A&P2 Midterm Study Review (Wks 1-4)

What is the function of a neuron?

What are the three main parts of a neuron?

Cell body (soma), dendrites, and axon.

What is the function of dendrites?

Receive incoming signals.

What is the function of the cell body (soma)?

Contains the nucleus and performs the neuron’s metabolic functions.

What is the function of the axon?

Carries nerve impulses away from the cell body.

What is the axon hillock?

The region where action potentials begin.

What is myelin?

A fatty insulating covering that speeds nerve impulse conduction.

What is the function of the nodes of Ranvier?

Allow saltatory conduction, making impulses travel faster.

What are glial cells?

Support cells that protect, nourish, and insulate neurons.

What are the four CNS glial cells and their functions?

• Astrocytes – support neurons and help form the blood-brain barrier.

• Oligodendrocytes – produce myelin in the CNS.

• Microglia – immune defense and phagocytosis.

• Ependymal cells – produce and circulate CSF.

What are the two PNS glial cells?

• Schwann cells – produce myelin in the PNS.

• Satellite cells – support neuron cell bodies in ganglia.

What is the resting membrane potential?

About -70 mV.

What causes depolarization?

Voltage-gated sodium channels open, allowing Na⁺ to enter the cell.

What causes repolarization?

Voltage-gated potassium channels open, allowing K⁺ to leave the cell.

What is hyperpolarization?

The membrane becomes more negative than resting potential because K⁺ channels remain open briefly.

What restores the resting membrane potential?

The sodium-potassium pump (3 Na⁺ out, 2 K⁺ in).

What is the threshold potential?

Approximately -55 mV.

What is the all-or-none principle?

Once threshold is reached, the neuron fires a complete action potential.

What is the refractory period?

A period when another action potential cannot or is less likely to occur.

What is a synapse?

The junction between two neurons.

What happens when an action potential reaches the axon terminal?

1. Calcium channels open.

2. Calcium enters.

3. Neurotransmitters are released.

4. Neurotransmitters bind receptors.

5. Ion channels open or close.

How are neurotransmitters removed?

• Reuptake

• Enzymatic breakdown

• Diffusion

What is a neurotransmitter?

 A chemical messenger released by neurons.

Which neurotransmitter controls skeletal muscle?

Acetylcholine (ACh)

Which neurotransmitter is associated with movement and reward?

Dopamine

Which neurotransmitter regulates mood?

Serotonin

Which neurotransmitter is the primary excitatory neurotransmitter?

Glutamate

Which neurotransmitter is the primary inhibitory neurotransmitter?

GABA

Which neurotransmitter is involved in the fight-or-flight response?

Norepinephrine

What is an agonist?

A drug that activates a receptor.

What is an antagonist?

A drug that blocks a receptor.

A drug that blocks a receptor.

• Mimic neurotransmitters.

• Block receptors.

• Increase neurotransmitter release.

• Prevent neurotransmitter breakdown.

• Block reuptake.

What structures make up the CNS?

Brain and spinal cord.

What structures make up the PNS?

Cranial nerves, spinal nerves, and ganglia.

How many spinal nerves are there?

31 pairs.

spinal nerve regions.

• 8 Cervical

• 12 Thoracic

• 5 Lumbar

• 5 Sacral

• 1 Coccygeal

What is a dorsal root?

Sensory (afferent).

What is a ventral root?

Motor (efferent).

Where are sensory neuron cell bodies located?

Dorsal root ganglion.

What are the meninges?

1. Dura mater

2. Arachnoid mater

3. Pia mater

Where is CSF located?

Subarachnoid space.

What is gray matter?

Neuron cell bodies, dendrites, and synapses.

What is white matter?

Myelinated axons.

What is found in the dorsal horn?

Sensory neurons.

What is found in the ventral horn?

Motor neurons.

What is found in the lateral horn?

Autonomic neurons (thoracic/lumbar only).

What are mechanoreceptors?

Respond to touch, pressure, vibration, and hearing.

What are thermoreceptors?

Respond to temperature.

What are nociceptors?

Respond to pain.

What are chemoreceptors?

Respond to chemicals.

What are photoreceptors?

Respond to light.

What are proprioceptors?

Detect body position and movement.

What does the somatic nervous system control?

Voluntary skeletal muscle.

What does the autonomic nervous system control?

Involuntary smooth muscle, cardiac muscle, and glands.

What is a reflex?

A rapid automatic response to a stimulus.

List the components of a reflex arc.

1. Receptor

2. Sensory neuron

3. Integration center

4. Motor neuron

5. Effector

What are the four major brain regions?

• Cerebrum

• Diencephalon

• Brainstem

• Cerebellum

What are the brain meninges?

• Dura mater

• Arachnoid mater

• Pia mater

What is cerebrospinal fluid (CSF)?

A clear fluid that cushions and nourishes the CNS.

Where is CSF produced?

Choroid plexus.

What is the blood-brain barrier (BBB)?

A selective barrier that protects brain tissue from harmful substances.

What are gyri?

Raised ridges of the brain.

What are sulci?

Shallow grooves.

What is a fissure?

A deep groove separating brain regions.

What are the four cerebral lobes?

• Frontal

• Parietal

• Temporal

• Occipital

Where is the primary motor cortex?

Precentral gyrus.

Where is the primary somatosensory cortex?

Postcentral gyrus.

What is the motor homunculus?

 A map showing body representation in the motor cortex.

What is the sensory homunculus?

A map showing body representation in the sensory cortex.

What does the prefrontal cortex control?

Planning, judgment, personality, and decision-making.

What is Broca’s area?

Motor speech production.

What is Wernicke’s area?

Language comprehension.

Where is the visual cortex?

Occipital lobe.

Where is the auditory cortex?

Temporal lobe.

What structures make up the diencephalon?

• Thalamus

• Hypothalamus

• Epithalamus (pineal gland)

What is the function of the thalamus?

Relay station for sensory information.

What is the function of the hypothalamus?

Maintains homeostasis; regulates temperature, hunger, thirst, hormones, and autonomic functions.

What is the function of the pituitary gland?

Secretes hormones controlling many endocrine glands.

What is the function of the pineal gland?

Produces melatonin and regulates sleep.

What are the three parts of the brainstem?

• Midbrain

• Pons

• Medulla oblongata

What does the midbrain control?

Visual and auditory reflexes.

What does the pons control?

Relay center; helps regulate breathing.

What does the medulla oblongata control?

Heart rate, breathing, blood pressure, and swallowing.

What is the function of the cerebellum?

Balance, posture, and coordination.

What are the basal nuclei?

Control initiation and smooth movement.

What is the hippocampus?

Memory formation.

What is the amygdala?

Emotion and fear.

What is the olfactory bulb/tract?

Sense of smell.

What is the primary motor cortex?

Initiates voluntary movement.

What is the speech center?

Broca’s area (speech production).

What do motor areas control?

Voluntary movement.

What do proprioceptors detect?

What do proprioceptors detect?

What structures of the inner ear control balance?

Semicircular canals, utricle, and saccule.

What causes Parkinson’s disease?

Loss of dopamine-producing neurons in the substantia nigra.

Loss of dopamine-producing neurons in the substantia nigra. Parkinson’s

• Tremor

• Rigidity

• Slow movement (bradykinesia)

• Balance problems

What causes Alzheimer’s disease?

Accumulation of amyloid plaques and tau tangles leading to neuron death.

Common symptoms? Alzheimer’s

• Memory loss

• Confusion

• Difficulty learning

• Personality changes

What structures belong to the limbic system?

• Hippocampus

• Amygdala

• Hypothalamus

• Cingulate gyrus

What are the functions of the limbic system?

Emotion, motivation, memory, and behavior.

What are the two divisions of the ANS?

• Sympathetic

• Parasympathetic