearing, memory, language understanding

    Occipital: Vision

    Insula: Taste, internal body sensations

  • Difference between sympathetic and parasympathetic nervous systems.

    Sympathetic = (Emergency)

    • Increase heart rate.

    • Increase breathing.

    • Dilate pupils.

    • Dilates airways.

    • Decreases digestion.

    • Increase blood glucose.

    • Stimulates sweating.

    Parasympathetic = (Relaxing)

    • Slows heart rate.

    • Constricts pupils.

    • Constricts airways.

    • Increases digestion.

    • Increases saliva production.

  • What are the functions of the medulla, hypothalamus, and limbic system?

    • Medulla: Controls heart rate, breathing, and blood pressure.

    • Hypothalamus: Main control center of the ANS. Controls hunger, thirst, temperature, and fluid/electrolyte balance.

    • Limbic system: Controls emotions and emotional responses.

  • Why is pain important? What is referred pain? Give examples.

    Pain warns the body about injury or danger. Referred pain felt somewhere different from where the problem actually is.

    Examples:

    • Heart attack → left arm or jaw pain.

    • Gallbladder problem → right shoulder pain.

    • Diaphragm irritation → shoulder pain.

  • Describe the olfactory nerve pathway.

    1.Odor molecules in nose

    2.Olfactory receptors

    3.Olfactory nerve (CN I)

    4.Olfactory bulb → Olfactory tract

    5.Olfactory cortex (Brain recognizes smell)

  • Describe the visual pathway, including eye structures.

    Visual pathway (memorize in order):

    Cornea → Pupil → Lens → Retina

    Optic nerve → Optic chiasm

    Optic tract → Thalamus

    Optic radiations → Occipital cortex

    Cornea: Clear front; bends light

    Iris: Colored part; controls pupil size

    Pupil: Hole where light enters

    Lens: Focuses light

    Anterior cavity: Front cavity filled with aqueous humor

    Aqueous humor: Fluid that nourishes and maintains eye pressure

    Posterior cavity: Large space behind lens

  • Describe the hearing pathway, including ear structures.

    Hearing pathway (memorize in order):

    Auricle → Ear canal → Eardrum

    Malleus → Incus → Stapes

    Oval window → Cochlea → Hair cells

    Vestibulococh